Efficient Water Transport and Solar Steam Generation via Radially, Hierarchically Structured Aerogels.

Abstract

A nature-inspired water-cycling system, akin to trees, to perform effective water and solar energy management for photosynthesis and transpiration is considered to be a promising strategy to solve water scarcity issues globally. However, challenges remain in terms of the relatively low transport rate, short transport distance, and unsatisfactory extraction efficiency. Herein, enlightened by conifer tracheid construction, an efficient water transport and evaporation system composed of a hierarchical structured aerogel is reported. This architecture with radially aligned channels, micron pores, and molecular meshes is realized by applying a radial ice-template method and in situ cryopolymerization technique. This nature-inspired design benefits the aerogel excellent capillary rise performance, realizing a long-distance (>28 cm at 190 min) and quick (>1 cm at 1 s, >9 cm at 300 s) antigravity water transport on a macroscopic scale, regardless of clean water, seawater, sandy groundwater, or dye-including effluent. Furthermore, an efficient water transpiration and collection is performed by the bilayer-structured aerogel with a carbon heat collector on an aerogel top, demonstrating a solar steam generation rate of 2.0 kg m-2 h-1 with the energy conversion efficiency up to 85.7% under one solar illumination. This biomimetic design with the advantage of water transport and evaporation provides a potential approach to realize water purification, regeneration, and desalination.