Precipitation of amorphous SiO2 particles and their properties

Abstract

-The experimental conditions were optimized for the synthesis of amorphous SiO 2 particles by the reaction of neutralization of sodium silicate solution with H 2 SO 4 solution. Amorphous SiO 2 particles were characterized by XRD, FT-IR, FE-SEM, EDS and microelectrophoresis. The amorphous peak was located at 2θ = 21.8 o in the XRD pattern. Primary SiO 2 particles were ~ 15 to ~ 30 nm in size and they aggregated into bigger particles. Amorphous SiO 2 particles showed a specific surface area up to 130 m 2 g -1, dependent on the parameters of the precipitation process. The EDS spectrum of amorphous SiO 2 particles did not show contamination with sulfate or other ions, which cannot be excluded in traces. pH zpc =1.7 was obtained by microelectrophoresis.

Effect of Thermal Treatment on Textural Properties of Natural Montmorillonite

“…In addition, diatomite from the Ankara region of Turkey was investigated for the effect of heating on the surface area and on its porosity. The study was performed on three diatomite forms; as received, under different temperature calcinations and after Moreover, no considerable change in the surface areas for samples treated with hot hydrochloric acid and followed by calcination were observed at different temperatures between 700 and 1150 °C [17].…”

Adsorption of CO2 on silica dioxide catalyst impregnated with various alkylamine

“…The IR band at 975 cm -1 is due to silanol groups and ~800 cm -1 can be assigned to Si-O-Si symmetric stretching vibrations. IR spectrum for precipitated SiO 2 showed IR band at 3437 cm -1 and 1632 cm -1 which were assigned to the stretching vibration of and bending vibration of H 2 O molecules [29]. Referring to the FTIR spectrum of pure SiO 2 in FIGURE 1 (ii) and 1 (iii), the broad band at range 3500-3100 cm -1 and ~1640 cm -1 are represent to the stretching vibration and bending vibration of H 2 O molecules with very low intensities due to the calcinations step of SiO 2 before impregnation process.…”

Composites of Fe3O4/SiO2from Natural Material Synthesized by Co-Precipitation Method

“…This peak intensity will increase along with the addition of silica, where the position of polymer form is very influential in the composite [15]. The higher the variation of silicate addition into Fe 3 O 4 the more declined the diffraction peak pattern of Fe 3 O 4 [11, 16,17]. …”