JPH09227117A - Hydrogen ion type modified smectite, water purifying agent and method for producing hydrogen ion type modified smectite - Google Patents

Abstract

(57) [Summary] A pH of a 1% by weight pure water slurry is 2.5-.
The hydrogen-ion-type modified smectite having a conductivity of 4.5 and an electric conductivity of 120 to 950 μS. [Effect] The hydrogen ion-type modified smectite of the present invention has an excellent effect of removing impurities in water and is suitable as a water purifying agent. Further, according to the production method of the present invention, the smectite slurry can be efficiently concentrated. The hydrogen ion type modified smectite can be manufactured reliably and easily.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel hydrogen ion type modified smectite useful for purifying water by adsorbing and removing impurities in water and a water purifying agent comprising the hydrogen ion type modified smectite. Further, the present invention relates to a method for producing a hydrogen ion type modified smectite capable of efficiently concentrating an aqueous slurry of smectite and obtaining a hydrogen ion type modified smectite which can be used as a water purifying agent as described above. .

[0002]

2. Description of the Related Art Smectite has been used in various industrial fields from the past, but bentonite raw ore is crushed, and dried granules are dispersed and suspended in water. As a method of concentrating the smectite slurry of the upper layer obtained by standing, there is a concentration method by centrifugation. However, since smectite slurries are generally highly viscous, the practical concentration limit of smectite slurries by centrifugation is only about 3%. Further, in the concentration of the smectite slurry by filtration, the smectite particles are so small that they pass through the furnace material, and practical concentration is difficult to perform.

As described above, since the smectite slurry has a high viscosity and the smectite particles are very small, the evaporation concentration method by heating is effective as the concentration method.
With this method, the evaporation efficiency is small and the cost is high.
It has not been implemented as a practical method. Further, according to this method, since all the substances existing in the slurry are concentrated, highly pure water is required for preparing the slurry.

On the other hand, there is also a method in which powdered smectite is added to water to form a slurry, but in this method, the viscosity of the smectite slurry to be obtained rapidly increases with the concentration, so about 6% is the upper limit concentration obtained by this method. Is.

From these points, a method for more efficiently concentrating the smectite slurry to a high concentration is desired.

[0006] Further, in various industrial water, tap water, etc., F
e, Al, hydroxides such as Si, other colloidal ^{materials, Ca ++, Na +, Mg} ++, Fe ++, Cl -, Si
Hardness components such as O ₄ and N ₂ O _x, and impurities such as a wide variety of organic substances are contained. These impurities have hitherto been used for colloidal substances such as activated carbon, activated clay, inorganic or organic coagulation, and filters. Ion exchange resin is used for ionic substances, and activated carbon and activated clay are used for neutral organic substances.

However, although each of these means alone is effective for removing the above-mentioned specific type of impurities, it cannot remove all of the above-mentioned impurities at the same time. There was a limit to the removal. Therefore, in general, the above-mentioned means are used in combination, which is complicated in operation and may not always have a sufficient effect of removing impurities.

Therefore, it is an object of the present invention to provide a hydrogen ion type modified smectite and a water purifying agent which are capable of collectively treating impurities as described above, and are particularly effective for treating low concentration impurities. Still another object of the present invention is to provide a method for producing a hydrogen ion-type modified smectite, which can efficiently concentrate a water slurry of smectite, and can obtain a hydrogen ion-type modified smectite useful as a water purifying agent. It is in.

[0009]

Means for Solving the Problems and Modes for Carrying Out the Invention As a result of earnest studies to achieve the above-mentioned object, the present inventor has electrophoresed a smectite slurry such as montmorillonite or bentonite containing montmorillonite as a main component. By doing so, hydrogen ion-type modified smectite is concentrated and deposited on the anode, and a gelled substance that is concentrated to about 6 to 15% (wt%, the same applies hereinafter) is obtained for monovalent ion-type smectite such as Na ⁺ type. , Ca ⁺⁺ type and other multivalent ion type smectites, it was found that a gelled substance concentrated to about 25 to 35% can be obtained. In the hydrogen ion-type modified smectite thus obtained, the pH of 1% pure water slurry is 2.5 to 4.5 and the conductivity is 12
The hydrogen ion type modified smectite showing 0 to 950 μS is capable of collectively treating and removing impurities such as colloidal substances, hardness components and organic substances contained in water, and the effect of removing impurities is, for example, 300 p
It has been found that it is effective when it contains only a low concentration of pm or less, and is therefore very effective in the secondary treatment after the primary treatment with the conventional water treatment agent.

