Activation Of Hydrogen Peroxide By Cu-doped BiFeO₃ Perovskite For Removal Of Organic Pollutants

As a typical advanced oxidation process,Fenton reaction has been extensively investigated to eliminate refractory organic contaminants in wastewater,because it has strong oxidizing ability and non-selectivity.Nevertheless,it suffers from the narrow working p H range and poor catalyst recyclability,which limit its practical application.To overcome these drawbacks,increasing attention has been paid to develop heterogeneous Fenton-like catalysts.However,the catalytic efficiency of heterogeneous Fenton-like catalyst is low due to its difficult transformation of Fe?III?to Fe?II?.Hence,it is significant important to fabricate highly effective heterogeneous Fenton-like catalysts with faster transformation of Fe?III?to Fe?II?for degarading refractory organic pollutants in wastewater.In the present work,BiFeO₃and C u-doped BiFeO₃(BiFe_1-xCu_x O₃,x=0.1,0.2 and 0.3)were prepared with a sol-gel method.Phenol,bisphenol A,4-nitrophenol and atrazine were selected as target pollutants to investigate the catalytic performance and reaction mechanism of catalysts.The main content is as follows:?1?The synthetic catalysts were characterized by SEM,TEM,XRD,FT-IR,TG,BET,ICP and XPS.XRD result revealed BiFeO₃ was prepared with high crystallinity.The characterization of BET uncovered that doping C u into BiFeO ₃ could increase the specific surface area of BiFeO₃.Moreover,the characterizations of XPS,ICP and XRD further indicated that Cu was successfully doped into BiFeO₃.?2?The degradation experiments of selected target pollutants were carried out by using the synthetic heterogeneouse Fento n-like catalysts.Experimental results showed that doping Cu into BiFeO₃ can improve the catalytic performance of BiFe O₃ and BiFe_0.8Cu_0.2O₃performed best among these doping catalysts.Under the optimum reaction conditions:[catalyst]=0.5 g L^-1,[H₂O₂]=15 mM,[pH]=4.0 and[phenol]=10 mg L^-1,91%of phenol was degraded after reaction of 120 min.The pseudo first-order kinetic rate constant of phenol on BiFe_0.8Cu_0.2O₃ was 5 times higher than those of traditional heterogeneous Fenton-like catalysts,such as Fe₃O₄ and goethite.Meanwhile,BiFe_0.8Cu_0.2O₃ has good catalytic performance for degradation of other pollutants.After 120 min of reaction,the degradation efficiency of 4-nitrophenol,BPA and atrazine were 98%,58%and 75%,respectively.The phenol degradation efficiency could still reach 83%after 4 cycles,which implied the good stability of BiFe_0.8Cu_0.2O₃.Moreover,the results of radical quenching and EPR experiments revealed that·OH was the dominant ROS that responsible for the degradation of phenol in reaction system.The XPS results indicated that doping Cu into BiFe O₃ could generate more Fe?II?and improve the catalytic performance of catalysts,which was ascribed to the fact that the standard reduction potential of Fe?III?/Fe?II?was 0.77 V and that of C u?II?/Cu?I?was 0.17V,thus Fe?III?was reduced by Cu?I?and then regenerated more Fe?II?in catalysts.