Influence Of The Type Of Sepiolite On The Modification Of The Pore-size Distribution In γ-al_2o_3 Supports

摘要

γ-Al_2O_3 modified supports with bimodal pore-size distributions were prepared by the addition of different types of natural sepiolites (α or β) into alumina. The supports were characterized by nitrogen physisorption, mercury porosimetry, X-ray diffraction, HRTEM and DTA techniques. A wide range of S_(BET) (94-238 m~2 g~(-1)), pore volumes (0.3-0.82 cm~3 g~(-1)), and pore sizes were obtained in the supports depending on the type of sepiolite and its concentration added into alumina. The pore sizes were distributed as follows: mesopores around 1.8 nm in radius, mesopores in the radius range 3.0-25 nm and macropores between 25 and 300 ran in radius. The shape of the pore-size distributions depended on the type of sepiolite: the modal peak for pores larger than 3.0 nm was broad with β-type sepiolites and narrow with α-type sepiolites. The mesopore and macropore sizes can be controlled by the type of sepiolite as well as its concentration added to alumina.