SU1467036A2 - Method of purifying waste water from dyes - Google Patents

Abstract

The invention relates to the treatment of wastewater from organic dyes by isolating them in the form of colored oligomers with dye recovery. The aim of the invention is to increase the degree of purification. For carrying out the process, before or simultaneously with the treatment with urea urea and formaldehyde in a specific ratio, kaolin is introduced into the wastewater in an amount of 1.5 - 12 g / l. In the process of copolymerization a precipitate is formed which is separated by filter; by the The resulting colored oligomer contains 25–30% of the dye. The method allows to purify wastewater up to 99.8% and, without additional discoloration, be sent for bioremediation. 1 tab.

Description

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The invention relates to methods for purifying waste water from dyes by means of them in the form of colored oligomers, allows utilizing recoverable components and is an improvement of the method according to the authors. St. 1116016 ..

The aim of the invention is to increase the degree of purification.

For carrying out the process, kaolin in an amount of 1.5-12 g / l is introduced into the wastewater before or simultaneously with the introduction of monomers (urea and formaldehyde). Used dyes can be recycled.

When cleaning concentrated wastewater (especially when removing acid dyes) containing 3-Gp g / l dyes (which is typical

for the production of active dyes, which are a type of acid dyes), the use of natural sorbents is inefficient.

In the proposed method, kaolin is used not as an adsorbent, but as a source of Al ions, which form associates with the products of the interaction of the urea-formaldehyde oligomer and dyes. The formation of such associates enhances the degree of wastewater treatment from dyes.

The addition of an additive leads to an increase in the degree of purification only when it is carried out before the formation of a urea formaldehyde oligomer, i.e. prior to the introduction (or simultaneous introduction) of monomers (

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Chevina and formaldehyde). If kaolin is introduced after monomers, it has almost no effect on the degree of purification, which confirms the role of kaolin as a chemical modifier.

Consumption of kaolin 1.5-12 g / l is based on experimental data. Reduced consumption (below 1.5 g / l) leads to a decrease in the degree of purification. Increasing the flow rate (over 12 g / l) does not lead to a further increase in the cleaning efficiency and, therefore, is unreasonable.

Examples 1-8. The waste water produced by the dye of bright red 6c (the content of the dye is 20 g / l, the content of NaCl is 140 g / l, pH 6.5) at 25 ° C and under stirring, urea is loaded in an amount of 30 g / l (1.5 wt.h. per 1 part dye), formaldehyde in the amount of 1.35 M per 1 M ureas, hydrochloric acid to a pH of 0.75. The parameters for the introduction of kaolin are shown in the table. After stirring for 1 h, about 6 °. The precipitate of the oligomer is separated by filtration. The product can be recycled, for example, for dyeing paper, as the oligomer contains 15-30% dye.

Example 9. In the wastewater of the black active K dye (pH 5, the dye content is 15 g / l, the content of sodium and potassium chlorides is 190 g / l)

with and stirring, load 6 g of kaolin, then after 10 min urea is introduced in the amount of 22.5 g / l

(1.5 ppm, per 1 pitch of dye), formaldehyde in the amount of 1.5 M per 1 M urea and hydrochloric acid to pH 0.8. After 1 h, the colored oligomer was separated by filtration. The residual concentration of the dye in the filtrate is 60 mg / l, the degree of purification is 99.6%. The content of the dye in the oligomer (in terms of dry weight) of 26.3%. Residual dye concentration in

the filtrate by a known method (i.e., without the introduction of kaolin) 210 mg / l, the degree of purification 98.6%.

f Thus, carrying out the purification process according to the proposed method allows increasing the degree of purification from dyes, which allows directing waste water without additional discoloration directly to biological treatment plants.

Claims (1)

Invention Formula thirty Method of sewage treatment from dyes according to auth.St. No. 1116016, characterized in that, in order to improve the degree of purification, kaolin in an amount of 1.5-12 g / l is introduced into 35 wastewaters prior to or simultaneously with the treatment with urea and formaldehyde.