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dc.contributor.advisorHoldener, Bernadette C.en_US
dc.contributor.authorLi, Weien_US
dc.contributor.otherDepartment of Geosciencesen_US
dc.date.accessioned2012-05-15T18:04:53Z
dc.date.available2012-05-15T18:04:53Z
dc.date.issued1-Dec-10en_US
dc.date.submittedDec-10en_US
dc.identifierLi_grad.sunysb_0771E_10350.pdfen_US
dc.identifier.urihttp://hdl.handle.net/1951/55524
dc.description.abstractPhosphorus is an essential nutrient for plant growth and agriculture. In aqueous environments, interaction of dissolved phosphate with the surfaces of Al oxyhydroxides and clays is important for controlling its transport, fate and bioavailability. Understanding the reaction mechanisms responsible for phosphate uptake at the molecular level can provide significant insight and improved prediction of phosphate uptake behavior, leading to better strategies for phosphate fertilizationand regulation. In this research, I examined the specific adsorption of phosphate on boehmite (&#947;-AlOOH) and other Al (hydr)oxides by combining mainly batch sorption techniques, <super>31</super>P solid-state NMR spectroscopy, quantum chemical calculations and Fouriertransform infrared (FTIR) spectroscopy. Solid state NMR spectroscopy is sensitive with phosphate species that adsorb on mineral surfaces, such that outer-sphere complexes, inner-sphere complexes and surface precipitates can be distinguished.Using novel solid state NMR techniques, such as <super>31</super>P{<super>1</super>H} cross-polarization magic-angle-spinning (CP/MAS) and <super>31</super>P{<super>27</super>Al} dephasing curves from rotational echo adiabatic passage double resonance (REAPDOR) experiments, formation of bridging bidentate or monodentate mononuclear surface complexes can be readily determined. In particular, solid state NMR results indicate that bridging bidentate surface complexes is responsible for the dominant uptake mechanism for all Al-oxyhydroxides under all conditions (0.1. 10 mM P; pH 4-10, etc.). Furthermore, two distinct bidentate surface complexes are resolved for adsorbed phosphate on boehmite, even though macroscopic adsorption isotherm is well fitted by a single-siteLangmuir isotherm. The two species exhibit distinct pH-dependence and different protonation states, and further examination of their reaction stoichiometry suggests they might adsorb at different surface sites. In addition, I found that in the presence of dissolved calcium, the mechanism of phosphate uptake is dominant by surfaceprecipitation of calcium phosphates (Ca-P). The Ca-P surface precipitate is identified as poorly crystalline hydroxylapatite by two-dimensional <super>31</super>P{<super>1</super>H} heteronuclear correlation (HetCor) experiments. To summarize, this dissertation shows <super>31</super>P solid state NMR is significant sensitivity to the chemical environment and motional property of phosphate adsorbed on different Al (hydr)oxides, from which a better understanding of mineral surfaces can be achieved by using <super>31</super>P nuclei as a molecular probe.en_US
dc.description.sponsorshipStony Brook University Libraries. SBU Graduate School in Department of Geosciences. Lawrence Martin (Dean of Graduate School).en_US
dc.formatElectronic Resourceen_US
dc.language.isoen_USen_US
dc.publisherThe Graduate School, Stony Brook University: Stony Brook, NY.en_US
dc.subject.lcshGeochemistry -- Environmental Sciences -- Physical Chemistryen_US
dc.subject.otheradsorption, aluminum (hydr)oxide, phosphate, solid state NMRen_US
dc.titleMultinuclear Solid-State NMR Studies of Phosphate Uptake by Aluminum (Hydr)oxidesen_US
dc.typeDissertationen_US
dc.description.advisorAdvisor(s): Brian L. Phillips. Richard J. Reeder. Committee Member(s): Martin A. Schoonen; Michael Sperazza; R James. Kirkpatrick.en_US
dc.mimetypeApplication/PDFen_US


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