Isothermal Evaluation of Chemical Modification of Ricinus communis Stem Used for Adsorptive Removal of Brilliant Blue FCF Dye from Water

Abstract

Agricultural solid waste namely Ricinus communis stem was used for removing an anionic dye namely Brilliant blue FCF from synthetic waste-water. In order to enhance adsorption capacity of Ricinus communis stem, it was treated with acid and base separately and comparative adsorption studies were carried out for determining effectiveness of chemical modification in terms of sorption capacity on batch scale. Chemisorption occurred during removal of dye by adsorption as indicated by Langmuir model applicability and maximum sorption capacities were 52.4 μg/g, which is increased after acid treatment to 2445 μg/g and decreased by base treatment to 31.4 μg/g. The values of thermodynamic parameter free energy of adsorption (DGº) for these adsorbents were -1.24, -3.46 and -0.63 KJ/mol, indicating exothermic nature. Results showed that acid modification of Ricinus communis stem is more suitable for adsorptive removal of Brilliant blue FCF dye.