JP2015199057A - Dispersion type polymer coagulant, soil solidifying agent and coagulation and sedimentation agent, and contamination spreading prevention method of radioactive substance, decontamination method of contaminated soil, vegetation base creation method and water cleaning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a dispersion type polymer coagulant not only capable of effectively performing soil solidification without blocking growth of plant but also capable of being applied to efficient water purification.SOLUTION: An opaque or opalescent colloidal aqueous solution contains a cationic polymer and an anionic polymer and, when either polymer is set as a first polymer and the other polymer is set as a second polymer, causes the first polymer to be excessively compounded as compared to the second polymer such that a value (C/EW) obtained by dividing a compounding amount (C) of the first polymer with an ion equivalent mass (EW) of the first polymer and a value (C/EW) obtained by dividing a compounding amount (C) of the second polymer with an ion equivalent mass (EW) of the second polymer satisfy the following relation and does not produce sediment: (C/EW)/(C/EW)>1.

Description

  The present invention not only enables effective soil solidification without inhibiting plant growth, but also is an environmentally friendly dispersion polymer flocculant that can be applied to efficient water purification and the dispersion polymer flocculant. The present invention relates to a coagulating sedimentation agent excellent in soil solidifying agent and coagulation performance. The present invention also relates to a method for preventing contamination of radioactive substances using the soil solidifying agent, a method for decontamination of contaminated soil, a method for creating a vegetation base, and a water purification method using the coagulating precipitant.

  An ionic organic polymer is an organic polymer having at least one of a cation group and an anion group in one molecule, and has a characteristic behavior and is applied to various uses. For example, a cationic, anionic or amphoteric polymer flocculant is used to agglomerate, settle and separate solids from a suspension contained in domestic wastewater, industrial wastewater, etc. It has been proposed to use a water-soluble polymer flocculant as a method for dewatering sludge.

  Patent Document 2 proposes the use of an ionic organic polymer as a soil solidifying agent for vegetation base construction. The vegetation base construction method disclosed in Patent Document 2 is a mixture of a vegetation base material containing water, a soil component, and an anionic water-soluble organic polymer compound, and a nodule containing a cationic polymer compound. It utilizes the fact that both ionic polymers react to form a gel structure. Vegetation foundation creation is performed as creation of a greening foundation that contributes to the germination, growth or well-balanced growth of plants and also contributes to environmental conservation.

  In Patent Document 3, it is possible to apply an insoluble polyion complex composite comprising both components to applications such as fibers, films, coating films, fillers, etc. by mixing solutions of ionic polymers having different polarities. Proposed.

  Patent Documents 4 and 5 and Non-Patent Document 1 propose that the polyion complex is applied as a decontamination method for radioactive cesium-contaminated soil, in addition to the above-described uses.

  In the decontamination methods described in Patent Documents 4 and 5, when the polyion complex is used as an aqueous solution containing both a polycation and a polyanion, a salt of 2 to 6 wt% is formed so that no gel-like precipitate is formed in the aqueous solution. (Sodium chloride, potassium chloride, potassium sulfate, ammonium sulfate, etc.) are added.

  Non-Patent Document 1 discloses a natural polyion complex solution or a synthetic polyion complex solution as a fixing agent used for removing radioactive cesium from the soil surface layer. Here, the natural polyion complex solution is a solution containing 3 kg of a cationic polymer (HECHPTA) and 1 kg of an anionic polymer (CMC) in a salt solution in which potassium chloride or sodium chloride is added to water at a salt concentration of 2%. In addition, a synthetic polyion complex solution obtained by dissolving with stirring is prepared by adding a cationic polymer (PDADMAC) 4 to a salt solution in which sodium chloride and sodium hydroxide having a salt concentration of 5% are added to water. It is described that it is obtained by adding a solution containing 2 kg and 0.87 kg of anionic polymer (PAA), and dissolving with stirring. The blend amount of the polyion complex solution described in Non-Patent Document 1 is adjusted so that the charge ratio between the cationic polymer and the anionic polymer is approximately 1.

JP 2013-215708 A JP 2006-57276 A JP 2005-206655 A JP 2013-185941 A JP 2014-6111 A

Naganawa Hirochika, Kumazawa Noriyuki, and 8 others, “Removal of radioactive cesium from soil surface using polyion complex as a fixing agent”, Japanese Atomic Energy Society Journal, 2011, Vol. 10, No. 4, p. 227-234

  In the polyion complex, when the anion charge and the cation charge are balanced and the total charge approaches zero, a cohesive force is generated and a precipitate is easily generated. Therefore, when an ionic organic polymer is applied as a flocculant or a soil solidifying agent, an anionic polymer and a cationic polymer are used depending on the charge of the solid contained in the sludge or soil suspension. Either of these is used, or an amphoteric polymer is used as described in Patent Document 1. In some cases, it may be used in combination with a nonionic polymer flocculant. However, these methods have a problem that the granulation effect of enlarging flocs produced by partially agglomerating sludge, soil, etc. to a diameter that can be easily separated as aggregates is not obtained. For this reason, there are cases where it is used in combination with another granulating material, and it is inevitable that the processing becomes complicated. In addition, amphoteric flocculants are difficult to design materials and are subject to application restrictions in terms of material costs.

  As disclosed in Patent Documents 2 and 3, instead of using the ionic organic polymer alone, the cationic polymer and the anionic polymer are used as separate components, and they are aggregated by mixing them together. A method to express force is adopted. In that case, since it is necessary to prepare a plurality of containers for storing the two components and to separate each processing twice or more, the processing becomes complicated as compared with the case of only one component. Also, domestic wastewater, industrial wastewater or soil has different types, contents, pH, charge, etc. of each component contained in them depending on the location and environment. If they are added separately, it is difficult to obtain stable characteristics and performance as a flocculant due to differences in penetrability and cohesive force. For example, when applying to a wide range of areas with different properties, it takes a long time to spray one of the cationic polymer and the anionic polymer before spraying the other polymer. Become prominent. Moreover, when spraying two liquids with a nozzle or the like, since the gelation reaction of both occurs in a state where the liquid is not sufficiently infiltrated, there is a great restriction on the range and depth of soil that can be immobilized. Thus, using a cationic polymer and an anionic polymer as separate components as the flocculant cannot perform efficient and rapid processing, and the application range is limited.

  Therefore, in the decontamination methods for radioactive cesium-contaminated soils described in Patent Documents 4 and 5 and Non-Patent Document 1, radioactive water is used by using an aqueous solution containing a polyion complex composed of a cationic polymer and an anionic polymer. A method has been proposed in which the migration of cesium to the soil depth is suppressed to prevent the expansion of radioactive material contamination, and the topsoil of the contaminated soil is solidified and exfoliated. Although these methods are effective decontamination methods, salts such as sodium chloride, potassium chloride, potassium sulfate, ammonium sulfate and the like are added to suppress the formation of precipitates of the polyion complex. In that case, the properties and quality of the soil sprayed with the polyion complex may be greatly changed by the added salt, and there may be a concern about the environmental impact that it becomes difficult to grow plants and crops in the future. Although it is possible to regenerate the soil by neutralizing the salt contained in the soil, it requires not only a great effort and effort, but also takes time to complete the soil regeneration. Therefore, there is a strong demand for a soil solidifying agent that can reduce the burden on the environment as much as possible and a simple, rapid, and efficient treatment method using the soil solidifying agent as well as a method for preventing the spread of radioactive material contamination and a method for decontaminating contaminated soil. It has been.

  The present invention has been made in view of the above-described conventional problems, and is not only capable of effective soil solidification without inhibiting plant growth, but also can be applied to efficient water purification. An object is to provide an environmentally friendly soil solidifying agent comprising a molecular flocculant and the dispersion-type polymer flocculant and a flocculant precipitant having excellent flocculant performance. Another object of the present invention is to provide a method for preventing contamination of radioactive substances using the soil solidifying agent, a method for decontamination of contaminated soil, a method for creating a vegetation base, and a method for water purification using the coagulating sedimentation agent.

  The inventor of the present invention pays attention to an aqueous solution containing a cationic polymer and an anionic polymer as a polymer flocculant that is excellent in handleability and can obtain a large cohesive force only by adding the ionic polymer. An aqueous solution obtained by adding one of the above to another ionic polymer in excess at a charge ratio and mixing to form a uniform colloidal aqueous solution that is stable for a long period of time without forming a precipitate, The inventors have found that a large cohesive force can be expressed when added to industrial wastewater or soil, etc., and have reached the present invention.

That is, the configuration of the present invention is as follows.
[1] The present invention is an aqueous dispersion type polymer flocculant containing a cationic polymer and an anionic polymer, wherein the cationic polymer and the anionic polymer are either one of the polymers. The first polymer is the second polymer, the other polymer is the second polymer, and the compounding amount (C ₁ ) of the first polymer is the ion equivalent mass (EW ₁ ) of the first polymer. and dividing a value _{(C 1} / EW 1), the second amount of the polymer _{(C 2)} value divided by the second ion equivalent mass polymer has (EW ₂₎ a _(C 2 / EW ₂ ) and (C ₁ / EW ₁ ) :( C ₂ / EW ₂ ) = 1: 1, and the charge ratio is 1, then (C ₁ / EW ₁ ) / (C ₂ / EW _2)> so as to satisfy a relation, which is excessively blended than the first polymer and the second polymer, One, the aqueous solution does not produce a precipitate, provides a distributed polymer flocculant, characterized in that it is opaque or milky colloid solution.
[2] In the present invention, the colloidal aqueous solution may be sodium chloride, potassium chloride, ammonium chloride, magnesium chloride, sodium sulfate, potassium sulfate as a salt other than the counter ion contained in the cationic polymer or the anionic polymer. When the total amount of the aqueous colloidal solution is 100 parts by mass including at least one salt selected from ammonium sulfate, magnesium sulfate, sodium nitrate, potassium nitrate, and ammonium nitrate, The dispersion type polymer flocculant according to the above [1], wherein the total concentration is less than 1.5% by mass.
[3] In the present invention, the first polymer has a charge ratio that is a value obtained by dividing (C ₁ / EW ₁ ) by (C ₂ / EW ₂ ) with respect to the second polymer. [2], wherein the compounding amount is twice or more, and the colloidal aqueous solution does not contain a salt other than a counter ion contained in the cationic polymer or the anionic polymer. Dispersed polymer flocculants as described are provided.
[4] In the present invention, when the first polymer is excessively blended with the second polymer, the upper limit of the blending amount is a translucent or milky white in which the colloidal aqueous solution does not form a precipitate. The dispersion type polymer flocculant according to any one of the above [1] to [3], wherein the blending amount is such that a uniform state can be maintained.
[5] In the present invention, the cationic polymer is at least one selected from cationized cellulose, cationized starch, a polymer having an amino group, or a polymer of a quaternary ammonium salt, and the anionic polymer Is at least one selected from carboxymethyl cellulose, carboxymethyl amylose, lignin sulfonic acid and its salt, polyacrylic acid and its salt, polysulfonic acid and its salt [1] to [4] A dispersion-type polymer flocculant as described in any of the above is provided.
[6] The present invention provides the dispersion polymer flocculant according to any one of [1] to [5], wherein the aqueous colloidal solution is a combination of the cationic polymer and the anionic polymer. Provided is a soil solidifying agent characterized in that it contains molecules in a range of more than 0.5 g and not more than 10 g with respect to 100 ml of the colloidal aqueous solution.
[7] The present invention provides the dispersion polymer flocculant according to any one of [1] to [5], wherein the aqueous colloidal solution is a combination of the cationic polymer and the anionic polymer. There is provided an aggregated precipitant characterized by containing molecules in a range of more than 0.1 g and not more than 10 g with respect to 100 ml of the colloidal aqueous solution.
[8] The present invention is obtained by pulverizing a solid obtained as a residue after removing water from the dispersed polymer flocculant according to any one of [1] to [5] or the solid. The present invention provides a coagulating and precipitating agent characterized by being a powdery product.
[9] The present invention provides a radioactive substance that prevents migration and diffusion of radioactive substances by spraying the soil solidifying agent according to [6] above on soil contaminated with radioactive cesium, and then fixing the soil. Provide methods to prevent the spread of contamination.
[10] The present invention peels and removes the surface layer of the soil after spraying the soil solidifying agent according to [6] above to the soil contaminated with radioactive cesium to fix at least a part of the soil. A decontamination method for contaminated soil is provided.
[11] In the present invention, radioactive cesium is dispersed in the clay fine particles by spraying a suspension having clay fine particles and the soil solidifying agent described in [6] in this order on soil contaminated with radioactive cesium. The present invention provides a method for preventing the radioactive material from spreading and preventing the movement and diffusion of the radioactive material by solidifying the soil containing the clay fine particles incorporated with the radioactive cesium.
[12] The present invention provides the radioactive substance contamination prevention method according to [11], wherein the clay fine particles are at least one of bentonite and zeolite.
[13] The radioactivity according to [11] or [12], wherein the suspension having the clay fine particles is an aqueous solution containing 0.05 to 5% by mass of the clay fine particles. Provide a method to prevent the spread of contamination of substances.
[14] The present invention disperses radioactive cesium in the clay fine particles by spraying a suspension having clay fine particles and the soil solidifying agent described in [6] in this order on soil contaminated with radioactive cesium. Decontamination of contaminated soil, wherein at least a part of the soil is solidified by the soil solidifying agent after the soil containing the clay fine particles incorporated with the radioactive cesium is solidified. Provide a method.
[15] The present invention provides the decontamination method for contaminated soil according to [14], wherein the clay fine particles are at least one of bentonite and zeolite.
[16] The contamination according to [14] or [15], wherein the suspension having the clay fine particles is an aqueous solution containing 0.05 to 5% by mass of the clay fine particles. Provide a method for decontamination of soil.
[17] The present invention is characterized in that the soil of the construction surface is created and greened by spraying the soil solidifying agent according to [6] onto the soil of the construction surface and solidifying the surface layer of the soil. Provide a vegetation foundation creation method.
[18] In the present invention, water purification is performed by mixing the coagulating precipitation agent according to [7] or [8] above in contaminated water or waste water, and precipitating charged floating particles contained in the contaminated water or waste water. A water purification method is provided.

