JP7152359B2 - Water treatment agent and water treatment method - Google Patents

Description

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

Conventional methods for removing water-soluble COD components contained in factory wastewater include activated carbon treatment, ultraviolet irradiation, ozone treatment, and Fenton treatment using a combination of ferrous sulfate and hydrogen peroxide. However, it is difficult to say that all of them are widely used due to their high processing costs.
In addition, a method of adding a polymer flocculant after adding an inorganic coagulant to form flocculated flocs and then treating by flocculation sedimentation or flocculation flotation is adopted (see, for example, Patent Document 1). The inorganic coagulant neutralizes the surface charge of the suspended matter in the waste water by its charge neutralizing action, and has the action of coagulating the suspended matter while reducing the repulsive force between the suspended matter. Suspended solids are removed from the waste water by solid-liquid separation of flocculated flocs formed by adding a polymer flocculant thereto. However, with such treatment, compounds that do not become ions even when dissolved in water, such as nonionic surfactants and polyvinyl alcohol, cannot be sufficiently removed from sludge or industrial wastewater. There was a problem of leaving . In addition, the presently used method of using an inorganic coagulant in the primary treatment requires a huge amount of addition, so there is also the problem that the amount of sludge after solid-liquid separation increases and the treatment cost rises.

In recent years, the suppression of COD (chemical oxygen demand) due to the tightening of wastewater regulations is one of the major themes in environmental problems, and early development of a water treatment agent having a high COD reduction effect at low cost is desired. In order to meet these demands, various polymeric water treatment agents have been developed for the purpose of more effective treatment. For example, an organic fine particle having a cationic functional group (see, for example, Patent Document 2), an organic coagulant obtained by mixing two cationic polymers (see, for example, Patent Document 3), a cationic monomer and a hydrophobic monomer. A water treatment agent using an organic coagulant (see, for example, Patent Document 4) composed of a polymer obtained by copolymerizing a solid has been proposed.

JP 2015-150489 A Japanese Patent No. 4923834 Japanese Patent No. 5709086 Japanese Patent No. 4786569

However, although Patent Documents 1 to 4 are cationic polymers and show an effect on anionic water-soluble COD components, many of them are used in dyeing factories, paper factories, semiconductor factories, automobile factories and food factories. It is difficult to remove the nonionic water-soluble COD component, which is a problem in factory wastewater. Moreover, although the method described in Patent Document 3 reduces the COD of wastewater containing a nonionic surfactant, it is difficult to say that the effect is sufficient.
An object of the present invention is to provide a water treatment agent having excellent removal performance of water-soluble COD components, especially nonionic water-soluble COD components (nonionic surfactants, polyvinyl alcohol, etc.) that are difficult to remove. be.

The present inventors arrived at the present invention as a result of intensive studies to solve the above problems. That is, the present invention
Polymer (A1) containing as constituent monomers anionic monomer (a) represented by general formula (1) and nonionic monomer (b) represented by general formula (2) and/or general formula A water treatment agent (P) containing a polymer (A2) having only the nonionic monomer (b) represented by (2) as a constituent monomer; mixing the water treatment agent (P) with sludge or wastewater It is a water treatment method including the step of

_CH2 =CR1 ^- X ^- .Y ⁺ (1)

[wherein R ¹ is a hydrogen atom or a methyl group, X ^- is COO ^- , SO ₃ ^- , C ₆ H ₄ SO ₃ ^- or CONHC(CH ₃ ) ₂ CH ₂ SO ₃ ^- , and Y ⁺ is It is a monovalent cation. ]

_CH2 =CR2 ^{- COO-} ( _C2H4O ) _n -R3 ( ₂ )

[In the formula, R ² is a hydrogen atom or a methyl group, R ³ is an alkyl group having m carbon atoms, m is an integer of 8 to 30, and n is the value of n/m to the second decimal place. It is a number that gives a value of 0.3 to 2.5 when rounded off by . ]

When the water treatment agent (P) of the present invention is added to water-soluble COD component-containing wastewater for treatment, it has a particularly excellent effect in removing nonionic water-soluble COD components.

The water treatment agent (P) of the present invention contains an anionic monomer (a) represented by the general formula (1) and a nonionic monomer (b) represented by the general formula (2) as constituent monomers. It contains the polymer (A1) and/or the polymer (A2) whose constituent monomers are only the nonionic monomer (b) represented by the general formula (2). Polymers (A1) and (A2) may be used alone or in combination of two or more.

_CH2 =CR1 ^- X ^- .Y ⁺ (1)

_CH2 =CR2 ^{- COO-} ( _C2H4O ) _n -R3 ( ₂ )

R ¹ in general formula (1) is a hydrogen atom or a methyl group, X ^- is COO ^- , SO ₃ ^- , C ₆ H ₄ SO ₃ ^- , or CONHC(CH ₃ ) ₂ CH ₂ SO ₃ ^- , Y ⁺ is a monovalent cation.

Monovalent cations include protons (H ⁺ ), alkali metal ions (sodium ions, potassium ions, lithium ions, etc.), ammonium ions, and the like.
Among these monovalent cations, protons, sodium ions, potassium ions, lithium ions and ammonium ions are preferred from the viewpoint of the solubility of the polymer (A1), and more preferred are protons, sodium ions and is a potassium ion.

