双波长紫外线(VUV/UV)对有机污染物强化去除特性与原理

With the development of high-transparency quartz tube wall, amalgam alloy and power supply current technologies, a new dual-wavelength ultraviolet light source that can simultaneously emit 185 nm VUV (Vacuum UV) and 254 nm UV has received extensive attention in the field of water treatment. VUV/UV can directly activate water molecules to generate strongly oxidizing radicals and secondary oxidants such as H₂O₂, enhancing the removal of organic pollutants in water and is a green and environmentally friendly advanced oxidation technology. It has attracted much attention in recent years in the fields of drinking water and sewage reclamation treatment and ultrapure water preparation. To grasp the latest progress and development trends of dual-wavelength ultraviolet light, this paper systematically explains the principle of VUV/UV advanced oxidation, summarizes the research on the degradation of organic pollutants by typical VUV/UV, and deeply discusses the influence laws of pollutant structure and water quality conditions such as pH, anions and dissolved organic matter on the VUV/UV oxidation efficiency. The results show that: ① VUV/UV can directly cleave water molecules to generate strong radicals and can also activate the secondary oxidant H₂O₂ to indirectly generate strongly oxidizing radicals; ② VUV/UV significantly enhances the removal rate of refractory organic pollutants, and the removal rate is 2.0 - 19.3 times that of direct UV photolysis; ③ pH affects the efficiency of VUV/UV generation and utilization of ·OH, changes the chemical form and degradation rate of pollutants, and has an impact on the water quality matrix; ④ Inorganic anions such as nitrate, carbonate and halogens inhibit the degradation efficiency of VUV/UV on pollutants by competing for the absorption of ultraviolet light and consuming strongly oxidizing radicals. As the demand for the removal of refractory and high-risk organic pollutants in drinking water and advanced sewage reclamation treatment in China is continuously increasing, it is urgent to clarify the future research directions of VUV/UV, including researching the direct/indirect oxidation mechanisms of VUV/UV and optimizing the hydraulic flow regime and reactor design.

随着高透石英管壁、汞齐合金和供电电流技术的发展,可同时发射185 nm VUV(Vacuum UV,真空紫外线)和254 nm UV的双波长紫外线新型光源在水处理领域受到广泛关注. VUV/UV可直接活化水分子生成强氧化性自由基和次生氧化剂H_2O_2等,强化水中有机污染物的去除,是一种绿色环保的高级氧化技术,近年来在饮用水和污水再生处理、超纯水制备领域备受关注.为掌握双波长紫外线的最新进展和发展趋势,该文系统说明了VUV/UV高级氧化的原理,总结了典型VUV/UV降解有机污染物的研究,深入讨论了污染物结构及pH、阴离子和溶解性有机物等水质条件对VUV/UV氧化效率的影响规律.结果表明: ①VUV/UV能直接裂解水分子生成强自由基,也能活化次生氧化剂H_2O_2间接生成强氧化性自由基; ②VUV/UV显著强化难降解有机污染物的去除率,去除速率是UV直接光解的2.0~ 19.3倍; ③pH影响VUV/UV生成及利用·OH的效率,改变污染物化学形态和降解速率,对水质基质产生影响; ④硝酸根、碳酸根、卤素等无机阴离子通过竞争吸收紫外线,消耗强氧化性自由基等方式抑制VUV/UV对污染物的降解效率.随着我国在饮用水、污水再生深度处理中对难降解、高风险有机污染物的去除需求不断增加,亟需明确VUV/UV未来的研究方向,包括研究VUV/UV直接/间接氧化机制,优化水力流态和反应器设计等.