https://doi.org/10.1002/solr.202300026
Abstract：Solar-driven steam generation is considered one of
the most promising techniques to obtain freshwater. Under the same projection
area, 3D evaporator has a larger evaporation area and can get more energy from
the environment, resulting into better evaporation performance. 3D evaporators are often hindered by complex and dangerous
fabrication process, special and expensive equipment, and costly raw materials. Herein, we propose a simple method
to prepare a low-cost and highly efficient 3D solar evaporator using chalk and ink that are common in
classrooms. This method does not involve expensive raw materials and
any equipment, and the manufacturing process is simple and fast, especially
suitable for less developed regions. Thanks
to the excellent hydrophilicity of chalk and the strong sunlight absorption of
black ink, the ink-stained chalk (ISC)
shows up to 20.49 kg m-2 h-1 of the evaporation rate under one sun
illumination. When treating real seawater sample, ISC prepared from
broken or used chalks show highly efficient (8.97-19.91 kg m-2 h-1) and stable (24 h)
solar desalination. The ink-stained
chalk presented in this work
offers a new avenue to develop 3D solar evaporator for
low-cost and high-efficient seawater desalination, which is especially attractive for
remote and less developed areas.