Among the anionic monomers (a) represented by the general formula (1), (meth)acrylic acid, vinylsulfonic acid, vinylbenzenesulfonic acid, 2 -acrylamido-2-methylpropanesulfonic acid and alkali metal salts or ammonium salts thereof, more preferably (meth)acrylic acid, 2-acrylamido-2-methylpropanesulfonic acid and alkali metal salts or ammonium salts thereof salts, particularly preferred are (meth)acrylic acid and sodium or potassium salts thereof.
In the present invention, the expression "(meth)acrylic acid" means acrylic acid and/or methacrylic acid.
The anionic monomer (a) represented by the general formula (1) may be used alone or in combination of two or more.

R ² in general formula (2) is a hydrogen atom or a methyl group.
R ³ in the general formula (2) is an alkyl group having m carbon atoms, where m is an integer of 8 to 30, preferably 8 to 24, more preferably 8 to 24, from the viewpoint of the effect of removing nonionic water-soluble COD components. is 12-20. When m is less than 8, hydrophobicity is insufficient, and a water treatment agent having a sufficient effect of removing nonionic water-soluble COD components cannot be obtained.
Specific examples of preferred groups for R ³ include a lauryl group (12 carbon atoms), a cetyl group (16 carbon atoms), a stearyl group (18 carbon atoms), an oleyl group (18 carbon atoms) and an eicosyl group (20 carbon atoms). is mentioned.

n in the general formula (2) is a number whose value is 0.3 to 2.5 when the value of n/m is rounded to the second decimal place. n/m means the ratio of the size of the poly(ethyleneoxy) group, which is a hydrophilic functional group, to the size of R3 ^, which is a hydrophobic functional group. The solubility in water of the combined (A1) and (A2) is in an appropriate range, and a water treatment agent having a sufficient effect of removing nonionic water-soluble COD components can be obtained.
n/m is preferably 0.5 to 2.5 from the viewpoint of water-soluble COD reduction effect.

Specific examples of preferred nonionic monomers (b) represented by formula (2) from the viewpoint of water-soluble COD reduction effect include lauroxypolyethylene glycol (meth)acrylate and stearoxypolyethyleneglycol (meth)acrylate. is mentioned.
In the present invention, the notation of "(meth)acrylate" means acrylate and/or methacrylate.
The nonionic monomer (b) represented by the general formula (2) may be used alone or in combination of two or more.

Weight ratio [(a):( b)] is preferably 10:90 to 98:2, more preferably 30:70 to 90:10, particularly preferably 50:50 to 85:8, most preferably 60:40 to 80:20.
Within this range, in addition to the effect of reducing water-soluble COD, the clarification of the filtrate can be improved and the effect of decolorization, etc., can be improved. get better.

The intrinsic viscosity [η] of the polymers (A1) and (A2) is preferably from 0.010 to 3.0 dl/g, more preferably from the viewpoint of the water-soluble COD reduction performance of the water treatment agent (P). 0.05 to 2.5 dl/g, most preferably 0.10 to 2.0 dl/g. In the present invention, the intrinsic viscosity [η] is a value measured using a 1N—NaNO ₃ aqueous solution as a solvent and measuring at a temperature of 30° C. according to the method described in the Polymer Flocculant Usage Guide (published by Tokyo Sewerage Service Co., Ltd., page 115). be.

The method for producing the polymers (A1) and (A2) is not particularly limited, and radical polymerization methods such as solution dropping polymerization, reverse phase suspension polymerization, photopolymerization, precipitation polymerization and reverse phase emulsion polymerization can be employed. Among these, solution dropping polymerization is preferred from the viewpoint of temperature control and molecular weight control during polymerization.
Examples of the solution dropping polymerization include 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-6-211942), and when an organic solvent is used as the solvent, From the viewpoint of safety in handling and environmental protection, it is preferable to remove the solvent and add water as necessary.

Solvents used in the production of the polymers (A1) and (A2) include, for example, water, alcohols (methanol, ethanol, isopropyl alcohol, etc.), ketones (methyl ethyl ketone, acetone, etc.), tetrahydrofuran (THF), dimethylformamide (DMF). and mixtures thereof and non-polar solvents such as toluene and xylene.
Among these, a mixed solvent of water and alcohol is preferable from the viewpoint of the solubility of the monomer and the initiator and the ease of solvent removal after polymerization, and a mixed solvent of water and isopropyl alcohol is more preferable. be.

Examples of radical polymerization initiators in the radical polymerization method include water-soluble azo initiators [for example, azobisamidinopropane (salt) [for example, 2,2'-azobis(2-methylpropionamidine) dihydrochloride], azobiscyano valeric acid (salt) and 2,2′-azobis[2-(5-methyl-2-imidazolin-2-yl)propane] (salt)], oil-soluble azo initiators (e.g. azobiscyanovaleronitrile, azobis isobutyronitrile and azobiscyclohexanecarbonitrile), water-soluble peroxides [inorganic peroxides (ammonium persulfate, sodium persulfate, hydrogen peroxide, etc.) and organic peroxides (peracetic acid, t-butyl hydroperoxide etc.)], oil-soluble peroxides (eg, benzoyl peroxide, cumene hydroperoxide, di-t-butyl peroxide and di-t-butylperoxyhexahydroterephthalate).

