Leaps?MPS: separation of group (IV) and lanthanide complexes using novel photoredox separation methods

The National Science Foundation's Division of Chemistry awarded a $243,780 Project Grant under the Mathematical and Physical Sciences (CFDA 47.049) program to Hawai'i Pacific University, effective September 1, 2025 through August 31, 2027. Under the Launching Early-Career Academic Pathways (LEAPS) initiative, Professor Mullane and her undergraduate students will develop novel photoredox-based separation methods for rare earth elements and early transition metals. The research will synthesize light-absorbing lanthanide and transition metal complexes to investigate ligand-metal interactions and their effects on light absorption and emission properties, with the goal of creating low-energy, selective separation techniques for metals with similar atomic radii and oxidation states.

Beyond the core scientific research, this award delivers significant educational and workforce development products, including hands-on training for undergraduate researchers in air-sensitive synthesis techniques, electrochemistry, and advanced characterization methods. The project addresses a critical national interest in reducing U.S. dependence on imported rare earth elements—currently 80% sourced from China—by advancing recycling capabilities for decommissioned materials used in wind turbines, LEDs, and rechargeable batteries. Research findings will contribute to the broader photoredox chemistry knowledge base while building STEM capacity at a minority-serving institution serving students from over 65 countries.

Abstract

In this project, funded by the MPS-leaps (launching early-career academic pathways) program and managed by the division of chemistry, professor mullane and her students at hawaii pacific university will perform studies focused on the development of novel separation methods for rare earth elements and early transition metals. Rare earth elements play a vital role in modern technologies, such as permanent magnets in wind turbines, leds, and in rechargeable batteries. However, the united states remains heavily dependent on imports, with 80% of its rare earth element supply coming from china. Recycling of decommissioned materials can help to decrease reliance on importing rare earth elements for use in these technologies. Professor mullane and her students will develop novel separation methods utilizing selective photochemical reactions in combination with conventional separation techniques, such as crystallization and extraction. Their studies could contribute a low-energy and effective method for separating metals with similar atomic radii and oxidation states and expand on the active research in the photoredox chemistry of rare earth elements and early transition metals. Beyond its scientific and industrial merit, this research will be conducted by undergraduate students at hawaii pacific university where the students will receive training in air sensitive synthesis techniques, electrochemistry, and characterization techniques. In this work, professor mullane and her students will synthesize novel and known light-absorbing complexes of lanthanides and early transition metals to determine how the ligand-metal interactions influence the absorption and emission of light by collecting and analyzing the excitation and emission of related complexes. Additionally, she and her students will screen the synthesized complexes as potential photocatalysts with organic substrates and exploit differences in photochemical reactivity for use in metal separations. Undergraduate students working on this project will gain experience with spectroscopic techniques such as NMR, IR, UV/VIS, and fluorescence spectroscopy, and cyclic voltammetry as they characterize the complexes and interrogate the reasons for any observed differences in their excitation and emission spectra by computational and experimental techniques. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are not planned for this award.