Ti3C2/PVDF membrane for efficient seawater desalination based on interfacial solar heating

Abstract

The photothermal material of Ti3C2 was synthesized by etching Ti3AlC2 with hydrofluoric acid. The as-prepared Ti3C2 was deposited on a polyvinylidene fluoride (PVDF) membrane via vacuum filtration to form a Ti3C2/PVDF membrane, which was used for seawater desalination in the next step based on interfacial solar heating. The water evaporation rate of the Ti3C2/PVDF membrane could be enhanced to 0.98 kg/m2·h under 2 sun irradiance, which was 2.8 times and 5.4 times higher than that of pure water (0.35 kg/m2·h) and PVDF (0.18 kg/m2·h) respectively. The temperature difference between the two air–water interfaces with and without the Ti3C2/PVDF membrane was as high as 11.8 oC, confirming the interfacial heating behavior. The water evaporation rate under 2 sun irradiance kept mostly in the range of 0.96–0.86 kg/m2·h over 30 days under continuous operation, indicating the high stability of the Ti3C2/PVDF membrane. Finally, it was demonstrated that the typical water-quality indexes of the condensed fresh water were below the limit values of the Standards for Drinking Water Quality in China, WHO, and US EPA.