scholarly journals A Tool for a Spacer Material and Ion-exchange Membrane Compatibility Evaluation for Electrodialysis Module Design

2017 ◽  
Vol 62 (2) ◽  
pp. 144
Author(s):  
Jakub Fehér ◽  
Kateřina Keslerová ◽  
Michal Amrich

Electrodialysis is a widely used separation process for wastewater treatment, concentration of valuable products or production of organic acids. However, unwanted phenomena can occur during the operation of electrodialysis stacks such as internal leakage and/or external leak. In this study, a new simple tool is presented for testing materials suitable for use as spacers used in ED. This cell for testing leaks simulates ED stack and therefore allowing external leaks to be tested. Regarding tests results suitable materials for an ED scale-up can be chosen. Tests were done for three different pressures (1.5, 2 and 2.5 bar) and three different temperatures (25, 40 and 60 °C). To maintain the same conditions, the test cell was tightened by defined force in the range of 850 to 870 N. In the testing stack different combinations of membrane, and spacers were tested. It was found that with increasing temperature leaks decrease. Parameters that influence external leaks most are surface roughness, texture a hardness of ion-exchange membrane and spacer material.

2021 ◽  
Vol 629 ◽  
pp. 119271
Author(s):  
Jiří Charvát ◽  
Petr Mazúr ◽  
Martin Paidar ◽  
Jaromír Pocedič ◽  
Jiří Vrána ◽  
...  

Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 400
Author(s):  
Hajime Kamebuchi ◽  
Satoshi Tamaki ◽  
Atsushi Okazawa ◽  
Norimichi Kojima

The development and the photophysical behavior of a transparent ion-exchange membrane based on a pH-sensitive polypyridyl ruthenium(II) complex, [(bpy)2RuII(H2bpib)RuII(bpy)2](ClO4)4 (bpy = 2,2′-bipyridine, H2bpib = 1,4-bis([1,10]phenanthroline[5,6-d]-imidazol-2-yl)benzene), are experimentally and theoretically reported. The emission spectra of [(bpy)2RuII(H2bpib)RuII(bpy)2]@Nafion film were observed between pH 2 and pH 11 and showed the highest relative emission intensity at pH 5 (λmaxem = 594.4 nm). The relative emission intensity of the film significantly decreased down to 75% at pH 2 and 11 compared to that of pH 5. The quantum yields (Φ) and lifetimes (τ) showed similar correlations with respect to pH, Φ = 0.13 and τ = 1237 ns at pH 5, and Φ = 0.087 and τ = 1014 ns and Φ = 0.069 and τ = 954 ns at pH 2 and pH 11, respectively. These photophysical data are overall considerably superior to those of the solution, with the radiative- (kr) and non-radiative rate constants (knr) at pH 5 estimated to be kr = 1.06 × 105 s−1 and knr = 7.03 × 105 s−1. Density functional theory calculations suggested the contribution of ligand-to-ligand- and intraligand charge transfer to the imidazolium moiety in Ru-H3bpib species, implying that the positive charge on the H3bpib ligand works as a quencher. The Ru-Hbpib species seems to enhance non-radiative deactivation by reducing the energy of the upper-lying metal-centered excited state. These would be responsible for the pH-dependent “off-on-off” emission behavior.


RSC Advances ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 4210-4220
Author(s):  
Mohd. Zeeshan ◽  
Rais Ahmad ◽  
Asif Ali Khan ◽  
Aftab Aslam Parwaz Khan ◽  
Guillermo C. Bazan ◽  
...  

A polycarbazole-Sn(iv) arsenotungstate (Pcz-SnAT) nanocomposite cation exchanger membrane (CEM) was prepared via the casting solution technique utilizing polycarbazole-Sn(iv) arsenotungstate and PVC (polyvinyl chloride) as a binder.


1981 ◽  
Vol 18 (5-6) ◽  
pp. 899-905 ◽  
Author(s):  
I. Ishigaki ◽  
T. Sugo ◽  
K. Senoo ◽  
T. Takayama ◽  
S. Machi ◽  
...  

1987 ◽  
Vol 60 (6) ◽  
pp. 2215-2219 ◽  
Author(s):  
Yutaka Hirata ◽  
Masashi Date ◽  
Yukiko Yamamoto ◽  
Akira Yamauchi ◽  
Hideo Kimizuka

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