  The dispersive polymer flocculant composed of an aqueous solution containing either the cationic polymer or the anionic polymer of the present invention is stable and uniform for a long period of time without forming a precipitate even in a state where no excess salt is contained. Since it forms a colloidal water solution, it can be used as a one-part polymer flocculant aqueous solution, so that it is easy to handle. In addition, a large cohesive force is obtained when added to soil, domestic wastewater, industrial wastewater, etc., so that a soil solidifying agent capable of effective soil solidification, and a coagulating precipitant that can also be applied to efficient water purification Can be used respectively. Furthermore, since the dispersive polymer flocculant of the present invention can be used in a state in which the content of a salt that may inhibit plant growth is reduced, it can be used when applied as a soil solidifying agent and an aggregating precipitant. The load on the environment can be reduced.

  By applying the soil solidifying agent according to the present invention to the method for preventing the spread of radioactive material contamination, the decontamination method for contaminated soil, and the vegetation base construction method, effective soil solidification can be performed without inhibiting plant growth. Soil greening or agricultural product growth after treatment or creation can be performed naturally without labor and economic burden. Moreover, by applying the coagulating precipitant according to the present invention to the water purification method for domestic wastewater and industrial wastewater, not only can efficient treatment be performed, but also changes in the ion concentration and pH of the purified water can be suppressed as much as possible. Therefore, a safer water purification system can be constructed.

It is a schematic diagram which shows an example of the form which the dispersion type polymer flocculent of this invention has in aqueous solution. It is a figure which shows the process of the contamination expansion prevention method of the radioactive substance using the soil fixing agent of this invention. It is a figure which shows the process of the decontamination method of the contaminated soil using the soil fixing agent of this invention. It is a figure which shows an example of the relationship between the charge ratio of an anionic polymer and a cationic polymer, and the property which the aqueous solution containing those polymers has. It is a figure which shows the experimental method for measuring soil fixed intensity | strength in this invention. It is a figure which shows the soil fixed intensity | strength of the soil solidified with the dispersion type polymer flocculent of this invention which adjusted the anionic polymer (CMC) excessively with the charge ratio. It is a figure which shows the soil fixed intensity | strength of the soil solidified with the dispersion type polymer flocculent of this invention which adjusted the cationic polymer (PDADMAC) excessively with the charge ratio. In Example 1 of this invention, it is a figure which shows the relationship between soil fixed strength and soil fixed thickness, and a polymer concentration. It is a figure which shows the dust amount measuring method of the soil in this invention. It is a figure which shows the dust amount change accompanying the elapsed time of the soil solidified using the dispersion type polymer flocculent of Example 1 and 5 of this invention. It is a figure which shows the relationship between the amount of dust after 200 hours progress of the soil solidified using the dispersion-type polymer flocculent of Example 5 of this invention, and a polymer concentration. It is a figure which shows the relationship between the amount of dust after 200 hours progress of the soil solidified using Example 1 of this invention, and polymer concentration. It is a figure which shows the germination rate measuring method of the seed | species in this invention. It is a figure which shows another example of the relationship between the charge ratio of an anionic polymer and a cationic polymer, and the property which the aqueous solution containing those polymers has. It is a figure which shows the soil fixed intensity | strength of the soil solidified using the dispersion type polymer flocculent of this invention which adjusted the anionic polymer (PAANA) excessively with the charge ratio. It is a figure which shows the soil fixed intensity | strength of the soil solidified using the dispersion type polymer flocculent of this invention which adjusted the cationic polymer (PDADMAC) excessively with the charge ratio. It is a figure which shows the relationship between the fixed thickness of a soil, and a polymer concentration about another dispersion type polymer flocculent of this invention. It is a figure which shows the dust amount change accompanying the elapsed time of the soil solidified using the dispersion type polymer flocculent of Example 9 and 13 of this invention. It is a figure which shows the relationship between the amount of dust after 200 hours progress of the soil solidified using the dispersion type polymer flocculant of Example 9 of this invention, and a polymer concentration. It is a figure which shows the relationship between the amount of dust after 200 hours progress of the soil solidified using the dispersion-type polymer flocculent of Example 13 of this invention, and polymer concentration. It is a figure which shows the relationship between the turbidity of the supernatant liquid of a bentonite suspension, and the total amount of the ionic polymer contained in the coagulation precipitation agent.

  In the dispersion type polymer flocculant of the present invention, in an aqueous solution containing a cationic polymer and an anionic polymer, one of the polymers is the first polymer and the other polymer is the second polymer. When the first polymer is blended in excess at a charge ratio compared to the second polymer, it maintains a large cohesive force and is stable and stable for a long time without generating a precipitate. It has been made by finding that a colloidal water solution can be formed.

  FIG. 1 is a schematic diagram of a form of a dispersion polymer flocculant of the present invention in which a cationic polymer is excessively adjusted with a charge ratio in an aqueous solution, and one embodiment of the dispersion polymer flocculant of the present invention It is. As shown in FIG. 1, the dispersive polymer flocculant of the present invention contains both a cationic polymer and an anionic polymer, thereby causing entanglement of molecular chains and serving as a nucleus for generating a large cohesive force. A hydrophobic floc is formed. On the other hand, since either one of the cationic polymer or anionic polymer is excessively contained, the formation of precipitates is suppressed by the presence of hydrophilic molecular chains with increased affinity with water. And uniformly dispersed. Accordingly, the aqueous solution has an opaque or milky white property, and has a great feature in that a uniform solution that is stable for a long period of time can be formed without forming a precipitate.

  Here, “opaque or milky white” is determined by visual observation. For example, when the dispersed polymer flocculant of the present invention is placed in a 2 mm thick glass plate, characters on the other side of the glass plate are clear. It has an opacity level that cannot be distinguished. When measuring as light transmittance, it becomes a standard to have less than 85% with the same thickness. In order to achieve the effect of the present invention, it is a necessary condition that the precipitate is not observed even if it is left for 24 hours or more in summer and winter (temperature range: 5 to 30 ° C.).

  The colloidal aqueous solution used in the present invention does not have an equal charge ratio of the addition amount of the cationic polymer and the anionic polymer, but by adding either one so that the charge ratio is excessive, Since the formation can be suppressed, it is not necessary to actively add a salt essential for obtaining a one-component polyion complex to the colloidal aqueous solution as in the prior art. However, the ionic polymer originally contains a trace amount of counter ions, and the colloidal aqueous solution used in the present invention may contain a substantially trace amount of salt. The salt for forming a counter ion and the salt positively added to the colloidal aqueous solution of the present invention differ depending on the type of ionic polymer used, but in general, sodium chloride, potassium chloride, ammonium chloride At least one salt selected from magnesium chloride, sodium sulfate, potassium sulfate, ammonium sulfate, magnesium sulfate, sodium nitrate, potassium nitrate, and ammonium nitrate is used. The salt added positively to the colloidal aqueous solution of the present invention functions to buffer the electrostatic force of the zwitterionic polymer.

  In the cationic and anionic zwitterionic polymers used in the present invention, the charge ratio of both ionic polymers is defined as follows by the “ion equivalent mass” of the ionic polymer. Is.

The molecular weight of either one of the ionic polymers (A) used in the present invention is M ₁ , and the ion equivalent mass is EW ₁ . The ion equivalent mass (EW ₁ ) of the ionic polymer ( _A ) is the same as the molecular weight (m _A ) of the structural unit having an ion when the proportion of the structural unit having the ion is 100 mol%. For example, when the proportion of structural units having ions is 50 mol% and the proportion of structural units having no ions is 50 mol%, the ion equivalent mass has the molecular weight (m _A ) of the structural units having ions and ions. It becomes the sum (m _A + m _N ) with the molecular weight (m _N ) of the structural unit that does not. Thus, the ion equivalent mass is determined by the molar ratio between the structural unit having ions and the structural unit not having ions. In the case of the other ionic polymer (B), when the molecular weight of the ionic polymer (B) is M ₂ and the ion equivalent mass is EW ₂ , the ion equivalent mass is obtained in the same manner.

The amount of one of the ionic polymer in the ionic polymer contained in the colloidal solution of the present invention (A) and C _1, the other the amount of the ionic polymer (B) C ₂ . In this case, the colloidal solution contains the ionic polymer (A) at a concentration of (C ₁ / M ₁ ) mol and the ionic polymer (B) at a concentration of (C ₂ / M ₂ ) mol. Therefore, in the colloid solution, the number of charges due to each ion contained in the ionic polymer (A) and the ionic polymer (B) is P ₁ (equivalent) = (C ₁ / M ₁ ) × (M ₁ ), respectively. / EW ₁ ) and P ₂ (equivalent) = (C ₂ / M ₂ ) × (M ₂ / EW ₂ ).

If P ₁ = P ₂ (total charge is zero), C ₁ / EW ₁ = C ₂ / EW ₂ . On the other hand, when the total charge of the colloidal aqueous solution is not zero, P ₁ / P ₂ = (C ₁ / EW ₁ ) / (C 2 / EW ₂ )> 1 and (C ₁ / EW ₁ ) / (C ₂ / EW ₂ ) The relationship of> 1 is satisfied. P ₁ and P ₂ are not specified as either an anionic polymer or a cationic polymer, and may be reversed. Therefore, in the present invention, by mixing the anionic polymer and the cationic polymer so as to satisfy the relationship of (C ₁ / EW ₁ ) / (C ₂ / EW ₂ )> 1, one of the ions It is possible to prepare an aqueous colloidal solution in which a functional polymer is excessively added at a charge ratio.

