Photocatalytic Degradation of Pesticides Using ZnFe₂O₄–TiO₂ Heterojunction Nanocomposites

Abstract

The persistence of pesticides in agricultural wastewater presents significant environmental concerns. In this study, ZnFe₂O₄–TiO₂ heterojunction nanocomposites were synthesized via hydrothermal methods and tested for photocatalytic degradation of chlorpyrifos under simulated sunlight. X-ray diffraction confirmed crystalline phases of both ZnFe₂O₄ and TiO₂, while TEM images revealed nanocomposite structures with intimate contact interfaces. UV–Vis spectroscopy indicated reduced band gap energy (2.2 eV) compared to pristine TiO₂ (3.2 eV), enabling efficient visible light utilization. Photocatalytic tests showed that the composite achieved 89% degradation efficiency within 150 minutes, significantly higher than pure TiO₂ (54%). Radical scavenging studies confirmed hydroxyl radicals as the dominant oxidative species. Reusability tests across five cycles confirmed stable activity, with only 6% performance loss. These results highlight the potential of ZnFe₂O₄–TiO₂ nanocomposites as effective catalysts for sustainable water treatment.