A team of UIC physics researchers from Professor Mark Schlossman’s lab have published research in Proceedings of the National Academy of Sciences of the United States of America(PNAS),a leading science journal. Department of Physics undergraduates David Walwark, Jeffrey Harvey, and Glenn Hanlon co-authored the paper, along with Department of Physics graduate students Zhu Liang and Cem Erol. Researchers from the University of Chicago, the University of California, Santa Cruz, and the UIC Department of Chemical Engineering also contributed to the paper.
The paper, “Nanoscale view of assisted ion transport across the liquid-liquid interface,” was featured in the March 2018 issue of the journal. It examines how metal ions behave during a process known as solvent extraction, which targets certain ions for extraction using an organic solvent. The process has wide-ranging applications from mining to nuclear waste remediation, but its exact mechanics are poorly understood. The research team, investigated how certain types of ions behave during the extraction process. They found that the ions form an unconventional, yet stable structure at the interface between the liquid solvent and an ion-charged solution.
The researchers have discovered a transition state of the ion transfer process, shedding light on the moment at which the ions targeted for extraction have made the leap into the solvent, but have not yet dispersed. A model introduced to support the experiments describes a dynamical process that distorts the interface and facilitates ion transport across it. These findings could lead to refinements that make the process more efficient and effective—and that means better strategies for cleaning up environmental hazard sites.
Image courtesy Mark Schlossman. The illustration shows the domain budding mechanism. (A) A flat region of bare interface (dodecane above, water below) becomes (B) spontaneously curved due to the adsorption of extractants and their interactions with ions (not shown) at the interface. (C) The reduction in length of the domain edge (dashed line) reduces the line tension energy, which balances the bending energy required to form a spherical reverse micelle. (D) Separation of the micelle from the interface extracts the ions (not shown) in the interior of the reverse micelle into the bulk organic phase.
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