Catalytic wet air oxidation of phenol aqueous solutions by 1% Ru/CeO2–Al2O3 catalysts prepared by different methods

The wet air oxidation of phenol aqueous solutions (5 g/L) has been studied in a trickle bed reactor (140 °C and 7 atm of oxygen pressure). The experiments were performed over several 1%Ru/5%CeO2–Al2O3 samples, prepared by different methods: impregnation, co-impregnation, co-precipitation and surfactant. Phenol conversion and chemical oxygen demand were evaluated. Results indicate that performance of the catalysts is influenced by the preparation method. Phenol conversions diminished with reaction time; deactivation was attributed to the deposition of carbonaceous solids on the surface and to the transformation of the support into boehmite phase. The selectivity toward CO2 production was, in all cases, nearly complete.