Catalytic role of surfactants on the decolorization of mixed Azo dyes effluents (MDE) through Fenton advanced oxidation process (AOP)

The kinetic studies of the decolorization of mixed azo dyes containing dyeing effluent (MDE) was been studied in both aqueous and aqueous-surfactant systems. The study result showed that the addition of surfactants (cationic-Cetyltrimethylammonium Bromide (CTAB), anionic-Sodium Dodecyl Sulfate (SDS), and nonionic-Alkylphenyl Polyethylene Glycol (TX-100)) enhance the azo dyes decolorization rates from MDE, demonstrate that surfactants function as catalyst for the dyes degradation through Fenton Advanced Oxidation Process (AOP). Surfactant increase the rate of azo dyes decolorization by facilitating the binding of the dyes molecules with reactive oxidation free radicals(•OH), thus concentrating the reactive species by strong electrostatic interaction for active collisions. Moreover, the decolorization rate of azo dyes has been recognized to be depended on the concentration of Fenton reagents, surfactants, and on reaction temperature. The surfactants catalytic efficiency on the azo dyes decolorization rate from MDE, followed the sequence: Aqueous (62.26%) < [CTAB] (65.63%) < [SDS] (70.22%) < [TX-100] (75.74%) under constant reaction conditions. Up to the date, dyes decolorization from textiles effluents by Fenton AOP in impractical, because the process uses high reactant concentrations (Fe2+, H2O2), high acidic pH (3–4) along high temperature (50–80 °C). While, our study the surfactant catalytic Fenton AOP for dyes removal over decolorization from dyeing effluents, limits the reagents concentration at low temperature (30 °C), would be applicable for real effluent treatment. The finding of the study is the opening of new route for organic pollutants removal through Fenton AOP from textiles wastewater.