非自由基活化过一硫酸盐氧化降解喹啉的反应机制及毒性评价

Degradation mechanism and toxicity evaluation of oxidative removal of quinoline by nonradical-activated peroxymonosulfate

采用非自由基活化的过一硫酸盐(PMS)氧化降解水中的喹啉,考察了PMS浓度、初始pH、反应温度及水中共存物质对喹啉降解效率的影响.结果表明,非自由基活化PMS体系可以有效降解喹啉,喹啉的降解过程符合伪一级反应动力学.初始喹啉浓度为10.0 mg·L^(-1)、PMS浓度为4.0 mmol·L^(-1)、pH为7.0、温度为25℃的条件下,反应150 min喹啉降解率达到95.8%.HCO_(3)^(-)、NO_(3)^(-)、SO_(4)^(2-)和腐殖酸对喹啉的降解没有影响,高浓度Cl-可促进喹啉的降解.淬灭实验证实,反应体系中没有SO_(4)^(-)·和·OH的生成,而存在单线态氧(^(1)O_(2)),PMS的直接氧化是喹啉降解的主导作用机制.通过GC-MS检测了喹啉降解的中间产物,并推测了喹啉降解的可能路径.毒性实验表明,反应体系降解喹啉过程中产生了毒性更强的中间产物,而在最佳反应条件下体系可以有效脱毒.

In this study,nonradical-activated peroxymonosulfate(PMS)system was used for the oxidative removal of quinoline in wastewater.The effects of PMS concentration,initial pH value,reaction temperature,coexisting anions and humic acid on the removal of quinoline were investigated.The results showed that nonradical-activated peroxymonosulfate system could effectively degrade quinoline,and the degradation of quinoline followed the pseudo-first-order kinetics.The degradation rate of quinoline was 95.8%with quinoline initial concentration of 10.0 mg∙L^(-1),PMS concentration of 4.0 mmol·L^(-1),initial pH value of 7.0,reaction temperature of 25℃and reaction time of 150 minutes.NO_(3)^(-),CO_(3)^(2-),SO_(4)^(2-)and humic acid make no effect on the degradation of quinoline,high concentration of Cl-promoted the degradation.Free radical quenching experiments confirmed the inexistence of SO_(4)^(-)·and·OH,and existence of ^(1)O_(2) in the system,in which the direct oxidation of PMS was dominant in the degradation of quinoline.The intermediates were detected by GC-MS,from which pathways for quinoline degradation were inferred.Results of bacteria acute toxicity showed that although more toxic intermediate products may be produced during the degradation of quinoline,the detoxification could be achieved under the optimal operation of the system.