11/07/2023
By Mark Tries

The Radiological Sciences Program invites you to attend a thesis defense by M.S. candidate Ridhita Borhan on: “Exploring Radiation Effects on Extraction Chromatographic Materials.”

Date: Nov. 14, 2023
Time: 12:30 – 2:30 p.m.
Location: Olsen Hall, Room 114
This will be a hybrid thesis defense, both in-person and online via Zoom. Those interested in attending online should contact Ridhita Borhan and committee member Mark Tries at least 24 hours prior to the thesis defense to request access to the meeting.


Committee Chair: Erin Bertelsen, Ph.D., Assistant Professor, Physics and Applied Physics

Committee Members:

  • Marian Jandel, Ph.D., Assistant Professor, Physics and Applied Physics
  • Mark Tries, Ph.D., Associate Professor, Physics and Applied Physics

Abstract:
The recovery of target nuclides from radioactive waste streams provides an avenue for increasing the inventory of valuable radionuclides for industrial use. Extraction chromatography, a subset of liquid–liquid chromatography, is a separation technique in which an extractant is physically adsorbed on a porous solid support that may offer high-purity separation. Extraction chromatography support materials used for the separation of valuable radionuclides must be able to withstand the high radiation environments of the radioactive waste stream matrix. In this work, four chromatographic supports: diatomaceous earth, carbon-coated diatomaceous earth, Vulcan XC-72R, and Amberlite XAD7 were functionalized with bis-(2-ethylhexyl) phosphoric acid (HDEHP) and examined for their radiation stability in air and in contact with an aqueous phase. The materials were evaluated by changes in europium partitioning and compared to a solvent extraction system using bis-(2-ethylhexyl) phosphoric acid in n-dodecane. The chromatographic supports and solvent extraction system were exposed to a Co-60 gamma ray source at increasing absorbed doses. Using scanning electron microscopy (SEM), changes in the morphology of the support materials were examined before and after irradiation. The solvent extraction system showed the most significant change in europium uptake with increasing radiation dose, whereas minimal changes in europium uptake were observed for the extraction chromatography support materials. The europium distribution profiles indicate that the chromatographic support materials hold up well in a radiation environment up to 2,500 kGy.

All interested persons are welcome to attend.