Photocatalytic degradation of disperse dye Violet-26 using TiO2 and ZnO nanomaterials and process variable optimization

Abstract

The degradation of disperse V-26 in solution using UV; UV/H2O2, UV/H2O2/TiO2 and UV/H2O2/ZnO were investigated. The impacts of various key parameters i.e. initial pH, concentration of hydrogen peroxide (H2O2) dose and the dye concentration effect on degradation were studied. The maximum degradation of 93 % was optimized using UV/H2O2/TiO2 at pH 3 in 60 min. Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GCMS) were applied to check the products obtained after complete degradation. The removal of peaks of certain groups present in dye molecule assured the maximum degradation of dispersive V-26. In biological treatment, cytotoxicity reduction and Ames test were used to check the toxicity level of products. Certain water parameters i.e. dissolved oxygen (DO), chemical oxygen demand (COD) and biological oxygen demand (BOD) were also performed to ensure the maximum degradation of DV-26. DO was increased up to 82 %. The COD and BOD were reduced considerably owing to the treatment of disperse dye Violet 26 at optimum settings of process variables. The degradation of disperse dye V-26 with UV/H2O2/ZnO was 90.1 % which increased up to 93 % with the alternative photo-catalyst UV/H2O2/TiO2. Keywords: Disperse V-26, UV, H2O2, TiO2, ZnO, FTIR, GC–MS, Toxicity