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| Batista,Marcelo Augusto; Costa,Antonio Carlos Saraiva da; Souza Junior,Ivan Granemann de; Bigham,Jerry Marshal. |
| Maghemite (g-Fe2O3) is the most usually found ferrimagnetic oxide in red basalt-derived soils. The variable degrees of ionic substitution of Fe3+ for different metals (e.g. Ti4+, Al3+, Mg2+, Zn2+, and Mn2+) and non-metals in the maghemite structure influence some cristallochemical features of this iron oxide. In this study, synthetic Zn-substituted maghemites were prepared by co-precipitation in alkaline aqueous media of FeSO4.7H2O with increasing amounts of ZnSO4.7H2O to obtain the following sequence of Fe3+ for Zn2+ substitutions: 0.0, 0.025, 0.05, 0.10, 0.15, 0.20, and 0.30 mol mol-1. The objective of this work was to evaluate the cristallochemical alterations of synthetic Zn-substituted maghemites. The dark black synthetic precipitated material was... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Iron oxides; X ray diffraction; Mass-specific magnetic susceptibility; Specific surface area; Isomorphic substitution. |
| Ano: 2008 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-06832008000200011 |
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| Silva Neto,Luís de França da; Inda,Alberto Vasconcellos; Nascimento,Paulo César Do; Giasson,Elvio; Schmitt,Catiline; Curi,Nilton. |
| ABSTRACTIn the Porto Alegre metropolitan region (PAMR) there are a significant proportion of floodplain soils, mainly Planosols and Gleysols, in relation to upland soils. This study aimed to evaluate the morphological, chemical and physical characteristics, and to classify floodplain soils in the PAMR. Six soil profiles were evaluated under different sedimentary lithologies and drainage classes, and samples were collected for chemical and physical analyzes. Two orders of mineral soils (Planosols and Gleysols) and one order of organic soil (Organosols) were identified. The soils were moderately deep to deep and stratified. In mineral soils hue ranged between 7.5YR and 2.5Y, with the occurrence of Bg, Btg or Cg gley horizons, while in organic soil the colors... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Hydromorphic soils; Quaternary sediments; Specific surface area. |
| Ano: 2015 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542015000500423 |
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