Lamellar Wood Sponge with Vertically Aligned Channels for Highly Efficient and Salt-Resistant Solar Desalination

Solar-assistedinterfacial evaporation is a promising approachfor purifying and desalinating water. As a sustainable biomass material,wood has attracted increasing interest as an innovative substratefor solar desalination, owing to its intrinsic porous structure, highhydrophilicity, and low thermal conductivity. However, developingwood-based solar evaporators with high evaporation rates and excellentsalt resistance still remains a significant challenge, owing to theabsence of large pores with high interconnectivity in natural wood.Herein, by converting the honeycombed structure of natural wood intoa lamellar architecture via structural engineering, we develop a flexiblewood sponge with vertically aligned channels for efficient and salt-resistantsolar desalination after surface coating with carbon nanotubes (CNTs).The special lamellar structure with an interlayer distance of 50-300 & mu;m provides the wood sponge with faster water transport, lowerthermal conductivity, and water evaporation enthalpy, thus achievinghigher evaporation performances in comparison with the cellular structureof natural wood. Noteworthy, the vertically aligned channels of thewood sponge facilitate sufficient fluid convection and diffusion andenable efficient salt exchanges between the heating interface andthe underlying bulk water, thus preventing salt accumulation on thesurface. Benefiting from the distinctive lamellar structure, the developedwood-sponge evaporator exhibits exceptional salt resistance even ina hypersaline brine (20 wt %) during continuous 7-day desalinationunder 1 sun irradiation, with a high evaporation rate (1.38-1.43kg m(-2) h(-1)), outperforming mostpreviously reported wood-based evaporators. The lamellar wood spongemay provide a promising strategy for desalinating high-salinity brinesin an efficient manner.