Gel-based evaporators for solar desalination of high concentration brines

Interfacial solar evaporation has gained attention in seawater desalination and wastewater treatment due to its high efficiency, environmental sustainability, and low cost. However, salt buildup on the evaporator surface, clogging water transport channel and reduction in effective evaporation area result in decreased evaporation performance. Notably, reducing the salt accumulation of evaporators through strategies such as surface engineering, hierarchical structures, and capillary-driven designing is vital to achieving high solar-to-vapor energy conversion efficiency and optimizing long-term stability. This review explores the salt management and desalination stability of gel-based evaporators for solar desalination of high concentration brines. Improving the stability of the desalination process is suggested by refining the hierarchical structures engineering of the gel-based evaporator, modifying the surface wetting characteristics (hydrophilicity/hydrophobicity), and choosing an appropriate polyelectrolyte to efficiently regulate salt deposition on the surface. Furthermore, the review highlights opportunities and outlines key considerations for the practical application of gel-based evaporators.