Robust superhydrophilic attapulgite-based aligned aerogels for highly efficient and stable solar steam generation in harsh environments

Abstract

The increasing demand for freshwater and the intensification of environment pollution have driven the exploration of high-performance photothermal conversion materials for solar-driven interfacial evaporation (SIE) to produce fresh water. However, the preparation of photothermal conversion materials with high mechanical strength, low cost and sustainability is still a challenge. Herein, an aligned attapulgite-based aerogel with high content of attapulgite (ATP) and high mechanical strength was prepared by chemically/physically cross-linking nano-fibrillated cellulose (NFC), polyvinyl alcohol (PVA) and glutaraldehyde (GA). The resulting ATP-based aerogels were characterized by SEM, N₂-adsorption/desorption, axial compression experiment, thermal conductivity test and UV-vis-NIR spectroscopy. The results show that the as-prepared ATP-based aerogels exhibit a three-dimensional macroporous structure, high mechanical strength, low thermal conductivity and excellent light absorption ability. As a solar steam generator, the desired aerogel not only possesses a high energy conversion efficiency of 87.6% in pure water, but also shows highly efficient and stable evaporation performance in harsh environments, such as high-concentration brine water, acid solution, alkali solution, and hot water. In addition, it also exhibits superiorities such as a flexible tunable structure and scalable preparation due to the combination of material selection and rational design. This work provides an insight for the rational design of photothermal conversion materials, showing potential applications in high brine water and harsh environment desalination.