EPR, FT-IR and XRD investigation of soils from Parana, Brazil
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
20/10/2012
20/10/2012
2011
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Resumo |
Samples of Araucaria area soil from Parana state, Brazil, were separated by particle size fractionation and investigated by electron paramagnetic resonance (EPR) in X-Band of 9.5 GHz at room temperature and 77K, infra-red spectroscopy and X-ray diffractometry. The paramagnetic species in the soil samples were identified by comparison with EPR spectra of some minerals studied recently by our group, several soil types and/or soil components investigated in the literature. The value of g = 2.1 (Delta H = 85 mT) indicated the presence of ferrihydrite. Hematite was identified by g = 2.1 (Delta H = 100 mT) and g = 4.3 for Fe(3+) lines of the concentrated dominium and diluted dominium. Kaolinite was identified by IR and EPR with the resonance at g = 4.3 attributed to Fe(3+) ions in isolated sites of tetrahedral and octahedral symmetry with rhombic distortion. The resonances at g = 3.7 and g = 4.9 were attributed to Fe(3+) in more highly symmetrical environment than rhombic symmetry, but not in axial symmetry. Three signals around g = 2 were attributed to radiation defects, plus additional resonances at g = 2.8 and 9.0. Signals less intense than those at g = 2.1, 3.7, and 6.5, observed for clear grains of soil, were attributed to presence of Fe(3+) in quartz which was identified by IR and XDR. (C) 2011 Elsevier B.V. All rights reserved. Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES-Brazil) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) |
Identificador |
APPLIED CLAY SCIENCE, v.53, n.1, p.42-47, 2011 0169-1317 http://producao.usp.br/handle/BDPI/29225 10.1016/j.clay.2011.04.018 |
Idioma(s) |
eng |
Publicador |
ELSEVIER SCIENCE BV |
Relação |
Applied Clay Science |
Direitos |
restrictedAccess Copyright ELSEVIER SCIENCE BV |
Palavras-Chave | #Fe(3+) #Ferrihydrite #Hematite #Kaolinite #Quartz #ELECTRON-PARAMAGNETIC-RESONANCE #SPIN RESONANCE #NATURAL KAOLINITES #GLASSES #LUMINESCENCE #ABSORPTION #STABILITY #SPECTRA #ORIGIN #FE3 #Mineralogy |
Tipo |
article original article publishedVersion |