We all know by now what rare earths are (REE, Rare Earth Elements), fundamental components for almost all modern technologiesgive it smartphone garlic hard disk of the computer. What we don’t know is how to separate them from the earth’s crust (but also from each other) in a simple way.
Therefore the scientists of the Penn Statel’University of Pennsylvania (United States), they thought to ask biology aid. Thanks to this they discovered a new mechanism by which bacteria can select between different rare earth elements, using the capacity of a bacterial protein to bond with another unit of itself, or dimerizewhen tied to certain rare earths, but prefer to remain a single unit, or monomerwhen related to others.
Currently, separating rare earths is complicated and very polluting
After fully understanding these mechanisms, researchers have found a way to separate rare earth metals (similar to each other) quickly, efficiently and at room temperature. This process promises to get to more efficient and greener mining and recycling practices. Moreover, it is applicable both to extract metals from rock and from discarded electronic devices.
The advantage over traditional methods is evident given that separating rare earths still requires the use of large quantities of toxic chemicals such as kerosene and phosphonates (much the same chemicals used in insecticides and herbicides) with dozens or even hundreds of steps to obtain individual oxides of REE of high purity.
A protein that binds lanthanides to calcium
The solution found by American scientists comes directly from nature thanks to a class of bacteria called methylotrophs, which are often found on plant leaves, soil and water. After isolating the protein lanmodulina from one of these bacteria they found that it was like no other in its ability to bind lanthanides (rare earths) to common metals such as calcium. Through later work they demonstrated that they were able to purify these elements as a group from dozens of other metals in mixtures that were too complex for traditional extraction methods.
Unfortunately, the lanmodulina it seems less effective at discriminating between individual rare earths. However, the concept of bond rare earths at a molecular interface it could also prove to be a winning approach for creating separations between REE, elements that are found next to each other in the periodic table. The goal appears to be within reach.
All the details of this important research have been published on ScienceDaily.
METALLIRARI.COM © SOME RIGHTS RESERVED