JP2008018311A - Treating agent for heavy metal-containing waste water and method for waste water treatment using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heavy metal-containing waste water-treating agent which easily enables solid-liquid separation by efficiently removing a heavy metal contained in waste water and also forms a floc in waste water containing the heavy metal and hardly decomposable waste water containing a chelating agent, and to provide a method for waste water treatment using the agent. <P>SOLUTION: The heavy metal-containing waste water-treating agent comprises at least one sulfur compound selected from the group consisting of mercaptocarboxylic acid, dithionous acid, salts thereof, mercaptocarboxylic ester and dithionous ester, and at least one cationic polymer selected from the group consisting of dicyandiamide condensate, polyallylamine, polyvinylamine and acid salts thereof. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a heavy metal-containing wastewater treatment agent and a wastewater treatment method using the same. More specifically, the present invention relates to a heavy metal-containing wastewater treatment agent useful for wastewater treatment containing wastewater containing heavy metal ions such as printed wiring board cleaning water and plating wastewater, and a wastewater treatment method using the same.

  Conventionally, as a method for removing heavy metals from wastewater containing heavy metal ions, there is a method in which an alkaline substance such as calcium hydroxide is added to the wastewater, precipitated as a hydroxide, and removed through steps such as filtration and decantation. Has been tried. However, this method has a problem that the amount of alkali used is large and the amount of sludge generated is increased.

  Furthermore, in the presence of a chelating agent such as EDTA (ethylenediaminetetraacetic acid), even if the pH is made alkaline, the heavy metal ions that have formed metal complexes with the chelating agent are incompletely precipitated as hydroxides and are completely removed from the wastewater. It was difficult to remove.

  Therefore, as a technology for treating wastewater containing heavy metal ions in the presence of a chelating agent, there is a method of insolubilizing heavy metal ions by adding thiocarbamates that form a strong metal complex with heavy metal ions. If thiocarbamate is used in a pH of acidic to weakly alkaline, there is a problem of generating toxic carbon disulfide gas.To prevent this, waste water should be added with strong alkalinity such as sodium hydroxide. For example, the amount of carbon disulfide gas generated is reduced, but there is a problem that the amount of alkali used increases and the cost increases.

  Japanese Patent No. 3621963 (Patent Document 1) discloses a method for insolubilizing and removing heavy metal ions using a removal agent comprising an anionic polymer containing a carboxyl group and an acidic substance such as iron chloride or mineral acid. Has been. Furthermore, Japanese Patent No. 3696943 (Patent Document 2) discloses a method of insolubilizing and removing heavy metal ions using a treatment agent composed of a novolak resin-containing alkaline substance and an acidic substance such as iron sulfate.

However, in these methods, the heavy metal-containing wastewater containing a chelating agent has a weak ability to insolubilize heavy metals, the formation of flocs is insufficient, and the heavy metals cannot always be sufficiently removed.
Japanese Patent No. 3621963 Japanese Patent No. 3696943

  The present invention facilitates solid-liquid separation by efficiently removing heavy metals contained in wastewater and forming floc in wastewater containing heavy metals and difficult-to-treat wastewater containing chelating agents. The present invention has been made for the purpose of providing a heavy metal-containing wastewater treatment agent that can be used and a wastewater treatment method using the same.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have used a specific sulfur compound and a specific cationic polymer in combination to contain a heavy metal-containing wastewater treatment agent in wastewater. The present inventors have found that it is possible to efficiently remove heavy metals and form flocs and easily perform solid-liquid separation. Based on this finding, the present invention has been completed.

That is, the present invention
(1) at least one sulfur compound selected from the group consisting of mercaptocarboxylic acid, dithionite, salts thereof, mercaptocarboxylate and dithionite, dicyandiamide condensate, polyallylamine, polyvinylamine and the like A metal-containing wastewater treatment agent comprising at least one cationic polymer selected from the group consisting of acid salts of
(2) At least one sulfur compound selected from the group consisting of mercaptocarboxylic acid, dithionite, their salts, mercaptocarboxylate and dithionite, a dicyandiamide condensate, and polyallylamine A wastewater treatment method characterized by adding heavy metals by precipitation by adding at least one cationic polymer selected from the group consisting of polyvinylamine and acid salts thereof,
(3) The wastewater treatment method according to (2), wherein the polymer flocculant is further added to the heavy metal-containing wastewater to precipitate and remove the heavy metal.
Is to provide.

  According to the heavy metal-containing wastewater treatment agent and the wastewater treatment method using the same of the present invention, in general polymer flocculants and inorganic flocculants, including wastewater containing heavy metals such as printed wiring board cleaning water and plating wastewater. With respect to heavy metal-containing wastewater containing a key rate agent that is difficult to remove by coagulation sedimentation, it is possible to effectively and easily perform coagulation sediment removal treatment of heavy metals. In other words, according to the heavy metal-containing wastewater treatment agent of the present invention and the wastewater treatment method using the same, it is possible to easily remove solid metals contained in the wastewater and easily form a solid-liquid separation by forming a floc. can do.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

  The heavy metal-containing wastewater treatment agent of the present invention comprises at least one sulfur compound selected from the group consisting of mercaptocarboxylic acid, dithionite, salts thereof, mercaptocarboxylate and dithionite, dicyandiamide condensate, And at least one cationic polymer selected from the group consisting of polyallylamine, polyvinylamine and their acid salts. When the heavy metal-containing wastewater treatment agent is added to the heavy metal-containing wastewater, the solid-liquid separation can be facilitated by efficiently removing heavy metals contained in the wastewater and forming flocs.

