RU2019522C1 - Process for purifying waste water resulting from dye production - Google Patents

Abstract

FIELD: purification of waste water. SUBSTANCE: waste water is treated with polyelectrolytes and with the addition of copolymers of quaternary ammonium bases in an amount of 0.5-50% based on the concentration of dry matter in waste water. The purification effect is enhanced at a pH 2-12 due to the addition of (co)polymers of quaternary ammonium bases in an amount of 5-25% based on the concentration of dry matter in waste water. The polyelectrolytes include dimethylsulfate polydimethylaminoethyl methacrylate, 1,2-dimethyl-5-vinylpyridium methylsulfate and their monomer-acrylamide copolymers. The process provides high quality purification of dye production multicomponent waste water containing a mixture of dyes of various types and surfactants in the presence of inorganic salts. EFFECT: improved purification process. 2 cl

Description

 The invention relates to methods for treating multicomponent wastewater contaminated with a variety of dyes of different types, in dissolved and dispersed states, as well as surface-active substances (surfactants), salts and other pollutants.

 The closest is a method of treating wastewater from dyes, the essence of which is as follows: 0.001-1 mg / l, 0.2 mg of iron is introduced into wastewater containing a dye (primary bright blue or basic bright green, or purpurine) copper, or vanadium salt of polyacrylic acid (PAA). The reaction mixture in the flask was stirred for 20 minutes. As a result of oxidative degradation, the dye is discolored. The water-insoluble salt of Fe (PAA) or Cu (PAA), or V (PAA) is separated by decantation or filtration. After that, the residual dye content is determined.

 The percentage of cleaning is 100-99.5%. The process is carried out in the presence of hydrogen peroxide at ordinary temperature, normal pressure and pH 6.0-7.3.

 The disadvantages of this method are: loss of dye due to its degradation, pollution of waste water with products of oxidative degradation of the dye, the inability to purify multicomponent water from mixtures of dyes of different nature and surfactants.

 The aim of the invention is the ability to treat wastewater of the dyeing industry, containing mixtures of dyes of various types and surfactants in the presence of inorganic salts.

 A method of treating wastewater based on processing the medium with polyelectrolyte consists in introducing (co) polymers of quaternary ammonium bases in an amount of 0.5-80% of the concentration of dry matter of wastewater.

 In addition, the addition of the method consists in the introduction of (co) polymers in an amount of 5-25% of the concentration of solids at a pH of 2-12. The dose intervals of (co) polymers are determined by the difference in wastewater composition.

To implement the method, a series of measuring cylinders of volumes of 50 ml are simultaneously filled with 50 ml of wastewater from the dyeing industry. Characteristics of wastewater are given in the examples. Then, an aqueous solution of dimethylaminoethyl methacrylate polymer dimethyl sulfate (DMAEMA.DMS) or 1,2-dimethyl-5-vinylpyridinium methyl sulfate (DMVP.MS), or a copolymer of their monomers with acrylamide (DMAEMA.DMS + AA or DMVP) is introduced into each cylinder. . The concentration of the solution of (co) polymer is 0.5 g / dl. The solution is administered in a volume of 0.01-5 ml, which corresponds to a concentration of 1-500 mg / l in the system. After mixing, the system is kept at rest for 20 minutes and the resulting insoluble complexes of dyes, surfactants and (co) polymer are separated by filtration. The absorbance of the filtrate is measured on a spectrophotometer at a wavelength (λ _max ) corresponding to the absorption maximum of the original colored wastewater. The value of D is proportional to the residual concentration of dyes. The dependence of the degree of purification on the concentration of (co) polymer, expressed as a graph or table, is used to determine the optimal concentration of (co) polymer, i.e. minimum concentration, the introduction of which provides the maximum degree of purification (see table. 1). The surfactant content before and after purification is determined by the traditional method.

 Group of examples N 1.

