JPS6281478A - Sequestrant and method of sequestration - Google Patents

Abstract

PURPOSE:To provide a sequestrant capable of efficiently holding and removing metal ions contained in waste water, comprising a polyamine contg., as substituents, a particular org. acid or its salt and a dithiocarboxyl group or its salt which substitutes for an active hydrogen group of the polyamine. CONSTITUTION:A sequestrant contg., as substituents, at least one group of the formula I (wherein n is an integer of 1-4) and formula II (wherein R is CH3 or CH2COOH) or its salt and at least one dithiocarboxyl group or its salt which substitute for active hydrogen atoms of a polyamine per molecule of the polyamine. Metals can be held by adding the sequestrant together with at least one member selected from among sodium monosulfide, sodium polysulfide, and sodium hydrogensulfide to waste water to precipitate metals and remove them as flocs. The sequestrant can be obtd., e.g., by reacting a polyamine with a 1-4C monohalogenated carboxylic acid having a halogenated alkyl group or a 2-4C unsatd. carboxylic acid having an unsatd. alkyl group to introduce a group of the formula I or II thereinto and reacting the product with carbon disulfide to introduce a dithocarboxyl group thereinto.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a metal collecting agent and a metal collecting method.

[Conventional technology]

In recent years, as the pollution of rivers, oceans, etc. by wastewater from factories has become a problem, regulations to prevent pollution by wastewater have been strengthened, and it is now mandatory to keep metals contained in wastewater below a specified concentration. Teoshi.

Particularly strict regulations are placed on heavy metals that are harmful to the human body, such as mercury, cadmium, zinc, copper, and chromium. For this reason, various methods have been proposed to remove metals from water, including ion flotation and ion exchange.

Electrolytic flotation method, electrodialysis method, reverse osmosis method or slaked lime,
A known method is a neutralization coagulation-sedimentation method in which metals are turned into hydroxides by adding an alkali neutralizing agent such as caustic soda, and then removed by coagulation and precipitation using a polymer flocculant. Furthermore, it is also known to use a metal scavenger to insolubilize metal ions in wastewater and remove them by precipitate.This type of metal scavenger includes monoamines such as dialkyl monoamine and diphenyl monoamine that contain one ion per chlorine atom. A dithiocarbamic acid compound having a structure in which dithiocarboxylic groups of
0), a compound having a structure obtained by addition polymerization of a compound having two acryloyl groups and an amino acid having two hydrogen atoms bonded to a nitrogen atom (Japanese Patent Publication No. 10999/1983), etc. are known.

[Problem that the invention seeks to solve]

However, ion flotation method and ion exchange method.

The electrolytic flotation method, electrodialysis method, and reverse osmosis method have problems such as the removal rate of heavy metals, operability, and running costs, and currently they are only used for some special wastewater treatments. In addition, the neutralization coagulation-sedimentation method produces a large amount of metal hydroxide sludge, and these hydroxide sludges have poor dewatering properties and large sludge volumes, making it difficult to transport. It is also extremely difficult to remove wastewater below the wastewater standard value. Moreover, depending on how these sludges are disposed of, they may be redissolved and cause secondary pollution. Furthermore, JP-A-51-14036
The metal collector described in No. 0 and Japanese Patent Publication No. 54-10999 had a problem with the bonding force with metal ions, and the removal rate of gold scrap ions from wastewater was not sufficient.

[Failure to solve the problem]

This is the result of intensive research by the inventors in view of the above points.

-(CHz)n substituted with active hydrogen atom of polyamines
-COOH group (n is an integer of 1 to 4), -CH
zCH(CHs)COOH,-CH2CM(CHz C
0OH) A polyamine derivative having at least one C0OH or a salt thereof and a dithiocarboxy group or a salt thereof per polyamine molecule has an excellent metal scavenging ability, and furthermore, the polyamine derivative and sodium monosulfide, The present invention was completed by discovering that metal ions in wastewater can be efficiently collected and removed by adding at least one of sodium polysulfide and sodium hydrogen sulfide to wastewater in combination.

