Treatment of boundary conditions in through-diffusion: A case study of 85Sr2+ diffusion in compacted illite

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Treatment of boundary conditions in through-diffusion: A case study of 85Sr2+ diffusion in compacted illite. / Glaus, M.A.; Aertsens, Marc; Maes, Norbert; Van Laer, Liesbeth; Van Loon, L.R.

In: Journal of Contaminant Hydrology, Vol. 177-178, 06.2015, p. 239-248.

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@article{8ba156a024544c5d8e293ff4b281e9b3,
title = "Treatment of boundary conditions in through-diffusion: A case study of 85Sr2+ diffusion in compacted illite",
abstract = "Valuable techniques to measure effective diffusion coefficients in porousmedia are an indispensable prerequisite for a proper understanding of the migration of chemical-toxic and radioactive micropollutants in the subsurface and geosphere. This article discusses possible pitfalls and difficulties in the classical through-diffusion technique applied to situations where large diffusive fluxes of cations in compacted clay minerals or clay rocks occur. The results obtained from a benchmark study, in which the diffusion of 85Sr2+ tracer in compacted illite has been studied using different experimental techniques, are presented. It is shown that these techniques may yield valuable results provided that an appropriate model is used for numerical simulations. It is shown that effective diffusion coefficients may be systematically underestimated when the concentration at the downstream boundary is not taken adequately into account in modelling, even for very low concentrations. A criterion is derived for quasi steady-state situations, by which it can be decided whether the simplifying assumption of a zero-concentration at the downstream boundary in through-diffusion is justified or not. The application of the criterion requires knowledge of the effective diffusion coefficient of the clay sample. Such knowledge is often absent or only approximately available during the planning phase of a diffusion experiment.",
keywords = "Clay, illite, strontium, through-diffusion, method",
author = "M.A. Glaus and Marc Aertsens and Norbert Maes and {Van Laer}, Liesbeth and {Van Loon}, L.R.",
note = "Score = 10",
year = "2015",
month = "6",
doi = "10.1016/j.jconhyd.2015.03.010",
language = "English",
volume = "177-178",
pages = "239--248",
journal = "Journal of Contaminant Hydrology",
issn = "0169-7722",
publisher = "Elsevier",

}

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TY - JOUR

T1 - Treatment of boundary conditions in through-diffusion: A case study of 85Sr2+ diffusion in compacted illite

AU - Glaus, M.A.

AU - Aertsens, Marc

AU - Maes, Norbert

AU - Van Laer, Liesbeth

AU - Van Loon, L.R.

N1 - Score = 10

PY - 2015/6

Y1 - 2015/6

N2 - Valuable techniques to measure effective diffusion coefficients in porousmedia are an indispensable prerequisite for a proper understanding of the migration of chemical-toxic and radioactive micropollutants in the subsurface and geosphere. This article discusses possible pitfalls and difficulties in the classical through-diffusion technique applied to situations where large diffusive fluxes of cations in compacted clay minerals or clay rocks occur. The results obtained from a benchmark study, in which the diffusion of 85Sr2+ tracer in compacted illite has been studied using different experimental techniques, are presented. It is shown that these techniques may yield valuable results provided that an appropriate model is used for numerical simulations. It is shown that effective diffusion coefficients may be systematically underestimated when the concentration at the downstream boundary is not taken adequately into account in modelling, even for very low concentrations. A criterion is derived for quasi steady-state situations, by which it can be decided whether the simplifying assumption of a zero-concentration at the downstream boundary in through-diffusion is justified or not. The application of the criterion requires knowledge of the effective diffusion coefficient of the clay sample. Such knowledge is often absent or only approximately available during the planning phase of a diffusion experiment.

AB - Valuable techniques to measure effective diffusion coefficients in porousmedia are an indispensable prerequisite for a proper understanding of the migration of chemical-toxic and radioactive micropollutants in the subsurface and geosphere. This article discusses possible pitfalls and difficulties in the classical through-diffusion technique applied to situations where large diffusive fluxes of cations in compacted clay minerals or clay rocks occur. The results obtained from a benchmark study, in which the diffusion of 85Sr2+ tracer in compacted illite has been studied using different experimental techniques, are presented. It is shown that these techniques may yield valuable results provided that an appropriate model is used for numerical simulations. It is shown that effective diffusion coefficients may be systematically underestimated when the concentration at the downstream boundary is not taken adequately into account in modelling, even for very low concentrations. A criterion is derived for quasi steady-state situations, by which it can be decided whether the simplifying assumption of a zero-concentration at the downstream boundary in through-diffusion is justified or not. The application of the criterion requires knowledge of the effective diffusion coefficient of the clay sample. Such knowledge is often absent or only approximately available during the planning phase of a diffusion experiment.

KW - Clay

KW - illite

KW - strontium

KW - through-diffusion

KW - method

UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/ezp_139549

UR - http://knowledgecentre.sckcen.be/so2/bibref/12642

U2 - 10.1016/j.jconhyd.2015.03.010

DO - 10.1016/j.jconhyd.2015.03.010

M3 - Article

VL - 177-178

SP - 239

EP - 248

JO - Journal of Contaminant Hydrology

JF - Journal of Contaminant Hydrology

SN - 0169-7722

ER -

ID: 155781