JP2510122B2 - Method for treating waste liquid containing acrylic acid ester or methacrylic acid ester - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to porous objects, especially castings,
Waste liquid generated when impregnating an object such as a sintered metal or wood or an inorganic object such as rock, brick or concrete with an acrylic ester or a methacrylic ester (hereinafter referred to as (meth) acrylic ester). Treatment of a waste liquid containing a (meth) acrylic acid ester, in which a water-insoluble polymer is hardened into a granular form in a solution to be treated to facilitate separation after the treatment and a COD value of the treatment solution is lowered. Regarding the method.

[0002]

2. Description of the Related Art It is common practice to impregnate pores in a porous body, particularly a body such as a casting, a sintered metal, or wood, with a (meth) acrylic acid ester for sealing.
This is necessary to improve the corrosion resistance or pressure resistance of these materials against gas or liquid, or to increase the density and strength to improve the product yield.

A general impregnation treatment method is to wash an object to be treated with a suitable solvent first, put the object to be treated in a tank, and then to evacuate the tank to obtain air and pretreatment from pores to be filled. After evaporating the solvent, the liquid to be impregnated is introduced into the tank, followed by pressurization with an air pressure of several kg / cm ^{2 in} order to accelerate the permeation of the liquid. Next, the impregnated object to be treated is taken out from the tank, the excess liquid adhering to the surface is collected, and then the surface is cleaned in a plurality of cleaning tanks. Finally, it is left in hot water or hot air for several minutes to several hours in order to cure the liquid that has penetrated into the object to be treated. The COD value of the waste liquid generated from the cleaning process of the impregnation is tens of thousands ppm.
Generally, the industrial waste treatment company is entrusted with the treatment as industrial waste, or it is diluted with fresh water and then treated at an integrated wastewater treatment facility incorporating the activated sludge method. However, in order to process as industrial waste, a large tank is required as a liquid storage tank because the waste liquid is collectively processed, and the processing cost is high. In addition, the activated sludge method requires a long time for decomposing organic matters, and moreover, it is necessary to dilute the waste liquid to a concentration suitable for the production of algae and bacteria, and therefore it is necessary to take a large amount of activated sludge equipment.

Further, Japanese Patent Application Laid-Open No. 64-27698 discloses an apparatus for reacting a monomer in an impregnation treatment waste liquid in a polymerization tank and then separating the solid content and the treatment liquid. As the (meth) acrylic acid ester used, those containing a large amount of water-soluble components in order to improve the cleaning effect are the mainstream, and when this type of impregnating liquid is subjected to the above-mentioned polymerization treatment, a viscous gum-like gel Is generated. This gel adheres to the inside of the device, blocks the discharge port, and is difficult to separate and remove, which causes a problem in operation or maintenance. In addition, it takes a long time to perform the processing sufficiently.

In JP-A-1-164491, in order to improve the treatment effect, a curing agent composed of an azoamidine compound or an azoamide compound is added to a waste liquid containing a (meth) acrylic acid ester, and a solid content and a treatment after the polymerization treatment are added. A method of separating the liquid is disclosed. However, this method has a problem that it takes several hours to 20 hours to carry out the treatment, and a sticky gum-like gel is produced when the treatment is carried out in a short time.

[0006] In Japanese Patent Laid-Open No. 1-155987, a silicate is added to and mixed with a waste liquid containing acrylic acid, and then pH is set to 5 or less by addition of an acid to agglomerate the derivative to improve gel morphology and centrifuge. A method of separating a solid content and a treatment liquid by separation is disclosed. However, according to this method, there is a problem that the water-soluble component remains dissolved in water and is unlikely to be aggregated, and the COD of the treatment liquid does not decrease so much.

Japanese Unexamined Patent Publication (Kokai) No. 3-224692 discloses a method of decomposing (meth) acrylic acid ester in waste liquid by using a wet oxidation reaction vessel filled with a solid catalyst. However, according to this method, there is a problem that a reaction tank and a peripheral device having a dedicated heat exchange function are required, and an installation area or cost is increased.

[0008]

DISCLOSURE OF THE INVENTION In view of the problems of the above-mentioned conventional techniques, the present invention chemically treats a monomer into a water-insoluble granular polymer in the treatment of a waste liquid containing a (meth) acrylic acid ester, It is intended to facilitate separation of the polymer after the treatment, simplify the handling, reduce the COD concentration in the treatment solution, and perform the treatment in about 1 to 2 hours including the temperature rising time. .

