JPS60248286A - Treatment of water containing polyethylene glycol - Google Patents

Abstract

PURPOSE:To insolubilize polyethylene glycol and to treat water by adding a colloidal soln. of polyvalent anions and melamine aldehydic acid to the water contg. polyethylene glycol. CONSTITUTION:When a colloidal soln. of polyvalent anions such as sodium sulfate and melamine aldehydic acid is added to the water contg. polyethylene glycol from surfactant industries, etc., the acidic colloidal soln. is rapidly clouded and flocculated, and the polyethylene glycol is simultaneously insolubilized. Subsequently, the deposit is separated from the water.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] The present invention relates to a method for treating polyethylene glycol-containing water t7).

Polyethylene glycol-containing water is generated as wastewater from surfactant, cosmetic, and pharmaceutical manufacturing industries, as well as industries that utilize surfactants.

Since polyethylene glycol does not have ionic properties, it is said that aggregation treatment is difficult.

As a result of intensive research against this background, the present inventor discovered that coagulation treatment could be carried out extremely efficiently by using a melamine aldehydic acid colloid solution, and filed an application earlier (Japanese Patent Application No. (May 15, 1981).

However, this method has a problem in that when the treatment pH becomes less than 7, the melamine-aldehyde acid colloid begins to shift from the colloidal state to the dissolved state again, resulting in deterioration of the reaction efficiency.

In this invention, in order to solve the problems of the previous application, as a result of further intensive research, it was found that this drawback could be overcome by processing with polyvalent anions,
It is complete.

[Structure of the Invention] The present invention is a method for treating polyethylene glycol-containing water, which is characterized by adding a polyvalent anion and a melamine/aldehyde acid colloidal solution to polyethylene glycol-containing water to perform a flocculation treatment.

Examples of polyethylene glycol-containing water that is the subject of this invention include waste water discharged from surfactant, cosmetic, and pharmaceutical manufacturing industries and surfactant utilization industries, but is not limited to these. Any material containing polyethylene glycol is covered by this invention.

A polyvalent anion and a specific acid colloid solution are added to polyethylene glycol-containing water. In this case, if polyvalent anions already exist in the water to be treated, there is no need to add them externally, but if they do not exist or are insufficient, they should be added externally. At that time, the order of addition of the acid colloid bath liquid and the polyvalent anion is not particularly limited, and either of them may be added to the cow or they may be added simultaneously. However, in the case of simultaneous use (3), the effect may be slightly worse.

Examples of such polyvalent anions include sodium sulfur, potassium sulfate, sodium ligninsulfonate, and sodium vinylsulfonate. Further, as the polyvalent anion used in the present invention, polyhydric alcohols are also suitable, and examples thereof include citric acid, oxalic acid, itaconic acid, and polyacrylic acid. When such polyvalent anions coexist, the p of the water to be treated increases when an acid colloid solution is added.
Even if H is less than 7, there will be no problem and a very wide range of p
Polyethylene glycol is removed well under H range conditions.

On the other hand, the melamine/aldehyde acid colloidal solution used in the present invention is produced by further adding an acid to methylolmelamine obtained by reacting melamine and aldehyde, as shown in the production examples described below. Note that, if necessary, the methylolmelamine may be further converted into an alkyl ether (.1) and an acid may be added thereto.

As the aldehyde, formaldehyde, paraformaldehyde, acetaldehyde, propionaldehyde, etc. can be added, but formaldehyde and paraformaldehyde are preferred from the viewpoint of ease of handling and reaction efficiency.

The ratio of melamine and aldehyde is 1 mole of aldehyde to 1 mole of melamine.However, if the amount of aldehyde exceeds 25 moles, the amount of free aldehyde will increase when an acid colloid solution is prepared. Since free aldehyde becomes a COD source, the amount of aldehyde is preferably 2.5 mol or less where COD is a problem.

The methylolmelamine thus obtained does not dissolve in water, but dissolves in an acid solution in a colloidal state. On the other hand, alkyl etherified methylol melamine obtained by further alkyl etherification of methylol melamine is water-soluble and becomes colloidal when an acid is added.

As the acid used here, a basic acid is suitable.
Basic acids include mineral acids such as hydrochloric acid and nitric acid, as well as formic acid,
Examples include organic acids such as acetic acid, lactic acid, and propionic acid.

