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

ABSTRACT 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)2S2O8–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 °C, a monomer mass fraction of 20%, and a polymerization time of 4 h, 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 0.6 mg/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. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46355.