One of the main trends in the development of solar interface evaporation technology is the simple, efficient, and environmentally friendly bio-based evaporation device. However, the development of bio-based evaporators with high water evaporation rates and good pollution removal capability is a significant challenge. Here, we present a carbonized cattail-agarose hydrogel (CCAH) membrane with numerous microchannels resembling bamboo knots, exceptional hydrophilicity, outstanding light absorption capability, and potent adsorption. Under one solar irradiation, its evaporation rate and efficiency reached 1.93 kg m-2 h-1 and 95.8%, respectively. More importantly, the CCAH membrane produces steam water that is almost totally free of salts (Na+, K+, Mg2+, and Ca2+), heavy metal ions (Pb2+, Cd2+, and Cr2+), and organic dyes (Rhodamine B, methylene blue, and methyl orange). The CCAH membrane is highly promising for the use of saltwater desalination and wastewater recovery to help people in impoverished areas with water scarcity problems.
Keywords: carbonized cattail; hydrogel; seawater desalination; solar water evaporation; wastewater purification.