The effect of polyoxyethylene (40) stearate surfactant on novel synthesis of mesoporous γ-alumina from Kano kaolin

Mesoporous γ-alumina was synthesized by acid extraction of alumina from Kano kaolin using polyoxyethylene (40) stearate (PS) as a surfactant. The synthesized alumina was characterized using X-ray diffraction (XRD), N2 adsorption–desorption, Fourier transform infra-red spectroscopy (FTIR), field emission scanning electron microscopy attached with energy-dispersive X-ray (FESEM–EDX), and thermogravimetric analysis (TG–DTA). High-purity mesoporous γ-Al2O3 with relatively large surface area and narrow pore size distribution was obtained. For comparison the preparation in the absence of surfactant was also carried out. In this study mesoporous alumina was also obtained even in the absence of the surfactant, however, the addition of PS resulted in modification on physical properties and morphology. The surface area increased from 169.0 m2/g to 222.7 m2/g, pore size from 4.4 nm to 5.6 nm and pore volume from 0.32 cm3/g to 0.45 cm3/g. Crystallite size was also found to increase from 2.68 nm to 3.33 nm after the addition of the surfactant.