JP2019214037A - Water treatment method and water treatment agent - Google Patents

Abstract

To provide a water treatment method capable of reducing water soluble COD components stably even when an amount of a water treatment agent is used excessively with respect to kinds and amounts of water soluble COD components involved in a water to be treated and variation of drainage volume.SOLUTION: The water treatment method includes a step of addition, to a water to be treated, of a water treatment agent (P1) including a copolymer (M) having a weight-average molecular weight of 500-1,000,000, prepared by polymerization of a monomer (m1) bearing a cationic functional group and a monomer (m2) not bearing a cationic functional group, and a water treatment agent (P2) including at least one salt (S) selected from a group consisting of a silicate, a phosphate and a borate.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a water treatment method and a water treatment agent. More specifically, the present invention relates to a water treatment method and a water treatment agent for removing a water-soluble COD component from water containing a water-soluble COD component, such as sludge, various industrial wastewaters, and purified water.

Conventionally, activated carbon treatment, ultraviolet irradiation, ozone treatment, Fenton treatment in which ferrous sulfate and hydrogen peroxide are combined, etc. have been used as methods for removing water-soluble COD components contained in factory wastewater and the like. However, all of them have high processing costs and cannot be said to be widely used.
On the other hand, a method of removing a water-soluble COD component using a so-called polymer flocculant has been proposed (for example, Patent Document 1). However, although the conventional treatment method uses a water-soluble COD component reducing agent such as a polymer flocculant that can widely cope with the difference in the type of the water-soluble COD component in the wastewater, To cope with fluctuations in the type and amount of water-soluble COD and fluctuations in the flow rate of wastewater by adding an excessive amount of the polymer flocculant, if the polymer flocculant is added in excess of the actual optimum addition amount There has been a problem that the polymer flocculant itself becomes a water-soluble COD component, and the amount of the water-soluble COD component increases.

Japanese Patent No. 4923834

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to provide a water treatment agent for changing the type and amount of water-soluble COD components contained in water to be treated and fluctuations in the amount of wastewater. It is an object of the present invention to provide a water treatment method capable of stably reducing the water-soluble COD component even if the amount is excessively used.

  The present inventors have intensively studied to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention relates to a copolymer (M) having a weight average molecular weight of 500 to 1,000,000 obtained by polymerizing a monomer (m1) having a cationic functional group and a monomer (m2) having no cationic functional group. And a water treatment agent (P2) containing at least one salt (S) selected from the group consisting of silicates, phosphates and borates in the water to be treated. A water treatment method including a step of adding; a copolymer having a weight average molecular weight of 500 to 1,000,000 obtained by polymerizing a monomer (m1) having a cationic functional group and a monomer (m2) having no cationic functional group. A water treatment agent (P1) containing the coalesced (M) and a water treatment agent (P2) containing at least one salt (S) selected from the group consisting of silicates, phosphates and borates. It is a water treatment agent (P).

  The water treatment method of the present invention can suppress the increase of the water-soluble COD component even under the condition where the added amount of the water treatment agent is excessive, and can exhibit a stable water-soluble COD reduction effect.

It is a graph which shows the correlation between TOC and COD. It is a graph which shows the relationship between the addition amount of water treatment agent (P1), and COD.

  The water treatment method of the present invention provides a copolymer having a weight average molecular weight of 500 to 1,000,000 obtained by polymerizing a monomer (m1) having a cationic functional group and a monomer (m2) having no cationic functional group. A water treatment agent (P1) containing (M) and a water treatment agent (P2) containing at least one salt (S) selected from the group consisting of silicates, phosphates and borates A water treatment method including a step of adding to water.

The water treatment agent (P1) in the present invention has a weight average molecular weight of 500 to 1,000,000 obtained by polymerizing a monomer (m1) having a cationic functional group and a monomer (m2) having no cationic functional group. Contains a copolymer (M). As the copolymer (M), one type may be used alone, or two or more types may be used in combination.
The cationic group functional group contained in the copolymer (M) is an aminium group in which a proton is added to a primary amino group, a secondary amino group, or a tertiary amino group, from the viewpoint of water-soluble COD reduction performance. It is preferably a quaternary ammonium group.

Preferred as the copolymer (M) from the viewpoint of the water-soluble COD reduction performance are a copolymer containing a (meth) acrylate having a cationic group as a constituent monomer, and an acrylic acid having a cationic group. Copolymer containing amide as a constituent monomer, hydrochloride of epichlorohydrin and dimethylamine polycondensate, copolymer of diallyldimethylammonium chloride and sulfur dioxide, copolymer of diallyldimethylammonium chloride and acrylamide, and diallylamine hydrochloride A copolymer of a salt and sulfur dioxide is exemplified.
In the present invention, (meth) acrylic acid represents methacrylic acid and / or acrylic acid.

  As the copolymer (M), from the viewpoint of water-soluble COD reduction performance, a copolymer containing a (meth) acrylic acid ester having a cationic group as a constituent monomer and an acrylic acid amide having a cationic group are used. A copolymer containing as a constituent monomer is preferable, and a cationic monomer (m11) represented by the following general formula (1) and / or a cationic monomer (m12) represented by the following general formula (2) is a constituent monomer. More preferably, it is a copolymer containing a monomer.

^{_{CH 2 = C (R 1)}} -CO-X-Q-N + (R 2) 3 · Z - (1)

R ¹ in the general formula (1) represents a hydrogen atom or a methyl group.
In the general formula (1), each of three R ² independently represents a hydrogen atom, an alkyl group having 1 to 22 carbon atoms, or a benzyl group.
Examples of the alkyl group having 1 to 22 carbon atoms include methyl, ethyl, n-propyl, isopropyl, butyl, heptyl, octyl, decyl, dodecyl, tetradecyl, hexadecyl, octadecyl, and eicosyl. And docosyl groups.
R ² is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms and a benzyl group, and more preferably a methyl group, from the viewpoint of a water-soluble COD reduction effect.
X in the general formula (1) represents an oxygen atom or NH (imino group).

Q in the general formula (1) represents an alkylene group having 1 to 6 carbon atoms.
Examples of the alkylene group having 1 to 6 carbon atoms include a methylene group, an ethylene group, a propylene group, a butylene group, a pentylene group and a hexylene group, and the propylene group, a butylene group, a pentylene group and a hexylene group may be linear. It may have a branch. When the carbon number of the alkylene group is 6 or less, the solubility of the copolymer (M) in water decreases, and the water treating agent (P1) exhibits an excellent water-soluble COD component-reducing effect.
Q is preferably an alkylene group having 1 to 4 carbon atoms from the viewpoint of water solubility of the copolymer (M).

Z ⁻ represents a conjugate base (anionic group) of a Bronsted acid or an anionic group derived from a quaternizing agent.
Examples of Bronsted acids include inorganic acids (such as hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid) and organic acids (such as sulfonic acid (such as methylsulfonic acid, dodecylbenzenesulfonic acid, and naphthalenesulfonic acid), and carboxylic acid (oxalic acid, acetic acid, and maleic acid). Etc.) and phosphonic acids (such as methylphosphonic acid and phenylphosphonic acid)].
Examples of the quaternizing agent include methyl chloride, dimethyl sulfate and benzyl chloride.
Z ^- Preferred water treatment agent according to (P1) from the viewpoint of reducing the effect of water-soluble COD components as ^the, Cl ^-, HSO ₄ - and CH ₃ SO ₄ ^- a.
As the cationic monomer (m11) represented by the general formula (1), one type may be used alone, or two or more types may be used in combination.

