Water adsorption isotherms from 25 to 125 °C were measured for three metal–organic frameworks (MOFs), MOF-303, MOF-LA2-1, and MIL-100(Fe), which are frequently studied for water harvesting applications. The results show how the step in the water adsorption isotherm varies as a function of temperature and detail the combination of pressure and temperature necessary to remove adsorbed water. Furthermore, isobaric–isothermal Gibbs ensemble Monte Carlo simulations performed for MOF-303 shed light on the change in occupation numbers of the different known water adsorption sites with increasing temperature. Additionally, the diffusion rates of water through these materials were measured using concentration swing frequency response, and micropore diffusion was identified as the controlling mechanism. The Darken relation was used to show the dependence of the diffusion rate on the concentration and the impact of the adsorption isotherm slope. The adsorption of water on MOF-LA2-1 is faster than that on MIL-100(Fe). These data show that MOF-LA2-1 with its high-water adsorption capacity, quick adsorption rate, and favorable desorption energetics is a leading candidate for atmospheric water harvesting.

中文翻译：

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集水金属有机框架的高温水吸附等温线和环境温度水扩散速率


测量了三种金属有机框架 (MOF)：MOF-303、MOF-LA2-1 和 MIL-100(Fe) 的 25 至 125 °C 范围内的水吸附等温线，这些材料经常被研究用于水收集应用。结果显示了水吸附等温线的阶跃如何随温度变化，并详细说明了去除吸附水所需的压力和温度的组合。此外，对 MOF-303 进行的等压-等温吉布斯系综蒙特卡罗模拟揭示了不同已知水吸附位点的占据数量随温度升高的变化。此外，使用浓度摆频响应测量水通过这些材料的扩散速率，并将微孔扩散确定为控制机制。达肯关系用于显示扩散速率对浓度的依赖性以及吸附等温线斜率的影响。 MOF-LA2-1 上的水吸附速度比 MIL-100(Fe) 上的吸附速度快。这些数据表明，MOF-LA2-1 具有高水吸附能力、快速吸附速率和良好的解吸能量，是大气水收集的主要候选材料。