Dehydration of industrial ketonic effluents by pervaporation. Comparative behavior of ceramic and polymeric membranes

Pervaporation dehydration of an industrial ketonic waste mixture was studied. The performance of two membranes were investigated: (1) a polymeric membrane based on cellulose sulfate polyelectrolytes (Symplex membrane, GKSS) and (2) an inorganic microporous silica membrane (Pervap SMS, Sulzer Chemtech). The main components of the industrial feed mixture were acetone and water, initial water content C-H2O : 25 -30 wt%. For both membranes, the total flux and the water flux decreased as the feed water concentration decreased. The effect of pervaporation temperature in the 40degreesC to 70degreesC range was investigated. The compared results show that the feed can be efficiently dehydrated with the two membranes under study, although the dehydration process is more efficient using the polyelectrolyte, membrane since it provides a much higher water flux. The corresponding retentate could be incinerated without additional fuel in both cases. However the ceramic silica membrane yields an aqueous permeate with homogenous organic content and better environmental characteristics than the polyelectrolyte membrane. Apparent activation energies for water permeation through the polyelectrolyte and the silica membranes were calculated.