Characteristics of CuO-MoO3-P2O5 catalyst and its catalytic wet oxidation (CWO) of dye wastewater under extremely mild conditions

In order to develop a catalyst with high activity for catalytic wet oxidation (CWO) processing at lower temperatures (35 degrees C) and atmospheric pressure, a new CuOMoO3-P2O5 catalyst was synthesized by a solid-state reaction method and was characterized by X-ray diffraction (XRD), Fourier transformation infrared spectrometer (FTIR), X-ray photoelectron spectroscopy (XPS), selected area electronic diffraction (SAED), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDXS) for elemental mapping. Methylene blue (MB) was adopted to investigate the catalytic activity of CuO-MoO3-P2O5 in CWO processing. The results show that this new catalyst has a high catalytic activity to decolorize MB under mild condition. The color removal of MB (the initial concentration was 0.3 g L-1 and initial pH was 5) can reach to 99.26% within 10 min at 35 degrees C and atmospheric pressure. Catalyst life-span and selectivity were also tested, and the results show that after the catalyst was used three times, catalyst activity still remains. Selectivity testing shows that CuOMoo(3)-P2O5 has high catalytic activity on degradation of MB, whereas this catalyst has less impact on methyl orange (the color removal was 99.65% for MB and 55% for methyl orange under the same conditions). According to the experimental results, a possible mechanism of catalytic degradation of MB was proposed.