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| Silva,Sérgio Henrique Godinho; Silva,Elen Alvarenga; Poggere,Giovana Clarice; Guilherme,Luiz Roberto Guimarães; Curi,Nilton. |
| ABSTRACT Portable X-ray fluorescence spectrometer (pXRF) has been recently adopted by the Soil Science community for uses in both field and laboratory, obtaining the total content of several chemical elements in a few seconds. Sulfuric acid digestion is an expensive and time-consuming laboratory analysis that provides contents of Fe2O3, Al2O3, SiO2, TiO2 and P2O5, important for soil studies. Due to few pXRF studies in tropical soils, this work aimed to compare contents of Fe2O3, Al2O3, SiO2, TiO2 and P2O5 obtained by pXRF with sulfuric acid digestion results, and to evaluate the effects of varying forms of preparing soil samples and scanning with pXRF on the resulting values in Brazilian soils. Soils were scanned in five conditions in-field (in situ) and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Soil chemical properties; Proximal sensor; Sulfuric acid digestion analysis; Soil properties prediction; Oxides. |
| Ano: 2018 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542018000100080 |
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| CORREIA, F. H.; CURADO, I. C.; GHESTI, G. F.; BRAGA, P. R. S.; MARINHO, A. L. A.; MATTOS, L. V.; NORONHA, F. B.; SOARES, I. P.; SCHULTZ, E. L.. |
| Ni-Mg-Al mixed oxides derived from hydrotalcite-like compounds were prepared by a co-precipitation technique, calcined at two temperatures (550 °C and 750 °C) and applied to steam reforming of simulated biogas. Three nickel contents were used in the catalysts (5, 10 and 15%). The catalysts were characterized by X ray fluorescence, N2 sorption techniques, X-ray diffraction and temperature-programmed desorption of CO2. Steam reforming experiments using simulated biogas were carried out at atmospheric pressure and 750 °C, using S/C ratio of 3.2. Catalysts calcined at 750 °C showed nickel and magnesium aluminate phases, resulting in lower density of basic sites. Conversion of CH4 ranged from 97.4 to 99.6% while CO2 conversion ranged from 58.5 to 63.5%. The... |
| Tipo: Folhetos |
Palavras-chave: Steam reforming; Mixed oxides; Biogás; Níquel; Oxido; Steam; Nickel; Catalysts; Oxides. |
| Ano: 2020 |
URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/1124168 |
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| Prata,Fábio; Cardinali,Vanessa Camponez do Brasil; Lavorenti,Arquimedes; Tornisielo,Valdemar Luiz; Regitano,Jussara Borges. |
| The sorption of glyphosate by soils occurs due to the inner sphere complex formation with metals of soil oxides, which are related to the soil phosphate adsorption capacity. The aim of this study was to evaluate the effects of increasing rates of phosphorus on sorption and desorption of glyphosate in three soils with different mineralogical attributes. Soils were a Rhodic Kandiudalf, an Anionic Acrudox and a Typic Humaquept. Soil samples were amended with KH2PO4 at equivalent rates of 0; 1,000; 5,000; 20,000 and 50,000 kg ha-1 of P2O5, which are high from the agricultural point of view, but necessary in order to perform sorption and desorption studies. The experimental design consisted of a completely randomized factorial: 2 soils x 5 phosphorus rates and... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Herbicide; Retention; Bound residue; Phosphate; Oxides. |
| Ano: 2003 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162003000100026 |
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