Cu–MnO<i><sub>X</sub></i>/γ-Al<sub>2</sub>O<sub>3</sub> Catalyzed Ozonation of Nitrobenzene in a High-Gravity Rotating Packed Bed
Shengjuan Shao, Lei Du, Yao Song, Lina Liang, Youzhi Liu, Weizhou Jiao
Abstract
In this study, Cu–MnOX/γ-Al2O3 catalyst was first used for heterogeneous catalytic ozonation of nitrobenzene (NB) in a high-gravity rotating packed bed (RPB), as RPB could significantly improve the mass transfer of ozone and thus contribute to the utilization efficiency of ozone and the degradation of NB. To illuminate the synergistic effect of RPB and heterogeneous catalytic ozonation, the degradation (ηNB) and mineralization (ηTOC) efficiency of NB as well as the utilization efficiency of ozone (Ru) in the RPB/O3, BR/O3 (bubbling reactor), and RPB/O3/Cat. processes were compared. The results showed that the ηNB and Ru of the RPB/O3 system were more than twice compared to that of the BR/O3 system due to the high mass transfer of ozone in the RPB. The use of Cu–MnOX/γ-Al2O3 catalyst as a packing in the RPB/O3/Cat. system resulted in an increase in the mineralization of NB from 60.3 to 81.7%. Radical quenching tests confirmed that O2•– and •OH were dominant reactive oxygen species, and O2•– played an important role in •OH generation. In conclusion, Cu–MnOX/γ-Al2O3-catalyzed ozonation and high gravity had a synergistic effect on •OH initiation and thus improved the degradation and mineralization of NB in an aqueous solution.