Glucose-1-phosphate and Myo-inositol Hexaphosphate Adsorption Mechanisms on Goethite
- M. Ognalaga,
- E. Frossard and
- F. Thomas
This research was performed to elucidate the adsorption mechanisms of two monoester phosphates, glucose-1-phosphate (G1P) and myo-inositol hexaphosphate (I6P), on a synthetic goethite with reference to orthophosphate (Pi). Adsorption isotherms were built and electrophoretic and pH measurements were carried out in order to determine the nature of the adsorbent-adsorbate bonds. The quantity of adsorbed compound reached 5.41 µmol Pi m−2, 5.06 µmol G1P m−2, and 1.37 µmol I6P m−2. The G1P and I6P were adsorbed on the surface hydroxyls of goethite through their phosphate groups. The proposed adsorption mechanism, notwithstanding the nature of the organic moiety, is a specific adsorption by a ligand exchange between the phosphate groups and the surface reactive hydroxyls. Inner-sphere surface complexes are formed between phosphate groups and Fe. Very little dissolution of the goethite occurred during the adsorption of either of the two ligands (G1P and I6P). Tentative configurations of the formed organophosphate-goethite complexes are proposed.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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