Biomolecule-Assisted Synthesis of Hierarchical Multilayered Boehmite and Alumina Nanosheets for Enhanced Molybdenum Absorption.

In this work, we demonstrate the effective utilization of various biomolecules for creating a series of mesoporous boehmite (γ-AlOOH) and gamma-alumina (γ-Al2O3) nanosheets with unique hierarchical multi- layered structures via a facile mixed hydrothermal-solvothermal method. The nature and concentration of the biomolecules strongly influence the degree of crystallinity, morphology and/or textural properties of the resulting γ-AlOOH and γ-Al2O3 nanosheets, allowing for their easy tuning. The hierarchical γ-AlOOH and γ-Al2O3 multilayered nanosheets synthesized using biomolecules are found to exhibit enhanced crystallinity, improved particle separation and well-defined multilayered structures compared to those obtained without biomolecules. More impressively, these γ-AlOOH and γ-Al2O3 nanosheets possess high surface areas of up to 425 and 371 m2 g-1, respectively, due to their mesoporous nature and unique hierarchical multilayered structure. When employed for molybdenum (Mo) adsorption toward medical radioisotope production, the hierarchical γ-Al2O3 multilayered nanosheets exhibit Mo adsorption capacities of 33.1-40.6 mg g-1. The Mo adsorption performance was identified to be influenced by the synergistic combination of crystallinity, surface area, and pore volume. It is expected that the proposed biomolecule-assisted strategy may be expanded for the creation of other 3D mesoporous oxides in the future.