^{_{(CH 2 = C (R 3}} ) -CH 2) 2 -N + (R 4) 2 · Z - (2)

R ³ in the general formula (2) represents a hydrogen atom or a methyl group.
There are two R ⁴ in the general formula (2) each independently represent a hydrogen atom, an alkyl group or a benzyl group having 1 to 22 carbon atoms. As the alkyl group having 1 to 22 carbon atoms for R ^4, the same as those exemplified for R ² in general formula (1) can be mentioned.
R ⁴ is preferably a hydrogen atom, an alkyl group having 1 to 6 carbon atoms and a benzyl group, and more preferably a methyl group, from the viewpoint of a water-soluble COD reduction effect.

Z ⁻ in the general formula (2) represents a conjugate base of a Bronsted acid or an anionic group derived from a quaternizing agent, and examples thereof include the same as those exemplified as Z ^{− in the} general formula (1). The same is true for
As the cationic monomer (m12) represented by the general formula (2), one type may be used alone, or two or more types may be used in combination.

Specific examples of preferable examples of the cationic monomer (m11) represented by the general formula (1) include the amino group-containing (meth) acrylate described below and the Bronsted of the amino group-containing (meth) acrylamide described below. Examples thereof include a salt with an acid and a quaternized product of the quaternizing agent.
In the present invention, (meth) acrylate means methacrylate and / or acrylate, and (meth) acrylamide means methacrylamide and / or acrylamide.

  Preferred amino group-containing (meth) acrylates include amino group-containing (meth) acrylates having 4 to 10 carbon atoms, and more preferred are aminomethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, and dimethylamino. Propyl (meth) acrylate and dimethylaminobutyl (meth) acrylate.

  Preferred amino group-containing (meth) acrylamides include amino group-containing (meth) acrylamides having 4 to 8 carbon atoms. From the viewpoint of hydrophilicity, aminomethyl (meth) acrylamide and dimethylaminoethyl (meth) are more preferable. ) Acrylamide, aminopropyl (meth) acrylamide and aminobutyl (meth) acrylamide.

  Among the cationic monomers (m12) represented by the general formula (2), particularly preferred is diallyldimethylammonium chloride.

  When a salt is used as the monomer (m1) having a cationic functional group, the salt may be polymerized or a salt may be formed after the polymerization.

  Examples of the monomer (m2) having no cationic functional group in the present invention include a nonionic monomer (m21) and an anionic monomer (m22). As (m2), one type may be used alone, or two or more types may be used in combination.

  Examples of the nonionic monomer (m21) include an alkyl (meth) acrylate having 4 to 30 carbon atoms (m211), an unsaturated hydrocarbon having 2 to 30 carbon atoms (m212), and a (meth) acrylamide monomer having 3 to 30 carbon atoms. (M213), vinylamine-based monomer (m214), vinylether-based monomer (m215), (meth) allylamine-based monomer (m216), (meth) allylether-based monomer (m217), and monomer having an unsaturated group and an epoxy group (m218) ) And the like.

  Examples of the alkyl (meth) acrylate having 4 to 30 carbon atoms (m211) include methyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate, ethylene glycol di (meth) acrylate, and pentaerythritol poly (valency: 2-4) (meth) acrylate and dipentaerythritol hexa (meth) acrylate.

  Examples of the unsaturated hydrocarbon having 2 to 30 carbon atoms (m212) include ethylene, nonene, styrene and 1-methylstyrene.

  Examples of the (meth) acrylamide-based monomer (m213) having 3 to 30 carbon atoms include (meth) acrylamide, N-methyl (meth) acrylamide, N-butyl (meth) acrylamide, and N, N'-methylenebis (meth) acrylamide. Is mentioned.

  Examples of the vinylamine-based monomer (m214) include vinylamine, divinylamine, and a polyvalent (divalent to pentavalent or more) amine [having two or more carbon atoms and a number average molecular weight (hereinafter abbreviated as “Mn”) 3,000 or less, Examples thereof include polyvinylamine such as ethylenediamine and polyethyleneimine (having 4 or more carbon atoms and Mn of 3,000 or less)].

  Examples of the vinyl ether monomer (m215) include vinyl ethers, divinyl ethers, polyhydric alcohols having 2 or more carbon atoms and Mn 3,000 or less, for example, alkylene (2 to 6 or more carbon atoms) glycol [ethylene glycol, propylene glycol and 1 , 6-hexanediol, etc.], polyoxyalkylene glycol [for example, polyethylene glycol (chemical formula of 106 or more and Mn 3,000 or less), polypropylene glycol (chemical formula of 134 or more and Mn 3,000 or less), polyoxyethylene / polyoxypropylene block Copolymer (Mn 3,000 or less)], trimethylolethane, trimethylolpropane, (poly) glycerin, pentaerythritol, sorbitol, starch, etc. It is.

  Examples of the (meth) allylamine-based monomer (m216) include (meth) allylamine, di (meth) allylamine, N-alkyl (having 1 to 20 carbon atoms) di (meth) allylamine, and polyvalent (divalent to pentavalent or divalent). And poly (meth) allylamine having amines of 2 or more and Mn of 3,000 or less, for example, ethylenediamine and polyethyleneimine (carbon number of 4 or more and Mn of 3,000 or less).

  Examples of the (meth) allyl ether-based monomer (m217) include di (meth) allyl ether, poly (meth) allyl ether of polyhydric alcohol (as described above) and poly (meth) allyloxyalkane (having 1 to 20 carbon atoms). ) (Tetraallyloxyethane and the like).

  Examples of the monomer (m218) having an unsaturated group and an epoxy group include glycidyl (meth) acrylate, 3,4-epoxyhexahydrobenzyl (meth) acrylate and (meth) acrylate of polyethylene glycol monoglycidyl ether (Mn 6,000 or less) ) And the like.

  Examples of the anionic monomer (m22) include an unsaturated carboxylic acid (anhydride) having 2 to 30 carbon atoms (m221) and an unsaturated sulfonic acid having 2 to 24 carbon atoms (m222).

Examples of the unsaturated carboxylic acid having 2 to 30 carbon atoms (anhydride) (m221) include (meth) acrylic acid, (anhydride) maleic acid, fumaric acid, (anhydride) itaconic acid, vinylbenzoic acid, allylacetic acid and maleic acid. And polyethers with monoesters.
In the present invention, the acid (anhydride) means an acid and / or an acid anhydride.

  Examples of the unsaturated sulfonic acid having 2 to 24 carbon atoms (m222) include an aliphatic unsaturated sulfonic acid having 2 to 20 carbon atoms (vinylsulfonic acid) and an aromatic unsaturated sulfonic acid having 6 to 20 carbon atoms (styrene). Sulfonic acid, etc.), a sulfo group-containing (meth) acrylate having 2 to 24 carbon atoms (a sulfoalkyl (meth) acrylate having an alkyl group having 2 to 20 carbon atoms [2- (meth) acryloyloxyethane-1-propane) Sulfonic acid, 2- (meth) acryloyloxyethane-1-butanesulfonic acid, 3- (meth) acryloyloxypropanesulfonic acid, 4- (meth) acryloyloxybutanesulfonic acid, 2- (meth) acryloyloxy-2, 2-dimethylethanesulfonic acid, p- (meth) acryloyloxymethylbenzenesulfonic acid, etc.), containing a sulfo group (meth ) Acrylamide [2- (meth) acryloylaminoethanesulfonic acid, 2- or 3- (meth) acryloylaminopropanesulfonic acid, 2- or 4- (meth) acryloylaminobutanesulfonic acid, 2- (meth) acryloylamino- 2,2-dimethylethanesulfonic acid, p- (meth) acryloylaminomethylbenzenesulfonic acid, etc.] and alkyl (meth) allyl sulfosuccinate having 1 to 20 carbon atoms in the alkyl group [methyl (meth) allyl sulfosuccinate) Etc.].

