Flow electrode capacitive deionization (FCDI) holds great advantage and potential compared with conventional CDI as it enables continuously water desalination. However, efficient electrode separation to prevent its runoff is a great challenge that has not been well addressed. In this study, we demonstrated an FCDI process tailored for ion electrosorption using magnetic activated carbons (MACs) synthesized by simple coprecipitation of Fe₃O₄ on carbon substrate. The Fe₃O₄ provides the magnetism necessary for magnetic separation, while the carbon substrate endows electrosorption sites for ions. When used as electrodes in desalination cycles, the MACs exhibit similar salt removal rate with bare activated carbon but extremely high charge efficiency (>100%) and energy efficiency because of enhanced interparticle aggregation increasing electric conductivity and causing charge imbalance in the electrode chambers. The MAC also exhibited excellent magnetic separation efficiency (>99.81%) with its half retention lifetime 2 orders of magnitude higher than activated carbon and high stability with a lifetime of thousands of cycles. This study provides an easy and “contactless” separation of the fluidized electrodes in the FCDI system, which is safe and friendly for FCDI operation and maintenance in practical application.

中文翻译：

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在流动电极电容去离子中利用磁性碳提高电荷效率和电极分离

与传统的CDI相比，流电极电容去离子（FCDI）具有巨大的优势和潜力，因为它可以连续进行水脱盐。然而，有效的电极分离以防止其径流是一个巨大的挑战，尚未得到很好的解决。在这项研究中，我们展示了一种专为离子电吸附而设计的FCDI工艺，该工艺使用通过在碳基质上简单共沉淀Fe ₃ O ₄合成的磁性活性炭（MAC）进行。铁₃ O ₄提供碳分离所需的磁性，而碳基质赋予离子电吸附位。当在脱盐循环中用作电极时，MAC表现出与裸露的活性炭相似的除盐率，但是由于增强的颗粒间聚集，提高了电导率并导致电极室中的电荷失衡，因此具有极高的电荷效率（> 100％）和能量效率。MAC还表现出出色的磁分离效率（> 99.81％），其半保留寿命比活性炭高2个数量级，并且具有数千次循环的高稳定性。这项研究为FCDI系统中的流化电极提供了一种简单而又“无接触”的分离方式，在实际应用中对于FCDI操作和维护是安全和友好的。