D.Sc. / The ion exchange properties of a number of synthetic inorganic ion exchangers and the natural zeolite, clinoptilolite, were evaluated with respect to the elements Na, Cs, Sr, Ba, Ce(III), Eu, Zr, U(VI), Np(V), PU(IV) and Am(III). The role of the structure of crystalline exchangers in determining the selectivity thereof, especially in the case of clinoptilolite, was also investigated. Hydrated antimony pentoxide and antimonic acid showed high sorption of a number of ions over a wide pH range (2 - 10). The selectivity order of hydrous oxides for the actinides was as follows: PU(IV) > Am(III) > U(VI) > Np(V). Titanium phosphate, zirconium phosphosilicate and sodium titanate, however, preferred U to Am. To predict the selectivity order of crystalline inorganic ion exchangers, the Eisenman theory could be used, but other factors such as ion sieve effects had to be taken into account. In such cases the parameters contributing to the change in free energy during ion exchange plays a major role. Samples containing clinootilolite from two deposits in South Africa were evaluated with respect to chemical composition, conversion to the sodium, calcium and cesium forms, as well as the sorption of Cs and Sr from various media. Similar trends to those:reported for clinoptilolite from other parts of the world were found. Rietveld refinement of the structure of Cs-exchanged clinoptilolite was carried out using powder diffraction data and the computer program WYRIET. The zeolite was not isolated from the natural matrix, which meant that a number of phases had to be included in the refinement process. The refinement confirmed the...

Thesis (Ph. D.)--Lehigh University, 1999. / Includes vita. Bibliography: leaves 243-258.

Thesis (Ph. D., Chemical Engineering)--University of Idaho, May 2006. / Major professor: Vivek Utgikar. Includes bibliographical references (leaves 99-107). Also available online (PDF file) by subscription or by purchasing the individual file.

Shale oil is an attractive, alternative fuel source for a world in which there is an increasing demand for energy. However, it is necessary to assess the environmental impacts of the shale oil industry before widescale production is begun. Diversity of retorting processes, the subsequent variability in waste products and the possible waste management schemes makes assessment of these impacts complicated. Waste treatment and disposal are areas which must be researched thoroughly. To properly evaluate the environmental risks associated with the disposal of processed shales and process wastewaters, an appreciation for the sorption/desorption (S/D) characteristics of oil shales is required. The overall objective of this research was to evaluate the S/D capacity of four types of shale: Antrim (spent, eastern shale), Anvil (raw, western shale), Oxy 6 and Run 16 (spent, western shales). Batch and continuous-flow, column experiments were performed in which the S/D behavior of five cations (As, Ca, Cd, Fe, and K) and three anions (F, SO₄, and HCO₃/CO₃) was monitored. The conductivity, redox potential, and pH of the eluent fluids were also determined. This study showed that retort temperature and porosity of the various shales had a significant effect an their S/D characteristics. Batch elution trials with spent shales produced eluents having a characteristic pH in the range 8.5 to 11.5. In these experiments, the shales retorted at lower temperatures (660°C and 793°C) released higher levels of Ca, K, and SO₄ than did a higher temperature, retorted shale (800 to 1000°C) and raw shale. The shales retorted at lower temperatures also had the highest porosities of the four shales and exhibited a greater capacity for sorption of As and F than did the other shales. Continuous-flow, elution trials showed that most inorganics monitored were flushed from the columns of shale in the first 5 to 8 pore volumes of effluent. / Master of Science