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Type: Artigo de periódico
Title: Soil characterisation using X-ray diffraction, photoacoustic spectroscopy and electron paramagnetic resonance
Author: Manhaes, RST
Auler, LT
Sthel, MS
Alexandre, J
Massunaga, MSO
Carrio, JG
dos Santos, DR
da Silva, EC
Garcia-Quiroz, A
Vargas, H
Abstract: The optical absorption spectra and chemical composition of soil samples were characterised using photoacoustic spectroscopy (PAS), electron paramagnetic resonance (EPR), X-ray diffraction and X-ray fluorescence. From fluorescence results, the chemical components were identified and an Fe mass concentration varying between 4% and 10% was determined. Besides that, the observed photoacoustic technique (PA) spectra showed transition bands associated with Fe3+ ions. From the phase behaviour, both the nonradiative relaxation time tau and the characteristic thermal diffusion time tau(beta) were determined. The X-ray diffraction analysis showed that kaolinite is a major crystalline phase (86% in mass) followed by minor quantities of anatase, gibbsite and quartz. Rietveld refinements showed that the Fe3+ cations partially substitute for Al3+ cations in the octahedral sites of the kaolinite structure. EPR measurements were performed in order to determine the crystalline environment of Fe ions; the observed profiles indicate that Fe sites are embedded in a distorted cubic crystalline field. (C) 2002 Elsevier Science B.V. All rights reserved.
Subject: XRD
thermal properties
Country: Holanda
Editor: Elsevier Science Bv
Rights: fechado
Identifier DOI: 10.1016/S0169-1317(02)00092-3
Date Issue: 2002
Appears in Collections:Artigos e Materiais de Revistas Científicas - Unicamp

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