Coagulation Efficiency and Residual Aluminum Content of Polyaluminum Silicate Chloride in Water Treatment

Abstract

AbstractA series of polyaluminum silicate chlorides (PASC), which have different OH—/Al and Al/Si molar ratios, has been prepared by a copolymerization technique and a composite technique, after which the coagulation efficiency and the residual aluminum content of PASC for water treatment were compared with polyaluminum chloride (PAC) by jar test. The experimental results show that PASC has better coagulation efficiency and lower residual aluminum content than PAC, and the PASC prepared by the copolymerization technique gives a better coagulating effect than that prepared by the composite technique. In addition, the OH—/Al and Al/Si molar ratios have some effect on the coagulation effect and residual aluminum content of PASC in treated water. With increasing OH—/Al molar ratio and decreasing Al/Si molar ratio, the residual turbidity and residual aluminum content in treated water diminishes. The pH of the water sample also affects the residual aluminum content of the water and there is a lower residual aluminum content in the neutral pH range.