(421g) Multicomponent Liquid Hydrocarbon Transport in Polymeric Membranes

The separation of multicomponent, complex liquid mixtures, which are mixtures without a clear singular solvent, is an important, emerging area of membrane science. Transport models for polymeric materials have typically been applied to systems with three or fewer species; however, many critically important separations challenges involve complex mixtures containing dozens if not thousands of compounds. Here, we experimentally examine the ability of Maxwell-Stefan models to accurately predict complex mixture permeation in polymeric membranes based only on single component sorption and diffusion data. We specifically investigate the separation of a complex mixture of hydrocarbons covering a range of classes such as alkanes, cycloalkanes, alkyl aromatics, and polyaromatics. We observe strong sorption-based selectivity for aromatic compounds while diffusion-based selectivity dominates for aliphatic molecules. We utilize these experiments to test simplifying hypotheses regarding the estimation of sorption and diffusion coefficients of any arbitrary hydrocarbon in our polymer material. These simplifying hypotheses potential enable extension of our predictive capabilities to any N-component mixture of hydrocarbons, of which there are many industrially-relevant streams.