Continuous Catalytic Ozonation of Antibiotics Using Mn and Cu Oxides on γ-Al<sub>2</sub>O<sub>3</sub> Pellets in a Micropacked Bed Reactor
Qiang Cao, Fengyan Lou, Na Liu, Jisong Zhang, Lidong Wu
Abstract
Today, the Al2O3-supported catalyst in the heterogeneous catalytic ozonation system attracts attention due to its stable structure and relatively high surface activity. Herein, Mn and Cu oxides loaded on γ-Al2O3 pellets were prepared using an impregnation method to improve the removal efficiency in a micropacked bed reactor (μPBR). The effects of the initial pH, the ratio of O3 to chemical oxygen demand (COD), and HO• scavenger on the catalytic performance were investigated. Experimental results showed that the MnO2/γ-Al2O3 and CuO/γ-Al2O3 catalysts exhibited excellent catalytic performance. The COD removal efficiencies were 86.3% for CuO/Al2O3, 76.9% for MnO2/Al2O3, 71.6% for Al2O3, and 35.8% for ozone alone within 71 s. Compared with those of batch reactors, the apparent degradation rate constant of COD with prepared catalysts in a μPBR increased by 2–3 orders of magnitude. In addition, the CuO/γ-Al2O3 catalyst maintained a relatively stable activity in the continuous flow test for a long time (100 h). Finally, some typical antibiotics were treated by catalytic ozonation in a μPBR. The removal efficiencies of these antibiotics and COD reached approximately 100.0% and 62.9–87.8% within 71 s, respectively. Thus, the continuous catalytic ozonation system with the CuO/γ-Al2O3 catalyst based on μPBRs could be a promising pathway for the treatment of industrial wastewater with antibiotics.