Graphene membranes may lead to enhanced natural gas production, less CO2 pollution
12 Oct 2012
Engineering faculty and students at the University of Colorado Boulder have produced the first experimental results showing that atomically thin graphene membranes with tiny pores can effectively and efficiently separate gas molecules through size-selective sieving.
The findings are a significant step toward the realisation of more energy-efficient membranes for natural gas production and for reducing carbon dioxide emissions from power plant exhaust pipes.
Mechanical engineering professors Scott Bunch and John Pellegrino co-authored a paper in Nature Nanotechnology with graduate students Steven Koenig and Luda Wang detailing the experiments. The paper was published Oct. 7 in the journal's online edition.
The research team introduced nanoscale pores into graphene sheets through ultraviolet light-induced oxidative ''etching,'' and then measured the permeability of various gases across the porous graphene membranes.
Experiments were done with a range of gases including hydrogen, carbon dioxide, argon, nitrogen, methane and sulphur hexaflouride -- which range in size from 0.29 to 0.49 nanometers -- to demonstrate the potential for separation based on molecular size. One nanometer is one billionth of a meter.
''These atomically thin, porous graphene membranes represent a new class of ideal molecular sieves, where gas transport occurs through pores which have a thickness and diameter on the atomic scale,'' said Bunch.
