Flexible layered double hydroxides array composite membrane for efficient pervaporation desalination

Abstract

Pervaporation has been considered a promising technique in seawater desalination. Developing new and efficient pervaporation membrane material remains the main challenge. In this study, the layered double hydroxides (LDH) nanosheet array composite membranes were prepared on a commercial polyacrylonitrile ultrafiltration membrane through the hydrothermal method. The structure and morphology of the LDH array was regulated by the hydrolysis of the substrate and the hydrothermal conditions. The obtained LDH composite membrane had a good pervaporation desalination performance due to its unique water molecular transport channel and high hydrophilicity. When the salt concentration in the feed solution increased from 3 to 10 wt%, the rejection of the composite membrane could maintain at 99.8 %. The real seawater was also used to evaluate the membrane. The results indicated the LDH composite membrane had a good desalination performance in a relatively wide range. Moreover, the LDH composite membrane exhibited excellent flexibility and stability. We anticipated that the membrane may have great potential in pervaporation desalination.