In a series of cylinders with a capacity of 50 ml, 50 ml of wastewater is poured, which has a pH of 7 and contains a mixture of dyes: five straight and one dispersed; a mixture of surfactants: steorox 6, the drug OP-10-4 7, powder "Lotus", DCS; a mixture of inorganic salts: sulfates and chlorides and other auxiliary substances. The concentration of solids is equal to _{C. s.v.} = 0.058 g / dl. Then an aqueous solution of DMAEMA polymer is introduced into them. DMS of a concentration of 0.5 g / dl in an amount of 0.01-5 ml, the systems are mixed, kept at rest for 20 minutes, filtered through a paper filter (white tape) and absorbance is measured filtrate at λ = 540 nm. The dependence of the degree of purification on the polymer concentration (C _p ) is presented in table 1.

 From the data obtained it follows that the clarification effect is observed in a wide range of concentrations of DMAEMA.DMS (3-290 mg / l), which corresponds to an amount of 0.5-50% of the dry matter concentration of wastewater. The optimal concentration range for this polymer is 5–9% of the solids concentration of wastewater. When clarifying wastewater, the optimal polymer concentration surfactants are removed by 80%.

 Group of examples N 2.

In wastewater with a similar composition example to composition at pH 2 and a concentration of solids of _{C. s.v.} = 0.065 g / dl, a 0.5% aqueous solution of DMVP copolymer is added. MS + AA, containing 83 mol% of cationic groups, in the same amounts as in the group of examples 1. The resulting systems were stirred, kept at rest for 20 minutes, filtered and the filtrate D was measured in the same manner as in Examples 1. Wastewater treatment using this copolymer depending on its concentration in the system are given in table.2.

 As can be seen from the above examples, water clarification with pH 2 is observed with the introduction of DMVP copolymer. MS + AA in an amount of 0.5-50% of the solids concentration of wastewater. The effect improves with the introduction of 9-20% of the copolymer of the solids concentration of wastewater. The surfactant content is reduced by 71% (see example 8).

 Group of examples N 3.

 Purify wastewater with a similar composition and the same copolymer as in the examples of group 2, but at pH 1. The process is similar to that at pH 2, however, the high acidity of the medium makes the use of the method impractical.

 Group of examples N 4.

 Wastewater and the copolymer are used similarly to the examples of groups 2 and 3, but at pH 7. The cleaning efficiency of the concentration of the copolymer is given in table.3.

From table 3 it is seen that the clarification process is observed with the introduction of DMVP. MS + AA in an amount of 0.5-50% of the solids concentration of wastewater. The effect is maximum in the range of additions of the copolymer 11-25% of _{C. d.s.} The surfactant content is reduced by 70% (see example 11).

 Group of examples N 5.

 A copolymer and wastewater are used, similar to the group of Examples No. 4. The purification is carried out at pH 12. The dependence of the degree of wastewater treatment on the concentration of DMWP. MS + AA at pH 12 is shown in Table 4.

From the table it follows that with the introduction of DMVP.MS + AA in wastewater with a pH of 12, clarification is observed in the dose range of 0.5-50% of the concentration of solids. The optimal cleaning effect corresponds to an interval of 5-25% of _{C. s.v.} In this case, the surfactant content decreases by 65% (see example 6).

 Group of examples N 6.

 Wastewater with the same composition as in the examples of group 2-5, but with a pH of 13 is purified DMVP. MS + AA (83 mol.% Cationic groups). The process is similar to that at pH 12, however, using this method is impractical due to the aggressiveness of the environment.

 Using the proposed method for wastewater treatment of dyeing plants provides, in comparison with existing methods, the following advantages: the removal of mixtures of dyes of different nature (97-99%) and surfactants (65-80%) in the presence of inorganic salts in a wide pH range while maintaining cleaning quality, reducing the total amount of reagents used, reuse of selected dyes as a pigment for finishing materials, creating a closed cycle of circulating water of the dyeing industry.

Claims (2)

 1. METHOD FOR WASTE WATER CLEANING OF DYE PRODUCTION, including treatment with polyelectrolytes, characterized in that (co) polymers of quaternary ammonium bases selected from the range of: polydimethylaminoethylmethacrylate dimethyl sulfate, 1,2-dimethyl-di-monomethyl-vinylacetate with acrylamide and enter them into the treated water in an amount of 0.5 - 50% of the concentration of dry matter of wastewater.  2. The method according to claim 1, characterized in that (co) quaternary ammonium base polymers are introduced in an amount of 5 to 25% of the solids concentration of the wastewater at pH 2-12.

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