Layered Sodium Disilicates as Precursors of Mesoporous Silicas. Part II: Hydration of [delta]-Na2Si2O5 and [alpha]-Na2Si2O5

• Published in: Mineralogia 2007-07, Vol.38 (2), p.161
• Main Authors: Michalik-Zym, Alicja, Zimowska, Malgorzata, Bielanska, Elzbieta, Bahranowski, Krzysztof, Serwicka, Ewa
• Format: Article
• Language: English
• ISSN: 1899-8291; 1899-8526
• DOI: 10.2478/v10002-007-0024-7

Layered Sodium Disilicates as Precursors of Mesoporous Silicas. Part II: Hydration of δ-Na[2]Si[2]O[5] and α-Na[2]Si[2]O[5] Reaction of δ-Na[2]Si[2]O[5] and α-Na[2]Si[2]O[5] with water at ambient conditions has been studied. The first substrate produced kanemite, the other a crystalline solid, assumed to be the layered hydrated α phase of yet unknown structure. Important differences have been observed in the kinetics of δ-Na[2]Si[2]O[5] and α-Na[2]Si[2]O[5] reactions with water, the phase transformation of the latter being distinctly slower. The observed different rates of hydration were associated with the different structural properties of the disilicates investigated. Hydrated δ-Na[2]Si[2]O[5] and α-Na[2]Si[2]O[5] possess, respectively, the platy and the needle-like morphology. Hydrated α-Na[2]Si[2]O[5] contains less interlayer water, which is considered the reason for basal spacing being lower than that of kanemite. The interlayer water trapped between the layers of hydrated α-Na[2]Si[2]O[5] is more strongly bound than that in kanemite.