All Natural, High Efficient Groundwater Extraction via Solar Steam/Vapor Generation

Abstract Solar steam/vapor generation is a promising approach to produce clean water and solve water scarcity and energy shortage issues. Most of steam/vapor generation devices can only be used on surface water from oceans, lakes, or rivers. Groundwater is another essential resource for public water supply. Acquiring clean water directly from groundwater is important, especially for countries and regions that lack surface water. A natural, plant‐inspired solar steam/vapor generation device is developed in this work by coating a thin layer of carbon nanotubes (CNTs) on the top surface of a tree stump with roots to extract water directly from groundwater. The 3D interconnected channels/pores in the roots and stump enable fast water transportation within the plant. Under sunlight irradiation, the surface‐coated CNT layer can convert solar energy into heat, and the water is continuously supplied to the heat‐localized interfacial layer of the top surface and is evaporated into vapor upon heating. The evaporation efficiency of such steam/vapor evaporation device for extracting water from groundwater is as high as ≈86% under 10 kW m −2 , which approaches the best performance achieved by devices for surface water extraction, providing an attractive method to utilize groundwater.