doi:10.1016/j.seppur.2025.135596engRefaat, DaliaAmenakpor, JackingCoronas, JoaquínZornoza, BeatrizInnovative starch-PVA membranes incorporating amino-functionalized Zeolitic Imidazolate frameworks for CO2/CH4 separationART-2025-145785The growing need for efficient CO2 separation in natural gas purification and carbon capture has driven the advancement of high-performance membrane technologies. This study incorporates the zeolitic imidazolate framework ZIF-8-NH2 into blends of polysaccharide starch and polyvinyl alcohol (PVA) to fabricate eco-friendly membranes. These materials, prepared as dense mixed matrix membranes (MMMs) and thin-film nanocomposite (TFN) membranes, offer a sustainable solution for CO2/CH4 separation. The integration of ZIF-8-NH2 nanoparticles, recognized for their high crystallinity and surface area and selective adsorption capacity into the starch–PVA matrix (33/67 blend ratio), significantly enhances CO2 permeability, increasing from 124 to 188 Barrer at 10 wt% loading, while preserving high CO2/CH4 selectivity (14.1 for the pristine blend and 16.5 for the MMM). For TFNs, a 9/91 starch-PVA matrix with 15 wt% ZIF-8-NH2 incorporated into the selective layer resulted in the best conditions. This architecture provided robust mechanical stability and high separation performance, yielding a CO2 permeance of up to 208 GPU and a CO2/CH4 selectivity of 26.9 at 3 bar feed pressure, nearly doubling the selectivity compared to the dense biopolymer blend. This work highlights the potential of renewable, starch-based materials in membrane-based gas separation, contributing to sustainable solutions for natural gas purification and carbon capture.2025http://zaguan.unizar.es/record/16370810.1016/j.seppur.2025.135596http://zaguan.unizar.es/record/163708oai:zaguan.unizar.es:163708info:eu-repo/grantAgreement/ES/AEI/RYC2022-0381393-Iinfo:eu-repo/grantAgreement/ES/DGA/T68-23Rinfo:eu-repo/grantAgreement/ES/MICINN/PID2022-138582OB-I00info:eu-repo/grantAgreement/EUR/MICINN/TED2021-130621B-C4info:eu-repo/grantAgreement/ES/MICIU/CEX2023-001286-SSeparation and Purification Technology 382, Part. 1 (2025), 135596 [14 pp.]by-nc-ndhttps://creativecommons.org/licenses/by-nc-nd/4.0/deed.esinfo:eu-repo/semantics/openAccess