Synthesis of Nano-α-Al2O3 for 99Mo Adsorbent

Abstract

The fission-product ⁹⁹Mo, having a high specific activity, is commonly used in alumina-based ⁹⁹Mo^/99mTc generator. Due to the limitation on the use of fission-product ⁹⁹Mo, an alternative route for ⁹⁹Mo production, namely activation of natural molybdenum using thermal neutron, has been explored. Unfortunately, this neutron-activated ⁹⁹Mo has a low specific activity. Therefore, ⁹⁹Mo^/99mTc generator based on neutron-activated ⁹⁹Mo requires a column with higher capacity absorbent. Thus, in this study, the nanomaterial of alumina (nano-a-Al₂O₃) was synthesized which was expected to have a higher ⁹⁹Mo adsorption capacity, so that nano-a-Al₂O₃ could be potentially used as a matrix of column for ⁹⁹Mo/^99mTc generator based on neutron-activated ⁹⁹Mo. Nano-a-Al₂O₃ was synthesized by using sol-gel method and characterized using FTIR spectroscopy, X-ray diffraction (XRD), and transmission electron microscopy (TEM). In addition, the Scherrer method was used to determine the size of the crystals. To determine the ⁹⁹Mo adsorption capacity of the synthesized nanoalumina, the nano-a-alumina was soaked in nitric acid solution for one hour at room temperature followed by removing the filtrate. Then, the nano-a-alumina was soaked in ⁹⁹Mo solution (Na₂⁹⁹MoO₄) at certain conditions. The FTIR spectra for nano-a-alumina showed adsorption peak at 450-500 cm^-1 which indicated the presence of Al-O bond. The XRD patterns of nanoalumina crystals showed peaks at 2θ region of 25.8°, 35.9°, 38°, 52.8°, and 57.7°, indicating that the synthesized alumina had an α-phase with an average crystal size of ~5.5 nm. The average ⁹⁹Mo adsorption capacity of the synthesized alumina was 47.55 ± 12.3 mg Mo/g nano-a-Al₂O₃.