Enhanced photocatalytic degradation of acephate pesticide over MCM-41/Co3O4 nanocomposite synthesized from rice husk silica gel and Peach leaves

Abstract

Novel green nanocomposite from mesoporous MCM-41 and Co3O4 was synthesized from rice husk based silica gel and using the green extract of Peach leaves as reducing reagent. The composite was labeled as RH-MCM-41/Co3O4 and characterized by different techniques as green photocatalyst in the degradation of Acephate pesticide under visible light illumination. The composite showed well developed spherical MCM-41 particles decorated by nano Co3O4 nanoparticles with stunning surface area and low bandgap energy (1.51 eV). The composite displayed superior photocatalytic activities in the oxidation of Acephate which reflected in a complete degradation of different concentrations of it after 40 min (50 mg/L), 60 min (100 mg/L), 100 min (150 mg/L) and 140 min (200 mg/L) using 0.25 g of the composite. The complete removal of the present TOC for treatment of 100 mg/L acephate was achieved using 0.25 g after 70 min reflecting the formation of intermediate compounds during the oxidation steps. The reported intermediate compounds are CH3C(O)NH2, CH3O(CH3S)P(O)NH2, (CH3O)2P(O)SCH3, CH3OP(O)(OH)2, CH3SS(O)2CH3, and (COOH)2. All the formed intermediate compounds were degraded under the visible light photocatalytic activity of RH-MCM-41/Co3O4 into NO3−, SO42-, PO43-, and CO2 as final products.