Nong Yu-Jia, Wu Qian-Yuan, Qin Yuan-Chu, Jing Zi-Bo, Wang Er-Dong, Bai Qing, Wang Wen-Long
Key Laboratory of Microorganism Application and Risk Control of Shenzhen, Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental Safety, Institute of Environment and Ecology, Tsinghua Shenzhen International Graduate School, Tsinghua University, Shenzhen 518055, China.
Environ Sci Technol. 2025 Aug 5;59(30):16011-16020. doi: 10.1021/acs.est.5c04240. Epub 2025 Jul 26.
UV/sulfite technologies offer promising advanced reduction processes (ARPs) for the degradation and dehalogenation of halogenated organic compounds (HOCs), but are limited by the low absorption of sulfite at a conventional wavelength of 254 nm (UV254). This study introduces a wavelength-optimized far-UVC KrCl* lamp (UV222)/sulfite as transformative ARPs. Sulfite exhibited 45.6-fold stronger absorption at 222 nm compared with 254 nm, coupled with a higher innate quantum yield (Φ) of 0.128 mol·Ein versus 0.115 mol·Ein. This wavelength optimization generated 29.2-fold higher steady-state concentration of e, with optimal performance at basic pH (>9) and moderate sulfite dosages (0.4-0.75 mM). HOC degradation and dehalogenation showed clear structure-dependent patterns. The enhancive effect of UV222 over UV254 negatively correlated with HOCs' susceptibility to UV photolysis due to competitive absorption between sulfite and target compounds. Electron-withdrawing halogens significantly favored reductive degradation over oxidation, enabling UV222/sulfite to outperform UV222/HO by 1.3-37.1 times in degradation and 1.9-48.6 times in dehalogenation efficiency, with prominent enhancement particularly for polyhalogenated HOCs. In real water matrices, nitrate and nitrite inhibited HOCs' degradation through UV absorption and e scavenging. Compared with UV254/sulfite, UV222/sulfite reduced energy costs by 92.7% and required lower sulfite doses. This study provides insights into the wavelength-matching mechanism for UV/sulfite, offering an economical and efficient solution for the remediation of recalcitrant HOCs.
紫外线/亚硫酸盐技术为卤代有机化合物（HOCs）的降解和脱卤提供了有前景的高级还原过程（ARPs），但受限于亚硫酸盐在254nm（UV254）传统波长下的低吸收。本研究引入了波长优化的远紫外线氪氯准分子灯（UV222）/亚硫酸盐作为变革性的ARPs。与254nm相比，亚硫酸盐在222nm处的吸收增强了45.6倍，同时具有更高的固有量子产率（Φ），分别为0.128mol·爱因斯坦和0.115mol·爱因斯坦。这种波长优化产生了高29.2倍的稳态电子浓度，在碱性pH（>9）和中等亚硫酸盐剂量（0.4 - 0.75mM）下具有最佳性能。HOC的降解和脱卤呈现出明显的结构依赖性模式。由于亚硫酸盐与目标化合物之间的竞争吸收，UV222相对于UV254的增强效应与HOCs对紫外线光解的敏感性呈负相关。吸电子卤素显著有利于还原降解而非氧化，使得UV222/亚硫酸盐在降解方面比UV222/羟基自由基（HO）性能高1.3 - 37.1倍，在脱卤效率方面高1.9 - 48.6倍，对于多卤代HOCs尤其有显著增强。在实际水体基质中，硝酸盐和亚硝酸盐通过紫外线吸收和电子清除抑制HOCs的降解。与UV254/亚硫酸盐相比，UV222/亚硫酸盐降低了92.7%的能源成本，并需要更低的亚硫酸盐剂量。本研究为紫外线/亚硫酸盐的波长匹配机制提供了见解，为顽固HOCs的修复提供了经济高效的解决方案。
