Application of the extended DLVO approach to mechanistically study the algal flocculation

The extended DLVO theory was applied to study the mechanism of algal flocculation with clays. Montmorillonite-K10, montmorillonite-KSF, kaolinite, and loess were used as the model clays whereas Microcystis sp. and Prorocentrum minimum were used as the model freshwater algae and marine algae, respectively. Montmorillonite-KSF showed the highest flocculation efficiency not only for Microcystis sp. especially at pH 7 but also for P. minimum. From the application of the extended DLVO theory, the electrostatic and the Lewis acid–base interactions were found to be the dominant mechanisms for the flocculation of Microcystis sp. in freshwater and P. minimum in seawater, respectively.