Dynamic adsorption parameters of CH4, CO, CO2 and N-2 gas mixtures on a fixed bed of Ai-Dag (Azerbaijan) natural clinoptilolite were identified. The effects of adsorbate concentration on the effective diffusion coefficient and overall mass-transfer coefficient were determined. Also, the change of clinoptilolite activity with time during CO2 adsorption was studied. A system of equations describing the changes of effective diffusion and mass-transfer coefficients as functions of time was proposed and could be used to design the best industrial adsorbers under unsteady process conditions.