Fabrication of Fe-CoTiO3/TiO2/Ti catalytic membrane for peroxymonosulfate activation to efficient sulfamethoxazole degradation

In heterogeneous catalysis of the sulfate radical (SO4∙-)-based advanced oxidation processes, the limited availability of exposed active sites and the inert membrane substrate that does not participate in redox reactions pose challenges to the pollutant degradation efficiencies. This study fabricated a Fe-doped CoTiO3/TiO2/Ti (FCTT) catalytic membrane to initiate peroxymonosulfate (PMS) activation in a continuous flow-through reactor for the degradation of sulfamethoxazole (SMX). Fe doped into the lattice of CoTiO3 significantly improved the conversion efficiency between Co2+ and Co3+, promoting the degradation rate of SMX by 12.17 %. Additionally, we employed TiO2 nanotubes featured with highly accessible porous structures and a large surface area (7.78 m2/g) as a substrate in the system. The formation of Co-O-Ti bond signally reduced the Co ion leaching (43 μg/L after 10 h of use) while ensuring the reusability (>90.42 % in 24 h) of FCTT. The species of SO4∙-, •OH, O2∙- and 1O2 were involved in FCTT/PMS system, jointly participated the degradation of SMX in the FCTT/PMS system. Theoretical calculations revealed the nitrogen on amino groups was the most susceptible site to be attacked. This research provides valuable insights and approaches for developing highly efficient catalysts in heterogeneous catalytic oxidation.