That is, one of the gist of the present invention is that per molecule of polyamines,
At least one substituted with an active hydrogen atom of the polyamines
-(C)n-COOH groups (where n is an integer of 1 to 4), -CHz CHRCOOH (however, R is CH
z or CH, COOH) or salts thereof, and at least one dithiocarboxy group or a salt thereof as all substituents. Another aspect of the present invention is that, per polyamine molecule, at least one -(CHz)n C0OH group substituted with an active hydrogen atom of the polyamine (where n is 1 to
4 integer), -CHICHRCOOH (but RF
i, CHs or CHt COOH) or a salt thereof, a metal scavenger having at least one dithiocarboxy group or a salt thereof as a substituent, and sodium monosulfide or sodium polysulfide.

The present invention provides a metal collection method characterized by adding at least one kind of sodium hydrogen sulfide to wastewater containing metal ions to collect and remove metal ions in the wastewater.

The metal scavenger of the present invention is prepared by reacting, for example, a polyamine with a monohalogenated carboxylic acid having 1 to 4 carbon atoms in a halogen-substituted alkyl group or an unsaturated carboxylic acid having 2 to 4 carbon atoms in an unsaturated alkyl group. Te(CHs) n
C0OH group, -CHz CH(CHs) C0OH
Group or 10Hz CH (CHs C0OH) C0
After introducing an OH group, react with carbon disulfide to introduce a dithiocarboxy group, or react with carbon disulfide to introduce a dithiocarboxy group, then react with a monohalogenated carboxylic acid or an unsaturated carboxylic acid. At least - (CH,).

-COOH group, CH2CH(CHs) C0OH
Group or -CH! CH-(CHz C0OH) C
This can be obtained by introducing an 0OH group.

The above-mentioned polyamines are compounds having two or more imino groups or amine groups in which one or two active hydrogen atoms are bonded to a nitrogen atom.For example, ethylene diamine, globylene diamine, butylene diamine, hexamethylene diamine. , diethylenetriamine, diglopylenetriamine, dibutylenetriamine, triethylenetetramine, tripropylenetetramine, tributylenetetramine.

Polyalkylene polyamines such as tetraethylene pentamine, tetrapropylene pentamine, tetrabutylene pentamine, pentaethylene hexamine; aniline, phenylene diamine, xylene diamine, metaxylene diamine, iminobispropylamine, monomethylaminoglobilamine, methyliminobis Propylamine, 1.3
-bis(aminomethyl)cyclohexane, 1,3-diaminopropane, 1,4-diaminobutane, 3,5-diaminochlorobenzene, melamine, 1-aminoethylpiperazine, piperazine, diaminophenyl ether, 3.
Examples include 3'-dichlorobenzidine, tolidine paste, m-)lylene diamine, and ethylene polyimine (average molecular weight of 300 or more). In addition to the above polyamines, N-alkyl polyamines, N-hydroxyalkyl polyamines, N-acyl polyamines, etc. obtained by reacting these polyamines with alkyl halides, epoxy alkanes, or fatty acids may be used. You can also do it. N-alkylethylenediamine is the N-alkylpolyamine.

N-furkylpropylene diamine, N-alkylhexamethylene diamine, N-alkylphenylene diamine,
N-alkylxylene diamine, N-alkyldiethylenetriamine, N-alkyltriethylenetetramine,
N-alkyltetraethylenepentamine, N-alkylpentaethylenehexamine, etc. can be used. The number of carbon atoms in the N-substituted alkyl group is preferably 2 to 18.

The hydroxyalkyl group of the N-hydroxyalkyl polyamine preferably has 2 to 28 carbon atoms, and examples of the hydroxyalkyl group include hydroxyethyl group, hydroxypropyl group, hydroxybutyl group, β-hydroxydodenyl group, β-hydroxytetradecyl group. group, β-hydroxyhexadecyl group, β-hydroxyoctadecyl group, β-hydroxyoctacosyl group, and the like. In addition, the acyl group of N-acylpolyamine has 2 to 2475 carbon atoms.
X is preferred, and the acyl group is, for example, an acetyl group.