  The inventors of the present invention analyzed the concentrations of the anion and cation, which are counterions of the cationic polymer and anionic hawk, respectively, in the aqueous colloid used in the present invention. As a result, when a new salt is not actively added to the colloidal solution, the total ion content of both ions is relative to the weight of the total colloidal solution when the anion and cation are individual ions. And found to be less than 2.5% by mass. Furthermore, when the total concentration of ions when the salt is actively added to the colloidal solution of the present invention later is less than 1.5% by mass with respect to the weight of the total colloidal solution, excluding the concentration of counterions In addition, the dispersed polymer flocculant of the present invention that can reduce the burden on the environment without inhibiting the growth of plants can be obtained. The lower the total concentration of newly added salt, the better, and preferably less than 0.5% by weight. Therefore, the dispersion type polymer flocculant of the present invention needs to have a total content of cations and anions of at least less than 4.0% by mass when the total amount of the aqueous colloidal solution is 100 parts by mass. Yes, preferably less than 3.0% by weight. The colloid solution of the present invention may be used by adding a salt in addition to the counter ion of the ionic polymer as long as the total content of cations and anions is less than 4.0% by mass. . In this case, the addition amount of the cationic polymer and the anionic polymer can be blended close to the equal charge ratio, so that an improvement in cohesion as a polymer coagulant can be expected.

  The primary purpose of the dispersed polymer flocculant of the present invention is to reduce the environmental load as much as possible, and in order to minimize the concentration of ions contained in the aqueous colloidal solution, an extra component other than the counter ion is used. It is preferable not to add new salt. In that case, in order to suppress the formation of precipitates, the optimum amount of addition of the cationic polymer and the anionic polymer is far from the equicharge ratio. In the dispersion type polymer flocculant of the present invention, the first polymer needs to be blended with the second polymer in an excess of 2 times or more in charge ratio. If the charge ratio is 2 times or more, the uniformity and stability of the colloidal aqueous solution can be maintained for a long time. The charge ratio of the two changes depending on the type of the cationic polymer and the anionic polymer, and the larger the difference between the ratios, the smaller the risk of forming a precipitate, but on the other hand, there is a slight decrease in cohesive force. It can be seen. Therefore, the charge ratio of the first polymer to the second polymer can be selected from the viewpoint of the uniformity and stability of the colloid solution and the cohesive force after the colloid solution is sprayed.

  In the present invention, the upper limit of the blending amount when the first polymer is excessively blended with the second polymer in a charge ratio is a translucent or milky white color in which the colloidal aqueous solution does not form a precipitate. It is preferable that it is the compounding quantity until a uniform state can be maintained. At the charge ratio at which the aqueous colloidal solution becomes transparent, the stability of the aqueous solution is greatly improved, but the cohesive force is almost the same as the aqueous solution containing only one of the cationic polymer and the anionic polymer, and the soil solidifying agent. Or it is because the functional fall as a coagulating precipitation agent becomes remarkable. As a specific blending ratio, the upper limit of the blending amount of the first polymer with respect to the second polymer is 80 times in charge ratio, and preferably 70 times.

  The dispersion-type polymer flocculant of the present invention is at least one selected from cationic cellulose, cationic starch, a polymer having an amino group, or a polymer of a quaternary ammonium salt as a cationic polymer, The anionic polymer includes at least one selected from carboxymethyl cellulose, carboxymethyl amylose, lignin sulfonic acid and its salt, polyacrylic acid and its salt, polysulfonic acid and its salt. In the present invention, it is not necessary to newly add a salt for buffering the electrostatic force of the zwitterionic polymer. However, if necessary, the salt is constituted when the total amount of the colloidal aqueous solution is 100 parts by mass. A small amount of salt may be added within the total concentration of ions including the cations and anions to be added is less than 1.5% by mass.

  The dispersion type polymer flocculant of the present invention is in the form of an aqueous solution, and the other components other than the ionic polymer and / or the salt that are cationic and anionic are water, but an aqueous medium containing water as a main component. May be used. The aqueous medium mainly composed of water used in the present invention is a medium in which water accounts for 80% by mass or more, preferably 90% by mass or more, and more preferably 95% by mass or more. In addition to water, for example, water-soluble alcohols such as methyl alcohol, ethyl alcohol, and 2-propanol, ethers such as diethyl ether and tetrahydrofuran, or ketones such as acetone, methyl ethyl ketone, and cyclohexanone are used in a small amount. May be. These solvents adjust the viscosity with respect to the aqueous solution of the dispersion type polymer flocculant of the present invention or, if necessary, other components other than the ionic polymer and / or the salt composed of cationic and anionic properties. It is used when it is necessary to dissolve these components when used in combination. Among these solvents, ethyl alcohol is preferable in order to reduce the influence on the human body and the environmental load.

  Next, the soil fixing agent using the dispersed polymer flocculant of the present invention will be described.

[Soil fixing agent]
When the dispersive polymer flocculant of the present invention is used as a soil fixing agent, 0.5 g of the polymer obtained by combining the cationic polymer and the anionic polymer in a mass of 100 ml of the colloidal aqueous solution is used. A colloidal aqueous solution containing more than [0.5% (w / v = mass / volume)] and 10 g [10% (w / v = mass / volume)] or less is used. Since the desired cohesive force can be obtained as a soil solidifying agent when the content of the polymer combining the cationic polymer and the anionic polymer exceeds 0.5% (w / v), It can be reduced and is suitable for simple processing. Moreover, it becomes easy to adjust the width and thickness of the soil continuous layer after the soil is fixed, and it becomes possible to fix the soil having a thickness of several centimeters. If this content is 10% (w / v) or less, the viscosity of the colloidal aqueous solution can be prevented from significantly increasing, so that not only the spraying and handling properties of the liquid are improved, but also the permeability to the soil is increased. be able to. In addition, since the concentration of cations and anions contained in the liquid can be set low, the burden on the environment can be reduced. When the content exceeds 10% (w / v), a precipitate may be generated when the colloidal aqueous solution is stored for a long period of time, and the problem of difficulty in managing and adjusting the liquid tends to occur. Furthermore, the permeability to the soil is remarkably lowered, the thickness of the soil that can be fixed is restricted, and the soil cannot be fixed efficiently.

  The soil solidifying agent of the present invention can be applied to various uses. Therefore, as a specific application example, a method for preventing contamination of radioactive substances, a decontamination method for contaminated soil, and a method for creating a vegetation substrate will be described below.

[Method of preventing the spread of radioactive material contamination by soil solidifying agents]
When the soil solidifying agent of the present invention is applied as a method for preventing the spread of radioactive substance contamination, the colloid aqueous solution contains a polymer content of the cationic polymer and the anionic polymer in 100 ml of the colloid aqueous solution. On the other hand, not only is it specified to exceed 0.5% (w / v) but not more than 10% (w / v) by mass, and the viscosity at 4 to 30 ° C. is adjusted to the range of 0.1 to 100 mPa · s. Is preferred.

  The soil fixing construction work is carried out in an external environment of 4 to 30 ° C. throughout the year, and this viscosity range is determined from the workability by coating and impregnation and the thickness of the continuous layer of fixed soil formed after drying. . In addition, radioactive substances such as cesium are localized within a few centimeters in the depth direction from the soil surface, and if a continuous layer composed of contaminated soil fixed with the soil fixing agent of the present invention can be formed to a thickness within several centimeters, It can sufficiently fulfill the function of preventing the spread of radioactive material contamination. In the present invention, if the viscosity of the soil solidifying agent is 0.1 mPa · s or more, a thick continuous layer of fixed soil formed after drying is secured while ensuring applicability and permeability of the soil fixing agent. It is possible to achieve a great suppression effect on the expansion of radioactive material contamination. Further, since the contaminated soil is formed as a continuous layer that is firmly fixed, it is possible to prevent the occurrence of breakage and cracks and to prevent the diffusion of radioactive substances to the outside. In addition, if the viscosity is 100 mPa · s or less, the operability and workability of the soil fixative can be prevented from being significantly reduced and the permeability to soil can be maintained. A thick continuous layer of soil can be formed, and many radioactive materials can be confined in thick contaminated soil. Thereby, it is possible to effectively prevent the spread of contamination.

  According to the method for preventing contamination of radioactive substances of the present invention, the suspension of radioactive fine particles and the soil solidifying agent of the present invention are sprayed in this order on the soil contaminated with radioactive cesium, whereby radioactive cesium is dispersed in the clay fine particles. It is preferable to solidify the soil containing the clay fine particles taken in and incorporating the radioactive cesium. Thereby, the effect of preventing the spread of contamination can be enhanced. The clay fine particles are an effective component for selectively adsorbing radioactive substances and suppressing leakage and scattering of radioactive substances that are likely to occur during and after soil fixation treatment.

  Examples of the clay fine particles include inorganic particles having an adsorbing ability for adsorbing radioactive substances, such as bentonite, zeolite, mica, vermiculite, and smectite. Although the average particle diameter of these inorganic particles can be in the range of 0.01 to 20 μm, it is preferably 1 to 2 μm. The maximum particle size of these inorganic particles is 100 μm or less, preferably 50 μm or less. When the average particle size is less than 0.01 μm, the aggregation of inorganic particles is likely to occur, and the workability in the adjustment and application of the radioactive decontamination solution becomes remarkable. On the other hand, when the thickness exceeds 20 μm, inorganic particles having a large diameter are mixed in the continuous layer, so that the mechanical strength of the continuous layer is greatly reduced and peeling becomes difficult. Furthermore, decontamination of radioactive substances adhering to fine grooves and steps existing on the surface of the structure cannot be reliably performed, and a decontamination residue is likely to occur. For the same reason, the maximum particle size of these inorganic particles is 100 μm or less, preferably 50 μm or less.

  In the present invention, among the above inorganic particles, bentonite and zeolite are preferable from the viewpoint of achievement as a radioactive material adsorbent, handleability, low cost, and the like. Among them, when bentonite is dried, when the soil fixing agent dries, the effect of absorbing surrounding moisture at the time of drying, the so-called sanction effect, is superior to other inorganic particles, so that radioactive materials are not released outside. It is particularly useful. Bentonite can be obtained at a low cost because it can be used as it is after adjusting the maximum particle size to 100 μm or less, preferably 50 μm or less by removing coarse particles from those mined in the bentonite mine.

  In the suspension having clay fine particles used in the present invention, the content of the clay fine particles is more preferably 0.05 to 5% by mass, further 0.5%, when the suspension is 100 parts by mass. -3 mass% is particularly preferred. When the content of the clay fine particles is 0.05% by mass or more, a sufficient adsorption effect of the radioactive substance is obtained, and the radioactive substance trapping ability prevents leakage and scattering of the radioactive substance during the decontamination process and long-term storage. Can be avoided. Further, when the content of the clay fine particles is 5% by mass or less, not only a sufficient adsorption effect of radioactive substances can be obtained, but also a rapid increase in the viscosity of the suspension itself can be suppressed. It is possible to prevent a significant decrease in workability and workability. Since the clay fine particles are inorganic, segregation in the suspension is more likely to occur as the content thereof increases, and not only the handling property is deteriorated, but also the cause of generation of discrete, fractured or cracked soil fixed layers. Therefore, it is preferable to set the upper limit value. As described above, bentonite is suitable as the clay fine particles in the present invention, but bentonite is often used as a thickener or a waterstop material. Therefore, when bentonite is used together with the soil fixing agent of the present invention, if its content increases, the viscosity increases rapidly and the coating workability is greatly reduced, so the content of bentonite in the suspension Is 5% by mass or less, and on the other hand, the lower limit is preferably 0.05% by mass in order to reliably adsorb the radioactive substance by bentonite.

  Next, the process of the radioactive substance contamination expansion preventing method using the soil solidifying agent of the present invention will be described with reference to FIG.

(S1) Adjustment of soil solidifying agent:
Based on the blending ratio as described above, an aqueous solution containing a cationic polymer and an anionic polymer is prepared, and the ionic polymer is combined with the cationic polymer and the anionic polymer in water. The soil solidifying agent of the present invention in which the molecular content is defined within the range of the charge ratio as described above is prepared. Moreover, in order to perform application | coating or dispersion | spreading easily and reliably, adjustment of the viscosity of the aqueous solution of a soil solidifying agent is also performed. No new salt is added to the soil solidifying agent used here, but if necessary, the total concentration of ions including the cations and anions contained in the soil solidifying agent is less than 4.0% by mass. You may add a new salt in the range of less than 1.5 mass%. In addition to the cationic polymer and the anionic polymer and / or salt component, if necessary, polymer adhesive, plasticizer, dispersant, surfactant, thickener, viscosity adjustment An agent, an antiseptic, a colorant, a deodorant, or the like can be blended.

