Photocatalytic degradation of the organophosphorus insecticide chlorpyrifos in aqueous suspensions using a novel activated carbon ZrO2-ZnO nanocomposite under UV light

This paper describes the photocatalytic degradation of the organophosphorus insecticide chlorpyrifos in aqueous suspensions using Schima wallichii activated carbon/ZrO2-ZnO (SWAC/ZrO2-ZnO) nanocomposite in UV light. Analytical techniques such as XRD, FT-IR, TEM-SEAD, XPS, PL, and BET analyzer were used to characterize the SWAC/ZrO2-ZnO nanocomposite. The BET surface area of the photocatalyst was found to be 223.387 m(2)g(-1), having a total pore volume of 0.1845 cm(3)g(-1). The photocatalytic degradation of chlorpyrifos followed pseudo-first-order rate kinetics with a half-life period (t(1/2)) of 7.088 mins and K-ap (apparent rate constant) of 0.09778 min(-1). The mechanism of composite formation was explained using DFT investigations, which demonstrated a favorable immobilization of ZrO2-ZnO on SWAC. Chemical descriptors gained from DFT investigations, such as HOMO-LUMO energy, ionization energy, dipole moment, chemical softness, and chemical hardness, supported an understanding of the relative efficiency and reactivity of ZrO2-ZnO and SWAC/ZrO2-ZnO towards chlorpyrifos degradation.