Deep eutectic solvents with multiple hydroxyl sites for efficient and reversible absorption of SF6

Finding the adsorbents to efficiently and reversibly capture SF6 has important research significance. Most of the currently reported solid absorbents used to capture SF6 can have disadvantages such as difficult recovery and easy deactivation. To address this critical challenge, we here report an effective strategy to capture sulfur hexafluoride (SF6) using the hydroxyl-rich deep eutectic solvents (DESs) for the first time. The physical properties of as-prepared seven hydroxyl-rich DESs are systematically investigated, and the effects of structure of DESs, absorption temperature, pressure, and water content on absorption performance of SF6 also are inspected, respectively. In particular, ChCl-Gly (1:2) not only exhibits highest absorption capacity of SF6 with up to 0.1738 g SF6/g DES at 293.2 K and 1.0 bar, but also can be reused without significant decline in absorption capacity of SF6. In addition, the absorption mechanism study of SF6 is conducted by FTIR, NMR and DFT chemical calculations. The results suggest that the high absorption capacity of SF6 originates from the intermolecular hydrogen bonding of SF6 molecules and hydroxyl protons in DESs. (c) 2022 Elsevier B.V. All rights reserved.

Automated summary

This study reports an effective strategy using hydroxyl-rich deep eutectic solvents (DESs) for capturing sulfur hexafluoride (SF6) and investigates the physical properties of different DESs as well as the effects of absorption conditions on SF6 capture performance.