Wet peroxide oxidation of catechol over copper-based catalysts: inorganic ions effect and degradation pathway of organics

In this study, Cu/Al₂O₃ catalysts were prepared by equal volume wet impregnation for catalytic wet peroxide oxidation (CWPO) of catechol. The crystal structure and elemental composition of the catalysts were investigated by characterization tools like XRD and XPS. The CWPO performance of the catalyst was evaluated through catalytic degradation of catechol in aqueous solution. It was found that 5%Cu/Al2O3 (in wt%) catalyst showed an excellent catalytic performance for catechol degradation. The total organic carbon (TOC) removal rates reached 91% under optimized reaction conditions. Moreover, anions and cations both had an inhibition effect on TOC removal rates. Combined with hydroxyl radical quenching experiments and density functional theory (DFT) study, the catalytic degradation mechanism was proposed to illustrate the degradation pathway of catechol. The catalytic test results as well as the proposed mechanism can provide an insight into studying the degradation pathway of organics in CWPO.