Solar-driven artificial tree desalination with enhanced stability and performance via structural and materials optimization

Abstract

This study presents a novel solar-driven desalination artificial tree device designed to enhance sustainable freshwater production through a series of structural and material optimizations. A well-tuned draw solution is developed to improve system stability, enabling effective long-term operation with an evaporation layer featuring nanopores smaller than 100 nm. This enhancement allows for the use of a thinner anodized aluminum oxide membrane, reducing thermal resistance and facilitating efficient mass and heat transfer. The device structure is optimized into a compact, horizontal configuration, with a reduced air gap thickness to minimize vapor diffusion resistance and maximize sunlight absorption from multiple angles. As a result, the five-stage device achieves a steady-state water yield of 1.78 kg m^-2h^-1 under 1 kW m^-2 light intensity with a 3.5 wt% NaCl solution—a 17.88% improvement over the pre-optimization design. The device exhibits stable freshwater production over multiple cycles, with an ion rejection rate approaching 99.9% and salinity levels well below the WHO.