Glopionyl group, butyryl group, caproyl group, lauroyl group, oleoyl group, myristyroyl group.

Examples include stearoyl group and beheroyl group.

Furthermore, these polyamines and epichlorohydrin.

Polycondensed polyamines obtained by polycondensation with shrimp halohydrin such as shrimp bromohydrin, shrimp iodohydrin, and bromomethyloxiran can also be used.

These polyamines can be used alone or in combination of two or more.

Examples of monohalogenated carboxylic acids and unsaturated carboxylic acids to be reacted with the polyamines include monochloroacetic acid, monochloropropionic acid, monochlorobutyric acid, acrylic acid, methacrylic acid, and itaconic acid.

The metal scavenger of the present invention has the above -(CHz) n Coo
n group.

-CHz CH(CI(t)eoOH group is -C
In addition to those having an Eh CH (CHh C00H)eoOH group as a substituent, those having salts of these as a substituent may also be used. Examples of the salts include alkali metal salts such as potassium salts, sodium salts, and lithium salts; alkaline earth metal salts such as calcium salts, magnesium salts, and barium salts; and ammonium salts. Methods for introducing substituents having these groups include a method in which the above-mentioned halogenated carboxylic acid or unsaturated carboxylic acid salt is reacted with polyamines, (CH
2) After introducing an acid type substituent such as n-C0OH group, alkali metal hydroxide, alkaline earth metal hydroxide,
Should it be treated with an alkali such as ammonia?

Alternatively, there may be mentioned a method in which a reaction between a halogenated carboxylic acid or an unsaturated carboxylic acid and a polyamine is carried out in the presence of an alkali. Furthermore, in producing the metal scavenger of the present invention, the halogenated carboxylic acid.

It is also possible to use a lower alcohol ester such as methyl acrylate as a substitute for an unsaturated carboxylic acid or a salt thereof, and to convert it into an acid type substituent or its salt by saponification, acid decomposition, etc.

The metal scavenger of the present invention may have a salt of a dithiocarboxy group as a substituent on the dithiocarboxy group. As the salt of dithiocarboxy group, -(CHz)
Similar to salts such as n C0OH groups, alkali metal salts, alkaline earth metal salts, and ammonium salts can be mentioned. Examples of methods for introducing a salt of a dithiocarboxy group as a substituent include reacting with carbon disulfide to introduce a dithiocarboxy group, and then treating with an alkali, or reacting with carbon disulfide in the presence of an alkali. It will be done.

The above -(CHx)n-C0OH group, GHz
CH(CHs)C0OH group.

CHx CH(CHs C0OH) The C0OH group or its salts and the dithiocarboxy group or its salts are usually N-substituents bonded to the nitrogen atom of polyamines, but when bonded to epino-10 hydrin as polyamines However, the hydrogen atom may be substituted with a hydrogen atom of a hydroxyl group occurring in the epino-rohydrin skeleton, and may be bonded to an oxygen atom.

The metal collecting method of the present invention is a method in which the metal collecting agent of the present invention and at least one of sodium monosulfide, sodium polysulfide, and sodium hydrogen sulfide are added to wastewater, and the mixture is precipitated and removed as flocs. The metal scavenger of the present invention has an excellent bonding force with metal ions and a high metal ion removal rate, but it is difficult to use in combination with sodium sulfides such as sodium monosulfide, sodium polysulfide, and sodium hydrogen sulfide.

The flocs produced are large, the time required for sedimentation of the flocs can be shortened, and metal ions in wastewater can be removed extremely efficiently and reliably.

In addition, sodium sulfides also have the ability to form complexes with metal ions, but when used alone, the flocs produced are extremely small, making it difficult to precipitate and remove the flocs. Only when used together will the floc settling time be shortened.

Moreover, efficient wastewater treatment with excellent metal ion removal rate can be performed. This is considered to be because the ability of the metal scavenger of the present invention to form a complex with metal ions and the ability of the sodium sulfide to form a complex with metal ions act synergistically. The amount of metal scavenger and sodium sulfide added to wastewater is usually 0.8 to 4.0 equivalents of the amount of metal ions in wastewater as the total amount of both, but in particular 1.0 to 1.5 equivalents. The amount is preferable.