(S2) Application or application of soil solidifying agent to contaminated soil:
The soil solidifying agent adjusted in the above (S1) is sprayed or applied to the soil to which the radioactive substance is attached at room temperature (a range of 4 to 30 ° C. throughout the year). Spraying or application is carried out by spraying, pouring or brushing depending on the location of the contaminated soil and the form of installation, but spraying by spraying etc. is generally used for wide-area decontamination Is done. Moreover, in dispersion | spreading or application | coating, the soil solidifying agent of this invention can be heated previously and viscosity can be adjusted. Furthermore, you may use the coating device or spray apparatus which can be heated at the time of dispersion | spreading or application | coating.

(S3) Drying:
After the step (S2), the soil solidifying agent of the present invention is dried to evaporate water or an aqueous medium. Drying is performed at an outside air temperature for a predetermined time (usually 1 hour to 1 week), but if necessary, a method of adding hot air to an application or spraying place to accelerate drying may be employed. In the present invention, usually, if the drying time is 2 to 3 days, the peeling can be performed, and if the temperature is high, the peeling operation can be started in the shortest day.

(S4) Formation of a continuous layer composed of contaminated soil fixed with a soil solidifying agent:
After drying the soil solidification solution of the present invention, a continuous layer consisting of contaminated soil fixed by the ionic polymer is formed on and near the soil surface. The thickness of the continuous layer is in the range of several mm to 100 mm, and is usually formed with several tens of mm.

(S5) Dispersion or application of suspension having fine clay particles to contaminated soil:
This step of spraying or applying the suspension having clay fine particles is most effective when performed before the step (S2) as shown in FIG. This is because the clay particles need to be brought into direct contact with the soil containing the radioactive material as much as possible in order to promote selective adsorption and capture of the radioactive material by the clay particles. After this step, the soil containing clay particles is solidified by passing through the steps (S2) to (S4) before the soil containing clay particles is completely dried. Leakage and scattering can be suppressed. At this time, if necessary, after this step, after introducing a drying step using long-term standing or hot air to dry the soil almost completely, spraying of the soil solidifying agent in the step (S2) Or you may apply | coat. In the present step, spraying or coating is performed by a spraying method, a pouring method, a brush coating method, or the like according to the location of the contaminated soil and the installation form, as in the case of the step (S2). In the method for preventing the spread of contamination according to the present invention, since the effect of supplementing and taking in radioactive substances such as radioactive cesium is high, it is preferable to use a suspension having the clay fine particles together with the soil solidifying agent of the present invention.

  As described above, the method for preventing contamination of radioactive substances according to the present invention can be confined in a continuous layer of soil in which radioactive substances such as cesium are immobilized. The method for preventing the spread of contamination according to the present invention can be applied not only to flat soils such as residential areas and fields, but also to forests and forests where decontamination is difficult. When applied to mountain forests and the like, it is possible to leave them in a state in which radioactive materials such as cesium are prevented from scattering or diffusing without removing contaminated soil or fallen leaves. Therefore, it can be left for a long time until there is no adverse effect on the human body due to radioactive substances such as cesium, and it is not necessary to remove or remove contaminated soil, fallen leaves or trees. Furthermore, since the growth of the plant is hardly inhibited, an effect that the load on the environment can be extremely reduced can be obtained. Thus, the contamination expansion preventing method according to the present invention can be regarded as one of effective decontamination methods for radioactive substances.

[Decontamination method of contaminated soil with soil solidifying agent]
The process of the decontamination method for contaminated soil using the soil solidifying agent of the present invention will be described with reference to FIG. As shown in FIG. 3, the decontamination method of contaminated soil by this invention forms the continuous layer which consists of contaminated soil through the same process as the process of (S1)-(S5) shown in FIG. Thereafter, the following steps (S6) to (S9) are added, and decontamination is performed by peeling or removing the contaminated soil. Here, when the soil solidifying agent of the present invention is applied as a decontamination method for contaminated soil of radioactive substances, the cationic polymer and the anionic high concentration in the colloidal aqueous solution are the same as the method for preventing the spread of contamination. Not only to regulate the content of the polymer combined with the molecule to 0.5 to 10% (w / v), but also to adjust the viscosity at 4 to 30 ° C. to the range of 0.1 to 100 mPa · s. preferable.

(S6) Separation and removal of continuous layer consisting of contaminated soil fixed with soil solidifying agent:
The continuous layer composed of contaminated soil fixed with the soil solidifying agent of the present invention is peeled off manually or using a peeling device. Since the continuous layer is a thin film, it can be easily peeled off. The peeling device may be a device that, after fixing one surface of the continuous layer, performs a peeling operation while slowly moving the fixed surface or fixed point as a starting point. In this invention, since the said peeling layer has the intensity | strength and moderate elasticity which can fully endure peeling, it is excellent in operativity and workability | operativity. Moreover, you may peel as needed, applying hot air or cold wind to the peeling part of the said continuous layer. Hot air is used to volatilize water or an aqueous medium or to give flexibility to the continuous layer. On the contrary, the cold wind is used to increase the strength at the time of peeling by slightly hardening the continuous layer.

(S7) Storage / preservation of continuous layer consisting of contaminated soil fixed with soil solidifying agent:
After peeling and removing in the step (S6) above, the continuous layer made of contaminated soil fixed with a soil solidifying agent contains radioactive substances such as cesium. Therefore, measures should be taken to prevent the radioactive substances from scattering or leaking outside. They are collected and stored at the place where they are given. Eventually, it is stored and preserved in a sealed state until it is confirmed that the radiation dose has been reduced to a level that does not affect the human body at all, and then returned to normal soil or discarded as industrial waste.

(S8) Sifting or classification of contaminated soil fixed with soil solidifying agent:
This step is performed in order to reduce the volume of the contaminated soil, and the following two methods can be employed. As a first method, after the contaminated soil peeled and removed in the step (S6) is sufficiently dried and solidified, the solidified contaminated soil is screened and selected. In the sieving, only a solidified soil portion is selected and removed using a metal sieve such as aluminum having a predetermined mesh diameter. In this first method, the non-solidified soil that has fallen off the sieve is returned to its original location and reused, and only the solidified large-grain soil mass remaining on the sieve is stored or preserved. In the present invention, when the step (S5) is introduced, the effect of adsorbing and capturing radioactive substances such as cesium by the clay fine particles such as zeolite and bentonite contained in the contaminated soil together with the soil solidifying agent of the present invention is obtained. For this reason, most of the radioactive substance remains in a lump of solidified soil having a large particle size. On the other hand, the non-solidified soil that has fallen from the sieve has a very high removal rate of radioactive material of about 80% or more. In this way, in the step (S9) to be described later, only a large particle size soil mass can be stored and stored in another place, and the volume of the contaminated soil can be reduced. Therefore, the 1st method implemented in order to implement | achieve volume reduction of the said contaminated soil can acquire a big effect by introduce | transducing the process of said (S5).

  As described in Patent Document 5, the second method for reducing the volume of the contaminated soil is “as much of radioactive cesium is strongly adsorbed and immobilized on clay particulate components. Based on the idea that, while washing coarse particles, only fine particles are classified and collected, and only fine particle components containing radioactive cesium are treated as radioactive waste soil, the contaminated soil is classified in the presence of water, It is to be washed. In the second method, the contaminated soil treated only with the soil solidifying agent of the present invention is used without introducing the step (S5), and the contamination is performed after the step (S6) or (S7). Collect soil, classify and wash with water. Since the classification / washing step is performed using water, the collected contaminated soil does not need to be sufficiently dried and solidified. For example, after applying or spraying the soil solidifying agent to the contaminated soil in the step (S2), the contaminated soil may be collected without being sufficiently dried, and classified and washed as it is. . The classification performed in the second method is usually performed with a classification size of less than 0.1 mm, but an optimum classification size can be set according to the geology of the decontamination area and the decontamination rate of the radioactive material. The soil other than the fine particle component of the clay selected with the classification size of less than 0.1 mm has a very small content of radioactive substances, so after examining the radiation dose and confirming the radiation dose, You can return to the place. If the radiation dose does not fall below the allowable value, repeat the classification and washing process of this process, or leave it for a predetermined period and confirm that the radiation dose has been reduced, then return to normal soil Or as industrial waste.

(S9) Storage / preservation of large-particle-size soil lump after sieving or clay particulate component after classification:
In the step (S8), only the large-diameter soil lump screened by the first method is transferred to another place and stored and stored. Similarly, the clayey fine particle components classified by the second method and selected are stored and stored in an isolated state.

  As described above, the method for decontamination of contaminated soil using the soil solidifying agent of the present invention is intended to reduce radiation quickly, efficiently and effectively from soil to which radioactive material is attached or soil containing radioactive material. In order to store and preserve the radioactive material-contaminated soil in a sealed state by the steps (S1) to (S7) shown in FIG. 3 and further reduce the volume of the radioactive material-contaminated soil itself (S1) to FIG. It is preferable to perform the treatment by the step (S9).

[Vegetation foundation creation method with soil solidifying agent]
As another soil immobilization method to which the soil solidifying agent of the present invention is applied, a vegetation base construction method will be described.

  For vegetation foundation creation, vegetation foundation materials are sprayed on the bare slopes (directions) generated by civil engineering and natural disasters, etc. for the purpose of environmental conservation, collapse prevention, landscape restoration, etc., in order to fix and green the soil. Has been done. In addition, a green soil base with a thick soil layer that can grow plants by spraying greening base material, etc. on the surface and flat ground where the plant is difficult to grow on rocks, soft rocks with little soil, sandy land, etc. However, it has also been adopted as a method for growing plants and planting trees within the base.

  As the vegetation base material or the greening base material, a soil solidifying agent is conventionally used as a flocculant in addition to soil components and water. The soil component is used as a guest soil material, and the guest soil material is mixed with an aggregation promoting material such as peat moss, bark compost, organic fiber or clay, Greening materials such as fertilizers or seeds may be blended. The flocculant added to the vegetation base material or the greening base material is either a cationic flocculant or an anionic flocculant alone or in combination with a nonionic flocculant. When both a cationic flocculant and an anionic flocculant are used, as disclosed in Patent Document 2, each component prepared by dividing it into two tanks is used for blowing by a two-component sprayer. A method of forming a gel structure by attaching is adopted.

  The soil solidifying agent of the present invention, as a flocculant to be added to the vegetation base material or the greening base material, in place of the conventional flocculant, either a cationic polymer or an anionic polymer is excessive in the aqueous solution. In addition to suppressing the formation of precipitates due to the formation of a gel structure, the uniform stability of the aqueous solution is increased, and the cohesive strength of the soil is enhanced using the gelation reaction promoted by the coexistence of both ionic polymers. It is to improve. Furthermore, since the salt concentration contained in the water solution can be greatly reduced as compared with the conventional polyion complex solution, there is almost no adverse effect such as inhibiting the growth of plants. In addition, the soil solidifying agent of the present invention is further used in combination with a highly water-retentive bentonite known as a thickener or water-stopping material as a clay component, thereby further enhancing the function of soil solidification by a vegetation base material or a greening base material. Can be increased.

  The soil solidifying agent of the present invention is a vegetation base by mixing it with at least one kind of water-containing material including soil components, agglomeration promoting material, tree planting material, erosion inhibitor and metal inorganic salt, and water. It can be used as a timber or a greening base material. In addition, after building using a vegetation base material or a greening base material mixed with at least one of secondary materials such as agglomeration promoting materials, greening materials, erosion inhibitors and metal inorganic salts, and water Application of the aqueous solution, which is the soil solidifying agent of the present invention, by spraying or pouring the formation site or the like by spraying or the like may be carried out, and the soil may be solidified by drying. The area of the creation place before spraying or applying the soil solidifying agent of the present invention can be arbitrarily set according to the solidified state of the soil. In the case where it is desired to quickly solidify the soil at the site where the vegetation base material or the greening base material is used, the soil solidifying agent of the present invention is sprayed or applied at the same time, or immediately after the creation work.

