Influence of synthesis parameters on the properties of nanostructured γ-Alumina using plackett-burman experimental design

Abstract

Mesoporous nanostructured γ-Al₂O₃ powders were synthesized through multi- step precipitation procedures using the pH-swing technique. Structural and morphological characteristics in addition to the thermal behavior of the procured samples were characterized via X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fourier transform infrared (FT-IR) spectroscopy, thermogravimetry-derivative thermal gravimetric       (TG-DTG) and N₂ adsorptionâdesorption isotherm. Plackett-Burman design was implemented as a screening method to examine the impacts of fifteen variables on physical properties of synthesized γ-Al₂O₃ as a response variable. Specific surface area, pore volume and average pore diameter of the prepared samples were found to be within the ranges of 72-335.7 m²/g, 0.26-1.03 cm²/g and 4.6-15.2 nm, respectively. It was determined that the variables including pH value on the acidic region, time in the alkaline region and number of pH-swing frequencies had major effects on the pore diameter of the procured γ-Al₂O₃ powders. Calcination by steaming had the most significant effect on specific surface area, while the pH value on the acidic region had the greatest impact on pore volume.