In the present invention, even if IJum (monosulfide), sodium polysulfide, or sodium hydrogen sulfide is used in combination, the sedimentation time of the generated flocs can be shortened, and efficient wastewater treatment can be performed.

In particular, when sodium polysulfide or sodium hydrogen sulfide is used, the settling properties of flocs become even better, and the most efficient wastewater treatment can be performed.

Sodium polysulfide is sodium disulfide.

Sodium trisulfide, imaging sodium, and sodium trisulfide are used. The purpose of the present invention can be achieved if the ratio of the metal scavenger of the present invention to sodium sulfides is 1:99 to 99:1 by weight.

In particular, the ratio is preferably 20:80 to 98:2.

The metal scavenger and sodium sulfide may be mixed in advance and added to the wastewater, or they may be added to the wastewater separately.
It is preferable to mix the two in advance and add the mixture to the wastewater. In addition, when added separately.

The metal ion removal effect is almost the same whether IJium is added (adding the metal scavenger first and then sulfurizing) or adding it in the reverse order.

In the present invention, when collecting and removing metal ions in wastewater, the pH of the wastewater is adjusted to 3 to 10. In particular, it is preferable to adjust it to 4-9. The acid or alkali used to adjust the pH may be anything as long as it does not inhibit the formation of flocs.9 Usually, the acid used is hydrochloric acid, sulfuric acid, nitric acid, etc.
As alkalis, sodium hydroxide, potassium hydroxide,
Calcium hydroxide etc. are used.

According to the method of the invention, mercury, cadmium, zinc.

Lead, copper, chromium, arsenic, gold, silver, platinum, vanadium, thallium, etc. can be efficiently collected and removed.

〔Example〕

Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 43.2 g of ethylenediamine and 576 g of an aqueous solution of 20% hydroxide were placed in a four-way flask equipped with a stirrer, a thermometer, 9 dropping funnels, and a reflux condenser, and the mixture was heated to 40°C with vigorous stirring through the dropping funnel. carbon sulfide 54.
After dropping 1 drop of 7.9.

Aging was performed at the same temperature for 4 hours. Next, sodium monochloroacetate 167.8.9 was added and the reaction was carried out at 60 to 80°C for 7 hours, then the 9 reaction solution was poured into a large amount of acetone to form a precipitate, and the precipitate was reconstituted in a water-acetone system. Purify by performing precipitation three times and dry under reduced pressure to obtain -CHx COO
A metal scavenger 262.6.9 having a sulfur content of 24.1 wt% and having Na groups and -C8SNa groups as substituents was obtained.

Next 1c Cu, Hg each i o o xg7
The above metal scavenger was added in an amount of 40 mg per 1 volume of the two types of aqueous solutions containing 85% and 9%. 125Q, 16
511F was added and stirred for 10 minutes, the precipitate was separated and the Cu and Hg remaining in each solution were measured. I asked for the quantity. The results are shown in Table 1.

Add hydrogen sulfide to 100g of the above metal scavenger) IJium 50
126 g of the mixture was mixed with a copper ion-containing aqueous solution (5
0- Cu content, pH=5.0), cadmium ion-containing aqueous solution (50F Cd content, p)
i=5. Q).

Mercury ion-containing aqueous solution (contains 50P of Hg2+, pH
=5.0).

Lead ion-containing aqueous solution (sop pb content, pH
= 5.0) were added to 1000 d each,
After stirring for 5 minutes, the mixture was allowed to stand and the time required for the generated flocs to settle was measured. The results are shown in Table 1.

Next, after the generated flocs were filtered, the concentration of residual metal ions in the filtrate was measured by atomic absorption spectrometry. The results and the volume of the generated flocs are also shown in Table 1.

