A study on semiconductor oxides mediated photocatalytic degradation of textile dyes in aqueous solutions and effluent

Abstract

The issue of wastewater treatment and disposal from industries is becoming more and more complex now-a-days due to the increasing amount and variety of wastewater. The textile industry derives much concern in this regard, as it produces large quantities of highly coloured effluents that are toxic and resistant to destruction by biological treatment methods. The studies on the degradation of the anthraquinone dye Vat Yellow 4 in the presence of TiO2 show that the degradation under solar irradiation takes place to lesser extent compared to the degradation under UV irradiation. Optimization of process parameters and the study of the effect of oxidants and inorganic substances were also carried out for this dye under both UV and solar irradiation. Prior to the studies on the degradation of effluent taken from a textile industry located in an industrial area in Erode city, it was decided to just assess the overall impact of the effluents from industries on the quality of ground water in the area. Wide variation was observed between the quality of water taken from locations close to the textile industries and the locations away from those industries. This shows that the effluents discharged from the textile industries have considerable impact on the quality of water in these areas. Finally, effluent was collected from the flow equalisation tank of an industry. Its characteristics were studied and then the effluent was subjected to UV irradiation in the presence of TiO2 for optimising the process parameters for maximum degradation of the effluent and at the same time to ensure near neutral pH of the treated effluent as it will increase the ease of the effluent to undergo subsequent biological treatment. Among the various methods used for the photocatalytic degradation of the effluent, the treatment under UV irradiation in the presence of activated carbon loaded TiO2 results in maximum degradation of the effluent under identical conditions. newline