HR: 10:50h
AN: U52B-02    [Abstracts]
TI: Testing for Discrete vs. Agglomerated Nanoparticles of 'Iron Oxides'
AU: * Penn, R L
EM: penn@chem.umn.edu
AF: University of Minnesota, Department of Chemistry, 207 Pleasant St. S.E., Minneapolis, MN 55455, United States
AU: Erbs, J J
EM: erbs@chem.umn.edu
AF: University of Minnesota, Department of Geology and Geophysics, 310 Pillsbury Drive S.E., Minneapolis, MN 55455, United States
AU: Jentzsch, T L
EM: jentzsch@chem.umn.edu
AF: University of Minnesota, Institute for Rock Magnetism, 100 Union Street S.E., Minneapolis, MN 55455, United States
AB: Nanoparticles of 'iron oxides' such as ferrihydrite, goethite, hematite and magnetite are found in nature as discrete or agglomerated ('clumped') particles, and with or without dopants such as Al, as and Si. The presence of clumping has important repercussions on both physical and chemical properties of these compounds. We present evidence from a number of nanoparticle systems in which dc and ac susceptibility measurements at low temperatures provide a non-destructive way to assess the presence of agglomeration and the roles of the dopants in modifying such behavior. In addition, we use quantitative kinetics for Fe (III) reduction or Fe(II) oxidation by quinones as our main chemical tool for sample aliquots.
DE: 1030 Geochemical cycles (0330)
DE: 1042 Mineral and crystal chemistry (3620)
DE: 1512 Environmental magnetism
DE: 1527 Paleomagnetism applied to geologic processes
SC: Union [U]
MN: 2007 Joint Assembly