JP3924056B2 - Sludge dewatering agent and sludge treatment method - Google Patents

Description

【０１１１】
表１に示すように、カチオン性高分子凝集剤と、分子量が１１０万以上のスチレン系重合体スルホン化物の塩である重合体１〜重合体８を組み合わせた場合には、濾過速度が速く、濾液濁度が低く、ケーキの剥離性も良好であり、またケーキの含水率も低い。これに対して、スチレン系重合体スルホン化物の塩であっても分子量が１１０万未満のもの（比較用重合体１〜比較用重合体４）を使用した場合や他の種類の重合体（比較用重合体５）を使用した場合、またカチオン性高分子凝集剤のみしか使用しない場合には、濾過速度が遅く、濾液濁度も高い。また、ケーキ剥離性も不良であり、ケーキ含水率も高い。
【０１１２】
このことから、カチオン性高分子凝集剤と組み合わせて使用する重合体としてはスチレン系重合体スルホン化物またはその塩が好適であり、さらにこのスチレン系重合体スルホン化物またはその塩は重量平均分子量が１１０万以上であることが必要であることがわかった。
【０１１３】
製紙工場廃水に対する凝集効果の評価
製紙工場廃水（ｐＨ：７．５、懸濁物質（ＳＳ）濃度：１２０ｐｐｍ）を用意し、複数本の容器に分注した。
【０１１４】
そして、各廃水に、無機凝集剤を廃水量に対して４００ｐｐｍ添加した後、重合体１，重合体３，重合体９及び比較用重合体４，比較用重合体５のそれぞれを廃水量に対して２ｐｐｍ添加した後、静置し、その際の懸濁粒子の沈降速度を測定した。
【０１１５】
次に、各凝集液をポリプロピレン製濾布（商品名ＰＰ２６ＦＫ）で濾過し、濾液の濁度を透過型濁度計により測定するとともにＣＯＤ（化学的酸素要求量）を測定した。
【０１１６】
続いて、濾過の際に残渣となった汚泥を、２枚の濾布で挟み、この挟んだ状態で圧搾試験機で１分間圧搾を行い、得られた汚泥のケーキの含水率を調べた。
【０１１７】
以上のようにして測定された沈降速度、上澄み液の濁度、ＣＯＤ、ケーキ含水率の結果を表２に示す。
【０１１８】
【表２】

【０１１９】
表２に示すように、無機凝集剤と、分子量が１１０万以上のスチレン系重合体スルホン化物またはその塩である重合体１，重合体３，重合体９を組み合わせた場合には、沈降速度が速く、濾液濁度やＣＯＤが低く、ケーキ含水率も低い。これに対して、スチレン系重合体スルホン化物の塩であっても分子量が１１０万未満のもの（比較用重合体４）を使用した場合や他の種類の重合体（比較用重合体５）を使用した場合には、沈降速度が遅く、濾液濁度やＣＯＤも高く、ケーキ含水率も高い。
【０１２０】
このことから、無機凝集剤と組み合わせて使用する重合体としてはスチレン系重合体スルホン化物またはその塩が好適であり、さらにこのスチレン系重合体スルホン化物またはその塩は重量平均分子量が１１０万以上であることが必要であることがわかった。
【０１２１】
【発明の効果】
以上の説明から明らかなように、本発明では 重量平均分子量が１１０万以上のスチレン系重合体スルホン化物及び／またはその塩を汚泥処理剤として用い、これとカチオン性高分子凝集剤及び／または無機凝集剤を組み合わせて汚泥の処理を行うので、フロックを生成した汚泥の濾過に際して高い濾過効率が得られ、しかも濁度の低い濾液が得られる。また処理によって生じたケーキの含水率も低く、ケーキと濾布との剥離も容易に行える。したがって、本発明によれば、汚泥の処理を効率良く行うことができ、また処理によって生じたケーキも少ない燃料使用量で焼却することが可能になるので、地球環境保全に大いに貢献することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sludge dewatering agent and a sludge treatment method used for the treatment of sludge such as sewage sludge, manure sludge or various industrial wastewater.
[0002]
[Prior art]
Sludge such as sewage sludge, sewage sludge or various industrial wastewater is treated by adding flocculant (dehydrating agent) to these sludges to agglomerate suspended substances to generate flocs, and the sludge that has generated these flocs is belted. It is performed by dehydrating with a breath dehydrator or a filter press dehydrator and separating into a solid component (cake) and water. In the treatment of such sludge, it is required that the moisture content of flocs and cakes generated in the treatment process is low, the filtration speed is high at the time of sludge filtration, and the peelability between the filter cloth and cake is good.
[0003]
Examples of the dehydrating agent used in the treatment of such sludge include quaternary salt polymers of dimethylaminoethyl acrylate or dimethylaminoethyl methacrylate, and dimethylaminoethyl acrylate or quaternary salt of dimethylaminoethyl methacrylate and acrylamide. In general, a cationic polymer flocculant such as a polymer is used alone, or a combination of these cationic polymer flocculants and an anionic polymer flocculant is used.
[0004]
Here, various polymers have been proposed as anionic polymer flocculants. For example, polyacrylic acid is proposed in JP-A-58-216707, and average molecular weight is disclosed in JP-A-2-298400. 1,000 to 1,000,000 sodium polystyrene sulfonates are described.
[0005]
[Problems to be solved by the invention]
However, when the cationic polymer flocculant is used alone, it cannot be said that the water content of the produced floc is high and the dehydrating property is not sufficient. Moreover, in the combination of the cationic polymer flocculant and the anionic polymer flocculant, even when sodium polyacrylate or sodium polystyrene sulfonate having an average molecular weight of 1,000 to 1,000,000 is used as the anionic flocculant, the sludge filtration rate is high. There was a problem that it was slow and processing efficiency was low.
