Skip Navigation

National Institute of Environmental Health Sciences

 

Research Brief 211

Superfund Research Program

A New Solar-Powered Approach for Groundwater Decontamination

View Research Brief as PDF (426KB)

Release Date: 07/03/2012Icon to indicate you can subscribe/listen via iIunessubscribe/listen via iTunes   , download (858KB) , Transcript (161KB)

Trichloroethylene (TCE), a chlorinated hydrocarbon that is used as an industrial solvent and degreaser, is one of the most common soil and groundwater contaminants in the United States. A research team led by Akram Alshawabkeh, Ph.D., from the Northeastern University Superfund Research Program has developed a new, low-cost strategy for remediating this contaminant.

In a study published in the February 2012 edition of Environmental Science & Technology, the researchers outline a novel method that uses iron ions (Fe(II)) along with a palladium (Pd) catalyst to enhance oxidative degradation of TCE, which typically occurs as a side reaction during traditional TCE hydrodechlorination. Their method is particularly suited for sustained treatment of aquifers since a solar-powered system can be engineered for in situ implementation.

To develop the method, Songhu Yuan, Ph.D., a visiting professor from the China University of Geosciences in Wuhan, China, together with Xuhui Mao, Ph.D., a postdoctoral research associate at Northeastern University, applied mixed metal oxide electrodes to simulated TCE-contaminated groundwater to generate H2 in a lab-controlled environment. They added palladium powder to catalyze the reaction, which degraded TCE into ethane and other byproducts. Without the addition of Fe(II), 40% of the TCE was degraded within 80 minutes. However, when Yuan added Fe(II), 95% of the TCE was degraded within the same amount of time. He found that adding Fe(II) shifts the process of TCE decontamination from hydrodechlorination (a reduction process) to a more rapid oxidative reaction. This shift was most effective when high concentrations of iron (about 10 mg/L) were present and the pH of the water was low. This is the first time a research group has reported on palladium’s ability to indirectly catalyze an oxidation process for groundwater remediation.

The researchers believe that this may be a low-cost and highly efficient method to remediate contaminated groundwater. They used the results to devise a three-electrode Pd-catalytic remediation system with automatic pH-regulation, which they are currently evaluating. (click on image to enlarge) They are also developing an in-well solar-powered system for field testing.

diagram of Pd catalyzes the degradation of TCE. The addition of Fe(II) ions  shifts the reaction to a more rapid oxidative reaction.

For More Information Contact:

Akram N Alshawabkeh
400 SN
360 Huntington Ave.
Boston, MA 02115-5000
Tel: (617) 373-3994
Email:

To learn more about this research, please refer to the following sources:

  • Yuan, Songhu, Xuhui Mao, and Akram N. Alshawabkeh. 2012. Efficient degradation of TCE in groundwater using Pd and electro-generated H2 and O2: A shift in pathway from hydrodechlorination to oxidation in the presence of Ferrous ions. Environmental Science & Technology.   46(6):3398-3405. doi:10.1021/es204546u