JPS6048236B2 - Polyurethane foam for wastewater and oil treatment containing surfactants - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a polyurethane foam suitable for adsorption treatment of oil contained in wastewater containing surfactants, without the need for the conventional subsequent treatment of coarsening the oil. The aim is to create a polyurethane foam that can be completely adsorbed.

Conventional adsorbents such as nonwoven fabrics such as polypropylene, polyethylene, and nylon fibers or polyurethane foams have almost no adsorption effect on wastewater containing surfactants. This method first required a primary treatment such as agglomeration as a step of coarsening the finely divided oil particles, and then adsorption treatment of the coarsened oil particles as a secondary treatment.

Therefore, the inventors have simplified the treatment of cooking oil wastewater by omitting the conventional primary treatment, and it has been proposed that it can be easily and easily treated even in places without special equipment, that it can be used widely, and that it can be used to purify the environment. In order to contribute to this, we began investigating polyurethane foams that give the polyurethane foam itself the ability to coagulate during primary treatment, and discovered the possibility of almost complete oil adsorption treatment without primary treatment using the cationized polyurethane foam described later. .

In addition, with ionized adsorbents for other plastic materials,
No favorable results were obtained. For example, even if a column is filled with an ion exchange resin and edible oil wastewater is passed through the column, clogging is severe and the column is unusable. That is, this invention focuses on the fact that most of the oil content in oil-containing wastewater is electrostatically anionic.
As a treatment means, it has been discovered that the oil adsorption function can be better exhibited by contacting and adsorbing the oil onto the cationized polyurethane foam.

Furthermore, it has been found that the oil adsorbent according to the present invention exhibits an oil adsorption effect not only for anionic oils but also for nonionic oils. This action is thought to be due to the following two steps acting instantaneously to adsorb oil.
That is, first, one ionic group, that is, a cationic group, dotted on the cell surface of polyurethane foam neutralizes the surface charge of oil emulsion particles in wastewater stabilized by a surfactant, and the oil particles In the next step, the oil molecules that have become coarse particles are processed by the physical adsorption filtration ability of the polyurethane foam itself, which forms a fine foam structure (cells) suitable for filtration. Therefore, it adsorbs efficiently, and these functions are performed continuously and instantaneously in the same adsorbent.

In this case, it has also been found that the less commonly used cell stabilizers, such as silicone stabilizers, are used in the process of producing polyurethane foam, the better the adsorption effect.

The oil content of the oil-containing wastewater that is the target of this cationized polyurethane foam includes not only ordinary floating oil but also compressor drain oil, which is a mixture of oil and surfactant, rolling oil, cutting oil, and gas station oil. There are waste oils, etc., and all of these contain surfactants, so
This creates an emulsion.

In the case of a continuous system, this polyurethane foam is used as an adsorbent by filling a column with the polyurethane foam and circulating the wastewater through the column to absorb the emulsion oil in the wastewater. The oil adsorption effect can also be obtained by adding this polyurethane foam to an oil-containing wastewater bit as another method of use.

However, the method is not limited to these methods. As mentioned above, the above-mentioned ionized polyurethane foam exhibits an unexpectedly remarkable adsorption capacity.

Next, three main components for producing the polyurethane foam for treating oil-containing wastewater, particularly surfactant-containing wastewater, of the present invention will be explained.

For component a (polyol): A polyfunctional polyoxyalkylene polyol or a bifunctional lipophilic polyol may be used alone or in a mixture of both.

This polyol component is generally used for producing polyurethane, and polyoxyalkylene polyol is, for example, a polyol of a polymerization product or copolymer of tetrahydrofuran, ethylene oxide, propylene oxide, butylene oxide, etc. ~100
It has a molecular weight of 0 degrees, preferably 200 to
It has a molecular weight of 8000.

A bifunctional lipophilic polyol has a molecular weight of 1000 to 3.
Polybutadiene glycol with an aquatic group at the end, which is a copolymer of butadiene and acrylonitrile or styrene, or a carbonized polyolefin with a molecular weight of 1,000 to 300 aquatic groups at the end. It is a hydrogen compound (polyethylene glycol, etc.).

