Preparation and applying the membranes with carbon black to pervaporation of toluene from the diluted aqueous solutions

Abstract

The application of pervaporation (PV) to the removal of volatile organic (VOC) from the aqueous solutions has become very interesting in the last few years. It is caused by the increasing level of the compounds such as petrochemical solvents (benzene, toluene, and xylenes) or chlorinated solvents (trichloroethylene or tetrachloroethylene) in the natural environment. The aim of this work is to apply the membranes with carbon black as a filler to pervaporation (PV) of toluene from the diluted aqueous solution. In the research polydimethylsiloxane (PDMS) composite membranes, PDMS and PEBA (polyether-block-polyamide) membranes filled with carbon black were used. The membranes were prepared in a laboratory scale especially for this purpose. Both PEBA and PDMS membranes show excellent properties to separate toluene from the water, however, toluene solubility in the PDMS membrane was better, it could be observed that the removal of this compound from the feed was better when this membrane was used. In consequence the process selectivity increases and better concentration of toluene on the permeate side can be obtained. The influence of the membrane filler on the total flux, toluene flux and process selectivity was also determined. In some cases total flux as well as toluene flux decrease for the membranes with the filler comparing to those without the filler.