Bio-inspired 3D architectured aerogel evaporator for highly efficient solar seawater desalination

Solar interface evaporators for desalination have gained a growing research interest due to its potential for sustainable water production. However, an efficient balance in performance for heat management, water transport, and salt tolerance and rejection is rather difficult to achieve in actual applications. Inspired by the vascular bundles arranged in order in parenchyma cells of seagrass, this study reports the vertical arrangement of 3D aerogel formed by the hybridization of sodium alginate and reduced graphene oxide (denoted as SrGAE) to demonstrate a highly efficient solar interfacial evaporation for desalination. Due to the biomimetic 3D architecture with vertically arranged channels, SrGAE successfully achieves a shortened distance for water transmission and expanded channel for salt discharge in comparison to a traditional evaporator. Furthermore, SrGAE can absorb external energy through evaporative cooling and reduce the water-evaporation enthalpy, achieving an excellent solar-steam conversion efficiency. Such properties of SrGAE enable a continuous evaporation of 20 wt% brine for 8 h under one sun illumination, thus achieving an evaporation rate of 3.7 kg·m −2 ·h - ¹ and an outstanding solar-vapor conversion efficiency of 106 %. Inspired by seagrass structures, this study introduces a vertically arranged 3D aerogel (SrGAE) made from sodium alginate and reduced graphene oxide. The design reduces water transmission distance, enhances salt discharge, and absorbs external energy through evaporative cooling, lowering water-evaporation enthalpy. SrGAE achieves a solar-vapor conversion efficiency of 106 % and an evaporation rate of 3.7 kg m⁻² h⁻¹ under one sun illumination and 20 wt% brine. This biomimetic design offers a blueprint for developing high-efficiency solar interfacial evaporators for desalination. • Inspired by the seagrass, 3D architecture of the evaporator enables simultaneous fast water transport and salt rejection. • The evaporator has a wide absorption range and good thermal insulation. • The evaporator achieves an outstanding evaporation rate of 3.7 kg·m -2 ·h -1 at solar-vapor conversion efficiency of 106%.