Simulation of concentration polarization in electrokinetic processes by network thermodynamic methods

Horno, J.; González-Fernández, C.F.; Hayas, A.; González‐Caballero, F.

doi:10.1016/s0006-3495(89)82846-2

Cited by 23 publications

(14 citation statements)

References 17 publications

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“…9 shows the complete equivalent circuit representation of PRO across a semi‐permeable membrane. Equivalent circuit representations have been proposed for membrane‐based processes, but this is the first for PRO [29, 30].…”

Section: Effects Of Spatial Variations On Powermentioning

confidence: 99%

Introduction to PRO for energy conversion applications including an electric equivalent circuit

Maisonneuve

Pillay

2016

IET Renewable Power Generation

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Pressure retarded osmosis (PRO) is a renewable energy conversion process with potential for sustainable power production. This study introduces this resource to the electrical engineering community and presents the first electric equivalent circuit of the process. This provides a useful tool for integrated osmotic power plant analysis and design. The model illustrates the influence of several important non‐ideal effects on power output including concentration polarisation, spatial variation, and pressure drop. The dynamic influence of salt storage by water is also considered. The influence of feed and draw input currents and hydraulic load on power output are investigated and suggest that there is some operating point that will yield maximum power. This illustrates the need for maximum power point tracking in PRO energy conversion.

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Section: Effects Of Spatial Variations On Powermentioning

confidence: 99%

Introduction to PRO for energy conversion applications including an electric equivalent circuit

Maisonneuve

Pillay

2016

IET Renewable Power Generation

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“…Studies of nanocomposite membranes of bacterial cellulose reveal interesting new properties of these materials and their applications [ 13 – 15 ]. In case of membranes and membrane dressings, concentration polarization is an important phenomenon significantly limiting the transport of volumes and solutes through the membranes, influencing solute fluxes through the membrane [ 16 , 17 ] as well as the measured voltages and currents through the membrane in the case of transport of electrolyte solutions [ 18 – 21 ]. A characteristic feature of concentration polarization is concentration boundary layers (CBLs) [ 16 , 22 , 23 ] with concentration profiles dependent on the initial conditions [ 16 , 24 ], type of solute, properties of the membrane itself, and the membrane orientation in relation to the direction of the gravitational field vector [ 22 , 25 – 27 ].…”

Section: Introductionmentioning

confidence: 99%

“…A characteristic feature of concentration polarization is concentration boundary layers (CBLs) [ 16 , 22 , 23 ] with concentration profiles dependent on the initial conditions [ 16 , 24 ], type of solute, properties of the membrane itself, and the membrane orientation in relation to the direction of the gravitational field vector [ 22 , 25 – 27 ]. In case of membranes arranged in a horizontal plane, diffusion and hydrodynamic instability of CBLs are the main phenomena that influence the CBL thickness [ 21 , 28 , 29 ] and can be visualized by interferometric methods [ 30 ]. Furthermore, the mechanical pressure difference (∆ P ) across the membrane and volume flux ( J v ) through the membrane cause changes in thickness of the CBLs [ 31 ] and distribution of solute near the membrane [ 32 ].…”

Section: Introductionmentioning

confidence: 99%

The role of mechanical pressure difference in the generation of membrane voltage under conditions of concentration polarization

Grzegorczyn

Ślęzak

2016

J Biol Phys

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The mechanical pressure difference across the bacterial cellulose membrane located in a horizontal plane causes asymmetry of voltage measured between electrodes immersed in KCl solutions symmetrically on both sides of the membrane. For all measurements, KCl solution with lower concentration was above the membrane. In configuration of the analyzed membrane system, the concentration boundary layers (CBLs) are created only by molecular diffusion. The voltages measured in the membrane system in concentration polarization conditions were compared with suitable voltages obtained from the model of diffusion through CBLs and ion transport through the membrane. An increase of difference of mechanical pressure across the membrane directed as a difference of osmotic pressure always causes a decrease of voltage between the electrodes in the membrane system. In turn, for mechanical pressure difference across the membrane directed in an opposite direction to the difference of osmotic pressure, a peak in the voltage as a function of mechanical pressure difference is observed. An increase of osmotic pressure difference across the membrane at the initial moment causes an increase of the maximal value of the observed peak and a shift of this peak position in the direction of higher values of the mechanical pressure differences across the membrane.

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“…Ion Concentration Polarization (ICP) is a well known phenomenon [22] that is described by induced concentration gradient in systems where ion selectivity varies in the direction of transport. In the context of porous networks, ICP can occur when pores of varying cross sections are connected in series [23][24][25][26][27][28][29][30]33] or T-junctions [34][35][36][37] as well as in pore-membrane junctions [21,29,[38][39][40][41][42]. Wang et al [19] reported the use of ICP to generate high-focusing ratios of an ionic protein near a microchannel-nanochannel junction.…”

Section: Introductionmentioning

confidence: 99%

A multi-scale model for electrokinetic transport in networks of micro-scale and nano-scale pores

Alizadeh¹,

Mani²

2016

Preprint

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We present an efficient and robust numerical model for simulation of electrokinetic phenomena in porous networks over a wide range of applications including energy conversion, desalination, and lab-on-a-chip systems. Coupling between fluid flow and ion transport in these networks is governed by the Poisson-Nernst-Planck-Stokes equations. These equations describe a wide range of transport phenomena that can interact in complex and highly nonlinear ways in networks involving multiple pores with variable properties. Capturing these phenomena by direct simulation of the governing equations in multiple dimensions is prohibitively expensive. We present here a reduced order computational model that treats a network of many pores via solutions to 1D equations. Assuming that each pore in the network is long and thin, we derive a 1D model describing the transport in pore's longitudinal direction. We take into account the non-uniformity of potential and ion concentration profiles across the pore cross-section in the form of areaaveraged coefficients in different flux terms representing fluid flow, electric current, and ion fluxes. Distinct advantages of the present framework include: a fully conservative discretization, fully bounded tabulated area-averaged coefficients without any singularity in the limit of infinitely thick electric double layers (EDLs), a flux discretization that exactly preserves equilibrium conditions, and extension to general network of pores with multiple intersections. By considering a hierarchy of canonical problems with increasing complexity, we demonstrate that the developed framework can capture a wide range of phenomena. Example demonstrations include, prediction of osmotic pressure built up in thin pores subject to concentration gradient, propagation of deionization shocks and induced recirculations for intersecting pores with varying properties.

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Simulation of concentration polarization in electrokinetic processes by network thermodynamic methods

Cited by 23 publications

References 17 publications

Introduction to PRO for energy conversion applications including an electric equivalent circuit

Introduction to PRO for energy conversion applications including an electric equivalent circuit

The role of mechanical pressure difference in the generation of membrane voltage under conditions of concentration polarization

A multi-scale model for electrokinetic transport in networks of micro-scale and nano-scale pores

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