  As described above, by applying the soil solidifying agent of the present invention as a flocculant component of a vegetation base material or a greening base material, it is possible not only to facilitate the construction work by simple processing, but also to aggregate the guest soil material It is possible to simultaneously solidify the soil by promoting the conversion and to plant the environment-friendly soil that does not inhibit the germination and growth of the plant.

[Aggregating precipitant]
The dispersive polymer flocculant of the present invention can be applied not only as the above-mentioned soil solidifying agent but also as a flocculant precipitant applied to water purification methods for domestic wastewater and industrial wastewater. Although the object of water purification is not particularly limited, it can be used not only for agglomerating and removing charged suspended particles in sewage, human waste and industrial wastewater, but also for various wastewater or wastewater containing sludge. . For example, domestic wastewater treatment sludge, food factory wastewater treatment sludge, chemical factory wastewater treatment sludge, pig farm wastewater treatment sludge, pulp or paper mill sludge, mixed sludge containing organic sludge generated in general industrial wastewater and coagulated sedimentation sludge, etc. Is possible.

  When the dispersion-type polymer flocculant of the present invention is used as a coagulation-precipitating agent, a polymer obtained by combining the cationic polymer and the anionic polymer in a mass of 0.1 g to 100 ml of the colloidal aqueous solution. A colloidal aqueous solution containing 10 g is used. Cohesive force sufficient to precipitate charged floating particles contained in contaminated water or waste water when the content of the polymer of the cationic polymer and the anionic polymer is 0.1% (w / v) or more. Is obtained. If the charged floating particles increase due to increased contamination or contamination of contaminated water or wastewater, increase the content of the ionic polymer or use the dispersed polymer flocculant of the present invention. Increase the number of times to purify water. On the other hand, if the content of the polymer including the cationic polymer and the anionic polymer is less than 0.1% (w / v), contamination may occur even if the number of times the dispersed polymer flocculant is added is increased. Since it is immediately diluted by water or waste water, the desired cohesive strength cannot be obtained. In addition, when the content is 10% (w / v) or less, a significant increase in the viscosity of the aqueous colloidal solution can be suppressed. Can be easily mixed and efficient water purification can be performed. When this content exceeds 10% (w / v), as in the case of the soil solidifying agent, a precipitate may be formed when the colloidal aqueous solution is stored for a long period of time. Becomes difficult. Furthermore, since the produced precipitates are often saturated with agglomeration effect, the effect of aggregating the charged floating particles is small. As described above, the colloidal aqueous solution used as the coagulating precipitant of the present invention needs to have the colloidal particles uniformly dispersed without forming a precipitate in order to maintain the cohesive force.

  In addition, when the dispersion type polymer flocculant of the present invention is applied as an aggregating and precipitating agent, not only as the aqueous solution, but also a solid obtained as a residue after removing water from the aqueous solution or the solid is pulverized. It can be used in the form of a powdery body obtained. As shown in FIG. 1, the cationic polymer and the anionic polymer contained in the dispersion type polymer flocculant of the present invention are entangled in molecular chains that form a hydrophobic floc serving as a nucleus for generating a large cohesive force. And a complex form with molecular chains that have an affinity for water. Therefore, only when water is removed while maintaining its form, not only uniform dispersibility in contaminated water or wastewater but also a large cohesive force is obtained for the charged floating particles. It is difficult to obtain such an effect simply by mixing a solid cationic polymer and a solid anionic polymer in a predetermined amount. The solid or powdery aggregation precipitant obtained in the present invention is produced by paying attention to this point.

  In addition to using the solid or powdery coagulating precipitant obtained in the present invention alone, it is used by adhering to the surface of a plastic non-woven fabric or fiber made of rice husk, polyvinyl alcohol (PVA) or the like. can do. Here, the rice husk and the plastic nonwoven fabric or fiber functioned as a carrier for the solid or powdery aggregated precipitant, and thus did not function as a coagulant for the charged floating particles during the water purification treatment. Even if there is something, it is still supported as it is, and it is possible to reuse or effectively utilize the flocculant of the present invention.

  The aqueous solution of the coagulating precipitation agent of the present invention used in the water purification method or a solid or powder thereof is either a cationic polymer coagulant or an anionic polymer coagulant alone, or any one of them and highly nonionic. Compared with the conventional coagulating precipitant used in combination with the molecular coagulant, a large cohesive force is obtained for the charged floating particles contained in the waste water or wastewater, and the effect of enlarging the coagulated particles is increased. This is thought to be due to the presence of hydrophobic flocs formed by entanglement of molecular chains as shown in FIG. Furthermore, it has been found that the coagulating precipitation agent of the present invention has the following characteristics.

  Conventional coagulant-precipitating agents generally have a narrow allowable range for the amount added when coagulating and precipitating the charged floating particles present in contaminated water or waste water to make the system transparent. If the addition amount is increased from the permissible range as much as possible, there will be a problem that the cohesive force will be repelled by the increase in the charge in the system and the cohesive force will be greatly reduced, and the particles that have aggregated and precipitated in the system will float again. That is, when the turbidity of the aqueous solution resulting from the floating of the charged floating particles is measured as a function of the amount of the coagulating precipitant, the change in turbidity shows a V shape with respect to the amount added. On the other hand, the aggregation precipitation agent of the present invention partially neutralizes the charges of the cationic polymer and the anionic polymer due to the formation of the floc, resulting in a weakening of the charge caused by the ions, resulting in an aggregation effect. The range of the addition amount required for expression can be widened. That is, the coagulating precipitant of the present invention has a feature that the change in turbidity shows a shape close to a U shape with respect to the added amount. Even if the coagulating precipitant is added slightly less or more than the set value, the cohesive force can be maintained in the same manner for the charged floating particles contained in the waste water or waste water. For this reason, when a large amount of contaminated water or waste water is subjected to a water purification treatment over a wide range, the necessity of dealing with the amount of addition of the coagulating precipitant is reduced, and an efficient treatment can be performed. Furthermore, since the allowable range of the addition amount of the coagulating precipitant during the water purification treatment can be widened, it has a great margin for problems caused by human errors or device malfunctions. Such a problem cannot be said to have been sufficiently recognized in the art, and this effect is unique to the coagulating precipitation agent of the present invention. This feature will be described in detail in the embodiments described later.

  The aggregation precipitation agent of the present invention can be used in combination with at least one of an inorganic coagulant, a pH adjuster and a surfactant as required. The pH adjusting agent is not particularly required to be added when the wastewater or wastewater being treated satisfies a desired value, but a minimum amount of acid or alkali is added otherwise. In addition, if necessary, at least one of a cationic polymer coagulant, an anionic polymer coagulant and a nonionic polymer coagulant is added to the aqueous solution of the aggregated precipitant of the present invention or a solid or powder thereof. A trace amount may be added.

  In the water purification method, the coagulating precipitation agent of the present invention is added to various wastewaters or wastewaters containing sewage, human waste, industrial wastewater, or sludge in a state where pH is adjusted if necessary, and the wastewater or wastewater is added. This is done by agglomerating and precipitating charged suspended particles and sludge that are floating inside. Thereafter, only the precipitate is separated by a filtration operation such as filtration to purify the water. In the case of a sludge precipitate, further dehydration may be performed to reduce the volume or reduce the weight as a dehydrated cake.

  The water purification method of the present invention can not only perform efficient treatment, but also provides a good cohesive force without adjusting the pH of the charged floating particles contained in the waste water or waste water. Even if pH adjustment is necessary, the addition of a pH adjusting agent such as acid or alkali can be minimized, so that changes in the ion concentration and pH of the purified water can be suppressed as much as possible, and a safer water purification system is constructed. It becomes possible.

  The present invention will be described with reference to examples, but the scope of the present invention is not limited to these examples.

<Examples 1-8, Comparative Examples 1-2>
Sodium salt of carboxymethyl cellulose represented by the following formula (1) as an anionic polymer (Daicel Chemical Industries, Ltd., trade name CMC Daicel 1220: molecular weight 160,000 to 380,000, hereinafter abbreviated as CMC), and a cationic polymer And polydiallyldimethylammonium hydrochloride (or chloride) represented by the following formula (2) (Senka Co., Ltd., trade name: Unisense FPA1001L: molecular weight: 100,000 to 500,000, hereinafter abbreviated as PDADMAC) and a polyanion excess (CMC excess) ) Or polycation-excess (PDADMAC-excess) aqueous solutions, respectively, were prepared as polyion complex aqueous solutions.

The CMC represented by the formula (1) has a degree of etherification of 0.8 to 1.0. Here, the degree of etherification, -R parts of CMC of -O-R is the number obtained by replacing the _-CH 2 COONa, employing 0.9 average as degree of etherification in the present embodiment. When the degree of etherification is 0 and 1, the molecular weight per mol is 162 g and 242 g, respectively. When the degree of etherification of CMC is 0.9, the apparent molecular weight can be calculated as 162 (g / mol) × 0.1 + 242 (g / mol) × 0.9 = 234 (g / mol). Since 0.9 equivalent of negative charge exists per repeating structural unit represented by the above formula (1) of CMC, the ion equivalent mass (EW ₁ ) can be calculated at 234 g / 0.9 equivalent. On the other hand, PDADMAC has a molecular weight of 161.7 g per mol, high purity, and 1 equivalent of the charge per repeating structural unit represented by the above formula (2), so that the ion equivalent mass (EW ₂ ) is 161.g. It can be calculated at 7 g / 1 equivalent, which is the same as the molecular weight of the repeating structural unit.

An anionic polymer-excess polyion complex aqueous solution was added to a certain amount (10 ml) of PDADMAC having a concentration of 0.8 mol / L (liter), and CMC and PDADMAC were added little by little. Based on the respective ion equivalent masses (EW ₁ and EW ₂ ), a predetermined charge ratio was prepared. The polyion complex aqueous solution with an excess of cationic polymer was added to a certain amount (10 ml) of CMC with a concentration of 0.8 mol / L, and PDADMAC with a concentration of 0.8 mol / L was added little by little. It prepared so that it might become. The properties of each aqueous solution were examined to determine whether or not the aqueous solution was a colloidal aqueous solution in which precipitates were not dried, and the molar ratio of each ionic polymer when it was a colloidal aqueous solution or a precipitation region was measured. The result is shown in FIG.

  As shown in FIG. 4, when the anionic polymer is excessive, the charge ratio of CAD to PDADMAC is 4.1 times or more, and when the cationic polymer is adjusted excessively, the charge of PDADMAC to CMC. When the ratio was 31 times or more, it was possible to obtain an opaque or milky white colloidal solution that did not produce a precipitate. The soil fixing strength and the fixing thickness when the opaque or milky white colloid aqueous solution prepared as described above was used as a soil solidifying agent were measured.

  First, in the aqueous solution in the colloidal region where no precipitate is generated as shown in FIG. 4, the charge ratio of PDADMAC: CMC is 1: 4.1, 1: 6.8, 1:11 because the anionic polymer is excessive. And an aqueous solution having a charge ratio of PDADMAC: CMC of 31: 1, 32: 1, 35: 1, and 36: 1, respectively, with an excess of the cationic polymer. Here, the aqueous solutions in which the anionic polymer is excessive are designated as Examples 1, 2, 3 and 4 in this order, and the aqueous solutions in which the cationic polymer is excessive are designated in Examples 5, 6, 7 and 8 in this order.

  For comparison, the soil fixing strength was measured when sprayed only with water that did not contain a polyion complex. Furthermore, a cationic polymer and an anionic polymer are mixed at an equal charge ratio (1: 1), and after adding 4% by mass of NaCl as a salt, the mixture is stirred until no precipitate is formed. Adjusted. Here, the above-mentioned PDADMAC is used for the cationic polymer, and sodium polyacrylate (PAANA) (Nippon Shokubai Co., Ltd. trade name Aqualic DL522: molecular weight 170,000) represented by the following formula (3) is used for the anionic polymer. It was. This aqueous solution is a simulation of the aqueous solution used as a soil decontamination agent for decontamination at the Chernobyl nuclear power plant explosion accident.

