JPH057079B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a metal collection method. [Prior art] 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 metals contained in wastewater must be kept below a specified concentration. It is mandatory that
Particularly strict regulations are in place for 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 wastewater, including ion flotation, ion exchange, electrolytic flotation, electrodialysis, reverse osmosis, 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. [Problems to be solved by the invention] However, ion flotation, ion exchange,
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 precipitation method produces a large amount of metal hydroxide sludge, and these hydroxide sludges have problems such as poor dewatering properties and large sludge volumes, making it difficult to transport. It is also very difficult to remove it below the standard value. Moreover, depending on how these sludge is disposed of, there is also the problem that it may re-melt and cause secondary pollution. [Means for Solving the Problems] The present inventors have conducted extensive research in view of the above points, and have found that at least one β-hydroxyalkyl group and at least one dithiocarboxy group or a salt thereof in one molecule. It was discovered that a polyamine derivative having as an N-substituent has excellent performance as a metal scavenger, but as a result of further intensive research, the above polyamine derivative and sodium monosulfide,
The present invention was completed based on the discovery that metal ions in wastewater can be most efficiently collected and removed by using together at least one of sodium polysulfide and sodium hydrogen sulfide. The metal collection method of the present invention includes at least one β-hydroxyalkyl group and at least one dithiocarboxy group or a salt thereof in one molecule.
- This is a method of collecting and removing metal ions in wastewater by adding a polyamine derivative as a substituent and at least one of sodium monosulfide, sodium polysulfide, and sodium hydrogen sulfide to wastewater containing metal ions. The polyamine derivative used in the present invention is 1
At least one β substituent substituted with the active hydrogen bonded to the nitrogen atom in the polyamine molecule having a primary amino group and/or a secondary amino group
-A compound having a hydroxyalkyl group and at least one dithiocarboxy group: -CSSH or its salts, such as alkali metal salts such as sodium salts and potassium salts, alkaline earth metal salts such as calcium salts, ammonium salts, etc. It is. This polyamine derivative has, for example, at least one β-hydroxyalkyl group obtained by ring-opening addition of an epoxy alkane to a polyamine as an N-substituent, and at least one β-hydroxyalkyl group bonded to a nitrogen atom.
At least one active hydrogen compound obtained by reacting a poly(or mono)-N-(β-hydroxyalkyl)polyamine with carbon disulfide, or by reacting polyamines with carbon disulfide. Ring-opening addition of an epoxy alkane to a compound having a dithiocarboxy group as an N-substituent and at least one active hydrogen bonded to a nitrogen atom, that is, a poly(or mono)-N-(dithiocarboxy)polyamine After the completion of the reaction, the active hydrogen of the dithiocarboxy group can be converted into an alkali by treating with an alkali such as sodium hydroxide, potassium hydroxide, or ammonium hydroxide, or by performing the above reaction in the presence of an alkali. metals, alkaline earth metals,
It can be substituted with ammonium or the like. Furthermore, a polyamine derivative having a dithiocarboxy group and a salt of a dithiocarboxy group as a substituent can be obtained by substituting a part of the active hydrogen of the dithiocarboxy group with an alkali metal, an alkaline earth metal, ammonium, or the like. The poly(or mono)-N-(β-hydroxyalkyl)polyamine and carbon disulfide are reacted in a solvent, preferably water or alcohol, for 30 to 30 minutes.
It is preferable to carry out the reaction at 100°C for 1 to 10 hours, particularly at 40 to 70°C for 2 to 5 hours. Also poly (or mono)
The reaction between the N-(dithiocarboxy)polyamine and the epoxy alkane is carried out at 40 to 100°C in a solvent, preferably water, alcohol, acetone, dioxane, methyl ethyl ketone, etc. alone or in a mixed solvent.
