Tree-Inspired Aerogel with a Radial and Centrosymmetric Structure for Efficient Solar-Powered Water Purification

Solar-powered water purification is one of the promising choices for clean water production. However, it remains challenging to develop aerogel solar evaporators that simultaneously possess enhanced light-to-heat conversion, optimal thermal management, and salt crystal deposition inhibition. Herein, to address this challenge, we have developed a 3D chitosan-reduced graphene oxide/polypyrrole (CS-RGO/PPy) aerogel vaporizer with a vertical and radially aligned structure through a directional freezing process, inspired by the featured structure of conifers. The radially porous walls and vertically arranged channels within the 3D aerogel were able to facilitate high light absorption, localizing converted heat, rapid water transport, and self-salt discharge. Under 1 sun irradiation, the aerogel vaporizer displayed an improved light absorption characteristic of 95% and a high-rate evaporation (∼3.19 kg m-2 h-1) that achieved continuous freshwater from the saturated brine production without solid salt crystallization. Besides achieving seawater desalination, the obtained aerogel could purify organic wastewater and emulsions through solar distillation with high-rate continuous water production.