Highly efficient and robust CuO1-x/SiO2 catalyst for peroxymonosulfate activation for removal of tetracycline

Advanced oxidation process is powerful for removal of tetracycline (TC) from wastewater by the catalytic peroxymonosulfate (PMS) activation. It is a key to full dispersion and confinement of active centers in the catalytic system. Herein, the active Cu species were supported into mesoporous SiO 2 , which was used to activate PMS for removal of TC. Reduction temperatures revealed that the vast majority of CuO can be reduced to Cu 2 O and Cu species at 300 °C under H 2 /Ar, which offered the best performance for TC removal efficiency of 97.1 %. Noteworthily, CuO 1-x /SiO 2 -300 displayed a better activity than CuO 1-x -300, indicating that the mesoporous SiO 2 enhanced the dispersion of active Cu species. Meanwhile, the leaching Cu concentration was lower in CuO 1-x /SiO 2 -300 than CuO 1-x -300, which was also lower than that stated by WHO standard for drinking water , avoiding the secondary pollution. Due to confinement effect of mesoporous SiO 2 , CuO 1-x /SiO 2 -300 presented an excellent stability in cyclic experiments. ESR measurements revealed that rich active species such as ·OH, SO 4 ·- , O 2 ·- and 1 O 2 were generated in CuO 1-x /SiO 2 -300/PMS system. Quenching experiments revealed that these active species played an important role during the TC degradation, in which non-radical ( 1 O 2 ) pathway dominated, and the radical (·OH, SO 4 ·- and O 2 ·- ) pathway also presented innegligible influence simultaneously. This work blazed a new trail to activate PMS for removing TC from wastewater. • The CuO 1-x /SiO 2 -300/PMS system was presented for removal of tetracycline from wastewater. • The Cu active species were fully dispersed and confined in mesoporous SiO 2 . • The valence state of Cu is a key to PMS activation. • The CuO 1-x /SiO 2 -300 offered an excellent activity and stability. • Under the optimal condition, TC removal efficiency achieved 97.1 % over CuO 1-x /SiO 2 -300/PMS system.