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NIRE Annual Report
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1997

Preparation of Porous Materials Using Layered Compounds

Siliceous Materials Division
Materials Processing Department
Objectives
Porous materials have attracted considerable attention for their uses as sorbents or catalysts. Special interest is given in the synthesis, characterization and application of the porous materials with well defined pores. In our laboratory, from the viewpoint of advanced utilization of mineral ores and development of new materials, we have tried to prepare such valuable porous materials.
Results
Microporous materials obtained from antigorite by acid treatment
Acid leaching of antigorite (Mg3 Si2O5(OH)4) resulted in the formation of microporous materials(Fig.1). The pores with sizes of around 1- 2nm were created upon Mg2+ dissolution from the framework of antigorite. The maximum specific surface area and pore volume of the solid containing 2% MgO are about 400m2/g and 0.22ml/g, respectively. Further, by total dissolution of Mg2+ from antigorite, an amorphous silica(>99.3% SiO2) can be prepared. Both the porous products and amorphous silica could be used as functional matrials because of the molecular sieving effect for aromatics, or effectiveness for preparation of many kinds of siliceous materials.


Si-pillared materials prepared by intercalation of Layered polysilicate
A new siliceous porous material with high BET surface area, 1152m2/g with calcination at 600°C and 586m2/g even at 900ºC, was obtained by intercalation of octylamine and TEOS into H-ilerite(Table 1). The silica-pillared products, with around 1nm distance(2t) between the pillars and 2.5nm gallery height, may have the best thermal stability and the highest adsorption volume(V) of all silica-pillared compounds prepared from other layered materials. The above porous material and also, the products derived from H-magadiite and H-kenyaite, are expected to be used as a new functional material where zeolite is not effective as a catalyst or molecular sieve.

Selected Publications
1) Micropore formation by acid treatment of antigorite. Chemistry of Materials, 7:2241- 2246,1995
2) New Silica-Pillared Material Prepared from the Layered Silicic Acid of Ilerite. J.Chem.soc.,Chem.Commun.,1995:2427-28,1995
3) Dispersion of H-magadiite and H-kenyaite Particles by Ion Exchange of H+ with Alkali Ions. Langmuir,12:1124-1126,1996

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