[0009]

That is, the present invention is (meta)
At the time of heat-polymerizing a waste liquid containing an acrylic ester, at least one or more substances having adsorptivity are added, or at least one or more substances having cohesive properties are added, and the effect of the flocculant is obtained. Depending on pH
Is adjusted, or at least one or more azo compound-based or peroxide-based free radical catalysts or other free radical catalysts are added as a curing agent, and the treatment is carried out to solve the problems of the prior art. I was able to do it.

Included in the waste liquid targeted by the present invention,
The (meth) acrylic acid ester includes all known polymerizable monomers used for sealants for impregnating agents. That is, the monofunctional ester has the following formula.

[0011]

Embedded image CH ₂ ═C (R ¹ ) COOR ²

Here, R ¹ is H or CH ₃ , and R ² is C _n H.
_{2n + 1} or ^{_{C n H 2n OR 3, (}} - CH 2 CHR 4 O) m C n H
_{2n + 1} or _{^{(-CH 2 CHR 4 O) m}} '(CH 2 CHR 5 O)
_l C _n H _{2 n + 1} , where n is 1 to 18, R ³ , R ⁴ and R ⁵ are H,
Alternatively, it is an alkyl or aryl group having 1 to 18 carbon atoms, which is substituted or unsubstituted with a halogen atom, cyano, amino, alkylamino, ether, cycloalkyl group or the like. Further, m is 1 to 10 and m ', l is 0 to 10. For example, acrylic acid or methacrylic acid methyl, ethyl, butyl,
Lauryl, stearyl, 2-ethylhexyl, hydroxyethyl, hydroxypropyl, hydroxybutyl, hydroxyhexyl, 3-chloro-2-hydroxypropyl, 3-bromo-2-hydroxypropyl, polyhydroxyethyl, polyhydroxypropyl, phenyl, naphthyl, Examples include hydroxyphenyl, cyclohexyl, tetrahydrofurfuryl, cyanoethyl, butylaminoethyl, chloroethyl, trifluoroethyl, tetrafluoropropyl, glycidyl ester and the like.

As the polyfunctional monomer having two or more acrylic or methacrylic groups CH ₂ ═CR ¹ COO-, ethylene glycol, polyethylene glycol, propylene glycol, polypropylene glycol, glycerin, polyglycerin, trimethylol is used. Examples include polyhydric alcohols such as propane and pentaerythritol, and di- or tri- and polyacrylates or polymethacrylates of polyhydric phenols such as bisphenol A and resorcin.

The adsorptive substance used in the first invention includes all known adsorptive substances. That is, the substance has fine holes and gaps, and particles can be physically adsorbed in the fine holes and gaps. Examples thereof include, but are not limited to, activated carbon, silica gel, zeolite, bentonite, silicate minerals such as acid clay, and commercially available adsorbent powder.

The addition ratio of the powder having adsorptivity is effectively in the range of 0.1 to 10% by weight, preferably 0.3 to 5% by weight, based on the treatment waste liquid. Adsorbent powder concentration is 0.1% by weight
Below, it becomes a sticky gum-like gel,
If the amount is more than 10% by weight, the amount of flocs increases and the sludge treatment cost increases.

The cohesive substance used in the second invention includes all known cohesive substances. That is, the surface potential of powder or particles such as a liquid or colloid solution in which powders or fine particles are stably dispersed in a solvent is neutralized to disperse dispersed particles. Examples thereof include, but are not limited to, a polyaluminum chloride solution, a sulfuric acid band, iron chloride, a polymer coagulant, and a commercially available coagulant.

The addition ratio of the above-mentioned substance having cohesiveness is effective in the range of 50 to 10,000 ppm, preferably 100 to 1000 ppm with respect to the treatment waste liquid. Flocculant concentration is 50pp
Below m, it becomes a sticky gum-like gel,
If it is 0000 ppm or more, the amount of the additive is large and the cost is high.

The hardeners used in the present invention can be used alone or in combination of two or more as long as they are known to this type of impregnating agent. Examples of peroxides include ketone peroxides such as methyl ethyl ketone peroxide and cyclohexanone peroxide; peroxyketals such as 1-1-bis (t-butylperoxy) cyclohexane and 2,2-bis (t-butylperoxy) butane; cumene hydro. Hydroperoxides such as peroxides and t-butyl hydroperoxides; Dialkyl peroxides such as di-t-butyl peroxide and di-cumyl peroxide; Diacyl peroxides such as acetyl peroxide and benzoyl peroxide; Di-propyl peroxydicarbonate and di- Peroxydicarbonates such as 2-ethylhexyl peroxydicarbonate;
Peroxyesters such as t-butylperoxyacetate and t-butylperoxybenzoate; acetylcyclohexylsulfonyl peroxide and the like.

