How does a transition zone affect the electric field enhanced water dissociation in bipolar membranes?

1994 ◽  
Vol 98 (2) ◽  
pp. 202-205 ◽  
Author(s):  
Salvador Mafé ◽  
Patricio Ramirez ◽  
José A. Manzanares
Keyword(s):  
Electric Field ◽  
Transition Zone ◽  
Water Dissociation ◽  
Bipolar Membranes

Bipolar membrane polarization behavior with systematically varied interfacial areas in the junction region

2021 ◽  
Author(s):  
Subarna Kole ◽  
Gokul Venugopalan ◽  
Deepra Bhattacharya ◽  
Le Zhang ◽  
John Cheng ◽  
...  
Keyword(s):  
Electric Field ◽  
Water Dissociation ◽  
Bipolar Membrane ◽  
Junction Region ◽  
Bipolar Membranes ◽  
Membrane Polarization ◽  
Interfacial Areas ◽  
Left Image ◽  
The Right ◽  
The Relationship

Left image is the relationship for the overpotential for water dissociation as a function of bipolar junction electric field whereas the right image presents micrographs and the procedure to make bipolar membranes with micropatterned interfaces.

The balance of electric field and interfacial catalysis in promoting water dissociation in bipolar membranes

2018 ◽  
Vol 11 (8) ◽  
pp. 2235-2245 ◽  
Author(s):  
Zhifei Yan ◽  
Liang Zhu ◽  
Yuguang C. Li ◽  
Ryszard J. Wycisk ◽  
Peter N. Pintauro ◽  
...  
Keyword(s):  
Electric Field ◽  
Anion Exchange ◽  
Water Dissociation ◽  
Bipolar Membranes ◽  
Electrolytic Cells ◽  
Interfacial Catalysis

Bipolar membranes maintain a steady pH in electrolytic cells through water autodissociation at the interface between their cation- and anion-exchange layers. We analyze the balance of electric field and catalysis in accelerating this reaction.

scholarly journals Mass Transfer Phenomena during Electrodialysis of Multivalent Ions: Chemical Equilibria and Overlimiting Currents

2018 ◽  
Vol 8 (9) ◽  
pp. 1566 ◽  
Author(s):  
Manuel Martí-Calatayud ◽  
Montserrat García-Gabaldón ◽  
Valentín Pérez-Herranz
Keyword(s):  
Mass Transfer ◽  
Electric Field ◽  
Membrane Surface ◽  
Industrial Effluents ◽  
Water Dissociation ◽  
Chemical Equilibria ◽  
Multivalent Ions ◽  
Current Voltage ◽  
Weak Electrolytes ◽  
New Applications

Electrodialysis is utilized for the deionization of saline streams, usually formed by strong electrolytes. Recently, interest in new applications involving the transport of weak electrolytes through ion-exchange membranes has increased. Clear examples of such applications are the recovery of valuable metal ions from industrial effluents, such as electronic wastes or mining industries. Weak electrolytes give rise to a variety of ions with different valence, charge sign and transport properties. Moreover, development of concentration polarization under the application of an electric field promotes changes in the chemical equilibrium, thus making more complex understanding of mass transfer phenomena in such systems. This investigation presents a set of experiments conducted with salts of multivalent metals with the aim to provide better understanding on the involved mass transfer phenomena. Chronopotentiometric experiments and current-voltage characteristics confirm that shifts in chemical equilibria can take place simultaneous to the activation of overlimiting mass transfer mechanisms, that is, electroconvection and water dissociation. Electroconvection has been proven to affect the type of precipitates formed at the membrane surface thus suppressing the simultaneous dissociation of water. For some electrolytes, shifts in the chemical equilibria forced by an imposed electric field generate new charge carriers at specific current regimes, thus reducing the system resistance.

Electrochemical Impedance Spectroscopy as a Performance Indicator of Water Dissociation in Bipolar Membranes

2019 ◽  
Author(s):  
marijn blommaert ◽  
david vermaas ◽  
boaz izelaar ◽  
ben in't veen ◽  
wilson smith
Keyword(s):  
Electrochemical Impedance Spectroscopy ◽  
Impedance Spectroscopy ◽  
Performance Indicator ◽  
Electrochemical Impedance ◽  
In Situ Monitoring ◽  
Water Dissociation ◽  
Bipolar Membranes ◽  
Salt Ions ◽  
And Migration

Using electrochemical impedance spectroscopy (EIS), we observed the rate of water dissociation decrease in the presence of salt ions while also observing the diffusion and migration of these salt ions, showing a clear link between the peaks observed in EIS and ion crossover. In addition, we show how EIS can be used to in-situ monitor the stability and ageing of a BPM, revealing that degradation of the BPM is more prominent in extreme pH electrolyte pairs compared to non-extreme electrolyte pairs. The in-situ monitoring of the WDR and stability of a BPM are vital methods for adequate and consistent comparison of novel designs of BPM-based systems, where EIS allows for discriminating BPM characteristics from other components even during operation. <br>

In-situ grown polyaniline catalytic interfacial layer improves water dissociation in bipolar membranes

2021 ◽  
pp. 119167
Author(s):  
Geng Li ◽  
Muhammad A. Shehzad ◽  
Zijuan Ge ◽  
Huijuan Wang ◽  
Aqsa Yasmin ◽  
...  
Keyword(s):  
Interfacial Layer ◽  
Water Dissociation ◽  
Bipolar Membranes

Effect of added salt and increase in ionic strength on skim milk electroacidification performances

2001 ◽  
Vol 68 (2) ◽  
pp. 237-250 ◽  
Author(s):  
LAURENT BAZINET ◽  
DENIS IPPERSIEL ◽  
CHRISTINE GENDRON ◽  
BEHZAD MAHDAVI ◽  
JEAN AMIOT ◽  
...  
Keyword(s):  
Ionic Strength ◽  
Protein Profile ◽  
Skim Milk ◽  
Operation Time ◽  
Water Dissociation ◽  
Bipolar Membrane ◽  
Cathode Voltage ◽  
Experimental Conditions ◽  
Bipolar Membranes ◽  
Added Salt

Bipolar-membrane electroacidification (BMEA) technology, which uses the property of bipolar membranes to split water and the demineralization action of cation-exchange membranes (CEM), was tested for the production of acid casein. BMEA has numerous advantages in comparison with conventional isoelectric precipitation processes of proteins used in the dairy industry. BMEA uses electricity to generate the desired ionic species to acidify the treated solutions. The process can be precisely controlled, as electro-acidification rate is regulated by the effective current density in the cell. Water dissociation at the bipolar membrane interface is continuous and avoids local excess of acid. In-situ generation of dangerous chemicals (acids and bases) reduces the risks associated with the handling, transportation, use and elimination of these products. The aim of this study was to evaluate the performance of BMEA in different conditions of added ionic strength (μadded = 0, 0·25, 0·5 and 1·0 M) and added salt (CaCl2, NaCl and KCl).The combination of KCl and μadded = 0·5 M gave the best results with a 45% decrease in energy consumption. The increased energy efficiency was the result of a decrease in the anode/cathode voltage difference. This was due to an increase of conductivity, produced by addition of salt, necessary to compensate for the lack of sufficiently mobile ions in the skim milk. However, the addition of salts, irrespective of type or ionic strength, increased the required operation time. The protein profile of isolates were similar under all experimental conditions, except at 1·0 M-CaCl2.

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