The above peroxides may be used as redox initiators in combination with reducing agents such as bisulfites (e.g. sodium bisulfite, potassium bisulfite and ammonium bisulfite), reducing metal salts [e.g. (II)], tertiary amines [e.g. dimethylaminobenzoic acid (salts) and dimethylaminoethanol], amine complexes of transition metal salts [e.g. pentamethylenehexamine complexes of cobalt(III) chloride and diethylenetriamine complexes 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 0.001 to 20% by weight, more preferably 0.001 to 20% by weight, based on the total weight of the monomers, from the viewpoint of obtaining optimum molecular weights for the polymers (A1) and (A2). 005 to 10% by weight, particularly preferably 0.01 to 5% by weight, most preferably 0.05 to 3% by weight.

A chain transfer agent for radical polymerization may also be used, if necessary. The chain transfer agent for radical polymerization is not particularly limited. Yes, such as methanol, ethanol, isopropyl alcohol, ethylene glycol, propylene glycol, polyethylene glycol (chemical formula weight 106 or more and Mn 50,000 or less) and (poly)ethylene (poly)propylene glycol (chemical formula weight 120 or more and Mn 50,000 or less) ], compounds having one or more amino groups in the molecule [e.g. ammonia and amines (compounds having 1 to 30 carbon atoms, such as methylamine, dimethylamine, triethylamine and propanolamine)], hypochlorous Examples thereof include sodium phosphate and compounds having one or more thiol groups in the molecule.
Among these, sodium hypophosphite and a compound having one or more thiol groups in the molecule are preferred from the viewpoint of molecular weight control.

Compounds having a thiol group in the molecule include the following (1) to (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, inorganic acid (eg, hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid) salts] and mixtures thereof.

(1) monovalent thiol aliphatic thiol having 1 to 20 carbon atoms (e.g. methanethiol, ethanethiol, propanethiol, n-octanethiol, n-dodecanethiol, hexadecanethiol, n-octadecanethiol, 2-mercaptoethanol, mercapto acetic acid, 3-mercaptopropionic acid, 1-thioglycerol, monoethanolamine thioglycolate, 1-thioglycerol, monoethanolamine thioglycolate, thiomaleic acid, cysteine and 2-mercaptoethylamine), C5-20 fats Cyclic thiols (eg, cyclopentanethiol and cyclohexanethiol) and aromatic (aliphatic) thiols having 6 to 12 carbon atoms (eg, benzenethiol, benzylmercaptan and thiosalicylic acid), and the like.

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

When a chain transfer agent for radical polymerization is used, the amount used is preferably 0.001 to 10% by weight, more preferably 0.005, based on the total weight of the monomers, from the viewpoint of obtaining the optimum molecular weight of the polymer. to 5% by weight, particularly preferably 0.01 to 3% by weight, most preferably 0.05 to 1% by weight.

When a salt is used as the anionic monomer (a), it may be polymerized as a salt or a salt may be formed after polymerization. From the viewpoint of polymerizability, a base (sodium hydroxide, potassium hydroxide, etc.) is added after polymerization. It is preferable to form the salt by

The monomer concentration in the monomer solution in solution dropping polymerization is preferably 5 to 90 wt%, more preferably 10 to 80 wt%, particularly preferably 15 to 75 wt%, most preferably 25 wt%, based on the total weight of the monomer solution. ~70% by weight.
If it is 5% by weight or more, residual monomers can be reduced, and if it is 90% by weight or less, it is easy to control the temperature during polymerization.

From the viewpoint of molecular weight control, it is preferable to control the polymerization temperature in the solution dropping polymerization so as to keep a predetermined temperature constant (for example, a predetermined temperature ±5° C.). Although the temperature can be controlled by appropriately heating and cooling the reaction vessel, dropping polymerization below the boiling point of the solvent is preferred because it is easy to keep the predetermined temperature constant. The boiling point of the solvent can be adjusted by the type and pressure of the solvent.
The polymerization temperature is preferably 40 to 190°C, more preferably 50 to 180°C, particularly preferably 60 to 170°C, and most preferably 80 to 150°C, from the viewpoints of ease of temperature control and safety.

The end point of the polymerization can be confirmed when the heat generation due to the polymerization disappears, but the polymerization time is preferably 1 to 24 hours from the point at which the initiation of the polymerization due to heat generation is confirmed from the viewpoint of completing the polymerization and reducing the residual monomer. Yes, more preferably 2 to 12 hours. The above 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 for polymerization, the organic solvent should be replaced with water after desolvation from the viewpoint of contamination of the waste water with the organic solvent and safety of handling when the water treatment agent (P) is used. is preferred. The solvent may be removed by heating under normal pressure, or the solvent may be removed under reduced pressure. As a method for replacing with water, water may be added at any stage before, during or after solvent removal.

Polymers (A1) and (A2) may be insoluble or soluble in water, but from the viewpoint of water-soluble COD reduction effect, 1 g or more should be dissolved in 100 g of water at 25°C and pH 5.0. is preferred, and more preferably 1 to 10 g is dissolved.

