Heterogeneous photo-Fenton oxidation of methylene blue using CdS-carbon nanotube/TiO2 under visible light

Heterogeneous photo-Fenton oxidation using CdS/multi-walled carbon nanotube-TiO2 (CdS/MWCNT-TiO2) under visible light relied on combination of the photocatalytic, photo-Fenton and photosensitizing oxidation. The photo-Fenton reactions resulted in much faster and higher removal of methylene blue and total organic carbon than the dark Fenton oxidation and the photocatalytic degradation alone at the selected conditions. The optimum molar ratio of [methylene blue]:[H2O2]: [Fe3+] (1:12:3.4) in the photo-Fenton oxidation indicated cost-effectiveness of the process. The scavenging tests of the hydroxyl radicals and the valence holes suggested that the hydroxyl radical-driven oxidation was the major step among the multiple reactions in the photo-Fenton oxidation. (C) 2014 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.