[0006]
Therefore, the present invention has been proposed in view of such a conventional situation, the moisture content of the cake produced in the treatment process is low, and high filtration efficiency is obtained in the process of filtering sludge, and the filter cloth and An object of the present invention is to provide a sludge dewatering agent and a sludge treatment method capable of easily peeling a cake.
[0007]
[Means for Solving the Problems]
  In order to achieve the above object, the sludge dewatering agent of the present invention is:Having a cross-linked structure,Weight average molecular weight is 1.1 million~ 10 millionStyrene polymer sulfonated products and / or salts thereofAnd the sulfonic acid group content is 30 mol% or more based on the aromatic.It is characterized by this.
[0008]
  In addition, the sludge treatment method of the present invention,Having a cross-linked structure,Weight average molecular weight is 1.1 million~ 10 millionStyrene polymer sulfonated products and / or salts thereofAnd a sludge dehydrating agent having a sulfonic acid group content of 30 mol% or more with respect to the aromatic.And a cationic polymer flocculant and / or an inorganic flocculant are sequentially added to treat the sludge.
[0009]
  Having a cross-linked structure,Weight average molecular weight is 1.1 million~ 10 millionStyrene polymer sulfonated products and / or salts thereofAnd the sulfonic acid group content is 30 mol% or more based on the aromatic.When a sludge dewatering agent is used and this and a cationic polymer flocculant and / or an inorganic flocculant are sequentially added to the sludge, flocs having a low water content are generated. When the sludge generated by this floc is filtered, the sludge is filtered at a high filtration rate and separated into a sludge cake having a low turbidity and a sludge cake having a low water content. The cake thus produced can be easily peeled off from the filter cloth and can be incinerated with a small amount of fuel used because of its low water content. Therefore, sludge is processed efficiently.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of the present invention will be described.
[0011]
The sludge dehydrating agent of the present invention contains a sulfonated styrene polymer having a weight average molecular weight of 1.1 million or more and / or a salt thereof. The sulfonated polymer and / or salt thereof acts as a so-called anionic polymer flocculant, and is added to the sludge as it is, or the polymer flocculant and / or inorganic flocculant is added to the sludge. It is added after the addition.
[0012]
The styrene polymer sulfonated product and / or salt thereof may be a sulfonated polymer of styrene homopolymer and / or a salt thereof, and a sulfonated product of a copolymer of styrene and a monomer copolymerizable with the styrene. And / or a salt thereof.
[0013]
Monomers copolymerizable with styrene include aromatic monomers such as α-methylstyrene, vinyl toluene and vinyl naphthalene, conjugated dienes such as butadiene, isoprene, pentadiene and cyclopentadiene, and olefins such as ethylene, propylene, butene and isobutylene. Nitrile group-containing monomers such as acrylic acid, methacrylic acid, maleic acid, fumaric acid, crotonic acid, itaconic acid, citraconic acid or esters thereof, and acrylonitrile. These monomers may be copolymerized alone with styrene or two or more with styrene. However, the content of these other monomers is preferably 50 mol% or less, and preferably 2 to 40 mol%.
[0014]
Further, such a styrene polymer sulfonated product and / or a salt thereof preferably has a three-dimensional structure such as a crosslinked structure in order to increase the aggregation effect.
[0015]
As a method of producing a styrene polymer sulfonated product and / or a salt thereof having a crosslinked structure, (a) a method of positively forming a sulfone bridge when sulfonated a styrene polymer, (b) a styrene type In the polymerization reaction for obtaining a polymer, there is a method in which a crosslinkable monomer such as divinylbenzene is added to obtain a crosslinked styrene-based polymer, which is sulfonated.
[0016]
Among these, in the case of the method (a), specifically, a condition is used in which a styrene polymer is dissolved in a solvent at a concentration of 0.2 to 40% by weight and sulfonated with a sulfonating agent such as sulfuric anhydride. It is done.
[0017]
The styrenic polymer used here is waste (waste material) discharged from factories, dealers, homes, etc. even if it is newly synthesized (virgin material) to produce a sludge dewatering agent. Alternatively, the virgin material and the waste material may be used in combination. From the viewpoint of preserving the global environment, it is desirable to actively use waste materials rather than virgin materials.
[0018]
When using waste materials, the styrenic polymer may be an alloy with other polymers, and various additions such as facial dyes, stabilizers, flame retardants, plasticizers, fillers, and other auxiliary agents. An agent may be included.
[0019]
In addition, other polymers may be mixed in the styrene polymer. Examples of the polymer that can be mixed include polyacrylonitrile, polyphenylene ether, polycarbonate, polyphenylene sulfide, polyethylene terephthalate, polybutylene terephthalate, polyamide, polyethylene, polypropylene, PVC (polyvinyl chloride), and polybutadiene. However, the mixing amount of these polymers is desirably 60% by weight or less. When the mixing amount of the other polymer is more than 60% by weight, introduction of the sulfonic acid group is inhibited.
[0020]
In the case of the sulfonated styrene copolymer and / or salt thereof obtained by the method (a), the weight average molecular weight (Mw-S) of the sulfonated styrene polymer and the weight of the styrene polymer before sulfonation. The ratio (Mw-S) / (Mw-P) of the average molecular weight (Mw-P) is an index of the degree of crosslinking, and the larger the ratio, the more sulfone bridges are formed.
[0021]
As a styrene polymer sulfonated product and / or a salt thereof used as a sludge dehydrating agent, the value of (Mw-S) / (Mw-P) is preferably 4.5 to 20.0. When the value of (Mw-S) / (Mw-P) is smaller than 4.5, the molecular spread is insufficient and the aggregation effect is not sufficiently exhibited. On the other hand, if the value of (Mw−S) / (Mw−P) exceeds 20.0, the solubility in water becomes low, and a sufficient coagulation effect cannot be obtained.
