Spherical boehmite particles with hollow interiors were synthesized in the hydrothermal condition using aluminum nitrate as Al3+ source, urea as precipitator and citric acid as structure directing agent, which was further transformed to hollow γ-Al2O3 products after simply heating post-treatment under 700 °C for 4 h. The crystal phase, morphologies and microstructure of the sample were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), respectively. It is suggested that the as-synthesized boehmite powder possesses hollow interior with ca.1 μm in diameter and shells with 100 nm in thickness, and the calcinated sample have γ crystal phase without morphological changes after heat post-treatment. The interesting hollow structure evolution was further investigated by comparative experiments and a reasonable evolution mechanism was proposed, in which the chelation of citric acid with Al3+ species and the dissolution of boehmite play the critical role in forming the hollow structure of boehmite.

Antibacterial MgO-Triclosan nanocomposites was prepared by a facile adsorption process using nano-MgO as adsorbent in a triclosan ethanol solution. Adsorption experiments showed that as-synthesized MgO nanoparticles possess high adsorptive capability towards triclosan. TG and FTIR analysis showed that the MgO-Triclosan nanocomposites performed good thermotolerance. Antibacterial tests showed that it still retained most of its active component, and exhibits high antimicrobial activity even after heat treatment for 30 min at 250 °C.