Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

High-tech sieve sifts for hydrogen

07.02.2006


New polymer use may yield cheaper way to separate hydrogen from impurities

Whether it’s used in chemical laboratories or the fuel tanks of advanced automobiles, hydrogen is mostly produced from natural gas and other fossil fuels. However, to isolate the tiny hydrogen molecules, engineers must first remove impurities, and the currently available methods can require substantial equipment or toxic chemicals.

Now, in the Feb. 3 issue of the journal Science, engineers have announced the development of a simpler, safer material that can potentially assist, and in some places replace, existing processing methods. The rubbery, plastic film, similar to membranes already in use in biomedical devices, has applications for isolating not only hydrogen, but also natural gas itself.



"Our team originally set out to design membranes to purify hydrogen produced from coal," said co-author and National Science Foundation awardee Benny Freeman of The University of Texas. "We felt that a good improvement would be to design membranes more permeable to impurities than to hydrogen," he added. Until now, existing membranes had the opposite property--they were more permeable to hydrogen than to impurities.

Freeman collaborated in this research with colleagues at both The University of Texas at Austin and the Research Triangle Institute in Research Triangle Park, N.C.

Hydrogen is commonly generated from natural gas in a process called steam reforming, wherein treatments with hot steam convert methane into a gaseous mixture consisting of mainly carbon dioxide (CO2), carbon monoxide (CO) and hydrogen.

In a phenomenon that at first seems counterintuitive, larger gas molecules like CO2, and polar molecules, pass through the new film, while the much smaller hydrogen molecules stay behind.

The membrane works because the molecules in its structure have relatively "positive" parts that attract electrons and relatively "negative" parts that repel electrons. CO2 has some of these "polar" characteristics, so it is attracted to the membrane, dissolving into it as salt dissolves into a glass of water.

The molecules diffuse through the membrane at a rate that increases as more polar molecules become entrenched in the rubbery polymer, the researchers found. Even when the membrane is saturated with impurities, the polar properties continue to funnel the undesirable molecules along at a faster rate than for hydrogen, retaining most hydrogen molecules on the upstream side.

Unlike other methods, the new "reverse-selective" process can capture hydrogen at a pressure close to that of the incoming gas. This is a primary advantage for the membrane because high pressure is important for transport of the gas, and many applications, yet adds significant costs.

"The best you can do in terms of pressurization for any of these processes is make hydrogen at or near feed pressure," said Freeman. Conventional membranes, which would allow hydrogen to pass through while holding other gasses back, would decrease hydrogen pressure, he added.

While other hydrogen extraction methods still have advantages, the researchers believe there is great potential for future approaches to be hybrid processes that incorporate the new membrane within established systems.

Joshua Chamot | EurekAlert!
Further information:
http://www.nsf.gov

More articles from Life Sciences:

nachricht Molecular evolution: How the building blocks of life may form in space
26.04.2018 | American Institute of Physics

nachricht Multifunctional bacterial microswimmer able to deliver cargo and destroy itself
26.04.2018 | Max-Planck-Institut für Intelligente Systeme

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Why we need erasable MRI scans

New technology could allow an MRI contrast agent to 'blink off,' helping doctors diagnose disease

Magnetic resonance imaging, or MRI, is a widely used medical tool for taking pictures of the insides of our body. One way to make MRI scans easier to read is...

Im Focus: BAM@Hannover Messe: innovative 3D printing method for space flight

At the Hannover Messe 2018, the Bundesanstalt für Materialforschung und-prüfung (BAM) will show how, in the future, astronauts could produce their own tools or spare parts in zero gravity using 3D printing. This will reduce, weight and transport costs for space missions. Visitors can experience the innovative additive manufacturing process live at the fair.

Powder-based additive manufacturing in zero gravity is the name of the project in which a component is produced by applying metallic powder layers and then...

Im Focus: Molecules Brilliantly Illuminated

Physicists at the Laboratory for Attosecond Physics, which is jointly run by Ludwig-Maximilians-Universität and the Max Planck Institute of Quantum Optics, have developed a high-power laser system that generates ultrashort pulses of light covering a large share of the mid-infrared spectrum. The researchers envisage a wide range of applications for the technology – in the early diagnosis of cancer, for instance.

Molecules are the building blocks of life. Like all other organisms, we are made of them. They control our biorhythm, and they can also reflect our state of...

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

World's smallest optical implantable biodevice

26.04.2018 | Power and Electrical Engineering

Molecular evolution: How the building blocks of life may form in space

26.04.2018 | Life Sciences

First Li-Fi-product with technology from Fraunhofer HHI launched in Japan

26.04.2018 | Power and Electrical Engineering

VideoLinks
Science & Research
Overview of more VideoLinks >>>