TY  - JOUR
T1  - Anisotropic 2D ZIF-67 nanosheets for enhanced CO2/N2 separation in mixed-matrix membranes
AU  - Jeong, Sung Kuk
AU  - Hasan, Masad Mezher
AU  - Lim, Semin
AU  - Park, Jongwook
AU  - Othman, Mohd Roslee
AU  - Kim, Jinsoo
JO  - Surfaces and Interfaces
VL  - 86
SP  - 108725
PY  - 2026
DA  - 2026/04/01/
SN  - 2468-0230
DO  - https://doi.org/10.1016/j.surfin.2026.108725
UR  - https://www.sciencedirect.com/science/article/pii/S2468023026003147
KW  - 2D ZIF-67 nanosheets
KW  - CO selective membranes
KW  - Gas separation
KW  - Carbon capture
KW  - Molecular sieving
AB  - This study explored the rational design and optimization of 2D ZIF-67 nanosheets for integration into microporous mixed-matrix membranes (MMMs) to engineer high-performance gas separation technologies. By investigating the hydrothermal synthesis parameters, the study revealed that the optimal condition of 120 °C for 1 hour yielded highly crystalline nanosheets with a 1.3 μm lateral size and a large surface area of 1207 m²/g. When incorporated into a PEBAX 1657 polymer matrix, these nanosheets exhibited a horizontal orientation, which enhanced anisotropic diffusion pathways, selectively impeded N2 transport, and promoted CO2 permeability, despite the former’s more diffusive character. This alignment maximized the nanosheets' intrinsic molecular sieving properties, creating a tortuous diffusion network that significantly improved the gas selectivity. The study offered key fundamental insights into structure-property relationships governing gas transport in hybrid membranes, demonstrating that the synergy between molecular sieving, polymer rigidification, and controlled nanosheet alignment enabled an exceptional CO2/N2 ideal selectivity of 108 and a CO2 permeability of 80 Barrer, surpassing the 2008 Robeson upper boundary. Furthermore, optimization using response-surface methodology indicated that under optimal conditions i.e., N2 composition of 0.74, a feed pressure of 4.52 bar, and a stage cut of 0.85, the membrane achieved maximum N2 purity and recovery, both reaching 100%. Under operational conditions (N2 composition of 0.50, a feed pressure of 15 bar, and a stage cut of 0.15), the membrane demonstrated a maximum CO2 purity of 97.80% and a CO2 recovery of 100%. These findings highlight the potential of 2D ZIF-67-based MMMs in next-generation gas separation applications.
ER  -