Heretofore, as a method for obtaining hydrogen ion type clay from natural clay, there have been known methods such as dilute acid treatment, electrodialysis and treatment with H type ion exchange resin, but these methods are mainly solid. It is known as a method for obtaining an acid or activated clay. When this method is applied to bentonite or smectite, Al in the lattice is eluted and the structure is changed, and the eluted Al partially coexists with hydrogen ions. Therefore, it is said that the hydrogen ion type is not perfect ("Clay Encyclopedia", Asakura Shoten Co., Ltd., 1985).
By electrophoresis of the smectite slurry as described above, the pH of the 1% pure water slurry is 2.5 to 4.5,
Hydrogen ion-type smectite having an electric conductivity of 120 to 950 μS can be obtained, which does not cause elution of Al, does not substantially change the structure, and does not change the original properties of smectite. Impurities coexisting with smectite are removed during the electrolysis operation, so that smectite having a clean surface can be obtained.

Therefore, according to the present invention, (1) the pH of the 1% pure water slurry is 2.5 to 4.5, and the conductivity is 120 to 9.
Hydrogen ion type modified smectite with 50 μS, (2)
Provided is a method for producing a hydrogen ion-type modified smectite, comprising: (1) a water purifying agent comprising a hydrogen ion-type modified smectite; and (3) electrophoresing an aqueous slurry of smectite to collect a gel-like substance concentrated and deposited on an anode. To do.

Hereinafter, the present invention will be described in more detail.
The hydrogen ion type modified smectite of the present invention has a pH of 2.5 to 4.5 and a conductivity of 120 to 95 in a 1% pure water slurry.
It is 0 μS, which substantially maintains the structure of the raw material smectite and has the original properties of smectite.

The water purifying agent of the present invention comprises such a hydrogen ion type modified smectite. here,
If the pH of the 1% pure water slurry of this hydrogen ion-type modified smectite exceeds 4.5 and the conductivity is lower than 120 μS, the adsorbability of impurities in water is poor, and the pH is lower than 2.5 and the conductivity is 950 μS. Even if it exceeds, the adsorption capacity does not improve.

The method for producing a hydrogen ion type modified smectite of the present invention is to apply a DC electric field to an aqueous slurry of smectite to cause the smectite to electrophorese to concentrate and deposit the smectite on the anode or in the anode chamber. In this case, as the raw material smectite, monovalent ion type or polyvalent ion type montmorillonite and clay (bentonite etc.) containing montmorillonite as a main component can be preferably used. This is made into a slurry with water, and montmorillonite is concentrated and collected in the anode or the anode chamber using an electrophoresis or electrolysis device. The slurry concentration is not particularly limited as long as it is a concentration at which montmorillonite particles migrate due to an applied voltage, but in the case of Na ⁺ type smectite, which generally has a high slurry viscosity, it is about 10% or less,
In the case of Ca ⁺⁺ type smectite, which has a generally low slurry viscosity, about 30% or less is preferable for efficient concentration,
Usually, 1 to 5% slurry is preferable for Na ⁺ type, and 1 to 20% slurry is preferable for Ca ⁺⁺ type. In this case, it is also possible to add a water-soluble organic compound or the like to the slurry and concentrate it on the anode as an organic complex with smectite.

Any electrode material may be used as long as it can be used as a normal electrode, and there is no particular restriction on the shape of the electrode and the method of arranging the electrode in the slurry.

The applied DC voltage is usually 1 to several tens V / cm, and the current is not limited, but is usually 1 mA to several tens A. The temperature is not particularly limited, but room temperature is usually sufficient. Although the time is not limited, it is preferably about 1 to 10 hours.

As the water used for preparing the slurry, ion-exchanged water, tap water, etc. are used. In the present invention, smectite particles are moved by electrokinetic development, so that nonionic or cationic impurities are contained in the water. Even if included
Since the amount of impurities in the obtained smectite concentrate is small, it is not always necessary to use high-purity water.

Before applying a DC voltage for electrophoresis,
It is possible to increase the electrical conductivity of the slurry by applying an AC voltage of several V to hundreds of tens V / cm to the smectite water slurry for several minutes to several hours or by performing an ultrasonic treatment of several W to several tens W. Therefore, the slurry concentration time by electrophoresis can be shortened. This pretreatment method has a conductivity of 50 μm when the smectite slurry to be concentrated is 1%.
Effective when lower than S, 50 μS or more, especially 1
It is recommended that electrophoresis is performed at 00 μS or more.

By performing electrophoresis as described above, smectite is concentrated and deposited on the anode or in the anode chamber, so that the deposit (hydrogen ion type modified smectite) attached to and deposited on the anode is scraped out. This is a gel,
It may be used as it is, or may be dried and used as powder.

In this case, as the hydrogen ion-type modified smectite, various electrophoresis conditions can be selected and controlled to obtain a 1% pure water slurry having pH and conductivity within the above ranges.