As the azo compound, 2,2'-azobisisobutyronitrile and 2,2'-azobis-2,4 are used.
-Dimethylovaleronitrile, 1,1'-azobiscyclohexane-1-carbonitrile, 2,2,4-trimethyl-2
-Phenylazovaleronitrile, 2,2'-azobis-4-
Methoxy-2,4-dimethylvaleronitrile, 1,1'-
Azobis-1-cyclobutanenitrile, 2,2′-azobis-2-methylbutyronitrile, 2,2′-azobis-2-
Azonitriles such as ethylpropionitrile, 1,1′-azobis-1-cyclopentanenitrile and 2,2′-azobis-2-cyclopropylpropionitrile; 4,
Azocarboxylic acids and azo esters such as 4'-azobis (4 methylpentanoic acid) and 2,2'-azobisisobutyrate; (1-phenylethyl) azodiphenylmethane, 2,2'-azobis (2-methylpropane) And azoalkanes and azoarenes; 2,2'-azobis {2-methyl-N- [1,1-bis (hydroxymethyl) -2-hydroxymethyl] propionamide}, 2,2'-azobis {2-methyl -N- [1,1-bis (hydroxymethyl)
Ethyl] propionamide}, 2,2'-azobis [2-
Methyl-N- (2-hydroxyethyl) -propionamide], 2,2′-azobis (2-methylpropionamide) dihydrochloride and other azoamides; 2,2′-azobis (2-methylphenylpropionamidine) Dihydrochloride,
2,2'-azobis [N- (4-chlorophenyl) -2-methylpropionamidine] dihydrochloride, 2,2'-azobis [N- (4-hydroxyphenyl) -2-methylpropionamidine] dihydrochloride , 2,2'-azobis [N- (4-
Aminophenyl) -2-propionamidine] tetrahydrochloride,
2,2'-azobis [2-methyl-N- (phenylmethyl)
Propionamidine] dihydrochloride, 2,2′-azobis [2-methyl-N-2-propenylpropionamidine] 2
Hydrochloride, 2,2'-azobis (2-amidinopropane) 2
Hydrochloride, 2,2′-azobis [N- (2-hydroxymethyl) -2-methylpropionamidine] dihydrochloride, 2,
2'-azobis [2- (5-methyl-2-imidazoline-2-
Il) propane] dihydrochloride, 2,2′-azobis [2-
(2-Imidazolin-2-yl) propane] dihydrochloride,
2,2'-azobis [2- (4,5,6,7-tetrahydro-1H-1,3-diazepin-2-yl) propane] dihydrochloride, 2,2'-azobis [2- (3,3 4,5,6-tetrahydropyrimidin-2-yl) propane] dihydrochloride,
2,2'-azobis [2- (5-hydroxy-3,4,5,
6-Tetrahydropyrimidin-2-yl) propane] dihydrochloride, 2,2'-azobis {2- [1- (2-hydroxymethyl) -2-imidazolin-2-yl] propane} dihydrochloride, 2, Azoamidines such as 2'-azobis [2- (2-imidazolin-2-yl) propane] and the like, and particularly preferably the above-mentioned curing agent which is water-soluble in the state of use.

The proportion of the curing agent added is suitably in the range of 0.01 to 10% by weight, preferably 0.1 to 5% by weight, based on the (meth) acrylic acid ester in the treatment waste liquid.

The treatment temperature of the present invention is the treatment liquid temperature of 60 ° C.
It is preferable to heat so as to become the above and to perform the treatment for 20 minutes or more. And, more preferably, 90 ℃
With the above, it will be processed in 40 minutes or more.

When a flocculant is used, the pH is adjusted to around 9 with an alkaline reagent such as sodium hydroxide.

[0023]

EXAMPLES Examples of the present invention are shown below. In the impregnation treatment of aluminum die castings and cast products, the first cleaning tank waste liquid immediately after replacement was used as a test liquid from a processing line using an organic impregnation liquid (trade name: Nissei Seal P04, NISSEI). When the COD of the test liquid was measured, it was 30,000 ppm.

Example 1 2 kg of the test solution was sampled at a temperature of 95 ° C. by combining 0.5% by weight of the adsorbent powder shown in Table 1 and 250 ppm of a curing agent.
The reaction was carried out for 1 hour in a hot water bath. After the treatment, each solution was colorless and transparent and had a COD of about 3,000 to 10,000 ppm, and the resulting sludge formed granules of 1 to 5 mm.

[0025]

[Table 1]

Example 2 2 kg of the test solution was sampled, and the coagulant 250 shown in Table 2 was collected.
After adding ppm and adjusting the pH to 9 respectively,
The combination of adding 250 ppm of the curing agent was reacted for 1 hour in a 95 ° C water bath. After the treatment, each solution was colorless and transparent and had a COD of about 3,000 to 10,000 ppm, and the sludge thus formed formed granules of 1 to 5 mm.

