JP2011062634A - Flocculant for service water and method for treating raw water for service water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flocculant for service water which is invented after studying whether an organic polymer flocculant is applied to flocculation treatment of raw water for service water, which has not the same risk of inducing Alzheimer's disease as PAC (poly aluminum chloride) and which has the flocculation power more excellent than that of a starch-based or cellulose-based flocculant. <P>SOLUTION: The flocculant for service water includes a water-soluble polymer having 35-90% charge inclusion rate to be represented by a definition. The water-soluble polymer is obtained by polymerizing a monomer mixture containing a specific monomer and a cross-linkable monomer essentially. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a flocculating agent for clean water, and more specifically, is a flocculating agent for clean water composed of a water-soluble polymer having a charge inclusion rate of 35% or more and 90% or less, which is represented by a definition. The present invention relates to a water-soluble polymer obtained by polymerizing a monomer mixture containing a specific monomer and a crosslinkable monomer as essential components. Moreover, it is related with the processing method of the raw water for water supplies using the said water-soluble polymer.

The raw water treated for drinking is subjected to flocculation treatment to remove suspended matter and dissolved organic matter in the raw water. Flocculants used for water treatment include aluminum sulfate and polyaluminum chloride, but these inorganic flocculants do not form sufficiently large flocs when used alone, so solid-liquid separation in the coagulation sedimentation step and sand filtration step The speed is small. In recent years, eutrophication of raw water for drinking water has progressed, and in raw water containing a large amount of algae such as microcystis, only floc with extremely poor sedimentation is formed in the PAC or sulfate band, and the floc may rise. There is also a major problem that it is impossible to remove algae effectively. In addition, there is a disadvantage that the sludge discharged from the coagulation separation process has poor sedimentation concentration and dewatering properties. Although titanyl sulfate has been proposed as an improvement of the inorganic flocculant, it is not widespread due to cost problems (Patent Document 1).

To solve these drawbacks, the use of synthetic organic polymer flocculants such as polyacrylamide can be considered to promote floc formation. Due to the toxicity of monomers such as acrylamide contained in the polymer flocculant, its use is not officially approved for water treatment in Japan. As a natural polymer flocculant having no safety problem, sodium alginate or carboxymethyl cellulose (Patent Document 2) is less costly for floc formation than synthetic organic polymer flocculants such as polyacrylamide. It is not used for water treatment.

Conventionally, (1) organic solvent cleaning method, (2) reprecipitation method, and (3) radiation irradiation method have been proposed as the monomer removal technology in the polymer flocculant. It takes a long time to dissolve in the solvent, and there is a problem in the detoxification treatment of the dissolved monomer. The reprecipitation method is a method in which a polymer is dissolved in water and then a large amount of methanol is added to reprecipitate the polymer and the monomer is dissolved in methanol. However, this method requires a large amount of an organic solvent and still has a problem in the processing of the monomer. The radiation irradiation method is a method of polymerizing monomers remaining in the polymer by irradiating the polymer with radiation such as gamma rays. However, radiation reduces the monomer, but at the same time, the polymer chain breaks and the agglomeration effect worsens, and the polymer cross-linking reaction occurs in parallel, resulting in gelation and insoluble particles. There's a problem.
JP-A-9-168786 JP 2004-113892 A

The object of the present invention is to examine the application of an organic polymer flocculant to the flocculation treatment of raw water for clean water, there is no risk of Alzheimer's disease such as PAC, there are few residual monomers, and starch-based or cellulose-based It is to provide a flocculant for clean water having a superior cohesive strength as compared with the above.

As a result of intensive studies in order to solve the above problems, the present inventor has reached the invention as described below. The invention of claim 1 is a water-soluble polymer having a charge inclusion rate of 35% or more and 90% or less represented by the following definition, wherein the water-soluble polymer is a monomer represented by the following general formula (1) And a water-flocculating agent comprising a water-soluble polymer obtained by polymerizing a monomer mixture containing a crosslinkable monomer as an essential component.
Definition 1) Charge in the case of a cationic cross-linkable water-soluble ionic polymer and a cross-linkable water-soluble ionic polymer that is amphoteric and has a positive molar concentration difference between a cationic monomer and an anionic monomer Inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a cross-linkable water-soluble ionic polymer aqueous solution adjusted to pH 4.0 with acetic acid with an aqueous potassium polyvinyl sulfonate solution. β is added to a crosslinkable water-soluble ionic polymer aqueous solution adjusted to pH 4.0 with acetic acid in an amount sufficient to neutralize the charge of the crosslinkable water-soluble ionic polymer, and then Titration volume obtained by subtracting the titration titrated with polydiallyldimethylammonium chloride aqueous solution from the blank value (blank value: potassium poly (vinyl sulfonate) aqueous solution with polydiallyldimethylammonium chloride aqueous solution when no crosslinkable water-soluble ionic polymer aqueous solution was added Titration titration).
Definition 2) Charge in the case of an anionic crosslinkable water-soluble ionic polymer and a crosslinkable water-soluble ionic polymer that is amphoteric and has a negative difference in molar concentration between the cationic monomer and the anionic monomer Inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a cross-linkable water-soluble ionic polymer aqueous solution adjusted to pH 10.0 with ammonia with a polydiallyldimethylammonium chloride aqueous solution. β is added to a crosslinkable water-soluble ionic polymer aqueous solution adjusted to pH 10.0 with ammonia in an amount sufficient to neutralize the charge of the crosslinkable water-soluble ionic polymer with a polydiallyldimethylammonium chloride aqueous solution, Titrate after titration with potassium polyvinylsulfonate aqueous solution was subtracted from the blank value (blank value: diallyldimethylammonium chloride aqueous solution titrated with potassium polyvinylsulfonate aqueous solution when no crosslinkable water-soluble ionic polymer aqueous solution was added. Titration).
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl group having 1 to ₃ carbon atoms, an alkoxy group or a benzyl group, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group. , Same or different. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.

