Duckweeds mimicked self-clean Janus solar evaporator

Solar water evaporation has been considered as a promising method to solve the global water scarcity due to its low energy consumption, environmental friendly, as well as high water evaporation efficiency. However, salt crystallization on evaporation surface drastically decrease the evaporation rate of seawater. In this work, we propose a novel bionic solar evaporation system based on 3D printing technology inspired by natural duckweeds. Water can be easily transported to the evaporation surface through regularly arranged "S" shaped microchannels. Superhydrophilic surface enables the water spread quickly on evaporation surface and eventually fall back to bulk water, realizing the self-clean capability. The evaporation rate of our solar evaporation system can reach up to 1.40 kg m−2 h−1 with an evaporation efficiency of 95.7% under 1 sun irradiation. In addition, the evaporator demonstrates amazing desalination and purification capabilities, which can effectively remove metal ions as well as organic impurities with a purification rate up to 99.9%. Moreover, long-term desalination performance of our evaporation system has been well achieved, demonstrating the effective and stable performance of our bionic evaporation system for seawater desalination.