An extended macroscopic model for solute dispersion in confined porous media

Hamdan, E.; Milthorpe, J. F.; Lai, J.C.S.

doi:10.1016/j.cej.2007.05.031

Cited by 14 publications

(7 citation statements)

References 63 publications

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“…Interesting generalizations of this procedure may be found in Berentsen and Kruijsdijk (2008) and Hamdan et al (2008). The situation has some similarity with that found in Chap.…”

Section: ) Penetration Length (L)supporting

confidence: 65%

“…However, the direct study of the intermediate time scales turns out to be very complicated and clever simplifications are useful for practical aims (Camacho 1993a, b, c;Berentsen et al 2005;Berentsen and Kruijsdijk 2008;Hamdan et al 2008). However, the direct study of the intermediate time scales turns out to be very complicated and clever simplifications are useful for practical aims (Camacho 1993a, b, c;Berentsen et al 2005;Berentsen and Kruijsdijk 2008;Hamdan et al 2008).…”

Section: Taylor Dispersion and Microfluidicsmentioning

confidence: 99%

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Thermodynamics of Fluids Under Flow

Jou

Casas-Vázquez

Criado-Sancho

2011

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“…Interesting generalizations of this procedure may be found in Berentsen and Kruijsdijk (2008) and Hamdan et al (2008). The situation has some similarity with that found in Chap.…”

Section: ) Penetration Length (L)supporting

confidence: 65%

Section: Taylor Dispersion and Microfluidicsmentioning

confidence: 99%

Thermodynamics of Fluids Under Flow

Jou

Casas-Vázquez

Criado-Sancho

2011

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“…Under these conditions, the transient longitudinal dispersion coefficient at a given velocity reaches its asymptotic (long-time) limit and becomes constant [50], i.e., full lateral equilibration of analytes between all scales of flow heterogeneities over the column cross-section can be assumed. A detailed physicochemical characterization of the hydrodynamics in the packings is realized with the Giddings equation [51].…”

Section: Resultsmentioning

confidence: 99%

Bed morphological features associated with an optimal slurry concentration for reproducible preparation of efficient capillary ultrahigh pressure liquid chromatography columns

Reising

Godinho

Jorgenson

et al. 2017

Journal of Chromatography A

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Column wall effects and the formation of larger voids in the bed during column packing are factors limiting the achievement of highly efficient columns. Systematic variation of packing conditions, combined with three-dimensional bed reconstruction and detailed morphological analysis of column beds, provide valuable insights into the packing process. Here, we study a set of sixteen 75 µm i.d. fused-silica capillary columns packed with 1.9 µm, C18-modified, bridged-ethyl hybrid silica particles slurried in acetone to concentrations ranging from 5 to 200 mg/mL. Bed reconstructions for three of these columns (representing low, optimal, and high slurry concentrations), based on confocal laser scanning microscopy, reveal morphological features associated with the implemented slurry concentration, that lead to differences in column efficiency. At a low slurry concentration, the bed microstructure includes systematic radial heterogeneities such as particle size-segregation and local deviations from bulk packing density near the wall. These effects are suppressed (or at least reduced) with higher slurry concentrations. Concomitantly, larger voids (relative to the mean particle diameter) begin to form in the packing and increase in size and number with the slurry concentration. The most efficient columns are packed at slurry concentrations that balance these counteracting effects. Videos are taken at low and high slurry concentration to elucidate the bed formation process. At low slurry concentrations, particles arrive and settle individually, allowing for rearrangements. At high slurry concentrations, they arrive and pack as large patches (reflecting particle aggregation in the slurry). These processes are discussed with respect to column packing, chromatographic performance, and bed microstructure to help reinforce general trends previously described. Conclusions based on this comprehensive analysis guide us towards further improvement of the packing process.

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“…Analogous closure models have been extensively employed in dealing with environmental transport in rivers, estuaries, etc. For the mean concentration of solute in confined porous media, Hamdan et al [25] even presented an extended high-order model, though with complexity beyond reach of practical applications for the time being. Similar operation of average to yield Taylor dispersion is found in studies of a packed bed associated with groundwater pollution and chemical engineering [7,26].…”

Section: Environmental Dispersionmentioning

confidence: 98%

Environmental dispersivity in free-water-surface-effect dominated wetland: multi-scale analysis

Zeng

et al. 2011

Front. Environ. Sci. Eng. China

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Distinct from the case with width-dominated shallow wetland flows, the longitudinal evolution of contaminant concentration in the most-typical pattern of wetland as dominated by free-water-surface-effect is characterized by a multi-scale analysis in the present study. An environmental dispersion model for the evolution of the mean concentration is deduced as an extension of Taylor's classical formulation by Mei's multi-scale analysis. Corresponding environmental dispersivity is found identical to that determined by the method of concentration moments.

show abstract

An extended macroscopic model for solute dispersion in confined porous media

Cited by 14 publications

References 63 publications

Thermodynamics of Fluids Under Flow

Thermodynamics of Fluids Under Flow

Bed morphological features associated with an optimal slurry concentration for reproducible preparation of efficient capillary ultrahigh pressure liquid chromatography columns

Environmental dispersivity in free-water-surface-effect dominated wetland: multi-scale analysis

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