  Examples of the mercaptocarboxylic acid used in the present invention include mercaptoacetic acid, mercaptopropionic acid, mercaptobutyric acid, bis (mercaptomethyl) acetic acid and other mercaptoaliphatic monocarboxylic acids having 2 to 4 carbon atoms, mercaptosuccinic acid, and dimercapto. Examples of the mercaptoaliphatic dicarboxylic acid having 3 to 4 carbon atoms such as succinic acid, mercaptomaleic acid, dimercaptomaleic acid, mercaptomalonic acid and the like include mercaptocarboxylic acid esters such as methyl mercaptoacetate, ethyl mercaptoacetate, mercaptopropionic acid. Examples include mercapto aliphatic monocarboxylic acid esters such as methyl and ethyl mercaptopropionate.

  Examples of salts that form salts with mercaptocarboxylic acid and dithionite include, for example, alkali metal salts such as lithium, potassium, and sodium, ammonia, methylamine, ethylamine, propylamine, dimethylamine, diethylamine, triethylamine, monoethanolamine, Examples thereof include amine salts such as diethanolamine and triethanolamine. Among these, mercaptoaliphatic monocarboxylic acid, mercaptoaliphatic dicarboxylic acid, dithionite and salts thereof are preferably used because the removal property of heavy metal ions is further improved.

  In the cationic polymer comprising dicyandiamide condensate, polyallylamine, polyvinylamine or their acid salts used in the present invention, examples of dicyandiamide condensates include dicyandiamide, ammonium chloride and formaldehyde condensates, dicyandiamide, ammonium chloride and poly Examples include condensates of alkylene polyamines, condensates of dicyandiamide, ammonium chloride, polyalkylene polyamines, and formaldehyde. Examples of the polyalkylene polyamid used in the condensate of dicyandiamide, ammonium chloride, and polyalkylene polyamine, and the condensate of dicyandiamide, ammonium chloride, polyalkylene polyamine, and formaldehyde include, for example, ethylenediamine, diethylenetriamine, triethylenetetraamine, tetraethylenepentamine, and propylene. Examples thereof include diamine and dipropylene triamine. Examples of the acid that forms an acid salt with the dicyandiamide condensate include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and organic acids such as formic acid, acetic acid, lactic acid, malic acid, and citric acid.

  There is no particular limitation on the method for producing dicyandiamide, ammonium chloride and formaldehyde condensate, dicyandiamide, ammonium chloride and polyalkylene polyamine condensate, dicyandiamide, ammonium chloride, polyalkylene polyamine and formaldehyde condensate, and their acid salts. For example, in the case of a condensate of dicyandiamide, ammonium chloride and formaldehyde, dicyandiamide, ammonium chloride and formaldehyde can be reacted at 40 to 100 ° C. using a solvent as necessary. In the case of a condensate of dicyandiamide, ammonium chloride, and polyalkylene polyamine, ammonium chloride and polyalkylene polyamine are reacted at 100 to 150 ° C. using a solvent as necessary, and then reacted with dicyandiamide at 150 to 300 ° C. Can be made. In the case of a condensate of dicyandiamide, ammonium chloride, polyalkylene polyamine and formaldehyde, ammonium chloride and polyalkylene polyamine are reacted at 50 to 100 ° C. using a solvent as necessary, and then dicyandiamide and 50 to 150 ° C. And further reacted with formaldehyde at 40 to 100 ° C. Examples of the solvent used include water, methanol, ethanol, isopropanol, ethylene glycol, diethylene glycol, propylene glycol, ethylene glycol monomethyl ether, ethylene glycol monobutyl ether, acetone, methyl ethyl ketone, dioxane, tetrahydrofuran, and dimethylformamide. . In the case of acid salt, the acid salt can be formed by adding an acid or adding a dicyandiamide condensate to an acid solution, if necessary.

  Examples of allylamines used in the production of polyallylamine and its acid salts include monoallylamines such as allylamine and N-methylallylamine, and diallylamines such as diallylamine and N-methyldiallylamine. Examples of the acid used for forming the polyallylamine acid salt include the same acids as those forming the acid salt of the dicyandiamide condensate.

