Carbon Dioxide-Mediated Desalination
Anand Sharadha‐Ravi Ayyar, Desta Tesfay Aregawi, Allan R. Petersen, Jonas Merlin Ibsgaard Pedersen, Rasmus Refsgaard Kragh, Mohamed M. H. Desoky, Jonas Sundberg, Lars Vinum, Jiwoong Lee
Abstract
Conventional desalination membrane technologies, although offer portable drinking water, are still energy-intensive processes. This paper proposes a potentially new approach for performing water desalination and purification by utilizing the reversible interaction of carbon dioxide (CO 2 ) with nucleophilic amines─reminiscent of the Solvay process. Based on our model studies with small molecules, CO 2 -responsive amphiphilic insoluble diamines were prepared, characterized, and applied in the formation of soda and ammonium chloride upon exposure to ambient CO 2 (1 atm), thus removing chloride ions from model and real seawater. This ion-exchange process and separation of chloride from the aqueous phase are spontaneous in the presence of CO 2 without the need for external energy sources. We demonstrate a flow system to envisage energy-efficient CO 2 -mediated desalination and simultaneous carbon capture and sequestration.