Experimental 3D concentration profiles along an electrodialysis channel reveal a strong effect of natural convection

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F23%3A43926888" target="_blank" >RIV/60461373:22340/23:43926888 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/60461373:22810/23:43926888 RIV/49777513:23640/23:43968952

Výsledek na webu

<a href="http://dx.doi.org/10.1016/j.desal.2022.116302" target="_blank" >http://dx.doi.org/10.1016/j.desal.2022.116302</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.desal.2022.116302" target="_blank" >10.1016/j.desal.2022.116302</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Experimental 3D concentration profiles along an electrodialysis channel reveal a strong effect of natural convection

Popis výsledku v původním jazyce

Electrodialysis and electrodeionization separate ionic components from processed water solutions by applying a DC electric field on a stack of ion-exchange membranes. The ion separation indicates ionic concentration changes along the channels in the membrane modules. Simultaneously, concentration polarization at the ion-exchange membranes causes ionic concentration variations across the channels. We constructed a milifluidic cell with a diluate channel to measure spatial concentration profiles under single-path electrodialysis conditions. Desalination of 0.1 M NaCl solution showed that the concentration decreases linearly along the channel when connecting relatively low average current densities (&lt; 30 A/m2), yielding &lt;70 % desalination. Higher average current densities causing desalination close to 100 % produced nonlinear concentration profiles characterized by a steep linear drop followed by an almost constant and small concentration region. We show that at a current density of 50 A/m2, only one-third of the diluate channel is employed for desalination. Interestingly, uniform concentration profiles developed across the channels even at high polarization current densities. Unlike constant concentrations across the channel, we found substantial concentration variation in the vertical direction of the channel, indicating the effect of density gradients and natural convection. This effect was confirmed by optical microscopy and particle image velocimetry of this convection in stagnant solution layers. Natural convection, thus, can represent a mechanism intensifying the mass transfer from the solution bulk to the membrane surfaces. © 2022

Název v anglickém jazyce

Experimental 3D concentration profiles along an electrodialysis channel reveal a strong effect of natural convection

Popis výsledku anglicky

Electrodialysis and electrodeionization separate ionic components from processed water solutions by applying a DC electric field on a stack of ion-exchange membranes. The ion separation indicates ionic concentration changes along the channels in the membrane modules. Simultaneously, concentration polarization at the ion-exchange membranes causes ionic concentration variations across the channels. We constructed a milifluidic cell with a diluate channel to measure spatial concentration profiles under single-path electrodialysis conditions. Desalination of 0.1 M NaCl solution showed that the concentration decreases linearly along the channel when connecting relatively low average current densities (&lt; 30 A/m2), yielding &lt;70 % desalination. Higher average current densities causing desalination close to 100 % produced nonlinear concentration profiles characterized by a steep linear drop followed by an almost constant and small concentration region. We show that at a current density of 50 A/m2, only one-third of the diluate channel is employed for desalination. Interestingly, uniform concentration profiles developed across the channels even at high polarization current densities. Unlike constant concentrations across the channel, we found substantial concentration variation in the vertical direction of the channel, indicating the effect of density gradients and natural convection. This effect was confirmed by optical microscopy and particle image velocimetry of this convection in stagnant solution layers. Natural convection, thus, can represent a mechanism intensifying the mass transfer from the solution bulk to the membrane surfaces. © 2022

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20402 - Chemical process engineering

Projekt

<a href="/cs/project/GA20-21263S" target="_blank" >GA20-21263S: Analýza elektrodialýzy v milifluidních průtočných systémech</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2023

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Desalination

ISSN

0011-9164

e-ISSN

—

Svazek periodika

548

Číslo periodika v rámci svazku

548

Stát vydavatele periodika

NL - Nizozemsko

Počet stran výsledku

10

Strana od-do

—

Kód UT WoS článku

000904568000003

EID výsledku v databázi Scopus

2-s2.0-85143793308