It is preferably carried out for 1 to 19 hours, particularly in a 1:1 mixed solvent of water and acetone at 60 to 80°C for 2 to 3 hours. Examples of the above polyamines include ethylene diamine, propylene diamine, butylene diamine, hexamethylene diamine, diethylene triamine, dipropylene triamine, dibutylene triamine, triethylene tetramine, tripropylene tetramine, tributylene tetramine, tetraethylene pentamine, and tetrapropylene pentamine. , polyalkylene polyamines such as tetrabutylene pentamine, pentaethylene hexamine; ) Cyclohexane, 3,5-diaminochlorobenzene, melamine, 1-aminoethylpiperazine, piperazine, 3,3'-dichlorobenzidine, diaminophenyl ether, tolidine, m-tolylenediamine, etc., and polyethylene polyimine (average molecular weight 300 or more) ) etc. are used. Furthermore, N-substituted polyamines having an alkyl group, acyl group, etc. as a substituent, such as N-alkyl polyamine and N-acyl polyamine, can also be used. These N-substituted polyamines can be obtained by reacting the polyamines with alkyl halides and fatty acids. As the N-alkyl polyamine, for example, N
-Alkylethylenediamine, N-alkylpropylenediamine, N-alkylhexamethylenediamine, N-alkylphenylenediamine, N-
Alkylxylene diamine, N-alkylethylenetriamine, N-alkyltriethylenetetramine, N-alkyltetraethylenepentamine,
Examples include N-alkylpentaethylenehexamine, and the number of carbon atoms in the N-substituted alkyl group is 2 to 18.
is preferred. The above polyamines and N-substituted polyamines can be used alone or in combination of two or more. At least one β-
The β-hydroxyalkyl group in the polyamine derivative having a hydroxyalkyl group and at least one dithiocarboxy group or a salt thereof as a substituent has preferably 2 to 28 carbon atoms, and a preferable epoxy group for introducing the β-hydroxyalkyl group is Alkanes have 2 to 28 carbon atoms. Examples of the above-mentioned epoxy alkanes include ethylene oxide, propylene oxide, bitylene oxide, and α-olefin oxide (with 6 to 6 carbon atoms).
28) etc. In the method of the present invention, a polyamine derivative having at least one β-hydroxyalkyl group and at least one dithiocarboxy group as an N-substituent, and at least one of sodium monosulfide, sodium polysulfide, and sodium hydrogen sulfide are used. is added to wastewater to collect and remove metal ions from the wastewater. As the sodium polysulfide, sodium disulfide, sodium trisulfide, sodium tetrasulfide, and sodium pentasulfide are used. The purpose of the present invention can be achieved if the weight ratio of the polyamine derivative to the above-mentioned sodium sulfides is 1:99 to 99:1, but it is particularly preferably 20:80 to 98:2.
The polyamine derivative and the sodium sulfides may be mixed in advance and added to the wastewater, or they may be added to the wastewater separately, but it is preferable to mix them in advance and add them to the wastewater. In addition, when adding them separately, the metal ion removal effect is almost the same whether the polyamine derivative is added first and then the sodium sulfides are added, or the metal ion removal effect is added in the reverse order. The polyamine derivative used in the present invention can be used alone as a metal scavenger, but when used in combination with sodium sulfide, the generated flocs are even larger, the time required for sedimentation of flocs can be shortened, and metal ions in wastewater can be used. can be collected and removed extremely efficiently. 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 the flocs and remove them.
