Removal of Direct Red Dye 23 from Water and Wastewater Using S2O8 -2 Oxidant Activated by UV Irradiation:An Investigation on the Operational Parameters

The photo-oxidative decolorization of direct red 23 (dr23), a textile dye which is suspected to be carcinogenic was investigated using peroxydisulfate activated by uv irradiation and heat in a batch photo-reactor at experimental conditions. a very simple analytical method, direct uv–vis spectrophotometric detection, was utilized for the progress of photo-oxidative decolorization of dye in aqueous medium. the effect of operational parameters namely initial peroxydisulfate concentration, ph and temperature of reaction, additional photo-catalyst on the decolorization rate was truly investigated. the results showed that use of uv/s2o8 2- system was a highly effective way to remove colored components from contaminated waters. optimum conditions for maximum degradation was acidic ph (ph=2), temperature of 50°c with 7.5 mm of peroxydisulfate. also, it was observed that dye degradation was enhanced using nano-tio2 glass beads as photo-catalyst and peroxydisulfate consumption was significantly reduced to achieve the same percentages of dye degradation which was observed in uv/s2o8 2- system at the same conditions.