Facile Defect Engineering of Zeolitic Imidazolate Frameworks towards Enhanced C3H6/C3H8 Separation Performance
Journal
Advanced Functional Materials
Journal Volume
31
Journal Issue
47
Date Issued
2021
Author(s)
Abstract
Membrane-based olefin/paraffin separations can be an attractive alternative to the current energy-intensive cryogenic distillation for their high energy efficiency. This paper reports an amine modulator-induced defect engineering of zeolitic imidazolate framework-8 (AZIF8) nanoparticles (60?nm) for enhanced molecular sieving ability and good compatibility with various polymer matrices. It is revealed that an initial suppression of nuclei formation during synthesis enables amine modulators to deprotonate the neutral organic ligand as well as coordinate with Zn2+ ions. The resulting AZIF8s exhibit more rigid characteristics compared to the conventional ZIF-8 counterparts as demonstrated by its delayed gate opening pressure. Molecular dynamics simulations also suggest that AZIF8s exhibit a narrower pore size distribution with a smaller opening compared to the conventional ZIF-8 analogues, which makes them more suitable for size-discrimination between C3H6 and C3H8. Furthermore, the coordination of alkyl amines into frameworks allows excellent compatibility with various commercial polymer matrices. The highly concentrated 6FDA-DAM/AZIF8 (50/50 w/w) mixed matrix membrane (MMM) exhibits superior C3H6/C3H8 separation performance (C3H6 permeability of 79.38 Barrer and C3H6/C3H8 selectivity of 39.8 at single gas condition) to most existing MMMs. The structural engineering proposed herein can be applied to other metal–organic frameworks for optimizing their performance in molecular separations. ? 2021 Wiley-VCH GmbH.
Subjects
amine modulator
defect engineering
mixed matrix membrane
propylene/propane gas separation
zeolitic imidazolate framework
Amines
Chelation
Defects
Distillation
Energy efficiency
Modulators
Molecular dynamics
Pore size
Cryogenic distillations
High energy efficiency
Mixed matrix membranes
Molecular dynamics simulations
Olefin/paraffin separations
Separation performance
Zeolitic imidazolate framework-8
Zeolitic imidazolate frameworks
Gas permeable membranes
SDGs
Type
journal article