The water treatment agent (P) of the present invention preferably contains water in addition to the polymers (A1) and (A2) from the viewpoint of handleability, and is preferably in the form of an aqueous solution or dispersion. When water is contained, the content of the polymers (A1) and (A2) in the aqueous solution or dispersion is preferably 5 to 80% by weight, more preferably 5 to 80% by weight, based on the weight of the aqueous solution or dispersion from the viewpoint of handling. 10 to 75% by weight, particularly preferably 15 to 70% by weight.

When the water treatment agent (P) contains water, the pH of (P) is preferably 2 to 10, more preferably 3 to 9, and particularly preferably 5 to 8 from the viewpoint of stability. Inorganic acids (e.g. hydrochloric acid, sulfuric acid, nitric acid and phosphoric acid), inorganic solid acidic substances (e.g. acid sodium phosphate, acid glaucous nitrate, ammonium chloride, ammonium sulfate, ammonium bisulfate and sulfamic acid), organic acids to adjust pH (eg oxalic acid, succinic acid and malic acid), inorganic alkaline substances (eg sodium hydroxide, potassium hydroxide and ammonia) and organic alkaline substances (eg guanidine) can be added. The above pH is a value measured using a pH meter or the like at room temperature (20° C.) of the water treatment agent (P).

In the water treatment agent (P) of the present invention, an organic coagulant and an inorganic coagulant can be used in combination in order to further improve the removal performance of water-soluble COD components within a range that does not impair the effects of the present invention.
Examples of organic coagulants include a polycondensate of epichlorohydrin and dimethylamine and its hydrochloride, polyallylamine and its hydrochloride, polyethyleneimine and its hydrochloride, polydiallyldimethylammonium chloride, polydiallylmethylamine hydrochloride, and diallyldimethylammonium. Known coagulants such as copolymers of chloride and sulfur dioxide, copolymers of diallyldimethylammonium chloride and acrylamide, and copolymers of diallylamine hydrochloride and sulfur dioxide can be used.
Examples of inorganic coagulants include known coagulants such as aluminum sulfate, polyaluminum chloride, ferric chloride, polyferric sulfate and slaked lime.
The organic coagulant and the inorganic coagulant may be used alone or in combination of two or more.

In addition, the water treatment agent (P) of the present invention may optionally contain antifoaming agents, chelating agents, pH adjusters, antioxidants, ultraviolet absorbers and preservatives within a range that does not impair the effects of the present invention. One or two or more additives selected from the group consisting of can be used in combination.

Antifoaming agents include silicone oils (eg, dimethylpolysiloxane with Mn of 100 to 100,000), mineral oils (eg, spindle oils and kerosene), and metal soaps having 12 to 22 carbon atoms (eg, calcium stearate). be done.

Chelating agents include aminocarboxylic acids having 6 to 12 carbon atoms (eg, ethylenediaminetetraacetic acid, diethylenetriaminepentaacetic acid, hydroxyethylethylenediaminetriacetic acid, nitrilotriacetic acid and triethylenetetraminehexaacetic acid), polyvalent carboxylic acids [eg, maleic acid, Polyacrylic acid (Mn = 1,000 to 10,000) and isoamylene-maleic acid copolymer (Mn = 1,000 to 10,000)], hydroxycarboxylic acids having 3 to 10 carbon atoms (e.g., citric acid, gluconate acid, lactic acid and malic acid), condensed phosphoric acids (e.g. tripolyphosphoric acid and trimetaphosphoric acid) and salts thereof [e.g. alkali metal (e.g. sodium and potassium) salts, alkaline earth metal (e.g. calcium and magnesium) salts, ammonium salts, C1-C20 alkylamine (eg methylamine, ethylamine and octylamine) salts and C2-C12 alkanolamine (eg mono-, di- or triethanolamine) salts] and the like.

pH adjusters include caustic alkalis (eg caustic soda), amines (eg mono-, di- or triethanolamine), inorganic acids (salts) [eg inorganic acids (eg hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, sulfamic acid and Carbonic acid) and metals [e.g. alkali metals (as above) and alkaline earth metals (as above)] salts (e.g. sodium carbonate, potassium carbonate, sodium sulfate, sodium hydrogen sulfate and monosodium phosphate) and ammonium salts thereof (e.g. ammonium carbonate and ammonium sulfate)], organic acids (salts) [e.g. organic acids (e.g. carboxylic acids, sulfonic acids, phenols) and their metal (same as above) salts (e.g. sodium acetate, sodium lactate) and ammonium salts (eg, ammonium acetate and ammonium lactate)] and the like.

Antioxidants include phenolic 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 [e.g. thiourea, tetramethylthiuram disulfide, dimethyldithiocarbamic acid and its salts [e.g. metal (same as above) salts and ammonium salts], sodium sulfite, sodium bisulfite, sodium thiosulfate, 2- Mercaptobenzothiazole and its salts (same as above), dilauryl 3,3'-thiodipropionate (DLTDP), distearyl 3,3'-thiodipropionate (DSTDP)], phosphorus-containing compounds [e.g. phyte, triethylphosphite, sodium phosphite, sodium hypophosphite, triphenylphosphite (TPP) and triisodecylphosphite (TDP)] and nitrogen-containing compounds [amines (e.g. octylated diphenylamine, Nn- butyl-p-aminophenol and N,N-diisopropyl-p-phenylenediamine), urea, guanidine, the above inorganic acid salts of guanidine] and the like.

