Effect of the pore water composition on the diffusive anion transport in argillaceous, low permeability sedimentary rocks
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| Titel: | Effect of the pore water composition on the diffusive anion transport in argillaceous, low permeability sedimentary rocks |
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| Autoren: | Cornelia Wigger, Luc R. Van Loon |
| Weitere Verfasser: | Physiotherapy, Human Physiology and Anatomy, Human Physiology and Sports Physiotherapy Research Group |
| Quelle: | Journal of Contaminant Hydrology. 213:40-48 |
| Verlagsinformationen: | Elsevier BV, 2018. |
| Publikationsjahr: | 2018 |
| Schlagwörter: | Anions, Geologic Sediments, Cation, Helvetic Marl, Sodium, Models, Theoretical, Sodium Chloride, 01 natural sciences, Permeability, Diffusion, Calcium Chloride, Ionic strength, Argillaceous rocks, Bottleneck pores, Hydrology, Opalinus Clay, Groundwater, Porosity, 0105 earth and related environmental sciences |
| Beschreibung: | The effect of the pore water composition on the diffusive anion transport was studied for two different argillaceous, low permeability sedimentary rocks, Opalinus Clay (OPA) and Helvetic Marl (HM). The samples were saturated with different solutions with varying molar concentration and different main cations in the solution: NaCl based pore solutions and CaCl2 based pore solutions. The total porosity was measured by through-diffusion experiments with the neutral tracer HTO. Experiments performed in NaCl solutions resulted in a porosity of 0.12 for OPA and 0.03 for HM, and are consistent with results of the experiments in CaCl2 solutions. The total porosity was independent of the molar concentration, in contrast to the measured anion porosity, which increased with increasing molar concentration. It could further be observed that the pore solution based on the bivalent cation calcium shielded the negative surface charge stronger than the monovalent cation sodium, resulting in a larger measureable anion-accessible porosity in the case of CaCl2 solutions. The data was modelled based on an adapted Donnan approach of Birgersson and Karnland (2009). The model had to be adjusted with a permanent free, uncharged porosity, as well as with structural information on the permanent anion exclusion because of so-called bottleneck pores. Both parameters can only be evaluated from experiments. Nevertheless, taking these two adaptions into account, the effect of varying pore water compositions on the anion-accessible porosity of the investigated argillaceous rocks could be satisfactorily described. |
| Publikationsart: | Article |
| Sprache: | English |
| ISSN: | 0169-7722 |
| DOI: | 10.1016/j.jconhyd.2018.05.001 |
| Zugangs-URL: | https://pubmed.ncbi.nlm.nih.gov/29776662 https://ui.adsabs.harvard.edu/abs/2018JCHyd.213...40W/abstract https://pubmed.ncbi.nlm.nih.gov/29776662/ http://europepmc.org/abstract/MED/29776662 https://www.sciencedirect.com/science/article/pii/S0169772217302772 https://www.dora.lib4ri.ch/psi/islandora/object/psi:5249 https://pubag.nal.usda.gov/catalog/6330396 https://biblio.vub.ac.be/vubir/effect-of-the-pore-water-composition-on-the-diffusive-anion-transport-in-argillaceous-low-permeability-sedimentary-rocks(6b37198a-432f-4532-b39c-091ef084e392).html |
| Rights: | Elsevier TDM |
| Dokumentencode: | edsair.doi.dedup.....53e9fc02bf0eac42e31739b572be2c0f |
| Datenbank: | OpenAIRE |
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Nájsť tento článok vo Web of Science | Abstract: | The effect of the pore water composition on the diffusive anion transport was studied for two different argillaceous, low permeability sedimentary rocks, Opalinus Clay (OPA) and Helvetic Marl (HM). The samples were saturated with different solutions with varying molar concentration and different main cations in the solution: NaCl based pore solutions and CaCl2 based pore solutions. The total porosity was measured by through-diffusion experiments with the neutral tracer HTO. Experiments performed in NaCl solutions resulted in a porosity of 0.12 for OPA and 0.03 for HM, and are consistent with results of the experiments in CaCl2 solutions. The total porosity was independent of the molar concentration, in contrast to the measured anion porosity, which increased with increasing molar concentration. It could further be observed that the pore solution based on the bivalent cation calcium shielded the negative surface charge stronger than the monovalent cation sodium, resulting in a larger measureable anion-accessible porosity in the case of CaCl2 solutions. The data was modelled based on an adapted Donnan approach of Birgersson and Karnland (2009). The model had to be adjusted with a permanent free, uncharged porosity, as well as with structural information on the permanent anion exclusion because of so-called bottleneck pores. Both parameters can only be evaluated from experiments. Nevertheless, taking these two adaptions into account, the effect of varying pore water compositions on the anion-accessible porosity of the investigated argillaceous rocks could be satisfactorily described. |
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| ISSN: | 01697722 |
| DOI: | 10.1016/j.jconhyd.2018.05.001 |