The influence of small pores on the anion transport properties of natural argillaceous rocks – A pore size distribution investigation of Opalinus Clay and Helvetic Marl

Wigger, Cornelia; Gimmi, Thomas; Müller, Arnaud; Loon, Luc R. Van

doi:10.1016/j.clay.2018.01.032

Cited by 12 publications

(5 citation statements)

References 58 publications

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“…Yet, it is not clear for organic anions, which parts of exclusion are due to charge effect and steric effect. In addition to charge exclusion, larger molecule may be more excluded from porosity, due to the presence of small porosity in clay rich media (Gaboreau et al, 2016;Wigger and Van Loon, 2018). Such hypothesis seems confirmed by the correlation between ∏ and molecule size (Fig.…”

Section: Origin Of Exclusion From the Porositymentioning

confidence: 58%

Diffusion of organic anions in clay-rich media: Retardation and effect of anion exclusion

et al. 2018

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The transport of emerging organic contaminants through the geosphere is often an environmental issue. The sorption of organic compounds slows their transport in soils and porous rocks and retardation is often assessed by extrapolation of batch experiments. However, transport experiments are preferable to strengthen migration data and modelling. In this context, we evaluated the adsorption of various organic acids by means of through-diffusion experiments in a sedimentary clay-rich rock (Callovo-Oxfordian, East of Paris Basin, France). A low diffusivity of organic anions was quantified with effective diffusion coefficients, D, ranged between 0.5 and 7 10 m s. These values indicated an organic anion exclusion. As for chloride, the porosity accessible to organic anions was lower than that of water: ε(organic anions) < ε(water). The partial exclusion of organic anions from rock porosity was linked to both charge and size effects. A significant retardation was observed for organic anions such as oxalate, citrate or α-isosaccharinate. Yet, retardation measured by diffusion experiments was significantly lower than expected from batch experiments on crushed samples. An empirical correction factor is proposed to account for a possible decrease of retardation with accessible porosity of diffusing solute. This feature has significant implications for the estimation of migration parameters of organic compounds in the environment.

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Section: Origin Of Exclusion From the Porositymentioning

confidence: 58%

Diffusion of organic anions in clay-rich media: Retardation and effect of anion exclusion

et al. 2018

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“…Π(anion) << Π(water) = 1). This phenomena is usually explained by the presence of surface charged clay minerals (Tournassat et al, 2016) and more pronounced when pore size is small (Gaboreau, et al, 2016;Wigger et al, 2018). For example, a strong anion exclusion is observed in COx clay units (UA2, UA3, <-450 m in depth), quantified with Π(Cl -/COx) ~ 0.3 ± 0.1 (Descostes et al, 2008).…”

Section: Diffusion Data and Exclusion From Rock Porositymentioning

confidence: 99%

Mobility of organic compounds in a soft clay-rich rock (Tégulines clay, France)

et al. 2021

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“…Clay-rich rocks have high surface areas and complex pore structures controlled by the microstructure and aggregation of the clays. Pore sizes and shapes vary across a range of dimensions and scales from nanometer-sized to larger micron-sized pores between clay aggregates 1 , 2 . Although there is significant research on the bulk porosity of meteorites 3 – 6 , the surface area and bulk submicron-scale porosity in the carbonaceous chondrite (CC) meteorites are relatively understudied.…”

Section: Introductionmentioning

confidence: 99%

High surface area and interconnected nanoporosity of clay-rich astromaterials

Garvie,

Trif,

Cotto-Figueroa

et al. 2024

Sci Rep

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Porosity affects key astromaterial processes from disruption in our atmosphere and impact with the ground, to the comminution of boulders by thermal and impact processes and slope mechanics on asteroid surfaces, to access and utilization of in-situ resources. Whereas the bulk porosity of clay-rich meteorites is well established, the magnitude of their surface area and nano-scale porosity is poorly known. Here we use N2 BET gas adsorption to measure the specific surface area and nanoscale pore distribution in several clay-rich meteorites. Two recent falls Tarda (C2-ung) and Aguas Zarcas (CM2) have specific surface areas of 72.5 and 16.5 m2/g, respectively. However, the specific surface area of Tarda ranges from 33.7 to 81.6 m2/g depending on outgassing conditions. The Tarda surface area is dominated by an interconnected network of ~ 3-nm-sized pores, whereas Aguas Zarcas shows a lower density of ~ 3 nm pores and broader size distribution around 40 nm. In contrast, Ivuna and Orgueil (CI1) have surface areas of ~ 15 to 18 m2/g: the low values compared to Tarda are likely due to the neoformation of pore-blocking minerals during atmospheric exposure. These data suggest that returned samples from asteroids Ryugu and Bennu, which are mineralogically and texturally similar to Tarda, also have interconnected nano-scale porosity with high surface area.

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The influence of small pores on the anion transport properties of natural argillaceous rocks – A pore size distribution investigation of Opalinus Clay and Helvetic Marl

Cited by 12 publications

References 58 publications

Diffusion of organic anions in clay-rich media: Retardation and effect of anion exclusion

Diffusion of organic anions in clay-rich media: Retardation and effect of anion exclusion

Mobility of organic compounds in a soft clay-rich rock (Tégulines clay, France)

High surface area and interconnected nanoporosity of clay-rich astromaterials

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