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Volume 3, Issue 2
Insights in Analytical Electrochemistry
ISSN: 2470-9867
Analytical Chemistry-Formulation 2017
August 28-30, 2017
Page 61
8
th
Annual Congress on
&
14
th
International Conference and Exhibition on
August 28-30, 2017 Brussels, Belgium
Analytical and Bioanalytical Techniques
Pharmaceutical Formulations
Chromatographic separation of calcium isotopes by using crown ether resin and acidic solutions
Yasuhiko Fujii
1
, Shin Okumura
1
, Saori Umehara
2
, Masao Nomura
1
, Toshitaka Kaneshiki
1
and
Tadafumi Kishimoto
2
1
National University in Tokyo, Japan
2
Osaka University, Japan
N
atural calcium consists of six isotopes. The heaviest isotope
48
Ca is a double-beta-decay nuclide and important for the
study of neutrinoless double-beta decay. Since the natural abundance of
48
Ca is very low (0.187%), the enrichment of
48
Ca
on a large scale is anticipated. However, the enrichment is very difficult, since calcium has no appropriate gaseous compounds
which are usable as mediums for isotope separation processes such as gaseous diffusion, centrifugation, etc. Therefore, we have
studied the chemical isotope separation based on the isotopic fractionation between chemical compounds in solution phase and
in adsorption phase. The enrichment of calcium isotopes was observed at the adsorption band boundary of chromatography
using benzo-18-crown-6 ether resin. For this purpose, the crown ether resin was synthesized by condensation polymerization of
crown ether monomer and organic materials in porous silica beads. In our previous work calcium isotope separation by crown
ether resin has been studied by using concentrated HCl solutions, mixed medium of alcohol and acid and organic solvents, etc.
In the present work, attention was placed on the engineering aspects of the chromatographic separation system. Prior to the
chromatographic isotope separation experiments, adsorption experiments were conducted in batch wise to obtain information
on the adsorption of calcium in benzo-18-crown-6-ether resin (B18C6) at different conditions of HBr concentration. Then
calcium isotope enrichment experiments were conducted by breakthrough-mode column chromatography using aqueous
HBr feed solutions and B18C6 resin. Observed separation coefficients were 3.9x10-3 ~ 4.3x10-3. Determined engineering
parameter HETP (Height Equivalent to a Theoretical Plate) were 2.6 ~ 6.7 mm; the HETP clearly showed the dependence on
the concentration of calcium in feed solution. Discussion was extended to the analysis on the productivity of the separation
system using the concept of separative power. Results indicate that the separative power is approximately proportional to the
stage velocity. This fact suggests that the increase in the band speed is an effective measure to increase the capability of the
separation system. A conceptual design of
48
Ca enrichment plant is presented as a summary of the basic research work on the
chromatographic calcium isotope separation.
Biography
Academic Degrees received from Tokyo Institute of Technology; Master of Engineering in 1969 and Doctor of Engineering in 1973. Occupational Career: Chemical
Engineer for Asahi Chem. Co. (1972 - 1974), Research Staff of Tokyo Institute of Technology (Research Associate, Associate Professor and Professor) (1974 -
2009), Professor Emeritus in2009. Published papers are 185. Award of Atomic Energy Society of Japan in 2003, Award of Japan Association of Ion Exchange in
2004 and Fellow of American Association for the Advancement of Science in 2006.
fujiiyaxyz@road.ocn.ne.jpYasuhiko Fujii et al., Insights in Analytical Electrochemistry, 3:2
DOI: 10.21767/2470-9867-C1-002