Solar Evaporators for Saline Water: Sustainable Clean Water Harvesting and Critical Mineral Resources Extraction

Solar-driven interfacial water evaporation (SIWE) can efficiently utilize solar energy to separate or extract various ions from saline water, providing an environmentally friendly, economical, and sustainable approach to clean water and critical mineral resources harvesting. However, for ongoing practical implementation, solid salt accumulation at the interface will inevitably impair the SIWE performance, while direct disposal of residual concentrated brine poses significant environmental risks. As such, advancing solar evaporators for sustainable clean water harvesting and critical mineral resources extraction is pivotal in the resources-energy-environment nexus. Critically, this review spotlights the latest research progress in engineering nonselective salt-rejecting solar evaporators (NS-SRSEs) for sustainable desalination, emphasizing interfacial structural design and surface modification. We then delineate our endeavors aimed at the construction strategies of selective salt-extraction solar evaporators (S-SESEs) for getting access to critical mineral resources such as uranium and lithium. Finally, current challenges and opportunities are outlined in the high-value saline water utilization of NS-SRSE and S-SESE for real-world applications that balance high efficiency, durability, and adaptability with a low environmental impact. Looking ahead, we anticipate ongoing advancements in promoting solar evaporators from laboratory research to practical applications, contributing to global efforts in sustainable water management and critical mineral resources recovery.