skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Uranyl adsorption and surface speciation at the imogolite–water interface: Self-consistent spectroscopic and surface complexation models

Authors:
; ; ; ;
Publication Date:
Research Org.:
Subsurface Biogeochemical Research (SBR)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER)
OSTI Identifier:
1154209
Resource Type:
Journal Article
Resource Relation:
Journal Name: Geochimica et Cosmochimica Acta; Journal Volume: 70; Journal Issue: 10
Country of Publication:
United States
Language:
English

Citation Formats

Yuji,Arai, M.,McBeath, J.R.,Bargar, J.,Joye, and J.A.,Davis. Uranyl adsorption and surface speciation at the imogolite–water interface: Self-consistent spectroscopic and surface complexation models. United States: N. p., 2006. Web. doi:10.1016/j.gca.2006.02.013.
Yuji,Arai, M.,McBeath, J.R.,Bargar, J.,Joye, & J.A.,Davis. Uranyl adsorption and surface speciation at the imogolite–water interface: Self-consistent spectroscopic and surface complexation models. United States. doi:10.1016/j.gca.2006.02.013.
Yuji,Arai, M.,McBeath, J.R.,Bargar, J.,Joye, and J.A.,Davis. Mon . "Uranyl adsorption and surface speciation at the imogolite–water interface: Self-consistent spectroscopic and surface complexation models". United States. doi:10.1016/j.gca.2006.02.013.
@article{osti_1154209,
title = {Uranyl adsorption and surface speciation at the imogolite–water interface: Self-consistent spectroscopic and surface complexation models},
author = {Yuji,Arai and M.,McBeath and J.R.,Bargar and J.,Joye and J.A.,Davis},
abstractNote = {},
doi = {10.1016/j.gca.2006.02.013},
journal = {Geochimica et Cosmochimica Acta},
number = 10,
volume = 70,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2006},
month = {Mon May 01 00:00:00 EDT 2006}
}
  • No abstract prepared.
  • The triple-layer model was used to model the adsorption behavior of Cu(II), Pb(II), and Zn(II) onto goethite as a function of pH, total dissolved metal (Me) concentration, surface area, and ionic strength. A single reaction involving adsorption of Me{sup 2+} onto negative surface sites as an inner-sphere complex proved successful in describing adsorption of all three metals under the experimental conditions. The calibrated model was validated by comparing model predictions to independent data reported in the literature. A linear-free-energy relationship between the intrinsic surface complexation and the first-hydrolysis equilibrium constants was determined and was used to predict the intrinsic surfacemore » complexation constants for Co(II) and Hg(II). The triple-layer model, using the predicted constants, quantitatively described the adsorption of Co(II), but significantly overpredicted the extent of Hg(II) adsorption.« less
  • Understanding in situ metal surface speciation on mineral surfaces is critical to predicting the natural attenuation of metals in the subsurface environment. In this study, we have demonstrated the novel Ni K-edge X-ray absorption spectroscopy (XAS) measurements needed to understand Ni(II) surface speciation in three synthetic iron oxyhydroxides (ferrihydrite, goethite, and hematite). The adsorption of Ni gradually increases with increasing pH from 5 to 8, and the adsorption edge appears at near the point of zero salt effect (PZSE) of the solids. The results of XAS analysis indicate four different Ni inner-sphere surface species are present. While total Ni surfacemore » species in hematite at pH 6.85 surfaces consist of {approx}63% face-sharing (interatomic distance of Ni-Fe (R{sub Ni-Fe}) {approx}2.9 {angstrom}) and {approx}37% corner-sharing (R{sub Ni-Fe} 4.0 {angstrom}) surface species on iron octahedra, a combination of two different edge-sharing (between NiO{sub 6} and FeO{sub 6} octahedra, in chains or in rows) and corner-sharing surface species are observed in goethite and ferrihydrite at pH 5.09-6.89. In ferrihydrite, approximately 70% of surface species are edge-sharing surface species (in chains) (R{sub Ni-Fe} 3.0 {angstrom}), followed by {approx}30% of edge-sharing species (in rows) (R{sub Ni-Fe} {approx}3.2 {angstrom}) and {approx}3-5% of corner-sharing surface species (R{sub Ni-Fe} 4.0{angstrom}). Goethite contains {approx}54% edge-sharing (R{sub Ni-Fe} 3.0 {angstrom}), {approx}26% edge-sharing (R{sub Ni-Fe} {approx}3.2 {angstrom}), and 20% corner-sharing surface species. These findings indicate that the reactivity and surface speciation of Ni are sensitive to the crystallinity of iron oxyhydroxides. The spectroscopic evidence for multi-Ni surface speciation should be factored into predictions of the transport of Ni in soil-water environments.« less
  • No abstract prepared.
  • No abstract prepared.