Solid Porous Materials for Selective Capture and Separation of Sulfur Hexafluoride (SF6).

Developing technologies to capture, purify, and reuse potent greenhouse gases such as sulfur hexafluoride (SF₆) is crucial because of their high global warming potential. Porous solid matrices are promising candidates for this purpose, due to their high surface areas and pore volumes. Herein, two coconut shell-derived activated carbons (AC) (CS-CO₂ and CS-ZnCl₂), obtained through physical and chemical activation, are evaluated and compared with two commercial adsorbents: an AC monolith (ACM) and a metal-organic framework. The adsorption capacities for SF₆ and nitrogen (N₂) are measured gravimetrically at three temperatures: 283.15, 303.15, and 323.15 K. The experimental data are fitted using the Toth model, and the impact of temperature and pressure on the adsorption performance is analyzed. The order of SF₆ adsorption capacity is: ACM > CS-ZnCl₂ > Fe-BTC > CS-CO₂, reflecting dependence on surface area. Selectivity for SF₆/N₂ separation is evaluated using Ideal Adsorbed Solution Theory, with ACM exhibiting the highest adsorption capacity due to its selective separation properties. These findings contribute to the understanding and selection of efficient adsorbent materials for SF₆ separation and recovery, providing valuable insights for their future implementation in industrial gas treatment and environmental management applications.