  There is no particular limitation on the method for producing polyallylamine and its acid salt. For example, allylamine acidified with an acid alone or a mixture of two or more, or sulfur dioxide in the presence of an initiator is required. Accordingly, a polymerization reaction can be performed using a solvent. Examples of the initiator include benzoyl peroxide, lauroyl peroxide, diisopropyl purge carbonate, tert-butyl perbenzoate, di-tert-butyl peroxide, dicumyl peroxide, tert-butyl cumyl peroxide, cumene hydroxyperoxide. Peroxides such as oxide, tert-butyl hydroperoxide, persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate, 2,2′-azobisisobutyronitrile, 2,2′-azobis (2 , 4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2-amidinopropane) dihydrochloride, 2,2′-azobis (2-imidazoline- Azo compounds such as 2-yl-propane) dihydrochloride It can gel. Examples of the solvent used include water, methanol, ethanol, isopropanol, acetone, methyl ethyl ketone, dioxane, tetrahydrofuran, and dimethylformamide. The polymerization reaction temperature is preferably 40 to 120 ° C. Further, polyallylamine can be produced by subjecting an acid salt of polyallylamine to a base treatment such as sodium hydroxide or potassium hydroxide, or a strong basic ion exchange resin treatment. Among these, polymonoallylamine or an acid salt thereof can be preferably used because it forms a floc that is easily separated into solid and liquid and is particularly good.

  Examples of the acid used for forming polyvinylamine and its acid salt include the same acids as those for forming the acid salt of the dicyandiamide condensate.

  There is no particular limitation on the method for producing polyvinylamine or its acid salt. For example, N-vinylformamide is subjected to a polymerization reaction in the presence of an initiator using a solvent as necessary. Part or all can be hydrolyzed. As a polymerization reaction method, it can be produced by the same production method as that for the polyallylamine or its acid salt.

  Examples of the acid used for the hydrolysis include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid, and organic acids such as formic acid and acetic acid. Examples of the base used for hydrolysis include potassium hydroxide and sodium hydroxide. During the hydrolysis, for the purpose of preventing gelation caused by impurities, for example, an antigelling agent such as hydroxyamine hydrochloride or hydroxyamine sulfate may be added for hydrolysis. In general, it is particularly preferable to carry out the hydrolysis after the treatment with this anti-gelling agent. The hydrolysis reaction temperature is preferably 40 to 120 ° C.

Next, the processing method of the heavy metal containing wastewater of this invention is demonstrated. The wastewater treatment method of the present invention comprises at least one sulfur compound selected from the group consisting of mercaptocarboxylic acids, dithionites, their salts, mercaptocarboxylate esters, and dithionite esters to wastewater containing heavy metals. , Dicyandiamide condensate, polyallylamine, polyvinylamine, and at least one cationic polymer selected from the group consisting of acid salts thereof to precipitate and remove heavy metals.
According to this method, a precipitate containing a heavy metal can be obtained efficiently, and the flocs of the precipitate can be prevented from being refined. For this reason, the formed floc can be removed by solid-liquid separation processing such as coagulation sedimentation processing. At this time, since the miniaturization of the floc is prevented, the floc can be easily removed. That is, heavy metals can be removed easily and efficiently.

  In the treatment method of the present invention, the target heavy metal-containing wastewater is wastewater containing heavy metal ions such as cadmium, nickel, mercury, copper, lead, zinc, arsenic, chromium, and particularly contains a chelating agent. Mention may be made of wastewater containing heavy metal ions.

  In the treatment method of the present invention, the sulfur compound is added to the heavy metal-containing wastewater, and then the cationic polymer is added to agglomerate and precipitate the heavy metal. Alternatively, the cationic polymer is added to the heavy metal-containing wastewater, and then the sulfur compound is added to coagulate and precipitate the heavy metal. Alternatively, it is possible to coagulate and precipitate heavy metals by mixing the sulfur compound and the cationic polymer in arbitrary ratios or adding them to the heavy metal-containing wastewater at the same time.

  In the treatment method of the present invention, flocs containing heavy metals that have been agglomerated and precipitated are removed by solid-liquid separation of waste water containing heavy metals, and thus purified waste water is obtained. In addition, the floc containing the heavy metal which agglomerated and precipitated can be dehydrated after solid-liquid separation, and finally disposed or reused as waste. Examples of the solid-liquid separation method include filtration, gravity sedimentation, centrifugal concentration, and membrane separation. Examples of the dehydration method include dehydration using a centrifugal dehydrator, a belt press dehydrator, a screw press dehydrator, a filter press dehydrator, and the like.

  In the treatment method of the present invention, the pH of the wastewater can be adjusted using an acid such as hydrochloric acid, sulfuric acid or nitric acid, or a base such as sodium hydroxide, potassium hydroxide, sodium carbonate or potassium carbonate, if necessary. .

  In the method of the present invention, the amount of sulfur compound added to the wastewater cannot be defined unconditionally because it varies depending on the heavy metal concentration, type, and content of the chelating agent in the wastewater, but it is 10 to 30,000 ppm (mass ratio). Is preferable, and it is more preferable that it is 20-10,000 ppm (mass ratio). When the amount of the sulfur compound added to the wastewater is within the above range, an advantage that the heavy metal in the heavy metal-containing wastewater can be effectively removed is obtained. The amount of the cationic polymer added to the wastewater varies depending on the heavy metal concentration, type, and content of the chelating agent in the wastewater, and thus cannot be specified unconditionally, but is preferably 10 to 30,000 ppm (mass ratio). More preferably, it is -10,000 ppm (mass ratio). When the amount of the cationic polymer added to the wastewater is within the above range, there is an advantage that the heavy metals in the heavy metal-containing wastewater can be effectively aggregated. In the present invention, the mass ratio of the addition amount of the sulfur compound and the cationic polymer (sulfur compound addition amount: cationic polymer addition amount) is preferably 95: 5 to 10:90, and 90:10 to 30 : 70 is more preferable. By setting the mass ratio of the addition amount of the sulfur compound and the cationic polymer within the above range, heavy metals in the heavy metal-containing wastewater can be effectively coagulated and precipitated.

