Influencing mechanism of temperature on the degradation of nitrobenzene in aqueous solution by ceramic honeycomb catalytic ozonation

The heterogeneous catalytic ozonation of nitrobenzene in aqueous solution has been carried out at different reaction temperatures in a semi-continuous batch reactor where ceramic honeycomb has been used as a catalyst. The experimental results indicated that the presence of ceramic honeycomb catalyst significantly improved the degradation efficiency of nitrobenzene compared to the results from non-catalytic ozonation, and the adsorption of nitrobenzene on the catalytic surface has no significant effect on its degradation efficiency. The degradation of nitrobenzene followed the pseudo-first-order kinetic model in both the processes of ozone alone and ozone/ceramic honeycomb. With the increase of reaction temperature from 278 K to 328 K, the degradation efficiency of nitrobenzene, the reaction rate constants, the utilization efficiency of ozone, the formation of hydroxyl radicals ((OH)-O-center dot) and the removal of total organic carbon (TOC) all increased in the process of ozone/ceramic honeycomb. The enhancement of reaction rate constant and the enhancement of (OH)-O-center dot formation exhibited a good correlation in the reaction temperature scope of 278-328 K. (C) 2009 Elsevier B.V. All rights reserved.