Photocatalytic dissipation of kresoxim methyl from soil using zinc oxide nanoparticles: synthesis, characterization, and kinetic studies.

Kresoxim methyl fungicide is commonly used to prevent fungal diseases in fruits, vegetables, and other plants. However, its toxicity and persistence in soil and water raise significant environmental concerns. Reducing its concentration in soil is essential to limit its movement to surface and ground water systems. In this context, semiconductor metal nanoparticles; specifically, ZnO nanoparticles, have emerged as promising agents for rapid degradation of organic pollutants, including pesticides. However, their photocatalytic performance in soil systems remains underexplored compared with that in aqueous environment due to the natural complexity and heterogeneity of soil matrices. The present study investigates the photocatalytic dissipation of Kresoxim methyl in two different soils with ZnO nanoparticles as a catalyst. The synthesized nanoparticles were characterized using SEM-EDX, XRD, BET, etc., revealing the formation of pure hexagonal wurtzite phase ZnO nanoparticles (15.75 nm) with a BET surface area of 29.8 m2/g and a band gap of 3.228 eV. The dissipation was examined at three ZnO nanoparticle doses, with optimum performance observed at 0.3%. Dissipation followed second order kinetics with half-lives of 19.8 hr (SH1) and 17.1 hr (IG3). LC-MS analysis identified five transformation products, including three novel compounds, providing insights into the degradation pathway for Kresoxim methyl.