Ion-Exchange Membranes

Yoshinobu Tanaka, Seung-Hyeon Moon, Victor V. Nikonenko, Tongwen Xu
2012 International Journal of Chemical Engineering  
Principles of ion transport across ion-exchange membranes had been investigated using biological membranes in old time. Industrial application of the membranes started after the invention of artificial membranes in 1950. Ion-exchange membrane electrodialysis is now one of the basic technology in saline water desalination industry. It is also applied to many fields such as demineralization and reuse of sewage or industrial waste, refining of amino acid solutions, production of organic and
more » ... organic and inorganic chemicals, membrane reactors, among others. Further, the membranes are applied to the succeeding technology such as electrodialysis reversal, bipolar membrane electrodialysis, electrodeionization, electrolysis, diffusion dialysis, fuel cell, reverse electrodialysis, among others. This special issue presents the newest investigation on ion-exchange membranes submitted from each field. It includes topics in the fundamental studies and application studies such as membrane preparation, membrane characterization, membrane application, environmental problem; process design and operation, among others. Fundamental studies are the basis of the application studies. At the same time, the application studies induce the development of the fundamental studies. Both studies influence each other and consequently contribute to the technology development. Based on the history of ion-exchange membranes, the following ten articles published in this special issue must induce the development of succeeding technology. In the first article "Reactivity of phenol allylation using phase-transfer catalysis in ion-exchange membrane reactor," Wu and Fu have reported the reactivity of phenol allylation using quaternary ammonium salt phase-transfer catalysts in ion-exchange membrane reactors incorporated with the laboratory-produced membrane. They have immobilized the catalyst in the pore of an ion-exchange membrane. That allowed them to benefit the permselective as well as the catalytic functions of the new membrane. The study investigates the reactivity of phenol allylation using quaternary ammonium salt as a phase-transfer catalyst in several types of membrane reactors. Optimum reactivity and turnover of phenol allylation were obtained using a respond surface methodology. The contact angle, water content, and crosslinkage degree were measured to understand the microenvironment in the ion-exchange membrane. The second article is "Performance of a 1 kW class nafion-PTFE composite membrane fuel cell stack" addressed by Kirshnamurthy et al. The membranes have been prepared by impregnation of Nafion into the expanded polytetrafluoroethylene (EPTFE) matrix. Nafion loading in the membranes was kept at lower amount of 2 mg/cm 2 . The lower amount of electrolyte per unit area in the composite membranes offers cost advantageous compared to conventional membranes. The composite membranes (30 μm thickness) had higher thermal stability and mechanical strength compared to the conventional membranes (50 μm thickness). The durability of single pass cells was tested. The performance of the membrane electrode assembly (20-cell stack, 330 cm 2 active area) have been reported and it was comparable to that of the conventional membrane. In the third article, "Study of chromium removal by electrodialysis of tannery and metal-finishing effluents" by Moura
doi:10.1155/2012/906952 fatcat:uughezjp4bdmjnz7i5hhqopl3a