Enabling Fluorinated MOF‐Based Membranes for Simultaneous Removal of H₂S and CO₂ from Natural Gas

Abstract

Membrane-based gas separations are energy efficient processes; however, major challenges remain to develop highperformance membranes enabling replacement of conventional separation processes. Here, a new fluorinated MOF-based mixedmatrix membrane is reported, which is formed by incorporating the MOF crystals into selected polymers via a facile mixed-matrix approach. By finely controlling the molecular transport in the channels through MOF apertures tuned by metal pillars and at the MOFpolymer interfaces, the resulting fluorinated MOF-based membranes exhibit excellent molecular sieving properties. We show that these materials significantly outperform state-of-the-art membranes for simultaneous removal of H 2 S and CO 2 from natural gas-a challenging and economically-important application. The robust fluorinated MOFs (NbOFFIVE-1-Ni, AlFFIVE-1-Ni), with tunable channel apertures provided by tuning the metal pillars and/or organic linker, pave a new avenue to efficient membrane separation processes that require precise discrimination of closely sized molecules.

Kinetic stability of metal–organic frameworks for corrosive and coordinating gas capture

“…The Ni 2+ -based NbOF5 2and AlF5 2--pillared materials 165 significantly increase both the selectivity and the permeability of the host polymer membrane for H2S, and both materials remain stable by PXRD after exposure to 14 bar H2S. 166 The Ni 2+ materials are more stable to H2S, as well as to water, than analogous Cu 2+ frameworks employing SiF6 2as the pillar, with Ni(py)(AlF5) stable to 15 cycles of water uptake. 167,168 MOFs employing more strongly donating azolate ligands have not been widely explored for H2S capture.…”

Theoretical Prediction and Experimental Evaluation of Topological Landscape and Thermodynamic Stability of a Fluorinated Zeolitic Imidazolate Framework

“…etry-optimize TEP 16.11., 41 us EDC. 42 The I-c of Zn(CF 3 Im) 2 m); (b) synthe of herein pred SOD-Zn(CF 3 Im utationally sc topological pr reported ZIF, m) 2 , Figure 1) of the recent s. [29][30][31][32][33][34][35][36][37] Dissolution enthalpies of Zn(CF 3 Im) 2 frameworks were measured with a CSC 4400 isothermal microcalorimeter operating at 25 C. A pellet (3-5 mg) of each chemical used in the thermodynamic cycle (see SI) was hand-pressed, weighed using a Mettler microbalance, and dropped into 25.0 g of isothermally equilibrated 5 M HCl aqueous solution inside a 50 mL Teflon cell of the calorimeter. After each experiment the cell was reassembled with fresh solvent.…”

Metal Organic Framework — Based Mixed Matrix Membranes for Carbon Dioxide Separation: Recent Advances and Future Directions

“…Although various MOFs have been studied for the fabrication of defect-free MMMs, challenges remain such as control of interface voids and the aggregation of MOF crystals in the polymer matrix (Mahdi and Tan, 2016 ; Wang Z. et al, 2016 ). In this regard, functionalized MOFs or post surface-modified MOFs are employed to improve the interfacial interaction between MOFs and the polymer matrix, as well as to tune filler interaction with CO 2 (Liu et al, 2018a , b , c ). MOF-based MMMs have been prepared using functionalized MOFs and post-synthetic modified (PSM) MOFs through in situ and ex-situ methods.…”