  Of the above (m2), (m211), (m212), (m213) and (m221) are preferable from the viewpoint of the water-soluble COD reduction performance of the water treatment agent (P1), and (m211) is more preferable. (M212) and (m221), particularly preferred are alkyl (meth) acrylates having 3 to 30 carbon atoms, unsaturated hydrocarbons having 8 to 10 carbon atoms, (meth) acrylamide and (meth) acrylic acid. Most preferred are alkyl (meth) acrylates having 4 to 20 carbon atoms, styrene and (meth) acrylic acid.

  The molar ratio [(m1) :( m2)] of the monomer (m1) having a cationic functional group to the monomer (m2) having no cationic functional group in the constituent monomers of the copolymer (M) is treated with water. From the viewpoint of the water-soluble COD reduction performance of the agent (P1), preferably 10:90 to 99.9: 0.1, more preferably 12:88 to 95: 5, and particularly preferably 15:85 to 90: 10, most preferably 15:85 to 80:20. Within this range, in addition to the effect of reducing water-soluble COD, the effect of improving the clarity of the filtrate and the effect of decoloring are improved, and the effect of reducing the water content of the dehydrated cake by using the polymer coagulant described below is improved. Become.

  When a difunctional or more crosslinkable monomer is used as the monomer (m2) having no cationic functional group, the amount of the cationic functional group is determined based on the water-soluble COD reduction performance of the water treatment agent (P1). Based on the total weight of the monomer (m1) having no cationic functional group and the monomer (m2) having no cationic functional group, preferably 0.001 to 1% by weight, more preferably 0.01 to 0.5% by weight, and particularly preferably. Is 0.05 to 0.2% by weight.

The method for producing the copolymer (M) is not particularly limited, and radical polymerization methods, for example, solution drop polymerization, reverse phase suspension polymerization, photopolymerization, precipitation polymerization, and reverse phase emulsion polymerization can be employed. Of these, solution drop polymerization is preferred from the viewpoint of temperature control and molecular weight control during polymerization.
As the solution drop polymerization, for example, a method of dropping a solution of a monomer, a solvent and a radical polymerization initiator below the boiling point of the solvent (for example, JP-A-6-212942), and when an organic solvent is used as a solvent, From the viewpoints of handling risk and environmental protection, it is preferable to remove the solvent and to add water as needed to produce.

Examples of the solvent used for the production of the copolymer (M) include water, alcohols (such as methanol, ethanol and isopropyl alcohol), ketones (such as methyl ethyl ketone and acetone), tetrahydrofuran (THF), dimethylformamide (DMF) and the like. Examples include polar solvents such as mixtures and non-polar solvents such as toluene and xylene.
Among these, a mixed solvent of water and an alcohol is preferable from the viewpoint of solubility of a monomer and an initiator and ease of desolvation after polymerization, and more preferable is a mixed solvent of water and isopropyl alcohol. is there.

  Examples of the radical polymerization initiator in the radical polymerization method include water-soluble azo initiators [eg, azobisamidinopropane (salt) [eg, 2,2′-azobis (2-methylpropionamidine) dihydrochloride], azobiscyano Valeric acid (salt) and 2,2′-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] (salt)], an oil-soluble azo initiator (for example, azobiscyanovaleronitrile, azobis Isobutyronitrile and azobiscyclohexanecarbonitrile), water-soluble peroxides (inorganic peroxides (ammonium persulfate, sodium persulfate, hydrogen peroxide, etc.), organic peroxides (peracetic acid, t-butyl hydroperoxide) Oil-soluble peroxides (eg, benzoyl peroxide, cumene hydroxy peroxide, di-t- Chill peroxide and di -t- butyl peroxy hexahydro terephthalate) and the like.

The above peroxide may be used as a redox initiator in combination with a reducing agent. Examples of the reducing agent include bisulfites (eg, sodium bisulfite, potassium bisulfite, and ammonium bisulfite), and reducing metal salts [eg, iron sulfate (II)] tertiary amines [eg dimethylaminobenzoic acid (salt) and dimethylaminoethanol], amine complexes of transition metal salts [eg pentamethylenehexamine complex of cobalt (III) chloride, diethylenetriamine complex of copper (II) chloride And an organic reducing agent (for example, ascorbic acid).
The azo initiator, peroxide initiator and redox initiator may be used alone or in combination of two or more.

  The amount of the radical polymerization initiator used is preferably from 0.001 to 20% by weight, more preferably from 0.005 to 10% by weight, based on the total weight of the monomers, from the viewpoint of obtaining the optimum molecular weight as the copolymer (M). %, Particularly preferably 0.01 to 5% by weight, most preferably 0.05 to 3% by weight.

If necessary, a chain transfer agent for radical polymerization may be used. The chain transfer agent for radical polymerization is not particularly limited, and is, for example, a compound having one or more hydroxyl groups in a molecule [having a chemical formula of 32 or more and Mn of 50,000 or less, such as methanol, ethanol, isopropyl alcohol, and ethylene. Glycol, propylene glycol, polyethylene glycol (chemical formula weight of 106 or more and Mn 50,000 or less) and (poly) ethylene (poly) propylene glycol (chemical formula weight of 120 or more and Mn 50,000 or less)], one or more in the molecule [Eg, ammonia and amines having 1 to 30 carbon atoms (eg, methylamine, dimethylamine, triethylamine and propanolamine)], sodium hypophosphite and one or more thiol groups in the molecule Compounds having It is.
Of these, sodium hypophosphite and a compound having one or more thiol groups in the molecule are preferable from the viewpoint of controlling the molecular weight.

  Compounds having a thiol group in the molecule include the following (1) and (2), salts thereof [alkali metal (eg, lithium, sodium, and potassium) salts, alkaline earth metal (eg, magnesium and calcium) salts, Ammonium salts, amine salts having 1 to 20 carbon atoms and inorganic acids (for example, hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid)], and mixtures thereof.

(1) Monovalent thiol Aliphatic thiol having 1 to 20 carbon atoms (for example, methanethiol, ethanethiol, propanethiol, n-octanethiol, n-dodecanethiol, hexadecanethiol, n-octadecanethiol, 2-mercaptoethanol, mercapto) Acetic acid, 3-mercaptopropionic acid, 1-thioglycerol, thioglycolic acid monoethanolamine, 1-thioglycerol, thioglycolic acid monoethanolamine, thiomaleic acid, cysteine and 2-mercaptoethylamine), an oil having 5 to 20 carbon atoms Examples include cyclic thiols (for example, cyclopentanethiol and cyclohexanethiol) and aromatic (fatty) thiols having 6 to 12 carbon atoms (for example, benzenethiol, benzylmercaptan and thiosalicylic acid).

(2) polyvalent thiol dithiol [aliphatic dithiol having 2 to 40 carbon atoms (for example, ethanedithiol, diethylenedithiol, triethylenedithiol, propanedithiol, 1,3- or 1,4-butanedithiol, 1,6-hexanedithiol) And neopentanedithiol), an alicyclic dithiol having 5 to 20 carbon atoms (for example, cyclopentanedithiol and cyclohexanedithiol) and an aromatic dithiol having 6 to 16 carbon atoms (for example, benzenedithiol and biphenyldithiol).

  When the chain transfer agent for radical polymerization is used, the amount used is preferably 0.001 to 10% by weight based on the total weight of the constituent monomers, from the viewpoint of obtaining the optimum molecular weight as the copolymer (M). , More preferably 0.005 to 5% by weight, particularly preferably 0.01 to 3% by weight, and most preferably 0.05 to 1% by weight.

  The monomer concentration in the monomer solution in the solution drop polymerization is preferably 5 to 90% by weight, more preferably 10 to 80% by weight, particularly preferably 15 to 75% by weight, most preferably 25 to 90% by weight based on the total weight of the monomer solution. ７０70% by weight.

