Jar tests were conducted using synthetic waters containing model colloids and organics to evaluate the coagulation performance of simple FeCl3 and polymeric iron chloride (PICl) having various polymer yield. Coagulation of synthetic model waters with PICls of different hydrolysis ratios was compared to simple ferric chloride under varying conditions of pH and model water concentrations. The use of PICls seemed to produce similar reduction in turbidity and TOC when compared with using FeCl3 as a coagulant under typical range for coagulation; however, treatable region was broadened to lower pHs for coagulation of both model waters. By eliminating the region of restabilization of turbidity at lower pHs, an additional region for coagulation using PICls at pH 5-6 was observed. A conceptual surface charge distribution when using different coagulants was established to explain the restablization observed in this study. The different coagulation behaviors of PICls when compared to simple FeCl3 are probably due to their larger sizes and bearing lower charge density. (C) 2009 Elsevier B.V. All rights reserved.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS