An investigation of Ca-doped MgO nanoparticles for the improved catalytic degradation of thiamethoxam pesticide subjected to visible light irradiation.

The remediation of pesticides from the environment is one of the most important technology nowadays. Herein, magnesium oxide (MgO) nanoparticles and calcium-doped magnesium oxide (Ca-doped MgO) nanoparticles were synthesized by the co-precipitation method and were used for the degradation of thiamethoxam pesticide in aqueous media. Characterization of the MgO and Ca-doped MgO nanoparticles were performed by XRD, SEM, EDX, and FT-IR analysis to verify the synthesis and variations in chemical composition. The band gap energy and crystalline size of MgO and Ca-doped MgO nanoparticles were found to be 4.8 and 4.7 eV and 33 and 34 nm respectively. The degradation of thiamethoxam was accomplished regarding the impact of catalyst dosage, contact time, temperature, pH, and initial pesticide concentration. The pH study indicates that degradation of thiamethoxam depends on pH and maximum degradation (66%) was obtained at pH 5 using MgO nanoparticles. In contrast, maximum degradation (80%) of thiamethoxam was observed at pH 8 employing Ca-doped MgO nanoparticles. The percentage degradation of thiamethoxam was initially increasing but decreased at higher doses of the catalysts. The degradation of the pesticide was observed to be increased with an increase in contact time while high at room temperature but decreased with a temperature rise. The effect of the initial concertation of pesticide indicates that degradation of pesticide increases at low concentrations but declines at higher concentrations. This research study reveals that doping of MgO nanoparticles with calcium enhanced the degradation of thiamethoxam pesticide in aqueous media.