We propose a simple but very efficient method for the modeling of the multi-solute adsorption from liquids. The thermodynamic model used is an extension of a classical model for non-ideal multi-solute adsorption in the solid phase for binary and ternary solute systems. An algorithm is proposed for the solution of the constitutive equations that allows for the flexibility of the originally constant parameters involved in the equations correlating the Gibbs energy with composition in the solid phase. Using our own experimental data for the adsorption of paraxylene, metaxylene and ethylbenzene on BaX zeolite, the method is tested for binary and ternary solute systems using isooctane as solvent. The model is able to predict the separation factors of the binary and ternary solutes adsorption systems with a high accuracy. (C) 2015 Elsevier B.V. All rights reserved.