Oxygen-selective adsorption in RPM3-Zn metal organic framework

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

Research output: Contribution to journalArticle

5 Citations (Scopus)

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
Pages (from-to)122-130
Number of pages9
JournalChemical Engineering Science
Volume165
DOIs
Publication statusPublished - Jan 1 2017

Keywords

  • Air separation
  • Gate opening
  • Kinetic selectivity
  • Metal organic frameworks
  • RPM3-Zn

ASJC Scopus subject areas

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

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