Electrostatic charges on microalgae surface: Mechanism and applications

Electrostatic charging on microalgae surface is a complex phenomenon which is influenced both by the algae’s living activities and their surrounding environments. While the surface charge character property had been long discovered, clearly understanding of its charging mechanism is still challenging. Despite of its complexity, the property of electrostatic charge on algae surface has been widely utilized, for example, for algae separation or harvesting. In this paper, the mechanisms of algae surface charging including Donnan potential or surface potential, and its influencing factors such as pH, ionic strength, microalgae species and growth conditions was reviewed firstly. Meanwhile, the Zeta potential value of microalgae under different conditions are summarized. Focus is then given to the latest development of the applications of surface charges such as flocculation, flotation, coagulation and electrophoretic separation. The challenges and potential research directions on algae surface charging in the future are also outlined. This work provides some insights on the roles of electrostatic charges on microalgae surface, especially on influence factors and mechanisms. • Physiochemical characteristics of algae surface were reviewed. • mechanisms of Donnan potential or surface potential on algae were summarized. • Zeta potential value of microalgae at different conditions were discussed. • Application of surface charges in algae separation harvesting has been reviewed. • Potential research direction on algae surface charging technology was prospected.