Aldehyde functionalized graphene oxide frameworks as robust membrane materials for pervaporative alcohol dehydration

- Three aldehyde functionalized GOF membranes have been molecularly designed.
- The resultant GOF membranes displayed adjustable microstructures.
- GOF membranes exhibited greatly improved alcohol dehydration performance.
- Excellent long term stability was found for the GOF membranes within 160-200 h.

To glue the graphene oxide (GO) nanosheets more firmly and to fabricate more stable GO membranes for long-term applications, three types of graphene oxide framework (GOF) membranes have been molecularly constructed via the aldehyde-functionalization of GO and a pressure assisted ultrafiltration method. The resultant GOF membranes not only possess GO/aldehyde covalent bonds but also display adjustable microstructural properties, confirmed by FTIR, XPS, XRD and positron annihilation spectroscopy (PAS). All aldehyde modified GOF membranes exhibited much improved separation performance for ethanol dehydration via pervaporation, as compared with the pristine GO membrane. The GOF membranes were also tested for the dehydration of ethanol, isopropanol, and n-butanol at different feed temperatures. Excellent separation performance at 60 °C for n-butanol dehydration was obtained with a high flux of 2593 g m−2 h−1 and the water concentration in permeate of 99.7 wt%. Importantly, the pervaporation stability of GOF membranes at a relatively high temperature was investigated for the first time. The membranes performed well for the dehydration of alcohols at 60 °C within a long period of 160-200 h.

Graphene oxide framework (GOF) membranes functionalized by three different aldehydes show adjustable microstructures, improved separation performance and good stability.201