Recovery Profiles of Molybdate Solutions Through Varying DowexTM-1 Resin Amounts, and Translation to Mo99/Tc99m Separation

Jared Fitzpatrick,Kennedy Mang'Era

doi:10.5539/apr.v7n1p72

Abstract

The influence of molybdenum concentration and resin amount on the retention of molybdenum in 5M NaOH on DowexTM-1 columns with successive elutions of saline and tetrabutylammonium bromide (TBAB) was investigated. Studies were performed with 45, 75, 125, 175, or 250 mg of resin and at 100 and 250 mg/mL molybdenum concentrations. Initial pass-through molybdenum recoveries from the column were 97.8% at 100 mg/L and 97.8% at 250 mg/mL (n=3 at each resin amount). Molybdenum breakthrough into TBAB solvent was low for all five resin amounts. Values for the 100mg/mL solution were 0.33 – 3.73 ppm, representing 0.0002 - 0.0014% of the original molybdenum load; and were 0.96 - 11.27 ppm for the 250 mg/mL solution, equivalent to 0.0002 – 0.0027%. Breakthrough into TBAB is generally higher with higher resin amounts for both the 100 mg/ml and 250 mg/mL molybdenum concentrations. The resin can be used for high molybdenum loads, with care taken to optimize the relative resin-solute amounts.

Highlights

We and collaborators are developing linear accelerator technology for a viable long-term production alternative for the current ageing medical isotope reactor production of molybdenum-99 (Mo99), and in line with the global transition to technologies that are more environmentally sustainable (Canadian Light Source, 2012; International Atomic Energy Agency, 2013; Kobes et al, 2010; Mang’era et al, 2011; Natural Resources Canada, 2012; Prairie Isotope Production Enterprise, 2010; Uvarov et al, 1998)
As the target material for accelerator production is an isotope of molybdenum and the conversion, the radioactive product Mo99 product is intrinsically of low-to-medium specific activity, and the high relative molybdenum chemical loads mean that the traditional alumina column used separation of the daughter radionuclide technetium-99m (Tc99m) from Mo99 is not viable
Solvent-solvent extraction and solid-phase affinity chromatography are two techniques that have been applied to successfully separate technetium-99m (Tc99m) and molybdenum-99m (Mo99) from stocks of low-specific activity Mo99 of the type that is obtained by linear accelerator production (International Atomic Energy Agency, 1995; Kanpp & Mirzadeh, 1994)

Summary

Introduction

We and collaborators are developing linear accelerator technology for a viable long-term production alternative for the current ageing medical isotope reactor production of molybdenum-99 (Mo99), and in line with the global transition to technologies that are more environmentally sustainable (Canadian Light Source, 2012; International Atomic Energy Agency, 2013; Kobes et al, 2010; Mang’era et al, 2011; Natural Resources Canada, 2012; Prairie Isotope Production Enterprise, 2010; Uvarov et al, 1998). As the target material for accelerator production is an isotope of molybdenum and the conversion, the radioactive product Mo99 product is intrinsically of low-to-medium specific activity, and the high relative molybdenum chemical loads mean that the traditional alumina column used separation of the daughter radionuclide technetium-99m (Tc99m) from Mo99 is not viable. Solvent-solvent extraction and solid-phase affinity chromatography (including use of DowexTM-1 resin) are two techniques that have been applied to successfully separate technetium-99m (Tc99m) and molybdenum-99m (Mo99) from stocks of low-specific activity Mo99 of the type that is obtained by linear accelerator production (International Atomic Energy Agency, 1995; Kanpp & Mirzadeh, 1994). The Tc99m is subsequently recovered, usually with the solvent tetrabutyl ammonium bromide (TBAB), and it is critical for clinical use that minimal Mo99 breakthrough into the TBAB eluate is seen

Methods

Results

Conclusion