New filtering technique could be answer to toxic oil spills

November 19th, 2008 - 12:21 pm ICT by IANS  

Washington, Nov 19 (IANS) A new filtering membrane could be the long awaited answer to toxic oil spills, besides providing safer water and detoxifying industrial effluents.The new technology, designed by materials engineers, works by attracting water while beading oil, traits that are antagonistic.

“We take mixtures of oil dispersed in water and run them through these filters, and we are getting 98 percent separation,” said Jeffrey Youngblood, assistant professor of materials engineering at Purdue University and co-author of the study that reported the findings.

“This is pretty good because if you don’t modify the glass filters with our material essentially all the oil goes through. If you modify it with our material, then almost none of the oil goes through.”

The membrane comprises a layer of polyethylene glycol and each molecule is tipped with a Teflon-like “functional group” made with fluorine. Water molecules are attracted to the polyethylene glycol, yet pass through the Teflon-like layer, which acts as a barrier to the oil molecules.

The researchers have tested the material with solutions containing oil suspended in water, similar to concentrations existing in oil spills and other environmental cleanup circumstances.

“To clean up an oil spill, for example, you could run contaminated water through a bunch of these filters to remove the oil,” Youngblood said.

Such filters also might be used in other cleanup applications, such as removing oil from a ship’s bilge water or cleaning wastewater contaminated with oil.

The technology might be used in a water-purification technology called reverse osmosis, which now requires a “pre-filter” to remove oil, according to a Purdue release.

The new technology would not need frequently replacements, unlike existing filters, because oil does not stick to the filtration material. Instead, the oil droplets could be skimmed off through a commonly used industry technique called cross-flow filtration.

The new material contains pores between 10 and 174 microns, or millionths of a metre. Because the pores are relatively large, oil-contaminated water would not have to be pumped through.

The same technology also might be used to create antifogging goggles and self-cleaning eyeglasses by not allowing water to form beads on surfaces.

The findings are scheduled for publication in the Journal of Colloid and Interface Science.

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