Metal ion binding to iron oxides

Ponthieu, Marie; Juillot, Farid; Hiemstra, Tjisse; Riemsdijk, W.H. van; Benedetti, Marc F.

doi:10.1016/j.gca.2006.02.021

Cited by 144 publications

(100 citation statements)

References 65 publications

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“…(2000) suggested six possible bonding geometries for adsorption onto goethite. Ponthieu et al (2006) indicated that a consistent description of proton and metal ion binding is possible for goethite and HFO. We used the CrystalMakere to construct the 2-nm (4 Â 4 Â 2 unit cells) and 6-nm domains (10 Â 10 Â 7 unit cells), assuming ferrihydrite particles are perfect periodic stacking of unit cells and ignoring disorder and defects (e.g., stacking faults) of the structure.…”

Section: Acknowledgmentsmentioning

confidence: 96%

Lead coprecipitation with iron oxyhydroxide nano-particles

Lü

Nuhfer

Kelly

et al. 2011

Geochimica et Cosmochimica Acta

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Pb 2+ and Fe 3+ coprecipitation was studied with sorption edge measurements, desorption experiments, sorbent aging, High Resolution Transmission and Analytical Electron Microscopy (HR TEM-AEM), and geochemical modeling. Companion adsorption experiments were also conducted for comparison. The macroscopic chemical and near atomic scale HRTEM data supplemented our molecule scale analysis with EXAFS (Kelly et al., 2008). Coprecipitation of Pb 2+ with ferric oxyhydroxides occurred at $pH 4 and is more efficient than adsorption in removing Pb 2+ from aqueous solutions at similar sorbate/sorbent ratios and pH. X-ray Diffraction (XRD) shows peaks of lepidocrocite and two additional broad peaks similar to fine particles of 2-line ferrihydrite (2LFh). HRTEM of the Pb-Fe coprecipitates shows a mixture of 2-6 nm diameter spheres and 8-20 by 200-300 nm needles, both uniformly distributed with Pb 2+ . Geochemical modeling shows that surface complexation models fit the experimental data of low Pb:Fe ratios when a high site density is used. Desorption experiments show that more Pb 2+ was released from loaded sorbents collected from adsorption experiments than from Pb to Fe coprecipitates at dilute EDTA concentrations. Desorbed Pb 2+ versus dissolved Fe 3+ data show a linear relationship for coprecipitation (CPT) desorption experiments but a parabolic relationship for adsorption (ADS) experiments.Based on these results, we hypothesize that Pb 2+ was first adsorbed onto the nanometer-sized, metastable, iron oxyhydroxide polymers of 2LFh with domain size of 2-3 nm. As these nano-particles assembled into larger particles, some Pb 2+ was trapped in the iron oxyhydroxide structure and re-arranged to form solid solutions. Therefore, the CPT contact method produced more efficient removal of Pb 2+ than the adsorption contact method, and Pb 2+ bound in CPT solids represent a more stable sequestration of Pb 2+ in the environment than Pb 2+ adsorbed on iron oxyhydroxide surfaces.

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Section: Acknowledgmentsmentioning

confidence: 96%

Lead coprecipitation with iron oxyhydroxide nano-particles

Lü

Nuhfer

Kelly

et al. 2011

Geochimica et Cosmochimica Acta

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“…Ideally, SCM may predict changes in situations where experimental data are not available or difficult to collect. Surface complexation models have widely been used to estimate the distribution of metaland oxyanions between solution and mineral surfaces (Ali and Dzombak, 1996;Antelo et al, 2005;Boily, 1999;Christl and Kretzschmar, 1999;Criscenti and Sverjensky, 1999;Dzombak and Morel, 1990;Lutzenkirchen, 2004;Ponthieu et al, 2006;Tadanier and Eick, 2002).…”

Section: Introductionmentioning

confidence: 99%

Nanoparticles in natural systems I: The effective reactive surface area of the natural oxide fraction in field samples

Hiemstra

Antelo

Rahnemaie

et al. 2010

Geochimica et Cosmochimica Acta

145

185

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“…by 17 considering various complexes bound to different major sites [27] , are difficult to constrain 18 since this requires confirmation of the assumed surface structures by means of EXAFS 19 spectroscopy at very low lead(II) concentrations (which are difficult to get with today's 20 generation of synchrotrons). It is interesting to note, however, that the Pb 2+ sorption data, 21 despite the three different site classes, can be described well using just one type of 22 surface complexation reaction.…”

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confidence: 99%

Modelling lead(II) sorption to ferrihydrite and soil organic matter

et al. 2011

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Lead(II) adsorption to soil organic matter and iron (hydr)oxides is strong, and may control the geochemical behaviour of this metal. Here, we report the adsorption of Pb(2+) (i) to 2-line ferrihydrite, and (ii) to a mor layer. The results showed that ferrihydrite has heterogeneous Pb(2+) binding. Use of a surface complexation model indicated that similar to 1% of the surface sites adsorbed Pb(2+) more strongly than the remaining 99 %. Although only one surface complexation reaction was used (a bidentate complex of the composition (equivalent to FeOH)(2)Pb(+)), three classes of sites with different affinity for Pb(2+) were needed to simulate Pb(2+) binding correctly over all Pb/Fe ratios analysed. For the mor layer, Pb(2+) sorption was much stronger than current models for organic complexation suggest. The results could be described by the Stockholm Humic Model when the binding heterogeneity was increased, and when it was assumed that 0.2% of the binding sites were specific for Pb. Use of revised model parameters for nine Vietnamese soils suggest that lead(II) binding was more correctly simulated than before. Thus, underestimation of lead(II) sorption to both (hydr) oxide surfaces and organic matter may explain the failure of previous geochemical modelling attempts for lead(II).

QC 20111103

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Metal ion binding to iron oxides

Cited by 144 publications

References 65 publications

Lead coprecipitation with iron oxyhydroxide nano-particles

Lead coprecipitation with iron oxyhydroxide nano-particles

Nanoparticles in natural systems I: The effective reactive surface area of the natural oxide fraction in field samples

Modelling lead(II) sorption to ferrihydrite and soil organic matter

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