New research reveals way to detoxify dirt—zap it with lasers

September 7, 2017 by Allie Nicodemo
Credit: Colin/Flickr

To feed a growing population, our global food system relies on sufficient farmland. But over the past 40 years, one-third of arable land has been lost to erosion or sullied by pollution.

Man-made chemicals and fertilizers used to improve can persist in for years, making it less fertile over time. Antibiotics in seep out and also cause degradation. Oil spills and environmental disasters can impact large parcels of land. And all this is compounded by the sluggish pace at which new topsoil is formed—about 2.5 centimeters evert 500 years.

Currently, cleaning up soil is possible, but cumbersome. One method requires the dirt to be dug up, removed, and transferred to a treatment plant for decontamination. A better option would be to clean soil where it lies, but traditional techniques use water and chemical solvents that may dilute the toxins without truly getting rid of them.

Ming Su, an associate professor of chemical engineering at Northeastern, has developed a less costly and less labor-intensive way to decontaminate dirt. In a paper published this month in the Journal of Applied Physics, Ming describes his discovery—blasting soil with an can quickly break down and eradicate a type of pervasive pollutant.

This research came about because Su wanted to focus his lab on tackling an environmental problem. He had the idea to develop a new method for chemical decontamination, and noticed the price of an industrial system had dropped significantly in recent years, making it feasible for large-scale use. He purchased a benchtop laser with his startup fund from Northeastern and tested it out on soil that had been sullied by the Dichlorodiphenyldichloroethylene, or DDE.

A derivative of the notorious cancer-causing pesticide Dichlorodiphenyltrichloroethane, or DDT, DDE was ideal for this study because it glows when exposed to ultraviolet light, making it easy to spot, Su said. He found that when he used the infrared laser to blast DDE-contaminated soil, and then scanned the soil with ultraviolet light, there was no glowing residue. The toxin disappeared.

Su and his graduate students have filed an invention disclosure through Northeastern's Center for Research Innovation for the technology. He is planning to conduct more studies to determine whether lasers can blast away other types of soil contaminants. After that, the next step will be to collaborate with land and agriculture experts and scientists from the laser industry to put research to practice.

"One design would be a truck that has a lot of these laser beams coming out," Su said. "The lasers could be installed on a plow structure, so that a plow could dig into the ground and when a truck is moving, the laser can scan the whole area."

Explore further: Lasers zap decontaminates from soil

More information: Wenjun Zheng et al. Laser induced rapid decontamination of aromatic compound from porous soil simulant, Journal of Applied Physics (2017). DOI: 10.1063/1.4985813

Related Stories

Lasers zap decontaminates from soil

August 29, 2017

There might be a new and improved way to rid contaminated soil of toxins and pollutants: zap it with lasers. By directly breaking down pollutants, researchers say, high-powered lasers can now be more efficient and cheaper ...

Monitoring soil structure changes after compaction

June 19, 2017

Soil compaction is a global threat to soil ecosystem services, causing tremendous costs to society. The costs of soil compaction are borne by the cumulative loss of soil functionality (e.g. yield loss) following a compaction ...

Laser reveals water's secret life in soil

March 30, 2016

Most of us think nothing of rainfall or where it goes, unless it leads to flooding or landslides. But soil scientists have been studying how water moves across or through soil for decades. Daniel Hirmas, a professor at University ...

Writing an equation for soil success

November 23, 2016

Soil isn't one size fits all. It may look the same under your feet - but under a microscope, that's a different story. A plant's roots, tiny bugs - these things can tell one soil from another quite easily.

Recommended for you

How the Earth stops high-energy neutrinos in their tracks

November 22, 2017

Neutrinos are abundant subatomic particles that are famous for passing through anything and everything, only very rarely interacting with matter. About 100 trillion neutrinos pass through your body every second. Now, scientists ...

Enhancing the quantum sensing capabilities of diamond

November 22, 2017

Researchers have discovered that dense ensembles of quantum spins can be created in diamond with high resolution using an electron microscopes, paving the way for enhanced sensors and resources for quantum technologies.

Quantum internet goes hybrid

November 22, 2017

In a recent study published in Nature, ICFO researchers led by ICREA Prof. Hugues de Riedmatten report an elementary "hybrid" quantum network link and demonstrate photonic quantum communication between two distinct quantum ...

Lightning, with a chance of antimatter

November 22, 2017

A storm system approaches: the sky darkens, and the low rumble of thunder echoes from the horizon. Then without warning... Flash! Crash!—lightning has struck.

Study shows how to get sprayed metal coatings to stick

November 21, 2017

When bonding two pieces of metal, either the metals must melt a bit where they meet or some molten metal must be introduced between the pieces. A solid bond then forms when the metal solidifies again. But researchers at MIT ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.