Electrospun reduced graphene oxide/polyacrylonitrile membrane for high-performance solar evaporation

Abstract Solar-driven water evaporation is a method to make seawater sustainable by producing lower levels of greenhouse gases at present. Herein, we prepared an efficient, flexible and lightweight reduced graphene oxide (rGO)/ polyacrylonitrile (PAN) composite membrane by a simple electrospinning technology for photothermal desalination. After blending with rGO, the electrospun membrane exhibited a strong light absorption property in a wide spectral pectrum and can absorb more than 80% of the light. More importantly, the prepared rGO/PAN membrane presented advantages of good heat localization and high evaporation efficiency. When placed on a thermal barrier made by polystyrene foam, it converts 89.4% of the light into heat, allowing 1.46 kg m−2 of seawater to evaporate in an hour under one sun. Meanwhile, the rGO/PAN membrane was used as a steam generator to obtain the pure water with low ion concentration (Na+: 0.61 mg L−1, Mg2+: 0.67 mg L−1, K+: 1.71 mg L−1, and Ca2+: 0.48 mg L−1) from high salinity simulating seawater. Based on the results, the rGO/PAN membrane provides a new avenue for large-scale photothermal application in the field of seawater desalination.