UV absorbers include benzophenone compounds (eg 2-hydroxybenzophenone and 2,4-dihydroxybenzophenone), salicylate compounds (eg phenyl salicylate and 2,4-di-t-butylphenyl-3,5-di-t -butyl-4-hydroxybenzoate), benzotriazole compounds [for example (2'-hydroxyphenyl)benzotriazole and (2'-hydroxy-5'-methylphenyl)benzotriazole] and acrylic compounds [for example ethyl-2-cyano- 3,3-diphenyl acrylate and methyl-2-carbomethoxy-3-(paramethoxybenzyl) acrylate] and the like.
Preservatives include, for example, benzoic acid, paraoxybenzoic acid esters and sorbic acid.

The total amount of the additives used is preferably 0 to 40% by weight, more preferably 0 to 20% by weight, based on the total weight of the polymers (A1) and (A2).
The amount of each additive used is preferably 0 to 5% by weight, more preferably 1 to 3% by weight for the antifoaming agent, based on the total weight of the polymers (A1) and (A2), and the chelating agent. is preferably 0 to 30% by weight, more preferably 2 to 10% by weight, pH adjusters are preferably 0 to 10% by weight, more preferably 1 to 5% by weight, antioxidants, UV absorbers and preservatives are Each is preferably 0 to 5% by weight, more preferably 0.1 to 2% by weight.

The water treatment agent (P) of the present invention is used for various industrial wastewater (wastewater from factories such as paper pulp, dyeing, automobiles, metal processing, iron manufacturing, food, gravel extraction, semiconductor-related and cleaning industries), sewage, etc. or factory wastewater By adding it to organic sludge or inorganic sludge generated by such treatments, it is possible to reduce the water-soluble COD reduction effect, improve the clarity of the filtrate (decolorization), reduce the amount of cake generation and cake moisture content. Show effect.

The water treatment method of the present invention is a water treatment method including a step of mixing the water treatment agent (P) with sludge or wastewater, and specifically includes the following methods (1) to (3). be done.
(1) Add and mix (P) to sludge or wastewater, adjust the pH to insolubilize the polymer (A1) and / or (A2) in (P) as necessary, and then solidify the precipitate. A method of liquid separation.
(2) Add and mix (P) to sludge or wastewater, adjust the pH to insolubilize the polymer (A1) and / or (A2) in (P) as necessary, and then further polymer flocculate A method of solid-liquid separation by adding and mixing agents to form coarse flocs.
(3) Add and mix (P) to sludge or wastewater, add and mix an organic coagulant and / or an inorganic coagulant, adjust the pH as necessary, and then add and mix a polymer flocculant. A method of mixing to form coarse flocs for solid-liquid separation.

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

Solid-liquid separation methods include, for example, gravitational sedimentation, membrane filtration, column filtration, pressure flotation, concentration devices (such as thickeners) and dehydration devices (such as centrifugal separators, belt press dehydrators and filter press dehydrators, etc.). ) etc. can be used. If the pH of the sludge or wastewater is low and the polymers (A1) and (A2) in the water treatment agent (P) do not dissolve, the pH of the sludge or wastewater is adjusted before adding the water treatment agent (P). It is preferable to keep

Examples of the organic coagulant and inorganic coagulant in the treatment method (3) include those exemplified as the organic coagulant and inorganic coagulant that may be contained in the water treatment agent (P). It may be used alone or in combination of two or more.
When an organic coagulant or an inorganic coagulant is used, the method of addition is not particularly limited. It may be added pre-mixed.

The polymer flocculant used in the treatment methods (2) and (3) is not particularly limited, and those having an intrinsic viscosity [η] exceeding 0.3 dl/g, which are commonly used as known polymer flocculants, are used. Any of cationic, nonionic, anionic and amphoteric can be used, and these can also be used in combination.

Examples of cationic polymer flocculants include polyethylenimine, Mannich-modified poly(meth)acrylamide, homopolymers of dialkylaminoethyl (meth)acrylate quaternaries, and other monomers such as (meth)acrylamide. Examples thereof include copolymers and (co)polymers containing other cationic monomers as constitutional units.

Examples of nonionic polymer flocculants include polyacrylamide.
Examples of anionic polymer flocculants include sodium poly(meth)acrylate, hydrolyzate of poly(meth)acrylamide, (meth)acrylamide/sodium (meth)acrylate copolymer, (meth)acrylamide/(meth) Sodium acrylate/sodium 2-acrylamide-2-methylpropane-1-sulfonate copolymer, (meth)acrylamide/sodium 2-acrylamido-2-methylpropane-1-sulfonate copolymer and other anionic Examples thereof include (co)polymers containing the monomer (a).

Amphoteric polymer flocculants include cationic monomers (dialkylaminoethyl (meth)acrylate quaternary products, etc.) and anionic monomers [(meth)acrylic acid (salt), 2-acrylamido-2-methylpropane-1-sulfone acids (salts) and other anionic monomers (a), etc. above] and, if necessary, copolymers with nonionic monomers (acrylamide, etc.).

