(421c) Complex Aromatic Hydrocarbon Mixture Osro Separation Using Defect-Engineered Torlon® Hollow Fiber Membranes

The fractionation of complex liquid hydrocarbon mixtures is an important emerging area of membrane science. Polymeric asymmetric hollow fiber membranes can enable this concept, especially if size and number of defects in the membrane skin layer can be precisely engineered. Here, we fabricated various “defect-engineered” hollow fiber membranes by modifying the composition of the volatile solvents of the polymeric solution as well as spinning parameters to improve the organic solvent reverse osmosis (OSRO) separation performance of complex aromatic hydrocarbon mixtures. The quality of the membranes was probed using both gas and liquid permeation tests, which provided the data for a useful fundamental analysis that estimates the pore size and surface porosity of the asymmetric hollow fiber membranes. That information, combined with organic solvent permeation data, provides an engineering platform to estimate the relative permeation rates of organic molecules within a complex mixture. For instance, we will assess the ability of combined transport modality permeation models (i.e., sorption-diffusion + hydraulic flow) to predict the membrane’s ability to fractionate complex mixtures of aromatic hydrocarbons. Useful approximations and apparent deficiencies in this transport “framework” will be discussed. Although we have employed hydrocarbon mixture fractionation to illustrate our approach, we believe the membrane-based fractionation concept to be highly relevant across a range of existing and emerging separation challenges, including biorefinery separations and downstream separations in futuristic “e-refineries”