The invention according to claim 2 is characterized in that the water-soluble polymer comprises a mixture aqueous solution containing the monomer represented by the general formula (1) and a crosslinkable monomer as a disperse phase, and is immiscible with water. The water-in-oil emulsion obtained by emulsifying and polymerizing a liquid with a surfactant so as to form a continuous phase, and then drying the resulting water-soluble polymer powder. It is a flocculant.

The invention of claim 3 is characterized in that the copolymerization rate of the monomer represented by the general formula (1) constituting the water-soluble polymer is 20 to 95 mol%. The flocculant for clean water described in 1.

In the invention of claim 4, when the water-soluble polymer is amphoteric, when the water-soluble amphoteric polymer is dissolved in 0.1% by mass or more, an acidic substance in an amount that makes the solution pH 4 or less is mixed. It is a flocculant for clean water in any one of Claims 1-3 characterized by the above-mentioned.

The invention of claim 5 is a flocculant for water supply comprising a water-soluble polymer having a charge inclusion ratio of 35% or more and 90% or less represented by the following definition when separating suspended matter in raw water for water supply. The water-soluble polymer is a water-soluble polymer obtained by polymerizing a monomer mixture containing the monomer represented by the following general formula (1) and a crosslinkable monomer as essential components. This is a method for treating raw water for water supply.
Definition 1) Charge in the case of a cationic cross-linkable water-soluble ionic polymer and a cross-linkable water-soluble ionic polymer that is amphoteric and has a positive molar concentration difference between a cationic monomer and an anionic monomer Inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a cross-linkable water-soluble ionic polymer aqueous solution adjusted to pH 4.0 with acetic acid with an aqueous potassium polyvinyl sulfonate solution. β is added to a crosslinkable water-soluble ionic polymer aqueous solution adjusted to pH 4.0 with acetic acid in an amount sufficient to neutralize the charge of the crosslinkable water-soluble ionic polymer, and then Titration volume obtained by subtracting the titration titrated with polydiallyldimethylammonium chloride aqueous solution from the blank value (blank value: Polyvinyl dimethylammonium chloride aqueous solution with polydiallyldimethylammonium chloride aqueous solution when no crosslinkable water-soluble ionic polymer aqueous solution was added) Titration titration).
Definition 2) Charge in the case of an anionic crosslinkable water-soluble ionic polymer and a crosslinkable water-soluble ionic polymer that is amphoteric and has a negative difference in molar concentration between the cationic monomer and the anionic monomer Inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a cross-linkable water-soluble ionic polymer aqueous solution adjusted to pH 10.0 with ammonia with a polydiallyldimethylammonium chloride aqueous solution. β is added to a crosslinkable water-soluble ionic polymer aqueous solution adjusted to pH 10.0 with ammonia in an amount sufficient to neutralize the charge of the crosslinkable water-soluble ionic polymer with a polydiallyldimethylammonium chloride aqueous solution, Titrate after titration with potassium polyvinylsulfonate aqueous solution was subtracted from blank value (blank value: diallyldimethylammonium chloride aqueous solution was titrated with potassium polyvinylsulfonate aqueous solution when no crosslinkable water-soluble ionic polymer aqueous solution was added. Titration).
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl group having 1 to ₃ carbon atoms, an alkoxy group or a benzyl group, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group. , Same or different. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.

The present invention relates to PAC, titanium flocculant, polydiallylammonium salt and acrylamide low molecular weight copolymer, anionic polyacrylamide copolymer, which are inorganic aluminum flocculants conventionally used for raw water for drinking water. Instead, a water-soluble polymer having a charge inclusion rate of 35% or more and 90% or less is used. The following can be considered as this reason. That is, the linear water-soluble polymer exists in a state where the molecules are spread in water. It is considered that the aggregating action of a high-molecular weight cationic water-soluble polymer such as a polymerization system is caused by a binding action of a large number of suspended particles by a so-called “cross-linking adsorption action” by a molecular chain of the water-soluble polymer. In general, raw water for drinking water contains dissolved or dispersed organic substances such as humic substances or soluble COD components in addition to inorganic suspended particles such as mud and sand. However, humic substances and the like are small molecules, and are present in water as stable colloids that are charged anionic. For this reason, the surface charge is neutralized by PAC or the like to generate fine flocs. On the other hand, polydiallylammonium salts and acrylamide low molecular weight copolymers can remove organic substances such as humic substances by adsorption, but titanium-based flocculants and anionic polyacrylamide copolymers are inorganic suspensions. Organic substances cannot be removed even if they have particle agglomeration and precipitation effects.

