The Journal of

Background: Dyes have complicated structure, are usually toxic and resistant to biological treatment which entere into environment by industrial waste streams. The aim of this study was the removal of reactive red 198 dye (RR 198) by photolysis (UV) and photocatalytical (TiO2/UVC) processes. This study was conducted to investigate the effects of dye concentration, pH, TiO₂ dose, and contact time.

Methods: The study was carried out by drawing on batch reactor. Synthetic wastewater was prepared by solving of RR198 in tap water.Dye concentration was determined with spectrophotometer on 518 nm.

Results: The results of this study show that Tio₂/UV process is more effective than UV-C process alone. The results of the study also show that constant rate of photochemical degradation in acidic pH and during photocatalytic degradation process was 0.0019 and o.0381 min^_1, respectively. Photolysis and photocatalytic degradation of considered dye follow the first order kinetic model. Increasing 0f Tio₂ dose from 0.4 to 10 gr led to Increasing of dye removal efficiency from 97.8 to 100%. Increasing of dye concentration from 100 to 250 mg/l and pH from 4 to 10 led to decreasing of dye degradation efficiency from 100 to 97.66 and from 100 to 94.6, respectively. The best efficiency was at pH=4.

Conclusion: Removal of RR 198 with photolysis and photocatalitical processes has the best efficiency in acidic condition (pH=4) among which the TiO2/UVC process is better than the UVC.