Among these, hydrochloric acid is preferable because a stable colloidal solution can be obtained.

The amount of basic acid, especially hydrochloric acid, to be added is 0.5 to 1.5 mol per mol of melamine, preferably 0.7 mol.
~1.3 mol is meth.

If the amount of acid added is less than 0.5 mol, acid colloidal properties cannot be sufficiently developed. On the other hand, if the amount exceeds 15 mol, the stability of the colloidal solution tends to deteriorate.

In this acid colloidal solution of methylolmelamine, there is a large amount of free aldehyde at the initial stage of preparation of the colloidal solution, but if it is left to age at room temperature after preparation, the amount of free aldehyde decreases.

Ripening can also be accelerated by heating. 5 days to 3 months for room temperature aging, 2 months at 50C for heat aging
It was a turtle for about 3 hours.

The amount of acid colloid solution added varies depending on the type of wastewater and the treatment target value, so it is set so that the amount of polyvalent anion is 0.2 to 51 molecules per 971 moles of (7) in the jar test.

In this invention, after adding the acid colloid solution and the polyvalent anion to the target water, there is no need to particularly adjust the pH, and polyethylene glycol is added under the entire pH range, preferably under weakly acidic to alkaline conditions. Agglomeration treatment can be performed well.

The p I-1 may be adjusted if necessary, and known acids and alkaline agents used for pH adjustment may be selected, such as hydrochloric acid, nitric acid, sodium hydroxide, and ammonia.

In addition, in the present invention, only the acid colloid solution and the polyvalent anion may be added to the wastewater, but they may also be used in combination with an inorganic coagulant such as aluminum sulfate or ferric chloride.
It may also be used in combination with an organic coagulant.

As the organic flocculant, polyalkylene polyamines represented by polyethyleneimine (8), water-soluble dicyandiamide-formaldehyde condensates, polydimethyldiallylammonium salts, epihalohydrin-amine condensates, cationized guar gum, and the like can be used.

When an inorganic coagulant and an organic coagulant are used in combination with water in which COD components coexist, it is preferable to add an acid colloid solution simultaneously with or after the addition of these agents. It is not preferable to add the acid colloid solution first because it may act on the COD component, which can be removed by an inorganic coagulant or an organic coagulant.

When a polyvalent anion and an acid colloid solution are added to polyethylene glycol-containing water, the acid colloid solution rapidly becomes cloudy and aggregates, and the polyethylene glycol also becomes insolubilized.

After this reaction has been carried out sufficiently, the precipitate is separated from the water. When separating by coagulation filtration, the suspension may be directly fed to a filtration device filled with a suitable F material.

On the other hand, in the case of coagulation-sedimentation treatment, it is preferable to add an organic polymer flocculant to the suspension, as this will coarsen the flocs and increase the sedimentation rate.

Known organic polymer flocculants can be used, but
Among them, acrylamide-based ones are desirable, such as polyacrylamide, polymethacrylamide, partial hydrolyzate of polyacrylamide or polymethacrylamide,
Examples of the acrylamide ti include copolymers of methacrylamide and other vinyl monomers such as acrylic esters, acrylonitrile, dialkylaminoethyl methacrylate, or quaternized products thereof.

As the precipitation device, a known type such as a circular type or a square type can be used.

In this invention, the removal mechanism of polyethylene glycol by the acid colloid solution is unknown, but when the acid colloid solution is added to the target water, the polyethylene glycol and the acid colloid may react in some way and precipitate in that state. Alternatively, it is presumed that the colloidal nature of the acid colloid solution is broken by the polyvalent anion and the acid colloid solution is combined, and at that time, polyethylene glycol is incorporated and the acid colloid solution becomes unbathable. Considering that other cationic aggregates, Mll-r, are not treated, but are treated with the acid colloid solution, there is a strong possibility that not only the ionicity but also the molecule itself is involved in the reaction. 6. Furthermore, the mechanism of action of polyvalent anions is also not clear.

〔Effect of the invention〕

As described above, while the conventional method had some problems in processing, the method of the present invention allows polyethylene glycol to be processed quickly and efficiently with simple operations.

Hereinafter, the effects of the present invention will be clarified by examples using acid colloid liquids obtained by the following production examples.

