Mn3O4@CoHCF nanocomposite for charge transfer regulated kinetic degradation of organophosphate pesticides

Abstract

Organophosphate pesticides like Ethion (ET) and Chlorpyrifos (CP) are widely used in agriculture and this has seriously contaminated the environment, especially water bodies. The Mn3O₄@CoHCF nanohybrids were synthesized using an environmentally friendly method using Aloevera plant extract. The optimal conditions for ethion removal were achieved using 30 mg of nanocatalyst at pH 9 with an initial concentration of 2 mg L-1 while for Chlorpyrifos, 25 mg of catalyst at pH 7 of 10 mg L-1 concentration resulted in effective degradation within 160 minutes. ET and CP were almost entirely removed, exhibiting first-order kinetic behaviour and conformity to the Langmuir adsorption isotherm. Owing to its narrow band gap (2.4 eV), high surface area (44.24 m2 g-1), enhanced particle durability (−34.6 mV), prolonged charge carrier lifetime and reduced hole (h⁺)/electron (e⁻) recombination rate, Z-scheme type Mn₃O₄@CoHCF demonstrates superior photocatalytic performance. GC–MS and scavenger analysis revealed that highly reactive entities, including superoxide and hydroxyl radicals were generated facilitating the degradation of these pesticides into less harmful metabolites. The study demonstrated that Mn₃O₄-modified CoHCF exhibited superior degradation efficiency compared to the parent nanoparticles, achieving 96% removal of ET and 94% of CP. The Mn₃O₄@CoHCF nanohybrid presents itself as a potential nanomaterial for the photocatalytic degradation of pesticides and diverse environmental pollutants. Keywords Mn₃O₄@CoHCF, Aloevera, Ethion, Chlorpyrifos, Photocatalytic degradation, Reusability