Covalent Organic Frameworks in Separation

Abstract

In the wake of sustainable development, materials research is going through a green revolution that is putting energy-efficient and environmentally friendly materials and methods in the limelight. In this quest for greener alternatives, covalent organic frameworks (COFs) have emerged as a new generation of designable crystalline porous polymers for a wide array of clean-energy and environmental applications. In this contribution, we categorically review the merits and shortcomings of COF bulk powders, nanosheets, freestanding thin films/membranes, and membranes on porous supports in various separation processes, including separation of gases, pervaporation, organic solvent nanofiltration, water purification, radionuclide sequestration, and chiral separations, with particular reference to COF material pore size, host–guest interactions, stability, selectivity, and permeability. This review covers the fabrication strategies of nanosheets, films, and membranes, as well as performance parameters, and provides an overview of the separation landscape with COFs in relation to other porous polymers, while seeking to interpret the future research opportunities in this field.

Quantitative Description of the Lateral Growth of Two-Dimensional Covalent Organic Frameworks Reveals Self-Templation Effects

“…Two-dimensional covalent organic frameworks (2D COFs) are permanently porous, crystalline, macromolecular sheets that are promising for use in catalysis, , chemical sensing, − molecular separations, − energy storage, − ionic conduction, − organic electronics, ,− or biomedical devices. − To realize 2D COFs optimized for these applications, general chemical strategies are needed to produce large-area macromolecular sheets. − Groundbreaking investigations have shown that the 2D COF crystalline domain size is greatly affected by factors such as the polymerization chemistry, interlayer interactions, monomer size, presence of hydrogen bonds, and reaction conditions. , However, there is currently no unified understanding of the roles of these factors, nor are there quantitative models that can be used to guide 2D COF synthesis.…”

Chemistry of magnetic covalent organic frameworks (MagCOFs): from synthesis to separation applications

“…3 Recently, COFs have attracted researchers' interest because of their intriguing properties such as tuneable composition and high thermal and chemical stability (Fig. 1) 12,13 and have been widely used in a variety of applications including energy conversion 14,15 and storage, 16,17 gas storage, 18,19 catalysis, [20][21][22][23][24][25] optoelectronics, 26,27 sensing, 28,29 drug delivery [30][31][32] and adsorption [33][34][35] to name a few.…”

Nanoscale covalent organic frameworks as theranostic platforms for oncotherapy: synthesis, functionalization, and applications

“…43,44 Due to the diversity of organic syntheses, COFs provide promising prospects for materials design, enabling function-and applicationoriented material syntheses. Until now, COFs have been widely used for separation and analysis, [45][46][47][48][49] heterogeneous catalysis, [50][51][52] sensing, 53 optoelectronics, 54 energy and environmental science, [55][56][57][58][59] and biomedicine. 60,61 In recent years, COFs, particularly nanoscale COFs (NCOFs), have joined a huge candidate library of biomedical nanomaterials because of their following unique features.…”