JPS591400B2 - Method for producing water treatment chemicals - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a new water treatment agent in which a water-soluble vinyl monomer is graft-polymerized on the surface of carbon materials such as coke, pitch or pitch coke, and in particular to a dewatering agent for sludge. The present invention relates to a method for producing a water treatment agent that exhibits excellent effects as a water treatment agent.

The sludge generated when treating sewage or organic wastewater has poor dewatering properties and contains a large amount of water, so even incineration requires a large amount of energy. It is necessary to remove this, and various organic flocculants are being researched and manufactured.

Examples of organic flocculants include polyacrylamide, polyethylene oxide, sodium polyacrylate, polyacrylamide partial hydrolyzate, polyaminoalkyl (meth)acrylate, polydiallylammonium halide, and chitosan. It is used as appropriate.

However, although these organic flocculants are excellent in flocculating sludge, the flocs tend to collapse during the subsequent offshore filtration treatment, causing clogging of the sludge material, and in fact, sufficient filtration cannot be achieved with organic flocculants alone. , it is not easy to improve the dehydration rate.

Therefore, in recent years, a method of graft polymerizing these organic flocculants to coal has been proposed in order to improve the drawbacks of the above-mentioned organic flocculants.

Compared to conventional organic flocculants, this organic flocculant grafted onto coal has a polymer grafted onto the coal as a core, so the sedimentation rate after flocculation is faster than that of the organic flocculant alone. The dewatering properties are also quite excellent, and it can be said that there are some that are particularly excellent when incinerating sludge cake.

However, it is actually extremely difficult to efficiently produce a coal graft polymer with excellent cohesiveness and dehydration properties, that is, one in which a polymer is completely grafted onto coal.

That is, simply adding pulverized coal to an aqueous polymerizable monomer solution does not increase the graft polymerization rate, that is, the ratio of the amount of polymer grafted to coal to the amount of monomer charged.

Therefore, various graft polymerization methods have been proposed to increase the graft polymerization rate.

For example, ■ Mechanical treatment method, that is, a method in which a polymerizable monomer is grafted onto the surface of coal while pulverizing it; ■ Method using a catalyst; ■ Radiation method, that is, a method in which pulverized coal alone is irradiated with radiation in advance, or a method in which pulverized coal and polymerizable There are methods such as irradiating radiation in coexistence with monomers.

However, in the case of method (2), although the graft polymerization rate is improved, on the other hand, a decrease in molecular weight is inevitable due to the intense grinding energy, making it impossible to produce a water treatment agent with excellent cohesion and dehydration properties.

Furthermore, according to the method (2), generally more homopolymers are produced and the polymerization rate of monomers is improved, but the graft polymerization rate is not improved so much.

Furthermore, method (2) is highly dangerous because it involves the use of radiation, and also requires high equipment costs from an industrial perspective.

Therefore, the present inventors have attempted to industrially easily and efficiently produce a graft polymer with better cohesiveness and better dewatering properties without sacrificing the above-mentioned advantages of the coal graft polymer as a dehydrating agent for sludge. As a result of continuing exploratory research on various grafting base materials for grafting, we found that when coke, pitch, or pitch coke is used as a grafting base material, it is possible to simply use these without adopting methods to increase the graft polymerization rate as described above. The present invention was completed based on the discovery that a water treatment agent with excellent dehydration properties that can be grafted at a high ratio can be obtained by simply adding it to an aqueous solution of polymerizable monomers.

That is, the present invention relates to a method for producing a water treatment agent, which comprises graft polymerizing a water-soluble vinyl monomer to one or more powders selected from coke, pitch, and pitch coke of 50 mesh or less. .

As the graft base material used in the present invention, coke, various pitches obtained when distilling tar obtained by carbonization of coal, wood, etc., such as tar pitch, wood cool pitch, etc., can be used. Examples include pitch coke obtained by carbonizing pitch.

There is no problem even if one or more of these are used as a mixture.

