Like oil and water

PITTSBURGH (June 22, 2020) — In the petroleum industry, the ability to separate oil and water is critical. Oily wastewater from drilling and processing crude oil is the biggest waste stream in the oil and gas industry, which produces three times as much waste as it does product.

Lei Li, associate professor of chemical and petroleum engineering at the University of Pittsburgh’s Swanson School of Engineering, has received $110,000 from the American Chemical Society (ACS) Petroleum Research Fund (PRF) for his work developing 3D-printed membranes that will aid in oil-water separation. The development could help convert the oily wastewater into purified, usable water.

“The ideal case for a membrane that serves this purpose is a material that is oleophobic and hydrophilic–in other words, one that hates oil but loves water,” said Li. “What’s new about this work is its focus on surface and in-pore topography: The texture of the surface of the material and even the texture inside of the pores of the material have a profound effect on the membrane’s effectiveness.”

Current fluorinated hydrophilic and oleophobic membranes have been shown to be effective in the short-term but lose their properties in the long-term. Li’s method will instead rely on water as a thermodynamically stable material and will engineer the surface topography inside the membrane’s pores so that the water and oil remain separated.

“Previously, such features were fabricated by nanolithography methods, which are slow and expensive. In this project, we propose to take advantage of two-photon polymerization 3D-printing technique,” explained Li. “Compared to traditional manufacturing technology, this provides a reasonably fast, single-step process to fabricate complicated structures.”

Additionally, the high resolution that two-photon polymerization 3D-printing enables will allow the researchers to make the membrane’s pore size down to a few hundred nanometers, which is critical in separating oil-water emulsions.

The grant will last for two years, beginning Sept. 1, 2020.

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