Adsorption of phenol from aqueous solution by using carbonised beet pulp

The adsorption studies of phenol from aqueous solution on beet pulp carbon (BPC) have been studied in the range of 25-500 mg dm−3 initial phenol concentrations and at the temperatures of 25, 40 and 60 °C. The maximum phenol adsorption capacity was obtained as 89.5 mg g−1at the temperature of 60 °C at pH = 6.0. The Freundlich and Langmuir adsorption models were used for the mathematical description of the adsorption equilibrium and it was reported that experimental data fitted very well to Freundlich model, although they could be modelled by the Langmuir equation. Batch adsorption models, based on the assumption of the pseudo-first order and pseudo-second order mechanism, were applied to examine the kinetics of the adsorption. The results showed that kinetic data were followed more closely the pseudo-second order model than the pseudo-first order. The thermodynamic parameters such as, equilibrium constant (K), Gibbs free energy changes (ΔG°), standard enthalpy change (ΔH°) and standard entropy change (ΔS°) had been determined. The results show that adsorption of phenol on BPC is an endothermic and spontaneous in nature.