During an oil-spill catastrophe, it is important to separate oil and water accurately on a massive scale, as quickly as possible. A POSTECH research team recently developed a technology that separates a solution of water and oil continually, quickly, and accurately. This technology can effectively prevent the spread of marine oil pollution and enable safe disposure of industrial oil wastes.

Jointly researched with a research team from Chungnam National University, Professor Lim Geun-bae (ME) and Hong Seong-kyung (ME, Ph.D. Integrated) created a hydrophilic oil-impermeable cellulose-based nanofiber membrane capable of fast, massive separation.

Prior to now, oil-spill accidents were treated with oil fences or dispersants, which causes the oil particles to sink underwater. However, both methods are problematic. Oil fences are affected heavily by the currents, waves, and wind, while dispersants can also cause pollution. On the other hand, industrial oil wastes are hardly separated into oil and water, making it difficult to discard safely.

The researchers fabricated a cellulose nanofiber membrane with a porous structure underwater. The membrane, with its porous structure, is capable of absorbing liquid and responding quickly. The membrane showed successful filtration abilities under gravity, but when it was given 30kPa of excessive pressure, the membrane separated 2,000 liters of a water-oil solution within a minute. To make it realistic, a palm-sized membrane can purify a coffee cup full of the solution in a second. If this technology is commercialized, it is expected to be useful in marine pollution situations.

The research, which was funded by the Korea Research Foundation, was published in Nanoscale, a renowned journal of nanotechnology.