Synergy between copper and cobalt on 3D Co/CuO complex promotes peroxymonosulfate activation

Abstract

Activation of peroxymonosulfate (PMS) to degrade refractory antibiotics is an essential branch of advanced oxidation processes (AOPs). We reported in this study that the (111) and (002) crystal planes of CuO with the (311) crystal plane of Cu0.72Co2.28O4 formed surface heterojunctions, which are used as interfaces for PMS adsorption to explore the performance of different heterojunctions. The formation of Cu0.72Co2.28O4/CuO heterojunction makes up for the CuO (002) surface’s shortcomings and improves the adsorption and activation of PMS by the CuO (002) surface. The heterojunction significantly grows the length of the PMS’ O-O bond compared to the single-crystal surface, which leads to lower energy required for PMS’ O-O bond breaking and further verified the increased covalent character. Based on the quality influencing factors values, the influence of four factors on sulfamethoxazole (SMX) deterioration fits as follows: HCO3– has the largest relative relevance among the factors, followed by H2PO4-, NO3–, and Cl-. The Box-Behnken methodology fitted the optimum efficiency with the initial concentration of Cl-, NO3–, H2PO4-, and HCO3– were 8.0, 10.0, 12.5, and 7.5 mM, respectively. The SMX’s atoms (N, and O) have higher electrophilic attack sites, indicating these atoms are electrophilic attack sites.