Phosphate adsorption on γ-alumina: a surface complex model based on surface characterization and zeta potential measurements
Résumé
An innovative approach using solid/liquid interface characterization (zetametry measurements, ATR-IR), coupled with ex situ FTIR has been used to build a phosphate complexation model at the alumina surface via the PHREEQC software. According to the phosphorus coverage impregnated on the alumina surface, two mechanisms of adsorption have been identified: a specific surface complex adsorbed on the predominant alumina facet and a surface precipitation process. At low phosphorus coverage (P coverage<1.2 at/nm²), the adsorption proceeds mainly through a monodentate complex adsorbed on µ 1-Al IV-OH sites located on the (110) facet, a bidentate involving µ 1-Al V-OH (110) is also discussed. However, the surface concentration of these particular sites is limited. Thus, above the threshold of 1.2 at/nm², a surface precipitation occurs with the formation of an amorphous AlPO 4 phase, experimentally observed by FTIR and zetametry measurements.
Domaines
Chimie
Fichier principal
Article Phosphate Teddy_Vf_modifacceptées.pdf (1.42 Mo)
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Phosphate SI.pdf (284.66 Ko)
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