[0022]
In the method (b), specifically, a crosslinkable monomer such as divinylbenzene is added at the time of polymerization between styrene monomers or copolymerization of a styrene monomer and another monomer, radical polymerization, cationic polymerization, A crosslinked styrene-based polymer is produced by anionic polymerization, and this is sulfonated by a conventional method.
[0023]
It is preferable that the addition amount of this crosslinkable monomer is 0.01 to 10 mol% with respect to the styrene monomer. When the addition amount of the crosslinkable monomer is less than 0.01 mol%, the degree of crosslinking of the resulting polymer becomes insufficient, and the aggregation effect cannot be sufficiently improved. On the other hand, if the addition amount of the crosslinkable monomer exceeds 10 mol%, the sulfonated polymer and / or salt thereof becomes insoluble in water and the aggregation effect is not sufficiently exhibited.
[0024]
The styrene polymer sulfonated salt may be obtained by neutralizing the styrene polymer sulfonated product synthesized as described above with an alkali, and is a homopolymer of styrene sulfonate. Further, it may be a copolymer of a styrene sulfonate and a monomer copolymerizable with the styrene sulfonate.
[0025]
Monomers copolymerizable with styrene sulfonate include acrylic acid or salts thereof, vinyl sulfonic acid salts, allyl sulfonic acid salts, methallyl sulfonic acid salts, 2-acrylamido-2-phenylpropane sulfonic acid salts , 2-acrylamido-2-methylpropanesulfonic acid salts, (meth) acrylamide. These monomers may be copolymerized alone with styrene sulfonate or two or more with styrene sulfonate. However, the content of these other monomers is preferably 50 mol% or less, and preferably 2 to 40 mol%.
[0026]
The copolymer of styrene sulfonate and these monomers also preferably has a three-dimensional structure such as a crosslinked structure in order to increase the aggregation effect.
[0027]
In order to form a cross-linked structure, the cross-linkable monomer may be added in an amount of 0.01 to 10 mol% when the styrene sulfonate and these monomers are subjected to a polymerization reaction.
[0028]
Crosslinkable monomers include methylene bisacrylamide, methylene bismethacrylamide, hexamethylene bisacrylamide, hexamethylene bismethacrylamide, ethylene glycol diacrylate, ethylene glycol dimethacrylate, polyethylene glycol diacrylate, polyethylene glycol dimethacrylate, adipic acid Divinyl, allyl acrylate, allyl methacrylate, N, N-diallylacrylamide, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate and the like are used.
[0029]
In the styrene polymer sulfonated salt, examples of the salt include alkali metal salts, alkaline earth metal salts, ammonium salts, amine salts and quaternary ammonium salts.
[0030]
Examples of the alkali metal ion forming the alkali metal salt include lithium, sodium and potassium ions.
[0031]
Examples of the alkaline earth metal ion forming the alkaline earth metal salt include magnesium and calcium ions.
[0032]
Examples of amines that form amine salts include trimethylamine, triethylamine, tributylamine, diethylamine, dibutylamine, alkylamines such as butylamine, arylamines such as aniline and benzylamine, triethanolamine, diethanolamine, monoethanolamine, and monoethanoldimethylamine. And alkanolamines.
[0033]
Examples of the quaternary ammonium compound of the quaternary ammonium salt include hydroxytetraalkyl (aryl) ammonium such as hydroxytetraethylammonium, hydroxytrimethylethylammonium, hydroxytetramethylammonium, and hydroxytrimethylbenzylammonium.
[0034]
Of these salts, alkali metal salts are preferred, and sodium salts are most preferred. In addition, in the salt of the styrene polymer sulfonated product, one kind of these ions may be contained, or two or more kinds may be contained.
[0035]
Such a styrene polymer sulfonated product and / or a salt thereof preferably has a sulfonic acid group content of 30 mol% or more based on the aromatic nucleus. If the content of the sulfonic acid group is less than this, the water-solubility is not exhibited, and the dehydration effect is greatly reduced.
[0036]
The weight average molecular weight of the sulfonated polymer and / or salt thereof is preferably 1.1 million to 10 million, more preferably 1.2 million to 10 million. When the weight average molecular weight is less than 1,100,000, the electrostatic adsorptive power to cations in sludge decreases, so the moisture content of floc, the filtration speed during sludge dewatering, the peelability of dewatered cake, and the cleanliness of the filtrate Dehydration performance regarding (turbidity) etc. cannot be obtained sufficiently. On the other hand, when the weight average molecular weight exceeds 10 million, the handleability of the sludge dehydrating agent is deteriorated.
[0037]
The styrene polymer sulfonated product and / or its salt as described above is used in combination with a cationic polymer flocculant and / or an inorganic flocculant.
[0038]
Examples of the cationic polymer flocculant include the following.
[0039]
(1) A quaternized product of dialkylaminoalkyl acrylate or dialkylaminoalkyl methacrylate (as a quaternizing agent, methyl chloride, dimethyl sulfate, benzyl chloride, etc.) or an acid salt thereof (as an acid salt, hydrochloride, sulfate) Polymers of inorganic acid salts and organic acid salts such as acetate, etc., or copolymers of these with acrylamide or methacrylamide (for example, polymers of methyl chloride quaternized products of dimethylaminoethyl acrylate, or the like) And acrylamide copolymer)
(2) Dialkylaminoalkylacrylamide or a quaternized product of dialkylaminoalkylmethacrylamide or a polymer thereof, or a copolymer thereof with acrylamide or methacrylamide (for example, a methyl chloride quaternized product of dimethylaminopropylacrylamide) And acrylamide copolymer)
(3) Cationic modified products of polyacrylamide (for example, Mannich modified products of polyacrylamide and Hoffman degradation products)
(4) Epihalohydrin-amine condensate (for example, polycondensate of epihalohydrin and C2-6 alkylenediamine)
(5) Polyvinylimidazoline and its quaternized product or acid salt
(6) Polydimethyldiallylammonium chloride
(7) Dicyandiamide condensate (for example, formalin condensate of dicyandiamide and ammonium chloride)
(8) Polyethyleneimine and its quaternized product or acid salt
(9) Polyvinylimidazole and its quaternized products or acid salts
(10) Poly-4-vinylbenzyltrimethylammonium chloride
(11) Chitosan and its salts
(12) An acidic hydrolyzate of N-vinylformamide / acrylonitrile copolymer and its quaternized product or acid salt
(13) Polyvinylpyridine and its quaternized product or acid salt
(14) Water-soluble aniline resin and its quaternized product or acid salt
(15) Condensate of alkylene dichloride and polyalkylene polyamine
(16) Aniline-formaldehyde polycondensate salt
(17) Polyhexamethylene thiourea acetate
(18) Polyamino acids (for example, polylysine, polyglutamic acid and salts thereof) and the like can be mentioned.
