What is the role of light in persulfate-based advanced oxidation for water treatment?

Persulfate-based advanced oxidation processes (PS-based AOPs) under UV, visible, or solar irradiation are being intensively investigated for water treatment. Tremendous advances have been made for enhancing the performance towards the destruction of target pollutants, but a deeper understanding of the role of light in different photo-activated PS-based AOPs is still needed as a basis for improving the efficiency. This paper intends to provide an in-depth review of the underlying photo-activation mechanisms and recent progress in various common photo-activated PS-based AOPs reported over the last decade. Based on a comprehensive survey of previous studies, we categorize these processes according to their reaction mechanisms, including activation by direct UV radiation, processes based on dye-photosensitization, activation through ligand-to-metal charge transfer (LMCT), and photocatalytic processes. Moreover, the improvement in performance of contaminant degradation in these processes compared with those in the absence of light are summarized. Finally, we conclude this review by proposing critical challenges and future perspectives for developing efficient photo-activated PS-based AOPs toward improvement in water treatment and remediation. (C) 2020 Elsevier Ltd. All rights reserved.

Automated summary

Persulfate-based advanced oxidation processes (PS-based AOPs) have shown promising applications in water treatment, but further research is needed to enhance their efficiency; Recent studies on different photo-activation mechanisms have led to significant advancements in the field of PS-based AOPs for water treatment.