| Autor: |
Mullangi D; Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575 Singapore., Evans HA; Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States., Yildirim T; Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States., Wang Y; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 Singapore., Deng Z; Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575 Singapore., Zhang Z; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 Singapore., Mai TT; Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States., Wei F; Institute of Materials Research and Engineering, Agency for Science Technology and Research, 2 Fusionopolis Way, Innovis, 138634 Singapore., Wang J; Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575 Singapore., Hight Walker AR; Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States., Brown CM; Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States.; Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States., Zhao D; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 Singapore., Canepa P; Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575 Singapore.; Department of Chemical and Biomolecular Engineering, National University of Singapore, 4 Engineering Drive 4, 117585 Singapore., Cheetham AK; Department of Materials Science and Engineering, National University of Singapore, 9 Engineering Drive 1, 117575 Singapore.; Materials Research Laboratory, University of California, Santa Barbara, Santa Barbara, California 93106, United States. |
| Abstrakt: |
Separating oxygen from air to create oxygen-enriched gas streams is a process that is significant in both industrial and medical fields. However, the prominent technologies for creating oxygen-enriched gas streams are both energy and infrastructure intensive as they use cryogenic temperatures or materials that adsorb N 2 from air. The latter method is less efficient than the methods that adsorb O 2 directly. Herein, we show, via a combination of gas adsorption isotherms, gas breakthrough experiments, neutron and synchrotron X-ray powder diffraction, Raman spectroscopy, and computational studies, that the metal-organic framework, Al(HCOO) 3 (ALF), which is easily prepared at low cost from commodity chemicals, exhibits substantial O 2 adsorption and excellent time-dependent O 2 /N 2 selectivity in a range of 50-125 near dry ice/solvent (≈190 K) temperatures. The effective O 2 adsorption with ALF at ≈190 K and ≈0.21 bar (the partial pressure of O 2 in air) is ≈1.7 mmol/g, and at ice/salt temperatures (≈250 K), it is ≈0.3 mmol/g. Though the kinetics for full adsorption of O 2 near 190 K are slower than at temperatures nearer 250 K, the kinetics for initial O 2 adsorption are fast, suggesting that O 2 separation using ALF with rapid temperature swings at ambient pressures is a potentially viable choice for low-cost air separation applications. We also present synthetic strategies for improving the kinetics of this family of compounds, namely, via Al/Fe solid solutions. To the best of our knowledge, ALF has the highest O 2 /N 2 sorption selectivity among MOF adsorbents without open metal sites as verified by co-adsorption experiments.. |
