Abstract: Ordered hexagonal mesoporous silica (HMS) and Al-containing hexagonal silica (AlSBA) are prepared directly from sepiolite using leaching and sequent template synthesis. The structure, surface acidity, and specific surface area of mesoporous materials are investigated by means of SAXRD, TPD, and BET adsorption methods. Mesoporous materials with features of HMS are prepared after the sepiolite is treated by 5 mol•L^-1 HCl acid solution and then kept in NaOH solution at 120 ℃ for 72 h. The ordered organization of materials improves with the formation of the AlSBA framework when modified-sepiolite is treated with NaAlO2 solution. Specific surface areas of HMS and AlSBA are 508 m2•g^-1 and 946 m2•g^-1, and the pore sizes are 3.4 nm and 3.9 nm, respectively. NH3-TPD results show that two acid centers appear on AlSBA and HMS surfaces, and the acidity and acid strength of acid centers in AlSBA are stronger than that of corresponding acidic centers in the HMS mesoporous materials.

Key words: Sepiolite, Mesoporous molecular sieves, Acidic leaching, Template synthesis, Surface acidity