Adsorptive eradication of tartrazine from aqueous solutions onto doped polyaniline

Abstract

A potential polymeric adsorbent, doped polyaniline (PANI) has been investigated for the eradication of the hazardous dye tartrazine from textile effluent. During the adsorption process, the influence of the acidic character of the adsorbate, pH, dose of the adsorbent, dye concentration and time of contact between the adsorbent and adsorbate were evaluated. The outcomes attained from batch experiments were applied to the Langmuir and the Freundlich iso­thermal models. Different error analysis techniques, such as mean square error, root mean square error, the Chi-square test (χ2), sum of absolute errors and sum of squared errors, were determined for the doped polyaniline–tartrazine system. The Langmuir isotherm was established as the best-fit isothermal model, with minimum errors and high regression values. About 90–97 % removal was achieved in the first 70 min. A positive enthalpy value implied the adsorption process was endothermic. The energy of activation for the dye adsorbent sys­tem was found to be 28.9 kJ mol-1, which is in line with physisorption.