Synthesis and Helium Separation Performance of Polycrystalline Membranes of the High Precision Molecular Sieve MIL-116(Ga)

Synthesis and Helium Separation Performance of Polycrystalline Membranes of the High Precision Molecular Sieve MIL-116(Ga) | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Synthesis and Helium Separation Performance of Polycrystalline Membranes of the High Precision Molecular Sieve MIL-116(Ga) Alexander Knebel, Ayisha Komal, Laura Calderón-Rodríguez, Franziska Scheffler, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7196877/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 09 Apr, 2026 Read the published version in Communications Materials → Version 1 posted You are reading this latest preprint version Abstract Helium is a finite but essential resource with important applications in medicine, research and aerospace. Conventional He-upgrading from natural methane gas (CH 4 ) is done by cryogenic distillation. This study presents energy efficient He-upgrading by membrane separation using the "dense" metal-organic framework (MOF) MIL-116(Ga), which enables high precision molecular sieving of non-adsorptive gases. MIL-116(Ga) membranes were synthesized on alumina after developing a method to homogeneously intergrow the MOF into a polycrystalline film. Single gas permeation experiments reveal exceptional ideal selectivity of α ideal (H 2 /CH 4 ) = 116 and α ideal (He/CH 4 ) = 78. In mixed gas permeation, the separation selectivity surpasses α ideal (He/CH 4 ) = 200 in a 1:1 mixture. Mixed-gas tests at realistic 4:96 He/CH 4 feed gas composition reached a selectivity of α(He/CH 4 ) = 31.2 and permeance for He of P(He) = 1800 GPU. Electron microscopy uncovered a complex, grain-boundary microstructure, which limits perfect molecular sieving but still enables superior separation performance. This work demonstrates that dense MOFs, at the example of MIL-116(Ga) enables high performance He-upgrading, setting a new benchmark amongst reported MOF-based membranes. The paper highlights the potential of dense MOFs for the separations of small, non-adsorptive gases and the need to address grain boundary diffusion in polycrystalline MOF membranes. Physical sciences/Energy science and technology/Carbon capture and storage Physical sciences/Chemistry/Environmental chemistry/Pollution remediation Physical sciences/Chemistry/Chemical engineering Full Text Additional Declarations There is NO Competing Interest. Supplementary Files SIPolycrystMIL11623072025.docx Supporting Information Cite Share Download PDF Status: Published Journal Publication published 09 Apr, 2026 Read the published version in Communications Materials → Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7196877","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":491771085,"identity":"abd7b5a7-41f8-483e-b6ed-0d7bd51ecf97","order_by":0,"name":"Alexander 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Conventional He-upgrading from natural methane gas (CH\u003csub\u003e4\u003c/sub\u003e) is done by cryogenic distillation. This study presents energy efficient He-upgrading by membrane separation using the \"dense\" metal-organic framework (MOF) MIL-116(Ga), which enables high precision molecular sieving of non-adsorptive gases. MIL-116(Ga) membranes were synthesized on alumina after developing a method to homogeneously intergrow the MOF into a polycrystalline film. Single gas permeation experiments reveal exceptional ideal selectivity of α\u003csub\u003eideal\u003c/sub\u003e(H\u003csub\u003e2\u003c/sub\u003e/CH\u003csub\u003e4\u003c/sub\u003e)\u0026thinsp;=\u0026thinsp;116 and α\u003csub\u003eideal\u003c/sub\u003e(He/CH\u003csub\u003e4\u003c/sub\u003e)\u0026thinsp;=\u0026thinsp;78. In mixed gas permeation, the separation selectivity surpasses α\u003csub\u003eideal\u003c/sub\u003e(He/CH\u003csub\u003e4\u003c/sub\u003e)\u0026thinsp;=\u0026thinsp;200 in a 1:1 mixture. Mixed-gas tests at realistic 4:96 He/CH\u003csub\u003e4\u003c/sub\u003e feed gas composition reached a selectivity of α(He/CH\u003csub\u003e4\u003c/sub\u003e)\u0026thinsp;=\u0026thinsp;31.2 and permeance for He of P(He)\u0026thinsp;=\u0026thinsp;1800 GPU. Electron microscopy uncovered a complex, grain-boundary microstructure, which limits perfect molecular sieving but still enables superior separation performance. This work demonstrates that dense MOFs, at the example of MIL-116(Ga) enables high performance He-upgrading, setting a new benchmark amongst reported MOF-based membranes. The paper highlights the potential of dense MOFs for the separations of small, non-adsorptive gases and the need to address grain boundary diffusion in polycrystalline MOF membranes.\u003c/p\u003e","manuscriptTitle":"Synthesis and Helium Separation Performance of Polycrystalline Membranes of the High Precision Molecular Sieve MIL-116(Ga)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-30 12:28:46","doi":"10.21203/rs.3.rs-7196877/v1","editorialEvents":[],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"communications-materials","isNatureJournal":true,"hasQc":false,"allowDirectSubmit":false,"externalIdentity":"commsmat","sideBox":"Learn more about [Communications Materials](https://www.nature.com/commsmat/)","snPcode":"","submissionUrl":"","title":"Communications Materials","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"ejp","reportingPortfolio":"Communications Series","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"aa9da744-089a-4a68-9304-3445ec22eeda","owner":[],"postedDate":"July 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[{"id":52205911,"name":"Physical sciences/Energy science and technology/Carbon capture and storage"},{"id":52205912,"name":"Physical sciences/Chemistry/Environmental chemistry/Pollution remediation"},{"id":52205913,"name":"Physical sciences/Chemistry/Chemical engineering"}],"tags":[],"updatedAt":"2026-04-17T07:08:05+00:00","versionOfRecord":{"articleIdentity":"rs-7196877","link":"https://doi.org/10.1038/s43246-026-01156-3","journal":{"identity":"communications-materials","isVorOnly":false,"title":"Communications Materials"},"publishedOn":"2026-04-09 04:00:00","publishedOnDateReadable":"April 9th, 2026"},"versionCreatedAt":"2025-07-30 12:28:46","video":"","vorDoi":"10.1038/s43246-026-01156-3","vorDoiUrl":"https://doi.org/10.1038/s43246-026-01156-3","workflowStages":[]},"version":"v1","identity":"rs-7196877","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7196877","identity":"rs-7196877","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}