Synthesis and application of cationic flocculant with cassava starch

A novel condensation polymer starch-base cationic polyelectrolyte (S-FAD) was synthesized by grafting a copolymer of formaldehyde, acetone and dimethylamine (FAD) onto cassava starch. S-FAD samples were characterized by FT-IR, XRD and elementary analysis. The optimum synthesis condition was determined by investigating the cationicity and the color removal performance of the cationic starch. Their performance as a cationic flocculant in removing three anionic azo-dyes from simulated dye wastewater was evaluated. Results showed that the optimum conditions were as follows: reaction temperature 65 °C, the mole ratio of formaldehyde to dimethylamine and acetone to dimethylamine were 4 and 1.2 respectively, the dose of starch was 5 g. Under this condition, the cationicity of the product can reach 3.40 mmol/g. The coagulation-flocculation properties were excellent under acidic and neutral conditions and the decolorizing rates were above 98%.