Highly efficient solar seawater evaporation by aerogel with vertical channels and hierarchical pores structure based on high-absorbent alginate fibers

Utilizing interfacial evaporation under sunlight is an effective way for desalination. Researchers have developed various solar evaporators to replace traditional processes. However, crystalline salt deposition and low evaporation rates have hindered the application of solar evaporators, which remain critical challenges in the field. Inspired by vascular plants, a novel strategy using natural high-absorbent alginate fibers as the aerogel backbone and polypyrrole as the solar absorber was employed to prepare an eco-friendly solar evaporator in this study. The biomimetic evaporator with abundant hydrophilic groups, vertical channels, and hierarchical pores structure inside achieves a maximum evaporation efficiency of 4.27 kg m-2h- 1 under one solar intensity radiation, with an energy efficiency of more than 99 %. The nano polymer photo absorbents provide composite aerogels with excellent light absorption and mechanical properties, maintaining their shape and evaporation efficiency even after repeated use dozens of times. Its unique structures reduce water transport resistance radially to provide a fast water transport channel and efficiently desalinate, preventing salt from crystallizing on the evaporator surface. Obtaining a structurally controllable solar-driven evaporator in this way is expected to be used on a large scale for high-efficiency water purification, solving the freshwater resource crisis.