Suppressing Defect Formation in Metal-Organic Framework Membranes via Plasma-Assisted Synthesis for Gas Separations
Journal
ACS Applied Materials and Interfaces
Journal Volume
13
Journal Issue
35
Pages
41904-41915
Date Issued
2021
Author(s)
Abstract
Metal-organic frameworks (MOFs) are considered as promising materials for membrane gas separations. Structural defects within a pure MOF membrane can considerably reduce its selectivity and possibly result in a nonselective separation. This work proposes a solution-phase synthesis with dielectric barrier discharge (DBD) plasma to suppress the formation of defects in the pure MOF membrane of CPO-8-BPY. Through comprehensive solid-state characterization with XRD, SEM, XPS, solid-state NMR, and XAFS, DBD plasma is demonstrated to facilitate deprotonation in the H2aip linker, which leads to a smaller and more uniform particle size of CPO-8-BPY. The narrow grain size distribution effectively reduces the pinhole-type defects in the pure CPO-8-BPY membrane and endows it with good ideal selectivity for H2/CH4 (αH2/CH4 = 28.2) and N2/CH4 (αN2/CH4 = 5.4). The selectivity for H2/CH4 of this membrane from a mixed-gas permeation test is found to be 15.4. Molecular simulations are also performed to gain insights into the gas transport properties of this MOF. The results suggest that ligand rotation plays an important role in CPO-8-BPY when being applied to the membrane separation of N2/CH4. ? 2021 American Chemical Society.
Subjects
CPO-8-BPY
dielectric barrier discharge plasma
membrane gas separation
metal-organic framework
MOF membrane
Defects
Dielectric devices
Dielectric materials
Electric discharges
Grain size and shape
Metal-Organic Frameworks
Nuclear magnetic resonance spectroscopy
Organic polymers
Organometallics
Particle size
Separation
Synthesis (chemical)
Dielectric barrier discharge plasmas
Gas transport properties
Grain size distribution
Metalorganic frameworks (MOFs)
Molecular simulations
Plasma-assisted synthesis
Solid state characterization
Solution phase synthesis
Gas permeable membranes
Type
journal article