Amine-Functionalized Covalent Organic Framework for Direct Air Capture of Carbon Dioxide

[Geoengineering News]

https://pubs.acs.org/enfuem/article-abstract/doi/10.1021/acs.energyfuels.6c00750/5229473/Amine-Functionalized-Covalent-Organic-Framework?redirectedFrom=fulltext

Authors: Mohamed Essalhi; Rawan A. Al Qahtani; Aasif Helal; Mona S. Otaibi; Ammar H. Alahmed; Zain H. Yamani; Islam M. A. Mekhemer; Mahmoud M. Abdelnaby

23 July 2026

https://doi.org/10.1021/acs.energyfuels.6c00750

Abstract

Covalent organic frameworks (COFs) are promising materials for CO2 capture due to their tunable porosity and chemical versatility. Herein, we report the postsynthetic functionalization of vinylene-linked V-COF-1 with tris(2-aminoethyl)amine (TAEA), yielding an amine-appended framework (V-COF-tris) with enhanced CO2 affinity. Although amine incorporation reduces the surface area, it introduces abundant chemisorption sites that significantly improve CO2 adsorption performance. V-COF-tris exhibits CO2 uptakes of 1.80 and 2.68 mmol·g–1 at 100 kPa and 298 and 273 K, respectively, together with a high isosteric heat of adsorption (Qst = 59 kJ·mol–1), indicating a stronger CO2 affinity than the physisorption-dominated V-COF-1 (Qst = 23 kJ·mol–1). The functionalized material also demonstrates markedly enhanced CO2 selectivity, as confirmed by Ideal Adsorbed Solution Theory (IAST) calculations for CO2/N2 mixtures under both dilute (400 ppm) and concentrated conditions. Dynamic breakthrough experiments further validate the improved performance of V-COF-tris under simulated direct air capture conditions, showing prolonged CO2 retention and stable cyclic operation. Overall, this work demonstrates that postsynthetic amine functionalization effectively transforms COFs into chemisorption-driven sorbents with enhanced CO2 affinity, providing a promising strategy for low-pressure carbon capture applications.

Source: ACS Publications