Equilibrium isotherm analyses and thermodynamic studies of the removal of basic dye from solution using castor seed shell

摘要

The equilibrium isotherm analysis and the thermodynamics of the sorption of basic dye by Castor Seed Shell (CSS) was investigated. Isotherm experiments were conducted and the data obtained were fitted into different equilibrium isotherm equation viz: Langmuir I and II; Freundlich; Dubinin-Radushkevich (D-R); Temkin; Harkins -Jura and Halsey isotherm equation. Freundlich, Langmuir (I and II). The Halsey isotherm equations gave the best correlations (r2) than the other isotherm equations fitted with the experimental data. The relationship between the dimensionless parameter, K_R, and initial concentration, C_o, showed that the sorption of MB was favored at higher initial dye concentration and CSS dosages than the lower ones. The thermodynamic analysis showed that the sorption is spontaneous and endothermic. The prospects of regenerating the CSS was studied using four different eluting solvents in a batch desorption studies. The results of the batch desorption studies showed that both chemisorptions and ion-exchange played prominent role in the sorption process.