Membrane desalination is mature and cost-effective. However, its water recovery is limited due to the oversaturation of 2:2 salts (e.g., CaSO4, CaCO3) in the concentrate, eventually leading to scaling. Antiscalant dosing or ion-exchange processes mitigate this limitation, but these measures have negative operational and environmental impacts. Alternatively, studies have proposed Electrodialysis Metathesis. The EDM process avoids the oversaturation of 2:2 salts; instead, it concentrates highly soluble 1:2 (e.g., NaSO4) and 2:1 salts (e.g., CaCl2) separately. However, the process requires the addition of NaCl. We aim to develop a high-recovery desalination scheme, including EDM, but with electricity and source water as sole inputs. NaCl will be first recycled from the feed streams and then refed for the EDM process. The main development and application challenges are the complex interaction between the source water’s ionic composition, the four types of ion-selective membranes, the process conditions, and the resulting multiple streams. The goal is to give an experimental proof of concept and validate the technology in the lab with real water, and for practical use cases provided by our industrial partners.
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