Chlorine dioxide (ClO₂) has emerged as a promising alternative to free chlorine for water disinfection and/or pre-oxidation due to its reduced yields of chlorinated disinfection byproducts. ClO₂ decomposes to form chlorite (ClO₂⁻), which influences the following advanced oxidation processes (AOPs) for micropollutant abatement in drinking water. This study aims at investigating the effects of ClO₂⁻ on the concentrations of reactive species (e.g., radicals and ozone) and on the formation of chlorate in the UV/chlorine AOP. Results showed that the concentration of ClO^· in the UV/chlorine process remarkably decreased by 98.20–100.00% in the presence of ClO₂⁻ at concentration of 0.1–1.0 mg·L⁻¹ as NaClO₂. The concentrations of HO^· and ozone decreased by 42.71–65.42% and by 22.02–64.31%, respectively, while the concentration of Cl^· was less affected (i.e., 31.00–36.21% reduction). The overall concentrations of the reactive species were differentially impacted by ClO₂⁻’s multiple roles in the process. UV photolysis of ClO₂⁻ generated HO^· but not Cl^·, ClO^· or ozone under the drinking water relevant conditions. ClO₂⁻ also competed with chlorine for UV photons but this effect was minor (< 1.0%). The radicals/ozone scavenging by ClO₂⁻ outcompeted the above two to lead to the overall decreasing concentrations of the reactive species, in consistency with the kinetic model predicted trends. ClO₂⁻ reacted with radicals and ozone to form chlorate (ClO₃⁻) but not perchlorate (ClO₄⁻). HO^· played a dominant role in ClO₃⁻ formation. The findings improved the fundamental understanding on micropollutant abatement and inorganic byproduct formation by the UV/chlorine process and other AOPs in ClO₂⁻-containing water.

由于二氧化氯（ClO ₂）降低了氯化消毒副产物的收率，因此已成为水消毒和/或预氧化中游离氯的有前途的替代品。CLO _2层分解形成氯酸钠（CLO ₂ ^- ），这影响饮用水下列高级氧化处理（高级氧化）为微量污染物消减。这项研究的目的是调查CLO的影响₂ ^-上的反应性物质（例如，自由基和臭氧）的浓度和在UV /氯AOP形成氯酸盐。结果表明，CLO的浓度^•在UV /氯处理显着地CLO的存在减少了98.20-100.00％₂ ^-浓度为0.1–1.0 mg•L ^-1的NaClO ₂。HO ^•和臭氧的浓度分别降低了42.71–65.42％和22.02–64.31％，而Cl ^•的影响较小（即降低了31.00–36.21％）。所述反应性物质的总浓度被差异通过CLO影响₂ ^-的在此过程中多个角色。在饮用水相关条件下，ClO ₂ ^−的紫外线光解会生成HO ^•，但不会生成Cl ^•，ClO ^•或臭氧。CLO ₂ ^-也与氯竞争紫外线光子，但这种影响很小（<1.0％）。通过CLO基团/臭氧清除₂ ^- outcompeted上述两个导致所述反应性物质的总浓度降低，在一致性与动力学模型预测的趋势。CLO ₂ ^-与自由基和臭氧形式氯酸盐反应（CLO ₃ ^- ），但不高氯酸盐（CLO ₄ ^- ）。HO ^•在CLO起主导作用₃ ^-形成。这些发现通过在CLO的UV /氯处理等的AOP改善上微量污染物减少和无机副产物形成基本理解₂ ^-含水。