Sol–gel preparation of spherical γ-Al2O3 with macro-mesopores as an efficient adsorbent for acid fuchsin

Spherical gamma-alumina (γ-Al2O3) has a wide range of applications in the field of adsorption due to its low bulk density, larger pore size, higher strength and thermal stability. In this study, spherical γ-Al2O3 with macro-mesopores was prepared with isopropanol aluminium as the aluminium source via a sol–gel process. Spherical γ-Al2O3 was characterised by means of nitrogen adsorption and desorption curve, scanning electron microscope, transmission electron microscope, X-ray diffraction and so on. The adsorption performance of the prepared spherical γ-Al2O3 was studied by probe experiment of adsorption of acid fuchsin (AF) solution. The results showed that the spherical γ-Al2O3, which was prepared under the condition of hydrolysis time of 1 h, hydrolysis temperature of 85°C, ageing temperature of 95°C and ageing time of 7 h, had the strongest adsorption capacity for AF, and the adsorption efficiency could reach 96.24% in 40 mg/l AF solution. In addition, after six cycles of use, the spherical γ-Al2O3 had no damage and the adsorption efficiency still could reach 88.40%. This work provides a feasible method for the preparation of spherical γ-Al2O3, and could also help to understand the connection between its textural properties and adsorption performance.