  In the treatment method of the present invention, it is preferable to further add a polymer flocculant to the heavy metal-containing wastewater. Examples of such polymer flocculants include anionic polymer flocculants, cationic polymer flocculants, nonionic polymer flocculants, amphoteric polymer flocculants, and mixtures of these polymer flocculants. Can do. Examples of the anionic polymer flocculant include sodium polyacrylate, partial hydrolyzate of polyacrylamide, copolymer of acrylamide and sodium acrylate, copolymer of acrylamide and sodium vinyl sulfonate, acrylamide and 2-acrylamide. Examples thereof include a copolymer of sodium 2-methylpropanesulfonate and a terpolymer of acrylamide, sodium acrylate, and sodium 2-acrylamido-2-methylpropanesulfonate. Examples of the cationic polymer flocculant include, for example, a quaternized product of dimethylaminoethyl (meth) acrylate or a polymer thereof, a quaternized product of dimethylaminoethyl (meth) acrylate or a copolymer thereof with acrylamide. And Mannich modified product of polyacrylamide or a quaternized product thereof. Examples of nonionic polymer flocculants include polyacrylamide and polyethylene oxide. Examples of the amphoteric polymer flocculant include a quaternized product of dimethylaminoethyl (meth) acrylate or a salt thereof and a copolymer of acrylic acid or a salt thereof and acrylamide. The polymer flocculant used in the present invention usually has a molecular weight of one million to several tens of millions. It is preferable to further add such a polymer flocculant because it can prevent the flocs that have been agglomerated and precipitated from becoming finer and facilitate separation of the floc and the liquid.

  In the method of the present invention, the amount of the polymer flocculant added to the wastewater varies depending on the heavy metal concentration, type, and content of the chelating agent in the wastewater, and thus cannot be specified unconditionally, but is 50 ppm (mass ratio) or less. Is more preferable, and 20 ppm (mass ratio) or less is more preferable. When the amount of the polymer flocculant added to the waste water is within the above range, an advantage that flocs can be effectively formed is obtained.

  In the treatment method of the present invention, an inorganic flocculant may be used in combination so as not to impair heavy metal removal. Examples of such inorganic flocculants include aluminum compounds such as aluminum sulfate, aluminum chloride, polyaluminum chloride, iron chloride (II), iron chloride (III), iron sulfate (II), iron sulfate (III), poly Examples thereof include iron compounds such as iron (III) sulfate, calcium compounds such as lime, and magnesium compounds. Among these, aluminum sulfate, polyaluminum chloride, iron (III) chloride, and polyiron sulfate (III) tend to have good cohesive strength and strong floc formation.

  The heavy metal-containing wastewater treatment agent and the wastewater treatment method using the same of the present invention can be applied to wastewater containing heavy metals and wastewater containing heavy metals further containing a chelating agent. In particular, by applying the heavy metal-containing wastewater treatment agent of the present invention and the wastewater treatment method using the same to wastewater containing a heavy metal further containing a chelating agent, the heavy metal contained in the wastewater can be surely contained. It is possible to remove and form a floc for easy solid-liquid separation.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further in detail, this invention is not limited at all by these Examples.

In the examples, the following four polymer flocculants and four inorganic flocculants were used.
Polymer flocculant C1: Anionic polymer flocculant, Toagosei Co., Ltd., Aron Flock (registered trademark) A101, molecular weight 13 million, polyacrylamide polymer flocculant C2: Cationic polymer flocculant, Hymo ), Hymolock (registered trademark) MP-384, molecular weight 5 million, polydimethylaminoethyl acrylate polymer flocculant C3: Nonionic polymer flocculant, Toagosei Co., Ltd., Aron Flock N107, molecular weight 16 million, polyacrylamide System polymer flocculant C4: amphoteric polymer flocculant, Hymo Co., Ltd., Hymo Lock MS-884, molecular weight 7.5 million, polydimethylaminoethyl acrylate / acrylamide / acrylate system inorganic flocculant D1: aluminum sulfate inorganic flocculant D2: poly Aluminum chloride Inorganic flocculant D3: Iron (III) chloride
Inorganic flocculant D4: Poly iron sulfate (III)

Example 1
A reaction vessel was charged with 53.5 g (1.0 mol) of ammonium chloride, 162.2 g (2.0 mol) of 37% by weight formaldehyde and 300 g of water, and mixed at 40 ° C. for 0.5 hour. Next, 84.0 g (1.0 mol) of dicyandiamide was gradually added at 40 ° C. and further reacted at 95 ° C. for 2 hours. After completion of the reaction, the mixture was cooled and water was added so as to have a concentration of 20% by mass to obtain an aqueous solution of the cationic polymer B1.