The polymerization temperature in the solution drop polymerization is preferably controlled so as to keep the predetermined temperature constant (for example, the predetermined temperature ± 5 ° C.) from the viewpoint of controlling the molecular weight. The temperature can be controlled by appropriately heating and cooling the reaction tank. However, it is preferable to carry out drop polymerization at a boiling point of the solvent since a predetermined temperature can be easily kept constant. The boiling point of the solvent can be adjusted by the type and pressure of the solvent.
The polymerization temperature is preferably from 40 to 190 ° C, more preferably from 50 to 180 ° C, particularly preferably from 60 to 170 ° C, and most preferably from 80 to 150 ° C, from the viewpoint of easy temperature control and safety.

  The end point of the reaction can be confirmed at the time when the heat generated by the polymerization is eliminated, but the polymerization time is preferably from 1 to 24 hours from the time when the initiation of the polymerization was confirmed by the generation of heat, from the viewpoint of completing the polymerization and reducing the residual monomer. Yes, more preferably for 2 to 12 hours. The above-mentioned monomer concentration, polymerization temperature and polymerization time can be appropriately adjusted depending on the monomer composition, polymerization method, type of initiator and the like.

  When an organic solvent is used as a solvent at the time of polymerization, it is preferable to replace the organic solvent with water after removing the solvent from the viewpoint of mixing of the organic solvent into wastewater and danger of handling when the water treatment agent (P1) is used. preferable. Desolvation may be performed by heating at normal pressure, or may be performed under reduced pressure. As a method of replacing with water, water may be added at any stage before, during or after desolvation.

  The weight average molecular weight (hereinafter abbreviated as “Mw”) of the copolymer (M) is from 500 to 1,000,000 in view of the solubility of the copolymer (M) in water and the water-soluble COD reduction performance. , Preferably from 5,000 to 500,000, more preferably from 10,000 to 250,000, and most preferably from 15,000 to 200,000.

Mw in the present invention is measured by gel permeation chromatography under the following conditions.
Measuring machine: HLC-8220GPC, column manufactured by Tosoh Corporation: TSKgel Guardcolumn PWXL-CP, TSKgel 6000-PWXL-CP, TSKgel 5000-PWXL-CP
Eluent: water / methanol = 8/2 (volume ratio) (containing 0.05M NaNO ₃ )
Flow rate: 1 ml / min
Sample concentration: 0.25% by weight
Injection volume: 100 μl
However, when the sample does not dissolve in the above eluent, the measurement is performed under the following conditions using dimethylformamide (containing 0.01 M of LiBr) as the eluent.
Measuring machine: HLC-8320GPC, column manufactured by Tosoh Corporation: Guardcolumn α, TSKgel α-M
Eluent: dimethylformamide (containing 0.01M LiBr)
Flow rate: 1 ml / min
Sample concentration: 0.125% by weight
Injection volume: 100 μl

The colloid equivalent value of the copolymer (M) is preferably 1. from the viewpoint of formation of a complex of the copolymer (M), the water-soluble COD component and the salt (S), and the water solubility of the complex. 0 to 4.5, more preferably 1.2 to 4.3.
The colloid equivalent value is adjusted to a desired range by adjusting the molar ratio of the monomer (m1) having a cationic functional group and the monomer (m2) having no cationic functional group, which constitute the copolymer (M). be able to.

The colloid equivalent value of the copolymer (M) can be determined by the following colloid titration method. The subsequent measurements are performed at room temperature (about 20 ° C.).
(1) Preparation of sample solution for measurement (50 ppm aqueous solution of sample) 0.2 g of copolymer (M) was precisely weighed and placed in a 200 ml Erlenmeyer flask, and the total weight (total weight of sample and ion-exchanged water) was 100 g. After ion-exchanged water was added to the mixture, the mixture was stirred for 3 hours with a magnetic stirrer (a cylindrical magnet having a length of 40 mm and a diameter of 5 mm, rotation speed of 1,000 rpm) for 3 hours to be completely dissolved, and 0.2% by weight. Prepare a solution of 10 ml of the prepared solution is placed in a 500 ml beaker, ion-exchanged water is added so that the total weight (total weight of the solution and the ion-exchanged water) is 400 g, and the magnetic stirrer (rotational speed: 1,000 to 1, 1) is added again. (200 rpm) for 30 minutes to obtain a uniform measurement sample.
(2) Measurement of Colloid Equivalent Value of Copolymer (M) 100 g of a sample solution for measurement was placed in a 200 ml conical beaker, and a 0.5% by weight aqueous sulfuric acid solution was gradually added thereto while stirring with a magnetic stirrer (500 rpm). , PH = 3. Next, 2-3 drops of a toluidine blue indicator (TB indicator) are added, and titration is performed with an N / 400 polyvinyl potassium sulfate (N / 400 PVSK) reagent. The titration rate is 2 ml / min, and the point at which the measurement sample changes color from blue to magenta and the magenta color is held for 30 seconds is the end point.
(3) Blank test The same operation as in the above (2) is performed except that 100 g of ion-exchanged water is used instead of the measurement sample.
(4) Calculation method Colloid equivalent value (meq / g) of copolymer (M) = (1/2) × (titer of sample−titer of blank test) × (titer of N / 400 PVSK)

The water treatment agent (P1) preferably further contains water in addition to the copolymer (M) from the viewpoint of operability (handling properties), and is in the form of an aqueous solution or dispersion of the copolymer (M). Preferably, there is.
When containing water, the content of the copolymer (M) in the aqueous solution or dispersion is preferably from 5 to 80% by weight, more preferably from the viewpoint of handleability, based on the total weight of the water treatment agent (P1). Is from 10 to 75% by weight, particularly preferably from 15 to 70% by weight.

When the water treatment agent (P1) contains water, the pH of the water treatment agent (P1) at 20 ° C. is preferably from 2 to 10, and more preferably from the viewpoint of the stability of the copolymer (M). Is 3 to 9, particularly preferably 5 to 8.
In order to adjust pH, inorganic acids (hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, etc.), inorganic solid acidic substances (acidic sodium phosphate, acidic oxalate, ammonium chloride, ammonium sulfate, ammonium bisulfate, sulfamic acid, etc.), organic acids (Eg, oxalic acid, succinic acid, and malic acid), inorganic alkaline substances (eg, sodium hydroxide, potassium hydroxide, ammonia, etc.) and organic alkaline substances (eg, guanidine, etc.) can be added.

The water treatment agent (P2) in the present invention is a water treatment agent containing at least one salt (S) selected from the group consisting of silicates, phosphates and borates. By using the water treatment agent (P2), the water-soluble COD component can be stably reduced even under conditions where the amount of the water treatment agent (P1) is more than the optimum amount.
As the salt (S), one type may be used alone, or two or more types may be used in combination.

Examples of the silicate include alkali metal salts or alkaline earth metal salts of silicic acid and alkali metal salts or alkaline earth metal salts of condensed silicic acid. Preferred as silicates are lithium silicate, sodium silicate, potassium silicate and calcium silicate, more preferably sodium silicate. The properties of the silicate may be solid or aqueous solution, and an aqueous solution of sodium silicate (No. 1, No. 2, No. 3) or so-called water glass may be used.
Examples of the phosphate include alkali metal salts or alkaline earth metal salts of phosphoric acid and alkali metal salts or alkaline earth metal salts of condensed phosphoric acid (such as polyphosphoric acid and metaphosphoric acid). Preferred as phosphates are monosodium phosphate, disodium phosphate, trisodium phosphate, potassium hydrogen phosphate and sodium polyphosphate, more preferably trisodium phosphate.
Examples of the borate include alkali metal salts or alkaline earth metal salts of boric acid, alkali metal salts or alkaline earth metal salts of polyboric acid, and hydrates thereof. Preferred as borate salts are trisodium borate, sodium metaborate and sodium tetraborate, more preferably sodium tetraborate decahydrate.

