用于海水淡化的水母状双层太阳能蒸发器：一种将热量与质量传递相结合，实现供水与蒸发最优匹配的技术方案

Abstract

Bioinspired jellyfish-like design with Cu 2 O@urushiol cotton fabric • Coupled heat and mass transfer model optimizes water supply-evaporation matching. • High evaporation rate 2.3 kg·m −2 ·h −1 , 4.9× pure water • Outstanding salt rejection: 22 kg·m −2 over 10 h from 7 wt% brine • Multifunctional: antibacterial, photocatalytic, and water safe for irrigation Solar-driven evaporation offers a promising route to address freshwater scarcity. However, most existing planar thin-film evaporators focus primarily on photothermal materials, while the rational design of the water-delivery layer and the underlying supply-evaporation matching mechanism remain underexplored. Herein, we report a jellyfish-like bilayer solar evaporator comprising a Cu 2 O@urushiol-modified cotton fabric (Cu 2 O@Ur/CF) as the photothermal layer and a cotton fabric with four extended strips as the water-delivery layer. By systematically optimizing strip width and number, we identify an optimal configuration (7.5 mm, four strips) that achieves an evaporation rate of 2.3 kg·m −2 ·h −1 under 1.0 sun irradiation – approximately 4.9 times that of pure water. Notably, we develop a coupled heat and mass transfer model that decomposes the total evaporation into baseline evaporation from the water surface beneath the photothermal layer and strip-supplied evaporation from water transported through the cotton strips. The model reveals that the optimal configuration balances capillary-driven water supply and thermally driven baseline evaporation, yielding the highest photothermal layer temperature (82.4 °C) and thus the maximum evaporation rate. This coupled model provides a quantitative framework for optimizing water supply-evaporation matching in two-dimensional solar evaporation systems. In contrast, excessive strips (eight or double-layer eight) lead to surface cooling and reduced evaporation. The evaporator also exhibits outstanding stability, salt rejection (22 kg·m −2 over 10 h from 7 wt% brine), and