  The wastewater treatment method was evaluated using wastewater having a pH of 3.0 containing 50 ppm of copper ions and 100 ppm of EDTA (ethylenediaminetetraacetic acid) as test wastewater.

  Take 200 ml of test wastewater in a 300 ml beaker, add 0.25 g of a 40% by weight aqueous solution of mercaptoacetic acid monoethanolamine while stirring with a jar tester at 120 rpm, and then stir for 3 minutes. 0.5 g of a 20% by mass aqueous solution of polymer B1 was added and stirred for 3 minutes. Further, 0.8 g of a 0.1% by mass aqueous solution of an anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight: 13 million, polyacrylamide type] was added and stirred for 3 minutes.

  Immediately, the floc diameter of the treated wastewater obtained was visually measured using a ruler. The average floc diameter was 6 mm. The treated wastewater is treated with qualitative filter paper No. 2 [Advantech Co., Ltd.] was used for filtration, and the filtrate was measured for heavy metal ion concentration using an ICP emission spectrometer [ICPS-1000II, Shimadzu Corporation]. The copper ion concentration was less than 0.1 ppm.

Example 2
Diethylenetriamine 51.5 (0.5 mol) was charged into the reaction vessel, and ammonium chloride 32.1 g (0.6 mol) was gradually added at 100 ° C., and further reacted at 140 ° C. for 1 hour. Next, 54.6 g (0.65 mol) of dicyandiamide was gradually added at 180 ° C. and further reacted at 260 ° C. for 2 hours. After completion of the reaction, the mixture was cooled and water was added so that the concentration became 20% by mass to obtain an aqueous solution of the cationic polymer B2.

  The same operation as in Example 1 was performed except that this cationic polymer B2 was used instead of the cationic polymer B1 used in Example 1. The average floc diameter was 6 mm and the copper ion concentration was less than 0.1 ppm.

Example 3
Instead of 0.5 g of the 20% by weight aqueous solution of the cationic polymer B1 used in Example 1, 0.25 g of a 40% by weight aqueous solution of polymonoallylamine hydrochloride (molecular weight 5,000) was used as the cationic polymer B3. The same operation as in Example 1 was performed except that. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 4
Instead of 0.5 g of the 20% by mass aqueous solution of the cationic polymer B1 used in Example 1, 0.5 g of a 20% by mass aqueous solution of polymonoallylamine hydrochloride (molecular weight 60,000) was used as the cationic polymer B4. Except that, wastewater treatment was performed in the same manner as in Example 1, and the floc diameter and the copper ion concentration were measured. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 5
Instead of 0.5 g of the 20 wt% aqueous solution of the cationic polymer B1 used in Example 1, 0.25 g of a 40 wt% aqueous solution of polymonoallylamine hydrochloride (molecular weight 150,000) was used as the cationic polymer B5. The same operation as in Example 1 was performed except that. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 6
Instead of 0.5 g of the 20% by weight aqueous solution of the cationic polymer B1 used in Example 1, 0.67 g of a 15% by weight aqueous solution of polymonoallylamine (molecular weight 15,000) was used as the cationic polymer B6. The same operation as in Example 1 was performed. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 7
Instead of using 0.5 g of the 20 wt% aqueous solution of the cationic polymer B1 used in Example 1, 1.0 g of a 10 wt% aqueous solution of polymonoallylamine (molecular weight 60,000) was used as the cationic polymer B7. The same operation as in Example 1 was performed. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 8
Instead of 0.5 g of a 20% by weight aqueous solution of the cationic polymer B1 used in Example 1, 23% by weight of polyvinylamine hydrochloride (molecular weight 140,000, vinylamine structural unit 70 mol%) as the cationic polymer B8. The same operation as in Example 1 was performed except that 0.43 g of an aqueous solution was used. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 9
Instead of 0.5 g of the 20% by weight aqueous solution of the cationic polymer B1 used in Example 1, 17% by weight of polyvinylamine hydrochloride (molecular weight 60,000, vinylamine structural unit 95 mol%) as the cationic polymer B9. The same operation as in Example 1 was performed except that 0.59 g of an aqueous solution was used. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 10
Cationic polymer flocculant C2 [cationic polymer flocculant] instead of anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight 13 million, polyacrylamide type] used in Example 1 , Hymo Co., Ltd., Hymo Lock MP-384, molecular weight 5 million, polydimethylaminoethyl acrylate system] was used, and the same operation as in Example 1 was performed. The average floc diameter was 6 mm and the copper ion concentration was less than 0.1 ppm.

