MOF-derived CoFe2O4/Fe2O3 embedded in g-C3N4 as high-efficient Z-scheme photocatalysts for enhanced degradation of emerging organic pollutants in the presence of persulfate

Photocatalysis is a promising strategy to remove contaminants from wastewater. Herein, a novel g-C3N4@CoFe2O4/Fe2O3 composite was synthesized via a feasible hydrothermal and calcination method. Benefiting from the Z-scheme heterojunction formed between MOF-derived CoFe2O4/Fe2O3 and g-C3N4, the recombination of photoinduced electrons and holes could be inhibited effectively. Meanwhile, doping a little amount of MOF-derived CoFe2O4/Fe2O3 could remarkably enhance visible light absorption ability of g-C3N4 and reduce band gap of g-C3N4. Then, the resulting hybrid photocatalysts were employed as a high-efficient mediator to activate persulfate for degrading emergent organic contaminants under visible light irradiation. Significantly, TC of 99.7%, BPA of 98.1%, SMX of 94.8%, DFC of 97.0%, IBP of 96.1% and OFX of 96.5% could be removed within 80 min. Some important factors influencing photocatalytic degradation process were also investigated. The trapping experiments and EPR tests revealed that both SO4− and OH were involved in photocatalytic reaction. Besides, the introduction of MOF-derived CoFe2O4/Fe2O3 provided a new approach for generating radical species. More importantly, obtained g-C3N4@CoFe2O4/Fe2O3-2 composites with good stability exhibited great application potential in the actual degradation tests. To sum up, current work provided novel ideas for photocatalytic oxidation technology in the organic pollution degradation.