Diffusion of 1-naphthol and naphthalene through clay materials: Measurement of apparent exclusion of solute from the pore space

Sawatsky, N.; Feng, Yongsheng; Dudas, M. J.

doi:10.1016/s0169-7722(96)00027-7

Cited by 16 publications

(9 citation statements)

References 20 publications

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“…The close correspondence between the column-derived retardation factors and the Kd-derived factors implies that the sorption capacities of the aquitard material in these columns are the same whether dispersed in a batch system or packed into a column; that is, for this material, solute is not excluded from potential sorption regions due to packing, as was proposed by Sawatsky et al ( 4) for a subsurface material containing 43% clay (80% of which was montmorillonite), 48% silt, and 9% sand. We note that our material had no detectable montmorillonite, which is in contrast with the material of Sawatsky et al (4). We are uncertain whether the high content of swelling clay is a significant factor in the results of Sawatsky et al (4).…”

Section: Resultscontrasting

confidence: 63%

Estimating Diffusion Coefficients in Low-Permeability Porous Media Using a Macropore Column

Young

Ball

1998

Environ. Sci. Technol.

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Diffusion coefficients in an aquitard material were measured by conducting miscible solute transport experiments through a specially constructed macropore column. Stainless steel HPLC columns were prepared in a manner that created an annular region of repacked aquitard material and a central core of medium-grained quartz sand. The column transport approach minimizes volatilization and sorption losses that can be problematic when measuring hydrophobic organic chemical diffusion with diffusion-cell methods or column-sectioning techniques. In the transport experiments, solutes (tritiated water, 1,2,4trichlorobenzene, and tetrachloroethene) were transported through the central core by convection and hydrodynamic dispersion and through the low-permeability annulus by radial diffusion. All transport parameters were independently measured except for the effective diffusion coefficient in the aquitard material, which was obtained by model fitting. Batch-determined retardation factors agreed very closely with moment-derived retardation factors determined from the column experiments, and no evidence of pore exclusion was found. A model with retarded diffusion was found to apply, and the effective tortuosity factor of the aquitard material was estimated at an average value of 5.1 (based on estimates that ranged from 3.7 to 7.7).

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Section: Resultscontrasting

confidence: 63%

Estimating Diffusion Coefficients in Low-Permeability Porous Media Using a Macropore Column

Young

Ball

1998

Environ. Sci. Technol.

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“…Diffusion is an important process controlling grain‐scale sorption and desorption kinetics [ Ball and Roberts , 1991; Cunningham et al , 1997; Ewing et al , 2010; Grathwohl , 1998; Miller and Pedit , 1992; Werth et al , 1997; Wood et al , 1990], porescale reactive transport [ Kang et al , 2007; Li et al , 2006, 2008; Tartakovsky et al , 2007], and mass transfer in low‐permeability zones and rock matrix [ Ball et al , 1997; Brusseau , 1991; Liu and Ball , 2002; Parker et al , 2004; Sawatsky et al , 1997; Steefel and Litchner , 1994; Tokunaga et al , 2001; Tokunaga et al , 2004] in subsurface environments. Diffusion of a multispecies contaminant, such as uranyl [U(VI)], is affected in complex ways by various factors including aqueous/surface speciation and solution chemical composition [ Felmy and Weare , 1991; Lasaga , 1981; Miller , 1967a; Van Cappellen and Gaillard , 1996], and species and mineral surface charges and electrostatic potential [ Appelo and Wersin , 2007; Hart et al , 2001; Liu et al , 2004; Liu , 2007; Malusis and Shackelford , 2002; Nomura and Sakata , 2001].…”

Section: Introductionmentioning

confidence: 99%

Multispecies diffusion models: A study of uranyl species diffusion

Liu¹,

Shang²,

Zachara³

2011

Water Resources Research

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[1] Rigorous numerical description of multispecies diffusion requires coupling of species, charge, and aqueous and surface complexation reactions that collectively affect diffusive fluxes. The applicability of a fully coupled diffusion model is, however, often constrained by the availability of species self-diffusion coefficients, as well as by computational complication in imposing charge conservation. In this study, several diffusion models with variable complexity in charge and species coupling were formulated and compared to describe reactive multispecies diffusion in groundwater. Diffusion of uranyl [U(VI)] species was used as an example in demonstrating the effectiveness of the models in describing multispecies diffusion. Numerical simulations found that a diffusion model with a single, common diffusion coefficient for all species was sufficient to describe multispecies U(VI) diffusion under a steady state condition of major chemical composition, but not under transient chemical conditions. Simulations revealed that for multispecies U(VI) diffusion under transient chemical conditions, a fully coupled diffusion model could be well approximated by a component-based diffusion model when the diffusion coefficient for each chemical component was properly selected. The component-based diffusion model considers the difference in diffusion coefficients between chemical components, but not between the species within each chemical component. This treatment significantly enhanced computational efficiency at the expense of minor charge conservation. The charge balance in the component-based diffusion model can be enforced, if necessary, by adding a secondary migration term resulting from model simplification. The effect of ion activity coefficient gradients on multispecies diffusion is also discussed. The diffusion models were applied to describe U(VI) diffusive mass transfer in intragranular domains in two sediments collected from U.S. Department of Energy's Hanford 300A, where intragranular diffusion is a rate-limiting process controlling U(VI) adsorption and desorption. The grain-scale reactive diffusion model was able to describe U(VI) adsorption/desorption kinetics that had been previously described using a semiempirical, multirate model. Compared with the multirate model, the diffusion models have the advantage to provide spatiotemporal speciation evolution within the diffusion domains.Citation: Liu, C., J. Shang, and J. M. Zachara (2011), Multispecies diffusion models: A study of uranyl species diffusion, Water Resour.

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“…In soils where advection is minimal, diffusion may be the dominant mode of solute transport (e.g. Sawatsky et al, 1997); hence, quantification of solute diffusion maybe critical. Diffusion may also have a strong influence on solute concentration within mobile pores in a dual porosity medium or in soil of low permeability containing fractures or macropores.…”

Section: Introductionmentioning

confidence: 99%

Studies of solute transport through fractured till in Iowa

Helmke

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Diffusion of 1-naphthol and naphthalene through clay materials: Measurement of apparent exclusion of solute from the pore space

Cited by 16 publications

References 20 publications

Estimating Diffusion Coefficients in Low-Permeability Porous Media Using a Macropore Column

Estimating Diffusion Coefficients in Low-Permeability Porous Media Using a Macropore Column

Multispecies diffusion models: A study of uranyl species diffusion

Studies of solute transport through fractured till in Iowa

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