Selective Adsorption of CHF3 over N2 in a Scalable Aluminum Fumarate Metal–Organic Framework

Abstract

The selective separation of CHF3 from N2 is of practical importance for both greenhouse gas mitigation and resource recovery. In this work, a metal–organic framework that is based on aluminum, Al-Fum, was investigated as an adsorbent for CHF3/N2 separation. The synthesis of Al-Fum was accomplished via a simple approach. Moreover, a single batch can readily achieve the hundred-gram scale in a green manner. The material is characterized by a microporous structure, featuring a pore aperture of roughly 5.6 × 6.0 Å, which is favorable for thermodynamically selective adsorption. The adsorption uptake for CHF3 reaches 73.56 cm3 g–1 at 298 K and 100 kPa, whereas the uptake of N2 is only 5.97 cm3 g–1. The calculated isosteric heat of adsorption for CHF3 is 27.04 kJ mol–1, higher than that for N2, indicating stronger host–guest interactions. The CHF3/N2 selectivity calculated by IAST is 50.1. Dispersion-corrected density functional theory calculations further reveal that CHF3 interacts with the framework through multiple C–F···H and C–H···O contacts. Dynamic breakthrough testing verifies the remarkable separation efficiency of Al-Fum, making it a promising adsorbent for separating CHF3 from N2 mixtures.