It is desirable to use these materials after pulverizing them, and the degree of pulverization is approximately 50 mesh or less, preferably 200 mesh or less.

Above the upper limit, the graft polymerization rate will not improve.

What is particularly important in the present invention is that the graft polymerization rate can be greatly increased by simply mixing these graft base materials with the water-soluble vinyl monomer aqueous solution described below.

2c: Unlike coal, the grafting base material of the present invention has the first point that the grafting performance after pulverization hardly deteriorates.

The graft polymer of the present invention can be produced industrially at low cost, and the obtained graft polymer exhibits excellent effects as a water treatment agent, especially as a sludge dehydrating agent.

The effects of this invention will now be specifically explained as follows.

Specific Example 1 60 g of acrylamide and 40 g of ion-exchanged water were placed in a reaction vessel having a content of 500 rfLl and equipped with a stirrer, a nitrogen inlet tube, and a thermometer, and dissolved with stirring while purging with nitrogen, and the liquid temperature was set at 80°C.

Next, 100 g each of coke, tar pitch, and pitch coke having a weight of 300 mt or less that had been crushed immediately after crushing or that had been crushed and left for 14 days were added, stirred, and then polymerized for 8 hours.

This polymer was thoroughly washed with water at 60°C and dried under reduced pressure to obtain each graft polymer.

Incidentally, as a comparative example, graft polymers were produced in the same manner as described above, using instead of tar pitch, coal of 300 Metsuyu or less immediately after pulverization and coal that had been pulverized and left for 14 days.

The results are shown in Table 1.

As shown in the table above, the graft polymerization rate of coal is considerably lower than that of the coke, pitch or pitch coke of the present invention, and in fact, with such a simple production method, the coal graft polymer cannot be produced industrially. cannot be manufactured, and even if it were manufactured, it would be necessary to use it in a larger amount than the water treatment agent of the present invention in order to impart the dehydration properties of the present invention.

Moreover, although the reason is not clear, the surface activity of coal significantly decreases after pulverization, and the graft polymerization rate reaches zero in about 2 to 4 weeks, whereas the base material of the present invention has this tendency. From this point of view, it can be said that the industrial advantage is significant.

Examples of the water-soluble vinyl hexamer that can be used in the present invention include acrylic acid, methacrylic acid, or ester compounds thereof, acrylamide, methacrylamide, aminocarboxylic acid esters, etc. In particular, the graft base material of the present invention In the case of acrylamide and the following (I)
or an aminocarboxylic acid ester represented by the formula (...) (in the formula, R1 is H or CH3, R2 is H or has 1 carbon number)
~4 alkyl group, R3 and R4 are alkyl groups having 1 to 4 carbon atoms, n2 is an integer of 1 to 4, and X represents an anion group.

) For example, dimethylamine ethyl (meth)acrylate, diethylamine ethyl (meth)acrylate, tertiary salts thereof such as hydrochloride, sulfate, acetate, and tertiary salts quaternized with methyl chloride, dimethyl sulfate, or diethyl sulfate. By co-using quaternary salts and the like, it is possible to further increase the graft polymerization rate and provide a chemical with excellent water treatment effects.

Now, this effect can be demonstrated as follows.

Specific Example 2 Into a reaction vessel with a capacity of 300 ml and equipped with a stirrer, a nitrogen inlet tube, and a thermometer, the predetermined amounts of acrylamide and dimethylamine ethyl methacrylate methyl chloride salt shown in Table 2 were placed, and 27 g of ion-exchanged water was added. The solution was stirred and dissolved while purging with nitrogen, and the liquid temperature was set at 60°C.

Next, 67 g of coke of 200 mesh or less was added,
After stirring, polymerization was carried out for 10 hours.

The resulting graft polymer was thoroughly washed with water at 60° C., dried under reduced pressure, and then the graft polymerization rate was determined.

Next, using these graft polymers, the dewaterability of activated surplus sludge (suspended solid content 1.8 weight ratio, pH 7, 6) was tested.

