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Capacitive deionization (CDI) is an alternative to ion exchange resin for removing hardness ions from drinking water, owing to its low energy consumption and minimal liquid waste. However, inappropriate operation of CDI leads to low ion desorption rate (DR) and short service life after prolonged adsorption-desorption cycles. In this study, we systematically controlled the sequence of stagnant stage (S), discharge stage (D), and flush stage (F), as well as the lasting time during each stages of the desorption process, aiming to improve the DR and the stability of CDI. Under fixed water recovery of 70%, the DR of CDI improved significantly from 64% to 89% when the desorption mode changed from S+D→S→F to S→S+D→F. Furthermore, the long-term operation demonstrated a 2.4% lower decay rate with S→S+D→F compared to S+D→S→F. Our findings stress the significance of the desorption mode in desalination, offering insights for CDI manufacturers in future operational design.

Author：趙淑如,蔡明瀚,王鈞逸,林以萱,鐘琍菁,劉柏逸
★Article source：19th IWA Leading Edge Conference on Water and Wastewater Technologies