Preliminary kinetic study on the degradation of nitrobenzene by modified ceramic honeycomb-catalytic ozonation in aqueous solution

Abstract

The kinetics of degradation of nitrobenzene in aqueous solution was investigated in the processes of ozone alone, ozone/ceramic honeycomb (CH), ozone/modified ceramic honeycomb (MCH). The results indicated that all reactions followed the pseudo-first-order kinetic model, and the degradation rate of nitrobenzene was accelerated in the presence of CH or MCH catalyst, and the more pronounced degradation rate was achieved in O 3/MCH system. Under the experimental conditions of reaction temperature 293 K and initial pH 6.87, the rate constants were determined to be 5.21 × 10 −2 min −1 for O 3 alone, 7.99 × 10 −2 min −1 for O 3/CH and 15.45 × 10 −2 min −1 for O 3/MCH. The influencing factors, such as applied ozone concentration (0.987–2.732 mg L −1), initial concentration of nitrobenzene (50–250 μg L −1) and amount of catalyst (0–5 blocks) could yield respectively the positive effect on the pseudo-first-order rate constants for degradation of nitrobenzene in the three processes mentioned above. The results suggested that the modification process promoted the catalytic activity of raw CH catalyst, namely the impregnation of metals (Mn, Cu and K) maybe enhance the initiation of hydroxyl radical ( OH).