Commercialization Efforts of Capacitive Deionization Technology in Water Treatment Processes

Although capacitive deionization (CDI) technology has been studied intensively for more than 20 years, its commercialization remains in the initial stage, which is partly caused by the insufficient knowledge exchange between academia and industry. This concept reviews multiple scaling-up efforts in the CDI technology for treating real water streams, following a case-by-case fashion. While the cell architecture in pilot scales is limited to the membrane CDI, highlighting the necessary role of ion-exchange components during scaling-ups, different ways of electrode stacking, i. e., monopolar and bipolar, are available. The performance indicators of these CDI systems when treating real water streams are summarized to gain insights into industrial practices. Importantly, key discrepancies in cell components and performances between pilot-scale and lab-scale studies are emphasized. The main challenges in large-scale CDI systems for industrial purposes are discussed, providing hints for a better integration of research and applications.