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Kinetics of Cd sorption, desorption and fixation by calcite : a long-term radiotracer study.

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Kinetics of Cd sorption, desorption and fixation by calcite : a long-term radiotracer study. / Ahmed, Imad A. M.; Crout, Neil M. J.; Young, Scott D.
In: Geochimica et Cosmochimica Acta, Vol. 72, No. 6, 15.03.2008, p. 1498-1512.

Research output: Contribution to Journal/MagazineJournal articlepeer-review

Harvard

Ahmed, IAM, Crout, NMJ & Young, SD 2008, 'Kinetics of Cd sorption, desorption and fixation by calcite : a long-term radiotracer study.', Geochimica et Cosmochimica Acta, vol. 72, no. 6, pp. 1498-1512. https://doi.org/10.1016/j.gca.2008.01.014

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Ahmed IAM, Crout NMJ, Young SD. Kinetics of Cd sorption, desorption and fixation by calcite : a long-term radiotracer study. Geochimica et Cosmochimica Acta. 2008 Mar 15;72(6):1498-1512. doi: 10.1016/j.gca.2008.01.014

Author

Ahmed, Imad A. M. ; Crout, Neil M. J. ; Young, Scott D. / Kinetics of Cd sorption, desorption and fixation by calcite : a long-term radiotracer study. In: Geochimica et Cosmochimica Acta. 2008 ; Vol. 72, No. 6. pp. 1498-1512.

Bibtex

@article{a93907c5084f4f18a3b5dae4822d00a2,
title = "Kinetics of Cd sorption, desorption and fixation by calcite : a long-term radiotracer study.",
abstract = "Time-dependent sorption and desorption of Cd on calcite was studied over 210 days utilizing 109Cd as a tracer to distinguish between {\textquoteleft}labile{\textquoteright} and {\textquoteleft}non-labile{\textquoteright} forms of sorbed Cd. Stabilizing the calcite suspensions for 12 months under atmospheric PCO2 and controlled temperature was necessary to reliably follow Cd dynamics following initial sorption. Results revealed time-dependant Cd sorption and marked desorption hysteresis by calcite under environmentally relevant conditions. Data obtained were fitted to a first-order kinetic model and a concentric shell diffusion model. Both models described the progressive transfer of Cd2+ to a less reactive form within calcite and subsequent desorption of Cd subject to different initial contact times. The kinetic model provided a better fit to the combined sorption and desorption data (R2 = 0.992). It differentiates between two {\textquoteleft}pools{\textquoteright} of sorbed Cd2+ on calcite, {\textquoteleft}labile{\textquoteright} and {\textquoteleft}non-labile{\textquoteright}, in which labile sorbed Cd is in immediate equilibrium with the free Cd2+ ion activity in solution whereas non-labile Cd is kinetically restricted. For the diffusion model (R2 = 0.959), the rate constants describing Cd dynamics in calcite produced a half-life for Cd desorption of 175 d, for release to a {\textquoteleft}zero-sink{\textquoteright} solution. Results from this study allow comment on the likely mechanisms occurring at the calcite surface following long-term Cd sorption.",
keywords = "Calcite, kinetic model, radiotracer, 109Cd, adsorption isotherm, Minimum Description Length",
author = "Ahmed, {Imad A. M.} and Crout, {Neil M. J.} and Young, {Scott D.}",
year = "2008",
month = mar,
day = "15",
doi = "10.1016/j.gca.2008.01.014",
language = "English",
volume = "72",
pages = "1498--1512",
journal = "Geochimica et Cosmochimica Acta",
issn = "0016-7037",
publisher = "Elsevier Limited",
number = "6",

}

RIS

TY - JOUR

T1 - Kinetics of Cd sorption, desorption and fixation by calcite : a long-term radiotracer study.

AU - Ahmed, Imad A. M.

AU - Crout, Neil M. J.

AU - Young, Scott D.

PY - 2008/3/15

Y1 - 2008/3/15

N2 - Time-dependent sorption and desorption of Cd on calcite was studied over 210 days utilizing 109Cd as a tracer to distinguish between ‘labile’ and ‘non-labile’ forms of sorbed Cd. Stabilizing the calcite suspensions for 12 months under atmospheric PCO2 and controlled temperature was necessary to reliably follow Cd dynamics following initial sorption. Results revealed time-dependant Cd sorption and marked desorption hysteresis by calcite under environmentally relevant conditions. Data obtained were fitted to a first-order kinetic model and a concentric shell diffusion model. Both models described the progressive transfer of Cd2+ to a less reactive form within calcite and subsequent desorption of Cd subject to different initial contact times. The kinetic model provided a better fit to the combined sorption and desorption data (R2 = 0.992). It differentiates between two ‘pools’ of sorbed Cd2+ on calcite, ‘labile’ and ‘non-labile’, in which labile sorbed Cd is in immediate equilibrium with the free Cd2+ ion activity in solution whereas non-labile Cd is kinetically restricted. For the diffusion model (R2 = 0.959), the rate constants describing Cd dynamics in calcite produced a half-life for Cd desorption of 175 d, for release to a ‘zero-sink’ solution. Results from this study allow comment on the likely mechanisms occurring at the calcite surface following long-term Cd sorption.

AB - Time-dependent sorption and desorption of Cd on calcite was studied over 210 days utilizing 109Cd as a tracer to distinguish between ‘labile’ and ‘non-labile’ forms of sorbed Cd. Stabilizing the calcite suspensions for 12 months under atmospheric PCO2 and controlled temperature was necessary to reliably follow Cd dynamics following initial sorption. Results revealed time-dependant Cd sorption and marked desorption hysteresis by calcite under environmentally relevant conditions. Data obtained were fitted to a first-order kinetic model and a concentric shell diffusion model. Both models described the progressive transfer of Cd2+ to a less reactive form within calcite and subsequent desorption of Cd subject to different initial contact times. The kinetic model provided a better fit to the combined sorption and desorption data (R2 = 0.992). It differentiates between two ‘pools’ of sorbed Cd2+ on calcite, ‘labile’ and ‘non-labile’, in which labile sorbed Cd is in immediate equilibrium with the free Cd2+ ion activity in solution whereas non-labile Cd is kinetically restricted. For the diffusion model (R2 = 0.959), the rate constants describing Cd dynamics in calcite produced a half-life for Cd desorption of 175 d, for release to a ‘zero-sink’ solution. Results from this study allow comment on the likely mechanisms occurring at the calcite surface following long-term Cd sorption.

KW - Calcite

KW - kinetic model

KW - radiotracer

KW - 109Cd

KW - adsorption isotherm

KW - Minimum Description Length

U2 - 10.1016/j.gca.2008.01.014

DO - 10.1016/j.gca.2008.01.014

M3 - Journal article

VL - 72

SP - 1498

EP - 1512

JO - Geochimica et Cosmochimica Acta

JF - Geochimica et Cosmochimica Acta

SN - 0016-7037

IS - 6

ER -