An Analytical Isotherm Equation (CONICA) for Nonideal Mono- and Bidentate Competitive Ion Adsorption to Heterogeneous Surfaces
| Autor: | Johannes C.M. de Wit, David G. Kinniburgh, Sipko L.J. Mous, Willem H. van Riemsduk, Luuk K. Koopal |
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| Rok vydání: | 1996 |
| Předmět: |
Denticity
Proton Proton binding Laboratorium voor Fysische chemie en Kolloïdkunde Stereochemistry Ionic bonding Protonation Sub-department of Soil Quality Ion Biomaterials Colloid and Surface Chemistry Adsorption Humic acid Physical Chemistry and Colloid Science chemistry.chemical_classification isotherm Sectie Bodemkwaliteit humic Surfaces Coatings and Films Electronic Optical and Magnetic Materials chemistry adsorption copper proton binding Physical chemistry heterogeneity |
| Zdroj: | Journal of Colloid and Interface Science 183 (1996) Journal of Colloid and Interface Science, 183, 35-50 |
| ISSN: | 0021-9797 |
| DOI: | 10.1006/jcis.1996.0516 |
| Popis: | Analytical isotherm equations for the competitive binding of protons and other cations to heterogeneous surfaces have been derived. These extend our earlier nonideal competitive adsorption (NICA) equation by considering bidentate as well as monodentate binding of ions. The protonation of these bidentate sites occurs in two COnsecutive steps. The CONICA model equations separate the apparent heterogeneity into a generic heterogeneity characteristic of all of the surface sites and an ion-specific contribution characteristic of each type of ion. The CONICA model was combined with a simple Donnan model to account for electrostatic effects and was fitted both to proton binding at various ionic strengths and to the pH-dependent binding of Cu (pH 4, 6, and 8) to a purified peat humic acid. Model fits were good. The measured H+/Cu2+exchange ratio is significantly greater than one for the whole pH range, which indicates the importance of the bidentate binding mechanism for copper. |
| Databáze: | OpenAIRE |
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