LAUSR

The conversion of gibbsite to boehmite via hydrothermal treatment at 200°С in 1.5 wt % HCl is studied by X-ray powder diffraction, IR spectroscopy, Brunauer–Emmett–Teller analysis, scanning (SEM) and transmission (TEM) electron microscopy. The steps of the process are identified. Gibbsite is split in an acidic medium, with its specific surface area increasing up to 150 m2/g, into thin lamellas that have a disordered boehmite structure. Needle-shaped boehmite crystals are formed from thin elongated lamellas of diverse sizes due to the oriented overlaying and cross-linking with the elimination of weakly bound water and structural perfection.