Pore structure modulation of chitosan-derived porous carbon materials for enhanced sulfur hexafluoride gas adsorption

Abstract

In the semiconductor industry, the efficient capture and recovery of sulfur hexafluoride (SF₆) from SF₆/N₂ mixtures holds utmost significance. This study designs a series of porous carbon materials derived from chitosan via potassium hydroxide (KOH) activation, tailored for fluorine-containing gases adsorption. Adsorption kinetics, thermodynamics, and dynamic penetration adsorption experiments were conducted to explore the structure–activity relationship between the structure of porous carbon materials and their SF₆ adsorption performance. Among these materials, AC-KOH_(1:1)-800 exhibits the highest SF₆ adsorption capacity of 5.88 mmol·g⁻¹ at 298 K and 1 bar, coupled with an ideal adsorption solution theory (IAST) selectivity for SF₆/N₂(10/90) separation of 126, which surpasses most reported adsorption materials thus far. Furthermore, adsorption–desorption cyclic experiments and penetration tests reveal excellent stability, with minimal decrease in SF₆ separation performance after repeated use. The simplicity of the preparation process, combined with the high adsorption capacity, good selectivity, and stability, renders chitosan-derived porous carbon materials highly promising for practical SF₆ separation applications. This study not only offers novel insights into the design of carbon-based gas adsorption materials but also introduces a potent porous carbon tailored for the selective separation of fluorine-containing gases.