A self-standing and self-floating 3D cavity evaporator for highly efficient desalination and wastewater treatment

Interfacial solar desalination has been widely considered as a promising technology for fresh water production because of its green, pollution-free and sustainable characteristics. Compared with the 2D solar evaporator, the 3D solar evaporator has a larger evaporation area. But traditional 3D evaporators could not utilize solar energy effectively due to its inefficient internal and peripheral spaces. Consequently, based on silk cocoon shell and its natural cavity structure, a 3D solar evaporator with internal and external double evaporation interface was designed and manufactured in this paper. The prepared evaporator had double evaporation surfaces which increased the actual evaporation area and the conversion efficiency of solar energy. Besides, the evaporator of Up-FSCE exhibited excellent thermal management performance, its evaporation rate reached 2.32 kg m−2 h−1 under 1 sun illumination. This study offers new insights into the structural design of 3D solar evaporators and further promotes the practical application of interfacial solar desalination.