Regarding component b (cationic group-containing chain extender): this b
This component is different from conventional polyurethane foams, and the presence of this component (b) makes the polyurethane foam of the present invention electrostatically cationic. That is, this cationic group-containing chain extender is a compound that contains a group that can be converted into a cationic group and has 2 to 3 active hydrogens that can react with an organic isocyanate, and accounts for 5 to 15% by weight of the compound. In the presence of water,
A liquid ionic group-containing chain extender ionized with an alkylating agent is used.

Furthermore, when foaming polyurethane, an ordinary chain extender having no ionic group may be used in combination, if necessary. For example, a compound that has tertiary nitrogen or secondary sulfur that can be converted into a cationic group, and has 2 to 3 active hydrogens (mainly -0H) that can react with organic isocyanates, that is,
For the former, N-methyldiethanolamine, N-butyldiethanolamine, triethanolamine and the like are preferred, and for the latter, dihydroxyethyl sulfide and the like are preferred.

These compounds depend on the following alkylating agents. It is cationized. Examples of this alkylating agent include dialkyl sulfuric acid such as dimethyl sulfate and diethyl sulfate, alkyl halides such as methyl chloride and ethyl bromide, or benzyl chloride. In the case of dialkyl sulfuric acid, water must be added after quaternization. There is.

That is, component b can react with isocyanate groups.

tertiary nitrogen compounds mainly having 2 to 3 0H end groups,
Or a secondary sulfur compound, 5 to 1 of these compounds
It is a chain extender which is alkylated in the presence of 5% (by weight) of water to have a cationic group and an active hydrogen group in its molecule. The action of water in this case is to maintain uniform reactivity by reducing the viscosity in the reaction system and to participate as a so-called water blowing agent in the reaction with isocyanate groups in the subsequent step. Examples of chain extenders that do not have an ionic group and are used in combination as necessary include polyols such as ethylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and glycerin, or ordinary amino alcohols. or amine*(%=
"93LA(7)N (TS" x 100) Due to the weight of all polyurethane raw materials, that is, the b component starting material.

The weight percentage of N1 or S1 is preferably 0.3 to 1.5%. The ionic group content concentration can be adjusted by increasing or decreasing the amount of component b used. If it is less than 0.3%, the surface charge of the oil-containing wastewater emulsion particles, that is, the Θ-charged oil emulsion particles, is neutralized by the one ion possessed by the cationized polyurethane foam due to the low one charge. Due to the low aggregation and coarsening effect of oil emulsion particles caused by this, the oil adsorption capacity of so-called cationized polyurethane foam is insufficient, and when it exceeds 1.5%, the concentration of ionic groups increases. However, on the other hand, if component b, i.e., chain extender, is added too much, the resulting cationized polyurethane foam becomes excessively crosslinked (1), resulting in physical properties that are too hard and brittle. However, due to its low elasticity, it is not suitable for use as an oil adsorption treatment material as it will be crushed during the filling operation into a column.

There is something similar. For component c (polyisocyanate): A single aliphatic or aromatic polyisocyanate or a mixture of both may be used.

That is, the polyisocyanate may be an aliphatic or aromatic polyisocyanate used in conventional polyurethane foams.

For example, 2.4-tolylene diisocyanate, 2.6
- tolylene diisocyanate or a mixture thereof; 4.
Examples include 4-diphenylmethane diisocyanate, 1,5-naphthylene diisocyanate, and other polyphenyl polyisocyanates (eg, triphenylmethane-P-triisocyanate). Preferably, a mixture of 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and polyphenyl polyisocyanate is used. By reacting the above three components, foaming and curing of the resin occurs in the same manner as the foaming reaction of ordinary polyurethane foam.

