The adsorption/desorption of phenols in aqueous solution onto coconut-shell granular activated carbon (GAC) in a liquid-solid fluidized bed adsorber approaching saturation capacity was investigated. Experiments were carried out using a 20mm id adsorber under a variety of operating conditions including GAC particle sizes (0.937, 1.524mm), GAC mass (12, 24g), influent phenol concentration (0.367-1.071 mmol dm(-3)), surface loading of GAC (2.0, 2.5 mmolg(-1)) and Liquid flow rate (0.15, 0.2, 0.35 dm(3)min(-1)). The effect of repetitive adsorption/desorption cycles on the adsorption capacity has also been examined for phenol/GAC systems. The model based on the external mass transfer with film-surface diffusion, surface adsorption equilibrium and internal mass transfer was proposed to simulate the breakthrough curves of the phenol adsorption/desorption process. Using the experimentally measured Langmuir isotherm equilibrium parameters in the model has been found to describe reasonably well the experimental results.