Metal ions in wastewater can be efficiently collected and removed only when used in combination with the polyamine derivative. This is thought to be due to the synergistic effect of the ability of polyamine derivatives to form a complex with metal ions and the ability of sodium sulfides to form a complex with metal ions. Therefore, the amount of polyamine derivatives and sodium sulfides added to wastewater is 0.7 to 4 molar equivalent of the amount of metal ions in wastewater as the total amount of both,
Particularly preferred is an amount of 0.9 to 1.5 molar equivalents. In the present invention, when collecting and removing metal ions in wastewater by adding polyamine derivatives and sodium sulfides to wastewater, it is preferable to adjust the pH of the wastewater to 3 to 10, particularly 4 to 9. The acid or alkali used to adjust the pH may be anything as long as it does not inhibit the formation of flocs, but the acids usually used are hydrochloric acid, sulfuric acid, nitric acid, etc., and the alkalis include sodium hydroxide, potassium hydroxide, Calcium hydroxide etc. are used. According to the method of the present 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 by giving examples. Example 1 In a four-necked flask equipped with a stirrer, thermometer, dropping funnel, and reflux condenser, 106 g of N-(β-hydroxylauryl)ethylenediamine and 90 g of a 20% aqueous sodium hydroxide solution were charged and heated vigorously at 40°C. While stirring, 33 g of carbon disulfide was added dropwise from the dropping funnel, and after the addition was completed, aging was carried out at the same temperature for 4 hours. Next, the reaction solution was poured into a large amount of acetone to form a precipitate, and the precipitate was purified by reprecipitation three times in a water-acetone system, and then dried under reduced pressure to obtain a polyamine derivative powder with a sulfur content of 17.5 wt%. 125g
I got it. 0.3 g of a mixture of 100 g of this polyamine derivative and 30 g of sodium monosulfide was added to an aqueous solution containing copper ions (containing 50 ppm Cu ²⁺ , PH = 5.0), an aqueous solution containing cadmium ions (containing 50 ppm Cd ²⁺ , PH =
5.0), aqueous solution containing mercury ions (containing 50ppm Hg ²⁺ , PH=5.0), aqueous solution containing lead ion (containing 50ppm Hg 2+, PH=5.0),
1000ml each of 4 types of aqueous solutions containing Pb ²⁺ (PH=5.0)
After stirring for 5 minutes, the time required for the flocs to settle was measured. The results are shown in Table 1. After the produced flocs were then filtered, the concentration of residual metal ions in the filtrate was measured by atomic absorption spectrometry. The results and the volumes of the produced flocs are also shown in Table 1. Example 2 In the same apparatus as in Example 1, 118 g of N-(β-hydroxyoctyl)triethylenetetramine and
180 g of a 20% aqueous sodium hydroxide solution was charged, and 66 g of carbon disulfide was reacted in the same manner as in Example 1, followed by purification and drying to obtain 195 g of a pale yellow polyamine derivative powder with a sulfur content of 26.8 wt%. 0.3 g of a mixture of 100 g of this polyamine derivative and 30 g of sodium pentasulfide was added to 1000 ml of the same four metal ion-containing aqueous solutions as in Example 1, and the floc precipitation time, floc production amount, The residual metal ion concentration in the filtrate was measured. The results are shown in Table 1. Example 3 In a device similar to Example 1, N,N-bis(β
-Hydroxyoctyl)triethylenetetramine
173g and 360g of 20% sodium hydroxide aqueous solution were charged, and then 66g of carbon disulfide was added in the same manner as in Example 1.
were reacted, purified and dried to obtain 286 g of pale yellowish white polyamine derivative powder with a sulfur content of 19.1 wt%. 0.4 g of a mixture of 100 g of this polyamine derivative and 20 g of sodium hydrogen sulfide was added to 1000 ml of the same four metal ion-containing aqueous solutions as in Example 1. , the residual metal ion concentration in the filtrate was measured. The results are shown in Table 1. Example 4 In the same apparatus as in Example 1, 167 g of N-(β-hydroxyhexadecyl)diethylenetriamine and water were added.
Prepare 200g and heat to 60℃ to produce 44g of carbon disulfide.
was added dropwise from the dropping funnel, and after the addition was completed, aging was carried out at the same temperature for 4 hours. Then the reaction solution was heated to 70-75
The temperature was raised to .degree. C., 120 g of 20% sodium hydroxide was added, and the reaction was carried out for 1.5 hours. After that, Example 1
Refined and dried in the same manner as above, resulting in a sulfur content of 15.7wt.
% of pale reddish brown polyamine derivative powder was obtained. A mixture of 100g of this polyamine derivative, 20g of sodium monosulfide and 15g of sodium pentasulfide.
