Sulfonated graphene oxide based membranes with enhanced water transport capacity for isopropanol pervaporation dehydration

By utilizing the synergistic effect of polyelectrolyte (PEL) and sulfonated graphene oxide (SGO), novel composite membranes were prepared to achieve ultrafast transport of water molecules in isopropanol pervaporation dehydration. As confirmed by FTIR, Raman, XPS and XRD measurements, the sulfonation modification resulted in defects and uneven interlayer structure within SGO membrane (SGOM), which could enlarge the free volume for low-resistance water channels. The microstructure changes of composite membranes were observed via FESEM. The measured pervaporation behavior of pure components indicates that the transport capacity of SGOMs has been enhanced compared with graphene oxide membranes. After coated with an ultrathin PEL layer, the synergistic effect of highly enhanced water adsorption from the PEL layer and ultrafast permeation channels from SGOM facilitates the rapid and selective transport of water molecules through the membrane, which ensures excellent isopropanol dehydration performances. Both the flux and separation selectivity increase with temperature. At 70 degrees C, the flux can reach up to 3.67 kg m(-2) h(-1) with 99.90 wt% water content in permeate. The prepared membrane also possesses enhanced mechanical strength with firm interfacial adhesion. All the results evidence that SGO-based membranes possess outstanding advantages in isopmpanol dehydration.