Hydrothermal deposition of CoFe2O4 nanoparticles on activated carbon fibers promotes atrazine removal via physical adsorption and photo-Fenton degradation

Magnetic CoFe2O4 serves as a promising photo-Fenton reagent, but its low adsorption ability and catalytic activity inhibit the effective removal of atrazine (ATZ). Herein, activated carbon fiber/cobalt ferrite (ACF/CoFe2O4) composites were fabricated by hydrothermal deposition of CoFe2O4 nanoparticles around ACFs. As compared with CoFe2O4 nanoparticles, the ACF/CoFe2O4 composites showed better adsorption ability due to the synergistic effect between CoFe2O4 nanoparticles and ACF felts. The ATZ adsorption trend over the ACF/CoFe2O4 composites matched well with pseudo-first-order and pseudo-second-order kinetics model, suggesting that the diffusion and adsorption reaction played equal contribution to the ATZ adsorption. Notably, the ACFs in the ACF/CoFe2O4 composites decreased the band gap of CoFe2O4 nanoparticles from 1.82 eV to 1.62 eV, facilitating the enhanced photocatalytic activity. In the reaction system of ATZ, H2O2 and ACF/CoFe2O4 composites, the remarkable changes of Co and Fe valence states demonstrated that both Co3+/Co2+ and Fe3+/Fe2+ circulations took part in the Fenton-like reaction. The hydroxyl radicals that were generated in the photo-Fenton system effectively induced the oxidative degradation of ATZ. Moreover, the photo-Fenton degradation pathway of ATZ was proposed according to LC-MS analyses. Hence, the ACF/CoFe2O4 composite was a promising photo-Fenton catalyst to remove pesticide pollutants via physical adsorption and photo-Fenton degradation.