Herein, we introduce a series of ionic covalent organic frameworks (iCOFs) with a focus on addressing the challenge of water collection at low relative humidity levels below 25%. These iCOFs are characterized by numerous hydrophilic sites and high water stability, enabling efficient water vapor adsorption even at relatively low humidity levels. Through the use of various hygroscopic salt cations and precise control of ion concentration within the pores, the water state within the iCOFs pores can be effectively managed. Among the iCOFs, TB‐COF‐Li stands out with an impressive adsorption capacity of 0.24 g g‐1 from 0 to 22% RH. Notably, due to its ionic porous structure, TB‐COF‐Li exhibits a significantly lower enthalpy of evaporation, measured at 967.04 J g‐1, compared to bulk water with an enthalpy of 2387.4 J g‐1. Moreover, under simulated conditions of 1.5 solar intensity at 60 °C, the majority of the adsorbed water can be rapidly desorbed without the need for additional energy input. This efficient desorption process contributes to a high water collection rate of 0.092 g g‐1 h‐1 in the final atmospheric water harvesting device. The development of these iCOFs offers a promising and cost‐effective solution for obtaining fresh water in arid regions.

中文翻译：

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低蒸发焓离子共价有机框架，可在低湿度下高效收集大气中的水


在本文中，我们介绍了一系列离子共价有机框架 （iCOF），重点是解决在低于 25% 的低相对湿度水平下收集水的挑战。这些 iCOF 的特点是具有许多亲水位点和高水稳定性，即使在相对较低的湿度水平下也能实现高效的水蒸气吸附。通过使用各种吸湿性盐阳离子和精确控制孔隙内的离子浓度，可以有效地管理 iCOF 孔隙内的水状态。在 iCOF 中，TB-COF-Li 在 0% 至 22% RH 下的吸附能力高达 0.24 g g-1，令人印象深刻。值得注意的是，由于其离子多孔结构，TB-COF-Li 的蒸发焓明显较低，测得为 967.04 J g-1，而本体水的焓为 2387.4 J g-1。此外，在 60 °C 下 1.5 太阳强度的模拟条件下，大部分吸附的水可以快速解吸，而无需额外的能量输入。这种高效的解吸过程有助于在最终的大气水收集装置中实现 0.092 g g-1 h-1 的高水收集率。这些 iCOF 的开发为干旱地区获取淡水提供了一种有前途且具有成本效益的解决方案。