500 Tnl of the above sludge was taken into a beaker, and to this suspended solid content, suspension water was added in proportion to 2 parts by weight of the graft polymer so that the proportion was 1.5 parts by weight in terms of the polymer in the graft polymer, and water was added. After making the total volume 600ml, 2
After stirring for 10 minutes at 0Or-'p0m, a Nutsche test was conducted under the conditions shown below.

[Nutsche test conditions]

Decompression degree 400wnHg Offshore area 95ffl Oki Material Toyo P paper A5A The results are shown in Table 2.

As is clear from the above, in the present invention, the graft polymerization rate can be further increased by using dimethylaminoethyl methacrylate methyl chloride salt, which is a type of aminocarboxylic acid ester, rather than using acrylamide alone.

However, in the case of a single aminocarboxylic acid ester, although the graft polymerization rate can be approximately 100%, the dewaterability, that is, the sludge flow rate tends to decrease. When used in a ratio of 9:1 to 1:9 (weight ratio), the effects of the present invention can be further enhanced.

Regarding the manufacturing conditions for the water treatment agent of the present invention, the monomer concentration varies depending on the type of monomer, but is generally in the range of 20 to 90% by weight.

Although there are no restrictions on the amount of the graft base material used in the present invention, the degree of polymerization generally decreases as the ratio of the graft base material added to the monomer increases.

The reaction temperature is preferably 20 to 80°C.

The polymerization time varies depending on the type of monomer, the degree of pulverization of the graft base material, and the manufacturing conditions, but approximately 3 to 12 hours is sufficient.

In the present invention, it is possible to obtain a polymer with a high graft polymerization rate by simply mixing coke or the like with a water-soluble vinyl monomer, but in order to further speed up the polymerization rate or take into account the use of existing equipment, a catalyst, It cannot prevent the use of ultraviolet rays and radiation during polymerization.

Further questions will be asked below with reference to examples of the present invention.

Example 1 Acrylamide 20.0 mm was placed in a reaction vessel with a capacity of 500 ml and equipped with a stirrer, a nitrogen inlet tube, and a thermometer. After taking 59.7 g of F11 diethylamine ethyl methacrylate and 20 g of ion-exchanged water and adjusting the pH to 2.8 with 10% hydrochloric acid,
The mixture was stirred and dissolved while purging with nitrogen, and the liquid temperature was set at 50°C.

Next, 80.2 g of tar pitch of 150 meshes or less was added, stirred, and then polymerized for 5 hours.

This polymer was thoroughly washed with water at 60°C and dried under reduced pressure to obtain graft polymer 164.8I.

When 17rnl of this graft polymer 2 weight suspension was added to 5001nl of activated surplus sludge used in Example 2 and a dewatering property test was conducted, the flow rate was 5.2kl/t.
ri: It was hr.

Example 2 30% of an 80% sodium acrylate aqueous solution was placed in a reaction vessel with a content capacity of 300 WLl equipped with a stirrer, a nitrogen inlet tube, and a thermometer.
．． 0g and 30.0g of ion-exchanged water were taken, and the liquid temperature was set at 70°C while replacing with nitrogen.

Next, pitch coke 96, (B
i' was added, stirred, and then polymerized for 10 hours.

This polymer was thoroughly washed with water at 60°C and dried under reduced pressure to obtain graft polymer 114. Hi' was obtained.

This graft polymer and polyaluminum chloride (A120
3102%, basicity 50.3%) was used to treat fishery processing wastewater (pH 7.3, suspended solid content 53 ppm).

Polysalt aluminum 2 to 500WLl of the above seafood processing wastewater
After adding 00p- and mixing for 2 minutes, 5 ml of the above graft polymer double hereditary suspension was added and mixed.

Next, the generated flocs are separated by sedimentation to reduce the suspended solid content5.
6 Lord's treated water was obtained.

As a comparative example, a polymer flocculant (molecular weight 3 million) manufactured using sodium acrylate instead of the graft polymer and pitch coke were mixed with the water treatment agent of the present invention in a four weight ratio, that is,
As a result of the same test using a ratio of 1:5, treated water with a suspended solid content of 34.21'l'' was obtained.

Example 3 35.6 g of acrylamide was placed in the reaction vessel used in Example 2.
19.2 g of 80% sodium acrylate aqueous solution and 47.1 g of ion-exchanged water were taken and dissolved with stirring while purging with nitrogen, and the liquid temperature was set at 60°C.

Next, 72.0 g of coke of 300 mesh or less was added, stirred, and then polymerized for 6 hours.

This polymer was thoroughly washed with water at 60°C and dried under reduced pressure to obtain graft polymer 111. :l was obtained.

This graft polymer and polyaluminum chloride (A120
310.1%, basicity 50.2%) was used to treat oil-containing wastewater (oil content 164 ppm, suspended solid content 78 pp).

Polyaluminum chloride 300 in the above wastewater 5007711
After adding the solution and mixing for 2 minutes, 3 ml of the above-mentioned single-layer graft polymer suspension was further added and mixed.

The generated scum was then removed to obtain treated water with an oil content of 5 ppm and a suspended solid content of 4.31) In.

As a comparative example, a polymer flocculant (molecular weight 9.6 million, anionization rate 24.5%) manufactured using acrylamide and sodium acrylate instead of the graft polymer and coke were mixed with the water treatment agent of the present invention in a four weight ratio. That is, when used together in a ratio of 1:2 and tested in the same manner, the oil content was 18% and the suspended solid content was 1%.
Treated water with a concentration of 8.7 ppm was obtained.

Example 4 Acrylamide 20, 5 was added to the reaction vessel used in Example 2.
g, dimethylamine ethyl acrylate methyl chloride salt 5
9.7 g and 20 g of ion-exchanged water were taken and dissolved with stirring while purging with nitrogen, and the liquid temperature was set at 70°C.

Next, 52.7 g of tar pitch of 200 meters or less was added, stirred, and then polymerized for 8 hours.

This polymer was thoroughly washed with water at 60° C. and dried under reduced pressure to obtain 128.4 g of a graft polymer.

When 201 rLl of this graft polymer single hereditary suspension was added to 500 ml of activated surplus sludge used in Example 2 and a dewatering property test was conducted, the offshore overspeed was 4.8 kl/m.
・It was hr.

As a comparative example, a polymer flocculant (cationization rate: 517) produced using acrylamide and dimethylamine ethyl acrylate methyl chloride salt instead of the graft complex and tar pitch were mixed with the water treatment agent of the present invention in a four weight ratio, that is, 3:
When used together at a ratio of 2, it is 0.8 kl/lri
'・hr.

Example 5 A flocculation test using kaolin suspension water was conducted using the graft polymer manufactured in Example 3 (invention product) and the polymer flocculant manufactured using acrylamide and sodium acrylate (comparative example product). .

Add and suspend pharmacopoeial kaolinite to tap water, pH 71,
Turbid water with a turbidity of 353 degrees was prepared.

Take 500 ml of this, add a predetermined amount of 1-fold hereditary suspension of the above-mentioned drug (inventive product, comparative example product), and stir rapidly for 1 minute at 150 ml using a jar tester.
After performing slow stirring for 3 minutes with Qrpl, the sedimentation rate of the flocs and the turbidity of the supernatant water after standing for 5 minutes were measured.

The results are shown in Table 3.

Claims (1)

[Scope of Claims] A method for producing a water treatment agent, which comprises graft polymerizing a water-soluble vinyl monomer to one or more powders selected from coke, pitch, and pitch coke having a mesh size of 150 mesh or less. 2. The method for producing a water treatment agent according to claim 1, wherein acrylamide and an aminocarboxylic acid ester represented by the following formula (1) or (1) are used together as the water-soluble vinyl monomer. (In the formula, R1 is H or CH3, R2 is -H or an alkyl group having 1 to 4 carbon atoms, R3 and R4 are an alkyl group having 1 to 4 carbon atoms, n is an integer of 1 to 4, and X is an anion group. )