Adsorption of Co(II) at the oxide-water interface

Tewari, P. H.; Lee, Woon

doi:10.1016/0021-9797(75)90304-5

Cited by 194 publications

(69 citation statements)

References 11 publications

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“…1 and 2) show that the amount of metal adsorbed to the goethite surface at a given pH increases with increasing temperature. This behavior has been noted previously for adsorption of a wide range of heavy metals onto oxide surfaces (11,13,16,17,24,25). Adsorption of Co(II) occurs at a pH at each temperature slightly higher than that of Cd(II), a characteristic of adsorption on goethite observed at 25°C by Spark et al (22) in a study of heavy metal adsorption on various oxide surfaces.…”

Section: Adsorption Edgessupporting

confidence: 77%

The Influence of Temperature on the Adsorption of Cadmium(II) and Cobalt(II) on Goethite

Angove

Wells

Johnson

1999

Journal of Colloid and Interface Science

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The adsorption of Cd(II) and Co(II) onto goethite was measured at five temperatures between 10 and 70 degrees C. For both cations the amount adsorbed at any given pH increased as the temperature was increased. Cd(II) adsorbed at a slightly lower pH at each temperature than Co(II). Adsorption isotherms at pH 7.00 for Cd(II) could be fitted closely by a simple Langmuir model, but a two-site Langmuir model was needed for Co(II). Potentiometric titrations of goethite suspensions in the presence and absence of added cation could be modeled closely by a constant-capacitance surface complexation model that assumed the adsorption reactions M2+ + SOH ⇋ SOM+ + H+ and M2+ + SOH + H2O ⇋ SOMOH + 2H+, where M represents Cd or Co. This model also fitted the experimental data from the adsorption edge and adsorption isotherm experiments. Thermodynamic parameters estimated from both Langmuir and surface complexation models showed that the adsorption of both metals was endothermic. Values obtained for the adsorption enthalpies from both modeling schemes were similar for both cations. Estimates of the adsorption entropies were model-dependent: Langmuir parameters yielded positive entropies, while some of the surface complexation parameters generated negative adsorption entropies. Copyright 1999 Academic Press.

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Section: Adsorption Edgessupporting

confidence: 77%

The Influence of Temperature on the Adsorption of Cadmium(II) and Cobalt(II) on Goethite

Angove

Wells

Johnson

1999

Journal of Colloid and Interface Science

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“…If nickel were adsorbed as the hydroxide or as the oxide, then the binding energy would be expected to be equivalent to that for Ni(OH)2 or for NiO. Recent data by Tewari and Lee (1975) for adsorption of cobalt on metal oxides and by Koppelman et al (1976) for the adsorption of chromium and cobalt on clay minerals indicate that binding energies for metal hydroxides adsorbed on metal oxides or on clay mineral substrates are equal to the binding energy for the neat metal hydroxide or metal oxide. This data indicates that XPS binding energy data may be used as an aid in identifying the chemical nature of materials adsorbed on substrates.…”

Section: Resultsmentioning

confidence: 99%

“…Measurements of the binding energies of aluminum in a variety of materials have revealed that binding energies are affected by stoichiometric changes in composition (Lindsay et al, 1973), but are not affected by alterations in coordination geometry (Anderson and Swartz, 1974). XPS studies of metal ions adsorbed on mineral surfaces have been valuable in describing the chemical nature of cobalt on metal oxides (Tewari and Lee, 1975) of iron on clay minerals (Koppelman and Dillard, 1975) and heavy metals on montmorillonite (Counts et al, 1973). The of XPS in studying the mechanism of adsorption of phosphates and silicates on gibbsite has been reported (Alvarez et al, 1976).…”

Section: Introductionmentioning

confidence: 99%

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

Koppelman

Dillard

1977

Clays and clay miner.

