Adsorption of Hydroquinone in Aqueous Solution by Granulated Activated Carbon

Abstract

This paper reports the adsorptive removal of hydroquinone (HQ) from aqueous solution by granulated activated carbon (GAC). Physicochemical properties including surface area and surface texture of the GAC, before and after HQ adsorption onto GAC, were analysed by using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and Fourier transform infrared spectroscopy (FTIR). The adsorption follows pseudo-second-order kinetics. An intraparticle diffusion study reveals that the pore diffusion is not the only rate-limiting step. The effective diffusion coefficient of HQ was of the order of 3.19×10-10 m2/s. Equilibrium isotherm data were generated for HQ solutions over an initial concentration range of 0.18–9.08 mmol/L for the GAC dosage of 10 g/L at temperatures of 288, 303, and 318 K. Equilibrium data were well represented by the Temkin isotherm model. An increase in the temperature increases adsorption. The entropy change (ΔS0), heat of adsorption (ΔH0), a...