Alkali treatment combined with surface carbonized wood for high-efficiency solar interfacial evaporation

Abstract

With the shortage of fresh water, one of the most promising strategies to solve this problem is solar interfacial evaporation. Due to the porous structure, low heat conduction, high hydrophilicity and renewability, we develop a wood-based solar generator by a facile method of alkali treatment and surface carbonization (ASC-wood). Surface carbonization could endow wood generators with a high sunlight absorbency and alkali treatment could improve the water delivery capacity. For further reduce heat conduction loss, an insulation-layer system was proposed in this work. Benefiting from these advantages, the ASC-wood generator can reach an evaporation rate of 1.21 kg m−2 h−1 and an evaporation efficiency of 81.3% under 1 sun irradiation. In addition, the ASC-wood generator shows an outstanding cycling performance and structural stability, which is favorable for outdoor applications. This work provides a simple method to manufacture a scalable, cost-effective, high-efficiency and high-strength solar steam generator. Also, the effect of water temperature on solar evaporation performance was studied, and results show that the pure evaporation efficiency will first increase and then decrease with the increase of water temperature from 20 ℃ to 40 ℃, indicating a way for improving the evaporation efficiency by matching the sensible heat as well as the latent heat.