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Title: Direct Observation of Xe and Kr Adsorption in a Xe-selective Microporous Metal Organic Framework

We found that the cryogenic separation of noble gases is energy-intensive and expensive, especially when low concentrations are involved. Metal–organic frameworks (MOFs) containing polarizing groups within their pore spaces are predicted to be efficient Xe/Kr solid-state adsorbents, but no experimental insights into the nature of the Xe–network interaction are available to date. Here we report a new microporous MOF (designated SBMOF-2) that is selective toward Xe over Kr under ambient conditions, with a Xe/Kr selectivity of about 10 and a Xe capacity of 27.07 wt % at 298 K. Single-crystal diffraction results show that the Xe selectivity may be attributed to the specific geometry of the pores, forming cages built with phenyl rings and enriched with polar -OH groups, both of which serve as strong adsorption sites for polarizable Xe gas. The Xe/Kr separation in SBMOF-2 was investigated with experimental and computational breakthrough methods. These experiments showed that Kr broke through the column first, followed by Xe, which confirmed that SBMOF-2 has a real practical potential for separating Xe from Kr. Our calculations showed that the capacity and adsorption selectivity of SBMOF-2 are comparable to those of the best-performing unmodified MOFs such as NiMOF-74 or Co formate.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [2] ;  [4] ;  [2] ;  [5]
  1. Stony Brook Univ., NY (United States)
  2. Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
  3. Univ. of Amsterdam (Netherlands)
  4. Brookhaven National Lab. (BNL), Upton, NY (United States)
  5. Stony Brook Univ., NY (United States); Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
OSTI Identifier:
1237163
Report Number(s):
BNL--108192-2015-JA
Journal ID: ISSN 0002-7863; R&D Project: LS001
Grant/Contract Number:
SC00112704
Type:
Accepted Manuscript
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 137; Journal Issue: 22; Journal ID: ISSN 0002-7863
Publisher:
American Chemical Society (ACS)
Research Org:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org:
USDOE Office of Science (SC)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE