Electroosmotic Flow in Porous Media

A detailed analysis of the theories of electroosmotic flow in porous media was presented earlier [22] of the theories by Overbeek [23-25] and Dukhin and his co-workers [26-30], Overbeek extended von Smoluchowski s work to packed capillaries under conditions of low electric field strength. The model can be applied to porous or nonporous packing particles of any shape, and the particles can be assumed to be nonconducting, have uniform zeta potential, and a thin double layer. The average EOF velocity in a column for CEC can be expressed as... 

Electroosmosis in porous media Electroosmotic flow in porous media... 

Rathore AS, Horvath CS (1997) Capillary electrochromatography theories on electroosmotic flow in porous media. J Chromatogr A 781 185-195... 

U. TaDarek, E. Rapp, H. van As, E. Bayer, Using NMR displacement imaging to characterize electroosmotic flow in porous media. Magn. Reson. Imaging, 2001, 19, 453 56. 

Electrokinetic Flow in Porous Media, Figure 4 Electroosmotic flow velocity distributions in a charged microcapillary packed with charged microspheres, for different sizes of packing particles, dp. The results are obtained on the basis of (a) the numerical solution of Eg. (12) and (b) the analytical solution based on Eq. (27)... 

Electroklnetlc Flow in Porous Media, Figure 5 Electroosmotic flow rate versus applied electric field for different values of particle diameter, dp, and... 

After validation, the LPBM has been employed to simulate the electroosmotic flows in microgeometries. Besides the straight channel, complex geometries have also been considered, including a rough channel, porous arrays, and even random porous media. The simulation results are also compared with the existing experimental data. 

Wang M, Pan N, Wang JK, Chen SY (2007) Lattice Poisson-Boltzmann simulations of electroosmotic flows in charged anisotropic porous media. Commun Comput Phys 2(6) 1055-1070... 

In order to insure the sufficient efficiency of electrokinetic removal of multiple heavy metals from porous media, it is essential to understand the main parameters affecting the transport and electrokinetic phenomena. Such parameters can be summarized as (a) the theoretical ionic mobility related to the ionic valance and molecular diffusion coefficient of species, (b) the delaying or retardation effect caused by the affinity of heavy metals in solid matrix, and (c) the chemical forms of metal contaminants initially existing in soils. In addition, some unexpected effects especially brought about in the electrokinetic remediation of mixed metal contaminants should be considered. The electrokinetic remediation for mixed metal contaminants generally shows lower removal efficiency than that for individual metal contaminants. High concentrations of multiple metal contaminants can be related to other parameters, for example, transference number, zeta potential, electroosmotic flow, and so on, which are factors that should be taken into consideration with regard to the removal mechanisms. 

Since the ionic concentration has a great effect on the electric potential distribution in microchannels [13], we can model the flow rate versus the ionic concentration in an electroosmotic micropump packed by nanoscale charged porous media when E = I kV/m, AP = 0 Pa/m, jjp = —50 mV, and dp = 108 nm. 

Lattice Poisson-Boltzmann Method, Analysis of Electroosmotic Microfludics, Figure 18 Schematic illustration of electrokinetic flow in a microchannel packed with charged porous media. The A-A section crosses the centers of the cycles in the same section... 

Mention was made previously of the electroosmotic flow of water to the cathode encountered in electrophoresis in various stabilizing media. This phenomenon plays a relatively small role in free electrophoresis because of the small surface area in contact with the electrolyte solution in the U tube. However, it is a very familar subject to workers who deal with electrical forces in membranes and porous materials. The well-known streaming potential produced by forcing liquid under pressure through a porous medium is closely related to the electroosmotic flow. The potential of the surface to the liquid (f potential) can be determined by measurements of the volume (V) of liquid transported per second by electroosmosis, through the use of equation (1), where i denotes the current strength, k the specific... 

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