Spray-dried mesoporous silica spheres functionalized with carboxylic groups

Spherical mesoporous particles functionalized with carboxylic groups were prepared through a co-condensation route by spraying a solution containing hydrolyzed alkoxide (tetraethoxysilane) and an organosilane (4-(triethoxysilyl) butyronitrile)), in the presence of nonionic block copolymer as template. Samples have been then treated with sulfuric acid to remove the template and to hydrolyze simultaneously the -CN to -COOH groups. The mesoporous spheres show high specific surface area and narrow pore size distribution. TG and FT-IR analysis confirm the incorporation of the carboxylic moieties, whose amount results ca 1 meq g−1 by titration with alkali solution. The mean size of mesoporous spheres can be ranged from few microns to submicron by varying the initial precursor concentration of spray-dried synthesis solution.