Abstract
The coagulation behaviors of two widely used model clay particles, kaolin and bentonite were investigated by using ferric chloride as coagulant in this paper. Through experiment, the effects of their suspension concentrations, alkalinity and charge properties on the coagulation behaviors were discussed. The results presented in this paper demonstrated that bentonite possesses very large negative surface charge comparing with kaolin particles. This determined its coagulation behavior shows great difference with that of kaolin. Initial colloid charge and alkalinity of raw water are regarded to be the most important factors influencing coagulant dosage. Eventually, using these two parameters, a formula was proposed for coagulant dosage control for the first time. Optimal dosage estimated by the formula showed a high correlation with jar-test data.