[0040]
Of these, preferred are quaternized dialkylaminoalkyl acrylate or dialkylaminoalkyl methacrylate polymers or their acid salts, or copolymers thereof with acrylamide or methacrylamide, and dialkylaminoalkyl acrylamide or dialkylamino. Alkylmethacrylamide quaternary compounds or their acid salt polymers, or copolymers thereof with acrylamide or methacrylamide, particularly preferred are dialkylaminoalkyl acrylates or quaternary compounds of dialkylaminoalkyl methacrylates or It is a polymer of the acid salt, or a copolymer of these with acrylamide or methacrylamide.
[0041]
Examples of inorganic flocculants include aluminum sulfate, polyaluminum chloride, sodium aluminate, ferrous sulfate, ferric chloride, ferric sulfate, copper chloride, modified basic aluminum sulfate (LACS), and active silica. Can be mentioned.
[0042]
These cationic polymer flocculants and inorganic flocculants can be used alone, or two or more cationic polymer flocculants may be combined, or two or more inorganic flocculants may be combined. Further, a cationic polymer flocculant and an inorganic flocculant may be used in combination.
[0043]
In order to treat sludge by combining a sulfonated styrene polymer and / or a salt thereof with a cationic polymer flocculant and an inorganic flocculant as described above, these compounds are first added to the sludge. Flocculates suspended material to produce floc.
[0044]
The sludge to be treated here has a negative zeta potential and is charged to a negative charge, and is mainly organic sludge. The sludge may contain an inorganic substance. For example, surplus sludge in activated sludge treatment of sewage, sewage and other various sewage, first sedimentation basin sludge of sewage, sewage septic tank sludge, and these aerobic or anaerobic digested sludge, pulp and paper industry wastewater, oil-containing wastewater, dyeing wastewater, etc. Examples include coagulated sediment sludge, coagulated sludge generated by tertiary treatment such as sewage and manure. These sludges are treated alone or mixed.
[0045]
When adding a styrene polymer sulfonated product and / or a salt thereof, and a cationic polymer flocculant or an inorganic flocculant to such sludge, it is desirable to add them separately and sequentially.
[0046]
As a method of addition, after adding and stirring a styrene polymer sulfonated product and / or a salt thereof, adding a cationic polymer flocculant or an inorganic flocculant, stirring and aggregating, There are two methods of adding a cationic polymer flocculant or an inorganic flocculant and stirring to agglomerate, then adding a styrene polymer sulfonated product and / or a salt thereof and stirring to agglomerate. Is more common.
[0047]
The method for adding these compounds to sludge may be a method in which compounds are directly added to sludge, or a method in which compounds are dissolved or mixed in water and added to sludge.
[0048]
The amount of each compound added depends on the type of sludge, the concentration of the suspension in the sludge, and the dehydration equipment, but is generally 0.01 to 1000 ppm (vs. wastewater), preferably 0.1 to 500 ppm (vs. Wastewater) is appropriate. If the amount added is small, sufficient dehydration effect cannot be obtained. Further, even if the amount added exceeds the above range, no further aggregation effect can be obtained, and the compound is wasted. Usually, the cationic flocculant is added in an amount of from 1 to 100 times the amount of the sulfonated styrene polymer and / or salt thereof.
[0049]
When this sludge is aggregated, nonionic or anionic polymer flocculants, coagulants, chelating resins, chelating agents, activated carbon, ozone water, ion exchange resins and ion exchange membranes, water absorbent resins, hydrogen peroxide water Chlorine and liquid chlorine, sodium hypochlorite, chlorine dioxide, bleached powder, chlorinated isocyanuric, diatomaceous earth, photocatalysts such as titanium oxide, and various sub-treatment agents such as biological treatment agents may be used in combination.
[0050]
After the suspension is aggregated by adding the compound in this manner, the aggregate is dehydrated. As the dehydrator, any conventionally used dehydrator such as a belt press dehydrator, a filter press dehydrator, a centrifugal dehydrator, a screw press, etc. can be used. In particular, when the present invention is used, the belt press dehydrator is used. The moisture content of the cake formed in is reduced, and the peelability between the cake and the filter cloth is improved.
[0051]
The cake dehydrated by these dehydrators is subjected to incineration or landfill processing by a known method. In addition, it is very easy to make fuel and compost.
[0052]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to this.
[0053]
First, a styrene polymer sulfonated product having a molecular weight of 1.1 million or more and / or a salt thereof (polymer 1 to polymer 9) used in this example, a comparative polymer 1 to a comparative weight for comparison with this. The combined polymer 5 and the cationic polymer flocculant and inorganic flocculant used in combination with these are shown below.
[0054]
Polymer 1
The polymer 1 is a polystyrene sulfonic acid Na salt having a weight average molecular weight of 1,500,000 and a sulfonic acid group introduction rate with respect to styrene units of 100 mol%.
[0055]
This Na salt of polystyrene sulfonic acid was synthesized as follows.
[0056]
First, 100 parts by weight of commercially available GP grade polystyrene (weight average molecular weight Mw: 200,000) was dissolved in 2000 parts by weight of chloroform to prepare a raw material solution. And this raw material solution was continuously supplied with the sulfuric acid anhydride (SO3) which is a sulfonating agent to the sulfonation reactor with a turbine type stirrer, and sulfonation reaction was performed at the temperature of 45 degreeC. The supply rate of the liquid agent was 80 g / min for the raw material solution, 3.38 g / min for sulfuric anhydride, and the molar ratio of SO3 to styrene units of polystyrene (SO3 / styrene units) was 1.10. A reactor with a jacket having a capacity of 400 ml was used as the reactor.
[0057]
And after distilling chloroform off from the obtained reaction mixture, a polystyrene sulfonated product was obtained, and then neutralized with an aqueous sodium hydroxide solution to produce Na salt of polystyrene sulfonic acid. This Na salt of polystyrene sulfonic acid had a weight average molecular weight of 1,500,000 and a sulfonic acid group introduction rate with respect to styrene units was 100 mol%.
[0058]
Polymer 2
Polymer 2 is an Na salt of polystyrene sulfonic acid having a weight average molecular weight of 1,600,000 and a sulfonic acid group introduction rate with respect to styrene units of 100 mol%.
[0059]
This Na salt of polystyrene sulfonic acid was synthesized as follows using a waste polystyrene foam as a raw material.
[0060]
First, 60 parts by weight of polystyrene foam waste (polystyrene having a weight average molecular weight Mw of 210,000) was dissolved in 2000 parts by weight of 1,2-dichloroethane to prepare a raw material solution. Then, this raw material solution is mixed with sulfuric anhydride (SO_Three) And a sulfonation reactor equipped with a turbine-type stirrer, and the sulfonation reaction was carried out at a temperature of 45 ° C. The feed rate of this liquid agent was 80 g / min for the raw material solution and 2.12 g / min for sulfuric anhydride, and the molar ratio of SO3 to styrene units in the polystyrene (SO3 / styrene units) was 1.15. A reactor with a jacket having a capacity of 400 ml was used as the reactor.
[0061]
Then, 1,2-dichloroethane was distilled off from the obtained reaction mixture to obtain a polystyrene sulfonated product, and then neutralized with an aqueous sodium hydroxide solution to produce an Na salt of polystyrene sulfonic acid. This polystyrene sulfonic acid Na salt had a weight average molecular weight of 1,600,000 and a sulfonic acid group introduction rate with respect to styrene units of 100 mol%.
[0062]
Polymer 3
The polymer 3 is a polystyrene sulfonic acid Na salt having a weight average molecular weight of 3 million and a sulfonic acid group introduction rate of 90 mol% with respect to styrene units.
[0063]
This Na salt of polystyrene sulfonic acid is the same raw material as in the case of polymer 2, except that TV housing waste (mainly polystyrene having a weight average molecular weight Mw of 180,000 and containing 5 mol% of polybutadiene) is used instead of expanded polystyrene. It produced | generated by performing preparation of a solution, sulfonation, evaporation of a solvent, and neutralization by sodium hydroxide aqueous solution.
[0064]
Polymer 4
Polymer 4 is a K salt of a sulfonated styrene-isoprene copolymer having a weight average molecular weight of 1,100,000 and a sulfonic acid group introduction rate with respect to styrene units of 60 mol%.
[0065]
The K salt of the sulfonated product of styrene-isoprene copolymer was synthesized as follows.
[0066]
First, a mixture of 140 parts by weight of styrene, 60 parts by weight of isoprene, 5 parts by weight of 1,4-dioxane and 3800 parts by weight of cyclohexane was put into an autoclave reactor, and the inside of the reactor was purged with nitrogen. Thereafter, 0.7 ml of a hexane solution in which 1.6 mol / l of n-butyllithium was dissolved was added to this mixture, and a polymerization reaction was performed for 5 hours. It was 180,000 when the molecular weight was measured by GPC about the obtained polymer.
[0067]
Next, the obtained polymer solution was poured into a glass reactor, and sulfuric acid as a sulfonating agent was bubbled into the glass reactor for sulfonation. And after obtaining the sulfonated product of styrene-isoprene copolymer by distilling off the solvent from the obtained reaction mixture, the sulfonated product of styrene-isoprene copolymer sulfonated product is neutralized with an aqueous potassium hydroxide solution. Was generated. This isoprene copolymer sulfonated K salt had a weight average molecular weight of 1,100,000 and a sulfonic acid group introduction rate with respect to styrene units of 60 mol%.
[0068]
Polymer 5
The polymer 5 is a Na salt of a sulfonated product of a styrene-acrylic acid copolymer having a weight average molecular weight of 1.13 million and a sulfonic acid group introduction rate of 95 mol% with respect to styrene units.
[0069]
This Na salt of the sulfonated styrene-acrylic acid copolymer was synthesized as follows.
[0070]
First, a mixture of 160 parts by weight of styrene, 40 parts by weight of acrylic acid, and 1800 parts by weight of 1,2-dichloroethane was put into a reactor, 0.4 parts by weight of benzoyl peroxide was added under a dry nitrogen stream, Stir at 0 ° C. for 3 hours. Further, 0.4 parts by weight of benzoyl peroxide was added and stirred at a temperature of 80 ° C. for 3 hours. Thereafter, the same addition of benzoyl peroxide and stirring were repeated three times to carry out a polymerization reaction. Subsequently, the unreacted monomer was distilled off together with the solvent from the reaction mixture to obtain a styrene-acrylic acid copolymer. It was 250,000 when the molecular weight was measured by GPC about the obtained polymer.
