Physicochemical Properties of Mesoporous Silicas Modified with Hydrazide and Amide Functional Groups

Resumo

Physicochemical properties of mesoporous silicas modified with hydrazide and amide functional groups were studied. It was found that the main properties of the sorbents under study, characterized by pK_a1, are weakly pronounced. The replacement of the counter ion with a hydroxide occurs in a less alkaline medium, compared with monomer analogs. The sorbent modified with N', N'-dimethylhydrazide groups by the impregnation method has pK_a2 = 11.78, which is indicative of a sufficient strength of bonding between the counter ion and the silica matrix. The temperature limits, heat effects, and decomposition stages of the sorbents were determined.