Missing‐linker Defects in Covalent Organic Framework Membranes for Efficient CO₂ Separation

Abstract

Covalent organic framework (COF) membranes with tunable ordered channels and free organic groups hold great promise in molecular separations owing to the synergy of physical and chemical microenvironments. Herein, we develop a defect engineering strategy to fabricate COF membranes for efficient CO 2 separation. Abundant amino groups are in situ generated on the COF nanosheets arising from the missing-linker defects during the reactive assembly of amine monomer and mixed aldehyde monomers. The COF nanosheets are assembled to fabricate COF membranes. Amino groups, as the CO 2 facilitated transport carriers, along with ordered channels endow COF membrane with high CO 2 permeances exceeding 300 GPU and excellent separation selectivity of 80 for CO 2 /N 2 , and 54 for CO 2 /CH 4 mixed gas under humidified state. Our defect engineering strategy offers a facile approach to generating free organic functional groups in COF membranes and other organic framework membranes for diverse chemical separations.

Breakthrough applications of porous organic materials for membrane-based CO2 separation: a review

“…Figure 3 depicts the molecular structure of different COFs. Various features such as custom-made properties (achieved by functionalization), structural versatility and uniform pore size distribution have authorized the COFs to be used in an extensive range of applications like membrane-based gas separation and cancer treatments ( Guan et al, 2020 ; Sharma et al, 2020 ; Guo et al, 2022 ). The remarkable development of COFs is prominently justified because of their self-healing capability and thermodynamically manageable covalent chemistry, which eventuate in long-range crystalline structure ( Pachfule et al, 2018/01 ).…”

Computational Simulation of CO2/CH4 Separation on a Three-Dimensional Cd-Based Metal–Organic Framework

“…Therefore, it is a vital issue to develop new materials that can efficiently store and separate CO 2 gas with suitable particle size, high porosity, and stability. The CO 2 adsorption and separation on zeolites, active carbons, aluminophosphates, clays, mesoporous molecular sieves, covalent organic frameworks (COFs), and metal–organic frameworks (MOFs) have attracted the attention of many scientists. − It is a commonly accepted fact that separating CO 2 from other gas molecules, such as CH 4 or N 2 , is challenging due to the slight difference in their molecular sizes. The molecular-level design and modification of materials to regulate pore size is a challenging task, and therefore, the development of separation materials with a high affinity for CO 2 is pursued as a more feasible approach.…”

Developing Mixed Matrix Membranes with Good CO2 Separation Performance Based on PEG-Modified UiO-66 MOF and 6FDA-Durene Polyimide

“…Concurrently, there has been a surge in research focused on gas separation involving porous materials with varying pore sizes, including zeolites [8,9], metal-organic frameworks (MOFs) [10][11][12][13], covalent organic frameworks (COFs) [14][15][16], and porous organic polymers [17,18]. By incorporating these porous materials as additives into organic polymer membranes, a class of materials known as mixed matrix membranes (MMMs) can be fabricated.…”