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

Abstract

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 solarenergy-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.

Hygroscopic and Photothermal All-Polymer Foams for Efficient Atmospheric Water Harvesting, Passive Humidity Management, and Protective Packaging

“…Although some powder and liquid desiccants (i.e., hygroscopic salts, silica gel, zeolite, and glycerin) have been used for conventional sorption-based dehumidification, there are significant challenges in developing bulk desiccants with tailorable structures, stable water adsorption/desorption, and low energy input for regeneration. − The incorporation of organic/inorganic hybrid desiccants within porous three-dimensional (3D) scaffolds is of particular interest, enabling the development of hybrid desiccants with multidimensional shapes (i.e., fabrics, gels, membranes, aerogels, hydrogels, and foams). − Emerging desiccants based on metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) have shown rapid water vapor adsorption and desorption. − It is noted that 3D hybrid desiccants can release water and become regenerated via low-grade thermal energy intake (i.e., waste heat and solar energy) with the help of photothermal or radiative cooling materials, minimizing the carbon footprints of air conditioning. − The reversible water uptake/release and good long-term stability provide a potential avenue for using 3D hybrid desiccants as indoor humidity regulators compared to conventional humidifiers (i.e., based on evaporation and steam) and dehumidifiers (i.e., based on air conditioning and refrigeration). − …”

Phospholipid Bilayer Inspired Sandwich Structural Nanofibrous Membrane for Selective Water Harvesting and Release

“…Owing to the strong capillary force of the micropores, the salt solution would be con ned in the carriers. 33 However, the con ned pore size limited its water uptake ability. The salt solution would leak again when the carriers were exposed to a moist environment for a long time where the captured water was too much to be stored inside the pores.…”

Marine biomass-derived, hygroscopic and temperature-responsive hydrogel beads for atmospheric water harvesting and solar-powered irrigation

“…, aerogels, hydrogels, films, fabrics and sponges) is of particular interest. 46–67 Although atmospheric water is considered as a promising solution for the growing scarcity in agriculture, few sorption-based AWGs have been developed for the specific use in solar-powered irrigation. 7,33,34 Design of integrated AWG systems for energy-efficient, water-saving and self-sustaining agriculture is still beyond reach.…”