The breaking down of the 2-butanone/water/n-butanol/sodium dodecylsulfate microemulsion system by pervaporation technique: Effect of the stirrer rate

Abstract

The principle that stipulates the removal of a certain quantity of one of the microemulsion components leads to destabilize and break down a microemulsion. This work investigated the breaking down of two microemulsions by pervaporation technique: 2-butanone-rich and water-rich microemulsions. Poly(dimethylsiloxane) was used as a hydrophobic membrane for extracting 2-butanone from the oil-rich microemulsion system and poly(vinylalcohol) was used as a hydrophilic membrane for the removal of water from water-rich microemulsion. The pervaporation parameters, the total flux rate and the enrichment factor, were examined as a function of stirrer rate, time and temperature. During these operations a turbidity was observed in the feed, indicating that the microemulsion was broken down. It was observed that more marked breaking points of these microemulsions were obtained at the lower stirrer rates. At 60 °C, 2 h was sufficient for breaking down the microemulsions and extracting 9.0 ± 0.2 g (∼ 13 wt.%) of 2-butanone and 8.5 ± 0.2 g (∼ 16 wt.%) of water from the feed through the PDMS and PVA membranes respectively. The Arrhenius plot gives an activation energy of 2.49 ± 0.02 kcal mol- 1 and 2.82 ± 0.02 kcal mol- 1 for the 2-butanone and water-rich microemulsions respectively. © 2010 Elsevier B.V. All rights reserved.