Optimization of textural properties and surface chemistry of MCM-41 mesoporous silicas

Abstract

The synthesis of mesoporous silicas requires the removal of the template through calcination or extraction with solvents. This stage influences the concentration and accessibility of the silanol groups arranged on the surface. In this work, the influence of different template removal methodologies on the superficial textural and chemical properties of MCM-41 was studied. Mesoporous silicas were obtained from two silicon sources: TEOS and an industrial sodium silicate solution. The structuring agent was removed using ethanol as extraction solvent or applying thermal treatments. The materials were characterized by SAXS, SEM, HRTEM, FTIR and N₂ adsorption/desorption. The industrial sodium silicate promoted the obtaining of solids with superior textural characteristics and greater pore order. On the other hand, the removal methods with ethanol were more efficient to preserve the silanol groups on the surface.