Catalytic oxidation and AOPs normally require catalysts or chemical oxidants during VOCs degradation, making these processes costly and complex. We herein developed a facile system, VUV photolysis in pure water (VUV/H₂O), for efficient VOCs degradation without auxiliary substances. The performance and mechanism of this system was intensively studied through controlling reaction conditions, detecting intermediates and analyzing reaction process during toluene degradation. Compared with direct VUV photolysis of gaseous toluene (VUV/Gas), the VUV/H₂O system exhibited higher removal efficiency (83%) and mineralization rate (80%) of gaseous toluene bubbled into the system. In addition, no O₃ and gaseous byproducts were detected in the outlet gas stream. The excellent performance of VUV/H₂O was attributed to the generation of more ·OH from the VUV photolysis of water and the continuous degradation of accumulated intermediates dissolved in water. The high CO₂ yield under an air atmosphere demonstrated that the dissolved oxygen in the water was essential for toluene mineralization since it was involved in the ring-fragmentation of toluene. According to various radicals and organic intermediates detected, possible pathway of toluene degradation in the VUV/H₂O system was also proposed, which include OH addition, hydrogen abstraction and isomerization. The water after reaction can be effectively purified by sustaining VUV irradiation. This study presents a facile VUV/H₂O system without auxiliary substances for efficient VOCs degradation and provides an insight into its degradation mechanism.

在VOC降解期间，催化氧化和AOP通常需要催化剂或化学氧化剂，从而使这些过程成本高昂且复杂。我们在此开发了一种简便的系统，即纯水中的VUV光解（VUV / H ₂ O），可在不使用辅助物质的情况下有效地降解VOC。通过控制反应条件，检测中间体和分析甲苯降解过程中的反应过程，对该系统的性能和机理进行了深入研究。与直接VUV光解气态甲苯（VUV / Gas）相比，VUV / H ₂ O系统具有更高的去除效率（83％）和鼓泡进入系统的气态甲苯矿化率（80％）。另外，没有O ₃在出口气流中检测到气态副产物。VUV / H ₂ O的优异性能归因于水的VUV光解产生更多的·OH和溶解在水中的累积中间体不断降解。在空气气氛下高的CO ₂收率表明，水中的溶解氧对于甲苯的矿化是必不可少的，因为它参与了甲苯的环片段化。根据检测到的各种自由基和有机中间体，VUV / H ₂中甲苯降解的可能途径还提出了O体系，包括OH加成，氢提取和异构化。反应后的水可以通过持续进行VUV照射而有效地纯化。这项研究提出了一种简便的VUV / H ₂ O系统，其中没有用于有效VOC降解的辅助物质，并提供了其降解机理的见解。