Photochemical and Photocatalytic Detoxification of Reactive Dyebath Wastewater by the Fenton’s Reagent and Novel TiO2 Powders

Abstract

The study described herein aimed to investigate the homogeneous(Fenton/UV-C) and heterogeneous (TiO2/UV-A) advanced oxidation ofcommonly used reactive dyestuffs in simulated dyebath effluents. For thePhoto Fenton (Fe2+/H2O2/UV-C) reaction the effect of the initial H2O2dose on the oxidative reaction rates was examined. Further, thephotocatalytic treatment efficiency of two novel anatase TiO2 powders(Millennium PC 500 and Sachtleben Mikroanatas) and platinized DegussaP25 TiO2 type were compared with that of the more conventional P25 atdifferent reaction pH's. In the case of the Photo Fenton reactions, thetreatment performance was strongly affected by the initial H2O2concentration, whereas for the TiO2/UV-A process only the PC 500 TiO2powder exhibited a significantly pH dependent reaction efficiency. Thedecolourization rates followed the decreasing order of Fenton/UV-C >Pt-P25/UV-A > Mikroanatas/UV-A > P25/UV-A > PC 500/UV-A, whereas thedecreasing order for TOC removal efficiency was Fenton/UV-C >Mikroanatas/UV-A > Pt-P25/UV-A > P25/UV-A > PC 500/UV-A for the selectedreaction conditions. Removal of optical density at 254 nm wavelengthranged between 75 % (Mikroanatas/UV-A) and 96 % (P25/UV-A).