Effective removal of Eriochrome black T by a novel ZnxCu01-xFe2O4/C3N4 composite under simulated visible light irradiation

Abstract A new ZnxCu1−x Fe₂O₄/C₃N₄ composite was successfully prepared through a precipitation-assisted calcining technology. The characterization of the as-synthesized catalysts was performed using various analytical techniques. When compared with pure g-C₃N₄, pristine ZnFe₂O₄ and bare CuFe₂O₄, the ZnxCu1−xFe₂O₄/g-C₃N₄ composite exhibits higher photo-catalytic degradation of Eriochrome black T (EBT) under a visible light irradiation. When the molar ratio of Zn/Cu (1/1) and the mass ratio of ZnxCu01−xFe₂O₄ (50%) in the hybrid nanocomposite, ZnxCu1−xFe₂O₄/g-C₃N₄ composite exhibits high EBT removal efficiency of 99.73% by adding sodium persulfate (SPS) in waste water within 120 min of the photocatalytic degradation experiment. Enhanced the visible light absorption ability and the suppression of photoexcited charge carriers is also achieved by forming heterojunctions between Zn0.5Cu0.5Fe₂O₄ and g-C₃N₄. The Zn0.5Cu0.5Fe₂O₄/g-C₃N₄ exhibited 2.91 times higher degradation efficiency than Zn0.5Cu0.5Fe₂O₄ nanoparticles and 1.96 times higher degradation efficiency than g-C₃N₄. The trapping experiments were performed by adding different eliminating agents and it shows that the photodegradation of EBT was mainly caused by electron hole (h⁺), superoxide ion(·O₂⁻) and sulfate radical (·SO₄⁻). Among these resctive species, electron holes (h⁺) are the predominant reactive species. This study provided a promising approach for the treatment of contaminated water using ZnxCu1−xFe₂O₄/g-C₃N₄ as a photocatalyst.