Adsorptive removal of Erythrosine dye onto activated low cost de-oiled mustard

The present paper is aimed to investigate and develop cheap adsorption methods for colour removal from wastewater using waste material de-oiled mustard as adsorbent. De-oiled mustard, a biosorbent, was successfully utilized for removing a water-soluble xanthene dye, Erythrosine from wastewater. Kinetic studies of adsorption of Erythrosine at de-oiled mustard were carried out at 30 °C, using aqueous solutions with 5 × 10−5 M concentration of Erythrosine. The adsorption process followed a pseudo-first order model. The equilibrium process can be well described by both Freundlich and Langmuir models, at 30, 40 and 50 °C. Free energy of adsorption (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) changes were calculated to predict the nature of adsorption. The estimated values for ΔG° were −12.81 × 103 and −12.57 × 103 over activated carbon and activated de-oiled mustard at 203 K (30 °C), indicate toward a spontaneous process. The positive value for ΔH° indicates that the adsorption of Erythrosine dye to de-oiled mustard is an endothermic process.