Tilted 3D evaporator with high-performance salt rejection for seawater desalination

Salt accumulation severely impacts the performance of solar desalination systems and hinders their long-term application in practice. Herein, we report a tilted 3D evaporator with high-performance salt-rejecting feature based on carbon nanodots (CDs)/luffa composite. The tilted 3D evaporator was designed by immersing one edge of CDs/luffa composite in a seawater tank and tilting at an angle to the horizontal plane. Upon solar irradiation, seawater was transferred through CDs/luffa composite at the bottom surface and wicked to the top surface for evaporation. Meanwhile, salt at the top surface was rejected back to the bottom surface and further taken away from the evaporator by the flowing seawater, thus avoiding salt accumulation for long-term solar desalination. Furthermore, the evaporator demonstrated effective thermal localization and absorption of environmental energy, possessing high evaporation rates of 2.05 and 1.50 kg m−2 h−1 when evaporation with water and real seawater, respectively (under one sun irradiation). Our study provides a promising strategy for salt rejection and enhancing the performance of solar desalination in practice.