Photocatalytic treatment of textile dyehouse effluents with simulated and natural solar light

In the present study, the photocatalytic treatment of two synthetic textile dyehouse effluents was investigated. The first synthetic effluent (SE1) is a Remazol Black B aqueous solution, while the second one (SE2) is an aqueous mixture of sixteen dyes and auxiliary chemicals that are usually employed in the textile industry. Various illumination sources were studied, while emphasis was given on the use of simulated and natural solar light. Results indicated that the use of solar irradiation can constitute an advantageous treatment strategy, due to its energy efficient and environmentally friendly operation, for textile dyehouse effluents. Specifically, it was observed that total decolorization and mineralization of SE1 occurred after about 120 min and 300 min, respectively, in the presence of at least 2 g L TiO2, under natural sunlight. On the other hand, total decolorization of SE2 was achieved only after 300 min of photocatalytic treatment, while COD removal practically remained unchanged, at about 20%, regardless the applied operating parameters, due to the presence of other organic and inorganic substances. Furthermore, it was found that process efficiency was significantly affected by the catalyst loading.