Optimization of Photocatalytic Decolorization of the Azo Dye Direct Orange 34 by Statistical Experimental Design

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.

PREPARATION AND CHARACTERIZATION OF ZnO/CuO SEMICONDUCTOR AND PHOTOCATALYTIC ACTIVITY ON THE DECOLORIZATION OF DIRECT RED 80 AZODYE

“…For example, the massive discharge of effluents from the textile industry, especially in the dyeing process, about 20 % of dyes and large amounts of water are discarded into the streams and rivers [1][2][3][4] . Most of the dyes belong to the low cost azo class, with one or more azo (-N=N-) groups bonded to the aromatic groups, which give large stability and then are not susceptible to the treatment by conventional techniques as precipitation, thermal processes, reverse osmosis, and biological treatment 5 .…”

In vitro Photo‐Oxidation of Pyruvate to Acetyl: A Main Source for the Formation of Acetyl Coenzyme A in the Citric Acid Cycle to Perform Biochemical Reactions

“…15 Semiconductors (e.g., TiO 2 , ZnO, Fe 2 O 3 , CdS, and ZnS) can act as sensitizers for light-reduced redox processes due to their electronic structure, which is characterized by a filled valence band and an empty conduction band. 16,17 The solution-phase photochemistry of several a-keto esters has been studied by several investigators. [18][19][20] In alcoholic solvents at room temperature, both ethyl pyruvate and ethyl benzoylformate are efficiently photoreduced to the corresponding pinacols.…”