From random sphere packings to regular pillar arrays: Analysis of transverse dispersion

Daneyko, Anton; Hlushkou, Dzmitry; Khirevich, Siarhei; Tallarek, Ulrich

doi:10.1016/j.chroma.2012.08.024

Cited by 87 publications

(47 citation statements)

References 115 publications

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“…No theoretical basis exists for this limitation on minimum plate height. Transcolumn exchange of an analyte molecule on the 75 μm dimension of the capillary diameter is fast and any exchange between different regions of local flow velocity is quickly terminated by transverse dispersion [34]. Third, from past CLSM studies we know that the integral porosity deviation approaches zero as slurry concentration increases (indicative of wall region in a bed that attains average packing density as the bulk region of that bed) [17].…”

Section: Resultsmentioning

confidence: 99%

Implementation of high slurry concentration and sonication to pack high-efficiency, meter-long capillary ultrahigh pressure liquid chromatography columns

Godinho

Reising

Tallarek

et al. 2016

Journal of Chromatography A

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Slurry packing capillary columns for ultrahigh pressure liquid chromatography is complicated by many interdependent experimental variables. Previous results have suggested that combination of high slurry concentration and sonication during packing would create homogeneous bed microstructures and yield highly efficient capillary columns. Herein, the effect of sonication while packing very high slurry concentrations is presented. A series of six, 1 m × 75 μm internal diameter columns were packed with 200 mg/mL slurries of 2.02 μm bridged-ethyl hybrid silica particles. Three of the columns underwent sonication during packing and yielded highly efficient separations with reduced plate heights as low as 1.05.

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Section: Resultsmentioning

confidence: 99%

Implementation of high slurry concentration and sonication to pack high-efficiency, meter-long capillary ultrahigh pressure liquid chromatography columns

Godinho

Reising

Tallarek

et al. 2016

Journal of Chromatography A

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“…In recent years, the RWPT technique combined with the LBM was extensively used to study hydrodynamic dispersion in porous media [42,71,[74][75][76][77][78][79][80][81][82][83][84]. The comparison with experimental data confirmed that this approach allows to determine longitudinal and transverse dispersion coefficients with high accuracy [84].…”

Section: Lattice-boltzmann and Random-walk Particle-tracking Methodsmentioning

confidence: 94%

Impact of diffusion on transverse dispersion in two-dimensional ordered and random porous media

2017

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Solute dispersion in fluid flow results from the interaction between advection and diffusion. The relative contributions of these two mechanisms to mass transport are characterized by the reduced velocity ν, also referred to as the Péclet number. In the absence of diffusion (i.e., when the solute diffusion coefficient D_{m}=0 and ν→∞), divergence-free laminar flow of an incompressible fluid results in a zero-transverse dispersion coefficient (D_{T}=0), both in ordered and random two-dimensional porous media. We demonstrate by numerical simulations that a more realistic realization of the condition ν→∞ using D_{m}≠0 and letting the fluid flow velocity approach infinity leads to completely different results for ordered and random two-dimensional porous media. With increasing reduced velocity, D_{T} approaches an asymptotic value in ordered two-dimensional porous media but grows linearly in disordered (random) structures depending on the geometrical disorder of a structure: a higher degree of heterogeneity results in a stronger growth of D_{T} with ν. The obtained results reveal that disorder in the geometrical structure of a two-dimensional porous medium leads to a growth of D_{T} with ν even in a uniform pore-scale advection field; however, lateral diffusion is a prerequisite for this growth. By contrast, in ordered two-dimensional porous media the presence of lateral diffusion leads to a plateau for the transverse dispersion coefficient with increasing ν.

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“…Since diffusion on this length scale will be obstructed by the spheres of the packing and their shells, it is reasonable to use the effective diffusion coefficient D eff instead of the molecular diffusion coefficient D m in the diffusion-controlled contribution described by Eq. (31). This modification has been previously proposed in [5].…”

Section: Eddy-dispersion Formula For Core-shell Particlesmentioning

confidence: 86%

“…Finally, the transport of point-like tracers in the interparticle void space and porous shells of the packing particles was modeled by a random-walk particle-tracking (RWPT) technique. A similar simulation approach was previously applied to study the effect of packing porosity, morphology, and particle size distribution on effective diffusivity and eddy dispersion in packed beds [25,[27][28][29][30][31]; to analyze the impact of the packing confinement on eddy dispersion [32,33]; to study hydrodynamic dispersion in silica and polymeric chromatographic monoliths [34][35][36][37][38]; and to investigate the influence of analyte retention and adsorption kinetics on mass transport in open channels and packed beds [39][40][41]. In this study, we mainly focus on the analysis of the influence of two core-shell particle characteristics -the shell thickness and the value of the effective diffusion coefficient in the shell -on the plate height.…”

Section: Introductionmentioning

confidence: 98%

Computational investigation of longitudinal diffusion, eddy dispersion, and trans-particle mass transfer in bulk, random packings of core–shell particles with varied shell thickness and shell diffusion coefficient

Daneyko

Hlushkou

Baranau

et al. 2015

Journal of Chromatography A

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From random sphere packings to regular pillar arrays: Analysis of transverse dispersion

Cited by 87 publications

References 115 publications

Implementation of high slurry concentration and sonication to pack high-efficiency, meter-long capillary ultrahigh pressure liquid chromatography columns

Implementation of high slurry concentration and sonication to pack high-efficiency, meter-long capillary ultrahigh pressure liquid chromatography columns

Impact of diffusion on transverse dispersion in two-dimensional ordered and random porous media

Computational investigation of longitudinal diffusion, eddy dispersion, and trans-particle mass transfer in bulk, random packings of core–shell particles with varied shell thickness and shell diffusion coefficient

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