Loofah Sponge-Derived Hygroscopic Photothermal Absorber for All-Weather Atmospheric Water Harvesting

The loofah gourd is like a natural water tank that stores underground water and drains it out after aging, leaving only a three-dimensional network consisting of hollow and interconnected fibers. This phenomenon inspired us to fabricate a solar-energy-powered sorption-based atmospheric water harvesting device using a loofah sponge. Herein, moisture absorption and photothermal conversion strategies are rationally designed to fast release the absorbed water. This is accomplished by filling the hollow and connected loofah fiber with LiCl and replacing the original luffa peel with a bacterial cellulose (BC)/carbon nanotube (CNT) photothermal conversion membrane. As a result, loofah/BC/CNT (LBC)@LiCl presents a high water absorption capacity of 2.65 g g–1 at 90% relative humidity (RH) and fast water release performance of 1.33 kg m–2 h–1 under 1.0 sun. Noticeably, ∼1.92–2.40 kg LBC@LiCl can produce daily drinking water for adults (2000–2500 mL) in one night outdoors at ∼66% RH, proving that it is a feasible method to overcome the drinking water shortage of poor and arid areas using cheap and renewable biomass material.