Among these, cationic polymer flocculants and amphoteric polymer flocculants are preferred from the viewpoint of neutralizing the charge with the polymer and promoting precipitation.
When the organic coagulant or inorganic coagulant used in combination is added in an amount exceeding the charge equivalent of (P), an anionic polymer flocculant and an amphoteric polymer flocculant are preferred.

As a measure of the molecular weight of the polymer flocculant, the intrinsic viscosity measured at 30° C. in a 1N—NaNO ₃ aqueous solution can be used in the same manner as the intrinsic viscosities of the polymers (A1) and (A2). The intrinsic viscosity of the cationic polymer flocculant is preferably 4 to 30 dl/g, more preferably 5 to 20 dl/g, from the viewpoint of flocculation performance (floc particle size and floc strength). From the same viewpoint, the intrinsic viscosity is preferably 5 to 40 dl/g, more preferably 8 to 30 dl/g. From the same viewpoint, the intrinsic viscosity of the anionic polymer flocculant is preferably 5 to 40 dl/g. More preferably 6 to 30 dl/g.

The pH of the sludge or wastewater when adding the water treatment agent (P) is preferably 4.5 or higher from the viewpoint of hydrophilicity of the polymers (A1) and/or (A2) in (P). After adding and stirring (P), adjust the pH to 4.5 or less, or neutralize the charge of the polymer (A1) and / or (A2) in (P) to make (P) hydrophobic. The effects of the present invention, such as water-soluble COD reduction, can be exhibited more effectively. That is, (P) hydrated by the anionic group is hydrophobized by the above action, and the complex of the polymer (A1) and/or (A2) and the water-soluble COD component can be insolubilized.

As a method of adding the water treatment agent (P) to sludge or wastewater, when (P) is an aqueous solution or dispersion, it is added as it is or diluted with water to the sludge or wastewater and stirred sufficiently. However, if (P) does not contain water, it may be used as an aqueous solution or added directly to the sludge or wastewater. When (P) is used as an aqueous solution, the concentration of the polymers (A1) and (A2) (the total concentration when used in combination) is preferably 0.01 to 20% by weight, more preferably 0.1 to 5% by weight. %.
The dissolution method of (P) and the dilution method after dissolution are not particularly limited, but for example, a predetermined amount of polymer (A1) and / or ( A2) can be added and dissolved by stirring for several hours (about 1 to 4 hours).

The amount of water treatment agent (P) used varies depending on the type of sludge or wastewater, the content of suspended particles, the amount of water-soluble COD components, etc., and is not particularly limited, but from the viewpoint of water-soluble COD reduction performance , The amount of polymer (A1) and / or (A2) used (total amount when used in combination) is based on the weight of wastewater and sludge, preferably 0.0001 to 1% by weight, more preferably is 0.0003 to 0.8% by weight, particularly preferably 0.0005 to 0.5% by weight, most preferably 0.0005 to 0.3% by weight.

In the water treatment method of the present invention, when an inorganic coagulant and/or an organic coagulant is added to the wastewater, the amount used depends on the type of sludge or wastewater, the size of suspended particles, and the total sludge and sludge in the wastewater. The amount of the inorganic coagulant used is preferably 0.001 to 1 wt%, more preferably 0.005 to 0.8 wt%, more preferably 0.005 to 0.8 wt%, and particularly It is preferably 0.01 to 0.5% by weight. If it is 0.001% by weight or more, the water-soluble COD reduction performance is good, and if it is 1% by weight or less, the amount of sludge generated can be reduced. In addition, 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 water-soluble COD reduction performance. , particularly preferably 0.0005 to 0.1% by weight.

In the above treatment methods (2) and (3), the method of adding the polymer flocculant to the sludge or wastewater after treatment with the water treatment agent of the present invention is not particularly limited, and the polymer flocculant can be added as it is. However, from the viewpoint of uniform mixing, a method of making the polymer flocculant into an aqueous solution and then adding it to the sludge or wastewater is preferable. 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 can be carried out in the same manner as in the case of the water treatment agent (P). When dissolving a powdery polymer flocculant in water, it is not preferable to add the polymer flocculant all at once because lumps are formed and the solution becomes difficult to dissolve in water.

In the above treatment methods (2) and (3), the amount of polymer flocculant used when added to sludge or wastewater depends on the type of sludge or wastewater, the content of suspended particles, and the molecular weight of the polymer flocculant. etc., but from the viewpoint of flocculation performance, preferably 0.0001 to 0.5 wt%, more preferably 0.0002 to 0.3 wt%, particularly preferably 0.0003, based on the weight of sludge or wastewater ~0.2 wt%, most preferably 0.0004-0.1 wt%.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples. In addition, the part in an Example represents a weight part.

COD in the examples was measured according to the COD _Mn analysis method described in JIS K0102:2016.
In Examples 10 to 18 and Comparative Examples 4 to 7 below, TOC (total organic carbon), which is commonly used as an alternative means of monitoring COD in the field of wastewater treatment and can be easily measured from COD, is also shown. . TOC was measured using multi N/C 3100 manufactured by Analytique Jena Japan.

