Influence of linear flow velocity and ion concentration on limiting current density during electrodialysis

2020 ◽  
Vol 175 ◽  
pp. 334-340
Author(s):  
Kyung Jin Min ◽  
Eun Joo Oh ◽  
Gabin Kim ◽  
Joo Hyeong Kim ◽  
Jun Hee Ryu ◽  
...  
Keyword(s):  
Flow Velocity ◽  
Current Density ◽  
Ion Concentration ◽  
Limiting Current ◽  
Linear Flow ◽  
Limiting Current Density ◽  
Linear Flow Velocity

Determination of limiting current density for different electrodialysis modules

2014 ◽  
Vol 68 (3) ◽  
Author(s):  
Natália Káňavová ◽  
Lubomír Machuča ◽  
David Tvrzník
Keyword(s):  
Ammonium Nitrate ◽  
Flow Velocity ◽  
Current Density ◽  
Nitrate Concentration ◽  
Nitrate Solution ◽  
Limiting Current ◽  
Linear Flow ◽  
Limiting Current Density ◽  
Ammonium Nitrate Solution ◽  
Linear Flow Velocity

AbstractLimiting current density of ammonium nitrate solution in laboratory-, pilot-, and industrial-scale electrodialysis modules were determined to provide a method for the prediction of the limiting current density of ammonium nitrate solutions at any conditions. The current-voltage curve was measured in each case and the limiting current density was evaluated using the dependence of the derivative, dI/dU, on the electric current, I. The limiting current was determined as a current at which the derivative dI/dU equals zero. The developed method enables not only the prediction of the limiting current density but the limiting cut and limiting flux can be determined concurrently at any linear flow velocity of the diluate and inlet ammonium nitrate concentration. It could help to prevent working in the overlimiting region and to avoid undesirable decrease of current efficiency and pH changes. The limiting cut is the maximal cut that can be obtained at certain linear flow velocity and module geometry irrespective of the inlet ammonium nitrate concentration and it is very useful information when designing a new electrodialysis unit for specific application.

scholarly journals Numerical Investigation of the Effect of Two-Dimensional Surface Waviness on the Current Density of Ion-Selective Membranes for Electrodialysis

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1397
Author(s):  
Andreas Gross ◽  
Arthur Morvezen ◽  
Pedro Castillo Gomez ◽  
Xuesong Xu ◽  
Pei Xu
Keyword(s):  
Surface Roughness ◽  
Current Density ◽  
Stokes Equations ◽  
Membrane Surface ◽  
Ion Concentration ◽  
Limiting Current ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Limiting Current Density ◽  
Selective Membranes

Ion-selective membranes are an important component of electrodialysis stacks for desalination. Manufacturing imperfections or slight inhomogeneity of the material can lead to minute membrane surface imperfections. Two-dimensional solutions of the coupled Poisson–Nernst–Planck and Navier–Stokes equations were sought for a perfectly smooth membrane and for membranes with well-defined small-amplitude harmonic surface roughness. The simulations were carried out with the validated rheoEFoam solver by Pimenta and Alves. In the overlimiting regime, the electric field is strong enough for an electrokinetic instability to occur. The instability leads to disturbance growth and the formation of electro-convection cells, which strongly increase the current density. The present simulations show that with an increasing ion concentration and applied voltage, the instability becomes stronger and the overlimiting regime is reached earlier. The limiting current density shows a noticeable dependence on the wavelength of the surface roughness. When the wavelength of the surface roughness is incommensurate with the wavelength of the naturally occurring instability, the limiting current density is increased. Since production membranes will always have some degree of surface roughness, this suggests that membrane surface treatments which favor certain wavelengths may have an effect on the overall membrane performance.

scholarly journals Flow velocity and cell pair number effect on current efficiency in plating wastewater treatment through electrodialysis

2020 ◽  
Vol 26 (2) ◽  
pp. 190502-0
Author(s):  
Kyung Jin Min ◽  
Joo Hyeong Kim ◽  
Eun Joo Oh ◽  
Jun Hee Ryu ◽  
Ki Young Park
Keyword(s):  
Heavy Metals ◽  
Current Efficiency ◽  
Flow Velocity ◽  
Removal Efficiency ◽  
Limiting Current ◽  
Toxic Substances ◽  
Linear Flow ◽  
Design Elements ◽  
Cell Pair ◽  
Linear Flow Velocity

