Marangoni Effect Drives Salt Crystallization Away from the Distillation Zone for Large-Scale Continuous Solar Passive Desalination
Yang Shao, Anqi Shen, Ningbo Li, Liping Yang, Jiebin Tang, Hui Zhi, Dejuan Wang, Guobin Xue
Abstract
Solar desalination shows great potential in dealing with global water scarcity. A multistage passive solar distiller with thermal localization is especially attractive for its high-water yield. However, achieving long-term stability in large-scale devices remains a challenge because of the easy accumulation of crystallized salt inside the distiller. Here, we reported that the Marangoni effect can drive crystallized salt away along a long distance in a capillary wick, which endow the multistage passive solar distiller with the ability of salt-rejecting. In a 36 h continuous testing, the salinity of the distillation zone is limited below 12 wt % and crystallized salt only accumulates outside the device. The water yield is about 1.7 kg m–2 h–1 in a three-stage device, with a solar-to-vapor conversion efficiency of 114% under one sun. This novel design proves a new principle for high efficiency and long-term stable solar desalination.