Developing nations could soon be able to harness nuclear power from oceans as scientists have revealed advances that could make it possible.
Scientists have long known that uranium when dissolved in seawater combines with oxygen to form uranyl ions. These ions can be extracted from seawater using plastic fibers containing a compound called amidoxime into seawater. The uranyl ions essentially stick to the amidoxime. Once these plastic fibers become saturated, they are then chemically treated to free the uranyl, which then has to be refined for use in reactors just like ore from a mine.
However, that’s where the hurdle is. The practicality of this particular process depends on three major factors – how much uranyl sticks to the fibres, how quickly ions can be captured and how many times the fibers can be reused. Researchers at Stanford University have revealed that they have been working to improve all three variables associated with the process of extracting uranium from seawater – capacity, rate and reuse.
According to the team, they came up with a conductive hybrid fiber by incorporating carbon and amidoxime. By sending pulses of electricity down the fiber, they managed to alter the properties of the hybrid fibre such that it is able to collect more uranyl ions.
Scientists performed tests on amidoxime-carbon hybrid fibers and amidoxime fibres to test how much uranyl ions each type of fiber could hold before reaching saturation. They found that by the time the standard amidoxime fibre had become saturated, the amidoxime-carbon hybrid fibres had already adsorbed nine times as much uranyl and were still not saturated.
The hybrid fibers were able to hold three times as much uranyl during an 11-hour test using seawater from Half Moon Bay, about an hour from Stanford and had three times the useful lifespan of the standard amidoxime. Trace amounts of uranium exists in seawater, but efforts to extract that critical ingredient for nuclear power have produced insufficient quantities to make it a viable source for those countries that lack uranium mines.
A practical method for extracting that uranium, which produces higher quantities in less time, could help make nuclear power a viable part of the quest for a carbon-free energy future.
While the concentration of uranium are very tiny, considering the size of the oceans, there could be enough uranium to the point that its supply could be endless. Researchers belive that a practical way to extract uranium from seawater is needed to reduce the energy insecurity of nations that depend on nuclear power but lack uranium within their own borders. The research was published in the journal Nature Energy.