【摘要】 以水体中存在的典型抗菌药磺胺二甲嘧啶(sulfamethazine,SMZ)为研究对象,基于紫外/氯(UV/氯)高级氧化方法,研究了SMZ的降解机制与转化路径。SMZ的降解符合拟一级反应动力学,其降解速率随SMZ初始浓度的升高而降低。采用Box-Behnken试验设计以及DOE响应分析,评估了SMZ降解的主要影响因素。结果表明,氯投加量是影响UV/氯降解SMZ速率的主控因素,其次为pH,二者的影响效应值分别为-22.82和12.06,其交互影响作用效应值仅为1.52,表明增加氯投加量或降低pH均对SMZ的降解有促进作用,但二者无明显相互促进或抑制的效果。质谱分析结果显示,SMZ降解过程产生了10种主要转化产物,基于前线轨道理论分析,明确了SMZ上的7号氮原子(N7)发生羟基和氯原子取代的反应路径,解析了取代产物的二次产物形成机制。更多还原

【Abstract】 The degradation of sulfamethazine(SMZ), a typical antibiotic wildly existing in natural water, by UV/chlorine advanced oxidation process was studied. The degradation of SMZ followed the pseudo first-order kinetic model, and its degradation rate decreased with the increase of initial concentration of SMZ. Main factors contributing to the SMZ degradation were evaluated by Box-Behnken experimental design and DOE-response surface analysis. The results showed that chlorine dosage was the main effect affecting the degradation rate of SMZ by UV/chlorine, followed by pH. The effect values of chlorine and pH were-22.82 and 12.06, respectively. However, chlorine-pH interaction effect value was only 1.52, which indicated that increasing chlorine dosage or lowering pH value promoted the degradation of SMZ but neither has obvious synergistic or antagonistic effect. The results of mass spectrometry detection showed that 10 major products were formed in the degradation process of SMZ. According to the frontier orbital theory, the substitution reaction pathway of hydroxyl and chlorine atoms at N7 was observed in the oxidation and chlorine oxidation of SMZ. Mechanism of the formation of secondary products was explained.更多还原