Catalytic wet air oxidation of succinic acid over Ru and Pt catalysts supported on CexZr1-xO2 mixed-oxides

摘要

Industrial wastewaters often contain highly concentred, toxic and hazardous pollutants. The Wet Air Oxidation (WAO) is an effective and viable technology for the treatment of such effluents. Ru and Pt catalysts demonstrated high efficiencies and chemical stability in the CWAO of numerous organic compounds. CexZr1-xO2 mixed oxides and CexZr1xO2-supported Ru and Pt catalysts were developed and evaluated in the CWAO of succinic acid (5 g L-1) at 190°C under 50 bar total pressure. CexZr1-xO2 mixed oxides were synthesized by co-precipitation, and Ru and Pt catalysts were prepared via wet impregnation. The bare CexZr1-xO2 mixed oxides already showed some activity in the CWAO of succinic acid, and the activity of the bare CexZr1-xO2 mixed oxides correlated with the Ce content (redox centers): the higher the Ce content, the higher the succinic acid conversion. The 0.5wt.%Pt/CeO2 and 0.5wt.%Pt/Ce0.9Zr0.1O2 catalysts had the better activities in the CWAO of succinic acid and 100% succinic acid conversion was obtained after 180 min reaction only. 0.5wt.%Ru/CexZr1-xO2 catalysts exhibited even better performances in the CWAO of succinic acid than the Pt catalysts. The Ru catalyst activity was also affected by Ce content in the support: succinic acid conversion increased with increasing Ce content in the CexZr1-xO2 mixed oxides. All these results exemplified the impact of the oxygen mobility at the CexZr1xO2 mixed oxide surface on the catalyst performances.