A 3D Janus-like structure evaporator based on capillary force promoting efficient solar steam generation

Abstract

The interface of evaporation driven by solar energy has received widespread attention as a promising seawater desalination technology to solve the crisis of freshwater shortage. However, the extensive precipitation of salt during seawater desalination process limits the application of solar evaporators. Herein, a method is proposed to obtain a three-dimensional (3D) evaporator with Janus structure by impregnating wood flowers (WFs) with ink. The advantage of the evaporator with Janus structure is that it can effectively suppress salt precipitation during the evaporation process. From the scanned electronic image, it can be seen that some flocculent substances inside the evaporator have been thoroughly cleaned, preserving the complete pore structure. From the evaporation tests under different light intensities, it can be seen that the optimal evaporation rate occurs at a specific solar intensity, as its surface temperature reaches the temperature required for optimal evaporation. The distribution of salt particles in the evaporator after evaporation is due to the large temperature difference between the top and bottom of the evaporator, resulting in different hydrophilic effects at the top and bottom, ultimately achieving a Janus-like effect. Salt particles are evenly distributed in strips on both sides in the middle. The advantage of this distribution is that it preserves as much evaporation area as possible, thereby achieving stable and effective evaporation. This experiment provides some ideas for the development of 3D Janus evaporators and the formation principle of Janus structures.