RU2029736C1 - Method of sewage treatment from dyes and surface-active substances - Google Patents

Abstract

FIELD: sewage treatment. SUBSTANCE: organic coagulating agent is added to sewage - condensation product of dicyandiamine with formaldehyde and sodium silicate. Optimal time interval between addition of organic coagulating agent and sodium silicate is 3-10 min; optimal ratio of doses is 1:(5-12), respectively. Treatment time is 10-40 min, treatment degree is 98%. EFFECT: increased effectiveness of sewage treatment. 3 cl, 2 tbl

Description

 The invention relates to the treatment of wastewater from dyes and surface-active substances (surfactants) and can be used for wastewater treatment of light industry enterprises and household chemicals.

 Known methods for wastewater treatment from dyes and surfactants using inorganic coagulants, such as soluble salts of aluminum and iron, sodium perchlorant and others, and organic flocculants [1].

 The disadvantages of the known methods are the low cleaning effect of a nonionic type surfactant, the high consumption of reagents when treating water containing a class of active dyes, as well as the complexity of the process due to the need for precise regulation of the pH value.

H₂-

-H где n = 277-347 R - OCH₂CH₂OH n = 1390-8333 R - SO₃H [2]
К недостаткам известного способа можно отнести, то, что он не обеспечивает эффективной комплексной очистки реальных сточных вод, содержащих такие компоненты как ПАВ.A known method of wastewater treatment from dyes by coagulation using as an organic coagulant compounds based on polyacrylic acid, of the General formula:
R - (-

H ₂ -

-H where n = 277-347 R - OCH ₂ CH ₂ OH n = 1390-8333 R - SO ₃ H [2]
The disadvantages of this method can be attributed to the fact that it does not provide effective integrated treatment of real wastewater containing components such as surfactants.

- [-CH₂-

(C₂H₄-NH)₂-A]_n где А-Н или -CH₂-

где R - углеродный радикал с числом углеводородных атомов 8-12 n = 1-2, Х - анионит кислоты, и в качестве минеральной добавки бентонита, суспензированного в растворе ПАВ [3].Closest to the invention in technical essence and the achieved result is a method of wastewater treatment from mixtures of surfactants and dyes, including the introduction of an organic coagulant of the general formula:

- [-CH ₂ -

(C ₂ H ₄ -NH) ₂ -A] _n where A — H or —CH ₂ -

where R is a carbon radical with the number of hydrocarbon atoms 8-12 n = 1-2, X is an acid anion exchange resin, and as a mineral additive is bentonite suspended in a surfactant solution [3].

 The disadvantages of the method is that its implementation is associated with a high consumption of reagents.

 Reducing the dose of reagents leads to a sharp decrease in the cleaning effect and, in addition, the method is time-consuming.

 The objective of the invention is to increase the degree of purification of water from dyes and surfactants with a low consumption of coagulant and the simplification of the process.

 This goal is achieved by the fact that, as an organic coagulant, a stable fixative-2 is used, which is a condensation product of dicyandiamine with formaldehyde and hexamethylenetetramine in acetic acid, and sodium silicate is introduced as a mineral additive. Sodium silicate is administered 3-10 minutes after administration of the organic coagulant. The coagulant and sodium silicate are administered in ratios of 1: (5-12).

CO-NH₂

используется в легкой промышленности для повышения устойчивости окраски изделий, выпускается промышленностью по ГОСТ 23174-78. Вещество представляет собой сиропообразную жидкость, хорошо растворимую в воде и способную длительно хранится без применения свойств. Его растворы нечувствительны к щелочам и электролитам.Fixer "Sustainable-2", the general formula:

CO-NH ₂

It is used in light industry to increase the color stability of products; it is produced by industry according to GOST 23174-78. The substance is a syrupy liquid that is highly soluble in water and capable of long-term storage without the use of properties. Its solutions are insensitive to alkalis and electrolytes.

 When using the proposed method, it is necessary to observe the sequence of the introduction of the reagents, the time gap and the ratio of doses.

 Wastewater is treated with an organic coagulant and sodium silicate, taken in ratios of 1: (5-12), respectively.