Incidentally, since PDADMAC, CMC, and PAANA, as shown in the above formulas (1) to (3), have a counter ion of Na ⁺ or Cl ⁻ , an aqueous solution containing these ionic polymers eventually becomes a cation. And anions. For example, a colloidal aqueous solution having a charge ratio of PDADMAC: CMC = 1: 4.1 includes a total mass of these ionic polymers in a range of 0.5 g to 1.7 g with respect to 100 ml of the colloidal aqueous solution. As a result of measuring the contents of Na ⁺ and Cl ⁻ , it was found to be 0.028 to 0.094 mass% and 0.014 to 0.048 mass%, respectively. Moreover, the colloid aqueous solution whose charge ratio is PDADMAC: CMC = 31: 1 is 0.002-0.006 mass% and 0.104-0.354 mass% in the same concentration range, respectively. Even if the total mass of the cationic polymer and the anionic polymer is 10% (w / v) with respect to 100 ml of the colloidal aqueous solution, Na is used when used as the soil fixing agent of the present invention. ^It can be inferred that the total ion content of ⁺ and Cl ⁻ is less than 2.2% by mass (corresponding counterion concentration when the total mass of the cationic polymer and the anionic polymer is 10%). . On the other hand, in Comparative Example 2, since 4% by mass of NaCl salt was added in addition to the counter ion, the ion concentration in the aqueous solution was very high compared to the Example.

FIG. 5 shows an experimental method for measuring the soil fixation strength of the present invention. As shown in FIG. 5, 300 g of commercially available black soil dried for 1 day was put in a 12 × 12 cm container, and a load of about 5 kg from above was used as a soil model. The colloidal aqueous solution of Examples 1 to 8, which is a dispersion type polymer flocculant of the present invention, was sprayed at 5 L / m ² from above and dried in a drier at 60 ° C. For samples that can be measured for soil fixation strength, determine the weight of the container and confirm that the water in the application amount (the weight of water is calculated as 1 g per cm ³ ) has almost completely evaporated. The soil fixation strength was measured. The soil fixation strength by solidification was measured at 5 points per sample using a Yamanaka type soil hardness meter. Moreover, the thickness of soil fixation measured the thickness of the part formed as a continuous layer of soil with a scale (mm).

  6 and 7 show the ionic properties of the dispersion polymer flocculant in which the anionic polymer is excessively adjusted by the charge ratio and the dispersion polymer flocculant in which the cationic polymer is excessively adjusted by the charge ratio. The measurement result of soil fixed strength when the total content of the polymer is 1% (w / v) is shown. In the figure, the case of only water (Comparative Example 1) and the aqueous solution (Comparative Example 2) in which the cationic polymer and the anionic polymer are mixed at an equal charge ratio (1: 1) are also shown. As can be seen from FIG. 6 and FIG. 7, in each of the anionic polymer (CMC) excess or the cationic polymer (PDADMAC) excess in the charge ratio, the soil fixation strength increases as the charge ratio becomes closer to the precipitate generation region. (Example 1 and Example 5). As shown in FIG. 6, when the CMC was excessive, a higher soil fixation strength was obtained compared to Comparative Examples 1 and 2, and in particular, Example 1 was about 4 times as high as Comparative Example 2. On the other hand, as shown in FIG. 7, when PDADMAC is excessive, the soil fixing strength is higher than that of Comparative Example 1 in which water is used alone, but is lower than that of Comparative Example 2 in which the molar ratio is 1: 1.

  The reason why only a low soil fixing strength was obtained in the dispersive polymer flocculant prepared by the excess of PDADMAC is that the colloidal properties in which PDADMAC is uniformly dispersed unless the charge ratio is 31 times or more with respect to CMC in this colloidal aqueous solution. This indicates that the flocs formed by the polyion complex cannot be sufficiently formed. Therefore, with respect to Example 1 having the highest soil fixing strength, the soil fixing strength, the thickness of the soil fixing, and the polymer concentration, which means the total content of ionic polymers contained in the colloidal aqueous solution of the dispersed polymer flocculant, I investigated the relationship.

  8 (a) and 8 (b), the soil fixation strength and the soil fixation thickness when the dispersion type polymer flocculant (Example 1) having a charge ratio of PDADMAC: CMC = 1: 4.1 is used. Each measurement result is shown. As shown in FIG. 8, it can be seen that when the content of the dispersed polymer flocculant is 0.5 g or less [0.5% (w / v)] by mass with respect to 100 ml of the colloidal aqueous solution, the soil cannot be solidified. Further, although not shown in FIG. 8, when the content exceeds 10 g [10% (w / v)] by mass with respect to 100 ml of the colloidal aqueous solution, the soil fixing strength tends to be saturated, It has been found that the colloidal solution has a very fixed thickness of 3 mm or less and has a large problem when used as a soil solidifying agent. Therefore, the colloidal aqueous solution of this example has a polymer that is a combination of the cationic polymer and the anionic polymer in a mass exceeding 0.5% (w / v) to 10% with respect to 100 ml of the colloidal aqueous solution. (W / v) It is necessary to contain below.

  Subsequently, in order to verify the effect of soil solidification by the dispersed polymer flocculant of this example, the amount of dust in the soil after solidification was measured. A method for measuring the amount of dust is schematically shown in FIG. As shown in FIG. 9, 400 g of dried black clay in a 12 × 17 cm container was put, and the load was applied to the soil in the same manner as in the case of soil fixing strength. After that, the one that was sprayed and dried with the colloidal aqueous solution of Examples 1 and 5 was measured, and the soaring soil in the flow of wind with a wind speed of 15 m / s was sucked with a vacuum cleaner, and the sucked amount was measured as the amount of dust. . The wind speed of 15 m / s is defined as “strong wind” by the Japan Meteorological Agency, and is a wind speed that makes it difficult to walk toward the wind because the whole large tree shakes. Further, the amount of dust was measured in the same manner for the water of Comparative Example 1 and the aqueous Polyon Complex solution of Comparative Example 2. The measurement time was 20 minutes in total, and the first 5 minutes were measured every 1 minute and thereafter every 5 minutes.

  FIG. 10 shows the change in the amount of dust with the elapsed time of the soil solidified using Examples 1 and 5. Here, the sample used as Examples 1 and 5 has an ionic polymer content of 1 mg [1% (w / v)] by mass with respect to 100 ml of the colloidal aqueous solution. FIG. 10 also shows the results of changes in the amount of dust in Comparative Examples 1 and 2. 11 and 12 show 20 minutes of soil solidified using Example 5 (aqueous solution with excess cationic polymer in charge ratio) and Example 1 (aqueous solution with excess anionic polymer in charge ratio), respectively. The relationship between the amount of dust after progress and the polymer concentration, which means the total content of ionic polymers contained in the aqueous colloidal solution, is shown.

  As shown in FIG. 10, since the comparative example 1 only with water cannot obtain the effect of soil solidification, the amount of dust is the highest value. In addition, an aqueous solution (Example 1) in which the anionic polymer (CMC) is excessive in the charge ratio under the condition that the total content of the ionic polymer is 1% (w / v) has a larger amount of dust than Comparative Example 2. It can be seen that it can be suppressed. On the other hand, an aqueous solution (Example 5) in which the cationic polymer (PDADMAC) is excessive in charge ratio has a dust amount close to that when only water is sprayed. However, as shown in FIG. 11, even in an aqueous solution with a PDADMAC excess in charge ratio (Example 5), if the total content of the ionic polymer is 1.2% (w / v) or more, the amount of dust is suppressed. Compared with Comparative Example 2, the amount of dust is small and it can be sufficiently used as a soil solidifying agent. As shown in FIG. 12, the CMC-excess aqueous solution (Example 1) can obtain a great effect on reducing the amount of dust with a content exceeding 0.50% (w / v). It can be easily understood that the measurement results of FIGS. 11 and 12 have a strong correlation with the results of the soil fixing strength and the soil fixing thickness.

  Next, in order to investigate the degree of environmental load on the soil of the dispersed polymer flocculant of the present example, the germination rate of seeds from the soil after solidification was measured.

FIG. 13 shows a germination rate measuring method. 50 seeds of turf (product name: creeping red fescue) are placed in the aqueous dispersion polymer colloid used and stirred, and then stored in a container (12 × 12 cm) in an amount of 5 L / m ² . It was sprayed on soil (black soil). Two weeks later, the soil was observed, and the germination rate was measured as (number of germination / 50) × 100 (%). In the middle, 5 L / m ² of water was sprayed once a week to promote germination.

  Table 1 shows the germination rate after 2 weeks for the soil after spraying using the above-described Examples 1 and 5 as a colloidal aqueous solution of a dispersive polymer flocculant. In Table 1, for comparison, soil when sprayed only with water not containing a polyion complex, and PDADMAC and PAANA are mixed at an equal charge ratio (1: 1), and further 4% by mass of NaCl as a salt. About the soil when the added aqueous solution is sprayed, the results of germination rate are also shown as Comparative Examples 1 and 2, respectively. The mass ratio and the molar ratio in the table indicate the mass and the number of moles of the cationic polymer and the anionic polymer that were actually blended as the blending ratio of both polymers, respectively. Moreover, the density | concentration of an ionic polymer means the ratio when the total mass of the cationic polymer and anionic polymer contained in 100 ml of aqueous solution is represented by mg unit, and represents it with% (w / v).

  As shown in Table 1, the germination rate of Examples 1 and 5 exceeds 80%, and it can be seen that there is almost no adverse effect on turf germination even when compared with Comparative Example 1 in which only water was sprayed. Table 1 shows the result of 1% (w / v) as the concentration of the ionic polymer, but it has been confirmed that the germination rate is 60% or more up to 2% (w / v). On the other hand, since Comparative Example 2 contains a large amount of salt in addition to the counter ion, the germination rate is significantly reduced, and there is a concern about an adverse effect on the environment. As described above, this example has a relatively high soil fixing strength and has excellent characteristics not found in conventional polyion complex aqueous solutions in that it does not inhibit plant growth, and is an environmentally friendly soil solidifying agent. It is a suitable dispersion type polymer flocculant for application.

<Examples 9 to 16>
Using PAANAa represented by the above formula (3) as the anionic polymer and PDADMAC represented by the above formula (2) as the cationic polymer, an aqueous solution containing polyanion (PAANA) excess or polycation (PDADMAC) excess was obtained. Each was prepared and used as a polyion complex aqueous solution. Since PAANA has a high purity and the charge per repeating structural unit represented by the above formula (3) is present at 1 equivalent, the ion equivalent mass (EW ₂ ) can be calculated at 94 g / 1 equivalent, which is the molecular weight of the repeating structural unit. And 94 (g / mol).

An anionic polymer-excess polyion complex aqueous solution was added to a certain amount (10 ml) of PDADMAC having a concentration of 0.0378 mol / L (liter), and PAANA Na having a concentration of 0.0378 mol / L was added little by little. Were prepared so as to have a predetermined charge ratio based on the respective ion equivalent masses (EW ₁ and EW ₂ ). The cationic polymer-excess polyion complex aqueous solution was prepared by adding DADMAC with a concentration of 0.0378 mol / L little by little to a fixed amount (10 ml) of PAANA at a concentration of 0.0378 mol / L. It prepared so that it might become. Investigate the properties of each aqueous solution to determine whether it is a colloidal aqueous solution that does not produce precipitates in the system, and measure the charge ratio of each ionic polymer when it becomes a colloid region or a precipitate formation region did. The result is shown in FIG.

