Activated carbon (AC) adsorption processes are widely used to remove contaminants from liquids. The optimal design of the purification apparatus requires the application of a mass transfer model containing parameters that have a remarkable influence on the adsorption kinetics. The most general rate (GR) model applied up today is a differential mass transport model, which takes into account external and internal mass transfer resistance. However, the particles of AC are characterized by a wide particle size distribution (PSD) and pore diameter distribution (PDD), and that is usually not considered for the proces modeling. To have a deeper insight into the process mechanism, the adsorption kinetics were modeled with the GR model, in which PSD and PDD were included. The model was validated on the basis of experimental data of batch adsorption of the p-chlorophenol (PCP) from organic and nonorganic phases on different AC. It was found the cruitical role of PSD and PDD on adsorption curves uptake