[0071]
The obtained polymer was dissolved in 1,800 parts by weight of 1,2-dichloroethane, and sulfonated, distilled off of the solvent, and neutralized with an aqueous sodium hydroxide solution as in the case of polymer 2, thereby styrene-acrylic acid. A Na salt of a sulfonated copolymer was produced. The obtained Na salt of the sulfonated product of styrene-acrylic acid copolymer had a weight average molecular weight of 1.13 million and a sulfonic acid group introduction rate with respect to styrene units of 95 mol%.
[0072]
Polymer 6
The polymer 6 is an ammonium salt of a crosslinked polystyrene sulfonated product having a weight average molecular weight of 1,500,000 and a sulfonic acid group introduction rate with respect to styrene units of 75 mol%.
[0073]
The ammonium salt of the crosslinked polystyrene sulfonated product was synthesized as follows.
[0074]
First, a mixture of 200 parts by weight of styrene, 1 part by weight of p-divinylbenzene and 1800 parts by weight of cyclohexane was placed in a reactor, and 1 part by weight of azobisisobutyronitrile was added under a dry nitrogen stream, Stir for hours. Further, 1 part by weight of azobisisobutyronitrile was added and stirred at a temperature of 80 ° C. for 3 hours. Thereafter, the same addition of azobisisobutyronitrile and stirring were repeated three times to carry out a polymerization reaction. . Subsequently, the unreacted monomer was distilled off together with the solvent from the reaction mixture to obtain a crosslinked polystyrene. It was 200,000 when the molecular weight was measured by GPC about the obtained polymer.
[0075]
Next, 1800 parts by weight of cyclohexane was added to the resulting polymer, and sulfonation was performed by blowing sulfuric acid as a sulfonating agent in a gaseous state. The solvent was distilled off from the reaction mixture to obtain a sulfonated product of crosslinked polystyrene, and then neutralized with ammonia water to produce an ammonium salt of the sulfonated product of crosslinked polystyrene. The ammonium salt of the sulfonated product of crosslinked polystyrene had a weight average molecular weight of 1,500,000 and a sulfonic acid group introduction rate with respect to styrene units was 75 mol%.
[0076]
Polymer 7
The polymer 7 is a copolymer of Na styrene sulfonate and Na-acrylamide-methylpropane sulfonate, and has a weight average molecular weight of 1.3 million.
[0077]
This copolymer was synthesized as follows.
[0078]
First, after dissolving 100 parts by weight of Na styrene sulfonate and 80 parts by weight of 2-acrylamido-2-methylpropane sulfonate (AMPS) in 720 parts by weight of purified water, 0.45 part by weight of ammonium persulfate and 0% potassium hydrogen sulfite. .23 parts by weight was added and stirred at a temperature of 50 ° C. for 3 hours. Further, 0.45 parts by weight of ammonium persulfate and 0.23 parts by weight of potassium hydrogen sulfite were added and stirred at a temperature of 50 ° C. for 3 hours to obtain a copolymer of AMPS and Na styrenesulfonate. The weight average molecular weight of the obtained copolymer was 1.3 million.
[0079]
Polymer 8
The polymer 8 is a copolymer of Na styrene sulfonate and acrylamide, and has a weight average molecular weight of 2.3 million.
[0080]
This copolymer was synthesized as follows.
[0081]
First, 50 parts by weight of acrylamide, 100 parts by weight of Na styrene sulfonate monomer and 1 part by weight of methylenebismethacrylamide were dissolved in 600 parts by weight of purified water, and then 0.35 parts by weight of ammonium persulfate and 0.18 parts by weight of potassium hydrogen sulfite. And the mixture was stirred at a temperature of 50 ° C. for 3 hours. Further, 0.35 parts by weight of ammonium persulfate and 0.18 parts by weight of potassium hydrogen sulfite were added and stirred at a temperature of 50 ° C. for 3 hours to obtain a copolymer of Na styrene sulfonate and acrylamide. The weight average molecular weight of the obtained copolymer was 2.3 million.
[0082]
Polymer 9
The polymer 9 is polystyrene sulfonic acid having a weight average molecular weight of 1,500,000 and a sulfonic acid group introduction rate with respect to styrene units of 100 mol%.
[0083]
This polystyrene sulfonic acid was synthesized in the same manner as the polymer 1 except that neutralization with an aqueous sodium hydroxide solution was not performed.
[0084]
Comparative polymer 1
The comparative polymer 1 is an Na salt of polystyrene sulfonic acid having a weight average molecular weight of 500,000 and a sulfonic acid group introduction rate with respect to styrene units of 90 mol%.
[0085]
This Na salt of polystyrene sulfonic acid was synthesized as follows using a waste polystyrene foam as a raw material.
[0086]
First, 100 parts by weight of polystyrene foam waste (polystyrene having a weight average molecular weight Mw of 210,000) was dissolved in 2000 parts by weight of 1,2-dichloroethane, 2000 parts by weight of concentrated sulfuric acid was added, and the mixture was stirred at a temperature of 80 ° C. for 3 hours. The reaction mixture was diluted with 3000 parts by weight of water and neutralized with an aqueous sodium hydroxide solution. Next, the reaction mixture was concentrated, and sodium sulfate was removed by a recrystallization method to obtain an Na salt of polystyrene sulfonate. The Na salt of the resulting polystyrene sulfonated product had a weight average molecular weight of 500,000 and a sulfonic acid group introduction rate with respect to styrene units of 90 mol%.
[0087]
Comparative polymer 2
The comparative polymer 2 is a polystyrene sulfonic acid Na salt having a weight average molecular weight of 700,000 and a sulfonic acid group introduction rate with respect to styrene units of 100 mol%.
[0088]
This Na salt of polystyrene sulfonic acid was synthesized as follows using expanded polystyrene as a raw material.
