Controllable and Rapid Synthesis of Conjugated Microporous Polymer Membranes via Interfacial Polymerization for Ultrafast Molecular Separation

Abstract

Conjugated microporous polymers (CMPs) featuring a well-structured microporosity are desirable molecular sieving materials, but most are fabricated under harsh synthesis conditions (e.g., high temperature and pressure) and are insoluble, which is challenging for processing them into continuous membranes. Herein, in situ formation of imine-linked, 31-nm-thick CMP nanofilms supported on porous polymeric substrates via catalysis diffusion-controlled interfacial polymerization (IP) under mild conditions is reported. The diffusion of catalyst acetic acid (AcOH) from the water phase to the interface enables acceleration of the aldehyde-amine condensation from the oil phase and thus the formation of CMP nanofilms within 10 min. The micropore size and thickness of CMP membranes were feasibly regulated by rational utilization of molecular ligands and control of IP parameters. Importantly, introducing hydroxyl groups adjacent to aldehyde enlarges CMP pore apertures from 1.0 to 1.7 nm due to the reduced reactivity induced by steric hindrance and the formed intramolecular hydrogen bonds. The newly synthesized 2,5-dihydroxyterephthaldeyde–m-phenylenediamine membranes display an extraordinarily high water permeance (240.0 L m–2 h–1 bar–1) and an excellent brilliant blue R (825.9 Da) rejection (i.e., 98.3%). In addition, the CMP membranes achieve an unprecedented sieving capability for both dye/dye and dye/divalent salt mixtures. This catalysis diffusion-controlled, interface-confined polymerization means may enable the development of new coherent microporous organic polymer films with potential for water purification, adsorption, and gas purification.

Visible-light-driven photoelectrochemical sensor based on conjugated microporous polymer-grafted graphene for o-aminophenol detection

“…The result is consistent with the previous research studies. 35 The composition and chemical states of the surface elements of CMP-rGO were determined by XPS. Fig.…”

Ionic Control of Functional Zeolitic Imidazolate Framework-Based Membrane for Tailoring Selectivity toward Target Ions

“…The excess discharges of wastewater containing different ionic species cause various environmental issues, including introducing toxicants to aquatic ecosystems and water eutrophication, and posing a significant threat to drinking water quality. − The presence of physically similar or coexisting ionic species in the aqueous environment poses a critical challenge to environmental sustainability . To ensure the sustainable development of water treatment, converting these wastewaters to resources to obtain valuable salt products from the harmful discharges is highly attractive. , Therefore, highly efficient separation technologies for these ionic species are regarded as most promising to obtain the purified ionic products. , Of the approaches presently available, membrane technologies, such as nanofiltration (NF) and electrodialysis (ED), have been widely used for ion separation because of their economic and environmental friendliness, eco-friendly potential, and low energy consumption. − In particular, ED membranes, which can be classified into anion exchange membranes (AEMs), cation exchange membranes (CEMs), and bipolar membranes, mainly focus on separating ions and producing ionic products from various aqueous environments . Compared to the NF process, the ED can avoid high concentration gradient and osmotic pressure.…”

Charged cyclodextrin membranes for precise molecular sieving

“…10 Molecular sieving membranes can distinguish specific molecules from a solution mixture based on their molecular weight or shape. 11,12 Generally, these molecular sieving membranes involved precisely designed structures with adjustable and uniform pore channels. 13–17…”

“…10 Molecular sieving membranes can distinguish specic molecules from a solution mixture based on their molecular weight or shape. 11,12 Generally, these molecular sieving membranes involved precisely designed structures with adjustable and uniform pore channels. [13][14][15][16][17] Currently, one of the most popular molecular separation membranes with a well-dened pore size and pore size distribution is prepared from nanosheet-based materials.…”

“…[23][24][25][26] Microporous organic polymers and molecules that combine modiable chemical functionalities and intrinsic microporosity are highly desirable for fabricating next-generation molecular sieving membranes. 12 Among different candidates, cyclodextrins (CDs) with a unique hollow structure can serve as the appropriate membrane materials. 27,28 The internal cavity size of a b-CD molecule ranges from 6.0 Å to 7.8 Å, which supplies tremendous transport routes to the selective layer with its specic cavity structure, 29,30 while smaller molecules could pass through and the larger molecules could be rejected.…”