Barite precipitation in porous media: Impact of pore structure and surface charge on ionic diffusion

Autor: Olivier Bildstein, Vincent Lagneau, V. Detilleux, S. Savoye, Charles Wittebroodt, A. Rajyaguru, J. Wang
Přispěvatelé: Institut des Sciences Appliquées et de la Simulation pour les énergies bas carbone (ISAS), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay, Centre de Géosciences (GEOSCIENCES), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut de Radioprotection et de Sûreté Nucléaire (IRSN), CEA-DES-IRESNE-DTN, BEL V, Laboratoire de Modélisation des Transferts dans l'Environnement (LMTE), Service Mesures et modélisation des Transferts et des Accidents graves (SMTA), Département Technologie Nucléaire (DTN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Département Technologie Nucléaire (DTN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Mines Paris - PSL (École nationale supérieure des mines de Paris), Laboratoire d'étude et de recherche sur les transferts et les interactions dans les sous-sols (IRSN/PSE-ENV/SEDRE/LETIS), Service des déchets radioactifs et des transferts dans la géosphère (IRSN/PSE-ENV/SEDRE), Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN)
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Journal of Contaminant Hydrology
Journal of Contaminant Hydrology, Elsevier, 2021, 242, pp.103851. ⟨10.1016/j.jconhyd.2021.103851⟩
Journal of Contaminant Hydrology, 2021, 242, pp.103851. ⟨10.1016/j.jconhyd.2021.103851⟩
ISSN: 0169-7722
Popis: Several scientific fields such as global carbon sequestration , deep geological radioactive waste disposal, and oil recovery/fracking encounter safety assessment issues originating from pore-scale processes such as mineral precipitation and dissolution. These processes occur in situations where the pore solution contains chemical complexity (such as pH, ionic strength, redox chemistry, etc. …) and the porous matrix contains physical complexity (such as pore size distribution, surface charge, surface roughness , etc. …). Thus, to comprehend the participation of each physicochemical phenomenon on governing mineral precipitation, it is essential to investigate the precipitation behavior of a given mineral in different confined volumes. In this study, a counter-diffusion approach was used to investigate barite precipitation in two porous materials : micritic chalk and compacted kaolinite . The two materials present similar water and anionic tracer diffusivities and total accessible porosities but distinct pore size distributions with pore throats of c.a. 660 nm in chalk versus c.a. 35 nm in kaolinite. X-ray tomography results obtained on the two materials showed a distinct distribution of barite precipitates: a 500 μm-thick homogeneous layer in chalk versus spherical clusters spread in a thickness of 2 mm in kaolinite. Mass balance calculations showed that barite precipitation led to a porosity decrease in the chalk reacted zone from 45% to 12% and in the kaolinite reacted zone from 36% to 34.5%. In contrast, water tracer diffusion experiments showed that diffusivity decreased by a factor of 28 in chalk and by a factor of 1000 in kaolinite. Such a discrepancy was attributed to the difference in the pore size distribution that would lead to the distinct barite precipitation patterns, capable of altering in a very different manner the connectivity within the reacted zone of the two selected porous media . Such local alterations in connectivity linked to pore volume reduction would also magnify surface charge effects on ionic transport, as indicated by chloride diffusion experiments and electrophoric tests using zeta potential measurements. Indeed, 36Cl− was strongly more hindered than water, when diffused in reacted materials, with a diffusivity decrease by a factor of 450 in chalk and a total restriction of 36Cl− in kaolinite. These experiments clearly provide an insight of how local pore structure properties combined with mineral reactivity could help in predicting the evolution of pore scale clogging and its impact on water and ionic diffusive transport.
Databáze: OpenAIRE
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