Hypergravity field induced self-assembly of 2D MXene in polyvinyl alcohol membrane matrix and its improvement of alcohol/water pervaporation

Hydrophilic nanomaterials were always used to improve the pervaporation (PV) performance of polyvinyl alcohol (PVA) membrane in the process of ethanol dehydration. In this work, the PVA/MXene composite membrane with high water flux and separation factor was fabricated with spin coating method. Induced by the hypergravity force, the MXene nanosheets were segregated and stacked layer-by-layer between the interface of the PVA/MXene layer and the support. The self-assembly 2D MXene in the PVA not only improved the binding force between the separation layer and the support but also enhanced the PV performance. The water flux and separation factor of the PVA/SSA/MXene composite membrane reached 1.22 kg & BULL;m(-2)& BULL;h(-1) and 1577, respectively. Both were higher than those of most reported PVA membranes. Nano indentation and scratch tests also revealed that due to the high modulus and hardness of the PVA/SSA/MXene composite membrane, 0.2822 and 0.019 GPa, strong binding force was existed between the separation layer and the support. Partly based on this reason, the structure of the PVA/SSA/MXene composite membrane remained stable during 300 hours of the PV test. It is believed that the prepared PVA/SSA/MXene composite membrane has a broad application prospect in the PV process for ethanol dehydration.