Research Progress in Microporous Materials for Selective Adsorption and Separation of Methane from Low-Grade Gas.

Given that methane (CH) and nitrogen (N) have similar properties, achieving high-purity enrichment of CH from nitrogen-rich low-grade gas is extremely challenging and is of great significance for sustainable development in energy and the environment. This paper reviews the research progress on carbon-based materials, zeolites, and MOFs as adsorbent materials for CH/N separation. It focuses on the relationship between the composition, pore size, surface chemistry of the adsorbents, CH/N selectivity, and CH adsorption capacity. The paper also highlights that controlling pore size and atomic-scale composition and optimizing these features for the best match are key directions for the development of new adsorbents. Additionally, it points out that MOFs, which combine the advantages of carbon-based adsorbents and zeolites, are likely to become the most promising adsorbent materials for efficient CH/N separation.