On the other hand, the crosslinkable water-soluble polymer suppresses the spread of molecules in water by crosslinking. For this reason, it exists as a “density packed” molecular form, and when the crosslinking proceeds further, it becomes a water-swellable fine particle. It is considered efficient that the above-mentioned “density-packed” molecular form is usually used as a polymer flocculant. When a crosslinkable water-soluble polymer is added to raw water for drinking water, unlike the linear water-soluble polymer, no huge floc is generated due to cross-linking adsorption. Similar to the polymer, functions such as neutralization of surface charge are expressed and fine flocs are generated. That is, it reacts with organic colloids such as humic substances to produce fine flocs. On the other hand, since the molecular form is larger than PAC, titanium-based flocculant, polyamine-based polycondensation polymer or polydiallylammonium salt and acrylamide low molecular weight copolymer, inorganic suspended particles such as mud and sand can be efficiently removed. . That is, it is considered that water-soluble polymers have more particulate properties as the degree of crosslinking increases. The water-soluble polymer having a high degree of crosslinking used in the present invention is considered to have an intermediate property between water-insoluble particles having undergone crosslinking and a linear water-soluble polymer.

The water-soluble polymer having a high degree of cross-linking used in the present invention can reduce the risk of Alzheimer's disease compared to PAC which is a conventionally used inorganic aluminum-based flocculant, and also includes a titanium-based flocculant or an anionic polyacrylamide copolymer. Compared with products, not only organic substances such as humic substances can be removed, but also residual monomers are reduced in the course of drying the water-in-oil emulsion, and inorganic suspended particles such as mud and sand can be efficiently removed.

First, the cationic water-soluble polymer (A) having a charge inclusion rate of 35% or more and 90% or less will be described. The charge inclusion rate is defined as follows. That is, in the case of a water-soluble cationic polymer and a water-soluble polymer that is amphoteric and has a positive difference in the copolymerization rate between a cationic monomer and an anionic monomer, the charge inclusion rate [%] = (1-α / β) × 100
α is a titration amount obtained by titrating a water-soluble cationic polymer or an amphoteric water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid with a potassium polyvinyl sulfonate aqueous solution. β is a water-soluble cationic polymer or an amphoteric water-soluble polymer aqueous solution adjusted to pH 4.0 with acetic acid, and an aqueous polyvinyl sulfonate potassium solution is used to neutralize the charge of the water-soluble cationic polymer or amphoteric water-soluble polymer. A titration amount obtained by adding a sufficient amount to perform, and then subtracting the titration amount titrated with an aqueous polydiallyldimethylammonium chloride solution from the blank value. Here, the blank value is a titration amount obtained by titrating a potassium polyvinylsulfonate aqueous solution with a polydiallyldimethylammonium chloride aqueous solution when no water-soluble cationic polymer or amphoteric water-soluble polymer aqueous solution was added.

That is, it can be said that a water-soluble polymer having a high charge encapsulation rate is a water-soluble polymer with increased crosslinking, and a water-soluble polymer having a low charge encapsulation rate is a water-soluble polymer having little crosslinking. The reason for this is explained as follows. A linear water-soluble polymer has a substantially “stretched” shape in a dilute solution. On the other hand, the crosslinkable water-soluble polymer has a rounded particle shape in the solution, and the ionic group present inside the particle is unlikely to appear on the outside and reacts slowly with the opposite charge. It is thought to happen.

Hereinafter, the meaning of α and β in the above formula will be briefly described. In the above formula, the titration amount α is obtained by dropping a potassium polyvinyl sulfonate aqueous solution having an opposite charge onto a crosslinkable cationic (amphoteric) water-soluble polymer as a sample, and then “surface” of the water-soluble cationic (amphoteric) polymer. ”Means an operation of causing an ionic electrostatic reaction to occur on the ionic group present on the (particulate surface portion).

Thereafter, potassium polyvinyl sulfonate having an opposite charge more than an amount sufficient to neutralize the theoretical charge amount of the crosslinkable cationic (amphoteric) water-soluble polymer was added, the reaction time was sufficient, and then the surplus Of polyvinyl sulfonate is titrated with an aqueous diallyldimethylammonium chloride solution. Separately, titrate the potassium polyvinyl sulfonate solution with diallyldimethylammonium chloride aqueous solution without adding a crosslinkable cationic (amphoteric) water-soluble polymer, and give a blank value. This value is β after subtracting the titration amount when the functional polymer is added. The β value is considered to correspond to the theoretical charge calculated from the chemical composition of the crosslinkable cationic (amphoteric) water-soluble polymer. In other words, the cross-linkable cationic (amphoteric) water-soluble polymer has a large amount of opposite charge, so it is considered that not only the surface cationic charge but also the internal charge is electrostatically neutralized. . If the degree of crosslinking is high, α is smaller than β, and the (1-α / β) value is larger than 1 and the charge inclusion rate is large (that is, the degree of crosslinking is high).

In the present invention, in order to produce a water-soluble cationic polymer or a water-soluble amphoteric polymer having the charge inclusion rate as described above, a crosslinkable monomer as a polymer structure modifier is 0% of the total amount of monomers. .0005 to 0.0050 mol%, preferably 0.001 to 0.003 mol%, is present during or after polymerization. Examples of the crosslinkable monomer include N, N-methylenebis (meth) acrylamide, triallylamine, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and dimethacrylic acid. Acid-1,3-butylene glycol, polyethylene glycol di (meth) acrylate, N-vinyl (meth) acrylamide, N-methylallylacrylamide, glycidyl acrylate, polyethylene glycol diglycidyl ether, acrolein, glyoxal, vinyltrimethoxysilane In this case, the crosslinking agent is more preferably a water-soluble polyvinyl compound, and most preferably N, N-methylenebis (meth) acrylamide. Use of a chain transfer agent such as sodium formate or isopropyl alcohol in combination is also effective as a method for adjusting the crosslinkability.

In the case of producing a water-soluble amphoteric polymer, the desired product can be obtained by the same operation except that an anionic monomer is allowed to coexist during polymerization. The crosslinkable monomer used is the same as described above, and most preferred is N, N-methylenebis (meth) acrylamide. It is effective to use a chain transfer agent in combination.

The cationic monomer used for producing the water-soluble cationic polymer is obtained by polymerizing a monomer or a monomer mixture containing the monomer represented by the general formula (1) as an essential component. . The water-soluble amphoteric polymer is obtained by polymerizing a monomer mixture containing the monomer represented by the general formula (1) and the monomer represented by the general formula (2) as essential components. Examples of cationic monomers are (meth) acryloyloxyalkyl quaternary ammonium salts, (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, (meth) acryloyloxy-2-hydroxy Examples of the (meth) acryloyloxyalkyl tertiary amine salt such as propyltrimethylammonium bromide include (meth) acryloyloxyethyldimethylamine sulfate and (meth) acryloyloxypropyldimethylamine hydrochloride. Examples of (meth) acryloylaminoalkyl quaternary ammonium salts include (meth) acryloylaminopropyltrimethylammonium chloride and (meth) acryloylaminopropyltrimethylammonium methyl sulfate. Examples of the (meth) acryloylamino (hydroxy) alkyl tertiary amine salt include (meth) acryloylaminoethyldimethylamine hydrochloride and sulfate.

Examples of anionic monomers used to produce water-soluble amphoteric polymers are vinyl sulfonic acid, vinyl benzene sulfonic acid or 2-acrylamide 2-methylpropane sulfonic acid, methacrylic acid, acrylic acid, itaconic acid, maleic acid Or p-carboxystyrene.

In the case of producing a water-soluble cationic polymer or a water-soluble amphoteric polymer, a nonionic monomer may be copolymerized, and examples thereof include the following. That is, acrylamide, N, N-dimethylacrylamide, vinyl acetate, acrylonitrile, methyl acrylate, 2-hydroxyethyl (meth) acrylate, diacetone acrylamide, N-vinylpyrrolidone, N-vinylformamide, N-vinylacetamide, acryloylmorpholine Etc.

The mol% of the cationic monomer in these water-soluble polymers is 20 to 95 mol%, preferably 30 to 95 mol%. For this reason, if the cationic monomer is lower than 20 mol%, the cohesive force and the adsorption ability of organic substances are lowered. Further, it is preferable to copolymerize a nonionic monomer such as acrylamide because crosslinking is easily involved. Therefore, the molar% of the cationic monomer is 95 mol% at the maximum. An amphoteric water-soluble polymer can also be used. In that case, the anionic monomer has a mol% of 2 to 30 mol%, preferably 5 to 20 mol%. The molecular weight is 1 million to 2 million in weight average molecular weight, preferably 2 million to 10 million.

The product form of the water-soluble cationic polymer or the water-soluble amphoteric polymer in the present invention can be implemented in any form such as a powder or a dispersion in an aqueous salt solution.

The powdered product can be manufactured as follows. For example, a dispersion obtained by dispersion polymerization in an aqueous salt solution or water immiscible organic liquid or a water-in-oil emulsion is obtained, and then dried and granulated powder. That is, in the case of a dispersion polymerized by dispersion in salt water, there is a method of directly putting it in a dryer and drying it for a certain period of time to pulverize the sheet. In the case of a dispersion obtained by dispersion polymerization in water in an immiscible organic liquid, the immiscible organic liquid is separated, and wet polymer particles are dried in a dryer to form a powder. The water-in-oil emulsion may be spray-dried or may be directly put into a dryer and dried for a predetermined time to pulverize the sheet.

In the case of a water-in-oil emulsion, an ionic monomer, or an ionic monomer, a monomer that can be copolymerized, and a molar ratio that maintains a water-soluble polymer formed with these monomers are added. A monomer mixture containing a crosslinkable monomer is water, an oily substance comprising at least water-immiscible hydrocarbons, an amount effective to form a water-in-oil emulsion and at least one interface having an HLB It is synthesized by mixing the activator, stirring vigorously to form a water-in-oil emulsion and polymerizing.

Examples of oily substances composed of hydrocarbons used as dispersion media include paraffins, mineral oils such as kerosene, light oil, and middle oil, or hydrocarbon-based synthetics having characteristics such as boiling point and viscosity substantially in the same range as these. An oil or a mixture thereof may be mentioned. As content, it is the range of 20 mass%-50 mass% with respect to the water-in-oil type emulsion whole quantity, Preferably it is the range of 20 mass%-35 mass%.

