Preparation of fibrous γ-alumina with large pore volume via co-current dropwise addition method
【Abstract】A co-current dropwise addition method was employed to prepare γ-alumina with a large pore volume with sodium aluminate (NaAlO2) and aluminum sulfate [Al2(SO4)3] used as starting materials. The effects of the reaction pH during the precipitation process, starting material concentration, aging pH and adding surfactant sodium dodecylbenzenesulfonate (SDBS) were investigated. It was found that the starting material concentration could affect the nucleation-growth process and result in different morphologies, such as irregular sheets, fibers or granules, in which fibers could form the largest pore volume. When the NaAlO2 concentration was 0.5–0.75 mol/L, the reaction pH was controlled at 8–9.5 and the aging pH was controlled at about 9, the obtained γ-alumina was fibrous. Besides, adding SDBS during the aging process could further improve the pore volume and pore diameter distribution. The method successfully prepared fibrous γ-alumina with a pore volume of 1.35–2.19 mL/g, a specific surface area of 300–500 m2/g and an average pore diameter of 14–21 nm, a fiber length of 50–60 nm and diameter about 5 nm. It can provide a good catalyst carrier for the residue hydrogenation process.
【Keywords】 NaAlO2-Al2(SO4)3; precipitation method; γ-alumina; co-current dropwise addition; nucleation–growth; surfactant;
(Translated by REN XF)
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