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. (c) 2013 Elsevier B.V. All rights reserved