Microbial electrochemical systems for hydrogen peroxide synthesis: Critical review of process optimization, prospective environmental applications, and challenges.

Hydrogen peroxide (HO) is an industrial chemical that has been widely adopted for various industrial applications, including water and wastewater treatment. Currently, the majority of HO is being produced through the anthraquinone oxidation process, which is disadvantageous due to the requirement of toxic raw materials and high energy input. Recently, microbial electrochemical cells (MXCs), such as microbial fuel cells and microbial electrolysis cells, have demonstrated great potential for effective HO production via cathodic oxygen-reduction reaction (ORR). Previous studies have specified key operational parameters for scaling-up of HO-producing MXCs, where improvements in production rate, conversion efficiency, product concentration and stability are attainable. Moreover, various systems have demonstrated their value proposition in the contaminant removal aspects through direct removal of various environmental pollutants, water disinfection, and many more. This review is intended to highlight promising ways of HO production with MXCs and on-site environmental applications of bioelectrochemically-produced HO.