Novel Sponge-Based Carbonaceous Hydrogel for a Highly Efficient Interfacial Photothermal-Driven Atmospheric Water Generator

Abstract

A high-performance atmospheric water generator based on continuous adsorption−desorption of liquid hygroscopic agents was constructed by applying interfacial photothermal evaporation technology to the field of atmospheric water harvesting. A three-dimensional carboncontaining sponge hydrogel photothermal conversion material with a porous channel structure was designed, which was prepared from melamine foam (MF) and carbon black (CB) cross-linked by sodium alginate (SA). The results showed that the evaporation rate of CB/SA@ MF in pure water was 1.90 kg•m −2 •h −1 , and the photothermal conversion efficiency could reach 85.0%. The multistage pore structures and water transport channels in the A4 configuration device provided an excellent structural basis for material salt resistance and liquid hygroscopic agent regeneration. Using sponge-based CB/SA@MF hydrogel photothermal composites as the evaporation interface and liquid hygroscopic salts as the air−water trapping agent, an interfacial photothermaldriven atmospheric water generator successfully absorbed water at night and produced water during the day. Its water production could reach 2.84 kg•m −2 •d −1 . The cost of the atmospheric water generator was only $12, and the water quality obtained after 5 cycle tests met WHO/GB 5749-2022. This research was designed to collect fresh water from the air, bringing convenience to inland arid regions as well as remote and scattered areas with limited power resources.