Uranium removal
1 Sep 2005
Decontamination of radionuclides from metallic and other surfaces contaminated by radiological incidents is a major environmental challenge.
Brookhaven scientist A.J. Francis, assisted at the Lab by Cleveland Dodge and by Gary Halada at SBU, led the effort in developing the innovative and improved process for decontaminating metal surfaces and other materials.
The research team developed an environmentally friendly green-chemistry process that uses all naturally occurring materials – citric acid, common soil bacteria, and sunlight. Present methods of removing uranium from contaminated metal surfaces include sand blasting, chemical extraction, and electro-chemical dissolution. But these methods generate secondary waste streams, creating additional disposal problems.
“In the event of a radiological incident, such as a ‘dirty bomb,’ this technology can be used to clean up contaminated materials,” Francis said. “It will also treat the secondary waste generated from the treatment process, resulting in waste minimisation. It is a comprehensive process.”
Using the National Synchrotron Light Source, a source of intense x-rays, ultraviolet and infrared light at Brookhaven Lab, the researchers systematically examined the contaminated materials at the molecular scale and the association of uranium before and after treatment with citric acid formulations. The efficiency of uranium removal ranged from 68% to 94%, depending on the age and extent of corrosion.
Wastewater generated from the decontamination process was subjected to biodegradation followed by photodegradation, which minimised the generation of secondary waste and allowed the uranium to be recovered. This process, which has been patented, can also be used to remove toxic metals and radionuclides from contaminated soils, wastes, and incinerator ash.
