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Controlling the Intermediate Structure of an Ionic Liquid for f‑Block Element Separations
journal contribution
posted on 2017-04-19, 00:00 authored by Carter W. Abney, Changwoo Do, Huimin Luo, Joshua Wright, Lilin He, Sheng DaiRecent research has
revealed molecular structure beyond the inner
coordination sphere is essential in defining the performance of separation
processes; nevertheless, such structure remains largely unexplored.
Here we apply small-angle neutron scattering (SANS) and X-ray absorption
fine structure (XAFS) spectroscopy to investigate the structure of
an ionic liquid system studied for f-block element separations. SANS
data reveal dramatic changes in the ionic liquid microstructure (∼150
Å) which we demonstrate can be controlled by judicious selection
of counterion. Mesoscale structural features (>500 Å) are
also
observed as a function of metal concentration. XAFS analysis supports
formation of extended aggregate structures, similar to those observed
in traditional solvent extraction processes, and suggests additional
parallels may be drawn from further study. Achieving precise tunability
over the intermediate features is an important development in controlling
mesoscale structure and realizing advanced new forms of soft matter.