Customized Porous Materials for Selective Separation via Confinement Effect
Primary Author: Derek Deming
Faculty Sponsor: Qiang Zhang
Primary College/Unit: Arts and Sciences
Category: Physical and Social Sciences
Metal–organic frameworks (MOFs) have been subject to extensive research in recent years owing to their diverse porous molecular frames and adaptability to targeted applications. MOFs are comprised of inorganic nodes and organic linkers that can be tailored to suit a prodigious scope of applications, such as catalysis, sensing and separations. One of the most important separations is isolating xenon (Xe) from a mixture of xenon and krypton (Kr). Not only is Xe scarce and an important inert gas used in a variety of purposes (i.e., aerospace, electrical, and medical industries), the capture of Xe from gas mixtures embodies one of the most challenging molecular gas separations. In this work, we have designed a series of novel MOFs based on customized “v-shaped” organic linkers with electron donating and/or withdrawing groups to investigate the role of structure and functional groups in the separation of Xe via the “confinement effect”. Computational results suggested that a series of symmetrical diaryl sulfone and dimethyl-4,4’-oxalyldibenzoate linkers provide the most promising selectivity due to their ideal pore size, approximately 5 Å, to immobilize Xe molecules. These MOFs were comprehensively characterized via x-ray diffraction (single crystal and powder x-ray diffraction), nitrogen adsorption isotherm analysis, ultraviolet-visible and Fourier transform infrared spectroscopy. The role of pore size, shape, and functional groups will be extensively explored to help us gain deep insights into the vital factors influencing Xe adsorption. The goal of the project was to design and synthesize ideal materials for the separation of Xe from gas mixtures.