Preparation and coagulation performance of hybrid coagulant polyacrylamide-polymeric aluminum ferric chloride

In this study, we synthesized a novel hybrid coagulant, polyacrylamide (PAM)-polymeric aluminum ferric chloride (PAFC), by the polymerization of acrylamide monomer with the redox system (NH4)(2)S2O8-NaHSO3. The factors affecting the PAM-PAFC hybrid coagulant were investigated in an orthogonal experiment. The maximum intrinsic viscosity was observed at an initiator mass fraction of 0.5%, a polymerization temperature of 50 degrees C, a monomer mass fraction of 20%, and a polymerization time of 4h, which were the optimum synthesis parameters. The spatial network structure of the PAM-PAFC hybrid coagulant was graphically determined by scanning electron microscopy. Hybrid PAM-PAFC was adopted to treat the kaolin-humic acid suspension and the synthetic dye wastewater. The effect of the coagulant dosage and pH on the coagulant experiments were examined. The coagulant experiment on the kaolin-humic acid suspension showed that the optimum treatment efficiency was achieved at a coagulants dosage of 0.6mg/L, at which level the turbidity reductions with the inorganic PAFC coagulant, PAM-PAFC composite, and PAM-PAFC hybrid were 95.30%, 95.84%, and 98.38%, respectively. Treatment with the PAM-PAFC hybrid coagulant was also effective in removing Congo Red and Direct Fast Turquoise Blue GL; the color-removal efficiencies for these dyes were higher than 93% and 94%, respectively. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46355.