Abstract
The performance of supported catalysts is significantly affected by the dispersion degree of the active components on the support.In this study,citric acid(CA)was used as a modifier to prepare Al2O3 supported Mn-Ce oxides(Mn-Ce/CA-Al2O3)by the impregnation-calcination method.The characteriza-tion results showed that adding citric acid enhanced the dispersion of Mn-Ce oxides on the support,rendering Mn-Ce/CA-Al2O3 with a larger specific surface area and abundant surface hydroxyl groups,thereby providing more reaction sites for catalytic ozonation.The Mn-Ce/CA-Al2O3 exhibited excellent catalytic ozonation performance in degrading Reactive Black 5(RB5)dye.It achieved nearly complete decolorization of RB5 within 60 min,with a COD removal efficiency of 60％,which was superior to the sole ozonation(30％).Furthermore,the Mn-Ce/CA-Al2O3 system demonstrated significant degradation of RB5 over a wide pH range of 3-11.Based on the XPS and EPR analysis results,a preliminary mechanism of catalytic ozonation over the Mn-Ce/CA-Al2O3 was proposed.The redox cycle of Mn3+/Mn4+and Ce3+/Ce4+effectively accelerated the electron transfer process,thus promoting the generation of reactive oxygen species(ROS)and improving the degradation of RB5.Meanwhile,the Mn-Ce/CA-Al2O3 exhibited superior catalytic stability and effective treatment capabilities for real dve wastewater.
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