According to the method of the present invention, a high-purity hydrogen ion type modified smectite can be obtained at a high concentration from a low concentration bentonite or smectite slurry, which is suitable as an industrial method for producing smectite. In this case, when the bentonite or smectite slurry is converted to hydrogen ion type smectite by using an electrophoresis or electrolysis tank, smectite is concentrated in a gel state on the anode, so that the drying cost is reduced and the cost as a method for concentrating the smectite slurry is reduced. Is greatly reduced. Further, it is very effective as a pretreatment process when the smectite slurry is heated and dried to obtain powdery smectite, because the drying cost is reduced. Further, since such a smectite gel is concentrated in the initial smectite slurry, there is also a cost advantage in the smectite slurry or gel transportation. Therefore, the method of the present invention can be used as a concentration for slurry or gel transportation. It is useful. Moreover, in this case, the slurry or gel obtained in the present invention has a bactericidal effect and a high storage effect.

Since the obtained modified smectite has no structural change, it has almost the same properties as ordinary purified smectite except that it is acidic, and therefore it can be effectively used for the same applications as conventional smectites. To be Furthermore, substances adhering to or adsorbed on the surface of the smectite particles in the process of electrophoresis or electrolysis are removed, and since its adsorbability is increased, it is used for removing impurities from tap water, ground water, wastewater, etc., Not only hardness components in water but also dissolved organic compounds can be adsorbed and removed.

When the hydrogen ion type modified smectite of the present invention is used as a water purification agent, a necessary amount of this is added to water to be purified, and after stirring, the smectite (water purification agent) is separated and purified. A method such as obtaining water can be adopted.

[0024]

The hydrogen ion type modified smectite of the present invention is excellent in the effect of removing impurities in water and is suitable as a water purifying agent. Further, according to the production method of the present invention, the smectite slurry can be efficiently concentrated. The hydrogen ion type modified smectite can be manufactured reliably and easily.

[0025]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Example 1] Smectite slurry (smectite 2%, containing montmorillonite as a main constituent)
Using 98% of water), a smectite gel attached to the anode was obtained by an ordinary electrophoresis apparatus. In this case, a platinum wire was used for the anode and a platinum wire was used for the cathode, and electrophoresis was performed under conditions of a current of 0.1 to 3 A and a voltage of 4 to 30V. Further, the temperature was set to 25 ° C. and the electrophoresis time was set to 2 to 10 hours to obtain smectite gels of Experiment Nos. 1 to 8.

After drying these smectite gels at 105 ° C., they were made into powders and used as samples. P of a slurry prepared by adding 1 g of a sample obtained under various electrophoresis conditions to 98 g of pure water
The H and conductivity, and the conductivity of the slurry obtained by adding 0.3 g of the sample to 299.7 g of tap water and the evaporation residue of the supernatant were examined. In this case, the evaporation residue was obtained by allowing the slurry to stand for 4 days and evaporating and drying about 150 g of the transparent supernatant at 105 ° C to dryness.
The results are shown in Table 1. For comparison, Table 1 also shows the results (Experiment No. 9) of the raw material smectite slurry used in the electrophoresis.

The conductivity of the tap water used here is 355 μm.
S (25 ° C.) and evaporation residue were 245 ppm, and from this and the results in Table 1, the following was revealed.

That is, in the case of the sample of Experiment No. 1, 1% thereof
Pure water slurry has pH = 5.39, conductivity = 93.8 μS
When added to tap water, the conductivity was slightly lower than that of tap water, but the evaporation residue increased. The pH of the 1% pure water slurries shown in Experiment Nos. 2 to 8 was 3.40.
In the case of the samples of ˜4.12 and conductivity = 226 to 123.4 μS, both conductivity and evaporation residue decreased when added to tap water. In the case of the raw material montmorillonite shown in Experiment No. 9 (Ref 1), both the conductivity and the evaporation residue increased. Therefore, from the above, the acid type (hydrogen ion type) modified smectites of Experiment Nos. 2 to 8 are in water. It was confirmed that the adsorption capacity of impurities was greatly improved.

[0030]

[Table 1]

Example 2 A smectite slurry containing montmorillonite as a main constituent was subjected to electrophoresis in the same manner as in Example 1 to give a gel-like acid type (hydrogen ion type) modified smectite (Experiment No. 10). To 14) were attached to the anode and evaluated in the same manner as in Example 1. In this case, to prepare a 1% pure water slurry and a tap water 0.1% slurry, a part of the gel was evaporated to dryness at 105 ° C., the solid concentration was determined, and the required amount was added to water. Therefore, a part of the water (about 10 g in the case of pure water and about 3 g in the case of tap water) is brought from the gel. The conductivity of tap water used is 34
6 μS (25 ° C.), the evaporation residue was 236 ppm.
The other experimental methods are the same as those for the dry powder (Table 1).
Table 2 shows the results.

