Facile synthesis of novel magnesium oxide nanoparticles for pesticide sorption from water

Abstract

The quantum of pesticides in surface as well as drinking water has become a serious health hazard. In this experiment, magnesium oxide nanoparticles (MgO NPs) were synthesized using leaves of purple-colored rice variety (Crossa) and utilized for simultaneous removal of three pesticides, namely, thiamethoxam, chlorpyriphos, and fenpropathrin from water. The biogenic MgO NPs were characterized using SEM-EDX, FTIR, XRD, DLS, etc. The optimum synthesis parameters (1 M NaOH, 80 °C, and 2 h) resulted in maximum yield of MgO NPs (87.7 mg), minimum hydrodynamic diameter (35.12 nm), poly dispersity index (0.14) and mean zeta potential (-11 mV). Sorption data of the three pesticides fitted well with non-linear Langmuir and Freundlich isotherm models and non-linear pseudo-second-order kinetic model. The maximum adsorption capacity of MgO NPs for the three pesticides was 87.66 µg/mg, as obtained from the Langmuir isotherm model. Under optimum conditions (initial concentration, 40 mg/L; dose, 30 mg/30 mL; and pH, 9), 60.13, 80.53, and 92.49% removal of thiamethoxam, chlorpyriphos, and fenpropathrin was achieved with a 100% desirability, respectively. Thus, the biogenic MgO NPs could be an efficient adsorbent of pesticides and could be recommended for pesticide decontamination in water treatment plants and domestic water purifier systems.

Keywords: Crossa; Central composite design; MgO NPs; Pesticide removal; Response surface methodology.