Preparation And Characterization Of Ultrafine γ-Al₂O₃ And Its Application In Hydrolysis Of COS

Deposition method and sol-gel method were employed to prepare ultrafine γ-Al₂O₃. The influence of preparation methods and conditions was investigated. Prepared ultrafine γ-Al₂O₃ was used in hydrolysis of COS and the new process for one-stepped removal of COS was established.Deposition method was used to prepare ultrafine γ-Al₂O₃, which was characterized by XRD, TEM and specific surface area analysis. The influence of preparation conditions, such as reaction temperature, proportions between reactants, concentrations of reactant solution, pH value of intermixture and aging time, on product's properties including crystal structure, microcosmic appearance and particle size was investigated. When reaction temperature is 40℃, pH value of intermixture is around 8.0, and aging time is above 12 hours, the microcosmic appearance of product is spindle-shaped congeries formed of amounts of weeny particles. This congeries have single figure, which length is almost 200nm and width is about 100nm.Sol-gel method was used to prepare nano-sized γ-Al₂O₃, which was characterized by XRD, TEM and specific surface area analysis. The influence of preparation conditions, such as reaction temperature, H₂O quantity, calcination temperature and HNO₃ quantity, on sol's performance and product's properties including crystal structure, microcosmic appearance and particle size was investigated. When reaction temperature is 75℃, H₂O: AIP (mol)=100, HNO₃: AIP (mol)=0.03, and calcination temperature is 600℃, the microcosmic appearance of product is well-separated and fibre-shaped.The addition of γ-Al₂O₃ as hydrolytic catalyst to ethanol-amine industrial desulfurizer couldtransfer COS, which removal was more or less difficult, to H2S through hydrolysis, so that a new process for one-stepped removal of COS was established. The influence of preparation methods and conditions on catalytic activity was investigated. The catalytic activity of Y-AI2O3 prepared by sol-gel method was higher than that of Y-AI2O3 prepared by deposition method.