Designing a bioinspired synthetic tree by unidirectional freezing for simultaneous solar steam generation and salt collection

Abstract

Solar steam generation with thermal localization was recently proposed for highly efficient solar-thermal desalination. However, to achieve high steam productivity with long term stability remains a critical challenge due to salt accumulation at the evaporation surface. Here, we designed a T-shaped synthetic tree that could simultaneously achieve high steam productivity and salt collection with the structure characteristics of interfacial thermal evaporation, ambient energy harvesting and edge-preferential crystallizing. Under 1 sun, the synthetic tree exhibited a steady water evaporation rate of 2.03 kg m−2 hours−1 over 60 hours, achieving solar thermal efficiency of 75%. Salt was continuously rejected at the edge of the evaporator with a steady collection rate of 59.879 g m−2 hours−1, which did not affect water evaporation. This new design principle to simultaneously harvest water and salt provides a new avenue for solar energy utilization. (Figure presented.).