Effect of oxidants on photoelectrocatalytic decolourization using α-Fe2O3/TiO2/activated charcoal plate nanocomposite under visible light

Abstract

The present study is to investigate the effect of oxidants H₂O₂, S₂O₈²⁻, BrO₃⁻, ClO₃⁻ and IO₄⁻ with different concentrations on photoelectrocatalytic decolourization of Lanasol yellow 4G (LY4G) as a model contaminant using α-Fe₂O₃/TiO₂/activated charcoal plate (ACP) nanocomposite under visible light. In this system, the decolourization efficiency increased with increasing BrO₃⁻, ClO₃⁻ and IO₄⁻ doses but reached an optimum amount with H₂O₂ and S₂O₈²⁻ at 1 mM. Experimental data revealed that the decolourization rate of LY4G in all of the processes obeyed pseudo-first-order kinetics. Total organic carbon (TOC) results indicated that 21% and 100% of organic substrate were mineralized respectively after 80 min and 8 h. The gas chromatography-mass spectrometry (GC-MS) analysis was employed to identify the intermediate products. Also, a plausible degradation pathway was proposed. Finally, the real wastewater treatment was investigated by chemical oxygen demand (COD) measurements.