Polyamide Covalent Organic Framework Membranes for Molecular Sieving

Abstract

Polyamide is an important class of membrane materials for separation technology. The polyamide membranes currently used are amorphous, and thus, their pore structures are disordered, which inevitably decreases their performance in separation. Herein, we report a new type of polyamide membranes which are fabricated from amide-linked covalent organic frameworks (COFs), a class of crystalline porous polymers with well-ordered pore structures. Thanks to the structural advantages of amide-linked COFs, the polyamide COF membranes not only exhibit high permeability (482.3 L m–2 h–1 bar–1 to water) and high rejection rate to organic dyes (>99% for methylene blue) but also display excellent stability under a harsh environment. The vantage of the polyamide COF membranes is also manifested by the comparison of their mechanical property, stability, and separation performance with that of the membranes fabricated from the COFs having the same building blocks but linked with imine and amine linkages. This work demonstrates that amide-linked COFs, which combine the structural features of COFs and polyamide, could be a new type of advanced materials for the fabrication of high-performance separation membranes.

Covalent Organic Framework Membrane with Angstrom Discrimination in Pore Size for Highly Permselective Ionic Liquid Nanofiltration

“…The nanoindentation technique was employed to analyze the nanomechanical properties of these COF membranes. 56 As depicted in Figure 5d, all of the load−depth (P−h) curves…”

“…The nanoindentation technique was employed to analyze the nanomechanical properties of these COF membranes . As depicted in Figure d, all of the load–depth ( P – h ) curves exhibit no noticeable discontinuities with increasing load, suggesting the absence of local plastic deformation during testing.…”

A Critical Review on Current Challenges in the Analysis of Microplastics in Food Samples

“…Synthetic polyamide is used to create nylon membranes. 100 Although, there is a range of pore widths that can successfully catch MPs, they vary in size. For the purpose of removing MPs from water samples, nylon membranes are utilized.…”

Interfacial Synthesis of an Ultrathin Two-Dimensional Polymer Film via [2 + 2] Photocycloaddition

“…According to previous reports, several reaction types have been successfully applied to the interfacial synthesis of 2D COFs or 2D polymer films, such as Schiff base condensation, azide-alkyne cycloadditions, Glaser-Hay coupling reactions, [2 + 2] photocycloaddition, and so on [ 48 , 49 , 50 , 51 ]. Dichtel’s groups reported the interfacial polymerization of monomers capable of forming imine-linked 2D COF films at liquid/liquid interfaces.…”