Performance evaluation of graphene oxide (GO) nanocomposite membrane for hydrogen separation: Effect of dip coating sol concentration

In 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 nanocomposite membranes were prepared for hydrogen separation. To this purpose, the modified tubular ?-alumina supports were prepared by coating boehmite sol on ?-alumina support. Then, the GO top layer was coated on the modified ?-alumina support using GO colloidal sol prepared by modified hummer method. Consequently, effects of various concentrations of dip-coating sol were evaluated on GO graphene membrane performance, in terms of hydrogen separation at various pressure gradient and temperatures. Regarding to characterization analyses, uniform GO layer formation was confirmed on modified support. As a result of gas permeance test of GO nanocomposite membrane, pressure gradient effect was positive on membrane performance, while negative effect on H2/CO2 and H2/N2 selectivities was indicated versus lowest concentration of dip coating sol. On the other, for all cases, negative effect was observed for hydrogen selectivity versus temperature. In particular, for the best GO membrane sample, at room temperature and 3 bar pressure gradient, H2/CO2 and H2/N2 values were obtained 38.5 and 16.5 (H2 permeance equal 5.9 * 10-7 mol/m2 s Pa), respectively, while these parameters values at 473 K and 1 bar pressure gradient were 15.7, 10.6 (H2 permeance equal 7.6 * 10-7 mol/m2 s Pa). Moreover, regarding to effects of dip-coating sol concentration, the best choice was introduced sample 1 (with highest concentration of dip coating sol) from performance viewpoint.