In order to solve the problems of harsh preparation conditions and high dissolution of metal ions in metal-non-metal composites,cobalt and copper co-doped graphitic carbon nitride composites were prepared by the impregnation method and heat condensation polycondensation method.Rhodamine B(RhB)was used as a pollutant to study the performance of the catalyst on activating H2O2 under simulated sunlight and degrading RhB.The physicochemical properties of the catalyst were characterized by XRD,FTIR,XPS and BET.The effects of catalyst dosage,H2O2 concentration,initial pH of solution and coexistence of inorganic anions on the catalytic activation performance were investigated.The results show that Co and Cu existed stably in the composites with the form of Co-N and Cu-N bonds,and the special structure of carbon nitride restricted the dissolution of cobalt and copper metal ions.When the mass ratio of CuCN to CoCN was 0.1,the obtained composite Cu/CoCN(0.1)had the best catalytic performance.Within the initial pH=5.0～12.0 range,Cu/CoCN(0.1)showed a good catalytic activity.At Cu/CoCN(0.1)dosage of 0.25 g·L-1 and H2O2 dosage of 20 mmol·L-1,the degradation rate of RhB was 96.5％in 10 min.The presence of H2PO42-had a certain inhibitory effect on RhB removal,and HCO3-had a promoting effect on RhB removal,while Cl-,SO42-and NO3-had insignificant effects on RhB removal.After 4 cycles of use,the degradation rate of Cu/CoCN(0.1)could still reach 91.2％,and the total dissolution concentrations of Co2+and Cu2+were 0.30 and 0.56 mg·L-1,respectively.Free radical scavenging experiments showed that·OH and ·O2-were the main active species.Through the characterization and analysis of the catalyst and free radical scavenging experiments,the degradation mechanism of RhB by the catalyst was proposed.The results of this study can provide a theoretical reference for the application of heterogeneous Fenton-like technology in the treatment of printing and dyeing wastewater.
bi-metal dopedcompositesphoto-Fentondegradation of Rhodamine B
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