Key role of •O2- in promoting deep degradation of VOCs in VUV-based process

Abstract

VUV photolysis presents a simple process for VOCs degradation, while the poor mineralization rate and extensive by-products greatly limit its application. In this study, the contribution and synergy between •OH and •O₂^- to toluene degradation in the VUV-based process were comprehensively investigated by controlling water and oxygen in the gas flow. It was found that •OH promoted the initial degradation of toluene and macromolecular intermediates, while •O₂^- dominated toluene mineralization by boosting the formation of small molecules and CO₂. Compared with the •OH-dominated VUV photolysis, the presence of catalyst greatly changed the degradation pathway, promoted toluene mineralization into CO₂ and reduced health toxicity via promoting •O₂^- formation. This study originally focuses on the key role of •O₂^- in VOCs deep oxidation and provides an effective strategy to boost its clean mineralization via the VUV-based process.

Keywords: Deep degradation; Degradation pathways; Synergistic effect; VOCs; VUV-based process; •OH and •O(2)(−).