Role of pH in Electro-Osmosis: Experimental Study on NaCl–Water Saturated Kaolinite

Beddiar, Karim; Fen‐Chong, Teddy; Dupas, A.; Berthaud, Yves; Dangla, Patrick

doi:10.1007/s11242-004-6798-9

Cited by 36 publications

(9 citation statements)

References 15 publications

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“…In order to illustrate the potential of the three-scale computational model in simulating electroosmotic flows, the resultant discrete system is applied to numerically simulate the one-dimensional transient electroosmosis experiment for desalination of a kaolinite sample (Beddiar et al 2005;Finno et al 1996). The clay occupies the domain = [0, L] and is initially filled with an aqueous solution of concentrations C 0 Nab + and C 0 Hb + .…”

Section: Application To the Electroosmosis Experimentsmentioning

confidence: 99%

“…At t = 0, an electric field is applied due to the placement of anode and cathode at the boundaries x = 0 and x = L, respectively. For simplicity, we consider pH-controlled conditions at the electrodes in the sense of Beddiar et al (2005) and also postulate electric potential, pressure, and sodium concentration given on the boundary prescribed through the enforcement Dirichlet boundary conditions (see Lima et al (2008) and Fig. 14).…”

Section: Application To the Electroosmosis Experimentsmentioning

confidence: 99%

“…The three-scale model is discretized by the finite volume method (Patankar 1980) and applied to numerically simulate a transient electroosmosis experiment of desalination of a kaolinite sample (Beddiar et al 2005;Finno et al 1996). The evolution of the macroscopic profiles of pressure, electric potential, salinity, acidity, ζ -potential, and surface charge are presented for different boundary conditions.…”

Section: Introductionmentioning

confidence: 99%

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A Three-Scale Model of pH-Dependent Flows and Ion Transport with Equilibrium Adsorption in Kaolinite Clays: II Effective-Medium Behavior

et al. 2010

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In part I (Lima et al., Transp Porous Media, 2009), a three-scale model governing the movement of an aqueous saline solution containing four monovalent species (Na + , H + , Cl − , OH − ) in kaolinite clays was derived. Unlike purely macroscopic approaches, the novelty of the formulation relied on the double averaging of the nanoscopic electrochemistry of particle/electrolyte solution interface ruled by the electrical double layer coupled with protonation/deprotonation reactions. The passage from the nano to the micro (pore)-scale gave rise to ion-sorbed concentrations and slip velocity at the solid/fluid interface which are coupled with the microscopic Stokes problem and Nernst-Planck equations governing the hydrodynamics and ion transport in the micropores. Application of a formal homogenization procedure led to macroscopic governing equations with effective electro-chemical parameters, such as retardation coefficients, electro-osmotic permeability, and electric conductivity. In this study, we reconstruct the constitutive laws of the macroscopic coefficients by solving the nano and microscopic closure problems. New generalized isotherms for Na + and H + − OH − sorption are build-up based on a perturbation approach and the limitations 123 46 S. A. de Lima et al. of classical Freundlich isotherm for modeling ion sorption at the solid/fluid interface are discussed. The macroscopic governing equations are discretized by the finite volume method and numerical simulations of a transient electroosmosis experiment for desalination of a clay sample by electrokinetics are presented. List of Symbolsa fs Surface area [m −1 ] f Characteristic function m, n, p Exponents of the adsorption isotherms k e Isoelectric point p Thermodynamic pressure [Pa] t Time [s] x, y Parallel and orthogonal coordinates [m] u Auxiliary perturbation parameter C ib Ionic bulk concentration with i = Na,H [mol/m 3 ] C H + 0 H + concentration at the solid surface [mol/l] C b Bulk concentration [mol/m 3 ] F Faraday constant [C/mol] H Half distance between the particles [m] K Equilibrium constant [l/mol] K W Ionic product of water [(mol/l) 2 ] L D Debye's length [m] L Sample length [m] M Metallic ions at the surface R ideal gas constant [J/(mol K)] R N , R H Ionic retardation coefficients T Temperature [K] Y Cell domain Y f , Y s Fluid and solid subdomains ∂Y fs Fluid/solid interface x Macroscopic coordinate [m] y Microscopic coordinate [m] A eff First Onsager coefficient [(C·m 2 )/(mol·s)] B eff Second Onsager coefficient [(C·m 2 )/(mol·s)] C eff Effective electric conductivity [C/(m·s)] D eff Net effective diffusivity H + -OH + [m 2 /s] D eff Na Effective sodium diffusivity [m 2 /s] K eff P Hydraulic conductivity [m 2 /(Pa·s)] K eff E Electroosmotic permeability [m/(V·s)] I eff f Effective electric current [C/(m 2 ·s)] J eff Effective ionic flux [mol/(m 2 ·s)] 123 A Three-Scale Model of Ion Transport with Equilibrium Adsorption in 1:1 Clays 47

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Section: Application To the Electroosmosis Experimentsmentioning

confidence: 99%

Section: Application To the Electroosmosis Experimentsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Three-Scale Model of pH-Dependent Flows and Ion Transport with Equilibrium Adsorption in Kaolinite Clays: II Effective-Medium Behavior

et al. 2010

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“…No flow toward the anode was taking place. This is meant no changes in the sign of zeta potential of the soil occurred during the course of experiment [13] . Figure 5 also shows the cumulative electroosmotic flows as a function of the time under various applied electric voltages in the tested peat.…”

Section: Electroosmosis Experimentsmentioning

confidence: 99%

“…It can be explained by electrolysis of water at the anode and the cathode [14] . Electrolysis of water produces oxygen and hydrogen which can be represented by the following equations:…”

Section: Electroosmosis Experimentsmentioning

confidence: 99%

Electroosmotic Phenomena in Organic Soils

Asadi¹,

Huat²,

Hassim³

et al. 2009

American J. of Environmental Sciences

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Organic soils or peat represent an accumulation of disintegrated plant remains which have been preserved under condition of incomplete aeration and high water content. In order to develop a fundamental understanding of electroosmotic phenomena in peat, initially microelectrophoresis studies were carried out to conceptualize the electrokinetic phenomena. Then electroosmosis experiments were conducted on rigid cube samples containing 0.0001 M NaCl-water saturated peat. The openanode and open-cathode systems were employed to the soil samples. Distilled Water (DW) were used as anolyte and catholyte. The experiments were carried out via applications of diffrent DC electrical potentials. The results of microelectrophoresis study showed changes of zeta potential due to the effect of HCl and NaOH. The correlations between zeta potential and pH were found. The negative charge of peat is high pH dependent and the surface charge was dropped to zero at pH around 3. The high degree of decomposition resulted in the higher zeta potential in peat. It was also experimentally found that the electroosmotic flow in peat is feasible. The direction of electroosmotic flows were from the anode to cathode.

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Improvement of the Mechanical Properties of P300 Kaolinite Using MICP in the Low Water Content Range

Maston,

Ouahbi,

Dadda

et al. 2023

RILEM Bookseries

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Role of pH in Electro-Osmosis: Experimental Study on NaCl–Water Saturated Kaolinite

Cited by 36 publications

References 15 publications

A Three-Scale Model of pH-Dependent Flows and Ion Transport with Equilibrium Adsorption in Kaolinite Clays: II Effective-Medium Behavior

A Three-Scale Model of pH-Dependent Flows and Ion Transport with Equilibrium Adsorption in Kaolinite Clays: II Effective-Medium Behavior

Electroosmotic Phenomena in Organic Soils

Improvement of the Mechanical Properties of P300 Kaolinite Using MICP in the Low Water Content Range

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