Removal mechanism of Microcystis aeruginosa in Fe2+/sodium percarbonate and Fe2+/sodium persulfate advanced oxidation-flocculation system

Abstract Advanced oxidation process (AOPs) can be used for the treatment of Harmful Algal Blooms (HABs). In this study, two systems of Fe 2+ /sodium percarbonate (Fe 2+ /SPC system) and Fe 2+ /sodium persulfate (Fe 2+ /PS system) were established to explore the removal mechanism of Microcystis aeruginosa ( M. aeruginosa ). The results indicated that the Fe 2+ /SPC system catalyzed H 2 O 2 to generate a large amount of • OH for oxidation by Fe 2+ , and formed Fe 3+ to promote the flocculation of M. aeruginosa . The persulfate was activated by Fe 2+ to generate SO 4 • - with super-oxidizing properties, and Fe 3+ was generated to realize the oxidation and flocculation of M. aeruginosa in the Fe 2+ /PS system. Compared with the traditional method in which the pre-oxidation and flocculation processes are carried out separately, the method in this study effectively improves the utilization rate of the flocculant and the removal effect of M. aeruginosa . The absolute value of zeta potential of Fe 2+ /PS system (|ζ| =0.808 mV) was significantly lower than that of Fe 2+ /SPC system (|ζ| =21.4 mV)( P  < 0.05), which indicated that Fe 2+ /PS system was more favorable for the flocculation of M. aeruginosa cells than the Fe 2+ /SPC system.