Improved degradation of methyl orange dye using bio-co-catalyst Se nanoparticles impregnated ZnS photocatalyst under UV irradiation

Abstract

The present work outlines the importance of biosynthesized selenium nanoparticles (SeNPs) as co-catalyst for the enhanced photocatalytic activity of as-prepared ZnS photocatalyst for degradation of methyl orange (MO) dye under UV light irradiation. SeNPs of different wt% were impregnated onto ZnS by calcination at 200°C to make Se-ZnS nanocomposites (Se-ZnSNCs) and characterized by UV–Vis spectroscopy, DLS, XRD, SEM-EDX, TEM and BET surface area analysis. The specific surface area notably increased from 54m2g−1 (ZnS) to 75m2g−1 with different wt% of Se loading. The band edge absorption at 330nm (3.77eV) of bare ZnS significantly red-shifted to 357nm (3.30eV), after 1wt% Se loading (3.30eV). 1wt% Se-ZnSNCs exhibited the highest degradation efficiency (95%) of MO as compared to bare ZnS (55%) under 160min UV light irradiation. The reaction followed pseudo first-order kinetics with an apparent rate constant k=8.42×10−3min−1 where CO2 evolution gradually increased depending on the extent of MO degradation by Se-ZnSNCs under different time period of UV light irradiation.