Mechanism of adsorption of cobalt(2+) and nickel(2+) ions on the "pure and fluorinated .gamma.-alumina/electrolyte solution" interface

Role of natural nanoparticles on the speciation of Ni in andosols of la Reunion

“…This adsorption level was about twofold lower than levels reported in the literature for Ni adsorption on aluminum oxide, e.g. 74 lmol g À1 Ni on c-alumina (Vordonis et al, 1992) at pH 6.3. Considering the specific surface of 228 m 2 g À1 , this adsorption represents only 0.11 atom of Ni per nm 2 (as compared to 0.6 in the study of Vordonis et al, 1992), which is far from what could be expected for nanoparticles with such a high surface area.…”

Adsorption of cobalt species on the interface, which is developed between aqueous solution and metal oxides used for the preparation of supported catalysts: a critical review

“…[20,21,37,38,112]) or the homogeneous one-site/two-pK model (e.g., Refs. [25,26,28,29,118,119]). The nonelectrostatic approach, in which a Langmuir model for the adsorption is simply implied, is obviously nonrealistic as it does not take into account the charged surface and the development of the interfacial region.…”

“…In cases where the development of the double layer has been taken into account, the TLM (e.g., Refs. [25,26,28,29]) or the diffuse layer model (e.g., Refs. [118,119]) has been used to describe the adsorption data.…”

“…Vordonis et al [25] and Spanos and Lycourghiotis [26] studied the mechanism of adsorption from aqueous suspension of Co(II) ions on the g-alumina surface as well as on g-alumina doped with various amounts of F À ions. Using Co(NO 3 ) 2 Á6H 2 O aqueous solutions, they worked under conditions that resulted in surface Co(II) densities lower or equal to 0.6 Amol Co m À 2 corresponding to a number of theoretical Co(H 2 O) 6 2 + surface layers lower or equal to 0.18.…”

Structure of Co(II) Species Formed on the Surface of γ-Alumina Upon Interfacial Deposition

“…Concerning γ-alumina, macroscopic studies, carried out in the context of catalyst preparation, have shown that the Co(II) sorption is pH dependent and not affected by the ionic strength of the solution [18][19][20][21]. Moreover, molecular scale investigation, based on adsorption kinetics and diffuse reflectance spectroscopy [22,23], indicated that Co(II) forms interfacial mono-or bi-dentate inner sphere complexes at low surface coverage and surface precipitate at high surface coverage.…”