Presentation Title

Octamethylcyclotetrasiloxane Interaction with Lithium Ions

Faculty Mentor

Dr. Kimberley Cousins and Dr. Robert Pellenbarg

Start Date

17-11-2018 12:30 PM

End Date

17-11-2018 2:30 PM

Location

CREVELING 72

Session

POSTER 2

Type of Presentation

Poster

Subject Area

physical_mathematical_sciences

Abstract

Lithium, for batteries, is in demand globally. Lithium recovery usually relies on brines. The brine – based extraction could be improved by using octamethylcyclotetrasiloxane (D-4). D-4 is a crown ether analog containing silicon atoms.  The molecule  is  a  partial  negatively charged ring  able to bond to positively  charged  metal ions (e.g.Li+).  Specifically, we  report that Li+ ‘fits’ in the D-4 ring, and  that D-4 extraction could recover lithium from brines, the Salton Sea  or the ocean. Our main focus is on examining D-4 sequestration of Li+ at different concentrations (1M LiCl in deionized water and  at decadal concentrations  below that).  D-4 sequestering of Li+ was confirmed by NMR and AA Emission Flame test.  D-4 Si-29 NMR signals at  35.56, 6.02, -18.50, -34.87 and -84.89  ppm  were used find the differences in concentration trends. AA flame test was to find out the  difference in concentration of aqueous Li+  ions  between before and after D-4  interaction. D-4 interacting with Li+ at higher concentrations of LiCl in deionized water presented a greater difference  in  Si-29 NMR  chemical  shifts  than lower concentrations. When using AA  emission  test  of aqueous solutions, higher concentrations of Li+were tested first before adding D-4. After interaction with D-4, the counts did not reveal a significant change. This result may be related to the fact that lithium has a very strong emission profile.  At lower Li+ concentrations, there was a marked difference in counts of pre- and post- interaction with D-4.

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Nov 17th, 12:30 PM Nov 17th, 2:30 PM

Octamethylcyclotetrasiloxane Interaction with Lithium Ions

CREVELING 72

Lithium, for batteries, is in demand globally. Lithium recovery usually relies on brines. The brine – based extraction could be improved by using octamethylcyclotetrasiloxane (D-4). D-4 is a crown ether analog containing silicon atoms.  The molecule  is  a  partial  negatively charged ring  able to bond to positively  charged  metal ions (e.g.Li+).  Specifically, we  report that Li+ ‘fits’ in the D-4 ring, and  that D-4 extraction could recover lithium from brines, the Salton Sea  or the ocean. Our main focus is on examining D-4 sequestration of Li+ at different concentrations (1M LiCl in deionized water and  at decadal concentrations  below that).  D-4 sequestering of Li+ was confirmed by NMR and AA Emission Flame test.  D-4 Si-29 NMR signals at  35.56, 6.02, -18.50, -34.87 and -84.89  ppm  were used find the differences in concentration trends. AA flame test was to find out the  difference in concentration of aqueous Li+  ions  between before and after D-4  interaction. D-4 interacting with Li+ at higher concentrations of LiCl in deionized water presented a greater difference  in  Si-29 NMR  chemical  shifts  than lower concentrations. When using AA  emission  test  of aqueous solutions, higher concentrations of Li+were tested first before adding D-4. After interaction with D-4, the counts did not reveal a significant change. This result may be related to the fact that lithium has a very strong emission profile.  At lower Li+ concentrations, there was a marked difference in counts of pre- and post- interaction with D-4.