Electrolysis study on water transfer number of Na~+ through DF988 ion-exchange membrane

In the process of ion-exchange membrane electrolysis,ions passing through an ion exchange membrane are accompanied by a solvation shell of water molecules,which is known as the electro-osmotic water flux or water transfer phenomenon.The structure of domestic DF988 ion-exchange membrane was introduced briefly.The attenuated total reflectance Fourier transform infrared(ATR-FTIR) spectra revealed that DF988 membrane do contain a sulfonic polymer layer and a carboxylic layer,the barrier layer.Research on water transfer phenomenon is conducive to understand the transference performance of DF988 membrane.The water transfer was investigated systematically using self-made electrolysis equipment.The water transfer number(tw) and the sodium chloride content in NaOH were determined under different conditions,including anolyte concentration,catholyte concentration,current density and temperature.The results show that water transfer number was remarkably affected by the concentration of the electrolytes.The decreasing of anolyte concentration can increase the water transfer number.While the current density and temperature have an obvious influence on the sodium chloride content in NaOH.