Dual‐Biomimetic Solar Evaporator for Simultaneous Freshwater Production, Salt Harvesting, and Oil Recovery From Oily Seawater

Abstract

Solar‐driven interfacial evaporation has emerged as a sustainable and promising technology for seawater desalination, but its practical deployment is severely hindered by the ubiquitous presence of oil contamination in marine environments. Here, a hierarchical evaporator (GSPMS) was developed to achieve the simultaneous recovery of freshwater, solid salts, and oil. In the design, a mangrove‐inspired hydrophilic sponge (GSMS) ensures continuous capillary water transport and directs salt crystallization in predefined regions, while a Salvinia‐inspired hydrophobic‐oleophilic sponge (GPMS) selectively captures oil droplets and continuously expels them through capillary‐assisted siphon transport. Consequently, the GSPMS exhibits a stable evaporation rate of 3.43 kg m −2 h −1 along with a salt harvesting rate of 165.8 g m −2 h −1 over 50 h of continuous operation in 20 wt% brine. For seawater containing 20 vol% oil, the evaporator also delivers an evaporation rate of 4.11 kg m −2 h −1 and an oil recovery of 97.73%, while maintaining a separation efficiency above 99% over 10 cycles. This dual‐bioinspired strategy offers a promising strategy toward zero liquid discharge desalination and the comprehensive utilization of seawater resources, highlighting the potential of integrated multi‐resource recovery in solar‐driven water treatment.