Open AccessNovel Zeolitic Imidazolate Framework/Polymer Membranes for Hydrogen Separations in Coal Processing
Author(s) -
Inga H. Musselman
Publication year - 2013
Language(s) - English
Resource type - Reports
DOI - 10.2172/1091874
Subject(s) - membrane , selectivity , zeolitic imidazolate framework , polymer , imidazolate , chemical engineering , chemistry , stoichiometry , ethylenediamine , polymer chemistry , materials science , analytical chemistry (journal) , inorganic chemistry , adsorption , chromatography , organic chemistry , metal organic framework , catalysis , biochemistry , engineering
Nanoparticles of zeolitic imidazolate frameworks and other related hybrid materials were prepared by modifying published synthesis procedures by introducing bases, changing stoichiometric ratios, or adjusting reaction conditions. These materials were stable at temperatures >300 °C and were compatible with the polymer matrices used to prepare mixed-matrix membranes (MMMs). MMMs tested at 300 °C exhibited a >30 fold increase in permeability, compared to those measured at 35 °C, while maintaining H{sub 2}/CO{sub 2} selectivity. Measurements at high pressure (up to 30 atm) and high temperature (up to 300 °C) resulted in an increase in gas flux across the membrane with retention of selectivity. No variations in permeability were observed at high pressures at either 35 or 300 °C. CO{sub 2}-induced plasticization was not observed for Matrimid®, VTEC, and PBI polymers or their MMMs at 30 atm and 300 °C. Membrane surface modification by cross-linking with ethylenediamine resulted in an increase in H{sub 2}/CO{sub 2} selectivity at 35 °C. Spectrometric analysis showed that the cross-linking was effective to temperatures <150 °C. At higher temperatures, the cross-linked membranes exhibit a H2/CO2 selectivity similar to the uncrosslinked polymer