Overlimiting convection at a heterogeneous cation-exchange membrane studied by particle image velocimetry

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22340%2F22%3A43925229" target="_blank" >RIV/60461373:22340/22:43925229 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/49777513:23640/22:43965954

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0376738821009881?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0376738821009881?via%3Dihub</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.memsci.2021.120048" target="_blank" >10.1016/j.memsci.2021.120048</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Overlimiting convection at a heterogeneous cation-exchange membrane studied by particle image velocimetry

Popis výsledku v původním jazyce

Electroconvection and gravitational convection are recognized as the primary mechanisms driving overlimiting currents in ion-exchange systems. Here, we use particle image velocimetry (PIV) to characterize the convection on a small piece of a commercially available heterogeneous cation-exchange membrane. We perform chronoamperometric measurements under various experimental conditions and simultaneously record the developed convection at the membrane-electrolyte solution interface using tracking particles. The convection is observed independently in horizontal and vertical planes, capturing flow fields pertinent to electroconvection and gravitational convection. PIV analysis computes velocity vector fields we employ to calculate the volumetric flow rate through a virtual semi-cylindrical wall around the membrane. The volumetric flow rate represents a way how to quantify the intensity of electroconvection. The electroconvection recorded on the horizontal plane manifests itself as a local short-range chaotic whirring localized at the membrane surface superimposed by two long-range counter-current vortices. The volumetric flow rate associated with the two counter-current vortices almost linearly increases with voltage and decreases with increasing concentration. The stagnant points of the vortices localize from 100 to 450 μm away from the membrane. The convection observed on the vertical plane occurs as a result of electroconvection and gravitational convection. We show that gravitational convection eventually dominates and produces an upward-directed intensive flow with similar values of characteristic velocities as the electroconvection. The development of the gravitational convections is approximately one order of magnitude slower (on the order of seconds) than that of electroconvection (on the order of hundreds of milliseconds).

Název v anglickém jazyce

Overlimiting convection at a heterogeneous cation-exchange membrane studied by particle image velocimetry

Popis výsledku anglicky

Electroconvection and gravitational convection are recognized as the primary mechanisms driving overlimiting currents in ion-exchange systems. Here, we use particle image velocimetry (PIV) to characterize the convection on a small piece of a commercially available heterogeneous cation-exchange membrane. We perform chronoamperometric measurements under various experimental conditions and simultaneously record the developed convection at the membrane-electrolyte solution interface using tracking particles. The convection is observed independently in horizontal and vertical planes, capturing flow fields pertinent to electroconvection and gravitational convection. PIV analysis computes velocity vector fields we employ to calculate the volumetric flow rate through a virtual semi-cylindrical wall around the membrane. The volumetric flow rate represents a way how to quantify the intensity of electroconvection. The electroconvection recorded on the horizontal plane manifests itself as a local short-range chaotic whirring localized at the membrane surface superimposed by two long-range counter-current vortices. The volumetric flow rate associated with the two counter-current vortices almost linearly increases with voltage and decreases with increasing concentration. The stagnant points of the vortices localize from 100 to 450 μm away from the membrane. The convection observed on the vertical plane occurs as a result of electroconvection and gravitational convection. We show that gravitational convection eventually dominates and produces an upward-directed intensive flow with similar values of characteristic velocities as the electroconvection. The development of the gravitational convections is approximately one order of magnitude slower (on the order of seconds) than that of electroconvection (on the order of hundreds of milliseconds).

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

20401 - Chemical engineering (plants, products)

Projekt

<a href="/cs/project/GA18-13491S" target="_blank" >GA18-13491S: Interakce nabitých polymerů s heterogenními iontově-výměnnými membránami</a><br>

Návaznosti

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

Rok uplatnění

2022

Kód důvěrnosti údajů

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

Název periodika

Journal of Membrane Science

ISSN

0376-7388

e-ISSN

1873-3123

Svazek periodika

643

Číslo periodika v rámci svazku

MAR 1 2022

Stát vydavatele periodika

BE - Belgické království

Počet stran výsledku

8

Strana od-do

120048

Kód UT WoS článku

000744265900001

EID výsledku v databázi Scopus

2-s2.0-85118877099