[0089]
First, a raw material solution was prepared by dissolving 100 parts by weight of polystyrene foam waste (polystyrene having a weight average molecular weight Mw of 210,000) in 2000 parts by weight of 1,2-dichloroethane. On the other hand, an anhydrous sulfuric acid / triethyl phosphate complex was prepared by adding 240 parts by weight of anhydrous sulfuric acid dropwise to a solution obtained by adding 273 parts by weight of triethyl phosphoric acid to 3000 parts by weight of 1,2-dichloroethane while stirring under ice cooling. . Then, the raw material solution was added dropwise to the sulfuric anhydride / triethyl phosphate complex solution over 3 hours with stirring under ice-cooling, and the reaction temperature was raised to 25 ° C., followed by stirring for 30 minutes. Went. Subsequently, the obtained reaction mixture was diluted with 3000 parts by weight of water and neutralized with an aqueous sodium hydroxide solution. At this time, since the liquid was separated into an aqueous phase and an organic phase, an Na salt of polystyrene sulfonic acid was generated by concentrating the aqueous phase. This Na salt of polystyrene sulfonic acid had a weight average molecular weight of 700,000, and the sulfonic acid group introduction rate relative to the styrene unit was 100 mol%.
[0090]
Comparative polymer 3
The comparative polymer 3 is an Na salt of polystyrene sulfonic acid having a weight average molecular weight of 500,000.
[0091]
This Na salt of polystyrene sulfonic acid was synthesized as follows.
[0092]
First, after dissolving 100 parts by weight of Na styrene sulfonate monomer in 300 parts by weight of purified water, 1 part by weight of ammonium persulfate and 0.5 part by weight of potassium hydrogen sulfite were added and stirred at a temperature of 50 ° C. for 3 hours. Further, 1 part by weight of ammonium persulfate and 0.5 part by weight of potassium hydrogen sulfite were added to this solution and stirred at a temperature of 50 ° C. for 3 hours to obtain an Na salt of polystyrene sulfonic acid. This polystyrene sulfonic acid Na salt had a weight average molecular weight of 500,000.
[0093]
Comparative polymer 4
The polymer 4 for comparison is polystyrene sulfonate Na salt (Chemco) having a weight average molecular weight Mw of 1,000,000.
[0094]
Comparative polymer 5
The comparative polymer 5 is a commercially available sodium polyacrylate [0.2% aqueous solution viscosity (20 ° C.): 680 cps].
[0095]
Cationic polymer flocculant
As the cationic polymer flocculant, methyl chloride quaternized product (strong cation type) of polydimethylaminoethyl acrylate was used.
[0096]
Inorganic flocculant
Aluminum sulfate was used as the inorganic flocculant.
[0097]
In addition, the weight average molecular weight of the styrene polymer used as a raw material, the weight average molecular weight Mw of the polymer 1 to the polymer 8 and the comparative polymer 1 to the comparative polymer 3, and the introduction amount of the sulfonic acid group are as follows. Measured.
[0098]
<Weight average molecular weight of styrene polymer>
It measured by GPC (gel permeation chromatography) method using the ultraviolet detector (measurement wavelength 266nm). Standard polystyrene was used as the standard substance, and trade names TSK-G4000HXL and trade names G2500HXL manufactured by Tosoh Corporation were used for the columns.
[0099]
<Weight average molecular weight of polymer 1 to polymer 9 (styrene polymer sulfonated product or salt thereof)>
It was measured by the static light scattering method described in “Chemistry and Industry” 60 (12) 487-495 (1986), “Principle and Application of Light Scattering Photometry”.
[0100]
Specifically, a product name RM-102 manufactured by Otsuka Electronics Co., Ltd. was used, and the refractive index at various sample concentrations was determined using a 0.1 M / l aqueous potassium chloride solution as a solvent, and the differential refractive index was calculated.
[0101]
In addition, the product name DLS-600 manufactured by Otsuka Electronics Co., Ltd. was used, and the scattering intensity in the range of θ of 30 to 150 ° at various sample concentrations was measured using a 0.1 M / l aqueous potassium chloride solution as a solvent.
[0102]
The molecular weight was calculated by analyzing the characteristic value measured in this way by a Zimm plot.
[0103]
<Introduction rate of sulfonic acid group of polymer 1 to polymer 9 (sulfonated styrene polymer or salt thereof)>
When the raw material polymer is composed only of aromatic monomer units, the ratio of introduction of sulfonic acid groups per unit aromatic ring from the ratio of carbon atoms and sulfur atoms measured by an element analyzer (trade name EA-1108, manufactured by Carlo Elba) Was calculated. However, when sulfate was contained in the water-soluble polymer, the amount was quantified by ion chromatography, and the amount of sulfur atom of the sulfate was subtracted from the amount of sulfur atom obtained by the element analyzer.
[0104]
Moreover, when the raw material polymer is a copolymer of an aromatic monomer and another monomer, a 1H-NMR spectrum is observed with an NMR analyzer (trade name JNM-EX270 type, manufactured by JEOL Ltd.), and the vicinity of 7.6 ppm is observed. Using the peak intensity (a) and the peak intensity (b) near 8.1 ppm, the sulfonic acid group introduction rate = (b / 2) / (a / 3 + b / 2) × 100.
[0105]
Evaluation of coagulation effect on sludge
The aggregation performance of Polymer 1 to Polymer 8 was evaluated as follows.
[0106]
Sludge collected from a sewage treatment plant (pH: 7.0, suspended matter (SS) concentration: 0.8% by weight) was prepared, and the following jar test was performed.
[0107]
First, after adding 0.4% by weight of a cationic polymer flocculant to the amount of suspended solids in each sludge being stirred by a container with a stirrer (jar tester), the polymer 1 Each of the polymer 8 and the comparative polymer 1 to the comparative polymer 5 was added in an amount of 0.2% by weight based on the amount of the suspended material, and the suspended material was aggregated by stirring. However, the cationic polymer was added to the two sludges in an amount of 0.4% by weight or 0.6% by weight based on the amount of suspended substances, and no subsequent polymer was added.
