Long-Term Efficient Interfacial Solar Desalination Enabled by a Biomimetic 2D Water-Transport Structure Based on Silicone Nanofilaments

Abstract

Solar-driven interfacial evaporation (SIE) has drawn increasing attention for seawater desalination. Two-dimensional water-transport structures (2D-WTS) can enhance SIE performance by reducing heat loss of conventional evaporators but suffer from poor salt resistance due to insufficient water supply, which inhibits vapor escape and thus reduces evaporation rate. Inspired by the transpiration of plant leaves, we report the design of a 2D-WTS with controllable morphology by growing silicone nanofilaments on a polyethylene/polypropylene fabric. 2D-WTS has a hierarchical micro-/nanostructure for fast water supply like the multiscale vascular system of leaves. Consequently, the separated solar evaporator composed of 2D-WTS and polypyrrole/attapulgite@aluminium photothermal sheet achieves long-term efficient SIE, i.e., high evaporation rate (2.23 kg m–2 h–1, 3.5 wt % NaCl(aq), 1 sun), stable SIE of concentrated brine over 10 days (∼2.10 kg m–2 h–1, 10 wt % NaCl(aq), 7 h irradiation per day, 1 sun), and high practical evaporation rate of 7.36 kg m–2 during 7 h outdoor SIE under weak sunlight and low temperature (0.3–0.6 sun, 2–13 °C). This is because fast water transport in 2D-WTS forms a small salt deposition area close to the edge of the horizontal area of 2D-WTS during long-term SIE, which hardly affects the vapor escape