Separation of methane-nitrogen mixtures using synthesis vertically aligned carbon nanotube membranes

► Synthesis of vertically aligned carbon nanotube membranes with different CNT inner diameters via a simple CVD method. ► Separation of methane from binary mixtures of CH4/N2 using vertically aligned carbon nanotube membranes. ► Achievement of higher permeability for N2 single gas compared to Knudsen permeability.