In the last five recent years, molecular-sieve Graphene Oxide (GO) membranes have shown a great potential to realize high-flux and high-selectivity mixture separation, at low energy cost. Hence, in this study, GO nano-composite membranes were fabricated on modified gamma-alumina tubes for hydrogen separation. As a high-performance process, H-2-permselective GO membrane derived from graphite source was developed by using a modified hummer method. In fact, the GO nanocomposite membranes, referred to here as carbon membranes, were prepared via vacuum dip coating of the modified gamma-alumina tubes using single-layer GO solution. Special attention was devoted to obtain high H-2/CO2 selectivity, high H-2 permeance, and good stability in separation process. Hence, the effects of the operating conditions (temperature, and pressure on quality and performance of the GO membranes) were investigated. At the best condition, the synthesized GO membrane exhibited good H-2/CO2 selectivity (> 57) and high H-2 permeance (in the order of 7.9 x 10(-7) mol Pa-1 m(-2) s(-1)). Moreover, it was found that the GO membrane selectivities (H-2/CO2 and H-2/N-2) were decreased by temperature increasing, while selectivity trends were improved by increasing pressure gradient. It should be noted that all permeation tests were reported after time durability of around 48 h.