An experimental and theoretical study is performed fur bulk separation of H₂/CO₂, mixture (70/30 volume%) by PSA process with zeolite 5A, a process widely used commercially in conjunction with the catalytic steam reforming of natural gas or naphtha. For the optimied adsorption condition, of PSA the haracteristics of adsorption/desorption characteristics have been studied through breakthrough and tlesorption experiments under various conditions. The purge-to-feed ratio is important to the H₂ product purity only at a long adsorption step time. H₂ could be concentrated from 70% in the feed to, 99.99% at H₂ recovery of 67.5%. The results of all five steps in PSA are uceessfully predicted at the LDF model considering an energy balance and nonlinear isotherm. For the nulel, the effective diffusivities (D) are obtained separately from the uptake curves of H₂ and CO₂. The Lanuir-hreundlich isotherm is used to correlate the experimental equilibrium data and is very well fitted to the results.