JPH06170378A - Treatment of waste containing phenols and aldehydes - Google Patents

Abstract

PURPOSE:To purify waste water containing phenols and aldehydes in high concn. to reduce the concn. of phenols and aldehydes to specific low concn. CONSTITUTION:0.1-5wt.% of sulfuric acid and 0.1-5wt.% of gum arabic are added to waste water containing phenol and formaldehyde in high concn. and this waste water is heated at 70-100 deg.C under stirring to reduce the concn. of phenol and formaldehyde to below 1,000ppm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating wastewater containing phenol / aldehydes, and more particularly to a pretreatment method for efficiently treating wastewater containing phenol / aldehydes mainly generated in a phenol resin production process. Regarding

[0002]

2. Description of the Related Art As a method for treating wastewater containing phenols and aldehydes (hereinafter referred to as phenol / aldehyde-containing wastewater), there is a conventional method as disclosed in JP-B-60-
The bacterial treatment method (activated sludge method) as described in Japanese Patent No. 15397 is generally used.

However, in the wastewater treatment of wastewater containing phenol / aldehydes by the activated sludge method, there is a great concern that bacteria will be killed, especially when phenols are present at a high concentration. It becomes necessary to take measures such as
The processing cost is high.

[0004]

SUMMARY OF THE INVENTION In view of the above situation, the present invention mainly aims at reducing the amount of waste water containing a high concentration of phenols and aldehydes generated when a phenol resin is produced in an aqueous system. It is an object of the present invention to provide an efficient pretreatment method in which it is possible to easily treat residual substances without increasing the amount.

[0005]

The present invention has been achieved as a result of earnest research for solving such problems. That is, according to the present invention, 0.1 to 5% by weight of sulfuric acid and 0.1 to 5% by weight of gum arabic are added to a wastewater containing phenols and aldehydes at a high concentration of 1,000 ppm or more, to 70 to 70% by weight. The gist is a method for treating wastewater containing phenol / aldehydes, which is characterized by heating and stirring at 100 ° C.

The present invention will be described in detail below. The phenol / aldehyde-containing wastewater to be treated by the method of the present invention is a wastewater containing phenols and aldehydes discharged in the phenol resin manufacturing process at a high concentration of 1,000 ppm or more. Is phenol or a phenol derivative, and examples of this phenol derivative include m-cresol, p-ter-butylphenol, o-propylphenol, resorcinol, bisphenol A, and the like, or a mixture of one or more of these. Is included. Examples of aldehydes include formaldehyde, paraformaldehyde, acetaldehyde, furfural, and the like.
A mixture of one or more of these is included. In addition to these main raw materials, catalysts such as ammonia water, hexamethylenetetramine, dimethylamine, hydrochloric acid and sulfuric acid, auxiliary raw materials and additives such as emulsion stabilizers such as polyvinyl alcohol, and reaction between phenols and aldehydes It also contains low molecular weight phenol-aldehyde condensates (phenolic resin intermediates, by-products) such as resole and novolac, which are soluble in the produced aqueous medium.

The sulfuric acid added in the method of the present invention is diluted sulfuric acid,
Either concentrated sulfuric acid or fuming sulfuric acid may be used, and the addition amount thereof is preferably 0.1 to 5% by weight in terms of fuming sulfuric acid, based on the weight of waste water. If the addition amount of sulfuric acid is less than 0.1% by weight, the polymerization rate is low and the phenol content cannot be reduced to less than 1.000 ppm in a short time. Further, even if it exceeds 5% by weight, the polymerization rate does not further increase, and on the other hand, the alkali consumption required for neutralization increases, which is not preferable in terms of environmental pollution and treatment cost.

