Effective oxidation of methyl parathion pesticide in water over recycled glass based-MCM-41 decorated by green Co3O4 nanoparticles

Abstract

Pieces of glass as solid wastes were recycled in the synthesis of highly order MCM-41 that decorated by green fabricated Co3O4 nanoparticles using the green extract of green tea leaves forming novel green nano-composite. The synthetic Co3O4/MCM-41 exhibit high surface area, low bandgap energy (1.63 eV), and typical spherical morphology decorated by Co3O4 nanoparticles. The composite was evaluated as green photocatalyst in effective oxidation of methyl parathion pesticide in the presence of a visible light source. The degradation results revealed complete removal of 50 mg/L and 100 mg/L after 60 min and 90 min, respectively using 0.25 of the catalyst at pH 8. The detection of the TOC in the treated methyl parathion solution gives strong indications about the formation of organic intermediate compounds during the oxidation steps. The main detected intermediate compound are C6H5OH(NO2), C6H5OH, (CH3O)3P(S), C6H4(OH)2, C6H3(OH)3, C6H4(NH2)OP(O)(OCH3)2, (CH3O)2P(O)OH, (CH2)2C(OH)OH(CHO)OC(O), and HO2C(CH2)2C(O)CHO. The detected intermediate compounds converted into SO42−, PO43−, NO3−, and CO2 under the extensive photocatalytic of them over Co3O4/MCM-41. The oxidizing species trapping test verified the controlling of the methyl parathion degradation pathway by the hydroxyl radicals. Finally, the composite showed significant reusability properties and applied five times in the oxidation of methyl parathion with considerable degradation percentages.