Rattan-based solar evaporator with natural hierarchical and gradient pore structure for synergetic salt resistance and stable freshwater generation

The solar-driven interface evaporation (SIE) is considered as a potential approach for desalinating seawater and obtaining clean water. However, most reported SIE systems can hardly handle with the accumulating salt crystals. Herein, a new type of SIE device based on surface-carbonized rattan (C-rattan) is presented for high -performance and salt-free desalination. Owing to the hierarchical channels in each vascular bundle and the natural gradient structure of the rattan stem, the C-rattan evaporator can spontaneously generate salinity gradients between and within the vascular bundles that form a synergistic effect to prompt salt exchange and high-salinity solution reflow. In addition to a high water evaporation rate of 1.47 kg m(-2) h(-1) and an efficiency of 90.4% under 1 sun illumination, the C-rattan also presents an outstanding salt resistance ability and an evaporation rate of 1.17 kg m- 2 h(-1) even for the high-salinity brines (20 wt% NaCl solution). Additionally, the C -rattan possesses the self-cleaning ability that enables it to clear off extra added salt during the solar desalination process. Considering its low-cost and sustainable raw materials, simple preparation procedures, long-term salt resistance ability and self-cleaning capacity, the C-rattan-based SIE device holds a great promise for people living in developing regions to obtain drinkable water from seawater or high-salinity brine.

Automated summary

This study presents a new type of solar-driven interface evaporation (SIE) device based on surface-carbonized rattan (C-rattan) for high-performance and salt-free desalination. The C-rattan evaporator can generate salinity gradients to prompt salt exchange and high-salinity solution reflow. It demonstrates a high water evaporation rate, salt resistance ability, and self-cleaning capacity, making it promising for obtaining drinkable water from seawater in developing regions.