Mitigation of mineral scaling in membrane capacitive deionization – Understanding the role of pH changes and carbonates

Mineral scaling in water desalination is caused by the precipitation of salts, which is affected by various factors such as the presence of specific ions, solution pH, and temperature. While extensively researched in technologies like reverse osmosis (RO), understanding mineral scaling in membrane capacitive deionization (MCDI) remains limited. During MCDI operation, the pH of the effluent fluctuates, potentially triggering mineral scaling. The present study investigates how the adsorption and desorption of HCO3− ions and the distribution of dissolved inorganic carbon (DIC) species (H2CO3, HCO3−, and CO32−) drive pH changes. We examine mineral scaling formation at various water recoveries during MCDI operation using different thicknesses of the anion exchange membrane (AEM). Our findings indicate that pH changes increase with higher water recoveries and that increasing the AEM thickness provides a pathway to enhance MCDI stability, consequently lowering the need for anti-scaling agents.

Bibliographic Details

Main Authors:	Arulrajan, Antony Cyril, Wu, Min Chen, Porada, Slawomir, Dykstra, Jouke E., Hou, Chia Hung, van der Wal, Albert
Format:	Article/Letter to editor biblioteca
Language:	English
Subjects:	Dissolved inorganic carbon, Ion-exchange membrane, Membrane capacitive deionization, Mineral scaling, pH changes,
Online Access:	https://research.wur.nl/en/publications/mitigation-of-mineral-scaling-in-membrane-capacitive-deionization
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