Separation by pervaporation of methanol from tertiary amyl methyl ether using a polymeric membrane

Abstract

In this study, the sorption and pervaporation characteristics of the commercial PERVAP2256® membrane with methanol and tert-amyt methyl ether (TAME) mixtures were investigated. The feed concentration and the feed temperature were varied and quantities such as the degree of swelling, flux and selectivities were measured. The main objective of this study was to investigate the selective removal of methanol from mixtures of methanol and TAME (with an azeotropic point) by means of pervaporation. The experiments were conducted over the entire methanol concentration range at different temperatures ranging from 25 °C to 45 °C. The membrane was found to be highly methanol selective, with the permeate selectivity varying between 5 and 53, and fluxes as high as 12 kg m -2h-1. It was shown that methanol preferentially absorbed in the membrane and preferentially permeated through the membrane. Methanol can thus be successfully separated by the separation process of pervaporation from mixtures of methanol and TAME that include an azeotropic point. The permeation of the components through the membrane was modeled, based on the solution-diffusion model. The Flory-Huggins theory was used to describe the sorption step while Fick's first law of diffusion was used to describe the transport step. The predicted values showed good agreement with the experimental measurements in specific regions.