Example 11
Instead of the anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight 13 million, polyacrylamide type] used in Example 1, nonionic polymer flocculant C3 [nonionic polymer flocculant] Toagosei Co., Ltd., Aron Flock N107, molecular weight 16 million, polyacrylamide system] was used, and the same operation as in Example 1 was performed. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 12
Instead of the anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight 13 million, polyacrylamide type] used in Example 1, amphoteric polymer flocculant C4 [Himo Co., Ltd., Hymolock MS −884, molecular weight 7.5 million, polydimethylaminoethyl acrylate / acrylamide / acrylate system], and the same operation as in Example 1 was performed. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 13
The same operation as in Example 1 was performed except that 0.25 g of a 40% by mass aqueous solution of ammonium mercaptoacetate was used instead of 0.25 g of the 40% by mass aqueous solution of monoethanolamine mercaptoacetate used in Example 1. The average floc diameter was 5 mm and the copper ion concentration was less than 0.1 ppm.

Example 14
The same operation as in Example 1 was performed except that 0.25 g of a 40% by mass aqueous solution of sodium mercaptoacetate was used instead of 0.25 g of the 40% by mass aqueous solution of mercaptoacetic acid monoethanolamine used in Example 1. The average floc diameter was 6 mm and the copper ion concentration was less than 0.1 ppm.

Example 15
The same operation as in Example 1 was performed except that 0.25 g of a 40% by mass aqueous solution of potassium mercaptoacetate was used instead of 0.25 g of the 40% by mass aqueous solution of monoethanolamine mercaptoacetate used in Example 1. The average floc diameter was 6 mm and the copper ion concentration was less than 0.1 ppm.

Example 16
The same operation as in Example 1 was performed except that 0.1 g of mercaptoacetic acid was used instead of 0.25 g of the 40 mass% aqueous solution of mercaptoacetic acid monoethanolamine used in Example 1. The average floc diameter was 6 mm and the copper ion concentration was less than 0.1 ppm.

Example 17
The same operation as in Example 1 was performed, except that 0.25 g of a 40% by weight aqueous solution of mercaptopropionic acid monoethanolamine was used instead of 0.25 g of the 40% by weight aqueous solution of mercaptoacetic acid monoethanolamine used in Example 1. It was. The average floc diameter was 6 mm and the copper ion concentration was less than 0.1 ppm.

Example 18
The same as Example 1 except that 0.25 g of 40% by mass aqueous solution of bis (mercaptomethyl) acetic acid monoethanolamine was used instead of 0.25 g of 40% by mass aqueous solution of mercaptoacetic acid monoethanolamine used in Example 1. The operation was performed. The average floc diameter was 5 mm and the copper ion concentration was less than 0.1 ppm.

Example 19
The same operation as in Example 1 was conducted except that 0.25 g of a 40% by mass aqueous solution of monoethanolamine mercaptoacetate used in Example 1 was used instead of 0.25 g of the 40% by mass aqueous solution of monoethanolamine mercaptoacetate used in Example 1. went. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 20
0.25 g of a 40 wt% aqueous solution of monoethanolamine mercaptoacetate used in Example 1, 0.5 g of a 20 wt% aqueous solution of the cationic polymer B1, and a 0.1 wt% aqueous solution of an anionic polymer flocculant C1 0 Instead of 0.8 g, 0.16 g of sodium dithionite, 0.8 g of a 20% by weight aqueous solution of the cationic polymer B1, and 1.2 g of a 0.1% by weight aqueous solution of the anionic polymer flocculant C1 are used, respectively. The same operation as in Example 1 was performed except that. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 21
200 ml of the test waste water used in Example 1 was placed in a 300 ml beaker, and 0.5 g of a 20% by weight aqueous solution of the cationic polymer B1 obtained in Example 1 was added while stirring at 120 rpm with a jar tester. The mixture was stirred for 3 minutes, and then 0.25 g of a 40% by mass aqueous solution of mercaptoacetic acid monoethanolamine was added and stirred for 3 minutes. Further, 0.8 g of 0.1% by weight aqueous solution of anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight 13 million, polyacrylamide type] was added and stirred for 3 minutes for wastewater treatment. The floc diameter and heavy metal ion concentration were measured in the same manner as in Example 1. The average floc diameter was 6 mm and the copper ion concentration was less than 0.1 ppm.

Example 22
200 ml of the test wastewater used in Example 1 was placed in a 300 ml beaker and stirred with a jar tester at a rotation speed of 120 rpm, 0.5 g of a 20% by weight aqueous solution of the cationic polymer B1 obtained in Example 1, and a mercapto. A mixed solution of 0.25 g of a 40% by mass aqueous solution of monoethanolamine acetate was added and stirred for 3 minutes. Next, 0.8 g of 0.1% by weight aqueous solution of anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight 13 million, polyacrylamide type] was added and stirred for 3 minutes to treat wastewater. The floc diameter and heavy metal ion concentration were measured in the same manner as in Example 1. The average floc diameter was 6 mm and the copper ion concentration was less than 0.1 ppm.

Example 23
Instead of the test wastewater of pH 3.0 containing 50 ppm of copper ions and 100 ppm of EDTA (ethylenediaminetetraacetic acid) used in Example 1, the test wastewater of pH 6.0 containing 50 ppm of copper ions and 100 ppm of EDTA (ethylenediaminetetraacetic acid) is used. The same operation as in Example 1 was performed except that was used. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 24
Instead of the test wastewater of pH 3.0 containing 50 ppm of copper ions and 100 ppm of EDTA (ethylenediaminetetraacetic acid) used in Example 1, the test wastewater of pH 9.0 containing 50 ppm of copper ions and 100 ppm of EDTA (ethylenediaminetetraacetic acid) is used. The same operation as in Example 1 was performed except that was used. The average floc diameter was 3 mm and the copper ion concentration was 0.2 ppm.

