Polyurethane foam loaded MoS2 aerogel for efficient solar evaporation with excellent salt-rejection property

Abstract

To achieve salt-rejection and long-time operation of solar evaporators remains a challenge for seawater evaporation based on interfacial solar heating. In this work, a polyurethane foam loaded MoS2 aerogel (denoted as PU-MoS2 aerogel) was prepared using MoS2 as the photothermal material, polyvinyl alcohol (PVA) as the aerogel framework material and polyurethane (PU) foam as the support material. The as-prepared PU-MoS2 aerogel possessed characteristics such as wide light absorption, developed pore structure, strong hydrophilicity and water absorption, good thermal insulation and high mechanical strength, which makes it has high water evaporation rate of 1.22kg·m−2·h−1 under 1 sun illumination. It also exhibited an excellent salt-rejection property since the high concentrated brine at the surface of the PU-MoS2 aerogel could be refluxed back to the underneath unevaporated seawater through the hydrophilic PVA and developed pore structure of PU foam. As a result, the PU-MoS2 aerogel had high stability for long-time operation, the water evaporation rate kept unchanged even after 10 cycles of use. Finally, we demonstrated that inorganic salts and organic contaminants in condensed freshwater can be well reduced by the PU-MoS2 aerogel.