Study of the effect of Mg(II) addition and the annealing conditions on the structure of mesoporous aluminum oxide using Plackett–Burman design

Abstract

A statistical design was used to investigate the effect of various processing conditions on the structure of sol–gel derived Mg(II) doped alumina. Six process variables were selected based on the Plackett–Burman design: concentration of magnesium nitrate, time and temperature of alcohol evaporation, temperature and time of annealing and heating rate were changed at two levels. For every set of conditions, samples with different specific surface area and degree of crystallinity were obtained. Analysis of the results showed that the annealing temperature, heating rate and concentration of magnesium nitrate were the main factors affecting the average crystallite size of the predominant alumina phase. In the case of the specific surface area, two of selected six variables had pronounced effects; however, the temperature of annealing was more effective than others. The present results showed that the proposed model that uses crystallite size as a response variable is preferable to other research.