POSS-graphene oxide nanocomposite membranes for ethanol permselective pervaporation

Abstract

Pervaporation has shown great promise in recovering alcohol from fermentation broth. However, the separation performance determined by membrane material and structure should be further improved. In this study, polyhedral oligomeric silsesquioxane (POSS) nanocage was used as nanofillers to provide preferential pathways for ethanol molecules in polydimethylsiloxane (PDMS) membrane. To improve dispersion of POSS nanocages in PDMS matrix, the POSS were anchored on the graphene oxide (GO) nanosheets. At the meantime, the aggregation of GO nanosheets could also be prevented as the GO surface turned to be hydrophobic by the modification of POSS, and the nanoporous POSS cage could reduce interface defects between GO nanosheets and PDMS matrix. The obtained POSS-GO/PDMS nanocomposite membranes exhibited excellent separation performance for ethanol permselectivity. The flux could reach 1346.9 g m −2 h −1 with a separation factor of 11.2 when recovery of ethanol from 5 wt% ethanol/water mixture. In addition, the separation performance of the POSS-GO/PDMS membrane could maintain stability in 120 h. Therefore, the POSS modified GO nanosheets shown great potential in the fabrication of ethanol permselective pervaporation membranes. • POSS-GO nanocomposites were fabricated and incorporated into the PDMS matrix for preparation of pervaporation membranes. • The nanoplates can be well dispersed in PDMS as the hydrophobic POSS has been uniformed anchored to the GO nanosheets. • The obtained POSS-GO/PDMS membranes exhibited excellent pervaporation performance for ethanol permselectivity.