Pervaporative dehydration of industrial solvents using a zeolite NaA commercial membrane

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 degreesC. 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 degreesC. The separation factor for the THF-water separation was as high as 20000, 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, p*(w)-p(w)(p). From the regression of the experimental data, preliminary values of water permeability were obtained that varied in the range 5.5 x 10(-3) kg/(m(2)/ (h/mbar)) < K-W < 7.4 x 10(-3) kg/(m(2)/(h/mbar)) in the experimental range of operation temperatures. (C) 2003 Elsevier Science B.V. All rights reserved.