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Updated: Jun 26, 2026
09:37
Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
Competition between selenium (IV) and silicic acid on the hematite surface.
Norbert Jordan1, Nicolas Marmier, Claire Lomenech
1Université de Nice-Sophia-Antipolis, Laboratoire de Radiochimie, Sciences Analytiques et Environnement, 28 Avenue Valrose, 06108 Nice Cedex 2, France. jordan@unice.fr
Chemosphere
|December 27, 2008
Summary
Selenium (IV) and silicic acid compete for binding sites on hematite surfaces. This competition affects selenium retention, as confirmed by surface complexation modeling and experimental data in ternary systems.
Area of Science:
- Environmental Chemistry
- Geochemistry
- Surface Science
Background:
- Selenium (IV) and silicic acid are common environmental contaminants.
- Hematite (alpha-Fe(2)O(3)) is a prevalent mineral in soils and sediments.
- Understanding their interactions is crucial for predicting contaminant fate and transport.
Purpose of the Study:
- To investigate the competitive sorption behavior between selenium (IV) and silicic acid on hematite.
- To model and predict the influence of silicic acid on selenium (IV) retention.
- To validate surface complexation models for ternary systems.
Main Methods:
- Batch sorption experiments were conducted to study selenium (IV) and silicic acid sorption individually and competitively.
- The 2-pK surface complexation model was employed.
- The FITEQL 4.0 program was used for fitting experimental data and determining surface complexation constants.
Main Results:
- Specific inner-sphere surface complexes were identified for both selenite ions (FeSeO(3)(-) and FeHSeO(3)) and silicic acid (FeH(3)SiO(4) and FeH(2)SiO(4)(-)).
- A significant competition between selenium (IV) and silicic acid for hematite surface sites was experimentally observed.
- The developed surface complexation model accurately predicted the experimental outcomes in the ternary system.
Conclusions:
- Selenium (IV) and silicic acid exhibit competitive sorption on hematite.
- The surface complexation model effectively describes the interactions in the ternary system.
- This study provides a quantitative understanding of selenium and silica interactions with iron oxides.
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