Water splitting proton-barriers for mineral membrane fouling control and their optimization by accurate pulsed modes of electrodialysis

Recent electrodialysis (ED) research put forward the way a mineral fouling growth occurring on cation-exchange membrane (CEM) was reduced by a pulsed electric field (PEF) ratio of repetitive current pulsation (ton/toff=10 s/10 s). The current study applies a set of PEF on-duty ratios of even higher frequencies to further control membrane fouling, and to maximize the process performance during the ED of a solution containing a high Mg/Ca ratio (2/5). The on-duty ratios were two PEFs ratio 0.5 (ton/toff=5 s/10 s, and 10 s/20 s), two PEFs ratio 1 (ton/toff=5 s/5 s, and 10 s/10 s), and two PEFs ratio 2 (ton/toff=10 s/5 s, and 20 s/10 s). The repetitive pulsation of the ratios 10 s/5 s and 5 s/5 s enhanced the process performance (DRs of 58.48% and 59.64%), and suppressed CEM fouling on the diluate side. The ratio 10 s/5 s having a pause shorter than the pulse reduced fouling also on the concentrate side through steady water splitting proton generation that neutralized OH− leakage through CEM. No severe mineral precipitation occurred on AEM. The application of optimized water splitting proton-barriers for mineral fouling control is crucial.