Oxygen-selective adsorption in RPM3-Zn metal organic framework

Cheng Yu Wang, Linxi Wang, Andrew Belnick, Hao Wang, Jing Li, Angela Lueking

Research output: Contribution to journalArticle

5 Scopus citations

Abstract

Development of an oxygen selective adsorbent is anticipated to reduce the material and energy requirements for adsorptive separations of air by a factor of four, due to the relative concentrations of N2 and O2 in air, thereby decreasing the parasitic energy losses, carbon dioxide emissions, and cost of oxygen purification via pressure-swing adsorption. Here, we report that RPM3-Zn (a.k.a. Zn2(bpdc)2(bpee); bpdc = 4,4′-biphenyldicarboxylate; bpee = 1,2-bipyridylethene) is oxygen selective over nitrogen at temperatures from 77 K to 273 K, although the oxygen capacity of the sorbent decreased markedly at increasing temperatures. Due to an oxygen diffusivity that is ∼1000-fold greater than nitrogen, the effective oxygen selectivity increases to near infinity at low temperature at equal contact times due to N2 mass transfer limitations for gate-opening. The kinetic limitation for N2 to open the structure has a sharp temperature dependence, suggesting this effective kinetic selectivity may be “tuned in” for other flexible metal-organic-frameworks. Although the low temperature oxygen selectivity is not practical to displace cryogenic distillation, the results suggest a new mechanism for tailoring materials for kinetic selectivity, namely, capitalizing upon the delayed opening process for a particular gas relative to another.

Original languageEnglish (US)
Pages (from-to)122-130
Number of pages9
JournalChemical Engineering Science
Volume165
DOIs
StatePublished - Jan 1 2017

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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    Wang, C. Y., Wang, L., Belnick, A., Wang, H., Li, J., & Lueking, A. (2017). Oxygen-selective adsorption in RPM3-Zn metal organic framework. Chemical Engineering Science, 165, 122-130. https://doi.org/10.1016/j.ces.2017.02.020