Jiang Meng-di, Zhang Qing-Yue, Ji Yue-Fei, Lu Jun-He
College of Resources & Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Huan Jing Ke Xue. 2018 Apr 8;39(4):1661-1667. doi: 10.13227/j.hjkx.201707201.
Sulfate radical (SO)-based advanced oxidation technologies (SR-AOPs) are widely used for remediation of contaminated groundwater and soils. This study investigated the reaction kinetics, products, and transformation pathways of triclosan, a widely used antimicrobial agent, during its degradation by heat activated persulfate oxidation. Experimental results revealed that increasing temperature or initial persulfate concentration significantly enhanced the degradation of triclosan. The reaction could be fitted in the pseudo-first-order kinetic model and the activation energy () was determined to be 142 kJ·mol. The presence of humic acid markedly inhibited triclosan degradation, whereas chloride (Cl) showed a more complicated effect. Triclosan degradation was slightly accelerated in the presence of 5 μmol·L Cl, however, a higher concentration of Cl (e.g., 10 μmol·L) showed an inhibitory effect. Using liquid chromatography-mass spectrometry, a total of six transformation products, including 4-chlorocatechol, 2,4-dichlorophenol, and 2-chloro-5-(2,4-dichloro-6-hydroxyphenoxy)-1,4-benzoquinone, were identified. Accordingly, the cleavage of the ether bond and hydroxylation of the phenol ring were proposed as the principal pathways of triclosan degradation upon reaction with SO. The findings of this study can be used to evaluate the feasibility of decontamination of triclosan by SR-AOPs.
基于硫酸根自由基（SO）的高级氧化技术（SR-AOPs）被广泛用于受污染地下水和土壤的修复。本研究调查了广泛使用的抗菌剂三氯生在热活化过硫酸盐氧化降解过程中的反应动力学、产物及转化途径。实验结果表明，升高温度或提高过硫酸盐初始浓度均能显著增强三氯生的降解。该反应可拟合为准一级动力学模型，且测定活化能（）为142 kJ·mol。腐殖酸的存在显著抑制三氯生降解，而氯离子（Cl）的影响更为复杂。在5 μmol·L Cl存在下，三氯生降解略有加速，然而，较高浓度的Cl（如10 μmol·L）则表现出抑制作用。通过液相色谱-质谱联用，共鉴定出六种转化产物，包括4-氯邻苯二酚、2,4-二氯苯酚和2-氯-5-(2,4-二氯-6-羟基苯氧基)-1,4-苯醌。据此，提出醚键断裂和酚环羟基化是三氯生与SO反应降解的主要途径。本研究结果可用于评估SR-AOPs对三氯生去污的可行性。