[0108]
Next, a Nutsche test was performed on each aggregated liquid using a polypropylene filter cloth (trade name: PP26FK) to measure the filtration rate and the turbidity of the filtrate was measured with a transmission turbidimeter. Then, the sludge which became the residue in the case of filtration was pinched | interposed with two filter cloths, and it pressed for 1 minute with the pressing test machine in this pinched state. The moisture content of the obtained sludge was examined for the moisture content of the cake and the peelability to the filter cloth.
[0109]
Table 1 shows the filtration rate, filtrate turbidity, cake peelability, and cake moisture content measured as described above. In Table 1, peelability indicates that the peelability is very good, circle indicates that the peelability is good, and indicates that the peelability is poor.
[0110]
[Table 1]

[0111]
As shown in Table 1, in the case of combining the cationic polymer flocculant and the polymers 1 to 8 which are salts of sulfonated styrene polymer having a molecular weight of 1.1 million or more, the filtration rate is fast, The filtrate turbidity is low, the peelability of the cake is good, and the moisture content of the cake is low. On the other hand, even if it is a salt of a styrene-based polymer sulfonated product, a molecular weight of less than 1.1 million (comparative polymer 1 to comparative polymer 4) or other types of polymers (comparison) When the polymer 5) is used, or when only the cationic polymer flocculant is used, the filtration rate is slow and the filtrate turbidity is high. Moreover, the cake peelability is poor and the moisture content of the cake is high.
[0112]
Therefore, as the polymer used in combination with the cationic polymer flocculant, a styrene polymer sulfonated product or a salt thereof is suitable, and the styrene polymer sulfonated product or a salt thereof has a weight average molecular weight of 110. It turns out that it is necessary to be more than 10,000.
[0113]
Evaluation of coagulation effects on paper mill wastewater.
Paper mill wastewater (pH: 7.5, suspended substance (SS) concentration: 120 ppm) was prepared and dispensed into a plurality of containers.
[0114]
And after adding 400 ppm of inorganic flocculants to the amount of waste water to each waste water, each of polymer 1, polymer 3, polymer 9 and comparative polymer 4, comparative polymer 5 is each amount of waste water After adding 2 ppm, the mixture was allowed to stand, and the sedimentation rate of the suspended particles was measured.
[0115]
Next, each agglomerated liquid was filtered with a polypropylene filter cloth (trade name PP26FK), and the turbidity of the filtrate was measured with a transmission turbidimeter and the COD (chemical oxygen demand) was measured.
[0116]
Then, the sludge which became a residue in the case of filtration was pinched | interposed with two filter cloths, and it squeezed for 1 minute with the pressing test machine in this pinched state, and investigated the moisture content of the obtained sludge cake.
[0117]
Table 2 shows the results of sedimentation rate, supernatant turbidity, COD, and cake moisture content measured as described above.
[0118]
[Table 2]

[0119]
As shown in Table 2, when an inorganic flocculant and a styrene polymer sulfonated product having a molecular weight of 1.1 million or more or a salt thereof, such as polymer 1, polymer 3, and polymer 9, are combined, the sedimentation rate is Fast, low filtrate turbidity and COD, low cake moisture content. On the other hand, even if it is a salt of a styrene polymer sulfonated product, a molecular weight of less than 1.1 million (comparative polymer 4) is used, or another type of polymer (comparative polymer 5) is used. When used, the sedimentation rate is slow, the filtrate turbidity and COD are high, and the cake moisture content is also high.
[0120]
Therefore, as the polymer used in combination with the inorganic flocculant, a styrene polymer sulfonated product or a salt thereof is suitable, and the styrene polymer sulfonated product or a salt thereof has a weight average molecular weight of 1.1 million or more. I found it necessary to be.
[0121]
【The invention's effect】
As apparent from the above description, in the present invention, a styrene polymer sulfonated product having a weight average molecular weight of 1.1 million or more and / or a salt thereof is used as a sludge treatment agent, and this is combined with a cationic polymer flocculant and / or an inorganic material. Since the sludge treatment is performed in combination with the flocculant, a high filtration efficiency can be obtained and the filtrate with low turbidity can be obtained during the filtration of the sludge that has generated floc. Further, the moisture content of the cake produced by the treatment is low, and the cake and the filter cloth can be easily peeled off. Therefore, according to the present invention, it is possible to efficiently treat sludge, and the cake produced by the treatment can be incinerated with a small amount of fuel used, which can greatly contribute to the conservation of the global environment. .

Claims (5)

A styrene polymer sulfonated product having a cross-linked structure and a weight average molecular weight of 1.1 million to 10 million and / or a salt thereof , and the content of sulfonic acid groups is 30 mol% or more based on aromatics. Sludge dehydrating agent characterized by The styrene polymer sulfonated product and / or salt thereof is a styrene polymer sulfonated product and / or salt thereof synthesized by a polymerization reaction of a monomer mixture containing 0.01 to 10 mol% of a crosslinkable monomer. The sludge dewatering agent according to claim 1, wherein   The ratio of the weight average molecular weight of the styrene polymer sulfonated product and / or salt thereof to the weight average molecular weight of the styrene polymer before sulfonation is 4.5 to 20.0. The described sludge dehydrating agent.   The sludge dewatering agent according to claim 1, which is a sulfonated plastic waste material and / or a salt thereof containing a styrene polymer. The sludge is a styrene polymer sulfonated product having a cross-linked structure and a weight average molecular weight of 1.1 million to 10 million and / or a salt thereof , and the content of sulfonic acid group is 30 mol% or more with respect to the aromatic. A sludge dewatering agent and a cationic polymer flocculant and / or an inorganic flocculant are sequentially added to treat the sludge.