Production of SBA-15 mesoporous silica containing ammonium groups in the surface layer

Abstract

The template method (surfactant: Pluronic 123) has been applied to produce mesoporous silica that contain ammonium groups [≡Si(CH2)3NH3]+, [≡Si(CH2)3NH2(CH2)2NH3]2+, [≡Si(CH2)3NH2(CH2)2NH2(CH2)2NH3]3+ and [≡Si(CH2)3N(CH3)3]+ in the surface layer, which has been confirmed both by data of elemental analysis for nitrogen and by IR spectroscopy. Using diffractometry and TEM, it has been demonstrated that the synthesized samples contain a hexagonal structure characteristic of SBA-15 silica. This agrees with the parameters of their porous structure calculated by isotherms of low-temperature adsorption of nitrogen: S sp = 520–750 m2/g, V c = 0.6–1.2 cm3/g, and d = 4.9–8.9 nm.