Photodegradation and Adsorption of Methyl Orange and Methylene Blue Dyes on TiO2

Dyes are extensively used in the textile industry and a considerable amount of water is consumed during dyeing and finishing operations. These wastewaters are discharged in rivers or public sewerage treatment plants and are highly coloured and contaminated. This creates a major environmental problem primarily due to substantial amounts of unfixed dyes released in wastewater. These dyes are characterized by low biodegrability which makes them a source of pollution. In this research work, using two model dyes (Methyl Orange and Methylene Blue) the possibility of degrading the dye wastewaters is investigated with the objective of their effective removal from wastewaters. Photocatalytic degradation was used for dye removal. TiO2 was used as a photocatalyst. As a source of UV light, UV tubes were used and a UV/Vis spectrophotometer was used to monitor the changes in dye concentrations. From the changes in concentration during irradiation, the rate of degradation was determined. After irradiation, the amount of Methyl Orange adsorbed on the surface of TiO2 catalyst was determined for the various concentrations. The results showed that TiO2 photocatalyst shows a high activity for (Methyl Orange /Methylene Blue) degradation under UV irradiation. Amount of adsorbed Methyl Orange increases with dye concentration and for concentrations higher than 1 10-4 M it increases only slightly. It means that there is a direct relation between amount adsorbed and degradation rate and thus Photodegradation of dyes using TiO2 can be used for treatment of colored industrial effluents containing dyes. In place where we have plenty of sunlight solar radiation can be used for degradation.