Featured Research

from universities, journals, and other organizations

INEEL Researchers Separate The Good From The Bad With Durable, Tailorable Membranes

Date:
August 27, 1999
Source:
Idaho National E & E Laboratory
Summary:
Researchers at the Department of Energy's Idaho National Engineering and Environmental Laboratory are creating durable membranes that can be specially tailored to separate different chemicals from water.

While some separations leave you lonely, other separations leave you glad: they clean up contaminated water, reduce hazardous waste and refine useful chemicals and gases. Many of these separations depend on the help of membranes that allow one substance to pass through and hold back the rest.

Researchers at the Department of Energy's Idaho National Engineering and Environmental Laboratory are creating durable membranes that can be specially tailored to separate different chemicals from water. Fred Stewart, a chemist at the INEEL, presented his group's work at the 218th National Meeting of the American Chemical Society on Aug. 24 in New Orleans, La.

Membranes are used often in both the DOE and in industrial applications. While the DOE is mainly concerned with removing hazardous and radioactive contamination from waste and other liquids, industries delve into water treatment, production of industrial gases and pharmaceutical manufacturing. Many applications require membranes that are tougher, more efficient and more versatile than current membranes.

Membranes decontaminate by filtering substances selectively. Stewart said, "Let's say I've got this thousand gallon drum of something nasty in water, and 5 percent of it is the nasty stuff. If I can pull out the 50 gallons of hazardous substance and recover 950 gallons of water, I've drastically reduced the amount of waste I have to dispose of. Industries are very interested in waste minimization."

The DOE is also interested in waste minimization, but the substances that contaminate DOE sites are problematic for conventional membranes. "The state of the art in membranes is organic membranes, all carbon- or silicon-based. They have very limited utility within the DOE," said Stewart. "These membranes generally can't withstand the chemical and thermal stresses that are placed on them. They also have insufficient stability when exposed to high radiation fields."

Industrial applications require membranes that are stable at high temperatures as well. "Most membranes disintegrate starting at about 150 degrees Celsius, which is low for industrial uses," said Stewart. The membranes Stewart and his group work on are stable up to 300 degrees Celsius, three times the temperature of boiling water.

Stewart's membrane is a hybrid of organic and inorganic molecules. The organic molecules allow water and dissolved substances to interact with the membrane, and the inorganic molecules provide more stability than what most organic-only membranes have.

The organic molecules are chosen based on what dissolved substance will be separated from the water. The inorganic molecules -- alternating phosphate and nitrogen molecules -- form a polymer backbone to which the organic molecules are attached. Single lengths of the backbone molecules, which are akin to wooden slats on a deck, can be linked to each other in a method called cross-linking. This creates a sturdy, micro-sized lattice (the finished deck) that is then placed on a support (the deck's feet).

The holes within the cross-linked polymer lattice allow molecules to flow through. "A Ziplock baggy is a cross-linked polymer," said Stewart. "We want something as durable as a Ziplock baggy -- then maybe we can dispense with the support. Without cross-linking, we think the polymer gets sucked into the support, because the membrane stops working after a few days."

These membranes -- called polyphosphazene membranes -- have two advantages for the researchers. The number of cross-links in the backbone can be varied, and they can add whatever organic molecules they want to the polymer backbone. These qualities allow the researchers to tailor the membranes' selectivity and to withstand temperature, pH, and radiation.

To deal with this, Stewart and his colleagues are developing computer-based models of polymer chemistry. "There are limitations to what a polymer will do," he said. "We're learning how to theoretically predict what a polymer will do so when a customer comes in and says, 'This is what I need,' we'll be able to look at the basic characteristics of their feed stream -- what they'll be separating from what -- and match that up with the right polymers."

Although the membranes being developed at the INEEL might be too expensive for large-scale water treatment, they are just what the DOE needs to clean up the nuclear weapons and nuclear energy research legacy. Stewart said, "One problem DOE has with cleaning up is nothing already available works all that well."

This work has been funded by INEEL discretionary research funds and DOE programs for Environmental Systems Research and Environmental Management. INEEL celebrates its 50 year anniversary in 1999. The national laboratory is operated for the U.S. Department of Energy by Lockheed Martin Idaho Technologies Company.


Story Source:

The above story is based on materials provided by Idaho National E & E Laboratory. Note: Materials may be edited for content and length.


Cite This Page:

Idaho National E & E Laboratory. "INEEL Researchers Separate The Good From The Bad With Durable, Tailorable Membranes." ScienceDaily. ScienceDaily, 27 August 1999. <www.sciencedaily.com/releases/1999/08/990827072003.htm>.
Idaho National E & E Laboratory. (1999, August 27). INEEL Researchers Separate The Good From The Bad With Durable, Tailorable Membranes. ScienceDaily. Retrieved October 1, 2014 from www.sciencedaily.com/releases/1999/08/990827072003.htm
Idaho National E & E Laboratory. "INEEL Researchers Separate The Good From The Bad With Durable, Tailorable Membranes." ScienceDaily. www.sciencedaily.com/releases/1999/08/990827072003.htm (accessed October 1, 2014).

Share This



More Matter & Energy News

Wednesday, October 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Japan Looks To Faster Future As Bullet Train Turns 50

Japan Looks To Faster Future As Bullet Train Turns 50

Newsy (Oct. 1, 2014) Japan's bullet train turns 50 Wednesday. Here's a look at how it's changed over half a century — and the changes it's inspired globally. Video provided by Newsy
Powered by NewsLook.com
US Police Put Body Cameras to the Test

US Police Put Body Cameras to the Test

AFP (Oct. 1, 2014) Police body cameras are gradually being rolled out across the US, with interest surging after the fatal police shooting in August of an unarmed black teenager. Duration: 02:18 Video provided by AFP
Powered by NewsLook.com
Raw: Japan Celebrates 'bullet Train' Anniversary

Raw: Japan Celebrates 'bullet Train' Anniversary

AP (Oct. 1, 2014) A ceremony marking 50 years since Japan launched its Shinkansen bullet train was held on Wednesday in Tokyo. The latest model can travel from Tokyo to Osaka, a distance of 319 miles, in two hours and 25 minutes. (Oct. 1) Video provided by AP
Powered by NewsLook.com
Robotic Hair Restoration

Robotic Hair Restoration

Ivanhoe (Oct. 1, 2014) A new robotic procedure is changing the way we transplant hair. The ARTAS robot leaves no linear scarring and provides more natural results. Video provided by Ivanhoe
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins