JP2012245435A - Polymer flocculant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polymer flocculant which forms a coarse flock having an excellent stability in the treatment of sludge and wastewater, and whose flocculation treatment speed is fast.SOLUTION: The polymer flocculant includes a (co)polymer having 10 mol% or more of a constitutional unit that is comprised of a monomer (M1) shown by formula (1). In the formula, Ris a hydrogen atom or a methyl group, Ris an alkylene group of 1-10 carbon atoms, R-Rare each independently an alkyl group of 1-15 carbon atoms, and Zis Clor 1/2 SO.

Description

  The present invention relates to a polymer flocculant. More specifically, the present invention relates to a polymer flocculant excellent in floc coarsening.

  Conventionally, water-soluble polymers have been used for sludge treatment such as sewage and human waste, wastewater treatment such as general industrial wastewater, mud treatment in civil engineering, and sedimentation and separation of muddy water during reclamation. For example, for the dehydration of organic sludge such as sludge and wastewater, cationic polymers such as (meth) acryloyloxyethyltrimethylammonium chloride polymer, acrylamide-acryloyloxyethyltrimethylammonium chloride copolymer and polyvinylamidine An amphoteric polymer flocculant (for example, see Patent Document 3) such as a flocculant (for example, see Patent Documents 1 and 2) or an acrylamide-acrylic acid- (meth) acryloyloxyethyltrimethylammonium chloride copolymer can be used. It is disclosed.

  Also, anionic polymer flocculants characterized by increasing the agglomeration density by graft polymerization of water-soluble monomers to water-soluble polymers for the purpose of wastewater treatment or civil engineering fields such as construction and reclamation Is also disclosed (see, for example, Patent Documents 4 and 5).

In recent years, especially regarding the dewatering of organic sludge, the need for improving the dewatering rate has increased due to the increase in the amount of sludge generated, the increase in incineration disposal costs of dewatered cake due to the difficult dewatering of sludge properties, and the In view of the tightness of landfill sites when landfilled as it is, a polymer flocculant capable of forming stronger and coarser flocs and greatly reducing the water content during dehydration is desired.
However, among the above prior arts, the cationic polymer flocculant and the amphoteric polymer flocculant have a problem that the floc aggregation density is low, and the anionic polymer flocculant that is said to have increased the aggregation density is: There is a problem that the graft polymerization is not precisely controlled and easily insolubilized, and none of these have satisfied the above needs.

JP 63-274409 A JP 2000-107513 A Japanese Patent Laid-Open No. 3-189000 JP-A-6-254305 JP-A-6-254306

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a polymer flocculant that forms a coarse floc that is excellent in stability in the treatment of sludge and wastewater and that has a high flocculation speed. There is to do.

  The inventor of the present invention has reached the present invention as a result of studies to achieve the above object. That is, the present invention provides a (co) weight having 10 mol% or more of a structural unit composed of the monomer (M1) represented by the general formula (1) and / or the monomer (M2) represented by the general formula (2). It is a polymer flocculant made of coalescence.

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkylene group having 1 to 10 carbon atoms, R ^{3 to} R ⁵ are each independently an alkyl group having 1 to 15 carbon atoms, Z ⁻ is Cl ⁻ or 1 / 2SO ₄ ^2- represents. ]

[Wherein, R ⁶ is a hydrogen atom or a methyl group, R ⁷ and R ⁸ are each independently an alkylene group having 1 to 10 carbon atoms, R ^{9 to} R ¹³ are each independently an alkyl group having 1 to 15 carbon atoms, Z ^- is Cl ^- represents a or 1 / 2SO ₄ ^2-. ]

  Since the polymer flocculant of the present invention forms strong and coarse flocs in the treatment of sludge and wastewater, the formed flocs are difficult to break and re-disperse, and the flocculant treatment rate can be significantly increased.

  The polymer flocculant of the present invention has 10% by mole or more of structural units composed of the monomer (M1) represented by the general formula (1) and / or the monomer (M2) represented by the general formula (2). It is characterized by comprising a (co) polymer.

In general formula (1), R ¹ is a hydrogen atom or a methyl group, R ² is an alkylene group having 1 to 10 carbon atoms, R ^{3 to} R ⁵ are each independently an alkyl group having 1 to 15 carbon atoms, and Z ⁻ is Cl ^−. Or represents 1 / 2SO ₄ ^2- .

From the viewpoint of aggregation performance (particularly floc coarsening), R ¹ , R ³ , R ⁴ and R ⁵ are preferably methyl groups, R ² is an ethylene group, and Z ⁻ is Cl ⁻ .

In general formula (2), R ⁶ is a hydrogen atom or a methyl group, R ⁷ and R ⁸ are each independently an alkylene group having 1 to 10 carbon atoms, and R ^{9 to} R ¹³ are each independently an alkyl group having 1 to 15 carbon atoms. group, Z ^- is Cl ^- represents a or 1 / 2SO ₄ ^2-.

From the viewpoint of aggregating performance (particularly floc coarsening), R ⁶ and R ^{9 to} R ¹³ are preferably methyl groups, R ⁷ and R ⁸ are ethylene groups, and Z ⁻ is Cl ⁻ .

  A monomer (M1) and a monomer (M2) may be used individually by 1 type, or may use 2 or more types together.

  The polymer constituting the polymer flocculant of the present invention may be a monomer (M1) or a homopolymer of monomer (M2) or a copolymer of monomer (M1) and monomer (M2). It may be a monomer (M1) and / or a copolymer of the monomer (M2) and another monomer.

  Examples of other monomers include nonionic monomers, anionic monomers, and cationic monomers.

  Nonionic monomers include hydrophilic monomers (acrylamide, acrylonitrile, vinylpyrrolidone, etc.) having a solubility in water at 20 ° C. of 10 or more, and hydrophobicity having a solubility in water at 20 ° C. of less than 10. Monomer [C4-C30 (cyclo) alkyl (meth) acrylate, etc., for example, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, lauryl (meth) acrylate), octadecyl (meth) ) Acrylate, cyclohexyl (meth) acrylate and cyclooctyl (meth) acrylate].

  Examples of the anionic monomer include acrylic acid (salt), acrylamidomethylpropanesulfonic acid (salt), and itaconic acid (salt). The cation used when the anionic monomer forms a salt includes alkali. Examples include metal cations and lower aminium cations.

  Examples of the cationic monomer include (meth) acryloyloxyethyltrimethylammonium chloride, (meth) acryloyloxyethyldimethylbenzylammonium chloride, dimethyldiallylammonium methylsulfate, and the like.

  Among these, acrylamide, acrylonitrile, acrylic acid, (meth) acryloyloxyethyltrimethylammonium chloride are preferable from the viewpoint of aggregation performance, and acrylamide and (meth) acryloyloxyethyltrimethylammonium chloride are more preferable.

  Other monomers may be used alone or in combination of two or more.

  When copolymerizing the monomer (M1) and / or the monomer (M2) and other monomers, the amount of the monomer (M1) and / or the monomer (M2) relative to the total monomers From the viewpoint of agglomeration performance (particularly floc coarsening), it is usually at least 10 mol%, preferably at least 50 mol%.

  The form of the polymer flocculant of the present invention is not particularly limited, and can take any form such as powder, film, aqueous solution, w / o emulsion, or suspension.

The polymer flocculant of the present invention can be produced by a known method such as aqueous solution polymerization, emulsion polymerization using water and an organic solvent, suspension polymerization and the like.
In the case of aqueous solution polymerization, after replacing the interior of the system with an inert gas so that the monomer concentration becomes 10 to 80% by weight, a known polymerization catalyst [for example, a catalyst such as ammonium persulfate and potassium persulfate is added. Sulfates; organic peroxides such as benzoyl peroxide; azo compounds such as 2,2′-azobis- (amidinopropane) hydrochloride and azobiscyanovaleric acid; redox catalysts, etc.] at about 20-100 ° C. Polymerize for several hours. Moreover, after adding a photosensitizer, you may irradiate an ultraviolet-ray etc.

  The amount of the polymer flocculant of the present invention varies depending on the type of sludge or waste water, the size of suspended particles, etc., but based on the weight of evaporation residue in sludge and the like (hereinafter abbreviated as TS), Usually 0.01 to 10%, and the lower limit preferable from the viewpoint of aggregation performance is 0.1%, more preferably 0.5%, particularly preferably 1%, and the upper limit preferable from the viewpoint of processing cost is 5%, more preferably 3%. %, Particularly preferably 2%.

  The polymer flocculant of the present invention may be used in combination with other flocculants as necessary. Other flocculants include cationic polymers such as methacryloyloxyethyltrimethylammonium chloride polymer, acrylamide-acryloyloxyethyltrimethylammonium chloride copolymer, acrylamide-acryloyloxyethyltrimethylammonium chloride copolymer, and vinylamidine polymer. Flocculants; Anionic polymer flocculants such as acrylamide-sodium acrylate copolymer; Amphoteric polymer flocculants such as acrylamide-acrylic acid-acryloyloxyethyltrimethylammonium chloride copolymer.

When the polymer flocculant of the present invention is used by adding it to sludge or wastewater, depending on the sludge or wastewater, sulfate band, polyaluminum chloride, ferric chloride, ferric sulfate, polyiron sulfate, slaked lime, etc. An inorganic coagulant and / or an organic coagulant such as aniline-formaldehyde polycondensate hydrochloride, polyvinylbenzyltrimethylammonium chloride and di (meth) allyldimethylammonium chloride may be used in combination. When using in combination, it may be added in advance to the polymer flocculant, or after adding an inorganic coagulant and / or an organic coagulant to sludge or wastewater in advance to cause primary aggregation, the polymer coagulant is added. Also good.
The amount of inorganic coagulant and / or organic coagulant added varies depending on the type of sludge or waste water, the size of suspended particles and the type of coagulant used, etc. The inorganic coagulant is usually 20% by weight or less, preferably from 0.5 to 10% by weight, more preferably from 1 to 8% by weight, particularly preferably from 3 to 5% by weight from the viewpoint of aggregation performance. The agent is usually 1% by weight or less, preferably from 0.01 to 0.5% by weight, more preferably from 0.025 to 0.2% by weight, particularly preferably from 0.05 to 0.15% by weight, from the viewpoint of aggregation performance. It is.

  Examples of the dehydration method (solid-liquid separation method) of floc sludge formed by the above processing method include a filtration device (membrane or column filtration device), a concentration device (gravity, centrifugation, pressurized flotation or granulation concentration). And the like, and a method using a dehydrator (such as a centrifugal dehydrator, a belt press, a filter press, a screw press, and a vacuum dehydrator). Among these, from the viewpoint of the excellent aggregation performance of the polymer flocculant of the present invention, a method using a concentrator or a dehydrator is preferable, and a centrifugal, belt press, filter press or screw press dehydrator is more preferable. This method is used.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this. In addition, the part in an Example shows a weight part and% shows weight%.

Production Example 1
A reaction vessel was charged with 144 parts of 1- (2-hydroxyethyl) -4-methylpiperazine, 1 part of hydroquinone, and 200 parts of tetrahydrofuran, heated to 80 ° C. while bubbling air, and 115 parts of methacrylic acid chloride was added over 1 hour. And slowly dropped. After completion of the dropwise addition, the reaction was further continued for 1 hour. After the reaction, the reaction solution was cooled to room temperature, 100 parts of water was added, and the mixture was separated after shaking, and the solvent was removed from the organic layer under reduced pressure to obtain 202 parts of an intermediate.
200 parts of the intermediate obtained in the reaction vessel and 200 parts of water are charged, and 105 parts of methyl chloride are blown at 40 ° C. with stirring. In the above general formula (1), R ¹ and R ^{3 to} R ⁵ are methyl groups, R 495 parts of an aqueous monomer solution (M-1) in which ² is an ethylene group and Z ⁻ is Cl ⁻ are obtained. The monomer concentration of the monomer aqueous solution (M-1) was 60%.

Production Example 2
In the same manner as in Production Example 1 except that 144 parts of 1- (2-hydroxyethyl) -4-methylpiperazine was replaced with 146 parts of 3,6-dimethyl-3,6-diazaheptan-1-ol, the above general formula ( In 2), an aqueous monomer solution (M-2) in which R ⁶ and R ^{9 to} R ¹³ are methyl groups, R ⁷ and R ⁸ are ethylene groups, and Z ⁻ is Cl ⁻ is obtained. The monomer concentration of the aqueous monomer solution (M-2) was 60%.

Examples 1 to 4 and Comparative Example 1
A monomer or an aqueous monomer solution was charged into a reaction vessel equipped with a stirrer based on the formulation shown in Table 1, and water was added in an amount such that the monomer concentration was 34%, and the mixture was stirred uniformly. Under stirring, the pH (20 ° C.) of the aqueous monomer solution was adjusted to 3.3 with sulfuric acid.
Next, after sufficiently replacing the system with nitrogen, the temperature was raised to 40 ° C., 0.1 part of a 2% methanol solution of triethylene glycol dithiol as a chain transfer agent for radical polymerization, and 2,2 ′ as a polymerization initiator. -1 part of a 10% aqueous solution of azobis (2-amidinopropane) dihydrochloride and 1 part of a 0.1% aqueous solution of hydrogen peroxide, 1 part of a 0.15% aqueous solution of ascorbic acid as redox agent and ferrous sulfate After adding 1 part of a 0.05% aqueous solution and stirring, polymerization was performed at a solution temperature of 40 to 50 ° C. for 10 hours, and the temperature was further raised to 70 ° C. for aging for 1 hour to complete the polymerization. Thereafter, the contents were taken out, chopped into minced shapes having a diameter of about 5 mm, dried with hot air at 80 ° C. for 2 hours, and then pulverized to obtain a powdery polymer flocculant having a volume average particle size of 1,000 μm. .

