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

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.