<abstract xml:lang="en" xmlns="http://www.w3.org/1999/xhtml">Reaction of δ-Na2Si2O5 and α-Na2Si2O5 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-Na2Si2O5 and α-Na2Si2O5 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-Na2Si2O5 and α-Na2Si2O5 possess, respectively, the platy and the needle-like morphology. Hydrated α-Na2Si2O5 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-Na2Si2O5 is more strongly bound than that in kanemite.</abstract>

Reaction of δ-Na2Si2O5 and α-Na2Si2O5 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-Na2Si2O5 and α-Na2Si2O5 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-Na2Si2O5 and α-Na2Si2O5 possess, respectively, the platy and the needle-like morphology. Hydrated α-Na2Si2O5 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-Na2Si2O5 is more strongly bound than that in kanemite.

Layered Sodium Disilicates as Precursors of Mesoporous Silicas. Part II: Hydration of δ-Na2Si2O5 and α-Na2Si2O5

Polish Academy of Sciences, Institute of Catalysis and Surface Chemistry, ul. Niezapominajek 8, 30-239 Kraków, Poland

Faculty of Geology, Geophysics and Environmental Protection, AGH-University of Science and Technology, al. Mickiewicza 30, 30--059 Kraków, Poland

Mineralogia

Layered Sodium Disilicates as Precursors of Mesoporous Silicas. Part II: Hydration of δ-NaSiO and α-NaSiO

Reaction of δ-Na2Si2O5 and α-Na2Si2O5 with water at ambient conditions has been studied. The first substrate produced kanemite, the other a crystalline solid,...

Layered Sodium Disilicates as Precursors of Mesoporous Silicas. Part II: Hydration of δ-Na₂Si₂O₅ and α-Na₂Si₂O₅

Online veröffentlicht: 21. Nov. 2008

Seitenbereich: 161 - 170

DOI: https://doi.org/10.2478/v10002-007-0024-7

Schlüsselwörter
NaSiO, layered silicates, kanemite, hydration

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