Extraction of Oil from an Aqueous Emulsion by Coupling Thermal Swing with a Capillary Pump

Separation of oil from water is an area of increasing interest because of the ever-increasing emphasis on reducing discharge of oily wastewater streams and for managing accidental oil spills. While several methods to separate oil from water are available, the current methods often require elaborate processing steps and/or have low extraction rates. Here, we report two simple and potentially inexpensive methods of separating oil from aqueous emulsions. The first method employs hydrophobized glass wool in a pressure-driven capillary pump, while the second method employs novel zeolite pellets the exterior surface of which is hydrophobic. These pellets selectively absorb oil from an aqueous emulsion, which can subsequently be recovered using thermal swing with hot fluid at a temperature far below the boiling point of the oil. Separation of oil with a very high yield (ca. 97%) appears possible using a combination of the two methods.