Organic solvent reverse osmosis separations of hydrocarbon-alcohol mixtures using matrimid membranes

The organic solvent reverse osmosis (OSRO) separation of alcohol-hydrocarbon mixtures with Matrimid membranes is studied via experiment as well as modelling with dry glass reference perturbation theory (DGRPT). It is shown that the separation of these mixtures is highly non-ideal, with strong maxima of the separation factors as a function of feed composition. The DGRPT model was fit to pure vapor sorption data, while the Fickian diffusivities were fit from pure liquid permeation data. From this pure component parameterization, the model successfully predicted the highly non-ideal separation behavior observed for mixtures of alcohols and hydrocarbons. Successful application of the model was crucial in the interpretation of the experimental data, conclusively showing that the non-ideal behavior observed in the separations was a result of thermodynamic phenomena.