Examples of at least one surfactant having an amount effective to form a water-in-oil emulsion and HLB are HLB 1-8 nonionic surfactants, specific examples of which include sorbitan monooleate Sorbitan monostearate, sorbitan monopalmitate and the like. The addition amount of these surfactants is 0.5 to 10% by mass, preferably 1 to 5% by mass, based on the total amount of the water-in-oil emulsion.

In this case, the emulsion emulsified with a high HLB surfactant to form a water-in-oil emulsion and polymerized is compatible with water as it is, so there is no need to add a phase inversion agent. These surfactants have an HLB of 9-20, preferably 11-11.
20 things are used. Examples of such surfactants are cationic surfactants and HLB 9-15 nonionic surfactants, such as polyoxyethylene polyoxypropylene alkyl ether systems, polyoxyethylene alcohol ether systems, and the like It is.

When emulsified and polymerized with a low-HLB surfactant, a hydrophilic interfacial modifier called a phase inversion agent is added after the polymerization to make the emulsion particles covered with the oil film easy to adapt to water, The molecule is treated so that it is easily dissolved, diluted with water and used for each application. Examples of hydrophilic surfactants are cationic surfactants and nonionic surfactants of HLB 9-15, such as polyoxyethylene polyoxypropylene alkyl ether systems and polyoxyethylene alcohol ether systems. is there.

In the case of a dispersion in an aqueous salt solution, an aqueous solution of a polyvalent anion salt such as ammonium sulfate is prepared and charged with a mixture of a cationic monomer or a nonionic monomer. In the case of a polymer, an anionic monomer can be squeezed, and a polymer dispersant soluble in the aqueous salt solution can be used as a dispersant in the presence of stirring to carry out dispersion polymerization and synthesis.

As the polymer dispersant, either a nonionic or cationic polymer can be used, but a cationic polymer is more preferable. Cationic polymers include acrylic cationic monomers such as inorganic acid and organic acid salts such as dimethylaminoethyl (meth) acrylate and dimethylaminopropyl (meth) acrylamide, or methyl chloride and benzyl chloride. It is a copolymer of quaternary ammonium salt and acrylamide. For example, (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxy 2-hydroxypropyltrimethylammonium chloride, (meth) acryloylaminopropyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, ( Examples thereof include (meth) acryloyloxy 2-hydroxypropyldimethylbenzylammonium chloride, (meth) acryloylaminopropyldimethylbenzylammonium chloride, and a copolymer of these monomers and nonionic monomers may be used. Also, diallylamine polymers such as dimethyldiallylammonium chloride polymer can be used.

Examples of nonionic polymers include (co) polymers of the above nonionic monomers, polyvinyl alcohol, styrene / maleic anhydride copolymers or fully amidated products of butene / maleic anhydride copolymers. Etc.

The molecular weight of the ionic polymer is 5,000 to 3 million, preferably 50,000 to 1.5 million. The molecular weight of the nonionic polymer is 1,000 to 1,000,000, preferably 1,000 to 500,000. The amount of these polymer dispersants added to the monomer is 1/100 to 1/10, preferably 2/100 to 5/100.

These various polymerizations are carried out under a nitrogen atmosphere, with a polymerization initiator such as 2,
Initiation of water-soluble azo polymerization such as 2'-azobis (amidinopropane) dihydrochloride or 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride A water-soluble redox polymerization initiator such as an agent or a combination of ammonium persulfate and sodium hydrogen sulfite is added, and radical polymerization is performed with or without stirring.

As the water-soluble polymer of the present invention, a water-soluble cationic or water-soluble amphoteric polymer can be used. In particular, in the case of a water-soluble amphoteric polymer, an aqueous solution having a concentration of 0.1% by mass is used. It is preferable that pH is 4.0 or less normally, More preferably, it is 3.0 or less. If the aqueous solution pH exceeds 4.0, sufficient performance cannot be obtained. Therefore, an acidic substance is blended. There are two reasons for this. That is, since the water-soluble amphoteric polymer is blended, an ion complex is formed in the solution pH range of about 5 to about 9, and the solution becomes cloudy. This is because when the ion complex is generated and added to a treatment control such as sludge, the performance decreases. In the range where the pH is higher than about 5, the water-soluble (meth) acrylic polymer used in the present invention is easily hydrolyzed and deteriorates. The 0.1 mass% concentration is a solution concentration close to the lower limit when added to a treated control. In order to prevent these phenomena, the pH of the aqueous solution is preferably 4 or less.

Examples of such acidic substances include hydrochloric acid, sulfuric acid, acetic acid, sulfamic acid, citric acid, fumaric acid, succinic acid, adipic acid and the like as inorganic or organic acids. The addition amount of these acidic substances is 5 to 20% by mass, preferably 7 to 15% by mass in terms of solid content of the water-soluble polymer, and the pH is 4 or less even when dissolved in a concentration of 0.1% by mass. Can be secured.

