.

The mechanisms of uranium removal from water by iron oxyhydroxides, nanocrystalline titanium dioxide, and elemental iron

LAUR Repository

Show simple item record

dc.contributor.author Wazne, Mahmoud
dc.date.accessioned 2018-09-17T06:03:58Z
dc.date.available 2018-09-17T06:03:58Z
dc.date.copyright 2003 en_US
dc.date.issued 2018-09-17
dc.identifier.uri http://hdl.handle.net/10725/8467
dc.description.abstract The removal mechanisms and efficiencies of uranium from water by iron oxyhydroxides, nanocrystalline titanium dioxide, and elemental iron were investigated in artificial and natural systems. Batch tests, zeta potential measurements, and Fourier Transform Infrared (FTIR) spectroscopic studies were utilized to characterize the nature of hexavalent uranium [U(VI)] adsorption on ferrihydrite and nanocrystalline titanium dioxide. Adsorption isotherms demonstrated that carbonate had a negative effect on U(VI) adsorption on ferrihydrite at pH > 6. Zeta potential measurements indicated that U(VI) was adsorbed on ferrihydrite as a cationic species (SO-UO2+) in the absence of carbonate and as anionic U(VI) complexes in the presence of carbonate at neutral pH. FTIR spectroscopic measurement of adsorbed U(VI) on ferrihydrite suggested that it was retained as uranyl carbonate complexes in the presence of carbonate. An increase in carbonate concentration caused a shift in the antisymmetric stretching vibration of the uranyl (UO2 2+) U-O bond toward lower wavenumbers, which indicated an increasing carbonate effect in the adsorbed uranyl carbonate complexes. Adsorption isotherms indicated that carbonate also had negative effect on U(VI) adsorption on titanium dioxide at pH > 6.0. Zeta potential and FTIR studies indicated that U(VI) was adsorbed on titanium dioxide as a cationic species in the presence and absence of carbonate. An increase in carbonate concentration caused a shift in the chemical equilibrium in favor of aqueous uranyl carbonate complexes. The adsorbed U(VI) species were successfully incorporated into a surface complexation model to describe the adsorption of U(VI) by ferrihydrite and titanium dioxide from artificial solutions and contaminated water. Batch tests indicated that U(VI) was reduced to tetravalent uranium [U(IV)] by elemental iron under anaerobic conditions. Evidence suggested that U(VI) reduction by elemental iron was catalyzed by the iron surface. Even though the reaction was thermodynamically feasible, U(VI) was not reduced by ferrous iron in a homogenous solution under anaerobic conditions at pH > 7.0. In the presence of dissolved oxygen, uranium was removed from water by ferrous and elemental iron through U(VI) adsorption onto iron hydroxides. A better description of the adsorbed uranium surface species was achieved through the use of batch tests, Zeta potential and FTIR spectroscopic experiments. These results were used to predict the mobility of uranium in natural environments and the removal efficiencies of uranium by iron oxyhydroxides, nanocrystalline titanium dioxide, and elemental iron. The knowledge gained was successfully used to remediate depleted uranium contaminated water at a Department of Defense site. en_US
dc.language.iso en en_US
dc.title The mechanisms of uranium removal from water by iron oxyhydroxides, nanocrystalline titanium dioxide, and elemental iron en_US
dc.type Thesis en_US
dc.author.degree PHD en_US
dc.author.school SOE en_US
dc.author.idnumber 201205627 en_US
dc.author.department Civil Engineering en_US
dc.description.embargo N/A en_US
dc.description.physdesc 174 p. en_US
dc.keywords Engineering en_US
dc.keywords Environmental en_US
dc.keywords Environmental sciences en_US
dc.keywords Geochemistry en_US
dc.description.bibliographiccitations Includes bibliographical references en_US
dc.identifier.ctation Wazne, M. (2004). The mechanisms of uranium removal from water by iron oxyhydroxides, nanocrystalline titanium dioxide, and elemental iron. en_US
dc.author.email mahmoud.wazne@lau.edu.lb en_US
dc.identifier.tou http://libraries.lau.edu.lb/research/laur/terms-of-use/thesis.php en_US
dc.identifier.url https://elibrary.ru/item.asp?id=5970615 en_US
dc.publisher.institution Stevens Institute of Technology en_US
dc.author.affiliation Lebanese American University en_US


Files in this item

Files Size Format View

There are no files associated with this item.

This item appears in the following Collection(s)

Show simple item record

Search LAUR


Advanced Search

Browse

My Account