From the results of the adsorption ability of the gelled acid type (hydrogen ion type) modified smectite (undried) attached to the anode in Table 2, when the raw materials of Experiment Nos. 10 to 14 were montmorillonite, they were all in tap water. Adsorbs impurities and purifies water, but in Experiment No. 10, pH = 2.59, conductivity =
In the case of 962 μS, its adsorption capacity is slightly inferior to the other cases. In addition, when the raw material shown in Experiment No. 15 (reference 2) given for comparison is saponite and Experiment No. 16
In the case where the raw material shown in (Reference 3) is hectorite, both the conductivity and the evaporation residue increase, indicating that it has no ability to purify water.

That is, based on the results of Tables 1 and 2, smectites that adsorb impurities in water and purify water are 2.5 <pH <
It was confirmed that the hydrogen ion type modified smectite prepared from montmorillonite having a conductivity of 4.5 and 120 μS <conductivity <950 μS is preferable.

[0034]

[Table 2]

Example 3 A cylindrical glass container having a diameter of 8 cm and a height of 20 cm was prepared and used as a container for electrophoresis. Two spirals having an outer diameter of about 6 cm were made using a platinum wire having a diameter of 2 mm and used as electrodes. One of these was placed on the bottom of the container, and the other one was placed at a position 5 cm above it. One electrode on the bottom surface was connected to the anode of the DC power supply, and the other electrode was connected to the cathode.

In the electrophoresis container thus prepared,
800 ml of a 2% slurry of Na ⁺ type natural smectite having a swelling power of 58 ml / 2 g was put and a DC voltage of 30 V was applied between both electrodes. In addition, ion-exchanged water was used for the preparation of the slurry.

After about 8 hours, the remaining slurry liquid was removed while the electricity was still applied, and the gelled smectite deposited on the anode was recovered.

When this gelled smectite was dried at 105 ° C. and the concentration was determined, it was 12%.

The dry smectite was pulverized to measure the whiteness, which was 78%. Since the whiteness of the smectite used as the raw material was 73%, it was confirmed that the coloring component was removed from the raw material smectite by electrophoresis and the raw material smectite was concentrated and purified.

Example 4 A 3% slurry of natural Na ⁺ type smectite having a swelling power of 42 ml / 2 g was prepared using ion-exchanged water, and electrophoretic concentration was carried out in the same manner as in Example 3. The concentration of the obtained concentrated gel-like substance was 8.2% as a result of drying at 105 ° C.

Example 5 A natural Ca ⁺⁺ type smectite powder having a particle size of 44 μm or less was added to ion-exchanged water to obtain 4%.
A slurry was prepared and subjected to electrophoretic concentration in the same manner as in Example 3. After about 14 hours, the slurry was clarified, so the slurry was removed under current application, and the gelled smectite deposited on the anode was recovered. As a result of drying at 105 ° C., the concentration of gelled smectite was 33.6%.

Example 6 The same smectite as in Example 5 was added to tap water having an electric conductivity of 210 μS at 25 ° C.,
A 4% slurry was prepared and electrophoretically concentrated in the same manner as in Example 3. After about 7 hours, the slurry was clarified, so the slurry was removed under energization, and the gelled smectite deposited on the anode was recovered. As a result of drying at 105 ° C., the concentration of gelled smectite was 28.8%.

[Example 7] A 15% slurry was prepared from the same smectite as in Example 5 and ion-exchanged water, and the slurry was put in the same vessel for electrophoresis as in Example 3 to obtain 100V.
Was applied for 30 minutes. Then, electrophoresis concentration was performed in the same manner as in Example 3. The time for electrophoretic concentration, that is, the time required for the slurry to be clarified, was 8 hours, and the concentration of the obtained gel-like smectite deposit was 32.6%.

Claims (5)

[Claims] 1. The pH of a 1 wt% pure water slurry is 2.5-.
The hydrogen-ion-type modified smectite having a conductivity of 4.5 and an electric conductivity of 120 to 950 μS. 2. A hydrogen ion type modified smectite according to claim 1, wherein the smectite raw material is montmorillonite or a clay containing montmorillonite as a main component. 3. A water purifying agent comprising the hydrogen ion-type modified smectite according to claim 1 or 2. 4. A method for producing a hydrogen ion-type modified smectite, which comprises collecting a gel-like substance concentrated and deposited on an anode by subjecting an aqueous slurry of smectite to electrophoresis. 5. The method according to claim 4, wherein an AC electric field is applied to the smectite water slurry to increase the conductivity of the slurry, and then a DC electric field is applied to cause the electrophoresis.