Adsorption Characteristics of Coconut Shell-based Granular Activated Carbon on a Basic Dye Basic Blue 3

Abstract

In this study, adsorption characteristics of coconut shell-based granular activated carbon (CS-GAC) on Basic Blue 3 (BB3) were evaluated. As the dosage of CS-GAC increased, the removal efficiency of BB3 tended to increase and the initial dye concentration of 50 mg/L was completely removed at 0.2 g dosage. Adsorption equilibrium achieved within 270 and 420 min at the initial concentrations of 25 and 50 mg/L, respectively, and the experimental data were represented by the pseudo-second-order model. The maximum uptakes (q(max)) predicted by the Langmuir model were 34.45, 46.63 and 53.10 mg/g at 298, 308 and 318 K, respectively. The q(max) value increased as the temperature increased. Also, the Gibbs free energy (Delta G) was changed to -7.37, -8.19 and -10.40 kJ/mol with increasing temperature. The enthalpy change (Delta H) and the entropy change (Delta S) were 34.47 kJ/mol and 0.15 J/mol K, respectively. Therefore adsorption of BB3 by CS-GAC was spontaneous and endothermic.