“Magnetic Nanoparticles Pull Valuable Elements from Water Sources”

Earth-friendly process may help make critical materials sourcing economically feasible in the U.S.

Karyn Hede, PNNL

“RICHLAND, Wash.—A clever idea to use magnetic nanoparticles to capture valuable materials from brines has blossomed into industrial-scale pilot projects that could help make the U.S. a producer of critical minerals used in electronics and energy production. Today, most of these minerals are obtained from international sources, many of which are high-conflict regions.

“The patent-pending technology, developed at the U.S. Department of Energy’s Pacific Northwest National Laboratory, has been licensed exclusively by Moselle Technologies, a start-up business that is piloting the technology in several U.S. and international locations. 

“Together, PNNL and Moselle have successfully competed for technology development funding, including two Cooperative Research and Development Awards and a 2021 DOE Advanced Manufacturing Office award, to advance the process for capturing strategically important elements from water sources. 

“The core nanoparticle consists of a form of iron oxide better known as magnetite. This core particle is used to anchor the adsorbent shell that selectively binds the compounds of interest. That’s the key to the patented technology. The nanoparticles can be introduced into brines from geothermal plants, produced water, mineral mining effluent, and seawater, where they latch onto free floating target compounds. When exposed to a magnet, the nanoparticle’s iron core behaves like iron filings do in the classic science experiment—they migrate toward the magnet, along with the critical material to which they are bound, and can be filtered from the brine. The technology is being adapted for the capture of lithium, a versatile lightweight metal perhaps best known for its roles in battery technology.

“Current approaches for lithium extraction from water, for example, require a processing step that pumps large volumes of water, thousands of gallons a minute, through an ion exchange filtration system, making it both energy intensive and expensive,” said Pete McGrail, PNNL laboratory fellow and recognized expert on rare earth metal recovery technology. “Our nanotechnology process allows us to miniaturize everything and removes the need for massive ion exchange separators required in other processes. It’s quite simple. Within a few minutes, virtually all of the lithium has been pulled from the solution by molecular collisions with our sorbent and can then be removed with a magnet where its easily collected and purified…”


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