Regarding the solubility of the polymer (A1) or (A2) in the water treatment agent (P) in water of pH 5.0, 100 g of water at 20°C adjusted to pH 5.0 using hydrochloric acid was taken in a 200 ml beaker, Add 5 g of (P), stir with a magnetic stirrer at room temperature (20° C.) for 1 hour, filter with a G3 glass filter, and dry the filtrate at 130° C. for 90 minutes. was 1% by weight or more.

Compositions, symbols, etc. of raw materials used in the examples are as follows.
(1) anionic monomer (a)
(a-1): methacrylic acid (a-2): 2-acrylamido-2-methylpropanesulfonic acid (2) nonionic monomer (b)
(b-1): Lauroxy polyethylene glycol methacrylate (Polyethylene glycol has a degree of polymerization of 30 and a solubility in water at 20° C. of 1 g or more/100 g of water) (manufactured by NOF Corporation: PLE-1300)
(b-2): Stealoxy polyethylene glycol methacrylate (polymerization degree of polyethylene glycol is 30, solubility in water at 20° C. is 1 g or more/100 g of water) (manufactured by NOF Corporation: PSE-1300)
(b-3): Lauroxy polyethylene glycol methacrylate (Polyethylene glycol has a degree of polymerization of 4, solubility in water at 20° C. is 1 g or more/100 g of water) (manufactured by NOF Corporation: PLE-200)
(rb-1): 2-ethylhexyl-diglucol acrylate (polymerization degree of polyethylene glycol is 2, solubility in water at 20°C is 1 g or more/100 g of water) (manufactured by Kyoeisha Chemical Co., Ltd.: EHDG-AT)
(rb-2): Methoxy polyethylene glycol methacrylate (polymerization degree of polyethylene glycol is 9, solubility in water at 20° C. is 1 g or more/100 g of water) (manufactured by NOF Corporation: PME-400)
(rb-3): Methoxy polyethylene glycol methacrylate (Polyethylene glycol has a degree of polymerization of 4, solubility in water at 20° C. is 1 g or more/100 g of water) (manufactured by NOF Corporation: PME-400)
The solubility of the nonionic monomer (b) in water at 20° C. was determined by allowing a mixture of 100 g of ion-exchanged water at 20° C. and 1 g of the nonionic monomer (b) to stand still for 24 hours, and turning the water layer into a high-speed liquid. It was confirmed by analyzing with a chromatograph or the like, quantifying the amount of the monomer in the aqueous layer, and calculating the concentration of the monomer in the aqueous solution.
(4) Polymer flocculant (F-1): Sunflock CDS-019 [Sanyo Chemical Industries, Ltd. cationic polymer flocculant]

<Example 1>
190 parts of isopropyl alcohol (hereinafter abbreviated as "IPA") and 68 parts of ion-exchanged water are added to a four-necked flask equipped with a stirrer, temperature sensor, condenser, dropping funnel and mantle heater, and heated to reflux while stirring. let me A mixed solution of 80 parts of IPA as an initiator solution from the dropping port, 20 parts of ion-exchanged water and 2.0 parts of azobisisobutyronitrile (hereinafter abbreviated as “AIBN”) is added from the other dropping port as a monomer solution. 220 parts of anionic monomer (a-1), 180 parts of nonionic monomer (b-1), 180 parts of IPA and 60 parts of ion-exchanged water were stirred in the flask at 80 to 85°C for 4 hours each. were dropped into the flask at the same time. After completion of the dropwise addition, aging at the same temperature for 2 hours, 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 over 1 hour and aged at the same temperature for 180 minutes. did. After that, 1000 parts of ion-exchanged water was charged into the flask, and 213 parts of a 48% by weight sodium hydroxide aqueous solution was added dropwise over 1 hour. Subsequently, the temperature was raised to 100° C. to remove IPA to obtain 1755 parts of a water treatment agent (P-1) containing the polymer (A1-1). The solid content concentration of (P-1) was 26.2% by weight, the pH was 7.2, and the intrinsic viscosity [η] of the polymer (A1-1) in (P-1) was 0.38 dl/g. rice field.

<Examples 2 to 9>
[Production of water treatment agents (P-2) to (P-9)]
Each water treatment agent was obtained in the same manner as in Example 1 except that the types and amounts of raw materials used were changed to those shown in Table 1. Table 1 shows the analytical values of each water treatment agent.

<Comparative Examples 1 to 3>
[Production of water treatment agents (RP-1) to (RP-3)]
Each water treatment agent was obtained in the same manner as in Example 1 except that the types and amounts of raw materials used were changed to those shown in Table 1. Table 1 shows the analytical values of each water treatment agent.

