Dissolution of Molybdenum in Hydrogen Peroxide: A Thermodynamic, Kinetic and Microscopic Study of a Green Process for 99mTc Production

Abstract

99mTc-based radiopharmaceuticals are the most commonly used medical radioactive tracers in nuclear medicine for diagnostic imaging. Due to the expected global shortage of 99Mo, the parent radionuclide from which 99mTc is produced, new production methods should be developed. The SORGENTINA-RF (SRF) project aims at developing a prototypical medium-intensity D-T 14-MeV fusion neutron source specifically designed for production of medical radioisotopes with a focus on 99Mo. The scope of this work was to develop an efficient, cost-effective and green procedure for dissolution of solid molybdenum in hydrogen peroxide solutions compatible for 99mTc production via the SRF neutron source. The dissolution process was extensively studied for two different target geometries: pellets and powder. The first showed better characteristics and properties for the dissolution procedure, and up to 100 g of pellets were successfully dissolved in 250–280 min. The dissolution mechanism on the pellets was investigated by means of scanning electron microscopy and energy-dispersive X-ray spectroscopy. After the procedure, sodium molybdate crystals were characterized via X-ray diffraction, Raman and infrared spectroscopy and the high purity of the compound was established by means of inductively coupled plasma mass spectroscopy. The study confirmed the feasibility of the procedure for production of 99mTc in SRF as it is very cost-effective, with minimal consumption of peroxide and controlled low temperature.

Preparation and Characterization of Isostructural Na2MoO4 and Na2WO4 and a Study of the Composition of Their Mixed System

“…Experimental observations have shown that molybdenum is more reactive than tungsten, i.e., with the same mass, volume of peroxide and other conditions, the former dissolves completely faster than the latter and, in both cases, the reaction initially is slow for a short induction time, which depends on the temperature. However, once the reaction starts, it proceeds rapidly with a large development of heat (they are highly exothermic) and the formation of a large quantity of bubbles, mainly oxygen [34]. This is possibly due to the fact that the surfaces of metallic pieces are covered by a very thin layer of oxide with intermediate valence, such as MoO 2 , and that it acts as a passivation layer.…”

“…Molybdenum and tungsten have many similar chemical properties, including their reactivity with respect to concentrated H 2 O 2 solutions [ 34 ]. This also suggests that a solid solution can form.…”

Characterization and Formation Mechanism of Ag2MoO4 Crystals via Precipitation Method: Influence of Experimental Parameters and Crystal Morphology

“…Crystals of Ag 2 MoO 4 were prepared by the precipitation route by mixing liquid solution of AgNO 3 (Carlo Erba Reagents, Milano, Italy, purity 99.8%) and Na 2 MoO 4 under different conditions. In turn, Na 2 MoO 4 was prepared from metallic Mo (Luoyang Combat Tungsten & Molybdenum Material Co., Ltd. (Luoyang, China), purity = 99.9%) by reaction with H 2 O 2 35% (Carlo Erba Reagents), according to [14,15]. Solid Molybdenum reacts quickly with hydrogen peroxide, leading to a clear solution of molybdic acid (H 2 MoO 4 ).…”

Mechanical Behaviour of the Rotating Target SORGENTINA-RF

“…The general description of the project and the main activities can be found in further detail in [3] while a set of specific studies is presented in [4][5][6][7][8][9][10].…”