One-step preparation of high-purity boehmite by the effect of sugar alcohol in the aluminum-water reaction

In this study, adding sugar alcohols to the aluminum-water reaction enables the one-step boehmite synthesis with energy savings and cost reduction. The obtained boehmite formed as stacked layers of embroidery, with particle size decreasing as the sugar alcohol concentration increased. The boehmite obtained in the sugar alcohol system possesses a substantial number of pores, a higher density of active sites, and a lower proportion of AlO6 coordination bonds, exhibiting a specific surface area beyond 100 m2 g−1, greater than the boehmite obtained through the hydrothermal method (3.46 m2 g−1). This study proposes that sugar alcohols undergo a complexation reaction on the aluminum surface, directly forming aluminum oxo complexes (boehmite) without generating an intermediate. Subsequently, boehmite crystal growth preferentially along the (120), (031), and (200) crystal faces. This low-energy and non-polluting method for preparing high-purity (>99.99 %) boehmite with high activity holds significant potential for applications in adsorbents, carriers, and high-performance alumina materials. •One-step synthesis of boehmite in the aluminum-water reaction.•The obtained boehmite (>99.99 %) has a surface area greater than 100 m2 g−1.•Sugar alcohols promote the complexation reaction on aluminum surfaces.•The boehmite exhibits excellent adsorption and flame-retardant properties.•A low-energy and non-polluting method for preparing boehmite.