Preparation of Cationic Polyacrylamide-Grafted Starch Flocculant and its Application in the Treatment of Coal Slurry Wastewater

A cationic polyacrylamide-grafted starch (St-g-CPAM) flocculant for the coal slurry wastewater, was prepared by using corn starch and acrylamide (AM) as monomers, ethylene methyl propenoyl trimethylammonium chloride (DMC) as cationic monomer through solution polymerization. The effects of initiator concentration, reaction temperature, and monomer concentration on percentage of grafting and the grafting efficiency were investigated. The results show that the optimal conditions of the polymerization are as follows: the monomer to substrate ratio of 2.5, AM:DMC ratio of 2:1, potassium persulfate of 3×10-3 mol/L, reaction time of 4h, the reaction temperature of 50°C. The additional dosage of St-g-CPAM is varying between 20 and 30 mg/L to obtain good flocculation capability