Catalytic ozone oxidation performance of Fe-Ce@γ-Al2O3 in reverse osmosis concentrate treatment

Abstract

The reverse osmosis concentrate (ROC) produced in the process of textile wastewater treatment has a high salt content, posing a significant environmental threat. In this study, catalytic ozone oxidation was used to treat ROC, which initially had a chemical oxygen demand (COD) of 127.38 mg/L. The Fe-Ce@γ-Al2O3 catalysts had the best performance under the Fe/Ce doping ratio of 3:1, calcination temperature of 500 °C with calcination time of 4 h. SEM and XRD analyses confirmed the successful loading of Fe and Ce on γ-Al2O3. The catalytic ozone oxidation conditions were optimized by the response surface method (RSM). Under the optimal reaction conditions (catalyst dosage of 139.07 g/L, ozone ventilation rate of 1.65 L/min, and initial pH of 9.86), the actual COD removal rate reached 89.21 %. Three-dimensional fluorescence spectroscopy was used to analyze the degradation mechanism of dissolved organic matter (DOM) during the treatment of ROC. Three-dimensional fluorescence spectrum (3DEEM) results demonstrated the obvious degradation of DOM in ROC after the catalytic ozone oxidation treatment. The COD removal rate remained at approximately 80 % after 10 recycles, indicating that the Fe-Ce@γ-Al2O3 catalyst had good catalytic stability and reusability. In summary, the Fe-Ce@γ-Al2O3 catalysts demonstrate sustained practical effectiveness and high catalytic efficiency, making them suitable for the treatment of ROC.