Decolorization of azo dyes by photo electro adsorption process using polyaniline coated electrode

Abstract

This study is a report on the photo electro adsorption (PEA) decolorization of a mixture of three azo dyes, i.e., Acid Red 88 (AR88), Acid Blue 92 (AB92), and Acid Orange 2 (AO2) with polyaniline-modified electrode as a conductive polymer. Aniline was electropolymerized on steel electrode by being immersed in a solution containing HClO4 as the supporting electrolyte and NaClO4 as the dopant. This modified electrode was then used in a non-continuous reactor using UV irradiation for the decolorization of azo dyes. To obtain the best conditions for high decolorization efficiency, experiments were carried out at different operational conditions, including initial dye concentration, pH, and bias potential. The morphology of polyaniline film was analyzed by scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) spectrum was obtained to characterize polyaniline and dyes. Energy consumption was calculated to be 3.6kWh/m3 after 36min of treatment process. Maximum removal of 96% was achieved for the mixture of AR88, AB92, and AO2 in aqueous solution at pH 5, initial dye concentration of 30mgL−1, and bias potential of 1.3V after 40min of PEA process. The results indicate that the PEA process could be effectively applied to the removal of industrial effluents.