Effect of Precious Metals on the Activity of Multi-Component Supported Catalysts

Abstract

Organic waste-water is treated by catalytic wet oxidation method (CWAO). The catalysts are prepared by the same amount of impregnation method. Fe and Co are used as active components of the catalyst, and Ce is used as the catalytic assistant, and the precious metal Pd is added to prepare a multi-component composite catalysts. When the Pd-based catalyst is added to the waste-water, the pH decreases and then increases. The process of organic matter degradation is first converted to small molecule organic acids, the pH is reduced, and then the small molecule organic acids are gradually decomposed. In the proportion of Pd-catalyst, as the Pd content in the catalyst increases, the treatment effect of the waste-water is enhanced; Effect of different ratios on the stability of Pd-Fe-Co-Ce/FSC catalysts showed that, CODCr removal rate increased from 65.7% to 84.7%, and decolorization rate increased from 72.5% to 97.2%. The average concentration of Pd3+, Fe3+, Co2+ and Ce3+ dissolved is 0.0015, 2.2519, 0.2281 and 0.2300, respectively. The Pd-catalyst Pd-Fe-Co-Ce/FSC with metal ion ratio Pd-Fe-Co-Ce=1:1:1:3 has the highest activity in waste-water treatment, and CODCr removal rates and decolorization rates reach 88.7% and 97.9%, respectively.