Advanced Strategies of Salt Blocking in the Hypersaline Water

In the past decade, due to high consumption of freshwater and severe drought on the earth, human beings have experienced an unprecedented freshwater crisis. Solar-driven desalination assisted by photothermal conversion materials is a new technology that mitigates the shortage of clean water in a green way. In this review, six advanced strategies have been discussed, which are the hydrophobic effect, unidirectional brine transport, zwitterionic effect, edge crystallization, siphon capillary effect, and dissolution-based salt migration to avoid salt scaling in hypersaline water systems. We greatly expanded the mechanistic understanding of these approaches by studying major phenomena such as wettability, capillary flow, concentration-gradient-driven back-diffusion, Marangoni flow, Donnan exclusion, and hydration-layer effects. Finally, we proposed future research directions from a scientific perspective to direct the field and encourage practical implementation. In particular, we propose to develop multiscale porous structures combining edge crystallization with unidirectional transport for balanced water supply, evaporation, and salt removal. These systems could extract valuable mineral resources and freshwater from seawater simultaneously.