Peroxymonosulfate enhanced photodegradation of sulfamethoxazole with TiO2@CuCo2O4 catalysts under simulated solar light

Solar-light-assisted photocatalytic activation of peroxymonosulfate (PMS) is an effective advanced oxidation method for degrading pollutants in water. In this study, several TiO2 supported on CuCo2O4 photocatalysts were successfully synthesized through simple hydrothermal and calcination method with different ratios of TiO2. The synthesized materials were tested for photocatalytic degradation of sulfamethoxazole (SMX) enhanced by PMS activation. The TiO2@CuCo2O4 heterostructures showed a significantly higher photocatalytic degradation of SMX comparing with that of pure CuCo2O4. The TiO2@CuCo2O4 heterostructure with 20% of TiO2 (TO-20-CCO) achieved the highest SMX removal, due to the synergistic effect between CuCo2O4 and TiO2. Besides, the reaction mechanisms induced by TiO2@CuCo2O4/PMS system were examined using trapping tests, which showed that sulfate (SO4•−), hydroxyl (HO•) and superoxide (O2•−) radicals were the most involved in the degradation reaction. The photodegradation mechanism seems to be based in the formation of a n-n heterojunction. This work details an efficient strategy for the synthesis of heterostructured photocatalysts using PMS as activator to degrade the antibiotic residues present in wastewater using solar light irradiation.