A pure silica BEA type zeolite (Si-β) was hydrothermally synthesized in a system of SiO_2-TEAOH-HF-H_2O without stirring. Tetraethylammonium hydroxide (TEAOH) was used as the structure directing agent and tetraethylorthosilicate (TEOS) with reagent grade was used as the silica source. β zeolite with a low Si/Al ratio (Si/Al = 20) was dealuminated by reaction with nitric acid solution (13 mol/L) at reflux temperature. The calcined Si-β and dealuminated β zeolite were characterized with XRD, FT-IR, ~(29)Si MAS NMR and adsorption isotherms. The comparison of Si-β with a dealuminated zeolite β has proved that the Si-β possesses a perfect [Si-O] framework and porous structure, and exhibits high hydrophobic/organophilic properties.

Key words: SILICON, ZEOLITE, STRUCTURE CHARACTERISTICS, HYDROPHOBILITY, XRD, NMR, IR