The present invention relates to PAC, titanium flocculant, polydiallylammonium salt and acrylamide low molecular weight copolymer, anionic polyacrylamide copolymer, which are inorganic aluminum flocculants conventionally used for raw water for drinking water. Instead, a water-soluble polymer having a charge inclusion rate of 35% to 90% is used. The following can be considered as this reason. That is, the linear water-soluble polymer exists in a state where the molecules are spread in water. It is considered that the aggregating action of a high-molecular weight cationic water-soluble polymer such as a polymerization system is caused by a binding action of a large number of suspended particles by a so-called “cross-linking adsorption action” by a molecular chain of the water-soluble polymer. In general, raw water for drinking water contains dissolved or dispersed organic substances such as humic substances or soluble COD components in addition to inorganic suspended particles such as mud and sand. However, humic substances and the like are small molecules, and are present in water as stable colloids that are charged anionic. For this reason, the surface charge is neutralized by PAC or the like to generate fine flocs. On the other hand, polydiallylammonium salts and acrylamide low molecular weight copolymers can remove organic substances such as humic substances by adsorption, but titanium-based flocculants and anionic polyacrylamide copolymers are inorganic suspensions. Organic substances cannot be removed even if they have particle agglomeration and precipitation effects.

On the other hand, the crosslinkable water-soluble polymer suppresses the spread of molecules in water by crosslinking. For this reason, it exists as a “density packed” molecular form, and when the crosslinking proceeds further, it becomes a water-swellable fine particle. It is considered efficient that the above-mentioned “density-packed” molecular form is usually used as a polymer flocculant. When a crosslinkable water-soluble polymer is added to raw water for drinking water, unlike the linear water-soluble polymer, no huge floc is generated due to cross-linking adsorption. Similar to the polymer, functions such as neutralization of surface charge are expressed and fine flocs are generated. That is, it reacts with organic colloids such as humic substances to produce fine flocs. On the other hand, since the molecular form is larger than PAC, titanium-based flocculant, polyamine-based polycondensation polymer or polydiallylammonium salt and acrylamide low molecular weight copolymer, inorganic suspended particles such as mud and sand can be efficiently removed. . That is, it is considered that water-soluble polymers have more particulate properties as the degree of crosslinking increases. The water-soluble polymer having a high degree of crosslinking used in the present invention is considered to have an intermediate property between water-insoluble particles having undergone crosslinking and a linear water-soluble polymer.

The water-soluble polymer having a high degree of cross-linking used in the present invention can reduce the risk of Alzheimer's disease compared to PAC which is a conventionally used inorganic aluminum-based flocculant, and also includes a titanium-based flocculant or an anionic polyacrylamide copolymer. Compared with materials, organic substances such as humic substances can be removed, and inorganic suspended particles such as mud and sand can also be efficiently removed.

When the water flocculant composed of the water-soluble polymer of the present invention is added to the raw water subjected to the flocculation treatment in the water purification plant in the flocculation stirring tank and stirred, a very fine floc is quickly formed, and then the anionic polyacrylamide By using a system flocculant, a large floc can be formed and solid-liquid separation can be performed. Therefore, the coagulant for clean water according to the present invention does not prevent the use of polyaluminum chloride as another inorganic coagulant, or an organic polymer such as sodium alginate or sodium polyacrylate.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

(Synthesis Example 1) In a reaction vessel equipped with a stirrer and a temperature controller, 126.0 g of isoparaffin having a boiling point of 190 ° C to 230 ° C, 6.0 g of sorbitan monooleate and polyricinoleic acid / polyoxyethylene block copolymer 0 .6 g was charged and dissolved. Separately, 55.0 g of deionized water and 19.7 g of a 60% aqueous solution of acrylic acid (abbreviated as AAC) were mixed, and 119.1 g of an 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), methacryloyloxyethyltrimethylammonium. Chloride (hereinafter abbreviated as DMC) 80% aqueous solution 42.6 g, acrylamide (abbreviated as AAM) 50% aqueous solution 116.4 g, and methylenebisacrylamide 0.1% by weight aqueous solution 3.0 g (0.0015% by weight monomer) ) Were collected and each was mixed and completely dissolved. Thereafter, the pH was adjusted to 3.95, the oil and the aqueous solution were mixed, and stirred and emulsified with a homogenizer at 1000 rpm for 15 minutes. The monomer composition at this time is DMC / DMQ / AAC / AAM = 10/30/10/50 (mol%, trial production-1).

After adding 2.0 g of isopropyl alcohol 10 mass% aqueous solution (0.1 mass% with respect to monomer) to the obtained emulsion, keeping the temperature of the monomer solution at 30 to 33 ° C., and performing nitrogen substitution for 30 minutes 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride 2.0 g (0.01% by weight monomer) was added. The polymerization reaction was started. The reaction was completed at a reaction temperature of 32 ± 2 ° C. for 12 hours to complete the reaction. After polymerization, 7.5 g of polyoxyethylene tridecyl ether (1.5% by mass of the emulsion) was added and mixed as a phase inversion agent to the resulting water-in-oil emulsion to prepare a sample for use in the test (Sample 1). . The charge inclusion rate of the obtained sample was measured with a PCD titration apparatus manufactured by Mutech, and the weight average molecular weight determined by the light scattering method was about 6.7 million. By a similar operation, a water-in-oil emulsion comprising DMQ / AAM = 80/20 (mol%, trial production-2) and DMQ / AAM = 50/50 (mol%, trial production-3) was synthesized. The results are shown in Table 1.

