A Study of the Adsorption of Ni(II) and Cu(II) by Clay Minerals

Self Cite

Abstract--The nature of Cr(NH3)63+ and Cr(en)33+ (en = ethylenediamine) adsorbed on chlorite, illite, and kaolinite has been studied by X-ray photoelectron spectroscopy (XPS). The interaction of the chromium complexes with the clays began at pH 3. During the 7-day interaction time the pH of the complex-clay suspension increased to 8 for illite and chlorite. For kaolinite the pH increased to about 3.6 with Cr(NH3)63+ and to 6.4 with Cr(en)33+. These pH changes appear to be associated with a clay-catalyzed hydrolysis of the chromium-amine complexes. XPS binding-energy data for adsorbed chromium indicate that the dominant species are chromium aqua complexes. Nitrogen/chromium atom ratios, calculated from the XPS photopeak intensities, are less than 6: l for complexes adsorbed on the clays, suggesting that chromium complexes are initially adsorbed but subsequently hydrolyze to produce aqua-chromium surface species.

Section: Xps Measurementssupporting

confidence: 92%

“…The identity and characteristics of the clays studied were described by Koppelman and Dillard (1977) and are briefly summarized here. Chlorite from Ishpeming, Michigan, was obtained from Ward's Natural Science Establishment and has a cation-exchange capacity (CEC) of 16 meq/100 g and a N2-BET surface area of 14 m2/g.…”

Section: Methodsmentioning

confidence: 99%

Adsorption of Cr(NH₃)₆³⁺ and Cr(en)₃³⁺ on Clay Minerals and the Characterization of Chromium by X-Ray Photoelectron Spectroscopy

Koppelman

Dillard

1980

Self Cite

“…Koppelman and Dillard (1977) mentioned the reduction of Cu(II) adsorbed on chlorite by the photoreduction effect; this effect increased with exposure time to the X-ray beam. This phenomenon was also observed in other Cu(II) systems by Rosencwaig et al (1971), Frost et al (1972), and Wallbank et al (1973).…”

Section: Photoreduction Effectmentioning

confidence: 99%

Natural and Synthetic Copper Phyllosilicates Studied by XPS

Mosser

Roméo

et al. 1992

Abstract--X-ray photoelectron spectroscopy (XPS) has been used to characterize the bonding state of Cu 2 § Si 4+, A13 § and 02 ions in structural (octahedral and interlamellar) or adsorbed position in phyllosilicates. Five smectites, 5 kaolinites, and 1 chrysocolla with Cu(II) in known positions (octahedral, interlamellar, or surface adsorbed) have been investigated. Their spectra were compared with those of pure Cu metal and of pure Cu(I) and Cu(II) oxides.The line for Cu 2p3/2 (binding energy of 935.4 eV) and well-defined shake-up lines (binding energy of about 943 eV) observed after 1 hr of X-ray irradiation are characteristic of Cu(II) in phyllosilicate octahedral sites. But due to the photoreduction effect, they show Cu(I) oxidation states (Cu 2P3/2, binding energy of 933.2 eV and near absence of shake-up lines) for the phyllosilicates with adsorbed Cu or in interlamellar positions. The kinetics of photoreduction distinguishes octahedral from interlamellar positions, and the latter from a surface adsorbed position. The enlargement of the FWHM (full width at half maximum) of XPS lines has been used to describe crystallochemical parameters linked to local ordering around the probe cations. Crystallization produces decreasing O 1 s and Cu 2p (octahedral cation) line widths but has no effect on the Si 2p (tetrahedral cation) line width. The enlargement of FWHM for all ion lines of the lattice is linked to the nature (Cu > Mg > AI) and the number and amount of structural cations in the phyllosilicates.

“…Si makes up most of the tetrahedral layer (Si/A1 -6.8), and AI, Fe, and Mg are primary constituents of the octahedral layer. All Fe was arbitrarily considered as Fe a § Other trace elements (Table 2), such as Cu, Zn, Co, Mn, Pb, Ni, Cd, and Cr, can be structurally bound in octahedral coordination or can be present as exchangeable cations in clays (Counts et al, 1973;Pronina and Varentsov, 1973;McBride, 1976;Koppelman and Dillard, 1977). The exchangeable cations, however, are mainly Na, with some K and Ca (Table 3).…”

Section: Smectite Chemistry and Mineralogymentioning

confidence: 99%

Origin of Iron-Rich Montmorillonite from the Manganese Nodule Belt of the North Equatorial Pacific

Hein

Yeh

Alexander

1979

108

Abstract--Clay minerals in the upper 50 cm of sediment that surround the Cu-and Ni-rich manganese nodules in the North Equatorial Pacific form two fractions: terrigenous (mostly eolian) illite, chlorite, and kaolinite, and authigenic smectite. Smectite increases with depth in box cores from 26 to 39% and from 53 to 66% in the easternmost and westernmost areas respectively, and with distance seaward from the Americas from 26 to 53% in surface deposits. The change in the amount of smectite relative to other clay minerals is due to dilution by terrigenous debris; smectite probably forms at a uniform rate over much of the North Pacific deep-sea floor. The 6018 value for the smectite is +29.6%0 which suggests that it formed authigenically at a temperature characteristic of the deep-sea floor. The smectite is an Fe-rich montmorillonite that probably forms by the low-temperature chemical combination of Fe hydroxides and silica. Silica is derived from dissolution of biogenic debris, and the Fe hydroxide is from volcanic activity at the East Pacific Rise, 4000 to 5000 km to the east. AI in the authigenic montmorillonite may be derived from the dissolution of large amounts of biogenic silica or from river-derived A1 that is adsorbed on Fe-Mn hydroxides in the oceans. The Fe-montmorillonite contains relatively abundant Cu, Zn, and Mn and is of possible economic importance as a source of these and other metals.