Navigation Links
New filtering technology has environmental, industrial applications
Date:11/18/2008

WEST LAFAYETTE, Ind. - Materials engineers have created a new type of membrane that separates oil from water and, if perfected, might be used for environmental cleanup, water purification and industrial applications.

The new technology would last longer than conventional filters for separating oil from water and works by attracting water while beading oil, traits that are usually mutually exclusive. Researchers attached the material to a glass filter commonly used in laboratory research.

"We take mixtures of oil dispersed in water and run them through these filters, and we are getting 98 percent separation," said Jeffrey Youngblood, an assistant professor of materials engineering at Purdue University. "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."

Findings were detailed in a paper that appeared online in October in the Journal of Colloid and Interface Science. The paper, which was written by Youngblood and materials engineering doctoral student John A. Howarter, also will appear in an upcoming print edition of the journal.

The findings demonstrate how an oily substance called hexadecane beads up on the membrane while water passes through.

The membrane consists of a layer of material called 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. This "oil coalescence filter" is needed to prevent oil from reaching the reverse osmosis membrane, which is ruined by oil. These conventional oil coalescence filters, however, must be replaced regularly. As water flows through the system, oil sticks to the filters, eventually rendering them ineffective.

The new technology, however, would not need to be replaced as frequently 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.

"When the oil-in-water dispersion contacts the filter surface, the oil coalesces to form big droplets. If the mixture is poured onto the filter, the oil forms on top of the material like a layer of cream," Youngblood said.

When a fluid lands on the surface of the material, it forms beads having a distinctive curvature determined by the "contact angle" of the substance. The higher the contact angle, the more a material is likely to form beads. Lowering the contact angle enough prevents substances from beading.

"This material maximizes oil's contact angle while minimizing water's contact angle, allowing water to flow through a filter while holding back the beaded oil," Youngblood said.

A key advantage of the new approach over some conventional methods is that it separates oil from water without using "nanoporous" filters. Filters containing extremely small pores require the water to be pushed through at high pressure, which consumes energy.

"One big problem is that if you are forcing stuff through very small pores it takes a lot of pressure," Youngblood said. "As the pores go down in size, the pressure goes way up. So, ideally you would want to use microfiltration instead of nanofiltration."

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

"Microfiltration ordinarily works well to remove particles but really for nothing else, meaning it will not remove oil from water," Youngblood said. "The pores are just too large, and the oil passes right through."

The new material, however, efficiently separates oil from water even though the pores are large, he said.

The membranes are said to be amphiphilic, meaning they are made of molecules with two ends - one end attracts water while the other end attracts oils and grease.

Future work may explore whether the filter works for solutions containing mostly oil and small amounts of water. Because crude oil extracted in commercial drilling operations initially contains some water, such a filter might have applications in the oil industry. Future research also will involve finding a substitute for the glass filters, which are not practical for commercial membranes.

"You would probably use fiberglass, but we are also looking at other technologies, such as a new nylon that has the right properties," Youngblood said.

A patent is pending on the technology.

The same technology also might be used to create antifogging goggles and self-cleaning eyeglasses by not allowing water to form beads on surfaces. In previous work by the same researchers, self-cleaning and antifogging behavior has been demonstrated in experiments using glass surfaces coated with the material. Eyeglasses and goggles used by skiers are two obvious potential applications, along with automotive windshields.


'/>"/>

Contact: Emil Venere
venere@purdue.edu
765-494-4709
Purdue University
Source:Eurekalert  

Related biology news :

1. High blood pressure takes big toll on small filtering units of the kidney
2. Increasing nitrogen pollution overwhelms filtering capability of streams
3. NIST, NCI bring web 2.0 tools to nanotechnology standards effort
4. e-Smart Technologies to Introduce Next Generation I AM Smart Card Technology at Cartes 2008 in Paris
5. Cost-effective farm waste-to-energy technology focus of research
6. Nanotechnology boosts war on superbugs
7. Europe rallies behind nanotechnology to wean world from fossil fuels
8. Human Microbiome Project awards funds for technology development, data analysis and ethical research
9. Genetic Engineering & Biotechnology News reports on growing role of molecular diagnostics
10. So-called sandfish could help materials handling and process technology specialists
11. Breakthrough optical technology to assess colon cancer risk, accuracy
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
New filtering technology has environmental, industrial applications
(Date:1/22/2016)... , January 22, 2016 ... the addition of the  "Global Behavioral ... offering. --> http://www.researchandmarkets.com/research/4lmf2s/global_behavioral ) ... "Global Behavioral Biometric Market 2016-2020"  report ... Research and Markets ( http://www.researchandmarkets.com/research/4lmf2s/global_behavioral ) has ...
(Date:1/20/2016)... --  MedNet Solutions , an innovative SaaS-based eClinical technology ... is pleased to announce the attainment of record-setting corporate ... of the company,s laser focus on (and growing international ... comprehensive, easy-to-use and highly affordable cloud-based technology platform. ... growth achievements in 2015 include: , Record ...
(Date:1/13/2016)... New York , January 13, 2016 ... Market Research has published a new market report titled ... Growth, Trends, and Forecast, 2015 - 2023. According to the ... in 2014 and is anticipated to reach US$1,625.8 mn ... 2015 to 2023. In terms of volume, the biometric ...
Breaking Biology News(10 mins):
(Date:2/9/2016)... PA (PRWEB) , ... February 09, 2016 , ... Tunnell ... Europe. Based in Paris, he will focus on acquiring new accounts and work ... met. , “Fred brings to our European clients more than 15 ...
(Date:2/9/2016)... , Feb. 9, 2016  DNAtrix, a ... for cancer, announced that its lead product, ... Commission as an orphan medicinal product for ... form of glioma, strikes approximately 25,000 people ... http://photos.prnewswire.com/prnh/20160208/330986LOGO --> ...
(Date:2/9/2016)... , Feb. 9, 2016 BERG, a ... biological research approach, has announced the appointment of ... and Chief Operating Officer. Haddock brings to BERG ... including 12 years in senior financial functions at ... in business organizational management. Niven ...
(Date:2/8/2016)... , Feb. 8, 2016  CytRx Corporation ... development company specializing in oncology, today announced that ... security agreement with Hercules Technology Growth Capital, Inc. ... $40 million in financing. --> ... first $25 million of financing under the loan ...
Breaking Biology Technology: