The effect of aging and pH on Pb(II) sorption processes at the calcite-water interface

Ashaki Rouff, Evert Elzinga, Richard J. Reeder, Nicholas S. Fisher

Research output: Contribution to journalArticle

30 Citations (Scopus)

Abstract

The effect of aging on Pb(II) retention in 1 μM Pb, calcite suspensions at pH 7.3, 8.2, and 9.4, under room-temperature conditions, was explored via a combination of batch sorption-desorption experiments and X-ray absorption spectroscopy (XAS). Short-term experiments, up to 12 days, reveal the predominance of an adsorption mechanism at pH 8.2, as confirmed by XAS analysis. Linear-combination fitting of XANES spectra indicates a dual sorption mechanism, with ∼95% adsorbed and ∼5% coprecipitated, and ∼75% adsorbed and ∼25% coprecipitated Pb at pH 7.3 and 9.4, respectively. For long-term sorption, 60-270 days, slow continuous uptake occurs at pH 7.3 and 8.2, determined by EXAFS to be due to an adsorption mechanism. At pH 9.4, no further uptake occurs with aging, and the solid-phase distribution of Pb is commensurate with that for short-term experiments, suggesting that coprecipitated metal may alterthe calcite surface precluding further Pb sorption. Desorption experiments indicate that at pH 7.3 and 8.2 long-term sorption products-constituted primarily of Pb inner-sphere adsorption complexes-are reversibly bound. For aged pH 9.4 samples, significant sorption irreversibility indicates that the coprecipitated component is not readily exchangeable with the aqueous phase, and thus coprecipitation may be effective for long-term metal sequestration.

Original languageEnglish (US)
Pages (from-to)1792-1798
Number of pages7
JournalEnvironmental Science and Technology
Volume40
Issue number6
DOIs
StatePublished - Mar 15 2006
Externally publishedYes

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Calcium Carbonate
Calcite
Sorption
calcite
sorption
Aging of materials
Water
X ray absorption spectroscopy
atomic absorption spectroscopy
adsorption
Adsorption
water
X-ray spectroscopy
Desorption
desorption
experiment
Metals
Experiments
metal
Coprecipitation

All Science Journal Classification (ASJC) codes

  • Environmental Engineering
  • Environmental Science(all)
  • Environmental Chemistry

Cite this

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title = "The effect of aging and pH on Pb(II) sorption processes at the calcite-water interface",
abstract = "The effect of aging on Pb(II) retention in 1 μM Pb, calcite suspensions at pH 7.3, 8.2, and 9.4, under room-temperature conditions, was explored via a combination of batch sorption-desorption experiments and X-ray absorption spectroscopy (XAS). Short-term experiments, up to 12 days, reveal the predominance of an adsorption mechanism at pH 8.2, as confirmed by XAS analysis. Linear-combination fitting of XANES spectra indicates a dual sorption mechanism, with ∼95{\%} adsorbed and ∼5{\%} coprecipitated, and ∼75{\%} adsorbed and ∼25{\%} coprecipitated Pb at pH 7.3 and 9.4, respectively. For long-term sorption, 60-270 days, slow continuous uptake occurs at pH 7.3 and 8.2, determined by EXAFS to be due to an adsorption mechanism. At pH 9.4, no further uptake occurs with aging, and the solid-phase distribution of Pb is commensurate with that for short-term experiments, suggesting that coprecipitated metal may alterthe calcite surface precluding further Pb sorption. Desorption experiments indicate that at pH 7.3 and 8.2 long-term sorption products-constituted primarily of Pb inner-sphere adsorption complexes-are reversibly bound. For aged pH 9.4 samples, significant sorption irreversibility indicates that the coprecipitated component is not readily exchangeable with the aqueous phase, and thus coprecipitation may be effective for long-term metal sequestration.",
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The effect of aging and pH on Pb(II) sorption processes at the calcite-water interface. / Rouff, Ashaki; Elzinga, Evert; Reeder, Richard J.; Fisher, Nicholas S.

In: Environmental Science and Technology, Vol. 40, No. 6, 15.03.2006, p. 1792-1798.

Research output: Contribution to journalArticle

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T1 - The effect of aging and pH on Pb(II) sorption processes at the calcite-water interface

AU - Rouff, Ashaki

AU - Elzinga, Evert

AU - Reeder, Richard J.

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