Peng Jiadong, Yin Ran, Yang Xin, Shang Chii
Department of Civil and Environmental Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon 999077, Hong Kong.
School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275, China.
Environ Sci Technol. 2022 Jan 18;56(2):1257-1266. doi: 10.1021/acs.est.1c05133. Epub 2022 Jan 3.
Ultraviolet (UV)-based advanced oxidation processes (AOPs) are increasingly used for the degradation of micropollutants in water and wastewater. This study reports a novel UVA/chlorine dioxide (ClO) AOP based on the photolysis of ClO using energy-efficient UV radiation sources in the UVA range (e.g., UVA-LEDs). At a ClO dosage of 74 μM (5.0 mg L as ClO) and a UV fluence at 47.5 mJ cm, the UVA/ClO AOP generated a spectrum of reactive species, including chlorine oxide radicals (ClO), chlorine atoms (Cl), hydroxyl radicals (HO), and ozone at a concentration of ∼10, ∼10, ∼10, and ∼10 M, respectively. A kinetic model to simulate the reactive species generation in the UVA/ClO AOP was established, validated against the experimental results, and used to predict the pseudo-first-order rate constants and relative contributions of different reactive species to the degradation of 19 micropollutants in the UVA/ClO AOP. Compared to the well-documented UVC/chlorine AOP, the UVA/ClO AOP produced similar levels of reactive species at similar oxidant dosages but was much less pH-dependent and required much lower energy input, with much lower formation of chloro-organic byproducts and marginal formation of chlorite and chlorate.
基于紫外线（UV）的高级氧化工艺（AOPs）越来越多地用于降解水和废水中的微污染物。本研究报道了一种新型的UVA/二氧化氯（ClO₂）AOP，该工艺基于使用UVA范围内的高能效紫外线辐射源（如UVA发光二极管）对ClO₂进行光解。在ClO₂投加量为74 μM（以ClO₂计为5.0 mg/L）且紫外线通量为47.5 mJ/cm²的条件下，UVA/ClO₂ AOP产生了一系列活性物种，包括氧化氯自由基（ClO₂•）、氯原子（Cl•）、羟基自由基（HO•）和臭氧，其浓度分别约为10⁻¹¹、10⁻¹²、10⁻¹³和10⁻¹⁴ M。建立了一个动力学模型来模拟UVA/ClO₂ AOP中活性物种的生成，通过实验结果进行了验证，并用于预测UVA/ClO₂ AOP中不同活性物种对19种微污染物降解的伪一级速率常数和相对贡献。与文献记载较多的UVC/氯AOP相比，UVA/ClO₂ AOP在相似的氧化剂投加量下产生了相似水平的活性物种，但对pH的依赖性小得多，所需的能量输入低得多，氯代有机副产物的生成量低得多，亚氯酸盐和氯酸盐的生成量微乎其微。
