Abstract Capacitive deionization (CDI) and membrane capacitive deionization (MCDI) are widely considered as promising, highly energy efficient processes for water desalination, of which commonly used performance indicators are the average salt adsorption rate, the salt removal efficiency, and the charge efficiency. Quantification of the sustainability performance of CDI and MCDI is still scarce, and in this paper, we use exergy analysis to evaluate the resource use efficiency of membrane capacitive deionization (MCDI). The electric as well as chemical exergies of the salt solution, and the stored ions, are used to calculate the exergy efficiency (ηex) and cumulative exergy losses (CEL) ranging between 2 to 13% and 0.5 to 8 J/mol water, respectively. From an exergetic point of view, passive adsorption in combination with active desorption (−0.9 V) is favorable, yielding the highest ηex and lowest CEL values. The combination of active salt adsorption using an electric field, with either passive or active desorption gives higher productivities, but at the cost of a disproportionate amount of exergy (and energy) input.

中文翻译：

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膜电容去离子 (MCDI) 的火用分析

摘要 电容去离子（CDI）和膜电容去离子（MCDI）被广泛认为是有前景的、高能效的海水淡化工艺，其常用的性能指标是平均盐吸附率、除盐效率和充电效率。CDI 和 MCDI 可持续性性能的量化仍然缺乏，在本文中，我们使用火用分析来评估膜电容去离子（MCDI）的资源利用效率。盐溶液的电和化学能以及储存的离子用于计算火用效率 (ηex) 和累积火用损失 (CEL)，范围分别为 2 至 13% 和 0.5 至 8 J/mol 水. 从热能的角度来看，被动吸附结合主动解吸（-0. 9 V) 是有利的，产生最高的 ηex 和最低的 CEL 值。使用电场的主动盐吸附与被动或主动解吸相结合可提供更高的生产率，但以不成比例的火用（和能量）输入为代价。