Interactions of metal hydrous oxides with chelating agents. II. α-Fe2O3—low molecular and polymeric hydroxamic acid species
| Autor: | Egon Matijević, Josef Eisenlauer |
|---|---|
| Rok vydání: | 1980 |
| Předmět: |
chemistry.chemical_classification
Hydroxamic acid Inorganic chemistry Trimer Hematite Surfaces Coatings and Films Electronic Optical and Magnetic Materials Biomaterials chemistry.chemical_compound Acid strength Colloid and Surface Chemistry Isoelectric point Adsorption Deprotonation chemistry visual_art visual_art.visual_art_medium Dissolution |
| Zdroj: | Journal of Colloid and Interface Science. 75:199-211 |
| ISSN: | 0021-9797 |
| DOI: | 10.1016/0021-9797(80)90362-8 |
| Popis: | The interactions of a trimeric (DFOB) and a polymeric (P-11) hydroxamic acid derivative (33 hydroxamic acid groups) with well-defined hydrosols consisting of uniform spherical α-Fe 2 O 3 particles were studied as a function of pH and reactant concentrations. It was found that the uptake of the trimer is relatively small and independent of pH for pH values ≤ the isoelectric point of the hematite. The specific amount adsorbed increases for pH ≥ the isoelectric point, especially when the deprotonation of the hydroxamic groups becomes significant. The simultaneous dissolution of iron(III) in the presence of DFOB after 48 hr of equilibration showed a dependence on pH opposite to that of adsorption. A configurational model for the uptake of this trimeric chelating agent is proposed, which is based on the surface properties of the adsorbent as well as on the solution and complexation properties of the adsorbate. This model explains the kinetic data for the observed adsorption and dissolution phenomena. The corresponding interactions of the polymeric chelating agent with the same hematite sol are characterized by high-affinity adsorption isotherms. The specific amounts of P-11 adsorbed were found to be rather high (2.3 mg m −2 at saturation). No dissolution of hematite particles could be detected in the presence of the polymer, although the complex constant and the acid strength of P-11 are comparable to that of the studied trimer. |
| Databáze: | OpenAIRE |
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