Cu/Zn非均相Fenton催化剂的制备及其对环丙沙星的降解效果

Preparation of Cu/Zn heterogeneous Fenton catalyst and its degradation effect of ciprofloxacin

针对传统类Fenton法需在低pH范围内反应的问题,通过正交实验对以铜基为核心Cu/Zn催化剂的化学共沉淀法制备工艺进行了优化,并用XRD、SEM、BET和XPS等测试手段对优选出的催化剂进行了表征;采用单因素分析法考察了优化出的Cu/Zn非均相Fenton催化剂对环丙沙星(CIP)的催化降解效果,并对CIP的催化降解中间产物进行了检测,由此提出了可能的降解路径。结果表明:Cu/Zn金属盐摩尔比是影响Cu/Zn催化剂催化降解CIP的主要因素。优化制备的Cu/Zn催化剂主要组分是CuO,对环丙沙星具有较高的催化活性。在CIP浓度为20 mg·L^(−1)、Cu/Zn催化剂投加量为3.0 g·L^(−1)、H2O2投加量为149.55 mmol·L^(−1)、pH为5.0的条件下,反应90 min时CIP降解率达95.0%。所制备的Cu/Zn非均相Fenton催化剂能在pH为3.0~7.0下保持较好的催化反应活性,且氧化剂H2O2在反应体系中可达86.0%的利用率。Cu/Zn催化剂具有良好的稳定性和较低的金属离子浸出浓度。通过LC-MS分析,检测出了CIP的4种催化降解中间产物,并且发现CIP是从·OH攻击哌嗪环开始降解的。以上结果可为进一步探索Cu/Zn非均相芬顿催化剂降解其他类似目标污染物性能影响提供参考。

Aiming at the problem of the traditional Fenton reaction occurringwithin the low pH range,the preparation process of the chemical coprecipitation method using copper as the core Cu/Zn catalyst was optimized through orthogonal experiments,and the optimized catalyst was characterized by XRD,SEM,BET and XPS.The degradation effect of ciprofloxacin(CIP)by this Cu/Zn heterogeneous Fenton catalyst was investigated through the single factor analysis,the corresponding catalytic degradation intermediates of CIP were detected and the possible degradation pathways were proposed.The experimental results showed that the molar ratio of Cu/Zn metal salt was the major factor affecting the catalytic degradation of CIP by the Cu/Zn catalyst.The main component of the optimized Cu/Zn catalyst was CuO with high catalytic activity for CIP.Under the optimal conditions such as catalyst dosage of 3.0 g·L^(−1),H2O2 dosage of 149.55 mol·L^(−1),pH 5.0,the degradation rate of CIP could reach up to 95.0%after 90 min at the CIP initial concentration of 20 mg·L^(−1).The optimized Cu/Zn heterogeneous Fenton catalyst could maintain high catalytic activity at pH 3.0~7.0,and the utilization rate of oxidant H2O2 could reach 86.0%in the reaction system.The Cu/Zn catalyst had a good stability and low leaching concentration of metal ions.Based on LC-MS analysis,the four intermediate products of CIP degradation were detected,and we could infer that the degradation occurred on the piperazine ring of CIP by·OH attack.The result can provide the theoretical basis for further exploring the effect of Cu/Zn heterogeneous Fenton catalyst on the degradation of other similar target pollutants.