Photodegradation of halogenated organic pollutants in wastewater: A review

Abstract

Halogenated organic pollutants (HOPs) are commonly detected in different water environments and pose a great threat to aquatic species and human health. Photocatalytic technology shows promising prospects in degrading HOPs in wastewater due to the advantages of economical and environment-friendly. Unfortunately, there is rare systematic review about photocatalytic degradation of HOPs. It’s worth noting that photocatalysts are the core determining activity. Therefore, we first summarized the different microenvironmental regulation methods to modify photocatalysts. We then discussed their applications in the photocatalytic degradation of different types of HOPs. In addition, a number of influencing factors for practical applications were also discussed, including catalyst stability, pre-adsorption process and reaction conditions. More importantly, this work summarized and analyzed the degradation mechanisms and pathways of HOPs on the surface of photoexcited catalysts by combining calculation and experiment. The photodegradation process of PFOA is mainly divided into photo-oxidation and photo-reduction pathways. In contrast, chlorophenols and PBDEs are dominated by photo-oxidation and photo-reduction processes, respectively. This comprehensive review not only contributes to the deep understanding of photocatalytic degradation of HOPs in wastewater, but also provides guidance for advancing research in this critical area.