Recent progress in developments of membrane materials and modification techniques for high performance helium separation and recovery: A review

Helium is a valuable gas with unique properties and applications and still the prominent industrial source of helium is natural gas. Because of several advantages of membrane-based separation processes over conventional methods as well as the lack of a comprehensive scientific report, the present study aims to investigate the advances in design and modification of organic and inorganic membranes and materials including pure polymers, mixed matrix membranes, polymer blends, copolymers, ceramics as well as carbon molecular sieves for separation and recovery of helium from methane and nitrogen. In overall, inorganic membranes such as silica have shown good performance in helium separatibn, but production of such membranes has not yet become viable on the commercial scale. On the other hand, polymeric membranes are low-priced, but their performance is relatively low with much room for improvements. One of the most effective methods to enhance the performance of these membranes is synthesizing copolymer membranes consisting of alternatively flat and bulky segments. Also, alternations in the membrane configurations as well as hybridization of membranes with cryogenic and pressure swing adsorption processes are among the valuable options for optimizing techno-economical viability of helium separation and purifcation.