Assembling covalent organic framework membranes with superior ion exchange capacity

Abstract

Ionic covalent organic framework membranes (iCOFMs) hold great promise in ion conduction-relevant applications because the high content and monodispersed ionic groups could afford superior ion conduction. The key to push the upper limit of ion conductivity is to maximize the ion exchange capacity (IEC). Here, we explore iCOFMs with a superhigh ion exchange capacity of 4.6 mmol g−1, using a dual-activation interfacial polymerization strategy. Fukui function is employed as a descriptor of monomer reactivity. We use Brønsted acid to activate aldehyde monomers in organic phase and Brønsted base to activate ionic amine monomers in water phase. After the dual-activation, the reaction between aldehyde monomer and amine monomer at the water-organic interface is significantly accelerated, leading to iCOFMs with high crystallinity. The resultant iCOFMs display a prominent proton conductivity up to 0.66 S cm−1, holding great promise in ion transport and ionic separation applications.

Extremely Stable Sulfuric Acid Covalent Organic Framework for Highly Effective Ammonia Capture†

“…The powder X‐ray diffraction (PXRD) of TpBD‐(SO 3 H) 2 (Figure 2a) showed diffraction peaks at about 3.3 o , 6.0 o , 6.8 o , corresponding to (100), (110), and (200) planes, respectively, which is consistent with the simulated pattern based on the AA structural model. [ 26b ] The successful synthesis of TpBD‐(SO 3 H) 2 was further indicated by Fourier transform infrared (FT‐IR), and 13 C cross‐ polarization magic‐angle spinning nuclear magnetic resonance ( 13 C CP‐MAS NMR) measurements. As shown in Figure S3, the new characteristic peaks appeared at about 1082 and 1022 cm –1 (O=S=O), indicating the existence of –SO 3 H groups in TpBD‐ (SO 3 H) 2 .…”

“…[ 23 ] Therefore, a highly stable sulfonic acid COF, namely TpBD‐(SO 3 H) 2 , was synthesized by 1,3,5‐triformylphloroglucinol (Tp) and 4,4'‐diaminobiphenyl‐3,3'‐disulfonic acid (BD‐(SO 3 H) 2 ) under solvothermal conditions. [ 26 ] The resulting TpBD‐(SO 3 H) 2 not only exhibits high structural stability in water and acidic conditions, but also shows high ammonia capacity of 11.5 mmol·g −1 at 298 K and 1 bar, which is higher than those of the benchmark adsorbents including MCM‐41 (7.9 mmol·g −1 ), [ 27 ] and 13X zeolite (9.0 mmol·g −1 ). [ 28 ] Since its high chemical stability as well as superior NH 3 uptake capacity, TpBD‐(SO 3 H) 2 illustrates great potential application for NH 3 capture under harsh conditions, making it among the best in all high stable NH 3 adsorbents up to date.…”

Facile construction of a highly proton-conductive matrix-mixed membrane based on a –SO3H functionalized polyamide

“…In order to fabricate the polyamide-based proton-conductive electrolytes, a –SO 3 H functionalized organic diamine, 4,4-diamino-2,2-biphenyldisulfonic acid, 36–38 and a triple-symmetrical 1,3,5-benzenetricarbonylchloride were selected as the precursors. Then, the simple process of one-pot polymeric acylation was followed (Fig.…”

Interfacial Synthesis of 2D COF Thin Films

“…Zhongyi Jiang et al prepared ionic covalent organic framework membranes (iCOFMs) with ultrahigh ion exchange capacity via the double-activation interfacial polymerization strategy (Figure 6d). Brønsted acid and Brønsted base activate aldehyde monomers and amine monomers with sulfonic groups in aqueous and organic phases, respectively [31]. After the double activation of acid and base, the monomer can react quickly at the interface and form iCOFMs with high crystallinity.…”