Analysis of the salt retention of a titania membrane using the “DSPM” model: effect of pH, salt concentration and nature

Labbez, Christophe; Fiévet, P.; Szymczyk, Anthony; Vidonne, A.; Foissy, A.; Pagetti, J.

doi:10.1016/s0376-7388(02)00310-1

Cited by 117 publications

(98 citation statements)

References 15 publications

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“…Since inorganic salts such as KCl, K2SO4, MgCl2, and MgSO4 are not adsorbed onto titania at the neutral pH region, 19 those salts on titania could be efficiently eliminated by washing with 10 ml of water. The conductivity of the resulting solution was lowered by 24.7 μS/cm, which was close to the value of 19.7 μS/cm for a test sample prepared using pure water.…”

Section: Methods Validationmentioning

confidence: 99%

Absolute Determination Method for Trace Quantities of Enantiomer of Glufosinate by 7-Cyclodextrin Modified Capillary Zone Electrophoresis Combined with Solid-Phase Extraction and On-capillary Concentration

Asami

Imura

2006

ANAL. SCI.

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A highly sensitive and accurate determination method for trace quantities of enantiomers of glufosinate (D,L-GLUF), a phosphorus-containing amino acid-type herbicide, has been studied. The present method is based on the change in the mole ratio of the enantiomeric isomers after spiking of a known amount of an isomer (L-GLUF). The chiral separation and detection were made by γ-cyclodextrin modified capillary zone electrophoresis (γ-CD-CZE) with fluorescence detection. Solid-phase extraction of D,L-GLUF with titania was investigated as the pre-separation method to eliminate coexisting materials such as inorganic salts and organic compounds in river water. A separated D,L-GLUF was labeled with dansyl chloride and subjected to the on-capillary concentration using large-volume sample stacking (LVSS) before γ-CD-CZE. The detection limit of the present method was as low as 2.0 × 10 -9 M. The present method was successfully applied to a model sample containing 2.0 × 10 -7 M D,L-GLUF in river water. It was confirmed that trace quantities of Dand L-GLUF in environmental samples can be accurately determined without any calibration curves and comparison standards.

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Section: Methods Validationmentioning

confidence: 99%

Absolute Determination Method for Trace Quantities of Enantiomer of Glufosinate by 7-Cyclodextrin Modified Capillary Zone Electrophoresis Combined with Solid-Phase Extraction and On-capillary Concentration

Asami

Imura

2006

ANAL. SCI.

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“…Since the potential in the right reservoir is not known in advance and should be determined from the solution of the problem, it is not possible to specify the distribution of potential in the nanopore and reservoirs in the form similar to (15). In the frame of homogeneous approach, we assume that the potential in the nanopore is the function of z only, so…”

Section: One-dimensional Model With Specified Surface Potentialmentioning

confidence: 99%

“…The difference between curves obtained from one-and two-dimensional models is observed in a short region of around 10 nm near z = 0 and z = L p , while outside this region the curves virtually coincide. The difference is caused by the geometry of reservoirs and the value of constant k in formula (15).…”

Section: The Distributions Of Potential Pressure Ion Concentrationsmentioning

confidence: 99%

“…The Donnan-steric partitioning pore model (DSPM) [12] takes into account the finite ion size by introducing diffusive and convective hindrance factors. The fitting of experimental rejection data to this model allowed obtaining such membrane characteristics as pore radius, volume charge density, and effective membrane thickness [13][14][15]. The effect of concentration polarization on salt rejection was investigated in [16] by coupling the DSPM model with convection-diffusion equations in the boundary layer adjacent to the membrane.…”

Section: Introductionmentioning

confidence: 99%

“…Note that we do not take into account the hindrance factors for convection and diffusion [13][14][15] since our aim is to compare the results obtained from one-and two-dimensional models. The latter model is described in Section 2.3 and does not take into account the hindrance effects in the present formulation.…”

Section: Introductionmentioning

confidence: 99%

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Theoretical study of electrolyte transport in nanofiltration membranes with constant surface potential/charge density

Ryzhkov

Минаков

2016

Journal of Membrane Science

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Abstract. The pressure-driven ion transport through nanofiltration membrane pores with constant surface potential or charge density is investigated theoretically. Two approaches are employed in the study. The first one is based on one-dimensional Nernst-Planck equation coupled with electroneutrality, zero current, and Donnan equilibrium conditions. This model is extended to account for interfacial effects by using a smooth approximation of step function for the volume charge density. A simplified model for the case of constant surface potential is also proposed. The second approach is based on two-dimensional Nernst-Planck, Poisson, and Navier-Stokes equations, which are solved in a high aspect ratio nanopore connecting two reservoirs with much larger diameter. The modification of equations on the basis of Slotboom transformation is employed to speed up the convergence rate. The distributions of potential, pressure, ion concentrations and fluxes due to convection, diffusion, and migration in the nanopore and reservoirs are discussed and analyzed. It is found that for constant surface charge density, the convective flux of counter-ions in the nanopore is almost completely balanced by the opposite migration flux, while for constant surface potential, the convective flux is balanced by the opposite diffusion and migration fluxes. The co-ions in the nanopore are mainly transported by diffusion. A particular attention is focused on describing the interfacial effects at the nanopore entrance/exit. Detailed comparison between one-and two-dimensional models is performed in terms of rejection, pressure drop, and membrane potential dependence on the surface potential/charge density, volume flux, electrolyte concentration, and pore radius. A good agreement between these models is found when the Debye length is smaller than the pore radius and the surface potential or charge density are sufficiently low.

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Mechanistic Modeling of Transport in Nanofiltration

Szymczyk¹

2013

Encyclopedia of Membrane Science and Technology

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This article discusses macroscopic modeling of the transport mechanisms of ions through nanofiltration membranes. The modeling is based on mechanistic approaches that consider nanofiltration membranes as bundles of (nano)pores and ionic transport as resulting from hindered diffusion, electromigration, and convection. The governing equations are presented and the main assumptions and approximations are reviewed and discussed. Special attention is given to the uniform potential approximation (also called homogeneous approximation ), which forms the basis of most current transport models used in nanofiltration. The impact of steric hindrance, membrane fixed charge density, and salt concentration on the rejection of single‐salt solutions and electrolyte mixtures is illustrated through a series of examples. Some recent advances in nanofiltration modeling (introduction into transport models of the dielectric exclusion phenomena and spatial inhomogeneities of the fixed charge) are also briefly discussed.

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Analysis of the salt retention of a titania membrane using the “DSPM” model: effect of pH, salt concentration and nature

Cited by 117 publications

References 15 publications

Absolute Determination Method for Trace Quantities of Enantiomer of Glufosinate by 7-Cyclodextrin Modified Capillary Zone Electrophoresis Combined with Solid-Phase Extraction and On-capillary Concentration

Absolute Determination Method for Trace Quantities of Enantiomer of Glufosinate by 7-Cyclodextrin Modified Capillary Zone Electrophoresis Combined with Solid-Phase Extraction and On-capillary Concentration

Theoretical study of electrolyte transport in nanofiltration membranes with constant surface potential/charge density

Mechanistic Modeling of Transport in Nanofiltration

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