Room Temperature Synthesis of Boehmite and Crystallization of Nanoparticles: Effect of Concentration and Ultrasound

In the present work, boehmite naoparticles with the size of 15-30 nm have been synthesized on addition of NaOH to the solution of Al(NO3)(3)center dot 9H(2)O as the source of aluminum. FTIR, SEM and TEM have been employed for characterization of samples. Bayerite formed by mixing the starting materials at room temperature which was immediately transformed to boehmite at that temperature. Crystallization of boehmite nanoparticles was achieved by imposing hydrothermal conditions. The size of boehmite particles obtained was strongly dependent on the concentration of Al-containing solution and also the OH/Al ratio. Among the various synthesis conditions employed, the best reaction route at room temperature was obtained. Agglomerates of the size 900 mu m formed in some of the synthesis methods, the size of which was decreased to about 50 mu m on concentration variations. Agglomeration mechanism and effect of ultrasonic mixing on the particle size has also been reported.