  In FIG. 14, the polyion complex aqueous solution of PAANA and PDADMAC produced a precipitate on the glue in the precipitation generation region. Further, this polyion complex aqueous solution has a charge ratio indicating a colloidal region different from that of the polyion complex aqueous solution composed of a combination of CMC and PDADMAC shown in FIG. As shown in FIG. 14, when the amount of the anionic polymer is excessive, the charge ratio of PAADa to PDADMAC is 10 times or more, and when the amount of the cationic polymer is adjusted excessively, the charge ratio of PDADMAC to PAANA is When the ratio was 4 times or more, an opaque or milky white colloidal solution that did not produce a precipitate could be obtained. Experiments were conducted on soil fixation strength and thickness when the thus prepared opaque or milky white colloidal aqueous solution was used as a soil solidifying agent.

  First, in the aqueous solution in the colloidal region where no precipitate is formed as shown in FIG. 14, the charge ratio of PDADMAC: PAANAe is 1:10, 1:12, 1:14 and 1:15 assuming that the anionic polymer is excessive. The aqueous solution of PDADMAC: PAANa having a charge ratio of 4: 1, 6: 1, 8: 1, and 10: 1 was prepared using a cationic polymer in excess as a sample. Here, the aqueous solutions in which the anionic polymer is excessive are referred to as Examples 9, 10, 11 and 12 in this order, and the aqueous solutions in which the cationic polymer is excessive are referred to as Examples 13, 14, 15 and 16 in this order. The soil fixing strength and the fixing thickness were measured according to the method shown in FIG. 5 in the same manner as in Examples 1-8.

Incidentally, the aqueous solution containing these ionic polymers contains cations and anions as a result of the presence of counterions. For example, a colloidal aqueous solution having a charge ratio of PDADMAC: PAANAa = 1: 10 has a total mass of these ionic polymers of 1 g [1% (w / v)] to 5 g [5% (100%) with respect to 100 ml of the colloidal aqueous solution. w / v)], the contents of Na ⁺ and Cl ⁻ were measured, and as a result, they were 0.206 to 1.021% by mass and 0.032 to 0.158% by mass, respectively. I understood. Moreover, the colloid aqueous solution whose charge ratio is PDADMAC: PAANAa = 4: 1 is 0.048-0.237 mass% and 0.124-0.615 mass%, respectively in the same concentration range. Even if the cationic polymer and the anionic polymer are contained in a total amount close to 10% (w / v) with respect to 100 ml of the colloidal aqueous solution, Na is used when used as the soil fixing agent of the present invention. ^It can be inferred that the total ion content of ⁺ and Cl ⁻ is less than 2.4% by mass.

  FIGS. 15 and 16 respectively show a dispersive polymer flocculant in which an anionic polymer (PAANA) is excessively adjusted by a charge ratio and a dispersive polymer aggregate in which a cationic polymer (PDADMAC) is excessively adjusted by a charge ratio. About each of the agent, the measurement result of soil fixed strength when changing the charge ratio of both ionic polymers is shown. Here, FIG. 15 shows that the concentration of PDADMAC is fixed at 0.5% (w / v), and a colloidal solution formed by adding PAANANa in a charge ratio of 10 to 15 times is sprayed on this to fix the soil fixation strength. Was investigated. FIG. 16 shows that the concentration of PAANA is fixed at 0.5% (w / v), and colloidal solution formed by adding PDADMAC in a charge ratio of 4 to 10 times is sprayed on this to fix the soil fixation strength. It has been investigated. As can be seen from FIG. 15 and FIG. 16, in each of the dispersed polymer flocculants with an excess of PAANA Na or PDADMAC in terms of charge ratio, the soil fixation strength becomes higher as the charge ratio becomes closer to the precipitate generation region (Example 9 and Example 13). Further, as shown in FIG. 15, when the charge ratio is excessive PAANA, a higher soil fixation strength is obtained compared to Comparative Example 2 shown in FIG. 6, and in particular, Examples 9 and 10 are about 4 compared to Comparative Example 2. A value as high as twice or more is shown. Furthermore, as shown in FIG. 16, even when PDADMAC is excessive in terms of charge ratio, the soil fixation strength has a value equal to or higher than that of Comparative Example 2.

  The difference in soil fixation strength observed between the dispersion polymer flocculant with excess anionic polymer and the cationic polymer excess in charge ratio is the black soil used as the soil sample. It can be inferred that this is related to the difference in ionicity and pH. Moreover, Examples 13-16 differed from Examples 5-8, and were able to obtain comparatively high soil fixation strength, the charge ratio with respect to anionic polymer of a cationic polymer was 4 or more, and smaller This is considered to be because a colloidal aqueous solution uniformly dispersed with a charge ratio could be produced.

  Subsequently, for Example 9 and Example 13, the relationship between the soil fixation strength and the soil fixation thickness and the total polymer content contained in the dispersed polymer flocculant was examined. Although the measurement result of the soil fixation strength is omitted, the soil fixation strength is similar to the combination of PDADMAC and CMC shown in FIG. It tends to be higher. Further, when comparing an aqueous solution containing excess anionic polymer and an aqueous solution containing excess cationic polymer, the former tends to increase the soil fixing strength.

  Soil fixed thickness and ionic polymer measured for dispersion polymer flocculant with excess anionic polymer in charge ratio (Example 9) and dispersion polymer flocculant with excess cationic polymer (Example 13) FIG. 17 (a) and FIG. 17 (b) show the relationship with the polymer concentration meaning the total content of. As shown in FIG. 17, in both Example 9 and Example 13, the fixed thickness of the soil tends to increase as the polymer concentration increases. In Example 9, the polymer concentration is less than 2.0% (w / v), and in Example 13, the polymer concentration is less than 1.0% (w / v), and the soil is sufficiently fixed. I could not. Therefore, when this example is used as a soil solidifying agent, it is necessary to set the lower limit of the concentration of the polymer contained in the aqueous solution in accordance with the charge ratio between the cationic polymer and the anionic polymer. Further, if the upper limit of the polymer concentration is up to 10% (w / v), a significant increase in viscosity of the colloidal aqueous solution can be suppressed, and the fixed thickness of the soil does not show a large change as shown in FIG. . Therefore, in the dispersion type polymer flocculant of the present example, the content of the polymer, which is the combination of the cationic polymer and the anionic polymer, exceeds 10 g in mass with respect to 100 ml of the colloidal aqueous solution and exceeds 10 g. It is necessary to stipulate below, that is, more than 1% (w / v) and 10% (w / v) or less.

  In addition, the measurement result shown to (a) of FIG. 17 differs from the aqueous solution containing PDADMAC and CMC shown to (b) of FIG. 8, and soil fixed thickness will become thick when the polymer concentration in aqueous solution increases. There is a tendency. This tendency is observed in the same way whether PDADMAC is excessive or PAANA is excessive. As the polymer concentration in the aqueous solution increases and the viscosity increases, the soil fixed thickness generally decreases, but the combination of PDADMAC and PAANA was found to behave in a specific manner. This is because the behavior of the combination of PDADMAC and PAANA is observed because the colloidal particles contained in the aqueous solution are smaller than the combination of PDADMAC and CMC, and the movement or migration of the colloidal particles into the interparticle gaps in the soil is fast. However, details are unknown.

  Subsequently, in order to verify the effect of soil solidification by the dispersive polymer flocculant of this example, the amount of dust in the soil after solidification was measured for Example 9 and Example 13. The amount of dust was measured according to the method shown in FIG.

  FIG. 18 shows the progress of the polymer flocculant having a polymer concentration of 2% (w / v) in Example 9 and the polymer flocculant having a polymer concentration of 3% (w / v) in Example 13. The change in the amount of soil dust with time is shown. FIG. 18 also shows the results of changes in the amount of dust in Comparative Examples 1 and 2. Moreover, in FIG.19 and FIG.20, the polymer concentration (w / v) which means the total content of ionic polymer about the aqueous solution of Example 9 and Example 13, and the amount of dust after progress for 20 minutes, respectively. Indicates.

  As shown in FIG. 18, both Example 9 and Example 13 can significantly reduce the amount of dust compared to Comparative Example 2. In addition, Example 9 shown in FIG. 19 has an effect of reducing the amount of dust when the polymer concentration is 1% (w / v) or more, and greatly suppresses the generation of dust when it is 2% (w / v) or more. Can do. On the other hand, in Example 13 shown in FIG. 20, the polymer concentration capable of greatly reducing the amount of dust is 2% (w / v) or more. It can be easily understood that the measurement results of FIGS. 19 and 20 have a strong correlation with the measurement results of the fixed thickness of the soil shown in FIGS.

  Next, in order to investigate the degree of environmental load on the soil of the dispersed polymer flocculant of the present example, the germination rate of seeds from the soil after solidification was measured. The germination rate was measured according to the method shown in FIG.

  Table 2 shows the germination rate after 2 weeks for the soil after being sprayed using Examples 9 and 13 as a colloidal aqueous solution of a dispersion type polymer flocculant. Table 2 also shows the results of measuring germination rates in Comparative Examples 1 and 2. The mass ratio and the molar ratio in the table indicate the mass and the number of moles of the cationic polymer and the anionic polymer that were actually blended as the blending ratio of both polymers, respectively. Moreover, the density | concentration of an ionic polymer means the ratio when the total mass of the cationic polymer and anionic polymer contained in 100 ml of aqueous solution is represented by g unit, and is represented by% (w / v).

  As shown in Table 2, the germination rate of Examples 9 and 13 exceeds 80%, and it can be seen that there is almost no adverse effect on the germination of turf even when compared with Comparative Example 1 in which only water was sprayed. Table 2 shows the results of 2% (w / v) and 3% (w / v) as the polymer concentration of the ionic polymer, but the germination rate is 70% up to 5% (w / v). This is confirmed. Thus, this example has a relatively high soil fixing strength and does not inhibit the growth of plants, and thus has an excellent feature not found in conventional polyion complex aqueous solutions. The combination of the above DADMAC and CMC Similarly, it is a suitable dispersion type polymer flocculant for application as an environmentally friendly soil solidifying agent.

  As described above, the dispersion type polymer flocculants according to the above Examples 1 to 16 not only have a good cohesive force as compared with the conventional polymer flocculants but also can greatly reduce the burden on the environment. By applying it as a soil solidifying agent for any one of the methods for expanding the contamination of substances, the decontamination method for contaminated soil, and the vegetation base construction method, the characteristics can be fully utilized. Among them, with regard to the method for expanding the contamination of radioactive substances and the method for decontamination of contaminated soil, the dispersion type polymer flocculant of the present invention is used together with a suspension having clay fine particles such as zeolite and bentonite, so that cesium, etc. The effectiveness as a decontamination method for radioactive materials can be greatly increased. Therefore, a decontamination method for contaminated soil will be described using an example as an example of application.

<Example 17>
In the dispersed polymer flocculant of Example 1, using a colloidal aqueous solution with the polymer concentration adjusted to 1% (w / v), the soil was contaminated with radioactive material such as cesium at room temperature (about 20 ° C. ) In 5 L / m ² , uniformly applied by a spray device and left at room temperature for 3 days to form a continuous layer composed of contaminated soil fixed with an ionic polymer in a dispersive polymer flocculant The continuous layer was peeled off. As a result of measuring the respective radiation doses for the soil surface after peeling off the initial contaminated soil surface and the continuous layer, the ratio of the radiation dose after peeling to the initial stage is 20%, and the decontamination rate is 80%. there were.

<Example 18>
After spraying a suspension aqueous solution containing 0.5% by mass of bentonite donmine, which is a kind of bentonite (made by Volclay Japan Co., Ltd.) as clay particles, uniformly over the soil with a spray device under the condition of 5 L / m ² , In the same manner as in Example 17, the colloidal aqueous solution of the dispersion type polymer flocculant of Example 1 was uniformly sprayed from the soil. After standing at room temperature for 3 days, a continuous layer composed of contaminated soil containing bentonite particles and fixed by an ionic polymer in a dispersed polymer flocculant was formed, and then the continuous layer was peeled off. About the soil surface after exfoliating the initial contaminated soil surface and the continuous layer, the radiation dose was measured by the same method as in Example 17. As a result, the ratio of the radiation dose after exfoliation to the initial stage was 10%, and decontamination The rate was 90%. In this way, it is confirmed that the dispersion type polymer flocculant of the present invention is sprayed, and then a suspension containing clay particles such as bentonite is sprayed to increase the decontamination rate of the contaminated soil. It was done. In the present invention, it has been confirmed that the radiation dose can be reduced even if zeolite is used instead of bentonite as clay particles.

