Adsorption and degradation of methyl parathion (MP), a toxic organophosphorus pesticide, using NaY/Mn0.5Zn0.5Fe2O4 nanocomposite

Abstract

In this research, the applicability of NaY/Mn0.5Zn0.5Fe2O4 as a new synthesized nanocomposite adsorbent for the adsorption and degradation of methyl parathion (MP, O,O-dimethyl O-p-nitrophenyl phosphorothioate), an organophosphorus pesticide, is investigated. IThe prepared samples were characterized via SEM-EDAX, TEM, XRD, FTIR, VSM and N2-BET techniques. The role of several experimental factors such as contact time, adsorbent dose and initial concentration of methyl parathion on the removal efficiency of this pesticide were considered and evaluated via 31P nuclear magnetic resonance (31PNMR) spectroscopy. 31PNMR spectroscopy showed that methyl parathion was desirably removed by the NaY/Mn0.5Zn0.5Fe2O4 nanocomposite with a yield of more than 90% under certain optimized conditions. Factors including contact time (80 min), adsorbent dose (0.5 g), and initial pesticide concentration (15 mg/L) were studied and optimized for the reaction. Reaction kinetic status was surveyed using a first order model. The values of the half-life (T 1/2) and rate constant (k) were 54.6 min and 0.0127 min−1, respectively. The products of the degradation reaction between methyl parathion and NaY/Mn0.5Zn0.5Fe2O4 were dimethyl phosphorothioic acid (DMPA) and p-nitrophenol (PNP), which are significantly less toxic than the primary pesticide.