Investigation of the Structure‐Directing Effect of Surfactants on the Distribution of Silicate Species Using ²⁹Si‐NMR Spectroscopy

Abstract

Silicate anions were studied using 29 Si NMR to investigate the structure-directing effect of a surfactant (sodium dodecylsulfate-SDS) on the distribution of silicate species present in alkaline silicate solutions. The distribution of the anions in the presence of polyelectrolytes was also investigated by 29 Si NMR through the use of different bases including tetramethyl ammonium hydroxide (TMAOH) and sodium hydroxide (NaOH). Both SDS and the polyelectrolytic solutions were shown to stabilize low molecular weight silicate species and thus inhibit polymerization.

27Al NMR study of the effect of aqueous and methanolic media on the distribution of tetraphenylammonium aluminosilicate species

“…In principle, NMR spectroscopy is powerful tool for detecting and characterizing aluminum and silicon containing species in aqueous solution. Accordingly, a number of investigations have been carried out to address the structure of ions present in silicate, aluminate and aluminosilicate solutions [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. Kinrade and Swaddle identified 29 Si NMR peaks due to low molecular weight aluminosilicate anions of sodium aluminate solutions by 29 Si NMR spectroscopy [18].…”

“…The notation Q n for silicate solutions, where n refers to the number of siloxane bridges, is well established [10][11][12][13][14][15]. In the case of individual aluminum sites in aluminosilicate anions there is a special similar notation.…”