Fueling nuclear reactors with uranium harvested from the ocean could become more feasible because of a material developed by a team led by the Department of Energy's Oak Ridge National Laboratory. The combination of ORNL's high-capacity reusable adsorbents（吸附劑） and a Florida company's high-surface-area polyethylene（聚乙烯） fibers creates a material that can rapidly, selectively and economically extract valuable and precious dissolved metals from water. The material, HiCap, vastly outperforms today's best adsorbents, which perform surface retention of solid or gas molecules, atoms or ions. HiCap also effectively removes toxic metals from water, according to results verified by researchers at Pacific Northwest National Laboratory.
"We have shown that our adsorbents can extract five to seven times more uranium at uptake（攝取） rates seven times faster than the world's best adsorbents," said Chris Janke, one of the inventors and a member of ORNL's Materials Science and Technology Division.
Results were presented August 21 at the fall meeting of the American Chemical Society in Philadelphia.
HiCap effectively narrows the fiscal gap between what exists today and what is needed to economically extract some of the ocean's estimated 4.5 billion tons of uranium. Although dissolved uranium exists in concentrations of just 3.2 parts per billion, the sheer volume means there would be enough to fuel the world's nuclear reactors for centuries.
The goal of extracting uranium from the oceans began with research and development projects in the 1960s, with Japan conducting the majority of the work. Other countries pursuing this dream include Russia, China, Germany, Great Britain, India, South Korea, Turkey and the United States. Many adsorbent materials have been developed and evaluated, but none has emerged as being economically viable.
What sets the ORNL material apart is that the adsorbents are made from small diameter, round or non-round fibers with high surface areas and excellent mechanical properties. By tailoring the diameter and shape of the fibers, researchers can significantly increase surface area and adsorption capacity. This and ORNL's patent pending technology to manufacture the adsorbent fibers results in a material able to selectively recover metals more quickly and with increased adsorption capacity, thereby dramatically increasing efficiency.