Preparation of Starch Modified Flocculants and Research of Sludge Flocculation Capacity after Modification

Starch-graft-acrylamide was synthesized by 60Coγ-rays co-irradiation method.Effects of various reaction conditions on grafting degree and utilization ratio of acrylamide were studied.The structures of grafted copolymers were characterized by Fourier transform infrared spectroscopy(FT-IR).Results indicated that the optimum synthesis conditions for graft copolymerization were as irradiation dose 15 kGy,mass ratio of starch to acrylamide 0.5∶1,inhibitor to acrylamide mass ratio 0.02%,and acrylamide monomer concentration 5%,with the highest grafting degree as 244%,and utilization ratio of acrylamide as 171%.The grafted copolymers were modified into another sort of cationic flocculants(CSPAM) by Mannich reaction.Experiment results showed that the flocculation effects of excess sludge performed better than commercial PAM and the optimal dosing was less than PAM.