Example 25
200 ml of the test wastewater used in Example 1 was placed in a 300 ml beaker, and 0.5 g of a 40% by mass aqueous solution of mercaptoacetic acid monoethanolamine was added with stirring with a jar tester at 120 rpm, followed by stirring for 3 minutes. Then, 0.8 g of a 20% by weight aqueous solution of the cationic polymer B1 obtained in Example 1 was added, and the mixture was stirred for 3 minutes for wastewater treatment. The floc diameter and heavy metal ion concentration were determined in the same manner as in Example 1. It was measured. The average floc diameter was 2 mm and the copper ion concentration was less than 0.1 ppm.

Example 26
Instead of 0.5 g of a 40 wt% aqueous solution of mercaptoacetic acid monoethanolamine and 0.8 g of a 20 wt% aqueous solution of the cationic polymer B1 used in Example 25, 0.4 g of sodium dithionite and a cation, respectively, The same operation as in Example 25 was performed except that 2.0 g of a 20% by mass aqueous solution of the conductive polymer B1 was used. The average floc diameter was 2 mm and the copper ion concentration was less than 0.1 ppm.

Example 27
Into a 300 ml beaker, 200 ml of the test wastewater used in Example 1 was added with 0.25 g of a 40% by weight aqueous solution of mercaptoacetic acid monoethanolamine while stirring with a jar tester at 120 rpm, and then stirred for 3 minutes. Then, 0.5 g of a 20% by mass aqueous solution of the cationic polymer B1 obtained in Example 1 was added and stirred for 3 minutes. Further, the pH was adjusted to 6.0 with a 20% by mass aqueous sodium hydroxide solution, and 1.25 g of an 8% by mass aqueous solution of an inorganic flocculant D1 [aluminum sulfate] was added and stirred for 3 minutes. Next, 0.8 g of a 0.1% by weight aqueous solution of an anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight 13 million, polyacrylamide type] was added and stirred for 3 minutes to treat waste water. The floc diameter and heavy metal ion concentration were measured in the same manner as in Example 1. The average floc diameter was 6 mm and the copper ion concentration was less than 0.1 ppm.

Example 28
Example except that 1.0 g of a 10% by weight aqueous solution of an inorganic flocculant D2 [polyaluminum chloride] was used instead of 1.25 g of the 8% by weight aqueous solution of the inorganic flocculant D1 [aluminum sulfate] used in Example 26. The same operation as 28 was performed. The average floc diameter was 6 mm and the copper ion concentration was less than 0.1 ppm.

Example 29
Instead of using 1.25 g of an 8% by mass aqueous solution of the inorganic flocculant D1 [aluminum sulfate] used in Example 27, 0.91 g of an 11% by mass aqueous solution of the inorganic flocculant D4 [polyiron sulfate (III)] was used. The same operation as in Example 27 was performed. The average floc diameter was 6 mm and the copper ion concentration was less than 0.1 ppm.

Example 30
0.25 g of a 40 wt% aqueous solution of mercaptoacetic acid monoethanolamine used in Example 27, 0.5 g of a 20 wt% aqueous solution of cationic polymer B1, and 1.25 g of an 8 wt% aqueous solution of inorganic flocculant D1 [aluminum sulfate]. And 0.2 g of 0.1% by weight aqueous solution of anionic polymer flocculant C1, 0.2 g of sodium dithionite, 0.8g of 20% by weight aqueous solution of cationic polymer B1, respectively, inorganic flocculant The same operation as in Example 27 was performed, except that 0.53 g of a 38% by mass aqueous solution of D3 [iron (III) chloride] and 1.2 g of a 0.1% by mass aqueous solution of anionic polymer flocculant C1 were used. The average floc diameter was 4 mm and the copper ion concentration was less than 0.1 ppm.

Example 31
The wastewater treatment method was evaluated using wastewater having a pH of 3.0 containing 20 ppm of chromium ions and 100 ppm of EDTA (ethylenediaminetetraacetic acid) as test wastewater.

  Take 200 ml of test wastewater in a 300 ml beaker, add 0.15 g of 40% by mass aqueous solution of mercaptoacetic acid monoethanolamine with stirring with a jar tester at 120 rpm, and stir for 3 minutes. 0.3 g of a 20% by weight aqueous solution of the obtained cationic polymer B1 was added and stirred for 3 minutes. Furthermore, 0.4 g of 0.1% by weight aqueous solution of anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight 13 million, polyacrylamide type] was added and stirred for 3 minutes and then stirred for 3 minutes. Then, the wastewater treatment was performed, and the floc diameter and heavy metal ion concentration were measured in the same manner as in Example 1. The average floc diameter was 6 mm and the chromium ion concentration was less than 0.1 ppm.

