Photocatalytic removal of organophosphorus pesticide by the WO3-Fe3O4/rGO photocatalyst under visible light

Abstract

The WO₃-Fe₃O₄/reduced graphene oxide (rGO) composite was synthesized with a hydrothermal method for the photocatalytic removal of diazinon (DZ) in visible light. The influence of catalyst concentration (0.5-1.5 g L^-1), pH (5-9), and initial pollutant value (5-15 mg L^-1) on the pesticide degradation was studied. The performance of the WO₃-Fe₃O₄/rGO nanocomposite for DZ degradation under visible light shows 94% degradation of 5 mg L^-1 DZ for 100 min with 1 g L^-1 nanocomposite, and the degradation kinetic was modeled in pseudo-first order (PFO) and the maximum k_obs was 0.0248 min^-1. The photocatalytic mechanism and the intermediates of DZ degradation were identified. In addition, the WO₃-Fe₃O₄/rGO catalyst showed reusability after 4 runs. The results of this work illustrate that the WO₃-Fe₃O₄/rGO nanocomposite can be applied for real use owing to its high catalytic performance.

Keywords: Diazinon; Mechanism; Photocatalytic degradation; WO3-Fe3O4/rGO.