Catalytic ozone oxidation of chemical RO membrane concentrate wastewater by a Cu-Ce@γ-Al2O3 ozone catalyst.

Abstract

A Cu-Ce@γ-Al₂O₃ catalyst was developed for the efficient treatment of chemical reverse osmosis (RO) membrane concentrate wastewater. The working conditions and reaction mechanisms of Cu-Ce@γ-Al₂O₃ catalytic ozonation were systematically investigated, and its application in the catalytic ozonation of chemical RO membrane concentrate wastewater was explored. The catalyst was comprehensively characterized using scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), and Fourier-transform infrared (FTIR) spectroscopy, revealing its microstructure, elemental composition, and crystal structure. The optimal reaction conditions were identified as follows: ozone dosage of 8 mg/L/min, initial pH of 9.0, catalyst filling ratio of 10%, and a reactor height-to-diameter ratio of 5:1. Under these conditions, the catalytic ozonation achieved a chemical oxygen demand (COD) removal rate of 63.4%. Free-radical quenching experiments confirmed that hydroxyl radicals (·OH) played a dominant role in the catalytic ozonation system. Kinetic analysis revealed that the catalytic ozonation of chemical RO membrane concentrate wastewater with Cu-Ce@γ-Al₂O₃ followed second-order kinetics. The degradation mechanisms of organic matter in the wastewater were further analyzed using ultraviolet-visible (UV-Vis) spectroscopy and three-dimensional fluorescence spectroscopy. Additionally, a weighted rank sum ratio (WRSR) evaluation model was developed to provide a comprehensive assessment of the process performance. PRACTITIONER POINTS: Cu-Ce@γ-Al₂O₃ catalysts with excellent catalytic performance were prepared. Efficient catalytic ozonation of chemical RO membrane concentrate with high salinity was realized. Degradation mechanism of organic pollutants by catalytic ozonation is clarified. Evaluation model for catalytic ozonation of chemical RO membrane concentrate was established.