  The water treatment agent (P2) preferably further contains water in addition to the salt (S) from the viewpoint of operability (handling property). When the water treatment agent (P2) contains water, the water content is preferably 40 to 95% by weight, more preferably 60 to 90% by weight, based on the total weight of the water treatment agent (P2).

  The water treatment agents (P1) and (P2) can contain an organic coagulant and an inorganic coagulant within a range not to impair the effects of the present invention, in order to further improve the performance of removing water-soluble COD components. .

Examples of the organic coagulant include a polycondensate of epihalohydrin and an amine and its hydrochloride, a polycondensate of epihalohydrin and an alkylenediamine and its hydrochloride, polyethyleneimine and its hydrochloride, alkylene dihalide-alkylene polyamine polycondensate and The hydrochloride, aniline-formaldehyde polycondensate and its hydrochloride, polyvinylbenzyltrimethylammonium chloride, polyvinylpyridine and its hydrochloride, (di) methyldi (meth) allylammonium chloride, and polyvinylimidazoline and its hydrochloride are exemplified.
Examples of the inorganic coagulant include coagulants such as aluminum sulfate, polyaluminum chloride, ferric chloride, ferric polysulfate and slaked lime. The organic coagulant and the inorganic coagulant may be used alone or in combination of two or more.

  The water treatment agents (P1) and (P2) used in the water treatment agent method of the present invention are optionally defoaming agents, chelating agents, pH adjusters, antioxidants, as long as the effects of the present invention are not impaired. One or two or more additives selected from the group consisting of agents, ultraviolet absorbers and preservatives can be contained.

  Examples of the antifoaming agent include silicone oil (for example, dimethylpolysiloxane having Mn of 100 to 100,000), mineral oil (for example, spindle oil and kerosene), and metal soap having 12 to 22 carbon atoms (for example, calcium stearate).

  Examples of the chelating agent include aminocarboxylic acids having 6 to 12 carbon atoms (e.g., ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid and triethylenetetraminehexaacetic acid), polyvalent carboxylic acids [e.g., maleic acid, Polyacrylic acid (Mn 1,000 to 10,000) and isoamylene-maleic acid copolymer (Mn 1,000 to 10,000)], a hydroxycarboxylic acid having 3 to 10 carbon atoms (for example, citric acid, gluconic acid, lactic acid and Malic acid), condensed phosphoric acid (eg, tripolyphosphoric acid and trimetaphosphoric acid) and salts thereof [eg, alkali metal (eg, sodium and potassium) salts, alkaline earth metal (eg, calcium and magnesium) salts, ammonium salts, C 1 -C 1 20 Alkylamine (e.g. methylamine, ethylamine and octylamine) salts and alkanolamine (e.g. mono-, - di - or triethanolamine) having 2 to 12 carbon atoms salts], and the like.

  Examples of the pH adjuster include caustic alkali (eg, caustic soda), amine (eg, mono-, di- or triethanolamine), inorganic acid (salt) [eg, inorganic acid (eg, hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, sulfamic acid and Carbonic acid) and salts of these metals [e.g., alkali metals (same as above) and alkaline earth metals (same as above)] (e.g., sodium carbonate, potassium carbonate, sodium sulfate, sodium hydrogen sulfate and monosodium phosphate) and ammonium salts (Eg, ammonium carbonate and ammonium sulfate)], organic acids (salts) [eg, organic acids (eg, carboxylic acids, sulfonic acids, phenols) and their metal (same as above) salts (eg, sodium acetate, sodium lactate) and ammonium salts (For example, ammonium acetate and ammonium lactate)].

  Examples of the antioxidant include phenol compounds such as hydroquinone, methoxyhydroquinone, catechol, 2,6-di-t-butyl-p-cresol (BHT), and 2,2′-methylenebis (4-methyl-6-t-butylphenol). )], Sulfur-containing compounds [eg thiourea, tetramethylthiuram disulfide, dimethyldithiocarbamic acid and salts thereof [eg metal (same as above) and ammonium salts]], sodium sulfite, sodium bisulfite, sodium thiosulfate, Mercaptobenzothiazole and its salts (same as above), dilauryl 3,3'-thiodipropionate (DLTDP), distearyl 3,3'-thiodipropionate (DSTDP)], phosphorus-containing compounds [for example, triphenylphos Fight, triethyl phosphite, Sodium phosphate, sodium hypophosphite, triphenyl phosphite (TPP) and triisodecyl phosphite (TDP)] and nitrogen-containing compounds [for example, amines such as octylated diphenylamine, Nn-butyl-p-aminophenol and N, N-diisopropyl-p-phenylenediamine), urea, guanidine, and the above-mentioned inorganic acid salts of guanidine].

Examples of the ultraviolet absorber include benzophenone compounds (for example, 2-hydroxybenzophenone and 2,4-dihydroxybenzophenone) and salicylate compounds (for example, phenyl salicylate and 2,4-di-t-butylphenyl-3,5-di-t). -Butyl-4-hydroxybenzoate), benzotriazole compounds [e.g. (2'-hydroxyphenyl) benzotriazole and (2'-hydroxy-5'-methylphenyl) benzotriazole] and acrylic compounds [e.g. ethyl-2-cyano- 3,3-diphenyl acrylate and methyl-2-carbomethoxy-3- (paramethoxybenzyl) acrylate].
Preservatives include, for example, benzoic acid, p-hydroxybenzoic acid esters and sorbic acid.

The total amount of the additives used in the water treatment agent (P1) is preferably 0 to 40% by weight, more preferably 0 to 20% by weight, based on the weight of the copolymer (M).
The amount of each of the additives used in the water treatment agent (P1) is preferably 0 to 5% by weight, more preferably 1 to 3% by weight, based on the weight of the copolymer (M). The chelating agent is preferably 0 to 30% by weight, more preferably 2 to 10% by weight, the pH adjuster is preferably 0 to 10% by weight, more preferably 1 to 5% by weight, an antioxidant and an ultraviolet absorber. And the preservative is preferably 0 to 5% by weight, more preferably 0.1 to 2% by weight.

The total amount of the additives used in the water treatment agent (P2) is preferably 0 to 40% by weight, more preferably 0 to 20% by weight, based on the total weight of the salt (S).
The amount of each of the additives used in the water treatment agent (P2) is preferably 0 to 5% by weight, more preferably 1 to 3% by weight, based on the weight of the copolymer (M). The chelating agent is preferably 0 to 30% by weight, more preferably 2 to 10% by weight, the pH adjuster is preferably 0 to 10% by weight, more preferably 1 to 5% by weight, an antioxidant and an ultraviolet absorber. And the preservative is preferably 0 to 5% by weight, more preferably 0.1 to 2% by weight.

The water treatment agent (P1) is used to treat various types of factory wastewater (paper pulp, dyeing, automobile, metal processing, steelmaking, food, gravel collection, wastewater from semiconductor-related and cleaning industries, etc.), sewage, and factory wastewater. By adding to the organic sludge or inorganic sludge generated in the above, a unique water-soluble COD reduction effect, a clarity improvement effect of the filtrate (decolorization), a cake generation amount and a cake water content reduction effect which have not existed before. Show.
The water treatment agent (P2) precipitates the copolymer (M) in (P1) added excessively in the waste water, and stabilizes the water-soluble COD reduction effect. Furthermore, even when the added amount of (P1) is small, a complex of the dissolved water-soluble COD component and the copolymer (M) in (P1) is precipitated, and the water-soluble COD reduction effect is exhibited. .