Example 2 Triethylenetetramine 74% was placed in the same apparatus as in Example 1.
9.9 and 23% sodium hydroxide 535.3. 78 g of carbon disulfide was reacted in the same manner as in Example 1. Next, 268.8 g of monochloropropionic acid was added and the reaction was carried out at 80 to 90°C for 6 hours, followed by purification and drying in the same manner as in Example 1.

-CHs Metal scavenger with CH2COONa group and -C8SNa group with sulfur content of 17.1 wt% 334.
3 g was obtained.

Table 1 shows the results of the amount of Cu and Hg collected by this metal collector II (equivalent to metal collector II) determined in the same manner as in Example 1.

This metal scavenger is 100.9% and sodium disulfide is 50%!
115 mfi of the mixture containing i+ was added to each of 1000 NIK of the same four metal ion-containing aqueous solutions as in Example 1, and the floc precipitation time, floc production amount, and residual metal ion concentration in the filtrate were measured in the same manner as in Example 1. did. The results are shown in Table 1.

Example 3 346.9# of water was charged into the same apparatus as in Example 1.

Next, 48.2 # of hexamethylene diamine was finely ground and dispersed in water, and then 64 # of carbon disulfide was dissolved at 40°C.
．． 3,! After adding 9 drops of i', the mixture was aged at the same temperature for 2 hours. Next, 82-9 g of methyl methacrylate was added and the reaction was carried out at 70-80°C for 5 hours.

After the reaction was completed, 2N hydrochloric acid 4231 was added and maintained at 95-100°C for 8 hours. The reaction solution was poured into a large amount of acetone, the resulting precipitate was purified and dried in the same manner as in Example 1, and -C
A metal scavenger having a sulfur content of 28.7 wt% and having a CH(CHs)COOH group and a -C8SH group as substituents was obtained. Table 1 shows the amounts of Cm and Hg captured by this metal collector II.

Mixture 12311 in which sodium hydrogen sulfide 209 and sodium disulfide 20.9 are mixed with metal scavenger 1005
9 was added to the same aqueous solution 1 containing four metal ions as in Example 1.
000 m, and the floc sedimentation time and floc production amount were determined in the same manner as in Example 1.

The residual metal ion concentration in the filtrate was measured. The results are shown in Table 1.

Example 4 Polycondensation polyamine 11 obtained by polycondensing 74.3 g of diethylenetriamine with 66.7 g of epichlorohydrin
4.6. l water 86.5g, 33% sodium hydroxide 43
7 g was charged into the same apparatus as in Example 1.

Carbon disulfide 109.6.9 was added dropwise through a dropping funnel at 40°C. After 1 drop, it was aged at the same temperature for 10 hours. After carrying out the reaction for a time, Example 1
Purify and dry in the same manner.

-CHz Metal scavenger 3 with sulfur content of 20.1 wt% having COONa group and -C8SNa group as substituents
94.59 was obtained. C12+ per gram of this metal scavenger
, The amount of Hg2+ collected is shown in Table 1.

A mixture 11011iJ of this metal collector 100F mixed with 40p of imaging sodium was added to each of the four metal ion-containing aqueous solutions 1000117 as in Example 1,
In the same manner as in Example 1, floc settling time, floc production amount, and residual metal ion concentration in the filtrate were measured. The results are shown in Table 1.

Example 5 Phenyldiamine 98, 79 was added to the same apparatus as in Example 1.
and x+8.8.9 water-acetone (1:1) and 43%
Add 340g of IJum aqueous solution,
Carbon disulfide at ℃ is 104.2! Press in i.

The reaction was carried out at the same temperature for 6 hours. Then sodium monochlorobutyrate 266.2,! Add i', 60-80
After reacting at ℃ for 7 hours, it was purified and dried in the same manner as in Example 1 to obtain a metal scavenger with a sulfur content of 20.4 wt% having 10H COONa group and -C8SNa group as substituents. I got a score of 9.9. C of this metal scavenger 1y
Table 1 shows the amount of u'', Hg''+ collected.

