Date of Graduation

Fall 2020

Degree

Master of Science in Materials Science

Department

Physics, Astronomy, and Materials Science

Committee Chair

Robert Mayanovic

Keywords

uranium, thorium, hydrothermal diamond anvil cell, Raman spectroscopy, hydrothermal conditions, speciation distribution

Subject Categories

Geochemistry | Other Materials Science and Engineering

Abstract

Raman spectra were acquired for a uranyl chloride aqueous solution at temperatures ranging from 25°C to 500°C at the chloride concentration of 6M and uranium (vi) concentration of 0.05M. The measurements were taken by sealing the sample in a hydrothermal diamond anvil cell (HDAC) which enabled spectra acquisition at non-ambient conditions. The pressure inside the cell was measured by estimating the liquid-vapor homogenization temperature (TH) and using the isochoric equation of state diagram of water. The acquired spectra were then fitted to determine the speciation distribution of the various uranyl chloride species for the mentioned concentration. The developed speciation distribution profile was then combined with the speciation distribution profiles of lower concentrations of 0.2M, 1M and 3M to get a complete picture of the aqueous uranyl chloride system’s speciation distribution. Similar experiments were carried out for aqueous thorium (iv) chloride solutions at high P-T conditions. Three solutions with chloride concentrations of approximately 0.1M, 1.1M and 3.1M were prepared. Raman spectra were acquired for each of these samples in the temperature range of 25°C to 500°C by sealing them in the HDAC. The pressure was estimated in a similar manner that was made for the uranyl chloride system. The acquired spectra were fitted using very similar procedures and the speciation distribution for the system was determined.

Copyright

© Nadib Akram

Available for download on Friday, December 01, 2023

Open Access

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