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

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.

2020 ◽  
Vol 175 ◽  
pp. 334-340
Author(s):  
Kyung Jin Min ◽  
Eun Joo Oh ◽  
Gabin Kim ◽  
Joo Hyeong Kim ◽  
Jun Hee Ryu ◽  
...  

2014 ◽  
Vol 68 (3) ◽  
Author(s):  
Natália Káňavová ◽  
Lubomír Machuča ◽  
David Tvrzník

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.


1977 ◽  
Vol 32 (11-12) ◽  
pp. 905-907 ◽  
Author(s):  
Hans-Joachim Breter

Abstract An improved method is described for the separation of 22 compounds normally related to purine and 6-thiopurine metabolism in biological materials using high-pressure liquid cation-exchange chromatography on strongly acidic exchange resin. The column (0.18 × 100 cm) is eluted with 0.4 ᴍ ammonium formate, pH 4.6, at a linear flow velocity of 5.2 cm · min-1 at 50 °C. The elution volumes of sulphate anions, allopurinol, 6-thioxanthine, adenine, adenosine, and guanosine are demonstrated additionally to further 16 purine and 6-thiopurine compounds.


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