A didecylamine modified porous silica-polymer based adsorbent for the efficient separation of 99Mo and 99mTc

99m Tc, one of the most vital radioisotopes in nuclear medicine, is primarily supplied by molybdenum‑technetium ( 99 Mo/ 99m Tc) generators using alumina as the adsorbent. Nevertheless, this conventional technology poses challenges including the adsorbent's low Mo adsorption capacity, low distribution coefficient, and potential radioactive leakage. To address this challenge, a novel silica-based amine adsorbent (DDA/SiO 2 -P) was developed for the high adsorption capacity of Mo and efficiently separation of Mo and Tc. Given their similar chemical properties, rhenium (Re) was employed as a non-radioactive surrogate for technetium in this study. The adsorbent demonstrates exceptional performance with a Mo adsorption capacity of 119 mg/g, 170 mg/g, and 222 mg/g at 288 K, 308 K, and 318 K at pH = 2 respectively, achieving a remarkable separation factor ( SF Mo/Re ) of 3200. Furthermore, the adsorbent enables efficient elution of Re using 0.9 wt% NaCl solution. In a dynamic column experiment simulating generator operation, the recovery rate of Re reached 85.15% in the first ten collected fractions with the chemical purity of Re 99%, corresponding to a radiochemical purity of 99.9%. Additionally, the synthesis method for this adsorbent is straightforward and cost-effective, positioning it as a promising candidate for next-generation 99 Mo/ 99m Tc generators.