Improving electrodialysis separation efficiency of minerals from acid whey by nano-filtration pre-processing

Acid whey (AW) contains valuable minerals, such as calcium and magnesium. Electrodialysis (ED) is an efficient technology to recover these minerals; however, the less nutritional sodium will also be recovered during ED. AW was processed by nanofiltration prior to ED in order to change the ratio between the monovalent and divalent ions. The nano-filtration increased the efficiency of the ED process regarding recovery of Ca2+ and Mg2+ ions by 70% and 67%, respectively, while it did not affect the K+, Na+, phosphates and lactate. The spent energy was more effectively used to recover Ca2+ in the nano-filtrated AW.