High effective electrodialytic whey desalination at high temperature

Abstract

The temperature dependence of desalination and the energy efficiency of electrodialysis of evaporated sweet whey were investigated. Electrodialysis was performed in the temperature range 15–55 °C. The time required for desalination of whey to a 62% degree of desalination decreased by a factor of 2 and 2.5 when the temperature was changed from 15 to 25 °C, respectively, to 55 °C. Total mass flux increased 3 times with increased temperature from 15 to 55 °C, whereas specific energy consumption was the same for all temperatures, indicating that the energy efficiency of whey desalination increased with increasing temperature. The removal of citric acid also improved with increasing temperature. Changes in transport properties of the ion-exchange membranes after heat treatment at 15–55 °C in contact with deionised water are reported.