A METHOD FOR RECOVERY OF VAL-DYES FORM THE EFFLUENT CONTAINING VAT DYES

摘要

The present invention describes a method of recovery of vat dye, particularly indigo dye, from the effluents of vat dyeing processes. The method/process of recovery of indigo dye involves treatment of effluents with aqueous solution of copolymers comprising of a mixture of acrylamide and dimethyl aminoethyl methacrylate for 15-60 min; separation of copolymer dye complex from effluents; reduction of copolymer dye complex with a reducing agent such as "Rongalite C" for 4-7 h and subsequent solubilization with caustic hydro solution for release of indigo dye for recycle/reuse in textile industry. Indigo dye recovered by this process is 80%. Further the present invention also describes a method for safe disposal of the residual effluent wherein the copolymer dye complex has been separated. This process involves the treatment of effluent with hydrogen peroxide. This results in 90-95% reduction color intensity, which is suitable for direct disposal. This invention also brings forth the use of aqueous solution of safe copolymers for treatment of effluents for recovery of vat dyes particularly indigo dye, which has extensive application in denim industry. No biological material is being employed.