  The dispersion type polymer agent of the present invention can increase the particle size of the aggregated precipitate of the floating charged particles by improving the cohesive force when applied as a coagulant precipitation agent applied to the water purification method for domestic wastewater and industrial wastewater. In addition to the effect, as described above, there is an unprecedented effect that the allowable range for the addition amount fluctuation of the coagulating precipitation agent can be widened. Then, the coagulating precipitation agent to which the dispersion type polymer agent of the present invention is applied will be described with reference to examples.

<Examples 19 to 20, Comparative Examples 3 to 4>
CMC (molecular weight: about 1.11 million) represented by the above formula (1) was used as the anionic polymer, and PDADMAC represented by the above formula (2) was used as the cationic polymer. For PDADAMAC, 1001L (molecular weight: 100,000 to 500,000) and 1002L (molecular weight: 500,000 to 1,000,000) having different molecular weights were used for the experiment. Adjust the PDADMAC to 0.06 mol / L and CMC to 0.0035 mol / L, and stir the PDADMAC aqueous solution while stirring the PDADMAC aqueous solution so that the charge ratio of both is PDADMAC: CMC = 1: 5. added. Water was added to this aqueous solution to prepare an anion-excess colloidal aqueous solution so that the polymer concentration of PDADMAC and CMC was 0.2% (w / v). As comparative examples, aqueous solutions containing 0.2% (w / v) of PDADMAC1001L and PDADMAC1002 alone were used as Comparative Example 3 and Comparative Example 4, respectively. A colloidal aqueous solution prepared by adding CMC to each of PDADMAC1001L and PDADMAC1002 according to the above-described method so that the charge ratio is PDADMAC: CMC = 1: 5 is referred to as Example 19 and Example 20, respectively.

  In this example, domestic wastewater and industrial wastewater were simulated and distilled using bentonite (bentonite donmin: Volcure Japan Co., Ltd.), which is clay particles, so that the content of bentonite is 0.1% by mass. A dispersion in which water was added and uniformly dispersed was used. Here, bentonite fine particles can be considered as floating charged particles contained in domestic wastewater and industrial wastewater.

  Next, 100 mL of a dispersion having a bentonite content of 0.1% by mass was placed in a beaker, and while stirring, the previously prepared colloidal aqueous solution was added dropwise and stirred for 1 minute, then the stirring was stopped and the mixture was allowed to stand for 5 minutes. . Using the supernatant of the aqueous solution after standing for 5 minutes, turbidity (mg / L) is measured at a wavelength of 660 nm using a UV-1200 UV-visible spectrophotometer manufactured by Shimadzu Corporation. Here, the smaller the value of the turbidity, the more the agglomeration of bentonite proceeds, and the aqueous solution becomes transparent. Therefore, in this example, the dropping amount of the aqueous colloidal solution was measured in a range where the turbidity was 50 or less. Here, as the dripping amount, a value converted into the total amount of the anionic polymer and the cationic polymer contained in the bentonite dispersion was used.

  In each of the supernatants of bentonite suspensions to which the aqueous solutions of Comparative Examples 3 and 4 and Examples 19 and 20 were added to (a) and (b) of FIG. The result of having measured turbidity with respect to the total amount (mg) is shown. As shown in FIG. 21, the turbidity of the supernatant liquid decreases rapidly and precipitates are generated as the amount of the coagulating precipitant made of ionic polymer increases. Thereafter, the turbidity increases, and the dispersion of bentonite particles or aggregates thereof is observed again in the supernatant. In Comparative Examples 3 and 4 shown in FIG. 21 (a), it can be seen that the change of the turbidity with respect to the total amount of the polymer is abrupt and shows a V-shaped turbidity change. In Comparative Examples 3 and 4, the increase in turbidity observed when an excessive amount of the coagulating precipitant is added causes the particles aggregated by the excessive coagulating precipitant to become positively charged again, It is thought that it was difficult to settle due to repulsion.

  On the other hand, as shown in FIG. 21B, the coagulating sedimentation agent of this example shows that the change in turbidity is relatively slow and shows a U-shaped turbidity change. As shown in FIG. 1, the coagulating precipitants of Examples 19 and 20 were partially neutralized with the charges of the cationic polymer and the anionic polymer due to the formation of flocs. In comparison, the positive charge was weakened, and it was found that the curve showing the change in turbidity showed a large spread sideways. Further, the U-shaped turbidity change shown in (b) of FIG. 21 can move to the left and right with respect to the total amount of the polymer, although it is slight, depending on the molecular weight of each ionic polymer. Furthermore, the shape itself can be changed in a wider form. Such behavior has hardly been clarified so far, and is considered to be unique to the coagulating precipitation agent of the present invention.

  As described above, the coagulation precipitation agent of this example shows a shape in which the change in turbidity is close to a U shape with respect to the total amount of the polymer. The range of quantity can be widened. Even if the aggregation precipitant is added slightly less or more than the set value due to a human error or a malfunction of the apparatus, the cohesion force can be maintained in the same manner for the charged floating particles contained in the waste water or waste water. For this reason, when a large amount of contaminated water or waste water is subjected to a water purification process over a wide range, the necessity of dealing with the amount of addition of the coagulating precipitant is reduced, and an efficient treatment can be performed. Furthermore, it was confirmed that the aggregated precipitant of this example had a slightly larger particle size than the aggregated precipitants of Comparative Examples 3 and 4, so that the aggregated precipitate was separated and trapped. Easy to collect. In addition, since the aggregated precipitate having a relatively large diameter contains a large number of pores inside, there is also an effect that the water contained in the aggregated precipitate can be easily separated.

  As described above, the dispersion type polymer flocculant in an aqueous solution containing an excess of either the cationic polymer or the anionic polymer of the present invention does not generate a precipitate even in a state where no excess salt is contained. In order to form a uniform colloidal aqueous solution that is stable for a long period of time, it can be used as a one-part polymer flocculant aqueous solution. In addition, a large cohesive force can be obtained when added to domestic wastewater, industrial wastewater or soil, etc., so that a soil solidifying agent capable of effective soil solidification and a coagulating precipitant that can also be applied to efficient water purification Can be used respectively. Furthermore, since the dispersive polymer flocculant of the present invention can be used in a state in which the content of a salt that may inhibit plant growth is reduced, it can be used when applied as a soil solidifying agent and an aggregating precipitant. The load on the environment can be reduced and its usefulness is extremely wide.

Claims (18)

A dispersion type polymer flocculant in an aqueous solution containing a cationic polymer and an anionic polymer, wherein the cationic polymer and the anionic polymer have either polymer as a first polymer, The other polymer is the second polymer, and the value obtained by dividing the blending amount (C ₁ ) of the first polymer by the ion equivalent mass (EW ₁ ) of the first polymer (C ₁ / EW ₁ ) and a value (C ₂ / EW ₂ ) obtained by dividing the blend amount (C ₂ ) of the second polymer by the ion equivalent mass (EW ₂ ) of the second polymer (C ₁ / EW ₁ ) :( C ₂ / EW ₂ ) = 1: 1, and assuming that the charge ratio is 1, the relationship of (C ₁ / EW ₁ ) / (C ₂ / EW ₂ )> 1 is established. The first polymer is blended in excess of the second polymer so as to satisfy, and the aqueous solution Distributed polymer coagulant characterized in that not produce a precipitate, opaque or milky colloid solution.   The aqueous colloidal solution is sodium chloride, potassium chloride, ammonium chloride, magnesium chloride, sodium sulfate, potassium sulfate, ammonium sulfate, magnesium sulfate, sodium nitrate as a salt other than the counter ion contained in the cationic polymer or the anionic polymer. And at least one salt selected from potassium nitrate and ammonium nitrate, and when the total amount of the aqueous colloidal solution is 100 parts by mass, the total concentration of ions combining the cations and anions constituting the salt is 1.5 masses. The dispersive polymer flocculant according to claim 1, wherein the dispersive polymer flocculant is less than%. The first polymer has a compounding amount with which the charge ratio, which is a value obtained by dividing the (C ₁ / EW ₁ ) by the (C ₂ / EW ₂ ) with respect to the second polymer, is twice or more. And the colloid aqueous solution does not contain a salt other than the counter ion contained in the cationic polymer or the anionic polymer. .   The upper limit value of the blending amount when the first polymer is excessively blended with the second polymer is to maintain a translucent or milky white uniform state in which the colloidal aqueous solution does not form a precipitate. The dispersion type polymer flocculant according to any one of claims 1 to 3, wherein the amount is a blending amount until it can be formed. The cationic polymer is at least one selected from cationized cellulose, cationized starch, a polymer having an amino group, or a polymer of a quaternary ammonium salt;
The anionic polymer is at least one selected from carboxymethyl cellulose, carboxymethyl amylose, lignin sulfonic acid and its salt, polyacrylic acid and its salt, polysulfonic acid and its salt. 5. The dispersion type polymer flocculant according to any one of 4 above.   The dispersion type polymer flocculant according to any one of claims 1 to 5, wherein the colloid aqueous solution has a mass of a polymer obtained by combining the cationic polymer and the anionic polymer with respect to 100 ml of the colloid aqueous solution. A soil solidifying agent characterized by containing in a range of more than 0.5 g and 10 g or less.   The dispersion type polymer flocculant according to any one of claims 1 to 5, wherein the colloid aqueous solution has a mass of a polymer obtained by combining the cationic polymer and the anionic polymer with respect to 100 ml of the colloid aqueous solution. In a range of more than 0.1 g and 10 g or less.   It is a solid obtained as a residue after removing water from the dispersed polymer flocculant according to any one of claims 1 to 5, or a powder obtained by pulverizing the solid. Coagulating precipitating agent.   A method for preventing the spread of radioactive material contamination, wherein the soil solidifying agent according to claim 6 is sprayed on soil contaminated with radioactive cesium, and then the soil is fixed to prevent migration and diffusion of the radioactive material.   A soil-contaminated soil according to claim 6 is applied to soil contaminated with radioactive cesium to fix at least a part of the soil, and then the surface layer of the soil is peeled and removed. Decontamination method.   By dispersing the suspension having clay fine particles and the soil solidifying agent according to claim 6 in this order to the soil contaminated with radioactive cesium, the radioactive cesium is taken into the clay fine particles, and the radioactive cesium is taken in. A method for preventing the spread of radioactive substances by preventing the movement and diffusion of radioactive substances by solidifying soil containing fine clay particles.   The method according to claim 11, wherein the clay fine particles are at least one of bentonite and zeolite.   The radioactive substance contamination expansion preventing method according to claim 11 or 12, wherein the suspension containing the clay fine particles is an aqueous solution containing 0.05 to 5% by mass of the clay fine particles.   By dispersing the suspension having clay fine particles and the soil solidifying agent according to claim 6 in this order to the soil contaminated with radioactive cesium, the radioactive cesium is taken into the clay fine particles, and the radioactive cesium is taken in. A method for decontaminating contaminated soil, comprising: solidifying at least a part of the soil with the soil solidifying agent after removing soil containing clay fine particles from the soil;   The method for decontamination of contaminated soil according to claim 14, wherein the clay fine particles are at least one of bentonite and zeolite.   The decontamination method for contaminated soil according to claim 14 or 15, wherein the suspension containing the clay fine particles is an aqueous solution containing 0.05 to 5% by mass of the clay fine particles.   A vegetation foundation creation method, wherein the soil solidifying agent according to claim 6 is sprayed onto the soil on the construction surface to solidify the surface layer of the soil, thereby creating the soil on the construction surface and greening.   9. A water purification method, wherein water purification is performed by mixing the coagulating precipitant according to claim 7 or 8 in contaminated water or waste water, and precipitating charged floating particles contained in the contaminated water or waste water.

Images