Search results for "mannite"
showing 3 items of 3 documents
La manna delle Madonie(Sicilia): dai frassini ai prodotti farmaceutici e alimentari.
2011
Structure and the metal-support interaction of the Au/Mn oxide catalysts
2010
Gold catalysts with loading 1 and 10 wt % were-prepared by deposition precipitation method with urea over mesoporous manganese oxide, obtained through a surfactant-assisted procedure by using cetyltrimethylammonium bromide (CTAB), followed by treatment with sulphuric acid. For comparison, Au(10 wt %) was also deposited over commercial CeO2 and SiO2 supports. The materials were characterized by XRD and EXAFS at the Mn K and Au L-III edges and XPS. Moreover, the analyses were performed on the samples treated under 1%CO/He, at 250 degrees C for 90 min. The structural and surface results of the as prepared manganese oxide confirmed the formation of gamma-MnO2 along with some amorphous Mn3O4 upo…
Sorption of uranium(VI) onto ferric oxides in sulfate-rich acid waters.
2003
The mechanisms of the uranium(VI) sorption on schwertmannite and goethite in acid sulfate-rich solutions were studied by Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. The samples were prepared under N2 atmosphere and initial uranium(VI) concentrations of 1 x 10(-5) (pH 6.5) to 5 x 10(-5) M (pH 4.2). The ionic strength was adjusted using 0.01 M Na2SO4 or 0.01 M NaClO4, respectively. The EXAFS structural parameters for uranium(VI) sorbed on goethite in sulfate-rich, acid and near-neutral solutions indicate that uranium(VI) forms an inner-sphere, mononuclear, bidentate surface complex. This complex is characterized by a uranium-ferric-iron distance of approximately 3.45 A. Ura…