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Abstract--The adsorption of Ni(II) and Cu(II) on to the clay minerMs kaolinite, chlorite, and illite has been investigated. The quantity of Ni(II) at pH 6 and Cu(II) at pH 5 adsorbed has been found to vary in the manner chlorite > illite > kaolinite. Examination of the mode of bonding of the metal ions to the clay minerals using X-ray photoelectron spectroscopy (XPS) has been carried out. Comparison of the binding energies for metal ions in octahedral sites in selected minerals (reference minerals) and in simple nickel and copper containing compounds with values for Ni(II) and Cu(II) adsorbed on chlorite indicate that nickel(II) is probably bound as the aquo ion while copper(II) may be adsorbed as Cu(OH) § INTRODUCTION

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“…They suggested a change from a dominantly aquo surface complex to a more hydroxide-like complex but one that is not identical to the solid hydroxide phase most likely to precipitate. Other XPS studies of Co(II) complexes on ~'-A1203 suggest a correlation between hydrolysis, adsorption, and the formation of aquo-type complexes at low pH and possible formation of a surface precipitate at high pH (Tewari et al, 1972;Tewari and Lee, 1975;Tewari and McIntyre, 1975). Cobalt and Ni sorption on hectorite and montmorillonite studied by XPS (Davison et al, 1991) supported previous results indicating the formation of a hydroxidelike species at high pH and no change in the binding energies of the sorbed species after successive washings, implying strong bonding of the cation to the surface.…”

Section: Spectroscopic Studies Of Sorbed Metal Ionsmentioning

confidence: 96%

Molecular Structure and Binding Sites of Cobalt(II) Surface Complexes on Kaolinite from X-Ray Absorption Spectroscopy

O’Day

Parks

Brown

1994

Clays and clay miner.

127

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Abstract--X-ray absorption spectroscopy (XAS) was used to determine the local molecular environment of Co(II) surface complexes sorbed on three different kaolinites at ambient temperature and pressure in contact with an aqueous solution. Interatomic distances and types and numbers of backscattering atoms have been derived from analysis of the extended X-ray absorption fine structure (EXAFS). These data show that, at the lowest amounts of Co uptake on kaolinite (0.20--0.32 ~mol m-2), Co is surrounded by ~60 atoms at 2.04-2.08 A and a small number orAl or Si atoms (N = 0.6-1.5) at two distinct distances, 2.67-2.72 A and 3.38-3.43/~. These results indicate that Co bonds to the kaolinite surface as octahedrally coordinated, bidentate inner-sphere mononuclear complexes at low surface coverages, confirming indirect evidence from solution studies that a fraction of sorbed Co forms strongly bound complexes on kaolinite. In addition to inner-sphere complexes identified by EXAFS spectroscopy, solution studies provide evidence for the presence of weakly bound, outer-sphere Co complexes that cannot be detected directly by EXAFS. One orientation for inner-sphere complexes indicated by XAS is bidentate bonding of Co to oxygen atoms at two A1-O-Si edge sites or an A1-O-Si and AI-OH (inner hydroxyl) edge site, i.e., comersharing between Co octahedra and AI and Si potyhedra. At slightly higher surface sorption densities (0.51-0.57/~mol m-2), the presence of a small number of second-neighbor Co atoms (average Nco < 1) at 3.10-3.13/~ indicates the formation of oxy-or hydroxy-bridged, multinuclear surface complexes in addition to mononuclear complexes. At these surface coverages, Co-Co and Co-AI/Si distances derived from EXAFS are consistent with edge-sharing between Co and AI octahedra on either edges or (001) faces of the aluminol sheet in kaolinite. Multinuclear complexes form on kaolinite at low surface sorption densities equivalent to < 5% coverage by a monolayer of oxygen-ligated Co octahedra over the N2-BET surface area. These spectroscopic results have several implications for macroscopic modeling of metal ion uptake on kaolinite: 1) Primary binding sites on the kaolinite surface at low uptake are edge, non-bridging AI-OH inner hydroxyl sites and edge AI-O-Si bridging oxygen sites, not Si-OH sites typically assumed in sorption models; 2) specific adsorption of Co is via bidentate, inner-sphere complexation; and 3) at slightly higher uptake but still a small fraction of monolayer coverage, formation of Co multinuclear complexes, primarily edge-sharing with A1-OH octahedra, begins to dominate sorption.

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Adsorption of Co(II) at the oxide-water interface

Cited by 194 publications

References 11 publications

The Influence of Temperature on the Adsorption of Cadmium(II) and Cobalt(II) on Goethite

The Influence of Temperature on the Adsorption of Cadmium(II) and Cobalt(II) on Goethite

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

Molecular Structure and Binding Sites of Cobalt(II) Surface Complexes on Kaolinite from X-Ray Absorption Spectroscopy

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