Is commonly used in treatment of wastewater by coagulation method, this method is through waste water dosing of coagulants, the instability of colloidal and suspended matter in the water, colliding and agglomeration through the formation of flocs and then separated in the particles out of the water for the purpose of purifying water. Coagulation of the main advantages of project investment, handling a large amount of hydrophobic dye decolorization efficiency is very high; shortcoming is the need to change with changes in water quality and feeding conditions, poor on hydrophilic dye decolorization, COD removal rate is low.
Because dye-wastewater treatment effect is mainly determined by the effectiveness of coagulants, so far for the technology's research focuses on selected on the coagulant. Compound ferrous coagulant +PAM for the cationic dye wastewater COD removal rate of up to 70%. Feng Xionghan, used homemade of composite modified sex expanded run soil on cation dye dyeing wastewater for adsorption flocculation gel characteristics research, results showed that, composite modified sex expanded run soil on cation dye dyeing wastewater has excellent of adsorption performance, to polypropylene phthalocyanine amine for help gel agent can makes bleaching rate up 99.9%,COD removal rate up 93%, sludge settlement than only for 1%~2%, and has settlement fast, and adaptability strong, and operation simple, and costs low, advantages.