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 'Y' a protein unicorn might matter in glaucoma
23.10.2017 | Georgia Institute of Technology

nachricht Microfluidics probe 'cholesterol' of the oil industry
23.10.2017 | Rice University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Salmonella as a tumour medication

HZI researchers developed a bacterial strain that can be used in cancer therapy

Salmonellae are dangerous pathogens that enter the body via contaminated food and can cause severe infections. But these bacteria are also known to target...

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

3rd Symposium on Driving Simulation

23.10.2017 | Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

 
Latest News

Microfluidics probe 'cholesterol' of the oil industry

23.10.2017 | Life Sciences

Gamma rays will reach beyond the limits of light

23.10.2017 | Physics and Astronomy

The end of pneumonia? New vaccine offers hope

23.10.2017 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>