Lanthanide binding peptide surfactants at air-aqueous interfaces for interfacial separation of rare earth elements

• 成果类型: Article
• 署名作者: Macias, Luis E. Ortuno; Jimenez-Angeles, Felipe; Marmorstein, Jason G.; Wang, Yiming; Crane, Stephen A.; Surabh, K. T.; Sun, Pan; Sapkota, Bikash; Hummingbird, Eshe; Jung, Woojin; Qiao, Baofu; Lee, Daeyeon; Dmochowski, Ivan J.; Messinger, Robert J.; Schlossman, Mark L.; Nunez, Cesar de la Fuente; Radhakrishnan, Ravi; Petersson, E. James; de la Cruz, Monica Olvera; Bu, Wei; Bera, Mrinal; Lin, Binhua; Tu, Raymond S.; Stebe, Kathleen J.; Maldarelli, Charles
• 署名单位: City University of New York (CUNY) System; City College of New York (CUNY); Northwestern University; University of Pennsylvania; University of Pennsylvania; University of Illinois System; University of Illinois Chicago; University of Illinois Chicago Hospital; University of Chicago
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9027
• DOI: 10.1073/pnas.2411763121
• 发表日期: 2024-12-24
• 关键词: liquid interfaces; solvent-extraction; foam flotation; high-affinity; proteins; adsorption; calcium; complexes; chemistry; RECOVERY

摘要

Rare earth elements (REEs) are critical materials to modern technologies. They are obtained by selective separation from mining feedstocks consisting of mixtures of their trivalent cation. We are developing an all-aqueous, bioinspired, interfacial separation using peptides as amphiphilic molecular extractants. Lanthanide binding tags (LBTs) are amphiphilic peptide sequences based on the EF-hand metal binding loops of calcium-binding proteins which complex selectively REEs. We study LBTs optimized for coordination to Tb3+ using luminescence spectroscopy, surface tensiometry, Xray reflectivity, and X-ray fluorescence near total reflection, and find that these LBTs capture Tb3+ in bulk and adsorb the complex to the interface. Molecular dynamics show that the binding pocket remains intact upon adsorption. We find that, if the net negative charge on the peptide results in a negatively charged complex, excess cations are recruited to the interface by nonselective Coulombic interactions that compromise selective REE capture. If, however, the net negative charge on the peptide is -3, resulting in a neutral complex, a 1:1 surface ratio of cation to peptide is achieved. Surface adsorption of the neutral peptide complexes from an equimolar mixture of Tb3+ and La3+ demonstrates a switchable platform dictated by bulk and interfacial effects. The adsorption layer becomes enriched in the favored Tb3+ when the bulk peptide is saturated, but selective to La3+ for undersaturation due to a higher surface activity of the La3+ complex.