非活化单过硫酸盐降解柳氮磺胺吡啶:动力学及机制

Non-activated Peroxymonosulfate-Induced Degradation of Sulfasalazine: Kinetics and Mechanism Investigations

基于硫酸根自由基的活化单过硫酸盐(peroxymonosulfate, PMS)的高级氧化技术已被广泛应用于污染物去除过程,但有关利用PMS直接氧化去除有机污染物的研究尚不充分.本研究系统地考察了柳氮磺胺吡啶(sulfasalazine, SSZ)在PMS直接氧化过程中的降解动力学及降解途径.结果表明,SSZ的降解符合准一级反应动力学规律,增加PMS浓度或提高离子强度能够加快SSZ的降解速率;碱性条件有利于反应进行;Cl^-的存在显著促进了SSZ的降解;地表水会抑制SSZ的降解.通过质谱分析及活性位点鉴定,推测羟基化和SO2基团挤脱反应是氧化的主要途径.本研究为基于非活化PMS去除水中磺胺类抗生素的应用可行性提供了依据.

Sulfate-radical-based advanced oxidation technologies by activation of peroxymonosulfate(PMS) have been widely applied for decontamination of wastewater, although our knowledge on the direct oxidation of organic contaminants by PMS is still limited. In this study, the direct interaction between PMS and sulfasalazine(SSZ), a widely used antibiotic, was investigated systematically, including the reaction kinetics and transformation pathways. The results revealed that SSZ degradation obeyed a pseudo-first-order kinetic model and increasing initial PMS concentration or ionic strength could accelerate the degradation rates;alkaline conditions were beneficial to SSZ removal by PMS;and the presence of Cl^- markedly promoted SSZ decay. The degradation of SSZ by PMS was inhibited in surface water. By using liquid chromatography-mass spectrometry as well as reaction site identification, two different oxidation pathways were proposed, including hydroxylation and SO2 extrusion. The findings obtained in this study could help to evaluate the feasibility of decontamination of sulfonamide antibiotics by non-activated PMS.