The water treatment method of the present invention is a water treatment method including a step of adding water (sludge and wastewater, etc.) to be treated with the water treatment agent (P1) and the water treatment agent (P2). Such methods (1) to (3) are mentioned.
(1) A method of adding and mixing the water treatment agents (P1) and (P2) to sludge or wastewater, adjusting the pH if necessary, and then separating the precipitate into solid and liquid.
(2) Add and mix the water treatment agents (P1) and (P2) to sludge or wastewater, adjust the pH as needed, and then add and mix a polymer flocculant to form coarse flocs. And then performing a solid-liquid separation step.
(3) Add and mix the water treatment agents (P1) and (P2) to the sludge or wastewater, add and mix an organic coagulant and / or an inorganic coagulant, and adjust the pH as needed. A method of performing a step of adding and mixing a polymer flocculant to form a coarse floc, and further performing a step of solid-liquid separation.

  In each of the above methods, the method of adding the water treatment agent (P1) and the water treatment agent (P2) to the water to be treated is not particularly limited, and the water treatment agent (P1) and the water treatment agent (P2) are treated. The water treatment agent (P1) and the water treatment agent (P2) may be separately added to the target water, or may be added in advance as a water treatment agent (P).

When the water treatment agent (P1) and the water treatment agent (P2) are previously mixed, the copolymer (M) and the salt (S) contained in the water treatment agent (P2) may form a complex and become cloudy. However, it can be used without any problem by uniformly dispersing it immediately before use.
The method of mixing the water treatment agent (P1) and the water treatment agent (P2) is not particularly limited, and for example, they may be mixed using a stirrer in a container such as a bucket.

  The pH of the water to be treated after adding the water treatment agent (P1) and the water treatment agent (P2) to the water to be treated is preferably 1 to 9, more preferably 2 to 7, particularly preferably 3 to 6. It is. Within this range, the effects of the present invention, such as a reduction in water-soluble COD, can be further exhibited.

  Among the processing methods (1) to (3), the processing methods (2) and (3) are preferable from the viewpoint of forming coarser flocs and facilitating solid-liquid separation.

  As a method of performing the solid-liquid separation step, for example, gravity sedimentation, membrane filtration, column filtration, pressure flotation, a concentrator (eg, a thickener) and a dehydrator (eg, a centrifuge, a belt press dehydrator, and a filter press) Dehydrator etc.) can be used. When the pH of the sludge or wastewater is low and the copolymer (M) in the water treatment agent (P1) does not dissolve, the pH of the sludge or wastewater is adjusted to 4 to 9 before the addition of the water treatment agent (P1). It is preferable to adjust it.

Examples of the organic coagulant and the inorganic coagulant in the treatment method (3) include the same organic coagulants and inorganic coagulants that may be contained in the water treatment agents (P1) and (P2). May be used alone or in combination of two or more.
When using an organic coagulant or an inorganic coagulant, the method of addition is not particularly limited, and in the case of using an organic coagulant and an inorganic coagulant in combination, either one may be added first, or at the same time, You may add what was previously mixed.

  The polymer flocculant used in the above treatment methods (2) and (3) is not particularly limited, and those having a Mw exceeding 1,000,000, which is commonly used as a known polymer flocculant, can be used. Any of a polymer, a nonionic, an anionic and an amphoteric polymer flocculant may be used, or a combination of these may be used.

  Examples of the cationic polymer coagulant include polyethyleneimine, Mannich-modified poly (meth) acrylamide, homopolymer of dialkylaminoethyl (meth) acrylate quaternary compound, and other monomers such as (meth) acrylamide. Copolymers and other copolymers containing the above-mentioned cationic monomer (m11) as a constituent unit and having a Mw of more than 1,000,000 are exemplified.

Examples of the nonionic polymer coagulant include polyacrylamide and the like having a Mw of more than 1,000,000.
Examples of the anionic polymer coagulant include sodium poly (meth) acrylate, hydrolyzate of poly (meth) acrylamide, (meth) acrylamide / sodium (meth) acrylate copolymer, (meth) acrylamide / (meth) Sodium acrylate / 2-acrylamide-2-methylpropane-1-sodium sulfonate copolymer, (meth) acrylamide / 2-acrylamido-2-methylpropane-1-sodium sulfonate copolymer and other anionic compounds as described above A (co) polymer containing a monomer (m22) having a Mw of more than 1,000,000 is exemplified.

  Examples of the amphoteric polymer flocculant include a cationic monomer [dialkylaminoethyl (meth) acrylate quaternary compound and the other cationic monomer (m11) and the like] and an anionic monomer [(meth) acrylic acid (salt), 2- ( Acrylamide-2-methylpropane-1-sulfonic acid (salt), etc.] and, if necessary, a copolymer with a nonionic monomer (eg, acrylamide) having a Mw of more than 1,000,000.

When the water treatment agent (P1) is added, it may be added as it is, or may be further diluted with water. When the water treatment agent (P1) is diluted with water, the concentration of the copolymer (M) is preferably 0.01 to 20% by weight, more preferably, based on the total weight of the water treatment agent (P1) and the dilution water. Is 0.1 to 5% by weight.
The method of dilution is not particularly limited. For example, a predetermined amount of the copolymer (M) is added to a pre-measured water while stirring using a known stirrer (such as a jar tester), and the water is added for several hours (about A stirring method (about 1 to 4 hours) can be employed.

  The amount of the water treatment agent (P1) used depends on the type of water to be treated, the content of particles suspended in the water to be treated, the amount of water-soluble COD components, and the like, and is not particularly limited. From the viewpoint of COD reduction performance, the weight of the copolymer (M) added to the water to be treated is preferably 1 mg to 10 g, more preferably 3 mg to 8 g, per 1 L of the water to be treated. The amount is particularly preferably from 5 mg to 5 g, most preferably from 5 mg to 3 g.

  The weight of the water treatment agent (P2) added is the weight ratio of the salt (S) in the treatment agent (P2) to the weight of the copolymer (M) in the treatment agent (P1) [(S) / (M)]. Is preferably from 0.2 to 30, more preferably from 0.5 to 20, and particularly preferably from 1.5 to 11.

  In the water treatment method of the above-mentioned treatment method (3), when an inorganic coagulant and / or an organic coagulant is further added to wastewater, the amount of these used depends on the type of sludge or wastewater, the size of suspended particles, It depends on the amount of total sludge and water-soluble COD components in wastewater.

The amount of the inorganic coagulant used is preferably 0.001 to 1% by weight, more preferably 0.005 to 0.8% by weight, particularly preferably 0.01 to 0.5% by weight, based on the weight of the wastewater. It is. When it is 0.001% by weight or more, the water-soluble COD reduction performance is further improved, and when it is 1% by weight or less, the amount of sludge generation can be reduced.
The amount of the organic coagulant used is preferably 0.0001 to 0.5% by weight, more preferably 0.0003 to 0.3% by weight, based on the weight of the wastewater, from the viewpoint of the water-soluble COD reduction performance. Particularly preferably, it is 0.0005 to 0.1% by weight.

In the treatment methods (2) and (3), there is no particular limitation on the method of adding the polymer flocculant to the sludge or wastewater treated with the water treatment agent of the present invention. However, from the viewpoint of uniform mixing, a method in which the polymer flocculant is converted into an aqueous solution and then added to sludge or wastewater is preferred. When the polymer flocculant is used as an aqueous solution, the concentration of the polymer flocculant is preferably 0.05 to 1% by weight, more preferably 0.1 to 0.5% by weight.
The dissolution method and the dilution method after dissolution are not particularly limited, and are the same as in the case of the organic coagulant. In particular, when dissolving the powdery polymer flocculant in water, if the polymer flocculant is added at once, it becomes difficult to dissolve it in water because it causes a clogging, so it is preferable to gradually add the polymer flocculant.

