Low-energy desalination technologies capable of continuous throughput at reasonable operating and maintenance cost are now critically needed. Herein, we present a continuous desalination process with average energy consumption as low as 2.14 kJ mole⁻¹ salt removed achievable when using a 10 mM/10 mM ferri-/ferrocyanide solution that flows continuously between anode and cathode chambers. The salt feed at ∼3000 ppm can be continuously desalted to a potable level of less than 150 ppm during the desalination process. At the anode, ferrocyanide is oxidized with electrons released to the external circuit and cations captured to achieve charge balance. Ferricyanide is reduced at the cathode, resulting in the constant transfer of anions from the dilute stream to the concentrate stream. The recycling of the redox mediators maintains an extremely low operating potential (∼100 mV) and continuous salt extraction with unlimited removal capacity. Comparison of the use of ferri-/ferrocyanide, pure ferricyanide and ferrocyanide solutions indicate that the ultra-low energy consumption can be ascribed to the excellent electrochemical properties of the ferri-/ferrocyanide couple and the extremely low overpotential of the redox reactions owing to the synergistic effect of sufficient simultaneous ferrocyanide oxidation and ferricyanide reduction in the flow electrolyte streams. Our research provides a route for ultra-low energy desalination based on voltage suppression via use of facile redox couple mediators.

现在迫切需要能够以合理的运行和维护成本实现连续生产的低能耗淡化技术。在此，我们提出了一种连续脱盐工艺，平均能耗低至2.14 kJ mole ^-1当使用在阳极室和阴极室之间连续流动的10 mM / 10 mM亚铁/亚铁氰化物溶液时，可以去除盐。在脱盐过程中，约3000 ppm的盐进料可以连续脱盐至小于150 ppm的可食用水平。在阳极，亚铁氰化物被释放到外部电路的电子氧化，并捕获阳离子以实现电荷平衡。铁氰化物在阴极被还原，导致阴离子从稀释流向浓缩流不断转移。氧化还原介体的循环可保持极低的工作电势（〜100 mV），并具有无限去除能力的连续盐提取。比较亚铁氰化物/亚铁氰化物的用途，纯亚铁氰化物和亚铁氰化物溶液表明，超低能耗可归因于亚铁氰化物/亚铁氰化物对的出色电化学性能和氧化还原反应的极低过电位，这归因于亚铁氰化物同时充分氧化和铁氰化物还原的协同作用在流动的电解液中。我们的研究提供了一种通过使用简便的氧化还原对介体，基于电压抑制的超低能量脱盐途径。