Photo-assisted degradation of dyes in a binary system using TiO2 under simulated solar radiation

Wastewater generated from textile industry contains various dyes and other organic compounds. The application of TiO2 for degradation of organic pollutants especially dyes has been studied for decades. However, little data were reported in TiO2 photocatalytic performance for the binary or complex system. Here we investigate the photo-assisted degradation of dyes (Rhodamine B and Methyl orange) using TiO2 under simulated solar radiation in a binary system. The effects of catalyst loading were investigated in both single and binary systems. Analysis of kinetics, the possible degradation mechanisms were discussed, and the degradation pathways are proposed based on the UHPLC-MS analysis. The result shows that in the binary system, the degradation kinetics of the component especially the less reactive one is divided into 2 phases (parallel reaction and single reaction) which still follows the pseudo first-order reaction kinetics. On the other hand, the mechanism, and pathway will follow the single system which eventually will end up with total mineralization of organic dyes.