Practicality of hierarchically macro/mesoporous γ-Al2O3 as a promising sorbent in the preparation of low specific activity 99Mo/99mTc generator

Highlights: • HMMA showed high absorption capacity to Mo ions. • LSA ⁹⁹Mo/^99mTc generator used HMMA as column materials has been prepared. • ^99mTc eluted from ⁹⁹Mo/^99mTc generator were used for preparation of radiopharmaceuticals using MDP and MIBI. Hierarchically macro-/mesoporous γ-Al₂O₃ (HMMA) was synthesized and characterized by various analytical techniques. The results indicated that HMMA possessed macropores (∼0.45 μm) and mesopores (∼10.6 nm) with a large surface area (∼542 m² g⁻¹). The absorption behaviors of Mo and Re with HMMA were investigated. The maximum static absorption capacity could reach about 250 mg Mo per g HMMA. The absorption equilibrium can be attained quickly within 10 mins. At initial Mo ions concertation of 10,000 mg L⁻¹, the breakthrough capacity was determined to be around 200 mg Mo per g HMMA. Additional, absorption mechanism results indicated that Mo ions reacts strongly with a hydroxyl on the surface of γ-Al₂O₃ and an adjacent Al atom, simultaneously. A 9.15 mCi (339 MBq) ⁹⁹Mo generator was prepared and evaluated its performance for over one week. The recovery of ^99mTc could reach about 89% with favorable radionuclidic, radiochemical and chemical purity for nuclear medicine application. HMMA has a potential application prospect for the preparation of low specific activity (LSA) ⁹⁹Mo/^99mTc generator.