Wood-inspired biomimetic vascular evaporator for highly efficient and stable solar steam generation in harsh environments

Abstract

Solar-driven interfacial evaporation has great potential in freshwater harvesting, but it remains a huge challenge to maintain the structural stability of solar evaporator in complex and harsh environments while ensuring the water evaporation capacity. Herein, inspired by the mechanical stability and water transportation capability of vascular system in natural wood, a biomimetic vascular evaporator (BVE) was prepared by ice template induced self-assembly method for high-efficiency solar energy-driven seawater desalination and wastewater purification in harsh environments. Due to the ice crystals grow vertically and sublimate, the gel was squeezed to form a structure like vascular bundles with a uniform three-dimensional network structure and parallel vascular pores. The experimental results show that the vascular structure of BVE provides effective structural stability that 1000 times of repeated compression at 80% deformation without being destroyed. Meanwhile, integrating rapid water transportation capability, thermal positioning effect, and the reduced vaporization enthalpy endow high evaporation capacity (2.37 kg m−2 h−1, 93.11% pure water efficiency) under 1 sun irradiation. In particular, the above performance of BVE allows it to maintain a high and stable freshwater production capacity in various harsh environments, such as acid and alkali solutions, organic dyes, heavy metal wastewater, and wet soil. This work provides new insights into the rational design of the bionic photothermal evaporator, and demonstrates its potential application in long-term effective wastewater purification in harsh environments.