  In the treatment methods (2) and (3), the amount of the polymer flocculant used when adding to the sludge or wastewater is determined by the type of the sludge or wastewater, the content of suspended particles, and the molecular weight of the polymer flocculant. From the viewpoint of general coagulation performance, it is preferably 0.0001 to 0.5% by weight, more preferably 0.0002 to 0.3% by weight, and particularly preferably 0.0001 to 0.5% by weight based on the weight of sludge or wastewater. It is 0.0003-0.2% by weight, most preferably 0.0004-0.1% by weight.

  Although the COD of the wastewater treated in (P1) and (P2) may be directly measured to confirm the effect of removing water-soluble COD in the present invention, it is commonly used in the field of wastewater treatment as an alternative to monitoring COD. Therefore, the effect of removing COD can be evaluated by TOC (total organic carbon) which is simpler than the measurement of COD. In the following examples, both COD and TOC are described.

  Hereinafter, the present invention will be described specifically with reference to Examples, but the present invention is not limited to these Examples. The parts in the examples are parts by weight.

<Production Example 1>
190 parts of isopropyl alcohol (hereinafter abbreviated as “IPA”) and 69 parts of ion-exchanged water are charged into a four-necked flask equipped with a stirrer, a temperature sensor, a cooling tube, a dropping funnel and a mantle heater, and heated under reflux with stirring. I let it. A mixed solution of 80 parts of IPA, 20 parts of ion-exchanged water, and 0.7 parts of azobisisobutyronitrile (hereinafter abbreviated as “AIBN”) as an initiator solution from the dropping port, and a monomer solution (m11) from the other dropping port. A homogeneous mixture of -1) 352 parts, (m2-2) 48 parts, IPA 180 parts, and ion-exchanged water 60 parts was simultaneously dropped into the flask for 4 hours while stirring the inside of the flask at 80 to 85 ° C. After dropping, the mixture was aged at the same temperature for 2 hours, and a homogeneous mixture of 80 parts of IPA, 20 parts of ion-exchanged water, and 2.0 parts of AIBN was dropped into a flask at 80 to 85 ° C. for 1 hour, and aged at the same temperature for 180 minutes. . Thereafter, 465 parts of ion-exchanged water was charged into the flask, and the temperature was raised to 100 ° C. to remove IPA, thereby obtaining 1000 parts of a water treatment agent (P1-1) containing a copolymer (M-1). . The solid content of (P1-1) was 40.0% by weight, the pH was 4.5, the Mw of the copolymer (M-1) was 180,000, and the colloid equivalent value was 4.1.

<Production Examples 2 to 9 and Comparative Production Example 1>
Water treatment agents (P1-2) to (P1-9) and a water treatment agent for comparison were prepared in the same manner as in Production Example 1 except that the types and amounts of raw materials used were changed to those shown in Table 1. (P1′-1) was obtained. Table 1 shows the solid content concentration of the obtained water treatment agent, the molar ratio of (m1) to (m2) in the polymer (M), the colloid equivalent value of the polymer (M), and Mw.

The contents of the raw materials and symbols described in Table 1 are as follows.
(1) Monomer having cationic functional group (m1)
(M11-1): dimethylaminoethyl methacrylate methyl chloride quaternary salt (m11-2): dimethylaminoethyl acrylate methyl chloride quaternary salt (m11-3): dimethylaminoethyl acrylate benzyl chloride quaternary salt (m11-4) : Dimethylaminopropylacrylamidomethyl chloride quaternary salt (m12-1): diallyldimethylammonium chloride (2) monomer having no cationic functional group (m2)
(M2-1): acrylamide (m2-2): styrene (m2-3): lauryl methacrylate (m2-4): acrylic acid

<Production Example 10>
Sodium silicate solution No. 3 purchased from Kishida Chemical was dissolved in ion-exchanged water so as to have a solid content concentration of 20% by weight to obtain a water treatment agent (P2-1).

<Production Example 11>
Trisodium phosphate (manufactured by Fujifilm Wako Pure Chemical Co., Ltd., reagent) was dissolved in ion-exchanged water so as to have a solid concentration of 15% by weight to obtain a water treatment agent (P2-2).

<Production Example 12>
Sodium tetraborate decahydrate (reagent, manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was dissolved in ion-exchanged water so as to have a solid concentration of 20% by weight to obtain a water treatment agent (P2-3).

<Production Example 13>
17.35 parts of the water treatment agent (P1-1) obtained in Production Example 1 and 82.65 parts of the water treatment agent (P2-1) obtained in Production Example 10 were weighed and mixed in a container. The obtained white suspension was used as a water treatment agent (P-1) in which the water treatment agent (P1-1) and the water treatment agent (P2-1) were previously mixed.

<Example 1>
A 500 ml wastewater from Chemical Plant A containing an anionic surfactant was collected in a beaker, and an aqueous solution (P1-1) of a water treatment agent (P1-1) diluted 50-fold with ion-exchanged water in advance under stirring was used. 6.5% (solid content = 52.5 mg) and stirred for 1 minute to obtain a solution in which the solid content of (P1-1) was 105 mg per 1 L of waste water. 0.9375 g of (P2-1) [addition amount of solid content of (P2-1) to 1 L of waste water = 375 mg] was added. After 3 minutes, the pH is adjusted to 7.0 by dropwise addition of a 1% by weight aqueous sulfuric acid solution while stirring is continued, and then, while stirring, 0.1% of Sanfloc CE-706P as a polymer flocculant is added. A 2% by weight aqueous solution was added in such an amount that the solid content concentration became 10 ppm, and the mixture was stirred for 3 minutes and then allowed to stand for 5 minutes. Regarding the filtrate obtained by filtering the standing supernatant liquid with a filter paper (No. 5C), the TOC was determined according to the COD _Mn analysis method described in JIS K0102: 2016, and the TOC was determined as a multi N / C 3100 manufactured by Analytical Jena Japan Co., Ltd. It measured using. COD was 23 mg / L and TOC was 32 mg / L.
The Mw of Sunfloc CE-706P as the polymer flocculant used was too high to be measured by the above-mentioned measuring method in the present invention, and the Mw calculated from the intrinsic viscosity was about 9 million.

<Examples 2 to 7>
The same treatment as in Example 1 was carried out except that the types and amounts of the water treatment agents (P1) and (P2) were changed to those shown in Table 2, and the COD and TOC of the supernatant were measured. The results are shown in Table 2.
The amounts of the water treatment agents (P1) and (P2) described in Table 2 and Tables 3 and 4 described below are based on the solid content of (P1) or (P2) with respect to 1 L of wastewater (unit: mg). ).

<Comparative Example 1>
In Example 1, without adding the water treatment agents (P1-1) and (P2-1), a 1% by weight aqueous sulfuric acid solution and Sunfloc CE-706P, the COD and TOC of the wastewater of Factory A itself were measured. COD was 79 mg / L and TOC was 120 mg / L.

<Comparative Examples 2 to 7>
The amount of the water treatment agent (P1) was changed to that shown in Table 2, and the same treatment as in Example 1 was carried out except that the water treatment agent (P2) was not used, and the COD and TOC of the supernatant were measured.

  The graph which plotted the value of COD with respect to the value of TOC in Comparative Examples 1-4 is shown in FIG. FIG. 1 shows that TOC has a high correlation with COD and can be an alternative index of COD.

  FIG. 2 is a graph in which the values of COD are plotted with respect to the amount of the solid component (P1) for Examples 1 to 5 and Comparative Examples 1 to 6. In the case of the comparative example in which (P2) was not used, the COD decreased until the addition amount of (P1) was 210 mg, and the COD increased when the addition amount was further increased, and the addition amount of (P1) has an optimum point. You can see that. On the other hand, in the case of the example in which (P2) is used in combination, even when the amount of (P1) exceeding the optimum addition amount is used, no increase in COD is observed, and a stable COD reduction effect is exhibited. I understand.

