Emulsified oil is a component of wastewater generated by petroleum refineries, food processing facilities, metalworking operations, oil extraction and many other industries. Removing the oil phase is often necessary to meet environmental regulations. Membrane filtration can remove drops smaller than 10 microns (a challenging task where other high throughput technologies fail!) but membrane fouling by oil hinders a broader acceptance of this approach. Current studies in our research group focus on understanding mechanisms of membrane fouling by emulsified oil and developing methods of mitigating this problem.
We use modeling of oil-membrane interactions, oil adhesion studies, and bench-scale membrane separation tests to gain a quantitative understanding of oil drop behavior on various membrane surfaces. Our experimental methods include surface and interfacial tension measurements, light diffraction for drop size analysis, confocal microscopy, oil adhesion measurements using quartz crystal microbalance with dissipation (QCM-D), and Direct Observation Through the Membrane (DOTM) studies. The DOTM work is a collaboration with Dr. Jia Wei Chew from the Singapore Membrane Technology Center (SMTC) and is supported by the US NSF funded project “PIRE: Water and Global Commerce: Technologies to enable environmental sustainability in global markets” (grant OISE-1243433).