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| Registros recuperados : 69 | |
| 20. |  | NAKANO, O.; ALVES, J. E. M.; PEREZ, C. A. Perspectiva para o controle da saúva, Atta sexdens rubropilosa, Forel, 1908 (Hymenoptera - Formicidae) com formicidas à base de cobre. Silvicultura, São Paulo, v. 10, n. 39, p. 30-31, 1985.| Biblioteca(s): Embrapa Florestas. |
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| Registros recuperados : 69 | |
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 | Acesso ao texto completo restrito à biblioteca da Embrapa Solos. Para informações adicionais entre em contato com cnps.biblioteca@embrapa.br. |
Registro Completo
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Biblioteca(s): |
Embrapa Solos. |
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Data corrente: |
19/10/2021 |
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Data da última atualização: |
19/10/2021 |
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Tipo da produção científica: |
Artigo em Periódico Indexado |
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Autoria: |
MAVROPOULOS, E.; ROSSI, A. M.; COSTA, A. M.; PEREZ, C. A. C.; MOREIRA, J. C.; SALDANHA, M. F. C. |
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Afiliação: |
ELENA MAVROPOULOS, CBPF; ALEXANDRE MALTA ROSSI, CBPF; ANDRÉA M. COSTA, CBPF; CARLOS ANDRÉ C. PEREZ, NUCAT; JOSINO C. MOREIRA, FIOCRUZ; MARCELO FRANCISCO COSTA SALDANHA, CNPS. |
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Título: |
Studies on the mechanisms of lead immobilization by hydroxyapatite. |
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Ano de publicação: |
2002 |
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Fonte/Imprenta: |
Environmental Science and Technology, v. 36, n. 7, p. 1625-1629, 2002. |
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DOI: |
https://doi.org/10.1021/es0155938 |
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Idioma: |
Inglês |
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Notas: |
Na publicação: Marcelo Saldanha. |
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Conteúdo: |
The sorption of lead by synthetic hydroxyapatite (HA) from solutions containing Pb2+ initial concentrations up to 1770 mg L-1 was studied. X-ray diffractometry (XRD) associated with Rietveld methodology for refining the spectra pattern was used in order to characterize the mechanisms of lead uptake. It is shown that the dissolution of hydroxyapatite is followed by the formation of a solid solution, Pb(10-x)Cax(PO4)6(OH)2, with Pb ions mostly occupying Ca(II) sites. The Ca/Pb molar ratio of this solid solution decreases continuously until it reaches the structure of a pure hydroxypyromorphite. The cell parameters and the crystallite mean size behavior of both mineral phases reinforce the hypothesis that hydroxypyromorphite, PbHA, formation is the end of a process in which Pb(10-x)Cax(PO4)6(OH)2 crystallites are continuously dissolved and recrystallized producing crystals with lower calcium content. Combination of Inductively Coupled Plasma spectrometry (ICP), chemical analysis, and XRD results permitted the conclusion that lead ions are not completely immobilized by precipitating Pb(10-x)Cax(PO4)6(OH)2. Additional surface mechanisms also contribute to Pb2+ uptake. During Pb2+ sorption process, pH variations of the solution phase showed a more complex pattern than previously reported. Contribution of surface mechanisms, in addition to the hydroxyapatite dissolution, could explain this behavior. |
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Palavras-Chave: |
Dissolution; Physical and chemical processes. |
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Thesaurus NAL: |
Hydroxyapatite; Metals; Sorption. |
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Categoria do assunto: |
P Recursos Naturais, Ciências Ambientais e da Terra |
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Marc: |
LEADER 02218naa a2200265 a 4500
001 2135443
005 2021-10-19
008 2002 bl uuuu u00u1 u #d
024 7 $ahttps://doi.org/10.1021/es0155938$2DOI
100 1 $aMAVROPOULOS, E.
245 $aStudies on the mechanisms of lead immobilization by hydroxyapatite.$h[electronic resource]
260 $c2002
500 $aNa publicação: Marcelo Saldanha.
520 $aThe sorption of lead by synthetic hydroxyapatite (HA) from solutions containing Pb2+ initial concentrations up to 1770 mg L-1 was studied. X-ray diffractometry (XRD) associated with Rietveld methodology for refining the spectra pattern was used in order to characterize the mechanisms of lead uptake. It is shown that the dissolution of hydroxyapatite is followed by the formation of a solid solution, Pb(10-x)Cax(PO4)6(OH)2, with Pb ions mostly occupying Ca(II) sites. The Ca/Pb molar ratio of this solid solution decreases continuously until it reaches the structure of a pure hydroxypyromorphite. The cell parameters and the crystallite mean size behavior of both mineral phases reinforce the hypothesis that hydroxypyromorphite, PbHA, formation is the end of a process in which Pb(10-x)Cax(PO4)6(OH)2 crystallites are continuously dissolved and recrystallized producing crystals with lower calcium content. Combination of Inductively Coupled Plasma spectrometry (ICP), chemical analysis, and XRD results permitted the conclusion that lead ions are not completely immobilized by precipitating Pb(10-x)Cax(PO4)6(OH)2. Additional surface mechanisms also contribute to Pb2+ uptake. During Pb2+ sorption process, pH variations of the solution phase showed a more complex pattern than previously reported. Contribution of surface mechanisms, in addition to the hydroxyapatite dissolution, could explain this behavior.
650 $aHydroxyapatite
650 $aMetals
650 $aSorption
653 $aDissolution
653 $aPhysical and chemical processes
700 1 $aROSSI, A. M.
700 1 $aCOSTA, A. M.
700 1 $aPEREZ, C. A. C.
700 1 $aMOREIRA, J. C.
700 1 $aSALDANHA, M. F. C.
773 $tEnvironmental Science and Technology$gv. 36, n. 7, p. 1625-1629, 2002.
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