E. Niehues, I. S. Scarminio, K. Takashima
2010
Citations
1
Influential Citations
6
Citations
Journal
Journal of The Chilean Chemical Society
Abstract
abstract The photodecolorization of the azo dye Direct Orange 34 (DO34) was investigated in TiO 2 aqueous suspensions with artificial irradiation at 30oC. The experimental conditions were optimized by a 2 5 factorial design, using the decolorization percentage after 240 min irradiation as the response. The five factors considered were DO34 and TiO 2 concentrations, stirring speed, air saturation, and adsorption time. The addition of hydrogen peroxide and sodium periodate as oxidants increased the decolorization rate. Keywords: photocatalytic decolorization, Direct Orange 34, TiO 2 , oxidant, factorial design. e-mail: keiko@uel.br intrOductiOn Dyes are an abundant class of colored organic compounds that represent an increasing environmental hazard. During dye production and textile manufacturing processes a large amount of wastewater containing dyestuffs with intense color and toxicity can be introduced into aquatic systems and cause severe ecological and environmental problems. Azo dyes, which are aromatic compounds with one or more azo (–N=N–) groups, are the most important and largest class of synthetic dyes used in commercial applications, and they are characterized by azo chromophores