 A decrease in the dose of sodium silicate leads to a decrease in the cleaning effect, and an increase above 1:12 does not give a significant improvement in the complexation of contaminants, but leads to a sharp increase in the pH of the treated water and its enrichment with silicate (see Table 1).

 In addition, sodium silicate should be administered 3-10 minutes after the introduction of the coagulant. Reducing the time gap between the introduction of reagents worsens the results of the process of water purification from surfactants and dyes, increasing the time of a gap of more than 15 minutes does not significantly improve the quality of purified water and leads to a significant increase in the volume of water treatment facilities.

 In light industry, the “Sustainable-2” fixer is used to increase the stability of the products' coloring to wet treatments (washing, soap, sweat, etc.).

 In the proposed method, the “Sustainable-2” fixer, when interacting with dye molecules and sodium silicate dissolved in water, forms an organic complex with a developed sorption surface, capable of rapid coagulation, which ensures the speed and efficiency of the process of water purification from surfactants and dyes with a low consumption of coagulant.

 The method is as follows.

 Wastewater containing surfactants and dyes is treated with the above organic coagulant. The dose of coagulant depends on the concentration of surfactants and dyes in water; it is selected experimentally by trial coagulation.

 3-10 minutes after the coagulant is added, sodium silicate is added (see table 2). The dose of sodium silicate should be 5-12 times higher than the dose of coagulant (see table. 1). The wastewater treatment process takes 10-40 minutes. The resulting precipitate is flocculent, light can be removed by flotation, sedimentation, filtration.

 PRI me R 1. Into wastewater of dyeing and finishing production with an initial concentration of surfactant of 120 mg / l and dyes characterized by a color at a dilution threshold of 1: 120, an organic coagulant is introduced in an amount of 30 mg / l. The reaction mixture is subjected to stirring for 5 minutes, then sodium silicate is introduced in the proportions 1: 3, 1: 5, 1: 7, 1:10, 1:12, 1:15 to the coagulant dose, which is 90, 150, 210, 300, 360, 450 mg / l. A suspension resulting from the interaction of introduced reagents and water pollution after 5 minutes is removed from the solution by filtration. After filtering in solutions, the residual surfactant content is determined by the photocolorimetric method and the dye content by the limiting dilution method.

 The process is carried out at ordinary temperature and normal pressure without adjusting the pH. The results are presented in table 1.

 PRI me R 2. According to the conditions of example 1 for the ratio of doses of reagents 1: 7, wastewater treatment was carried out with the following values of the time between the introduction of organic coagulant and sodium silicate: 1, 3, 5, 8, 10, 12 minutes The results obtained are presented in table.2.

 PRI me R 3. Purification is subjected to a model solution containing the following classes of dyes: direct orange 5k 15 mg / l, active bright red 6CX, dispersed yellow strong 2k 15 mg / l, with a color intensity at a dilution of 1: 5000. Organic coagulant is administered in an amount of 60 mg / l, sodium silicate in an amount of 420 mg / l. After separation of the precipitate, the color intensity for dilution was 1: 5.

 From the above data it can be seen that the proposed method allows to increase the effect of wastewater treatment compared to the known method by 36% for surfactants with the same reagent consumption (see table 1) and to reduce the reagent consumption by 570 mg / l for the same degree of water purification commercial product.

 In addition, the interval between the introduction of reagents into the water and filtering the water according to the prototype reaches 3 hours, while the proposed method reduces it to 10-40 minutes, which, in turn, can significantly reduce the volume of treatment facilities.

Claims (3)

 1. METHOD FOR SEWAGE TREATMENT FROM DYES AND SURFACE-ACTIVE SUBSTANCES, including the introduction of an organic coagulant and a mineral additive, characterized in that the product is a condensation product of dicyandiamine with formaldehyde and hexamethylenetetramic acid in a medium containing hexamethylenetetramate acid in a medium containing hexamethylenetetramate acid and sodium.  2. The method according to claim 1, characterized in that the sodium silicate is administered 3 to 10 minutes after the introduction of the organic coagulant.  3. The method according to claim 1, characterized in that the organic coagulant and sodium silicate are introduced in a ratio of 1: 5 to 12.

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