Adsorption of Rhodamine-B from aqueous solution using treated rice husk-based activated carbon

The adsorption of Rhodamine-B (RhB) onto treated rice husk-based activated carbon was investigated in this paper. The influences of initial RhB concentration, temperature and pH on dye adsorption were analyzed. Initial RhB concentration and temperature played important roles in this adsorption process, and pH had a little effect on RhB adsorption. Adsorption kinetics, equilibrium and thermodynamics study was carried out. Results demonstrated that pseudo-second order kinetic model represented the adsorption kinetics of RhB well. Adsorption equilibrium data were well described by Langmuir isotherm model. Thermodynamic parameters, including the Gibbʹs free energy change (ΔG), standard enthalpy change (ΔH) and standard entropy change (ΔS), revealed that this adsorption process was spontaneous and endothermic.