  In Table 1, DAMQ is methyl chloride quaternary ammonium salt of N, N-dimethylaminoethyl methacrylate, and MMA is methyl methacrylate.

Using the obtained polymer flocculant and sludge collected at a sewage treatment plant (pH 6.3, TS 1.5%, organic content 84%), floc particle size, floc strength and moisture content of dehydrated cake were evaluated by the following evaluation methods. Evaluated. The results are shown in Table 1.
In addition, TS and organic content (ignition loss) in sludge were performed according to the analysis method described in the sewage test method (Japan Sewerage Association, 1984 version).

<Flock particle size>
200 g of sludge was collected in a 500 mL beaker, and a plate-like PVC stirring blade (blade width 5 cm, height 2 cm, thickness) on a stirring bar of a jar tester (model “JMD-6HS-A” manufactured by Miyamoto Riken Kogyo Co., Ltd.) 0.2 cm) using a stirrer attached to the stirrer so that the two pieces look like a cross when viewed from the extension of the shaft of the stirrer and the distance between the stirring blades (interval between the central portions) is 5 cm Then, while stirring the sludge at a rotation speed of 120 rpm, 13 g of 0.2 wt% polymer flocculant aqueous solution in which 1.0 g of the polymer flocculant was completely dissolved in 499 g of water in advance was added at once with a syringe or the like. Then, after stirring is continued for 30 seconds, the size of the floc formed by stopping the stirring (floc particle diameter at 120 rpm) is quickly observed visually. Subsequently, after further stirring for 30 seconds at a rotational speed of 300 rpm, the size of the floc formed by stopping the stirring (the floc particle diameter at a rotational speed of 300 rpm) is again visually observed.

<Flock strength>
The floc particle diameters at the rotation speeds of 120 rpm and 300 rpm are compared, and the floc strength is evaluated from the change of the floc particle diameter according to the following criteria.
A: Very strong (no change in particle size)
○: Strong (partially subdivided)
×: weak (overall segmentation)

<Dehydrated cake moisture content>
A Nutsche laid with a nylon filter cloth is set on a 300 mL graduated cylinder, and the sludge after the above floc particle size evaluation is put on the funnel at a stretch and filtered. Part of the sludge on the obtained filter plate was collected with a spatula and dehydrated using a press filter dehydration tester (pressing pressure 1 kg / cm ² , pressing time 60 seconds), and about 3 g of dehydrated cake was collected in a petri dish (diameter 70 mm, depth 10 mm) (weigh this weight as (W1)), dried in a circulating drier at 105 ± 5 ° C. for 8 hours, and then the weight of the dry cake remaining in the petri dish (W2 ) And the moisture content of the dehydrated cake is calculated from the following equation.
Dehydrated cake moisture content (%) = {(W1) − (W2)} × 100 / (W1)

  Since the polymer flocculant of the present invention exhibits unprecedented high floc strength and floc coarsening, the polymer flocculant for dehydration treatment of organic sludge or inorganic sludge generated by treatment of sludge or waste water, etc. It can be used and is particularly suitable for dehydration treatment of organic sludge.

Claims (2)

A polymer comprising a (co) polymer having 10 mol% or more of a structural unit comprising the monomer (M1) represented by the general formula (1) and / or the monomer (M2) represented by the general formula (2). Flocculant.

[Wherein, R ¹ is a hydrogen atom or a methyl group, R ² is an alkylene group having 1 to 10 carbon atoms, R ^{3 to} R ⁵ are each independently an alkyl group having 1 to 15 carbon atoms, Z ⁻ is Cl ⁻ or 1 / 2SO ₄ ^2- represents. ]

[Wherein, R ⁶ is a hydrogen atom or a methyl group, R ⁷ and R ⁸ are each independently an alkylene group having 1 to 10 carbon atoms, R ^{9 to} R ¹³ are each independently an alkyl group having 1 to 15 carbon atoms, Z ^- is Cl ^- represents a or 1 / 2SO ₄ ^2-. ] R ¹ and R ^{3 to} R ⁵ in the general formula (1) are methyl groups, R ² is an ethylene group, Z ⁻ is Cl ⁻ , and R ⁶ and R ^{9 to} R ¹³ in the general formula (2) are methyl group, R ⁷ and R ⁸ is an ethylene group, Z ^- is Cl ^- polymer flocculant according to claim 1, wherein the.