Pervaporative dehydration of industrial solvents using a zeolite NaA commercial membrane

Abstract

Abstract This work reports an experimental study on the pervaporative dehydration of two industrial solvents using a commercial zeolite NaA-type ceramic membrane (SMART Chemical Company Ltd., UK). The mixtures studied are tetrahydrofuran (THF) with an initial water content of 7.9 wt.% and acetone with an initial water content of 3.25 wt.%. Batch experiments were carried out until final water content was lower than 0.1 wt.% in THF mixtures and lower than 0.2 wt.% in acetone mixtures. The influence of feed composition and feed temperature on the pervaporation fluxes and selectivities has been investigated. In the THF dehydration for a water concentration in the retentate of 7 wt.%, the water flux increased from 0.43 to 0.98 kg m−2 h−1 for a temperature increase from 45 to 55 °C. In the acetone dehydration for a water concentration in the retentate of 3 wt.%, the water fluxes increased from 0.13 to 0.314 kg m−2 h−1 for a temperature increase from 40 to 48 °C. The separation factor for the THF–water separation was as high as 20 000, although the separation factor was found to be dependent on the feed water concentration. The water flux through the ceramic membrane shows a linear dependency with the driving force, which is the partial equilibrium vapor pressure of water in the retentate minus the partial pressure in the permeate, pw*−pwp. From the regression of the experimental data, preliminary values of water permeability were obtained that varied in the range 5.5×10−3 kg/(m2/(h/mbar))≤Kw≤7.4×10−3 kg/(m2/(h/mbar)) in the experimental range of operation temperatures.