Co/g-C_(3)N_(4)复合催化剂活化过一硫酸盐高效去除环丙沙星的性能研究

Performance of Co/g-C_(3)N_(4)composite catalyst activated peroxymonosulfate in removing ciprofloxacin

以三聚氰胺、三聚氰酸和硝酸钴为原料,采用高温煅烧法制备出复合型催化剂(Co/g-C_(3)N_(4)),用其活化过一硫酸盐(PMS)降解环丙沙星(CIP)。考察了各因素对Co/g-C_(3)N_(4)活化PMS去除CIP的影响。结果表明,Co/g-C_(3)N_(4)质量浓度为0.5 g/L、PMS浓度为2 mmol/L、溶液初始pH为7、CIP初始质量浓度为5 mg/L、温度为30℃时,CIP在45 min内的去除率可达99.5%;催化剂在5次循环利用后对CIP的去除率仍有83.3%,表明Co/g-C_(3)N_(4)的可重复利用性和稳定性良好。自由基淬灭试验表明,Co/g-C_(3)N_(4)活化PMS去除CIP的机制包括自由基途径(SO_(4)·^(-)、·OH)和非自由基途径(^(1)O_(2)、O_(2)·(-),其中主要活性物质为^(1)O_(2),其次为SO_(4)·^(-)。

Co/g-C_(3)N_(4),a composite catalyst,is prepared from melamine,cyanuric acid and cobalt nitrate through high temperature calcination method,and is used to activate peroxymonosulfate(PMS)to degrade ciprofloxacin.The effects of each influencing factor on the removal of ciprofloxacin by Co/g-C_(3)N_(4)activated PMS are investigated.It is shown that the removal rate of ciprofloxacin can reach 99.5%in 45 min when the concentration of Co/g-C_(3)N_(4)added is 0.5 g·L^(-1),the dosage of PMS is 2 mmol·L^(-1),the initial pH of solution is 7,the initial concentration of ciprofloxacin is 5 mg·L^(-1),and T=30℃.The removal rate of ciprofloxacin reaches still 83.3%after the catalyst has been reused for five cycles,indicating that the catalyst has a good reuse performance and stability.It is verified through free radical quenching assay that the mechanism in removing ciprofloxacin by Co/g-C_(3)N_(4)activated PMS includes free radical pathway(SO_(4)·^(-),·OH)and non-free radical pathway(1O_(2),O_(2)·^(-)),in which 1O_(2)is the main active substance,followed by SO_(4)·^(-).