Enhanced Directional Seawater Desalination Using a Structure-Guided Wood Aerogel

TLDR

Solar‑powered seawater desalination promises to alleviate freshwater scarcity, yet its practical viability is hindered by limited air‑water interfaces, significant heat loss, and ecological concerns. The authors designed a novel wood‑derived indirect‑contact (hanging) photothermal evaporation system. The system employs a wood‑based hanging structure that facilitates indirect‑contact photothermal evaporation. The wood‑derived hanging system achieved a record evaporation rate of 1.351 kg m⁻² h⁻¹ and 90.89 % efficiency under one sun, with simulations revealing that oriented seawater collection, photothermal thermogenesis, and natural convection synergistically drive the process, and the design offers superior mechanical strength, repeatability, ecological security, and thermal stability.

Abstract

Seawater desalination via solar energy has potential to alleviate freshwater scarcity. However, problems including insufficient air-water interface, large heat loss, and potential ecological impact have restricted its practical viability. Here, a novel wood-derived indirect-contact (hanging) photothermal evaporation system was designed. An evaporation rate of 1.351 kg·m-2·h-1 with efficiency up to 90.89% under one sun illumination (1 kW·m-2) was achieved, which is the highest record to the best of our knowledge. More importantly, a series of simulations and numerical modeling were carried out to analyze the main factors affecting seawater collection and evaporation, and the synergetic mechanisms of oriented seawater collection, photothermal thermogenesis, and natural convection were elucidated. Taken together, this study provides a new wood-derived hanging seawater desalination system with superior mechanical strength, good repeatability, great ecological security, and excellent thermal stability. The corresponding mechanisms of the whole process are shown, and the seawater evaporation efficiency approaching the real demand is maximized.