12,011 g of a mixture of 40 g of sodium hydrogen sulfide mixed with 100 p of this metal scavenger was added to each of 10,100 O of the same four metal ion-containing aqueous solutions as in Example 1, and the floc precipitation time and floc production amount were determined in the same manner as in Example 1. ,
The residual metal ion concentration in the filtrate was measured. The results are shown in Table 1.

Example 6 N-Probilt IJ ethylenetetramine 104.5# and 27.3% aqueous sodium hydroxide solution 416.0.9 were charged in the same apparatus as in Example 1, and carbon disulfide 84.0 was prepared in the same manner as in Example 1. 5 g was reacted. Sodium monochlorobutyrate 282.9 II was then added and 70-8
After reacting at 0°C for 8 hours, purification and drying were performed in the same manner as in Example 1 to obtain -CHx CHz COONa group and -C8S
Sulfur content with Na group as a substituent: 14.9 wt
% metal scavenger was obtained. Table 1 shows the amounts of Cu" and Hg"+ collected per gram of this metal trapping agent.

A mixture of 100 g of this metal scavenger and 50 g of sodium disulfide (1051 lI9) was added to the same four metal ion-containing aqueous solutions as in Example 1. Each was added to QQQd, and the floc precipitation time, floc production amount, and residual metal ion concentration in the filtrate were measured in the same manner as in Example 1. Results first
Shown in the table.

Example 7 120 W+g of a mixture of 100 p of the same metal scavenger as in Example 5 and 40 y of sodium monosulfide was added to 1000 g of the same four metal ion-containing aqueous solutions as in Example 1, and In the same manner, floc precipitation time, floc production amount, and residual metal ion concentration in the filtrate were measured. The results are shown in Table 1.

Example 8 A mixture of 105 ml and 50.9 ml of the same metal scavenger 10011K sodium monosulfide as in Example 6 was added to each of the four metal ion-containing aqueous solutions 1000117 as in Example 1. In the same manner as above, floc precipitation time, floc production amount, and residual metal ion concentration in the filtrate were measured. The results are shown in Table 1.

Comparative Example 1 Sodium diethyldithiocarbamate 132μ was added to 10100O of the same aqueous solution containing four metal ions as in Example 1.
and floc sedimentation time in the same manner as in Example 1.
The amount of flocs produced and the concentration of residual metal ions in the filtrate were measured. The results are shown in Table 1. Table 1 shows the results of determining the amount of Cu", Hg"+ collected per gram of sodium diethyldithiocarnocimate in the same manner as in Example 1.

〔Effect of the invention〕

As explained above, the metal scavenger of the present invention has at least one -(CHz
) n Coon group, -cx ctut C0OH
By having a group or a salt thereof and at least one dithiocarboxy group or a salt thereof as a substituent, the binding force with metal ions is higher than that of conventional metal scavengers, making it an excellent agent. It has the ability to collect metal ions. In addition, the metal collecting method of the present invention employs a method in which the above-mentioned metal collecting agent and at least one of sodium monosulfide, sodium polysulfide, and sodium hydrogen sulfide are added to wastewater). It has the effect of reducing the time required for sedimentation of flocs, and collecting and removing metal ions in wastewater extremely efficiently and reliably.

Claims (2)

[Claims] (1) At least one -(CH_2)_ substituted with an active hydrogen atom of the polyamine per molecule of the polyamine.
n-COOH group (where n is an integer of 1 to 4), -CH_
2CHRCOOH (R is CH_3 or CH_2C
OOH) or a salt thereof, and at least one dithiocarboxy group or a salt thereof as a substituent. (2) At least one -(CH_2)_ substituted with an active hydrogen atom of the polyamine per molecule of the polyamine.
n-COOH group (where n is an integer of 1 to 4), -CH_
2CHRCOOH (R is CH_3 or CH_2C
OOH) or these salts, a metal scavenger having at least one dithiocarboxy group or a salt thereof as a substituent, and at least one of sodium monosulfide, sodium polysulfide, and sodium hydrogen sulfide to collect metal ions. A method for collecting metals, which is characterized in that metal ions in the wastewater are collected and removed by adding the metal ions to the wastewater contained therein.