Preparation of PVP-DDF flocculant and its dye decolorization performance

Abstract

To solve the problems that cationic flocculant dicyandiamide formaldehyde (DDF) has small floc, high turbidity of effluent and complicated and time-consuming operation process of ordinary modified DDF method when treating anionic dye wastewater, a kind of PVP-DDF flocculant with high molecular weight which can be grafted quickly was prepared by microwave method with polyvinylpyrrolidone (PVP) as graft, DDF as matrix and ceric ammonium nitrate (CAN) as initiator. The removal effects of congo red, reactive brilliant yellow K-6G and acid blue 9 by flocculants prepared under different dosage of DDF and CAN were analyzed. The results show that when the mass ratio of PVP∶CAN∶DDF was 1∶0.3∶15, the decolorization performance of flocculants was the best. Under the optimum conditions, the decolorization rates of Congo red, reactive brilliant yellow K-6G and acid blue 9 simulated printing and dyeing wastewater with concentration of 20 mg/L by PVP-DDF flocculant were 94.93%, 91.12% and 85.87% respectively. The turbidity values are as low as 5.94 NTU, 5.94 NTU and 5.74 NTU, respectively. PVP-DDF flocculant has a large molecular weight, has a good decolorization effect on anionic dye wastewater, and can effectively reduce the turbidity of effluent.

Keywords

• anionic dye decolorization
• dicyandiamide formaldehyde
• polyvinylpyrrolidone
• flocculant
• graft modification