Yang, Guiping; Yao, Junxuan; Wen, Yuxin; Liu, Shuning; Mu, Yuhe; Fan, Jingrui; Liu, Xiaobo; Yu, Chengbing; Zeng, Gaofeng

JOURNAL OF MEMBRANE SCIENCE

2025, ,

Yang, Guiping; Yao, Junxuan; Wen, Yuxin; Liu, Shuning; Mu, Yuhe; Fan, Jingrui; Liu, Xiaobo; Yu, Chengbing; Zeng, Gaofeng

Two-dimensional covalent organic frameworks (2D COFs) demonstrate significant potential for gas separation due to their crystalline nanochannels and structural tunability, yet practical implementation is constrained by inherent pore size limitations (>0.8 nm) and processing challenges. Herein, we engineered a Tp-PaSO3H-COF-PDA composite membrane through an electrostatic-driven infusion of dopamine (DA) into solvothermally synthesized Tp-PaSO3H-COF channels on alpha-Al2O3 supports. The resulting composite membranes own dual-function separation mechanisms. Pore size reduction enhances molecular sieving capabilities, resulting in an improvement in the separation performance of H-2/N-2 and H-2/CH4. Concurrently, amino-rich polydopamine (PDA) networks provide specific CO2 affinity sites that selectively hinder CO2 transport, leading to further improved H-2/CO2 separation performance. The membrane demonstrates operational stability under varying transmembrane pressures, feed compositions, temperatures, and extended operation. This confinement strategy transforms conventional covalent organic frameworks into precision separation platforms for sustainable hydrogen purification.