Ceramic membrane supported with CuO for catalytic degradation of azo dyes using sulfate radicals.

Catalytic membranes containing metal nano-catalyst are widely used in dye wastewater treatment. Comparing to the traditional catalyst loading methods, such as the co-precipitation, the surface grafting, and impregnation et al., hydrothermal method is simple, and the crystals obtained have a uniform distribution and high purity. In this study, CuO nano-catalysts is immobilized on ceramic substrate by hydrothermal method. The prepared membrane is used to activate persulfate (PMS) for the degradation of azo dyes. FTIR, XPS, XRD, and FESEM characterizations prove that CuO is successfully loaded onto the Al2O3 substrate, the optimal loading amount is 0.03 g/cm2. Static degradation experiments show that the composite membrane could degrade 85% of the Congo red within 80 min. In the dynamic degradation process, the degradation efficiency is further improved to a maximum of 96.8% within 80 min, and the permeation flux of catalytic membrane is relatively stable during the degradation process. In long-term experiments, the degradation efficiency still remains at ~ 87% after 4 cycles, indicating good stability. Quenching experiment shows that the main oxidizing radicals are sulfate radical. In conclusion, the prepared membrane can activate PMS efficiently, which has a potential applications in dye wastewater treatment. [ABSTRACT FROM AUTHOR]