Chinese Team Develops High-Performance Zeolite Membrane for Gas Separation

Mixing carbon dioxide with natural gas reduces its combustion efficiency and corrodes pipelines, while separating "molecular twins" — substances with the same chemical composition but different spatial structures — in oil refining has long been a tough challenge. A team of Chinese researchers has now found a solution to these industrial headaches, reported Xinhua News Agency on March 31.

Reporters learned from Nanjing Tech University on the same day that Professors Gu Xuehong and Wang Xuerui’s team has developed a scalable high-performance zeolite molecular sieve membrane through a new strategy called "embryonic zeolite-mediated membrane formation", equipping industrial gas separation with a "precision filter". The relevant research results have been published in the international academic journal Nature Communications.

Scalably preparing new separation materials and reducing gas separation energy consumption have long been a persistent problem in the energy and chemical industry. Zeolite molecular sieve membranes are covered with sub-nanometer ultra-small pores, allowing only molecules of specific sizes to pass through and thus achieving precise separation of gas mixtures.

"However, the preparation of traditional zeolite molecular sieve membranes has two major pain points," Professor Gu Xuehong explained in an interview. "First, the membrane layer is too thick, which creates high resistance and slows down gas molecule penetration; second, scaling up from laboratory-scale membrane samples to industrial-scale products is prone to defects, which greatly reduces separation efficiency."

After five years of research, the team proposed the new "embryonic zeolite-mediated membrane formation" strategy, which accurately addresses these two issues. You Lekai, first author of the paper, vividly compared the technology: "Eliminating gaps in traditional membrane layers is like paving asphalt on a gravel road; the new strategy is like using a 'needle and thread' to precisely 'stitch' zeolite molecular sieve crystals at the atomic level, forming a 'seamless' separation membrane."

Specifically, the strategy first prepares short-range ordered "embryonic zeolites" as reaction intermediates, then stitches the zeolite molecular sieve crystals into a continuous and dense membrane through condensation reactions, precisely controlling the membrane thickness to be equivalent to that of the initial seed layer.

Professor Wang Xuerui introduced three major breakthroughs achieved through this strategy. "Firstly, the membrane is thinner, with the thickness of the zeolite molecular sieve membrane reduced to 560 nanometers, effectively lowering the resistance of gas penetration," he said. "Secondly, it is more accurate, with the separation selectivity of carbon dioxide and methane reaching 158 — fewer than 2 out of 300 penetrating molecules are methane, making gas screening more precise. Thirdly, it is larger and more versatile, with a 0.5-square-meter membrane core composed of 102 40-centimeter-long hollow fiber molecular sieve membranes successfully prepared, realizing the leap from laboratory samples to industrial-grade components."

Professor Gu Xuehong noted that this achievement provides a feasible technical path for the practical application of zeolite molecular sieve membranes in industrial gas separation fields such as natural gas helium extraction, natural gas decarbonization and isomer separation. The technology is expected to promote energy conservation and efficiency improvement in the energy and chemical industry, bringing significant economic and environmental benefits.