Advanced solar desalination on superwetting surfaces

Abstract

Solar desalination separates freshwater and salt from brine by utilizing solar energy, which is an ideal solution to the global water crisis. Among all parts of a solar-evaporator, the brine–solid interface is the central element where major events, including water evaporation, salt crystal nucleation, brine wetting, de-wetting, etc., take place. Surface wettability of solar evaporators plays a leading role in enhancing energy conversion efficiency, as it governs many key factors including water spreading, transport, evaporation, salt adhesion, etc. In this review, we establish the correlation between surface wettability and the multiple solar desalination processes, i.e., mobility of the three-phase contact line, salt crystal nucleation and growth dynamics, liquid/salt/vapor transport path, droplet nucleation and growth, etc. Recent highlights on super wettability-empowered highly efficient solar desalination systems are also discussed. Finally, existing challenges and future opportunities in efficient, continuous, and industrial-scale desalination systems based on super wettability are outlooked.