For Examples 1 to 7 and Comparative Examples 2 to 7, the COD removal rate and the TOC removal rate were calculated from the obtained values of COD and TOC based on the following formulas, and the water-soluble COD component removal performance of the wastewater was calculated. Was evaluated. The obtained results are shown in Table 2.
COD removal rate (%) = (COD value before processing−COD value after processing) / COD value before processing × 100
TOC removal rate (%) = (value of TOC before processing−value of TOC after processing) / value of TOC before processing × 100
However, the values of COD and TOC before the treatment in the above formula are 79 mg / L and 120 mg / L, respectively, as described in Comparative Example 1.
Table 2 shows the excess addition ratio of the water treatment agent (P1) to the wastewater to be treated and the weight ratio of (P2) to (P1) calculated from the following formula.
Excessive addition rate (% by weight) of (P1) = [addition amount of (P1) −optimum addition amount of (P1)] / optimum addition amount of (P1) × 100

<Examples 8 to 16>
After previously determining the optimum addition amount for each of the water treatment agents (P1) described in Table 3, the supernatant was treated in the same manner as in Example 1 for the optimum addition amount and the excess addition amount described in Table 3, respectively. Was measured for COD and TOC. Table 3 shows the measured values of COD and TOC, the excess addition rate of (P1), the COD removal rate, the TOC removal rate, and the weight ratio of (P2) to (P1).
In addition, in each Example of Table 3 and each Comparative Example of Table 4 described later, the result in the case of the optimum addition amount is shown in the left column, and the result in the case of excessive addition is shown in the right column.
Further, in Example 8, the same treatment as in Example 5 was performed except that the addition order of the water treatment agents (P1-1) and (P2-1) in Example 5 was changed.

<Example 17>
(P1-1) and (P2-1) separately added in Example 5 were mixed with the water treatment agents (P1-1) and (P2-2) produced in Production Example 13 in advance. The same treatment as in Example 5 was performed except that -1) was used. The breakdown of the solid content of 852 mg of (P-1) in Table 3 is (P1-1) = 252 mg and (P2-1) = 600 mg. The results are shown in Table 3.

<Example 18>
The same treatment as in Example 5 was carried out except that the polymer flocculant "Sanfloc CE-706P" was not used. The results are shown in Table 3.

<Comparative Examples 8 to 15>
The treatment was performed in the same manner as in Example 1 except that the type and amount of the water treatment agent (P1) were changed to those shown in Table 4 and the water treatment agent (P2) was not used. The results are shown in Table 4.

<Comparative Examples 16 to 19>
The treatment was carried out in the same manner as in Example 1 except that the kind and amount of the water treatment agent (P2) were changed to those shown in Table 4, and the water treatment agent (P1) was not used. The results are shown in Table 4.

<Comparative Examples 20 to 22>
The treatment was carried out in the same manner as in Example 1, except that the types and amounts of the water treatment agents (P1) and (P2) were changed to those shown in Table 4. The results are shown in Table 4.

The contents of the water treatment agents (P1'-2) and (P1'-3) in Table 4 are as follows.
(P1'-2): Sanyo Kasei Kogyo Co., Ltd. cationic polymer flocculant "Sanfloc CES-668" (Mw cannot be measured because the molecular weight is too high in the above measurement method in the present invention: Mw converted from intrinsic viscosity) Is about 4 million)
(P1′-3): polyallylamine hydrochloride [“PAA-HCl-3L” manufactured by Nitto Bo Co., Ltd.]

  In Examples 8 to 18, COD removal was obtained in any combination of water treatment agents (P1) and (P2), both in the case of the optimum addition amount of (P1) and in the case of an excess addition ratio of (P1) of 20% by weight. It can be seen that the water-soluble COD component can be removed stably even under the excessive addition condition of (P1). On the other hand, in Comparative Examples 8 to 15 in which the water treatment agent (P2) was not used, the COD removal rate and the TOC removal rate in the case of the (P1) excess addition rate of 20% by weight were drastically reduced. In Comparative Examples 16 to 19 in which the agent (P1) was not used, the COD removal rate and the TOC removal rate were extremely low, indicating that there was almost no effect of removing water-soluble COD. Furthermore, in Comparative Examples 20 to 22 using the water treatment agent that does not satisfy the condition (P1) in the present invention, both in the case of the optimal addition amount of (P1) and in the case of the excess addition ratio of 20% by weight of (P1). It can be seen that the water-soluble COD component has increased and there is no COD removal effect.

The water treatment method of the present invention contains an organic component such as sewage or industrial wastewater because the water-soluble COD component can be removed with an added amount of a water treatment agent in a wide range as compared with the conventional method. It can be used as a wastewater treatment method.
Also, it is suitably used as a muddy water treatment at a civil engineering site, a treatment for promoting sedimentation and separation of muddy water at the time of dredging and a wastewater treatment method in a papermaking process.

Claims (7)

  Water treatment agent containing a copolymer (M) having a weight average molecular weight of 500 to 1,000,000 obtained by polymerizing a monomer (m1) having a cationic functional group and a monomer (m2) having no cationic functional group. A step of adding (P1) and a water treatment agent (P2) containing at least one salt (S) selected from the group consisting of silicates, phosphates and borates to the water to be treated. Water treatment method. The monomer (m1) having a cationic functional group is a cationic monomer (m11) represented by the general formula (1) and / or a cationic monomer (m12) represented by the general formula (2). 2. The water treatment method according to 1.

^{_{CH 2 = C (R 1)}} -CO-X-Q-N + (R 2) 3 · Z - (1)

[In the formula, R ¹ is a hydrogen atom or a methyl group, three R ² are each independently a hydrogen atom, an alkyl group or a benzyl group having 1 to 22 carbon atoms, X is an oxygen atom or NH, and Q is 1 to 3 carbon atoms. The alkylene group 6 and Z ^- represent a conjugate base of Bronsted acid or an anionic group derived from a quaternizing agent. ]

^{_{(CH 2 = C (R 3}} ) -CH 2) 2 -N + (R 4) 2 · Z - (2)

[In the formula, R ³ is a hydrogen atom or a methyl group, two R ⁴ are each independently a hydrogen atom, an alkyl group or a benzyl group having 1 to 22 carbon atoms, and Z ⁻ is a conjugate base or quaternization of Bronsted acid. Represents an anionic group derived from the agent. ]   The monomer (m2) having no cationic functional group includes alkyl (meth) acrylate having 4 to 30 carbon atoms (m211), unsaturated hydrocarbon having 2 to 30 carbon atoms (m212), and 3 to 30 carbon atoms (m2). The water treatment method according to claim 1 or 2, wherein the water treatment method is at least one monomer selected from the group consisting of a (meth) acrylamide-based monomer (m213) and an unsaturated carboxylic acid (anhydride) having 2 to 30 carbon atoms (m221).   The water treatment method according to any one of claims 1 to 3, wherein a molar ratio of the monomer (m1) and the monomer (m2) is 10:90 to 99.9: 0.1.   The water treatment method according to any one of claims 1 to 4, wherein a colloid equivalent value of the copolymer (M) is 1.0 to 4.5.   After performing the step of adding the water treatment agent (P1) and the water treatment agent (P2) to the water to be treated, a step of further adding a polymer flocculant having a weight average molecular weight exceeding 1,000,000, The water treatment method according to any one of claims 1 to 5, comprising a step of solid-liquid separation.   Water treatment agent containing a copolymer (M) having a weight average molecular weight of 500 to 1,000,000 obtained by polymerizing a monomer (m1) having a cationic functional group and a monomer (m2) having no cationic functional group. A water treatment agent (P) comprising (P1) and a water treatment agent (P2) containing at least one salt (S) selected from the group consisting of silicates, phosphates and borates.

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