Shining light on the separation of rare earth metals

Shining light on the separation of rare earth metals
Researchers built a constellation of complexes that point the way to molecular structures and associated models that can improve the efficiency of light-driven chemistry to separate cerium. Credit: Journal of American Chemical Society

Inside smartphones and computer displays are metals known as the rare earths. Mining and purifying these metals involves waste- and energy-intense processes. Better processes are needed. Previous work has shown that specific rare earth elements absorb light energy that can change their chemical behavior and make them easier to separate. Now, researchers have revealed how certain molecular structures can improve the efficiency of this light-driven chemistry to separate cerium, a rare earth element.

The 17 are chemically similar. Methods used to purify the desired elements from natural sources produce massive quantities of waste. Purifying one ton of a rare earth element creates tons of acidic and radioactive waste. The processes are also energy intensive. Knowing how to efficiently use light to selected rare earths could reduce waste and lower costs. New methods for recycling europium and other rare earths using light-driven chemistry is also an important direction to diversify the supply chain for these critical elements.

Rare earth -containing materials are irreplaceable and used widely in technologies such as lighting, displays, biological sensors, lasers, electric cars, and smartphones. However, rare earth separations by conventional solvent extraction or ion-exchange chromatography methods are time-consuming, require substantial cost, and are unsustainable. Photochemical-based separation has been examined as a promising preprocessing step to separate redox-active rare earths, especially europium, from mined ore mixtures.

New methods for recycling of europium and other rare earths using photochemistry is also an important direction for diversifying the . Among the , several members, such as cerium, samarium, europium, and ytterbium, absorb light through relevant electronic 4f-5d transitions. Current photoredox separations methods are not practical because of their need for intense light sources. Controlling and exploiting the 4f-5d transitions for these elements is important for achieving applications in photoredox rare earth separations. Recently, a group of researchers from the University of Pennsylvania and the University of Buffalo developed a combined experimental and computational study to understand and control the photophysics of luminescent cerium complexes.

The team designed and synthesized a series of cerium(III) complexes that allowed for identification of key structural features that enabled predictive and tunable quantum yields, and therefore brightness. Moreover, the team performed comprehensive computational analyses of guanidinate-amide and guanidinate-aryloxide luminescent cerium(III) complexes. The computational data afforded rationalization of the differences in Stokes shifts (luminescent colors) of these compounds. These quantitative structure-luminescence models are expected to contribute to the photoredox separations of rare--containing products whose 4f-5d electronic transitions can be tuned and exploited in the visible and ultraviolet range for efficient, green, and potentially low cost photochemical-based separations.


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More information: Yusen Qiao et al. Understanding and Controlling the Emission Brightness and Color of Molecular Cerium Luminophores, Journal of the American Chemical Society (2018). DOI: 10.1021/jacs.7b13339
Citation: Shining light on the separation of rare earth metals (2018, October 18) retrieved 21 October 2019 from https://phys.org/news/2018-10-rare-earth-metals.html
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KBK
Oct 18, 2018
Then there is the bunga plant in Germany, during the second world war. it used more electricity than Berlin.

They say it was used to produce rubber, but it is on record for never producing even an ounce of rubber.

What it was doing, was making weapons grade nuclear materials for bombs. It was using chemistry and light. Filtered, polarized lights, in early versions of laser-like devices. working against a chemical stew/fluid

This produced fissionable materials, concentrated enough for actual use.

The German Reichcommand never surrendered. Their name and presence is no where to be seen in the 1945 records, and photos. Fact.

They sold off their science and scientists to the Russians and the USA. they sold off the fissionable materials to the USA, which did not have any for their two bombs (FACT-look it up)

They escaped, and also entered US black technology programs. Thousands of them.

The USA has a deep a Nazi/fascist oligarchy problem.

Know your history....

KBK
Oct 18, 2018
What I'm saying, is that this light and chemistry method was done over 70 years ago, and played a huge part in the ending of the second world war,

And that this being over 70 years old, already, it makes you wonder what the unlimited funds of the 26+ TRILLION dollars is doing and has done, in all those black programs? (FACT) (OIG of the us government is the one finding and reporting on the missing 26 trillion in funds)(those accountants were the ones killed in the pentagon on 9/11, one day after Rumsfeld's press conference on their initial findings of trillions gone missing)

You've got a two tier technology system.

One, The ridiculously advanced hidden black technology end of the pool, and two...the pathetic (in comparison) open technology that the public is aware of.

So look this stuff up. please. Refute me. Make it wrong, make it crazy, make it a crackpot statement.

Good luck with that.

Oct 18, 2018
Oh, K! You forgot(?) to include this was all at the behest of the theosophist conspiracy to conquer the Earth's surface from their secret flying-saucer bases inside the Hollow Earth!

god bless Joseph Stalin and Máo Zédōng for thwarting that nefarious plot!

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