<Examples 10 to 18 and Comparative Examples 4 to 7>
As a nonionic surfactant, a mixture of polyoxyethylene oleyl ether and polyoxyethylene cetyl ether "Emalmin 140, manufactured by Sanyo Chemical Industries Co., Ltd." was dissolved in tap water to a concentration of 100 mg/L. This target water had a COD of 98 ppm and a TOC of 75 ppm.
The water treatment agents (P-1) to (P-9) and (RP-1) to (RP-3) used in each example were diluted with tap water in advance so that the solid content concentration was 5% by weight. I left it.
500 mL of the target water is collected in a beaker, and under stirring, an aqueous solution of (P-1) to (P-9) or (RP-1) to (RP-3) with a solid content concentration of 5% in the target water (P ) was added so that the concentration of the polymer (A1) or (A2) in ) was the value described in the column of the amount of addition of the water treatment agent (P) in Table 2, and the mixture was stirred for 3 minutes. Subsequently, aluminum sulfate (8% by weight aqueous solution) as an inorganic coagulant was added in an amount shown in Table 2, stirred for 3 minutes, and then adjusted to pH 6.5 to 7 with an aqueous sodium hydroxide solution. 0.5. Subsequently, while stirring was continued, a 0.2% by weight aqueous solution of Sunflock CDS-019 (F-1) as a polymer flocculant was added so that the solid content concentration was 10 ppm, and the mixture was stirred for 3 minutes. The supernatant liquid was filtered with filter paper (No. 5C), and the COD and TOC of the filtrate were measured.
Examples 10 to 18 and Comparative Examples 4 to 6 were obtained using (P-1) to (P-9) or (RP-1) to (RP-3) as water treatment agents. In Comparative Example 7, the same operation was performed using only aluminum sulfate and polymer flocculant (F-1).
From the obtained COD and TOC values, the COD removal rate and TOC removal rate were calculated based on the following formulas, and the removal performance of the nonionic surfactant was evaluated. Table 2 shows the results.
COD removal rate = (COD value before treatment - COD value after treatment) / COD value before treatment x 100
TOC removal rate=(TOC value before treatment−TOC value after treatment)/TOC value before treatment×100

<Examples 19 to 27 and Comparative Examples 8 to 10>
The water to be treated was replaced with chemical factory wastewater with a COD of 220 ppm containing a nonionic surfactant, and the amount of the chemical used was changed to the amount shown in Table 3. The COD removal rate was calculated from the COD value, and the COD reduction performance was evaluated. Table 3 shows the results.

<Examples 28 to 36 and Comparative Examples 11 to 13>
The same operation as in Example 1 was performed except that the water to be treated was replaced with waste water from a dyeing factory with a COD of 1100 ppm containing polyvinyl alcohol, and the amount of the chemical used was changed to the amount shown in Table 4. From the COD value obtained , the COD removal rate was calculated, and the COD reduction performance was evaluated. Table 4 shows the results.

From the results in Tables 2 to 4, it can be seen that the water treatment agent (P) of the present invention is superior to the comparative agent in removing water-soluble COD components.

Since the water treatment agent of the present invention exhibits a higher effect of removing water-soluble COD components than conventional ones, it can be used as a treatment agent for wastewater containing organic components such as sewage or industrial wastewater. can.
In addition, other applications include, for example, muddy water treatment at civil engineering sites, treatment agents for promoting sedimentation and separation of muddy water during dredging and reclamation, soil modifiers for generated soil, paper manufacturing agents (e.g. formation aids for paper manufacturing industry) agents, drainage retention improvers, drainage improvers and paper strength agents), additives for increasing crude oil production (additives for secondary and tertiary recovery of crude oil), dispersants, scale inhibitors, coagulants, decolorants, Thickeners, antistatic agents and fiber treatment agents are mentioned, and among these, muddy water treatment at civil engineering sites, treatment agents for promoting sedimentation and separation of muddy water at the time of dredging and reclamation, soil modifiers for generated soil and It is particularly suitable for use as a papermaking agent.

Claims (5)

Polymer (A1) containing as constituent monomers anionic monomer (a) represented by general formula (1) and nonionic monomer (b) represented by general formula (2) and/or general formula A water treatment agent (P) containing a polymer (A2) having only the nonionic monomer (b) represented by (2) as a constituent monomer.

_CH2 =CR1 ^- X ^- .Y ⁺ (1)

[wherein R ¹ is a hydrogen atom or a methyl group, X ^- is COO ^- , SO ₃ ^- , C ₆ H ₄ SO ₃ ^- or CONHC(CH ₃ ) ₂ CH ₂ SO ₃ ^- , and Y ⁺ is It is a monovalent cation. ]

_CH2 =CR2 ^{- COO-} ( _C2H4O ) _n -R3 ( ₂ )

[In the formula, R ² is a hydrogen atom or a methyl group, R ³ is an alkyl group having m carbon atoms, m is an integer of 8 to 30, and n is the value of n/m to the second decimal place. It is a number that gives a value of 0.3 to 2.5 when rounded off by . ] The water treatment agent according to claim 1, wherein the polymers (A1) and (A2) have an intrinsic viscosity [η] of 0.010 to 3.0 dl/g. 3. The weight ratio [(a):(b)] of the anionic monomer (a) and the nonionic monomer (b) in the polymer (A1) is 10:90 to 98:2 according to claim 1 or 2. of water treatment agents. The water treatment agent according to any one of claims 1 to 3, wherein the solubility of the polymers (A1) and (A2) in water at pH 5.0 and 25°C is 1 g or more/100 g of water. A water treatment method comprising the step of mixing the water treatment agent according to any one of claims 1 to 4 with sludge or wastewater.