[Example of producing acid colloid liquid] Add 63% melamine (0.5 mol) and 30% Tobara formaldehyde (1.0 mol formaldehyde) to 93 ml of distilled water, and adjust the pH to 10.0 with NaOH to 70 ml.
C. to dissolve the melamine. After further reacting at 70C for 5 minutes, the mixture was left at room temperature and gradually cooled to precipitate methylolated melamine crystals. This precipitate was collected on a Buchner funnel, washed with methanol, and then dried under reduced pressure. Elemental analysis of this dried methylolated melamine revealed that melamine:formaldehyde-1:2.1
It was 9.

Add 1 of (0.05 mol) of this methylolated melamine to 100 ml of 1.35% hydrochloric acid solution.
．． 75 mol) and stirred to obtain an acid colloid solution. When used in the following example, the product was further left to mature at room temperature for 12 days.

[Example 1] PEG6000 (manufactured by Kishida Chemical) 21 was added to tap water to make a solution of polyethylene glycol 62plNI,
This water was used as the target water.

500 ml of this target water was sampled into a beer, and if necessary, a sodium hydroxide solution was added to adjust the pH to a predetermined value. The mixture was stirred for 1 minute, then allowed to stand for 15 hours, and then the amount of polyethylene glycol in the supernatant water was measured as TOC.

The results are shown in Figure 1.

[Example 2] The target water prepared in Example 1 was diluted with water (polyethylene glycol 3111F), and sodium salany lignin sulfonate was added to the solution to a volume of 50 pl. To this solution, predetermined amounts of melamine/formaldehyde metal condensate, polyethyleneimine, dimethylamine/epichlorohydrin metal condensate, and aluminum sulfate were added separately, and after stirring for 2 minutes, diluted with hydrochloric acid or hydroxide solution. Neutralized. Thereafter, the mixture was allowed to stand for 15 hours, and the supernatant water was collected and the amount of polyethylene glycol was measured as TOC.

The results are shown in Figure 2.

As can be seen from Figure 1, when the melamine formaldehyde condensate is used alone, polyethylene glycol is not removed when the pH becomes less than 7, and on the contrary, TOC increases in proportion to the amount of the acid colloid solution added. I know what I'm going to do. On the other hand, it can be seen that in the case of the present invention, polyethylene glycol is effectively removed even at a pH of less than 7 simply by the presence of sulfate ions.

On the other hand, Figure 2 shows that with conventional cationic flocculants, even if polyvalent anions coexist, the treatment effect is not reflected at all, and polyethylene glycol is still not removed, whereas in the case of this invention, it is extremely effective. It can be seen that it has been removed.

[Example 3] The same treatment as in Example 1 was performed except that enoic acid was added.

As a result, almost the same results as those shown in FIG. 1 were obtained.

[Brief explanation of drawings]

The drawings show the results of Examples, and both FIGS. 1 and 2 are diagrams showing the relationship between the amount of the drug added and the removal rate of polyethylene glycol. Applicant Kurita Industries Co., Ltd. (15)

Claims (1)

[Scope of Claims] 1. A method for treating polyethylene glycol-containing water, which comprises adding a polyvalent anion and a melamine/aldehyde acid colloidal solution to polyethylene glycol-containing water for flocculation treatment. 2. The method for treating polyethylene glycol-containing water according to claim 1, wherein the melamine/aldehydic acid colloidal solution is composed of methylolmelamine, in which 1 to 6 moles of aldehyde are bonded to 1 mole of melamine, and an acid. 3. The method for treating polyethylene glycol-containing water according to claim 2, wherein the melamine/aldehyde acid colloidal solution is composed of an alkyl etherified methylol melamine obtained by further alkyl etherifying methylol melamine and an acid. 4. The method for treating polyethylene glycol-containing water according to any one of claims 1 to 3, wherein the acid is hydrochloric acid. 5. The method for treating polyethylene glycol-containing water according to claim 4, wherein hydrochloric acid is added in an amount of 05 to 15 moles per mole of melamine. 6. The method for treating polyethylene glycol-containing water according to any one of claims 1 to 5, wherein the polyvalent anion contains a sulfur atom. 7. The method for treating polyethylene glycol-containing water according to any one of claims 1 to 5, wherein the polyvalent anion is a polyvalent carboxylic acid.