复合催化剂S-CuCo_(2)O_(4)的制备及其活化PMS降解CIP性能研究

Preparation of S-CuCo_(2)O_(4)Composite Catalysts and Study on Its Performance of Activating Peroxymonosulfate to Degrade Ciprofloxacin

采用水热法,以硫脲为硫源对CuCo_(2)O_(4)进行硫化处理合成S-CuCo_(2)O_(4),对复合催化剂S-CuCo_(2)O_(4)进行XRD、FT-IR、SEM、XPS、ICP-OES、EPR表征,并考察其活化过一硫酸盐(PMS)降解环丙沙星(ciprofloxacin,CIP)的效果。实验结果表明:成功制备出S-CuCo_(2)O_(4)催化剂,在其表面富含Co(Ⅱ)和Cu(Ⅰ);当催化剂投加量为0.06 g/L、PMS投加量为0.2 g/L、pH=6.4时,复合催化剂S-CuCo_(2)O_(4)在25 min后对CIP的降解效率可达96.8%,降解效果明显优于CuCo_(2)O_(4)、CuCo_(2)S_(4)。自由基淬灭实验和EPR测试表明,SO_(4)^(-)·和^(1)O_(2)是反应体系的主要活性氧物种,其可能的催化机理是:Cu(Ⅰ)和Co(Ⅱ)能直接与PMS反应生成自由基,同时Cu(Ⅰ)能还原Co(Ⅲ)生成Co(Ⅱ),促进Co(Ⅱ)/Co(Ⅲ)循环,催化剂表面存在的氧空位也可与PMS反应生成^(1)O_(2),在活性氧物种的共同作用下CIP被高效降解。复合催化剂S-CuCo_(2)O_(4)在4次循环使用后对CIP的降解效率仍可达93.5%,证明其循环稳定性较好;对其他污染物也有较好的降解效率,具有较好的通用性,在废水处理中具有良好的应用前景。

S-CuCo_(2)O_(4)was prepared by using thiourea as sulfur source to vulcanize CuCo_(2)O_(4)via a simple hydrothermal method.The composite catalyst S-CuCo_(2)O_(4)was characterized by XRD,FT-IR,SEM,XPS,ICP-OES and EPR,and the degradation effect of ciprofloxacin by activating PMS was investigated.The experimental results showed that S-CuCo_(2)O_(4)catalyst has been prepared successfully,and its surface is rich in Co(Ⅱ)and Cu(Ⅰ);when the dosage of catalyst was 0.06 g/L,the dosage of PMS was 0.2 g/L and pH was 6.4,the S-CuCo_(2)O_(4)showed superior behavior for degradation of ciprofloxacin with the efficiency as high as 96.8%in 25 min,better than that of CuCo_(2)O_(4)and CuCo_(2)S_(4).Finally,it was proved that SO_(4)^(-)·and^(1)O_(2)were the main reactive oxygen species in the reaction system by free radical quenching experiment and EPR test.The possible catalytic mechanism is as follows:Cu(Ⅰ)and Co(Ⅱ)can react directly with persulfate(PMS)to form free radicals,and Cu(Ⅰ)can reduce Co(Ⅲ)to form Co(Ⅱ),promoting the Co(Ⅱ)/Co(Ⅲ)cycle,the oxygen vacancies on the catalyst surface can also react with PMS to form^(1)O_(2),and ciprofloxacin can be efficiently degraded under the joint action of reactive oxygen species.The degradation efficiency of the compound catalyst S-CuCo_(2)O_(4)for ciprofloxacin was still up to 93.5%after four cycles,which proved that the cyclic stability was good.It also has good degradation efficiency for other pollutants,and excellent generality,suggesting its potential in wastewater treatment.