Among the obtained cationized polyurethane foams, those suitable for treating wastewater oil containing the surfactant of the present invention have a high concentration of ionic groups in the entire foam, and then react with the above three components as main components. An example of the cationized polyurethane foam adsorbent obtained by this method will be explained. Table 1 Composition of cationized polyurethane foaming stock solution (Note) (a) FA7O Ξ 4-functional polyol manufactured by Yokasei Kogyo Co., Ltd., 0H value 38. (b
) Ionic group-containing chain extender N-methyldiethanol 44 parts of amine, 46 parts of benzyl chloride, and m parts of water were mixed and stirred at 80°C and reacted for 2 hours.

(c) MDI-CR Manufactured by Mitsui Nisso Polyurethane Co., Ltd., crude 1VDI, a mixture of diphenylmethane diisocyanate and higher polyisocyanate.

(c) 'IT) 180 80/20 mixture of 2.4-tolylene diisocyanate/2.6-tolylene diisocyanate.

The cationized polyurethane foam adsorbent obtained using the above three components (a), (b), and (c) as main components is:
Using a high-speed stirrer, add the ionic group-containing chain extender (b) to (a).
An emulsion is obtained by mixing and stirring with FA7O2. next,
Quickly mix and stir the catalyst (d), and finally add the isocyanate (C) and mix and stir.The specific gravity is 0.03.
An open-cell cationic group-containing polyurethane foam having a cationic group-containing concentration of 0.9% (by weight) is obtained. In addition,
No cell stabilizer is used in the cationized polyurethane foam used in this invention. Next, the results of a comparison based on examples will be shown regarding the oil adsorption ability of oil-containing wastewater when the cationized polyurethane foam adsorbent is used to treat the oil-containing wastewater.

Example 1 1000 ppm of an anionic surfactant (D.B.S type) as a surfactant was added to an oil/water mixed compressor drain containing 1000 ppm of oil and stirred to obtain an oil particle size of 1 to 10.
Prepare oil-containing water emulsified with P, and test water 1.
Put e into a beaker, add 15 g of adsorbent made by shredding the cationized polyurethane foam listed in Table 1 into 3 to 5 pieces in diameter, and soak it in the beaker. After leaving it for a day and night, squeeze the cationized polyurethane foam lightly. The oil content of the treated water that remained in the beaker was measured by carbon tetrachloride extraction infrared analysis method (JIS KOLO infrared analysis method), and the results are shown in Table 2 below.

For comparison, 5g of conventional polyurethane foam (specific gravity 0.03, shredded into size diameter 3-5TmIn)
In addition, a commonly used polypropylene adsorbent (polypropylene fiber non-woven fabric with a bulk specific gravity of 0.3
) 15g, and surface-treated polyethylene emulsion oil adsorbent (1.5~2rn/M4) x 3~4m
The results of a comparative test in which 15 g of cationic polyurethane foam was treated in the same manner as the cationized polyurethane foam are shown in the second table.
Shown in the table.

Example 2 1000 ppm of a nonionic surfactant (Neugen Ell2O manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) as a surfactant was added to oil/water mixed compressor drain oil containing 1000 ppm of oil and stirred to form an emulsion with an oil particle size of 1 to 10p. The sample water was treated in the same manner as in Example 1, and the oil content after adsorption was measured. The results are shown in Table 3 below.

Claims (1)

[Scope of Claims] 1. A cationic group containing concentration of 0.3 to 1.0% obtained by subjecting the following three main components a, b, and c to a urethane foaming reaction.
A polyurethane foam for wastewater oil treatment containing 5% by weight of an anionic or nonionic surfactant. Component a: A polyfunctional polyoxyalkylene polyol or a bifunctional lipophilic polyol, each singly or a mixture of both. Component b: A tertiary nitrogen compound or a secondary sulfur compound having 2 to 3 active hydrogen atoms capable of reacting with an organic isocyanate is added to an alkylating agent in the presence of water in an amount of 5 to 15% by weight of the compound. A cationic group-containing chain extender that is thus cationized. Component c: aliphatic or aromatic polyisocyanate alone or a mixture of both.