@article{Zhang2026, 
author = {Xiaoqian Zhang and Ying Xiang and Xinxin Li and Long Pang and Xiangju Song and Chengli Jiao and Heqing Jiang},
title = {Polymer/metal-organic framework junctions in polyamide membrane via in-situ amine etching for stable CO2/N2 selectivity at elevated pressures},
year = {2026},
journal = {Nano Research},
keywords = {metal-organic frameworks, CO2 separation, polyamide composite membranes, PEI-ZIF-8 nanoparticles, in-situ amine etching},
url = {https://www.sciopen.com/article/10.26599/NR.2026.94908903},
doi = {10.26599/NR.2026.94908903},
abstract = {Polyamide thin-film composite (PA-TFC) membranes with ultrathin selective layers, fabricated via facile interfacial polymerization process, are fascinating for CO2/N2 separation. But they always suffer from drastic deterioration of CO2/N2 selectivity at elevated pressures due to CO2-induced swelling of polymer chains. Herein, we report an in-situ amine etching strategy to construct robust polyamide/PEI-functionalized ZIF-8 (PA/PEI-ZIF-8) junctions within PA-TFC membranes. In this strategy, PEI-ZIF-8 colloid is sprayed onto triethylenetetramine (TETA)-preimpregnated polysulfone substrates prior to interfacial polymerization, leading to controllable etching of PEI-ZIF-8 particles into Zn-imidazole clusters and ultra-small PEI-ZIF-8 nanocrystals. These etched species subsequently coordinate with TETA, forming highly integrated PA/PEI-ZIF-8 junctions with enhanced interfacial compatibility. Benefited by the high porosity of PEI-ZIF-8 nanocrystals and excellent interfacial compatibility, the optimized composite membrane realizes a CO2 permeance of 478 GPU and a CO2/N2 selectivity of 60.3. Notably, owing to the rigidity of PEI-ZIF-8 nanocrystals and coordination interactions between PEI-ZIF-8 and polyamide chains, the PA/PEI-ZIF-8 junctions effectively improve the anti-swelling property of composite membranes. Contrary to reduced CO2/N2 selectivity of pristine PA membrane at elevated pressures, the CO2/N2 selectivity of composite membrane remains stable as the feed gas pressure increases from 1 to 4 bar. This work provides a novel strategy for fabricating robust PA-TFC membranes for pressurized CO2 separation.}
}