A BZSM-5 zeolite membrane layers supported on a porous tubular alpha alumina support were prepared by hydrothermal synthesis. Permeation of single and binary mixture of normal pentane (nC(5)) and 2-methylbutane (2 MB) through BZSM-5 zeolite membrane was studied as a function of total pressure, temperature and feed composition using total pressure difference and concentration gradient methods. The nC(5)/2 MB selectivity decreased with increasing of temperature. The rapid decrease in separation selectivities with increase in temperature indicated that preferential adsorption was responsible for the selectivity. The selectivity decreased as the feed pressure increased in total pressure difference method. The performance of membrane in concentration gradient method is higher than that in total pressure drop method. It can be addressed by decreasing of non-zeolite effect on membrane permeation in the concentration gradient method. In addition, in contrast of pressure drop method, the nC(5)/2 MB selectivity of membrane increased with increase in feed pressure for concentration gradient method. (C) 2012 Elsevier B.V. All rights reserved.