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Ordering, transport and rotational dynamics of adsorbed carbon dioxide in metal-organic framework Zn2(BDC)2(DABCO)
Peksa, Mikuláš ; Lang, Jan (advisor) ; Bulánek, Roman (referee) ; Dračínský, Martin (referee)
The work analyzes the dynamics of carbon dioxide adsorbed in crystals of anisotropic metalo-organic frameworks Zn2(BDC)2(DABCO). It utilizes nuclear magnetic resonance methods, namely, the 13 C spetroscopy, the PFG method and the measurement of longitudinal relaxation times. Experimental data are compared with calculation of molecular dynamics. The thesis provides a theoretical model for explaining the temperature dependence of the residual anisotropy of the chemical shift observed in the spectra. The method of measuring diffusion anistropy based on the change of the shape of the 13 C spectra is described. The work determines the theoretical course of dependence of the longitudinal relaxation time on temperature using Redfield's theory. Times characterizing dynamic processes running on a picosecond scale that determine the dynamics of the fluid as a whole are evaluated from the data. 2
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Investigation of matter transport in porous materials by means of PFG NMR
Peksa, Mikuláš ; Lang, Jan (advisor) ; Hof, Martin (referee)
Title: Investigation of matter transport by means of PFG NMR Author: Mikuláš Peksa Department of low temperature physics Supervisor: doc. RNDr. Jan Lang, Ph.D. Assistant Supervisor: RNDr. Milan Kočiřík, CSc. (ÚFCH JH AV ČR) Abstract: Estimation of transport-structural parameters such as porosity, tortuosity and surface-to-volume ratio of pores in beds of glass beads is the main goal of this study. These parameters were estimated for 5 samples with different distributions of sizes. The second goal is to probe a possibility to use the same approach to describe the self-diffusion in water solution of LiCl confined in two porous materials based on Al2O3 and glass, respectively. The last goal is the measurement of self-diffusion of water molecules in mesoporous geopolymeric material. Its capability of water transport at long scales have been documented. The measurements of apparent self-diffusion coefficients by means of NMR spectroscopy with pulsed field gradients was major methodology of this work. Keywords: porous material, porosity, tortuosity, self-diffusion, NMR
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