0.3 g was added to 1000 ml 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. The results are shown in Table 1. Example 5 429 g of water was charged into the same apparatus as in Example 1, and then 299 g of N-(β-hydroxyoctacosyl)hexamethylenediamine was finely ground and dispersed in water, and then carbon disulfide was added at 40°C. 47 g was added dropwise, and after the addition was completed, it was aged at the same temperature. then 30
% aqueous sodium hydroxide solution was added, the temperature was raised to 50°C, and the reaction was carried out for 1.5 hours. After the reaction is complete, insoluble components are filtered out and washed with water, then with acetone, crushed and dried under reduced pressure to obtain a sulfur content of 12.5wt%.
306 g of a yellow polyamine derivative was obtained. 0.4 g of a mixture of 100 g of this polyamine derivative and 20 g of sodium monosulfide was added to 1000 ml of the same four metal ion-containing aqueous solutions 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. Example 6 99 g of commercially available polyethylene polyimine (manufactured by Nippon Shokubai Kagaku Kogyo Co., Ltd., Epomin SP-300) was dissolved in 146 g of ethyl alcohol, and 212 g of epoxy alkane (carbon number 12) was added under reflux while heating to 75°C and stirring. After dropping, the mixture was kept at the same temperature for 2 hours and then concentrated to obtain 231 g of a yellow crystalline solid. 200 g of this crystalline solid was finely ground and dispersed in 200 g of water, 20 g of sodium hydroxide was added, and 32 g of carbon disulfide was added dropwise at 40°C. After the dropwise addition was completed, the reaction was continued at the same temperature for 2 hours. After the reaction, insoluble components were filtered off and washed with water, further washed with acetone, and dried under reduced pressure to obtain 241 g of a yellow pulverized polyamine derivative having a sulfur content of 10.1 wt%. 0.3 g of a mixture of 100 g of this polyamine derivative and 30 g of sodium pentasulfide was added to 1000 ml of the same four metal ion-containing aqueous solutions 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. Example 7 200 g of the same crystalline solid as in Example 6, in which polyethyleneimine was reacted with an epoxy alkane, was dissolved in 58 g of concentrated ammonia water, then dispersed in 300 g of water, and 32 g of carbon disulfide was added dropwise at 40°C. After the dropwise addition was completed, the reaction was continued at the same temperature for 2 hours. After the reaction was completed, insoluble components were filtered off, washed with water, further washed with acetone, and dried under reduced pressure to obtain 239 g of a yellow pulverized polyamine derivative having a sulfur content of 10.86 wt%. A mixture of 100g of this polyamine derivative, 15g of sodium monosulfide and 15g of sodium pentasulfide.
0.3 g was added to 1000 ml 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. The results are shown in Table 1. Example 8 100 g of the polyamine derivative obtained in Example 6 was added to 200 g of water.
Then, 24 g of ammonium chloride was added and the reaction was carried out at 50°C for 4 hours. After the reaction, insoluble components were filtered out and washed with water, and then with acetone.
Sulfur content 11.5wt%, obtained by drying under reduced pressure and replacing the active hydrogen of the dithiocarboxy group with ammonium.
95 g of a yellow polyamine derivative was obtained. 0.3 g of a mixture of 100 g of this polyamine derivative and 30 g of sodium hydrogen sulfide was added to 1000 ml of the same four metal ion-containing aqueous solutions as in Example 1. , the residual metal ion concentration in the filtrate was measured. The results are shown in Table 1. Example 9 100g of sodium salt of N-(dithiocarboxy)ethylenediamine and epoxyalkane (carbon number
12) 116.5g and 500g of water-acetone (1:1)
After the reaction was completed, the reaction solution was poured into a large amount of acetone to form a precipitate, and the precipitate separated by filtration was reprecipitated in a water-acetone system for 3 hours.
The sulfur content is 17.6% after being purified and dried under reduced pressure.
165 g of light brown polyamine derivative powder was obtained. 0.3 g of a mixture of 100 g of this polyamine derivative and 30 g of sodium monosulfide was added to 1000 ml of the same four metal ion-containing aqueous solutions 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. Example 10 In the same apparatus as in Example 1, 120.6 g of sodium salt of N,N,N'-tris(dithiocarboxy)phenylenediamine and epoxy alkane (carbon number 12) were added.
After charging 55.2 g and 500 g of water-acetone (1:1) and carrying out a reaction at 80°C for 4 hours, the reaction solution was poured into a large amount of acetone to form a precipitate.
The filtered precipitate was purified in the same manner as in Example 9 and dried under reduced pressure to obtain 170.5 g of a light brown polyamine derivative powder with a sulfur content of 32.76 wt%. 0.3 g of a mixture of 100 g of this polyamine derivative and 20 g of sodium pentasulfide was added to 1000 ml of the same four metal ion-containing aqueous solutions 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. Example 11 In the same device as in Example 1, N′, N″, NN´´´´−
Tetrakis(dithiocarboxy)triethylenetetramine 159.0g, epoxyalkane (12 carbons)
After charging 73.6 g and 500 g of water-acetone (1:1) and carrying out the reaction in the same manner as in Example 10, purification and drying were carried out in the same manner to obtain a brown polyamine derivative powder with a sulfur content of 32.8 wt%. Obtained 230g. A mixture of 100g of this polyamine derivative, 10g of sodium monosulfide, and 5g of sodium pentasulfide.
0.3 g was added to 1000 ml 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. The results are shown in Table 1. Example 12 Commercially available polyethylene polyimine (manufactured by Nippon Shokubai Chemical Co., Ltd., Epomin SP003, molecular weight approximately 300) 99
g in 146 g of ethyl alcohol, heated to 75°C with stirring, and refluxed to dissolve the epoxy alkane (carbon number
12) 212 g was added dropwise, and after the addition was completed, the reaction was continued for an additional 2 hours at the same temperature. After the reaction was completed, the reaction solution was concentrated to obtain 210 g of a yellow crystalline solid. 200 g of the obtained crystalline solid was finely ground and dispersed in 200 g of water, and 20 g of sodium hydroxide was added to give 40 g.
Drop 32g of carbon disulfide at
The reaction was carried out at ℃ for 2 hours. After the reaction was completed, insoluble components were filtered off, washed with water, further washed with acetone, and dried under reduced pressure to obtain 235 g of a yellow pulverized polyamine derivative having a sulfur content of 10.6 wt%. 0.5 g of a mixture of 100 g of this polyamine derivative and 10 g of sodium hydrogen sulfide was added to 1000 ml of the same four metal ion-containing aqueous solutions as in Example 1. And the residual metal ion concentration in the filtrate was measured. The results are shown in Table 1. Comparative Example 1 0.3 g of the same polyamine derivative as in Example 1 was individually added to 1000 ml of the same four metal ion-containing aqueous solutions as in Example 1, and the floc precipitation time, floc production amount, The residual metal ion concentration in the filtrate was measured. The results are shown in Table 1.

〔Effect of the invention〕

As explained above, the metal collection method of the present invention
A polyamine derivative having at least one β-hydroxyalkyl group and at least one dithiocarboxy group or a salt thereof as an N-substituent in one molecule, and at least one of sodium monosulfide, sodium polysulfide, and sodium hydrogen sulfide. Since we adopted a method to collect and remove metal ions in wastewater by adding seeds as a metal scavenger to wastewater containing metal ions, we can use less metal scavenger than conventional metal capture methods. Even the amount added is sufficient to efficiently collect and remove metal ions from wastewater. Moreover, the polyamine derivative used in the present invention can sufficiently collect and remove metal ions even when used alone, but when used in combination with at least one of sodium monosulfide, sodium polysulfide, and sodium hydrogen sulfide, the two can synergize. It works effectively, and the floc sedimentation rate is faster than when a polyamine derivative is used alone, and it has the effect of highly efficiently collecting and removing metal ions in wastewater.

Claims (1)

[Claims] 1. A polyamine derivative having at least one β-hydroxyalkyl group and at least one dithiocarboxy group or a salt thereof as an N-substituent in one molecule, and at least one of sodium monosulfide, sodium polysulfide, and sodium hydrogen sulfide. 1
1. A method for collecting metals, which comprises adding seeds to wastewater containing metal ions to collect and remove metal ions in the wastewater.