Bamboo shoot inspired ultra-high conical porous evaporator for desalination of seawater with high salinity

Abstract

Solar-driven seawater evaporation is sustainable for freshwater but limited by water sources, wastes tolerance, and durability. Here, we propose a bamboo shoot inspired conical porous evaporation made of multiwall carbon nanotube-based composite materials, which demonstrates ultra-high-water transportation, high evaporation efficiency and salt-rejecting properties under high salinity and contaminated conditions. Its bioinspired microchannels’ capillary effect can drive liquid up to 126.0 mm, offering continuous water supply for evaporation and reducing liquid surface pressure, thus increasing evaporation efficiency with a capacity up to 2.54 kg m^-2h⁻¹. Meanwhile, the three-dimensional structure generates a temperature gradient, which induces Marangoni convection and facilitates the flow of saline water from high-concentration areas to low-concentration areas. This convection and capillary fluid replenishment work together to maintain salt concentration balance, enabling long-term seawater desalination over 200 h in 20 wt% saline water without cleaning.