The lanthanides and other rare earth elements (REEs) aren’t really “rare” in the strict sense, but they are quite difficult to separate and purify from the other materials with which they’re usually found. Because of the great value and utility of these metals for many purposes, including electronics, computing, and various industrial processes that rely on their unique electronic and chemical properties, that difficulty is a major problem.
Most current processes for REE separation and purification involve organic and acidic materials, making them both energy-intensive and environmentally unfriendly. Finding better separation techniques is therefore a pressing challenge. Researchers from the University of Chicago, Northwestern University, and Argonne National Laboratory took inspiration from nature to examine a new possibility for lanthanide separation. Their work was published in Science Advances.
Noting that ion channels in cell membranes are capable of separating ions across cell membranes with great efficiency, speed and selectivity, the investigators chose to model this process with chemically functionalized inorganic membranes to see if REE purification could be accomplished in a similar way. They constructed two-dimensional angstrom-scale artificial ion channels using MoS2 nanosheets that were covalently functionalized with acetic acid to generate MoS2-COOH membranes for lanthanide ion separation.
The ion transport process was studied using a variety of tools, including electron microscopy, infrared spectroscopy, molecular dynamics simulations and X-ray absorption spectroscopy and X-ray diffraction studies. Data were collected at the DuPont-Northwestern-Dow Collaborative Access Team 5-BM-D beamline at the Advanced Photon Source, a U.S. Department of Energy (DOE) user facility at DOE’s Argonne National Laboratory.
Read more on Argonne website