Post-synthetic modification of highly stable UiO-66-NH2 membranes on porous ceramic tubes with enhanced H2 separation

• Published in: Microporous and mesoporous materials 2021-01, Vol.313, p.110823, Article 110823
• Main Authors: Guo, Hao, Liu, Jiaqin, Li, Yanhong, Caro, Jürgen, Huang, Aisheng
• Format: Article
• Language: English
• Subjects: Hydrogen purification; Metal-organic frameworks membranes; Post-synthetic modification (PSM); UiO-66-NH2 membrane
• ISSN: 1387-1811; 1873-3093
• DOI: 10.1016/j.micromeso.2020.110823

Due to their rationally controlled pore size and easy functionalization, metal-organic frameworks (MOFs) are a promising candidate for membrane separation. As one of the most stable MOFs, UiO-66 has attracted intense attention for the preparation of molecular sieving membranes. A new post-synthesis modification (PSM) strategy was developed to enhance the separation selectivity of supported UiO-66-NH2 membranes on porous ceramic tubes called UiO-66-NH2@SA by using salicylaldehyde (SA) modification. The mixed gas separation factors of H2/CO2 and H2/CH4 can be improved due to constrictions of the pore size through reaction of –NH2 with SA giving iminophenol moieties. Notably, SA-modified UiO-66-NH2 membranes are rather stable, at a high operation temperature of 200 °C and 1 bar, mixture separation factors of 11.3 for H2/CO2 and 22 for H2/CH4 can be obtained. Further, no obvious performance degradation has been observed after 3 months storing in air. This high stability of UiO-66-NH2@SA membrane could provide possibility for the industrial applications of hydrogen separation and purification. [Display omitted] •Dense UiO-66-NH2 membranes are prepared on APTES-modified macroporous α-Al2O3 tubes.•A new post-synthesis modification strategy was developed to enhance the separation selectivity of UiO-66-NH2 membranes.•The developed UiO-66-NH2@SA membranes show high separation performances for hydrogen purification.