Full Biomass-Derived Solar Stills for Robust and Stable Evaporation To Collect Clean Water from Various Water-Bearing Media.

Solar steam generation is considered to be a promising strategy for sustainable clean water supply. An easily made and robust solar still can practically meet any contingency in wilderness survival, compared to high-cost and delicate solar thermal materials, for example, plasmonic metals, carbon nanotubes, or graphene-based materials. Inspired by rice plants with high transpiration, we develop a universal solar steam-generation device from wasted rice straw for robust clean water production. The upper leaves of rice straw are carbonized and composited with bacterial cellulose to function as a superior light absorber and the lower culms are designed as excellent water pumps. The unique capillary structures and multilevel geometrical structures of the rice culms contribute to their outstanding water pumping capacity for surface evaporation, resulting in an evaporation rate of 1.2 kg m h with 75.8% conversion efficiency. The rice straw-derived solar still has a daily clean water yield of 6.4-7.9 kg m on sunny days and 4.6-5.6 kg m on cloudy days over 14 days of operation. More attention-grabbing aspect is that this evaporation device is applicable to various water-bearing media, for example, sand, soil, and seawater, to collect clean water with a stable evaporation performance, and the unique multilevel structures of the culms make great contribution to the unimpeded water channels. By turning "waste" to "wealth," this project shines significant light on a facilely fabricated, robust, and efficient solar still, especially designed for urgent priority in wilderness survival.