Solar-Powered Guar Gum/Nanocellulose Aerogel for Atmospheric Water Harvesting

Freshwater scarcity poses a significant challenge to global sustainable development, while existing atmospheric water harvesting (AWH) materials are often limited by complex fabrication, high cost, salt leakage, and slow sorption–desorption kinetics. We developed a multifunctional GG-CNF/E-LiCl/CB biopolymer aerogel, where guar gum (GG) and nanocellulose (CNF) were used as polymer matrices and cross-linked with methyltrimethoxysilane (MTMS) to form a three-dimensional network. This structure facilitated the uniform dispersion of ethanolamine-modified lithium chloride (E-LiCl), enabling efficient moisture capture and transport. Alkynediol (TMDD) prevented carbon black (CB) agglomeration via physical adsorption, thereby enhancing the photothermal conversion efficiency. The aerogel exhibited remarkable moisture sorption across a broad humidity range (30%–90% RH), with a water uptake of 2.05 g g–1 at 70% RH. Under simulated solar irradiation (0.5–1.5 sun), >73% of the adsorbed water was released within 100 min. Its dehumidification performance outperformed conventional desiccants (4A molecular sieve and silica gel), reducing humidity from 90% to 19.4% within 100 min. The biopolymer aerogel combines simple fabrication with environmental sustainability, highlighting its promise for sustainable water vapor utilization.