Heterogeneous Photocatalytic Activation of Persulfate for the Removal of Organic Contaminants in Water: A Critical Review

Heterogeneous photocatalytic persulfate (PS) activation technologies are being intensively studied for water treatment due to their friendly environmental benefits and photosynergistic effect in comparison with traditional PS activation systems. Previous reviews have summarized diverse PS activation methods and the role of light in the photocatalytic PS activation systems, but it is still urgent to provide a comprehensive review on the deep understanding and rational design of heterogeneous photocatalytic PS-based advanced oxidation processes (AOPs). This review intends to thoroughly address the in-depth fundamentals and mechanisms for the heterogeneous photocatalytic PS-AOPs. Challenges and improvement strategies of the heterogeneous photocatalytic PS-AOPs are also critically discussed. On the basis of a detailed survey of the published studies, heterogeneous photocatalytic PS-AOPs, including Fe-based, TiO2-based, other metal based, bimetallic, and metal-free PS-AOPs, are carefully clarified. Finally, the engineering implications and prospects are enumerated for developing efficient and environmentally friendly heterogeneous photocatalytic PS-AOPs for water treatment. It is expected that this review will motivate researchers to construct novel and promising heterogeneous photocatalytic PS-AOPs for water treatment.