For those of you who have natural gas in your home, the smell of rotten eggs is a sign you need to get out of there and call the proper authorities. But in other combustible materials like gasoline, airplane fuel, oil, or even homemade bombs, the key ingredient—alkane fuel—is extremely difficult to detect, meaning leaks or attacks are impossible to catch before it’s too late.
Now, researchers from the University of Utah have developed a solution to this potentially deadly problem: A material that can detect fuel leaks and fuel-based explosives from small traces of alkane fuel vapor.
Why is alkane fuel so hard to detect?
Alkane fuel vapor is both odorless and colorless—thus why natural gas, which is composed of an alkane known as methane, has a harmless chemical known as mercaptan added to it, so that leaks can be detected. However, mercaptan is not added to things like alkane fuel-based weapons (why would a terrorist want people to smell an oncoming attack?), meaning detection by scent is a challenge.
Further, alkanes are inert at room temperature, meaning they are quite unreactive and stable—crude oil, for example, consists of alkane molecules that haven’t been chemically changed for millions of years—which makes their detection in the field quite challenging. In fact, the conventional method of detecting the presence of alkane fuel vapor requires an oven-sized instrument in a laboratory.
“It’s not mobile and very heavy,” said University of Utah materials science and engineering professor Ling Zang in a Phys.org statement. “There’s no way it can be used in the field. Imagine trying to detect the leak from a gas valve or on the pipelines. You ought to have something portable.”
But unfortunately, small, portable chemical sensors for this purpose currently don’t exist.
And so Zang’s team came up with a solution, involving a kind of fiber composite where two nanofibrils transfer electrons back and forth when alkanes aren’t present, according to the paper in ACS Sensors.
“These are two materials that interact well together by having electrons transferring from one to another,” said Ben Bunes, a postdoctoral fellow in the University of Utah’s materials science and engineering department. “When an alkane is present, it sticks in between the two materials, blocking the electron transfer between the two nanofibers.”
Once this happens, a detector is signaled that alkane vapor is present. One company known as Vaporsens designed such a detector, which also includes 15 other sensor materials to identify a broad range of chemicals outside of alkanes. This item should be on the market in around a year and a half, according to Zang.
A world of difference
The potential security benefits of this device are massive–for example, an alkane-based fuel (diesel) was used to make the bomb used in the 1995 Oklahoma City bombing, so this sensor technology could have averted the tragedy had it existed at the time.
But there are other extremely important uses outside of stopping terrorism. For example, airplane fuel leaks are difficult to detect in real time. And leaks in oil pipelines could lead to water contamination and environmental devastation if not detected early enough.
This device, then, could save a large number of lives, human or otherwise—a revolution for the generally stable substance.
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Image Credit: Dan Hixson/University of Utah College of Engineering
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