[0027]

[Table 2]

Example 3 2 kg of the above-mentioned test solution was sampled, and activated carbon as an adsorbent was added to 0.3 kg.
% By weight, and 2,2'-azobis [2-
250 (2-imidazolin-2-yl) propane] dihydrochloride
Add ppm and react in a water bath at 95 ° C for 1 hour. COD of the impregnating agent (NISSEI SEAL P04, NISSEI) is added to the treated solution.
Is added to about 30,000 ppm, and the same treatment is repeated 20 times.
The solution after each treatment is colorless and transparent and has COD of about 2000 ppm,
The resulting sludge formed granules of 1-5 mm.

Example 4 2 kg of the above test solution was sampled, 250 ppm of a polyaluminum chloride solution was added as a coagulant, and the pH was adjusted to 9, and then 2,2'-azobis (2- Add 250 ppm of methylpropionamidine) dihydrochloride and react in a 95 ° C water bath for 1 hour. An impregnating agent (NISSEI SEAL P04, NISSEI) is added to the solution after the treatment until the COD reaches about 30,000 ppm, and the same treatment is repeated 20 times. The solution after each treatment is colorless and transparent, COD is about 2000 ppm, and the sludge produced is 1 to
A 5 mm grain was formed.

Comparative Example 1 2 kg of the above test solution was sampled and reacted in a water bath at 95 ° C. for 1 hour (without addition of an adsorbent, a coagulant or a curing agent). The treated solution became cloudy and solid-liquid separation was not possible, and COD was 20000 ppm or more.

COMPARATIVE EXAMPLE 2 2 kg of the test liquid was sampled and used as a curing agent.
-Azobis (2-methylpropionamidine) dihydrochloride,
Add 250ppm each of 2,2'-azobisisobutyronitrile and 2,2'-azobis [2- (2-imidazolin-2-yl) propane] dihydrochloride and react in a water bath at 95 ° C for 1 hour. (No adsorbent or coagulant was added). All the solutions after the treatment are colorless and transparent and have an average COD of about 3000 ppm, but the resulting sludge is a viscous gum-like gel,
It also adhered to the container and stirrer.

Comparative Example 3 2 kg of the test solution was sampled, 100, 250, 500 and 1000 ppm of polyaluminum chloride solution was added as a coagulant, and the pH was adjusted to 9 respectively, and then a bath at 95 ° C. was used. In 1
Reacted for a time (no addition of curing agent). The sludge after treatment was in the form of flocs of 1 to 5 mm, but the COD of the treatment liquid was about 20000 ppm or more in all cases.

[0033]

According to the treatment method of the present invention, the waste liquid containing the (meth) acrylic acid ester becomes sludge which can be easily separated in a short time and the treatment liquid which can be treated by reuse or conventional wastewater treatment. There is an effect that can be separated.

Claims (6)

(57) [Claims] 1. A substance having an adsorptivity to a waste liquid containing an acrylic acid ester or a methacrylic acid ester, at least 1.
One or more, and at least one or more azo compound-based or peroxide-based other free radical catalysts as a curing agent are added, and the monomer is heated and polymerized into a granular form to form a water-insoluble polymer. A method for treating a waste liquid containing an acrylic acid ester or a methacrylic acid ester, characterized in that the COD concentration in the treatment solution is lowered by chemically changing the concentration to COD. 2. A treatment waste liquid containing an adsorbent substance,
The processing method according to claim 1, wherein 0.1 to 10% by weight is added. 3. At least one substance having cohesiveness in a waste liquid containing an acrylic ester or a methacrylic ester.
One or more of these monomers are added, the pH is adjusted according to the effect of the flocculant, and at least one or more azo compound-based or peroxide-based other free radical catalysts are added as a curing agent. A method for treating a waste liquid containing an acrylic acid ester or a methacrylic acid ester, characterized in that the COD concentration in a treatment solution is lowered by chemically polymerizing the above into a polymer which is insoluble in water by heat polymerization. 4. A treatment waste liquid containing a substance having a flocculant,
The treatment method according to claim 3, wherein 50 to 10,000 ppm is added. 5. The treatment method according to claim 1, wherein the curing agent is added in an amount of 0.01 to 10% by weight with respect to the acrylic acid ester or the methacrylic acid ester in the treatment waste liquid. 6. The treatment method according to claim 1, wherein the treatment solution is heated to a temperature of 60 ° C. or higher and reacted for 20 minutes or longer.