Abstract: A series of pelletized supports mainly consisting of CeO2 were developed by the traditional molding method and new molding method. Ruthenium catalysts loaded on these supports were prepared by impregnation. The analysis of BET surface area and mechanical strength of the catalysts were carried out. Their activity in wet air oxidation of acetic acid and the stability of Ru/ZrO2-CeO2 in wet air oxidation of phenol were investigated. Ruthenium catalysts prepared by the new method possess larger surface area than that prepared by the traditional method. Introduction of Zr into Ru/CeO2 can increase surface area of the catalyst. In a batch experiment of wet air oxidation of acetic acid with pelletized Ru/ZrO2-CeO2, chemical oxygen demand (COD) removal was 98%. In the dynamic experiment of wet air oxidation of phenol with pelletized Ru/ZrO2-CeO2, phenol and COD reduction was maintained at 96% during 110 h of reaction. The concentration of the main intermediates was small. In the experiment of catalytic wet air oxidation of phenol, the leaching concentration of active species was small. There were small amounts of carbonaceous deposits on the surface of the used catalysts, and the carbonaceous deposits can be completely oxidized at 300 ℃. Pelletized Ru/ZrO2-CeO2 possesses good stability and possibility of use in practical processes.

Key words: ruthenium, ceria, zirconia, supported catalyst, catalytic wet air oxidation, acetic acid, phenol, stability