Defect Engineering in Metal–Organic Frameworks Towards Advanced Mixed Matrix Membranes for Efficient Propylene/Propane Separation

Abstract

Highly permselective and durable membrane materials have been sought for energy-efficient C 3 H 6 /C 3 H 8 separation. Mixed-matrix membranes (MMMs) comprising ap olymer matrix and metal-organic frameworks (MOFs) are promising candidates for this application;h owever,r ational matching of filler-matrix is challenging and their separation performances need to be further improved. Here,w ep ropose an ovel strategy of "defect engineering" in MOFs as an additional degree of freedom to design advanced MMMs. MMMs incorporated with defect-engineered MOFs exhibit exceptionally high C 3 H 6 permeability and maintained C 3 H 6 / C 3 H 8 selectivity,e specially with enhanced stability under industrial mixed-gas conditions.T he gas transport, sorption, and material characterizations reveal that the defect sites in MOFs provide the resulting MMMs with not only ultrafast diffusion pathwaysb ut also favorable C 3 H 6 sorption by forming complexation with unsaturated open metal sites, confirmed by in situ FT-IR studies.M ost importantly,t he concept is also valid for different polymer matrices and gas pairs,d emonstrating its versatile potential in other fields.

Recent Advances in Mixed-Matrix Membranes for Light Hydrocarbon (C1–C3) Separation

“…Furthermore, it has been postulated that C 3 H 8 has a comparatively higher energy barrier to pass through Zr-fum-fcu-MOF crystals than does C 3 H 6 , due to the C-C bond rotation of C 3 H 8 . Similarly, Lee et al [82] developed defect-engineered MOFs derived from hydrolytically-stable [83] UiO-66 to create additional sorption sites for effective C 3 H 6 /C 3 H 8 separation; their defect-engineered UiO-66-based MMM significantly improved C 3 H 6 permeance (1.005%) relative to the control (UiO-66based MMM, 308%), without substantially jeopardizing the C 3 H 6 /C 3 H 8 selectivity. 6 [1] 0.4 [1] -15.00 [68] α-alumina Zeolite MFI -9 25 -300 6 [2] - [57] Cellulose Acetate silica 30 --0.092 0.018 -5.11 [38] Comb copolymers AgBF4/MgO nanosheet (3:7) ---11.8 [1] 0.9 [1] -13.11 [84] DBzPBI…”

Site-Specified Two-Dimensional Heterojunction of Pt Nanoparticles/Metal–Organic Frameworks for Enhanced Hydrogen Evolution

“…As a class of emerging materials, metal–organic frameworks (MOFs) have aroused great interest due to their unique structure and properties and have been widely used in the fields of energy and the environment. − In particular, MOFs can also serve as ideal precursors for constructing heterostructures. Our previous work shows that Ni-based MOFs can be converted into an NiO/MOF nanosheet (NS) heterojunction through a partial pyrolysis of the MOF, and the equilibrium between conductivity and active sites plays a vital role in the electrochemical synthesis of hydrogen peroxide .…”

Defect-enhanced selective ion transport in an ionic nanocomposite for efficient energy harvesting from moisture

“…24 For instance, defect-engineering with abundant active sites has been proven as a promising alternative to promote the molecular separation performance of MOFs-based membranes. 25,26 Room temperature ionic liquids (ILs) have received considerable attention for their use as non-volatile and inflammable electrolytes in energy storage applications such as supercapacitors and batteries. 27 They are ionically conductive, and the paired cations and anions can be exchanged with other charge-carrying species to facilitate ion or charge transport.…”

“…24 For instance, defect-engineering with abundant active sites has been proven as a promising alternative to promote the molecular separation performance of MOFs-based membranes. 25,26…”