Chalcogenide Aerogels as Sorbents for Noble Gases (Xe, Kr)

• Published in: ACS applied materials & interfaces Vol. 9; no. 39; pp. 33389 - 33394
• Main Authors: Subrahmanyam, Kota S, Spanopoulos, Ioannis, Chun, Jaehun, Riley, Brian J, Thallapally, Praveen K, Trikalitis, Pantelis N, Kanatzidis, Mercouri G
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 04.10.2017; American Chemical Society (ACS)
• Subjects: aerogels; chalcogenide; INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; nuclear remediation; porous materials; nuclear remediation; porous materials; aerogels; chalcogenide
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.6b15896

High-surface-area molybdenum sulfide (MoS x ) and antimony sulfide (SbS x ) chalcogels were studied for Xe/Kr gas separation. The intrinsic soft Lewis basic character of the chalcogel framework is a unique property among the large family of porous materials and lends itself to a potential new approach toward the selective separation of Xe over Kr. Among these chalcogels, MoS x shows the highest Xe and Kr uptake, reaching 0.69 mmol g–1 (1.05 mmol cm–3) and 0.28 mmol g–1 (0.42 mmol cm–3) respectively, at 273 K and 1 bar. The corresponding isosteric heat of adsorption at zero coverage (Qst 0) is 22.8 and 18.6 kJ mol–1 and both are the highest among the selected chalcogels. The IAST (10:90) Xe/Kr selectivity at 273 K for MoS x is 6.0, whereas for SbS x chalcogels, it varies in the range 2.0–2.8. The higher formal charge of molybdenum, Mo4+, in MoS x versus that of antimony, Sb3+, in SbS x coupled with its larger atomic size could induce higher polarizability in the MoS x framework and therefore higher Xe/Kr selectivity.