(Creation of water-in-oil emulsion dry product)
Regarding water-in-oil emulsion trial production-1 to trial production-3, spray-dried powder was prepared using a spray dryer without adding a phase inversion agent. The names of the prototypes after drying are designated as prototype-4 to prototype-6.
In addition, water-in-oil emulsion prototype-1 to prototype-3 were put in a drier in the state of dispersion to obtain a dried product, which was then pulverized to prepare a powder product. The names of the prototypes after drying are designated as prototype-7 to prototype-9. The above results are summarized in Table 1.

(Comparative Synthesis Example 1) In a reaction vessel equipped with a stirrer and a temperature control device, 126.0 g of isoparaffin having a boiling point of 190 ° C to 230 ° C, 6.0 g of sorbitan monooleate, and a polyricinoleic acid / polyoxyethylene block copolymer 0.6 g was charged and dissolved. Separately, 55.0 g of deionized water and 19.7 g of a 60% aqueous solution of acrylic acid (abbreviated as AAC) were mixed, and 119.1 g of an 80% aqueous solution of acryloyloxyethyltrimethylammonium chloride (hereinafter abbreviated as DMQ), methacryloyloxyethyltrimethylammonium. Chloride (hereinafter abbreviated as DMC) 80% aqueous solution 42.6 g, acrylamide (abbreviated as AAM) 50% aqueous solution 116.4 g, and methylenebisacrylamide 0.1% by weight aqueous solution 1.0 g (based on monomer 0.0004% by weight) ) Were collected and each was mixed and completely dissolved. Thereafter, the pH was adjusted to 3.95, the oil and the aqueous solution were mixed, and stirred and emulsified with a homogenizer at 1000 rpm for 15 minutes. The monomer composition at this time is DMC / DMQ / AAC / AAM = 10/30/10/50 (mol%, comparative sample-1).

After adding 2.0 g of isopropyl alcohol 10 mass% aqueous solution (0.1 mass% with respect to monomer) to the obtained emulsion, keeping the temperature of the monomer solution at 30 to 33 ° C., and performing nitrogen substitution for 30 minutes 2,2'-azobis [2- (5-methyl-2-imidazolin-2-yl) propane] dihydrochloride 2.0 g (0.01% by weight monomer) was added. The polymerization reaction was started. The reaction was completed at a reaction temperature of 32 ± 2 ° C. for 12 hours to complete the reaction. After the polymerization, 7.5 g of polyoxyethylene tridecyl ether (1.5% by mass of the emulsion) was added to and mixed with the resulting water-in-oil emulsion as a phase inversion agent to prepare a sample for the test. The charge inclusion rate of the obtained sample was measured with a PCD titration apparatus manufactured by Mutech, and the weight average molecular weight determined by the light scattering method was about 6.7 million. By the same operation, a water-in-oil emulsion composed of DMQ / AAM = 80/20 (mol%, comparative sample-2) and DMQ / AAM = 50/50 (mol%, comparative sample-3) was synthesized.

Regarding water-in-oil emulsion comparisons -1 to -3, spray-dried powders were prepared using a spray dryer without using a phase inversion agent polyoxyethylene tridecyl ether. The prototype names after drying are referred to as comparison-4 to comparison-6. The above results are summarized in Table 1.

(Table 1)
DMC; methacryloyloxyethyltrimethylammonium chloride,
DMQ; acryloyloxyethyltrimethylammonium chloride AAC; acrylic acid, AAM; acrylamide, charge inclusion rate;%,
Product form: EM; water-in-oil emulsion, SDP; spray-dried product,
DDP: Dryer dryer

Example 1
Sample-4 was obtained by collecting 500 ml of raw tap water (turbidity 20 NTU) collected from a water purification plant in a 500 ml beaker and setting it in a jar tester (MIS-6 manufactured by Miyamoto Seisakusho Co., Ltd.) and drying a water-in-oil emulsion. -An aqueous solution containing 0.1% by mass of Sample-9 was added so that each prototype was 1 ppm relative to the raw water, stirred at 150 rpm for 30 seconds, stirred at 80 rpm for 30 seconds, and then stirred at 40 rpm for 30 seconds. Let stand for 3 minutes. Thereafter, the treated water is withdrawn from the position 2 cm deep from the liquid surface, and the turbidity is measured with a turbidimeter (2100P manufactured by HACH). (Total organic carbon) was measured. The results are shown in Table 2.

(Comparative test)
A test was conducted using comparative samples, Comparative-4 to Comparative-6, which were obtained by drying a water-in-oil emulsion by the same procedure. At the same time, polyacrylamide anionic polymer flocculant (anionization degree 20 mol%, molecular weight 10 million, comparative -7), sodium alginate (compared-8), polyaluminum chloride (PAC) (compared-9) were also tested. It was. Polyaluminum chloride (PAC) was added to 20 ppm with respect to raw tap water. The results are shown in Table 2.

