A comparative study of the breakdown of cyclohexane- and toluene-based microemulsions by pervaporation technique

Two types of microemulsions, cyclohexane/water/n-butanol/sodium dodecylsulfate (SDS) and toluene/water/n-butanol/SDS, were prepared, and the study of their breakdown by pervaporation technique using 2% crosslinked (silicone resin) PDMS membrane was undertaken. The physico-chemical and rheological properties of these microemulsions were assessed. Results of the sorption of these microemulsions and their respective components by PDMS membrane revealed that the cyclohexane and the cyclohexane-rich microemulsion swelled better than the toluene and the toluene-rich microemulsion. Removal of the organic component led to microemulsion collapse. The optimal percent volumes of cyclohexane and toluene required to destabilize the organic-rich microemulsions were 18.5 and 17%, respectively. Total permeate flux and enrichment factor were examined as a function of the following parameters: temperature, time and crosslinking extent of the membrane. The conditions for optimal flux and enrichment factor were: temperature of 45 °C, time of 2 h and 2% crosslinked PDMS membrane. A closer pervaporation performance was observed for the two types of microemulsions.