The separation of olefin/paraffin (e.g., ethylene/ethane and propylene/propane) mixture is one of the most important processes in petrochemical industry because olefin is the valuable resource of modern chemistry and industry. For olefin/paraffin separation, many conventional separation techniques, such as distillation, have been conducted in harsh conditions (e.g., cryogenic). However, such separation techniques need high energy consumption because olefin/paraffin molecules have very similar molecular size and boiling point. Not only high operational cost but also large equipment capital and massive footprint hinder further cost reduction of olefin/paraffin separation. Membrane process has been considered as an alternative method to achieve energy-efficient olefin/paraffin separation. There are efforts to enhance the separation performance, such as change of fractional free volume of polymers, polymer packing, rigidity and segmental motion. However, based on solution-diffusion mechanism, it is hard to design proper membrane materials to separate olefin/paraffin efficiently. Here, we prepared graphene oxide (GO) thin film composite (TFC) membranes for olefin/paraffin separation. GO has oxygen-functional groups such as hydroxyl and epoxy groups on graphene surface. By stacking multiple layers of GO on polymeric substrates, GO membranes have slit-like gas permeable and selective channels. Here we report intrinsic separation properties of olefin/paraffin through GO membranes. Similar to carbon molecular sieve membranes, GO membranes showed an ability to separate olefin/paraffin molecules to some extent. To improve the separation properties, GO membranes could be modified by various approaches. Several additives were induced to enhance the separation performance and the materials and structure of TFC membranes were adjusted.

Olefin/paraffin separation properties of graphene oxide membranes

253rd National Meeting (2017)

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