Several water/salt separation processes are currently being developed to employ sunlight for sustainable water desalination. Here, we report a redox flow process for solar desalination of brackish water, which integrated a redox flow desalination (RFD) system with an aqueous dye-sensitized solar cell (DSSC). The use of an iodide/triiodide redox electrolyte mediated light-to-electricity conversion at the photoanode and salt separation across ion-exchange membranes at relatively low voltages (< 0.5 V). The solar RFD process produced freshwater ([NaCl] < 1 g L^–1) continuously from a 50-mM feed solution at 10.3 LMH productivity (L-freshwater m^–2-area h^–1) that increased to 28.8 LMH for a 20-mM feed solution. The process current efficiency was in the range of 73 ± 7%. The nonsolar RFD mode produced freshwater at a productivity of 41.1 LMH, energy consumption of 0.42 kWh m^–3, and current efficiency of about 80%. Correlations derived for predicting the extent of salt removal for the different process parameters of the solar and nonsolar RFD processes indicated that the DSSC photocurrent is a critical factor for increasing freshwater productivity in the solar RFD mode. With further improvements in water-compatible photoanodes and redox electrolytes, the solar RFD could present a viable and sustainable approach for water desalination.

中文翻译：

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通过整体集成氧化还原流动装置对苦咸水进行连续太阳能脱盐

目前正在开发几种水/盐分离工艺，以利用阳光进行可持续的海水淡化。在这里，我们报告了一种用于微咸水太阳能淡化的氧化还原流工艺，该工艺将氧化还原流淡化 (RFD) 系统与水性染料敏化太阳能电池 (DSSC) 集成在一起。使用碘化物/三碘化物氧化还原电解质在相对低的电压 ( < 0.5 V) 下介导光电阳极处的光电转换和离子交换膜上的盐分离。太阳能RFD方法生产淡水（[氯化钠] < 1克L- ^-1）连续地从在10.3 LMH生产率（L-淡水米有50 mM的进料溶液^-2 -面积ħ ^-1) 对于 20 mM 进料溶液，增加到 28.8 LMH。工艺电流效率在 73 ± 7% 的范围内。非太阳能 RFD 模式以 41.1 LMH 的生产力、0.42 kWh m ^{–3 的}能耗和约 80% 的电流效率生产淡水。用于预测太阳能和非太阳能 RFD 过程的不同工艺参数的脱盐程度的相关性表明，DSSC 光电流是在太阳能 RFD 模式下提高淡水生产力的关键因素。随着与水相容的光阳极和氧化还原电解质的进一步改进，太阳能 RFD 可以提供一种可行且可持续的海水淡化方法。