Molybdenum Adsorption Properties of Alumina-Embedded Mesoporous Silica for Medical Radioisotope Production

Abstract

In this work, we have prepared alumina-embedded mesoporous silica and investigated their molybdenum (Mo) adsorption properties. To synthesize such materials, mesoporous silica particles were firstly synthesized via a soft-templated approach followed by the introduction of aluminium butoxide into the mesopores, which was converted into alumina by heat treatment at high temperatures. The obtained alumina-embedded mesoporous silica samples (Alx-MPS) were characterized by low- and wide-angle X-ray diffractions, nitrogen adsorption-desorption isotherms, and transmission electron microscopy. The effects of Al/Si ratios and calcination temperature on their Mo adsorption properties were also carefully investigated by using the batch method. The experimental results showed the following trend in Mo adsorption capacity in relation to the calcination temperature: 750 °C > 600 °C > 900 °C > 1050 °C and Al/Si molar ratio: Al0.1-MPS < Al0.3-MPS < Al0.5-MPS < Al0.6-MPS.

Biomolecule‐Assisted Synthesis of Hierarchical Multilayered Boehmite and Alumina Nanosheets for Enhanced Molybdenum Adsorption

“…The Mo adsorptione xperimentsw ere performed at an optimum pH of 3b ased on our previous findings. [62,63] TheM oa dsorption properties of these three samples are provided in Table 4. Amonga ll tested samples, AlEG-Pro(1)-700 shows the highest Mo adsorption capacityo f4 0.8 mg (Mo) g À1 (sample), followed by AlEG-Ala(1)-700 (37.1 mg g À1 )a nd AlEG-Ala(1.5)-700 (33.1 mg g À1 ).…”

“…These three samples were selected due to their outstanding textural properties and uniform multilayered structures. The Mo adsorption experiments were performed at an optimum pH of 3 based on our previous findings . The Mo adsorption properties of these three samples are provided in Table .…”

“…The Mo adsorption capacities of these three samples exceed the limit of 2–20 mg (Mo) per g (sample) previously reported for commercial Al 2 O 3 used in 99 Mo/ 99m Tc generators . Furthermore, they also show a superior performance for Mo adsorption compared to previously reported mesoporous γ‐Al 2 O 3 and Al‐doped mesoporous SiO 2 …”

“…[51] Furthermore,t hey also show as uperior performance for Mo adsorption comparedt op reviously reported mesoporous g-Al 2 O 3 [62] and Al-doped mesoporous SiO 2 . [63] The trend in the Mo adsorption capacity matches well with the trend in the pore volume:1 .30 cm 3 g À1 (40.8 mg g À1 ) > 1.16 cm 3 g À1 (37.1 mg g À1 ) > 0.95 cm 3 g À1 (33.1 mg g À1 ). This implies that ah igher pore volume is beneficial for enhancing the Mo adsorption capacity due to the availability of more sites for the adsorption of Mo anions.…”

Nanoarchitectonic‐Based Material Platforms for Environmental and Bioprocessing Applications

“…Enhancing the surface area and pore volume through nanoarchitecture‐based design of aluminum materials into mesoporous alumina with changing preparative conditions such as varying calcination temperatures, resulted in increased adsorption of Mo (41.6 mg g −1 ) compared to that of e commercial alumina powder (34.9 mg g −1 ) . Increased Mo adsorption was also observed for alumina‐embedded mesoporous silica, which was prepared through the introduction of aluminum butoxide into silica mesopores and subsequent conversion to alumina at high temperatures . The presence of Lewis acid sites within the optimized mesoporous structures could enhance the adsorption of Mo species.…”