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

摘要

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 alpha-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.