On the other hand, the gum arabic added by the method of the present invention is natural gum arabic derived from sap of legume Acacia senegal Willd, semi-synthetic gum arabic obtained by processing these, or synthetic gum arabic derived from synthetic rubber latex. The rubber is preferably added in an amount of 0.1 to 5% by weight based on the phenol content. This added amount is
If it is less than 0.1% by weight, the phenol resin produced by heating and stirring cannot maintain independent particles, and it becomes a viscous mass and adheres to the stirring blades and the like, which makes post-treatment difficult. Further, even if the amount of gum arabic exceeds 5% by weight, there is no difference in stability of the phenol resin particles formed, and on the other hand, the load in the final treatment step such as the activated sludge method becomes high, which is not preferable.

The above-mentioned addition of sulfuric acid and gum arabic is usually carried out at a room temperature while stirring, and is carried out by any one of a method in which the waste water is added all at once, a method in which it is gradually injected or a method in which it is carried out stepwise. . Add this water at 70-100 ° C for 0.5-
Heat and stir for 5 hours, then cool to room temperature.

According to the method of the present invention, most of the phenols and aldehydes dissolved at a high concentration of 1,000 ppm or more polymerize rapidly and precipitate / aggregate from an aqueous medium to form fine particles that are easy to solid-liquid separate. It becomes a phenol resin and precipitates or disperses in an aqueous medium. Thus, the concentration of phenols and aldehydes can be reduced by separating this particulate phenol resin with a separating means such as filtration or centrifugation.
Waste water of 1,000ppm or less. If any of the phenols and aldehydes in the wastewater before treatment is significantly biased with respect to their equivalents, the deficient components are added until they almost reach the equivalents, and then the Preference is given to applying the method.

Wastewater containing less than 1.000 ppm of phenol pretreated in this way is treated by an activated sludge method, an activated carbon adsorption method,
By efficiently applying a conventionally known final water treatment method such as a chemical oxidation method, highly purified harmless treated water can be reduced to a natural water system such as a river or sea.

[0012]

EXAMPLES Next, the present invention will be specifically described with reference to examples. In addition, the content of phenol and formaldehyde in waste water or treated water in each of the following examples was measured by the following method. Phenol: JIS-K0102-86-28-1.2
Based on 4-aminoantipyrine absorptiometry. Formaldehyde: JIS-K0102-86-29-
Measured by acetylacetone absorptiometry based on 1.

Examples 1 to 4 A reaction solution prepared by phenol-formalin formalin by a water-based emulsion polymerization in the presence of a basic catalyst was subjected to centrifugation to solid-liquid separate fine-particle resin components, and the remaining phenol Formaldehyde-containing wastewater (characteristics are shown in Table 1) was placed in a glass-lined reaction can, sulfuric acid and gum arabic in the amounts shown in Table 1 were added, and the mixture was heated and stirred at 95 ° C. for 3 hours. After completion of the reaction, the phenol resin particles were neutralized to pH 6 to 7, and the phenol resin particles coagulated and precipitated were separated by filtration and the phenol and formaldehyde concentrations in the filtrate were quantitatively analyzed to obtain the results shown in Table 1.

Comparative Examples 1 and 2 As in Example 1, except that sulfuric acid and gum arabic were used.
The amount shown in Table 1 was changed and the wastewater containing phenol and formaldehyde was treated to obtain the results shown in Table 1.

[0015]

[Table 1]

As is clear from Table 1, the method of the present invention (Examples 1 and 2) is an extremely efficient pretreatment method for easily reducing the waste water containing phenol and formaldehyde at a high concentration to less than 1.000 ppm. It is clear that

[0017]

INDUSTRIAL APPLICABILITY The present invention provides an excellent wastewater treatment method capable of treating wastewater containing a high concentration of phenol and formaldehyde at low cost and efficiently to obtain treated water from which both components have been significantly removed. Yes, this treated water can be reduced to completely purified water by performing a secondary treatment such as an ordinary activated sludge method.

Claims (1)

[Claims] 1. The amount of phenols and aldehydes is 1,000 p
Phenol characterized by adding 0.1 to 5% by weight of sulfuric acid and 0.1 to 5% by weight of gum arabic and agitating at 70 to 100 ° C. and treating the wastewater containing at a concentration of pm or more with respect to the weight of the wastewater -Treatment method for wastewater containing aldehydes.