Example 32
Test wastewater of pH 3.0 containing 20 ppm of nickel ions and 100 ppm of EDTA (ethylenediaminetetraacetic acid) instead of 20 ppm of chromium ions and 100 ppm of EDTA (ethylenediaminetetraacetic acid) used in Example 31 The same operation as in Example 31 was performed except that was used. The average floc diameter was 6 mm, and the nickel ion concentration was less than 0.1 ppm.

Example 33
The wastewater treatment method was evaluated using wastewater having a pH of 3.0 containing 10 ppm each of copper ions, chromium ions, nickel ions and cadmium ions and 100 ppm of EDTA (ethylenediaminetetraacetic acid) as test wastewater.

  Take 200 ml of test wastewater in a 300 ml beaker, add 0.35 g of 40% by weight aqueous solution of mercaptoacetic acid monoethanolamine while stirring with a jar tester at 120 rpm, and stir for 3 minutes. 0.4 g of a 20% by weight aqueous solution of the obtained cationic polymer B1 was added and stirred for 3 minutes. Furthermore, 0.6 g of 0.1% by weight aqueous solution of anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight 13 million, polyacrylamide type] was added and stirred for 3 minutes for wastewater treatment. The floc diameter and heavy metal ion concentration were measured in the same manner as in Example 1. The average floc diameter was 4 mm, and the concentrations of copper ion, chromium ion, nickel ion and cadmium ion were all less than 0.1 ppm.

Comparative Example 1
Take 200 ml of the test wastewater used in Example 1 in a 300 ml beaker, add calcium hydroxide so that the pH of the wastewater becomes 10.0 while stirring with a jar tester at 120 rpm, and stir for 3 minutes. Next, 0.8 g of 0.1% by weight aqueous solution of anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight 13 million, polyacrylamide type] was added and stirred for 3 minutes to treat wastewater. The floc diameter and heavy metal ion concentration were measured in the same manner as in Example 1. The average floc diameter was 1 mm, and the copper ion concentration was 23.0 ppm.

Comparative Example 2
Into a 300 ml beaker, 200 ml of the test wastewater used in Example 1 was added with 0.25 g of a 40% by weight aqueous solution of mercaptoacetic acid monoethanolamine while stirring with a jar tester at 120 rpm, and then stirred for 3 minutes. In addition, 0.8 g of a 0.1% by weight aqueous solution of an anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight 13 million, polyacrylamide type] was added and stirred for 3 minutes to perform wastewater treatment. The floc diameter and heavy metal ion concentration were measured in the same manner as in Example 1. The average floc diameter was less than 1 mm, and the copper ion concentration was 15.2 ppm.

Comparative Example 3
200 ml of the test wastewater used in Example 1 was placed in a 300 ml beaker, and 0.5 g of a 20% by weight aqueous solution of the cationic polymer B1 obtained in Example 1 was added while stirring with a jar tester at 120 rpm. And stirred for 3 minutes. Further, 0.8 g of 0.1% by weight aqueous solution of anionic polymer flocculant C1 [Toagosei Co., Ltd., Aron Flock A101, molecular weight 13 million, polyacrylamide type] was added and stirred for 3 minutes for wastewater treatment. The floc diameter and heavy metal ion concentration were measured in the same manner as in Example 1. No floc was formed, and the copper ion concentration was 47.6 ppm.

  Examples 24 and 25 in which a sulfur compound was added to a heavy metal-containing wastewater containing a chelating agent and then a cationic polymer was added, as can be seen in Table 1-1, Table 1-2, and Table 1-3. Then, floc aggregates are formed and heavy metals are almost removed. In Examples 1 to 23 in which a polymer flocculant is further added and Examples 26 to 29 in which a polymer flocculant and an inorganic flocculant are further added, floc aggregates are formed, and heavy metals are almost removed. Has been.

On the other hand, in Comparative Example 1 of the conventional method using calcium hydroxide, flocs are formed, but heavy metals are not sufficiently removed. In Comparative Example 2 in which only the sulfur compound and the polymer flocculant were added, the floc diameter became fine, and in Comparative Example 3 in which only the cationic polymer and the polymer flocculant were added, the floc diameter was not formed, and the heavy metal was sufficient. It has not been removed.

Claims (3)

At least one sulfur compound selected from the group consisting of mercaptocarboxylic acid, dithionite, salts thereof, mercaptocarboxylate and dithionite;
At least one cationic polymer selected from the group consisting of dicyandiamide condensate, polyallylamine, polyvinylamine and their acid salts;
A heavy metal-containing wastewater treatment agent, comprising:   Heavy metal-containing wastewater containing at least one sulfur compound selected from the group consisting of mercaptocarboxylic acid, dithionite, their salts, mercaptocarboxylate and dithionite, dicyandiamide condensate, polyallylamine, polyvinylamine And at least one cationic polymer selected from the group consisting of the acid salts thereof, and precipitation removal of heavy metals. The wastewater treatment method according to claim 2, wherein the polymer flocculant is further added to the heavy metal-containing wastewater to precipitate and remove the heavy metal.