Electrodialysis has been used for treating toxic substances such as heavy metals and minimizing secondary environmental pollution problems effectively. However, electrodialysis depends on the operating parameters as well as fluid dynamics and electrical properties. This study provides design elements for the treatment of heavy metal-containing wastewater by electrodialysis. We found that the limiting current density (LCD) is proportional but not completely linear to the diluate concentration over a threshold value. In contrast, it is linear to the linear flow velocity for the whole range. As the number of cell pairs increases, because linear flow velocity and LCD increase, the removal efficiency of heavy metals also increases. Therefore, for highly concentrated wastewater, increasing the linear flow velocity, the applied voltage, and the number of cell pairs can effectively improve removal efficiency. It was found that the current efficiency is as low as 17% when the removal efficiency of heavy metals exceeds 95%. Thus, it is necessary to select an operating range that optimizes the operating and initial investment costs for the effective removal of heavy metals using electrodialysis.

scholarly journals Limiting Current Density of Oxygen Reduction under Ultrathin Electrolyte Layers: From the Micrometer Range to Monolayers

2021 ◽  
Vol 8 (4) ◽  
pp. 712-718
Author(s):  
Xiankang Zhong ◽  
Matthias Schulz (née Uebel) ◽  
Chun‐Hung Wu ◽  
Martin Rabe ◽  
Andreas Erbe ◽  
...  
Keyword(s):  
Oxygen Reduction ◽  
Current Density ◽  
Limiting Current ◽  
Limiting Current Density

scholarly journals Demineralization of Rehydrated Cheese Whey by Electrodialysis. Effects of deashing rates and solid concentration on limiting current density.

1991 ◽  
Vol 17 (5) ◽  
pp. 1006-1011 ◽  
Author(s):  
Yasunobu Hiraoka ◽  
Akira Tomizawa ◽  
Tatsuki Oguchi ◽  
Etsuko Suzuki ◽  
Masanobu Koutake
Keyword(s):  
Current Density ◽  
Cheese Whey ◽  
Limiting Current ◽  
Solid Concentration ◽  
Limiting Current Density

Polarization Characteristics to Wear Ratio of Anti-Fouling Paint

2015 ◽  
Vol 1110 ◽  
pp. 179-184
Author(s):  
Kyung Man Moon ◽  
Dong Hyun Park ◽  
Yun Hae Kim ◽  
Tae Sil Baek
Keyword(s):  
Current Density ◽  
Corrosion Potential ◽  
Wear Test ◽  
Life Time ◽  
Point Of View ◽  
Limiting Current ◽  
Limiting Current Density ◽  
Wear Ratio ◽  
Polarization Characteristics ◽  
Lower Variation

Recently, anti-fouling paints which does not include the poison components such as tin (Sn) free, copper (Cu) free have been increasingly developed in order to decrease the contamination of marine environment. Moreover, the wear ratios of these anti-fouling paints are very important problem to prolong their life time in economical and environmental point of view. In this study, four types of anti-fouling paints as self-polishing type were investigated on the relationship between their polarization characteristics and wear ratios. Relationship between wear ratio and variation ratio of polarization resistance measured in corrosion potential was not well matched with each other. However, there was a good agreement between the wear ratio and variation ratio of diffusion limiting current density, for example, the higher or the lower variation ratio of diffusion limiting current density, wear ratio also increased or decreased respectively. Consequently, it is suggested that we can qualitatively expect the life time and wear degree of anti-fouling paint by only measuring the polarization characteristics before the wear test is practically performed in the field.Keywords: Anti-fouling paint, Self-polishing type, Polarization characteristics, Wear ratio, Diffusion limiting current density, Corrosion Potential

Limiting current density in a crossed-field nanogap

2001 ◽  
Vol 64 (1) ◽  
Author(s):  
L. K. Ang ◽  
T. J. T. Kwan ◽  
Y. Y. Lau
Keyword(s):  
Current Density ◽  
Limiting Current ◽  
Limiting Current Density
Sign in / Sign up

Export Citation Format

Share Document