Membrane distillation (MD) is emerging as an important desalination technology that can operate at relatively low temperatures and can handle high salt concentrations. In this Article, we present microwave-induced membrane distillation (MIMD) where microwave radiation is used to heat the saline water for MD. Pure water vapor flux from MIMD was compared to that generated by conventional heating, and the enhancement reached as high as 52%. Because of the higher dielectric constants, flux enhancement was more significant at high salinity, and the mass transfer coefficient at 150 000 ppm was found to be nearly 99% higher than what was observed under conventional heating. Performance enhancement in MIMD was attributed to nonthermal effects such as the generation of nanobubbles, localized superheating, and breaking down of the hydrogen-bonded salt–water clusters. These effects were investigated using FTIR, ion mobility measurements, and dynamic light scattering. In addition, microwave heating consumed nearly 20% less energy to heat water to the same temperature. The combination of energy savings and higher flux represents a significant advancement over the state of the art for MD.

中文翻译：

---

通过直接接触膜蒸馏进行微波诱导的脱盐

膜蒸馏（MD）作为一种重要的脱盐技术正在兴起，该技术可以在相对较低的温度下运行并且可以处理高盐浓度。在本文中，我们介绍了微波诱导膜蒸馏（MIMD），其中微波辐射用于加热盐水以形成MD。将来自MIMD的纯净水蒸气通量与常规加热产生的通量进行了比较，其增强率高达52％。由于较高的介电常数，在高盐度下通量增强更为显着，并且发现在150000 ppm处的传质系数比常规加热下的传质系数高近99％。MIMD的性能增强归因于非热效应，例如纳米气泡的产生，局部过热，并破坏了与氢键结合的咸水团簇。使用FTIR，离子迁移率测量和动态光散射研究了这些效应。此外，微波加热将水加热到相同温度所消耗的能量减少了近20％。节能和高通量的结合代表了MD领域最先进的进步。