Dual‐functional UiO‐66/g‐C3N4 composites for photocatalytic pesticide removal and in situ adsorption of phosphate byproducts in water

Abstract

AbstractBACKGROUNDWith the increasing global demand for food, a significant amount of organophosphorus pesticides is applied to farmland, leading to pollution as they are discharged into natural water bodies with agricultural runoff. This study employed a coupling approach, utilizing a 6:4 mass ratio of zirconium‐based metal–organic framework UiO‐66 and g‐C3N4 through a grinding and annealing method to construct a Z‐type heterojunction composite material named UG 6:4.RESULTSThis material is employed for photocatalytic removal of the representative organophosphorus pesticide, dichlorvos (DDVP), from water and simultaneous in situ adsorption of its inorganic phosphorus byproducts. Results demonstrate that for initial DDVP concentrations below 5 mg L−1 (calculated as total phosphorus), both the mineralization rate under ultraviolet light irradiation with a wavelength of 365 nm and a power of 125 W and the adsorption rate of phosphorus were 100% when the pH was 6 and the UG 6:4 dosage was 0.2 g L−1. The sheet‐like g‐C3N4 tightly envelops the surface of UiO‐66, forming a Z‐scheme heterojunction. This structure imparts UG 6:4 with enhanced light absorption, faster generation and separation of photogenerated electron–hole pairs compared to individual UiO‐66 or g‐C3N4, and the establishment of an internal electric field suppresses the recombination of photogenerated charge carriers.CONCLUSIONConsequently, UG 6:4 exhibits outstanding photocatalytic pesticide removal capabilities. Furthermore, UG 6:4 demonstrates specific adsorption of inorganic phosphorus through electrostatic attraction and ligand exchange. This study indicates that UG 6:4 is a promising dual‐functional photocatalytic adsorbent with excellent application prospects. © 2024 Society of Chemical Industry (SCI).