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Title: A Multi-Scale Assessment of Pb(II) Sorption on Dolomite

Abstract

Macroscopic sorption studies indicated that Pb sorption capacity was independent of pH over the pH range 5-7, while sorption as a function of reaction time up to two weeks for systems with no bulk precipitate phases showed continuous Pb uptake on dolomite. This could be due to diffusion of Pb into the micropores of dolomite as well as an increase in surface sites caused by particle size reduction during suspension mixing. Normalized XANES spectra for systems undersaturated with respect to Pb carbonate precipitates resembled the spectrum of Pb{sub 4}(OH){sup 4+}{sub 4}, suggesting that Pb is mainly coordinated to dolomite as an inner-sphere surface complex. On the other hand, the XANES spectrum for 10{sup -3} M Pb at 1 atm CO{sub 2(g)} in a 2 M Mg(NO{sub 3}){sub 2} background electrolyte solution resembled that of cerussite, while a sample at 5x10{sup -4} M Pb in equilibrium with air and 2 M Mg(NO{sub 3}){sub 2} resembled that of hydrocerussite. EXAFS analyses of sorption samples in chloride solutions showed that there were only first-shell contributions under 1 atm CO{sub 2(g)}, while higher shell contributions from Ca/Mg were seen at 10{sup -3.42} atm CO{sub 2(g)}. On the other hand, EXAFS samples prepared in nitratemore » solutions showed noticeable differences in speciation under different reaction conditions-from outer-sphere surface complexes at low Pb concentrations and pH, to inner-sphere surface complexes at moderate Pb concentrations and neutral pH, to the formation of Pb carbonate precipitates at the highest Pb loadings.« less

Authors:
; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
914121
Report Number(s):
BNL-78689-2007-JA
Journal ID: ISSN 0021-9797; JCISA5; TRN: US0801556
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: J. Colloid Interface Sci.; Journal Volume: 298; Journal Issue: 1
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; AIR; CAPACITY; CARBONATES; CHLORIDES; DIFFUSION; DOLOMITE; ELECTROLYTES; NITRATES; PARTICLE SIZE; SORPTION; SPECTRA; NSLS; national synchrotron light source

Citation Formats

Lee,S., Dyer, J., Sparks, D., Scrivner, N., and Elzinga, E. A Multi-Scale Assessment of Pb(II) Sorption on Dolomite. United States: N. p., 2006. Web. doi:10.1016/j.jcis.2005.12.022.
Lee,S., Dyer, J., Sparks, D., Scrivner, N., & Elzinga, E. A Multi-Scale Assessment of Pb(II) Sorption on Dolomite. United States. doi:10.1016/j.jcis.2005.12.022.
Lee,S., Dyer, J., Sparks, D., Scrivner, N., and Elzinga, E. Sun . "A Multi-Scale Assessment of Pb(II) Sorption on Dolomite". United States. doi:10.1016/j.jcis.2005.12.022.
@article{osti_914121,
title = {A Multi-Scale Assessment of Pb(II) Sorption on Dolomite},
author = {Lee,S. and Dyer, J. and Sparks, D. and Scrivner, N. and Elzinga, E.},
abstractNote = {Macroscopic sorption studies indicated that Pb sorption capacity was independent of pH over the pH range 5-7, while sorption as a function of reaction time up to two weeks for systems with no bulk precipitate phases showed continuous Pb uptake on dolomite. This could be due to diffusion of Pb into the micropores of dolomite as well as an increase in surface sites caused by particle size reduction during suspension mixing. Normalized XANES spectra for systems undersaturated with respect to Pb carbonate precipitates resembled the spectrum of Pb{sub 4}(OH){sup 4+}{sub 4}, suggesting that Pb is mainly coordinated to dolomite as an inner-sphere surface complex. On the other hand, the XANES spectrum for 10{sup -3} M Pb at 1 atm CO{sub 2(g)} in a 2 M Mg(NO{sub 3}){sub 2} background electrolyte solution resembled that of cerussite, while a sample at 5x10{sup -4} M Pb in equilibrium with air and 2 M Mg(NO{sub 3}){sub 2} resembled that of hydrocerussite. EXAFS analyses of sorption samples in chloride solutions showed that there were only first-shell contributions under 1 atm CO{sub 2(g)}, while higher shell contributions from Ca/Mg were seen at 10{sup -3.42} atm CO{sub 2(g)}. On the other hand, EXAFS samples prepared in nitrate solutions showed noticeable differences in speciation under different reaction conditions-from outer-sphere surface complexes at low Pb concentrations and pH, to inner-sphere surface complexes at moderate Pb concentrations and neutral pH, to the formation of Pb carbonate precipitates at the highest Pb loadings.},
doi = {10.1016/j.jcis.2005.12.022},
journal = {J. Colloid Interface Sci.},
number = 1,
volume = 298,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}
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