Removal of Fluorescein using different iron oxides as adsorbents: Effect of pH
| Autor: | María Luján Ferreira, Elsa H. Rueda, Silvina Pirillo, Laura Maria Cornaglia |
|---|---|
| Rok vydání: | 2008 |
| Předmět: |
Goethite
Surface Properties Inorganic chemistry Spectrum Analysis Raman Ferric Compounds Analytical Chemistry Hydrophobic effect symbols.namesake chemistry.chemical_compound Adsorption Spectroscopy Fourier Transform Infrared Fourier transform infrared spectroscopy Instrumentation Spectroscopy Magnetite Molecular Structure Chemistry Sorption Hydrogen-Ion Concentration Atomic and Molecular Physics and Optics visual_art symbols visual_art.visual_art_medium Fluorescein van der Waals force Raman spectroscopy |
| Zdroj: | Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy. 71:636-643 |
| ISSN: | 1386-1425 |
| Popis: | In this work the adsorption process of Fluorescein (dye with aril-methane group) as a function of pH on three different adsorbents: goethite, Co-goethite, and magnetite has been studied experimentally and theoretically. FTIR and Raman spectroscopy have been performed in an attempt to confirm the structure of surface complexes formed by sorption of the Fluorescein to different iron oxides. Typical anionic adsorption behaviour was observed for this dye onto goethite and Co-goethite whereas the adsorption level was practically constant in the range of pH studied when the adsorbent was magnetite. The diffuse layer model was employed to fit the experimental results. The surface complexes proposed from the adsorption data were in agreement with the patterns obtained from FTIR and Raman spectroscopy. The surface structure of the oxides affects the adsorption process and the final adsorbed amount at the equilibrium. Our model of diffuse double layer with the addendum of the effect of hydrophobic forces fits well the adsorption data of Fluorescein on iron oxides at different pH in the studied range. At lower pH electrostatic forces by ligand-exchange are predominant. In the range of pH 9–11 hydrophobic forces are managing the Fluorescein adsorption on the iron oxides, with the formation of outer-sphere complexes through van der Waals/hydrophobic forces. It is interesting that in the three iron oxides studied, the adsorbed amount in this range is similar. |
| Databáze: | OpenAIRE |
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