Sugarcane inspired polydopamine @ attapulgite-based aerogels with vertical pore structure for solar-driven steam generation

Abstract

Desalination using solar-driven photothermal evaporators (SPEs) is of great significance for solving mankind's current shortage of fresh water. Herein, inspired by the vascular bundles for the directed and rapid transport of water and organic pollution such as inorganic salts in the vascular system of sugarcane, a polydopamine (PDA) @ attapulgite (ATP) based biomimetic aerogel (named as PAS aerogels) was prepared for efficient desalination. In PAS aerogels, the ATP gives the aerogel excellent mechanical properties, whereas the PDA gives the aerogel excellent light absorption properties. In the wet state, PAS aerogels have low thermal conductivity (0.24 W ∙ m−1∙ K−1) and low apparent density (0.13 g ∙ cm−3). Indicating that the photothermal evaporation rate of PAS-1.5 aerogel is 1.71 kg ∙ m−2∙ h−1 in pure water under 1 sun irradiation. Meanwhile, it can maintain excellent evaporation performance even in high salt solution with 20% concentration (about 1.50 kg ∙ m−2∙ h−1). Owing to the vertical pore structure of the aerogel, which is similar to that of sugarcane transport tissues, the aerogel has both an adequate supply of water and excellent salt tolerance. Furthermore, outdoor experiment of Yellow Sea water evaporation demonstrates its feasibility in the actual production of desalination.