Limiting Current Studies in an Electrodialysis Cell: Influence of Mean Linear Velocity and KCl Concentration in the Diluate Channel

2019 ◽  
Vol 20 (1) ◽  
pp. 83-90
Author(s):  
Lucia G. Alvarado Montalvo ◽  
Carmen Ojeda Escamilla ◽  
Jose A. Delgadillo Gómez ◽  
Israel Rodríguez- Torres
Keyword(s):  
Linear Velocity ◽  
Limiting Current ◽  
Electrodialysis Cell

Velocity profiles and limiting current in an annular electrodialysis cell in pulsed flow

1997 ◽  
Vol 52 (5) ◽  
pp. 843-851 ◽  
Author(s):  
V. Pérez-Herranz ◽  
J. García-Antón ◽  
J.L. Guiñón
Keyword(s):  
Velocity Profiles ◽  
Limiting Current ◽  
Pulsed Flow ◽  
Electrodialysis Cell

scholarly journals Electrodialytic whey demineralization involving polymer-inorganic membranes, anion exchange resin and graphene-containing composite

2019 ◽  
pp. 163-171 ◽  
Author(s):  
Valerii Myronchuk ◽  
Yurii Zmievskii ◽  
Yuliya Dzyazko ◽  
Ludmila Rozhdestveska ◽  
Vladimir Zakharov ◽  
...  
Keyword(s):  
Anion Exchange ◽  
Zirconium Dioxide ◽  
Exchange Resin ◽  
Anion Exchange Resin ◽  
Limiting Current ◽  
Inorganic Membranes ◽  
Hydrated Zirconium Dioxide ◽  
Electrodialysis Cell ◽  
Mineral Components ◽  
Exchange Resins

Electrodialysis of cheese whey was performed using polymer membranes modified with zirconium hydrophosphate (cation exchange separator) and hydrated zirconium dioxide (anion exchange material). Both neutral and acidic solutions were used as a concentrate. As found, a 0.1 M HCl solution is preferable: the current efficiency towards mineral components and desalination degree reach 75-81 % and 90 % respectively, when the current does not exceed limiting current for cations. Anion exchange resin, as well as the composite containing zirconium dioxide and oxidized graphene, were involved in desalination. The composite adsorbs preferably cations, adsorption of anions is depressed. Its adsorption capacity is 1.2 (K+) and 0.25 (CL-) mmol g-1. Whey passed subsequently through the electrodialysis cell and beds of these materials. This approach allowed us to achieve the demineralization degree of 99%, and minimize losses of organic substances. Adsorption materials can be used repeatedly. The advantage of the composite over ion exchange resins is facile regeneration.

Compact and efficient gas diffusion electrodes based on nanoporous alumina membranes for microfuel cells and gas sensors

The Analyst ◽  
2020 ◽  
Vol 145 (1) ◽  
pp. 122-131 ◽  
Author(s):  
Wanda V. Fernandez ◽  
Rocío T. Tosello ◽  
José L. Fernández
Keyword(s):  
Response Times ◽  
Hydrogen Oxidation ◽  
Fast Response ◽  
Gas Diffusion ◽  
Limiting Current ◽  
Gas Diffusion Electrodes ◽  
Nanoporous Alumina ◽  
Alumina Membranes ◽  
Current Densities ◽  
Microfuel Cells

Gas diffusion electrodes based on nanoporous alumina membranes electrocatalyze hydrogen oxidation at high diffusion-limiting current densities with fast response times.

