膜蒸馏脱盐过程膜润湿的研究进展

膜蒸馏（MD）适合在偏远地区小规模制备淡水，有脱盐率高、接近常压操作、可利用太阳能等优势。但MD膜润湿影响了装置的运行稳定性，是制约MD脱盐应用的重要因素之一。本文介绍了MD膜润湿的评价方法，包括测定透水压力、临界膜孔润湿深度及可视化在线监测膜润湿进程等；简述了膜污染、MD操作变量、膜蒸馏形式及不同结垢晶体各因素对膜润湿的影响；从防垢和强化通量、掌握合适的膜清洗周期、物理干预及提升MD膜性能等方面分析了抑制膜润湿的措施；并分析了一些脱盐实验时间较长的MD膜润湿情况；指出具有自清洁性的光催化膜及防垢性能更强的双疏膜和Janus膜，具有抑制MD膜润湿的巨大潜力。本文有助于对脱盐过程中MD膜润湿的预测和有效控制。

Progress of research on membrane wetting in membrane distillation desalination

Membrane distillation (MD) is suitable for small scale production of fresh water in remote areas with the advantages of high salt rejection rate, nearly atmosphere operation, utilization of the solar energy and so on. However, membrane wetting affects the operation stability of MD device which is a major factor of restricting the application of MD desalination. The evaluation methods of MD membrane wetting, including the measurement of liquid entry pressure (LEP), critical membrane pore wetting depth and in-situ observation of membrane wetting process and so on, were introduced firstly. Then, the influenced factors on membrane wetting such as membrane fouling, MD operating variables, various MD configurations and distinct scaling behaviors were discussed in details. The inhibition measures of membrane wetting were analyzed from several aspects, such as anti-fouling, enhancing flux, suitable membrane cleaning period, physical methods and improving the performances of membrane. Finally, the behaviors of membrane wetting during the course of the long-term MD desalination operation were also introduced. It was pointed out that photocatalytic composite membrane with self-cleaning property, omniphobic membrane and Janus membranes were of great potential to prevent membrane wetting and probably applied in anti-wetting MD membrane. The studies in this paper will be helpful to predict and control MD membrane wetting during desalination.