Biomimetic TPMS Structure-Based Entangled Hydrogel for Efficient Solar-Driven Atmospheric Water Harvesting.

Abstract

Atmospheric water harvesting (AWH) is emerging as a sustainable and decentralized strategy for producing freshwater. However, achieving rapid AWH remains challenging due to the slow sorption kinetics, especially in the case of thick hygroscopic hydrogels. Here, a TPMS structure-based entangled hydrogel mesh (TSEHs) is proposed, featuring a hierarchical porous structure that facilitates a high mass transfer coefficient and a significant air-hygroscopic site interface. The TPMS-based hierarchical structure endows the TSEHs with rapid sorption-desorption kinetics. As a result, in comparison to conventional dense hydrogels (CDHs), TSEHs achieve a remarkable reduction in sorption time by 385%. When the thickness of TSEHs increases from 2 to 12 mm, only a slight decrease in equilibrium sorption time is observed, while CDHs exhibit an exponential increase in equilibrium sorption. Furthermore, the rapid water uptake of ultra-thick TSEHs is demonstrated at 50 mm, which, to the best of the knowledge, represents the largest recorded thickness for hygroscopic gels. Additionally, a continuous solar-driven TSEH-based water production prototype is developed, achieving a high water collection rate of 4.89 kg m^-2 under 1 sun and showcasing its significant practical potential.