Abstract

Owing to high volume of dye in their wastewater, textile industries are one of the main industries which pollute the environment. Reactive dyes which are widely used in textile industries have complex structure, are mainly toxic and cannot be purified using classical methods of wastewater treatment. The aim of this research was to study the effects of operating parameters on photocatalytic degradation of reactive red 198 (RR198) using TiO2/UV-C photocatalytic process. This study was carried out in laboratory scale and in batch system. The synthetic wastewater was prepared from dissolution of reactive red 198 dye in city drinking water and the effect of initial dye concentration, TiO2 dose, pH solution and contact time were examined. The dye concentration was determined using spectrophotometer in wavelength of 518 nanometers. The results revealed that as TiO2 dose increases from 0.4-1.0 g/L, the dye removal efficiency increases from 97-100 . However, as initial dye concentration increases from 100-250 mg/L and as pH increases from 4-10, the removal efficiency decreases from 100-97 and from 100-94, respectively. The best dye removal efficiency was achieved in pH solution: 4. The highest removal efficiency of reactive red 198 dye is best achieved through photochemical and photocatalytic processes in acidic conditions; among them, photocatalytic processes are the most effective ones. The kinetic study showed that the reactive red 198 by TiO2/UV-C photocatalytic was followed to first order kinetic as well as other kinetic models.