Coagulation performance of Al/Fe based covalently bonded composite coagulants for algae removal

A novel covalently bonded composite coagulant CAFM was synthesized by using inorganic PAFC and organic CPAM through UV initiation. The algae and turbidity removal efficiency were investigated by using CAFM in algae-laden water coagulation process. The Al/Fe residual and algae flocs size were also examined. Results showed that 96% chlorophyll a and 87% turbidity were removed by using CAFM at dosage of 40 mg/L. The removal efficiency was larger than that by using PAFC or CPAM at their optimal dosage. The minimum Al residual of 12.47 μg/L, Fe residual of 9.64 μg/L together with the most compact algae flocs were achieved by using CAFM0.6, which was great favorable and essential for drinking water treatment. Finally, the charge neutralization of PAFC and bridging of CPAM synergetic contributed to algae harvesting.