Rare earth elements are an integral part of many of today's electronic devices, serving as magnets, catalysts and superconductors. Unfortunately, these minerals are also ... well, rare, and thus very pricey. Recently, however, scientists discovered that some of them can be reclaimed from industrial wastewater, instead of being mined from the earth.
The researchers, from the Chinese Academy of Sciences, already knew that a nanomaterial known as nano-magnesium hydroxide (nano-Mg(OH)2) could remove some metals and dyes from wastewater. It was also known that the rare earth elements in wastewater tend to be very diluted, and thus quite difficult to remove in a practical, inexpensive fashion.
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After studying the manner in which nano-Mg(OH)2 works, the scientists proceeded to produce special flower-shaped nanoparticles of the material. In lab tests that replicated real-world conditions, these particles were able to capture over 85 percent of the rare earth elements diluted in water samples. By subsequently adjusting the pH, it was possible to then separate the captured minerals from the nano-Mg(OH)2.
“Recycling REEs from wastewater not only saves rare earth resources and protects the environment, but also brings considerable economic benefits,” the team stated in a paper on the research, which was recently published in the journal ACS Applied Materials and Interfaces.
Source: American Chemical Society