A composite hollow fiber membrane-based pervaporation process for separation of VOCs from aqueous surfactant solutions

The separation and recovery of VOCs from surfactant-containing aqueous solutions by a composite hollow fiber membrane-based pervaporation process has been studied. The process employed hydrophobic microporous polypropylene hollow fibers having a thin plasma polymerized silicone (PDMS) coating on the outside diameter, trichloroethylene (TCE) as the model contaminant and sodium dodecyl sulfate (SDS) as the surfactant. The feed solution was passed through the fiber bore; the shell side had vacuum. The process operating parameters, e.g., feed flow rate, TCE and SDS concentrations, were varied over a wide range to investigate their effect on the process performance. Depending on the concentration of the surfactant, separation of VOCs can be achieved via two different conditions, namely, wetted pore and non-wetted pore. The resistances-in-series concept successfully applied earlier to the TCE-water system has been extended to the TCE-SDS-water system for both wetted pore and non-wetted pore conditions. Results will be provided also for a more complex feed solution containing alcohols and the hydrophilic polymer, xanthan gum. (C) 1999 Elsevier Science B.V. All rights reserved.