Very Small Offers Big Cleanup Potential
EPA Researcher Developing Remediation Technology Using Nanomaterials
EPA scientists are exploring ways to use some very small materials to clean up some very big environmental problems. Research chemist Dr. Souhail Al-Abed and his colleagues have synthesized activated carbon with nanoparticles of iron/palladium bimetallic to produce a new nano-scale treatment to clean up pollutants. The new, tiny technology is offering promise where conventional technologies have been limted in detecting, treating, removing, and preventing environmental contaminants.
The research is proving particularly useful in dealing with PCBs, a family of persistent organic chemicals that have been linked to a host of dangerous health effects, including cancer. Dr. Al-Abed and his research group found that infusing the carbon with nanoparticles not only made it more effective at adsorbing contaminants, but also degraded the PCBs to less harmful compounds.
The carbon by itself is small and porous, making it effective at trapping and isolating PCBs. This means there are lots of spaces between the granules in the same way there are lots of spaces between pebbles in a pail. The more spaces, the more surface area is available for adsorption or chemical reactions. Infusing the activated carbon with the nanomaterials made it even more powerful as a cleaning technology and offers great promise in improving EPA's efforts to clean up sites contaminated with compounds such as PCBs.
"On the basis of our observations, a new strategy and concept of a 'reactive' cap/barrier composed of reactive activated carbon was proposed as a new environmental risk management option for PCB-contaminated sites," explains Dr. Al-Abed
Results of Dr. Al-Abed's work, published in the January 2009 issue of Environmental Science and Technology, are leading to some innovative practices in pollution control. For example, EPA is developing caps, or barriers, that contain and degrade PCBs during remediation, both at the contaminated site and the surrounding area to which contamination has spread.
Dr. Al-Abed is a research chemist at EPA's National Risk Management Research Laboratory in Cincinnati, Ohio. The paper by Dr. Al-Abed and colleagues, first published online in 2008, received a 2nd runner-up award for best technical paper of the year by the Environmental Science and Technology editors based on the expectation of its impact in the field.
Dr. Al-Abed's research has contributed to our understanding of many challenging environmental problems and to the development of cleanup strategies. His research activities include:
- Using electrochemical methods and bimetallic nanomaterials in the remediation of contaminated soils and sediments
- Fate and transport of nanomaterials in the environment
- Removal of heavy metals from aqueous waste streams
- Development of methodical leach tests for waste evaluation
Hyeok Choi, Shirish Agarwal, Souhail R. Al-Abed. (2009). "Adsorption and Simultaneous Dechlorination of PCBs by GAC Impregnated With ZVI/Pd Bimetallic Particles: Mechanistic Aspects and Reactive Capping Barrier Concept." Environmental Science and Technology, 43(2): 488-493.