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Complexation mechanism of Pb2+ at the ferrihydrite-water interface: The role of Al-substitution.
- Source :
-
Chemosphere . Nov2022:Part 1, Vol. 307, pN.PAG-N.PAG. 1p. - Publication Year :
- 2022
-
Abstract
- Ferrihydrite is a poorly crystalline iron (hydr)oxide and highly efficient adsorbent for heavy metals. Al-substitution in ferrihydrite is ubiquitous in nature. However, the effect of Al-substitution on the surface reactivity of ferrihydrite remains unclear due to its low crystallinity. The present study aims to clarify the microstructure and interfacial reaction of Al-substituted ferrihydrite. Al-substitution had little effect on the morphology and surface site density of ferrihydrite, while the presence of ≡AlOH−0.5 sites resulted in higher proton affinity and surface positive charge of ferrihydrite. Besides, the affinity constant of Pb2+ adsorption on the surface of ferrihydrite decreased at higher Al content, which further decreased the adsorption performance of ferrihydrite for Pb2+. The modeling results revealed that bidentate complex was the dominant Pb complexation species on the surface of ferrihydrite, which was less affected by Al-substitution. The present study provides important insights into the effect of Al-substitution on the interfacial reaction at the ferrihydrite-water interface. The obtained parameters may facilitate the future advance of surface complexation model. [Display omitted] • Pb2+ adsorption on Al-substituted ferrihydrite was studied by CD-MUSIC model. • The presence of Al–O sites contributed to a higher proton affinity and surface charge. • Al-substitution decreased the adsorption performance of ferrihydrite for Pb2+. • Bidentate complexes were the dominant Pb species on the surface of ferrihydrite. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00456535
- Volume :
- 307
- Database :
- Academic Search Index
- Journal :
- Chemosphere
- Publication Type :
- Academic Journal
- Accession number :
- 159189357
- Full Text :
- https://doi.org/10.1016/j.chemosphere.2022.135627