Preparation of Co-MnOx/GAC catalyst by high-gravity technology and its mechanism for synergistic catalytic ozone degradation of phenol

Abstract

The impregnation method for preparing catalysts often faces challenges such as prolonged preparation times and poor dispersion of active components due to the limited mobility of the impregnation liquid. The rotating packed bed (RPB) can break the precursor solution into fine droplets, enabling dynamic impregnation of active components onto the surface of activated carbon. This approach facilitates the uniform distribution of active components on the carrier and enhances the stability and performance of the catalyst. In this study, activated carbon catalysts were prepared using high-gravity technology. It was found that the preparation time for Co-MnO_x/GAC using the RPB method was reduced by 98%, the catalytic activity increased by 6.62%, and the loadings of active components increased by 13% and 17%, the catalytic activity remained stable after five cycles, with a significantly lower rate of metal dissolution. A suite of complementary analytical techniques demonstrates that Co-MnO_x/GAC(RPB) has higher homogeneity and dispersion. X-ray photoelectron spectroscopy (XPS) results indicate that Co(II) and Mn(IV)/Mn(III) are the primary active sites during the catalytic decomposition of ozone, elucidating the mechanism of synergistic catalytic ozonation by dual-active components. Finally, electron paramagnetic resonance (EPR) confirmed that hydroxyl radicals (·OH) were the predominant reactive species in the reaction.