Salt solutions have attracted significant interest as water sorbents for a wide range of applications due to their large hygroscopicity and low cost. However, despite their promise, no existing model fully describes the experimentally observed absorption and desorption behavior of salts. Here, we develop a model that accurately captures absorption and desorption of water vapor into salt solutions. Our results show that the nonlinear driving force due to the chemical activity of water leads to previously unexplained behaviors such as faster desorption than absorption and absorption-rate dependence on humidity. We leverage our model to demonstrate the trade-off of uptake and sorption time as the humidity and salt type are changed and show the dependence of the timescale on the system’s parameters. This model represents a fundamental advancement in the understanding of salt solution absorption-desorption and supports the optimization of water sorption applications.

盐溶液作为吸水剂，由于其吸湿性大且成本低而引起了广泛应用的广泛关注。然而，尽管有希望，但现有的模型还没有完全描述实验观察到的盐的吸收和解吸行为。在这里，我们开发了一个模型，可以准确捕获水蒸气在盐溶液中的吸收和解吸。我们的结果表明，由于水的化学活性而产生的非线性驱动力会导致以前无法解释的行为，例如解吸速度快于吸收速度以及吸收率对湿度的依赖性。我们利用我们的模型来演示随着湿度和盐类型的变化吸收和吸附时间的权衡，并显示时间尺度对系统参数的依赖性。该模型代表了对盐溶液吸收-解吸的理解的根本进步，并支持水吸附应用的优化。