Flexible and robust nanofiber sponge with superior capacity to transport water for efficient and sustained solar-driven interfacial evaporation

Abstract

Solar-driven interfacial evaporation is an emerging route for desalination and wastewater treatment with great potential to alleviate freshwater shortages. However, the current solar-driven interfacial evaporation systems generally suffer from complex design, poor customization and salt accumulation issues. Design and preparation of solar-driven interfacial evaporation systems with excellent comprehensive performance and capable of being mass-produced remains a great challenge. Herein, we demonstrate a novel electrospun nanofiber sponge for efficient and sustained solar-driven interfacial evaporation. The nanofibrous structure of its surface can promote the absorption of light, and its interconnected pore structure is conducive to the diffusion of water vapor, thereby improving the evaporation effect. Under 1 sun irradiation (1 kW·m−2), the nanofiber sponge interfacial evaporation system showed an outstanding water evaporation rate (1.57 kg·m−2·h−1) with 95.6 % evaporation efficiency. The hierarchical porous structure, super-hydrophilic properties and integrated design of evaporation and mass transfer make it have superior water transport capacity and excellent salt self-discharge performance. Simultaneously, the excellent strength, flexibility, and processability of the nanofiber sponge can realize the customized fabrication of solar interfacial evaporation systems. This work is expected to advance the development of solar-driven interfacial evaporation systems toward compact, independent and portable.