Meng Liang, Dong Jiayue, Chen Jing, Lu Junhe, Ji Yuefei
Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China.
Department of Environmental Science and Engineering, Nanjing Agricultural University, Nanjing, 210095, China; State Key Laboratory of Pollution Control and Resources Reuse, Nanjing, 210023, China.
Chemosphere. 2023 Apr;320:137969. doi: 10.1016/j.chemosphere.2023.137969. Epub 2023 Jan 31.
As an environment-friendly oxidant and disinfectant, peracetic acid (PAA) and PAA based-advanced oxidation processes (AOPs) for the treatment of emerging micropollutants have raised increasing interest, owing to their ease of activation and less generation of harmful disinfection byproducts. Tetracyclines (TCs) antibiotics as a group of wide-spectrum antibiotics are frequently detected in sewage effluents, while the knowledge of PAA-based advanced oxidation reactions to remove the substrates is quite limited. In this work, we systematically investigated the kinetics and underlying transformation mechanisms of three TCs including tetracycline (TTC), oxytetracycline (OTC), and chlortetracycline (CTC) in the UV-activated PAA oxidation process. The results indicated that three TCs can be efficiently decayed by UV/PAA. The pseudo-first-order reaction rate constants (k) of TCs followed the order: k (0.453 min) ≫ k (0.164 min) > k (0.158 min). Quenching experiments showed that the removal of CTC was mainly ascribed to the direct oxidation of PAA, while TTC and OTC were more susceptible to free radicals. The k values of the three TCs by PAA oxidation presented a fairly well correlation to the global nucleophilicity and the activation energies of the TC molecules, highlighting the structure-specific reactions of TCs to PAA. Based on product identification and theoretical calculation, N-demethylation and hydroxylation were proposed as the main pathways for TCs degradation by PAA non-radical oxidation. The combination of PAA and UV irradiation can further improve the degradation efficiency of TCs and contribute to reducing the diffusion and transmission of resistance genes in the environment.
作为一种环境友好型氧化剂和消毒剂，过氧乙酸（PAA）以及基于PAA的高级氧化工艺（AOPs）用于处理新兴微污染物已引起越来越多的关注，这是因为它们易于活化且产生的有害消毒副产物较少。四环素（TCs）类抗生素作为一类广谱抗生素，在污水排放物中经常被检测到，然而关于基于PAA的高级氧化反应去除这些底物的知识却相当有限。在这项工作中，我们系统地研究了紫外线活化PAA氧化过程中三种TCs（包括四环素（TTC）、土霉素（OTC）和金霉素（CTC））的动力学及潜在转化机制。结果表明，三种TCs可被UV/PAA有效降解。TCs的准一级反应速率常数（k）顺序为：k（0.453 min⁻¹）≫ k（0.164 min⁻¹）> k（0.158 min⁻¹）。猝灭实验表明，CTC的去除主要归因于PAA的直接氧化，而TTC和OTC更容易受到自由基的影响。三种TCs经PAA氧化的k值与TC分子的全局亲核性和活化能呈现出相当良好的相关性，突出了TCs与PAA反应的结构特异性。基于产物鉴定和理论计算，提出N-去甲基化和羟基化是PAA非自由基氧化降解TCs的主要途径。PAA与紫外线照射相结合可进一步提高TCs的降解效率，并有助于减少环境中抗性基因的扩散和传播。