(Table 2)
Turbidity unit is NTU, TOC unit is mg / L

Claims (5)

A water-soluble polymer having a charge inclusion rate of 35% to 90% represented by the following definition, wherein the water-soluble polymer comprises a monomer represented by the following general formula (1) and a crosslinkable monomer: A flocculant for water supply comprising a water-soluble polymer obtained by polymerizing a monomer mixture contained as an essential component.
Definition 1) Charge in the case of a cationic cross-linkable water-soluble ionic polymer and a cross-linkable water-soluble ionic polymer that is amphoteric and has a positive molar concentration difference between a cationic monomer and an anionic monomer Inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a cross-linkable water-soluble ionic polymer aqueous solution adjusted to pH 4.0 with acetic acid with an aqueous potassium polyvinyl sulfonate solution. β is added to a crosslinkable water-soluble ionic polymer aqueous solution adjusted to pH 4.0 with acetic acid in an amount sufficient to neutralize the charge of the crosslinkable water-soluble ionic polymer, and then Titration volume obtained by subtracting the titration titrated with polydiallyldimethylammonium chloride aqueous solution from the blank value (blank value: Polyvinyl dimethylammonium chloride aqueous solution with polydiallyldimethylammonium chloride aqueous solution when no crosslinkable water-soluble ionic polymer aqueous solution was added) Titration titration).
Definition 2) Charge in the case of an anionic crosslinkable water-soluble ionic polymer and a crosslinkable water-soluble ionic polymer that is amphoteric and has a negative difference in molar concentration between the cationic monomer and the anionic monomer Inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a cross-linkable water-soluble ionic polymer aqueous solution adjusted to pH 10.0 with ammonia with a polydiallyldimethylammonium chloride aqueous solution. β is added to a crosslinkable water-soluble ionic polymer aqueous solution adjusted to pH 10.0 with ammonia in an amount sufficient to neutralize the charge of the crosslinkable water-soluble ionic polymer with a polydiallyldimethylammonium chloride aqueous solution, Titrate after titration with potassium polyvinylsulfonate aqueous solution was subtracted from blank value (blank value: diallyldimethylammonium chloride aqueous solution was titrated with potassium polyvinylsulfonate aqueous solution when no crosslinkable water-soluble ionic polymer aqueous solution was added. Titration).
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl group having 1 to ₃ carbon atoms, an alkoxy group or a benzyl group, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group. , Same or different. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion. The water-soluble polymer is a mixture aqueous solution containing the monomer represented by the general formula (1) and a crosslinkable monomer as a disperse phase and a water-immiscible organic liquid as a continuous phase. The water-soluble flocculant according to claim 1, which is a water-soluble polymer powder obtained by drying a water-in-oil emulsion obtained after emulsification with a surfactant. The coagulation rate of the monomer represented by the general formula (1) constituting the water-soluble polymer is 20 to 95 mol%. Agent. When the water-soluble polymer is amphoteric, when the water-soluble amphoteric polymer is dissolved in 0.1% by mass or more, an acidic substance in an amount that makes the solution pH 4 or less is mixed. The flocculant for clean water in any one of 1-3. When separating the suspended matter in the raw water for clean water, it is a water-soluble polymer having a charge inclusion rate of 35% or more and 90% or less represented by the following definition, wherein the water-soluble polymer is represented by the following general formula (1) A method for separating a suspension in raw water for water supply, comprising using a water-soluble polymer obtained by polymerizing a monomer mixture containing a monomer represented by formula (1) and a crosslinkable monomer as essential components.
Definition 1) Charge in the case of a cationic cross-linkable water-soluble ionic polymer and a cross-linkable water-soluble ionic polymer that is amphoteric and has a positive molar concentration difference between a cationic monomer and an anionic monomer Inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a cross-linkable water-soluble ionic polymer aqueous solution adjusted to pH 4.0 with acetic acid with an aqueous potassium polyvinyl sulfonate solution. β is added to a crosslinkable water-soluble ionic polymer aqueous solution adjusted to pH 4.0 with acetic acid in an amount sufficient to neutralize the charge of the crosslinkable water-soluble ionic polymer, and then Titration volume obtained by subtracting the titration titrated with polydiallyldimethylammonium chloride aqueous solution from the blank value (blank value: Polyvinyl dimethylammonium chloride aqueous solution with polydiallyldimethylammonium chloride aqueous solution when no crosslinkable water-soluble ionic polymer aqueous solution was added) Titration titration).
Definition 2) Charge in the case of an anionic crosslinkable water-soluble ionic polymer and a crosslinkable water-soluble ionic polymer that is amphoteric and has a negative difference in molar concentration between the cationic monomer and the anionic monomer Inclusion rate [%] = (1−α / β) × 100
α is a titration amount obtained by titrating a cross-linkable water-soluble ionic polymer aqueous solution adjusted to pH 10.0 with ammonia with a polydiallyldimethylammonium chloride aqueous solution. β is added to a crosslinkable water-soluble ionic polymer aqueous solution adjusted to pH 10.0 with ammonia in an amount sufficient to neutralize the charge of the crosslinkable water-soluble ionic polymer with a polydiallyldimethylammonium chloride aqueous solution, Titrate after titration with potassium polyvinylsulfonate aqueous solution was subtracted from blank value (blank value: diallyldimethylammonium chloride aqueous solution was titrated with potassium polyvinylsulfonate aqueous solution when no crosslinkable water-soluble ionic polymer aqueous solution was added. Titration).
General formula (1)
R ₁ is hydrogen or a methyl group, R ₂ and R ₃ are an alkyl group having 1 to ₃ carbon atoms, an alkoxy group or a benzyl group, and R ₄ is hydrogen, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group or a benzyl group. , Same or different. A represents oxygen or NH, B represents an alkylene group or alkoxylene group having 2 to 4 carbon atoms, and X ₁ represents an anion.