3D Scan Matching using Linear Velocity Estimation for Forest Road Localization

2020 ◽  
Vol 140 (9) ◽  
pp. 1082-1090
Author(s):  
Hiroyuki Nakagomi ◽  
Yoshihiro Fuse ◽  
Yasuki Nagata ◽  
Hironaga Miyamoto ◽  
Masashi Yokotsuka ◽  
...  
Keyword(s):  
Linear Velocity ◽  
Velocity Estimation ◽  
Scan Matching ◽  
Forest Road ◽  
3D Scan

Marcus-Hush Theory Revealed by Electron Tunneling Through Hexagonal Boron Nitride

2019 ◽  
Author(s):  
Matěj Velický ◽  
Sheng Hu ◽  
Colin R. Woods ◽  
Peter S. Toth ◽  
Viktor Zólyomi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Boron Nitride ◽  
Electron Tunneling ◽  
Hexagonal Boron Nitride ◽  
Large Body ◽  
Liquid Solution ◽  
Limiting Current ◽  
Electron Transfer Rate Constant ◽  
Electrochemical Parameters ◽  
Voltammetric Measurements

Marcus-Hush theory of electron transfer is one of the pillars of modern electrochemistry with a large body of supporting experimental evidence presented to date. However, some predictions, such as the electrochemical behavior at microdisk electrodes, remain unverified. Herein, we present a study of electron tunneling across a hexagonal boron nitride barrier between a graphite electrode and redox levels in a liquid solution. This was achieved by the fabrication of microdisk electrodes with a typical diameter of 5 µm. Analysis of voltammetric measurements, using two common redox mediators, yielded several electrochemical parameters, including the electron transfer rate constant, limiting current, and transfer coefficient. They show a significant departure from the Butler-Volmer behavior in a clear manifestation of the Marcus-Hush theory of electron transfer. In addition, our system provides a novel experimental platform, which could be applied to address a number of scientific problems such as identification of reaction mechanisms, surface modification, or long-range electron transfer.

Electroreduction of Cr(VI) from solutions of bifunctional alcohols

1989 ◽  
Vol 54 (10) ◽  
pp. 2638-2643
Author(s):  
David I. Balanchivadze ◽  
Tamara R. Chelidze ◽  
Jondo J. Japaridze
Keyword(s):  
Activation Energy ◽  
Ethylene Glycol ◽  
Electrode Surface ◽  
Frequency Factor ◽  
Limiting Current ◽  
Factor Log ◽  
Standard Rate ◽  
Standard Rate Constant ◽  
Chromate Ion ◽  
Activation Energy Of Diffusion

The effect of bifunctional alcohols ethylene glycol (EG) and 1,2-propylene glycol (1,2 PG) on the kinetic parameters for the irreversible chromate ion reduction were investigated by polarographic and coulometric methods of analysis. The electroreduction of chromate ion in neutral bifunctional alcohol solutions proceeds according to the scheme: Cr(VI)–Cr(III)–Cr(II) and the values of the standard rate constant k*0 decrease in the order H2O > EG > 1,2 PG. The values of real activation energy, Q, activation energy of diffusion, QD, and frequency factor log A° have been calculated. The obtained values of QD as well as Q proved the diffusion nature of limiting current. The values of the frequency factor log A° decrease in the order H2O > EG > 1,2 PG, which points to a less favourable orientation of the electroactive ions at the electrode surface in glycols.

On the convective diffusion under partial slip at wall

1989 ◽  
Vol 54 (4) ◽  
pp. 967-980 ◽  
Author(s):  
Ondřej Wein ◽  
Petr Kučera
Keyword(s):  
Mass Transfer ◽  
Numerical Solution ◽  
Analytic Solution ◽  
Convective Diffusion ◽  
Linear Velocity ◽  
Partial Slip ◽  
Accurate Calculation ◽  
Transfer Coefficients ◽  
Empirical Formulas ◽  
Mass Transfer Coefficients

Extended Leveque problem is studied for linear velocity profiles, vx(z) = u + qz. The existing analytic solution is reconsidered and shown to be inapplicable for the accurate calculation of mean mass-transfer coefficients. A numerical solution is reported and its accuracy is checked in detail. Simple but fairly accurate empirical formulas are suggested for the calculating of local and mean mass-transfer coefficients.

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