Adsorption/desorption of phenols onto granular activated carbon in a liquid-solid fluidized bed

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 20 mm id adsorber under a variety of operating conditions including GAC particle sizes (0.937, 1.524 mm), GAC mass (12, 24 g), influent phenol concentration (0.367–1.071 mmol dm−3), surface loading of GAC (2.0, 2.5 mmol g−1) and liquid flow rate (0.15, 0.2, 0.35 dm3 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.