Enhanced methyl orange removal in aqueous solutions using bio-catalytic metal oxides derived from pomegranate peel waste: a green chemistry evaluation

This study investigates the potential of pomegranate peel (PP) as a raw material for synthesizing a novel biocatalyst metal oxide (BCMO) aimed at the efficient removal of methyl orange (MO) dye from aqueous solutions. The adsorption capacities of both PP and BCMO were systematically evaluated. PP was subjected to inorganic salt treatment and calcination to enhance its adsorption capacity and increase attractive forces at the nanoparticle level. The surface characteristics of the biocatalyst were thoroughly examined using FTIR, SEM, BET analysis, and EDX spectroscopy, revealing the development of a crystalline structure following treatment with Mg(NO₃)₂⋅6H₂O, along with observable changes in surface morphology and elemental composition. Under standard conditions, BCMO demonstrated a significant increase in efficiency, achieving 99.80% removal for 100 mg/L of methyl orange, compared to 44% for untreated PP at 50 mg/L. Kinetic analysis indicated a transition from pseudo-first-order to pseudo-second-order, signifying a shift from physical to chemical adsorption. This transition resulted in a substantial reduction in equilibrium time and a significant increase in maximum adsorption capacity from 17.3637 to 176.686 mg/g. Furthermore, the catalytic efficiency of BCMO was assessed over seven cycles, showing only a minor 5% reduction in efficiency, indicating its potential for practical applications. The environmental sustainability of the road was assessed using the AGREE and BAGI indicators, both of which are considered exemplary measures of environmental friendliness.

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