Preparation of Silica Nanoparticles and its Beneficial Role in Cementitious Materials

Abstract

Spherical silica nanoparticles (n-SiO2) with controllable size have been synthesized using tetraethoxysilane as starting material and ethanol as solvent by sol-gel method. Morphology and size of the particles was controlled through surfactants. Sorbitan monolaurate, sorbitain monopalmitate and sorbitain monostearate produced silica nanoparticles of varying sizes (80-150 nm), indicating the effect of chain length of the surfactant. Increase in chain length of non-ionic surfactant resulted in decreasing particle size of silica nanoparticles. Further, the size of silica particles was also controlled using NH3 as base catalyst. These silica nanoparticles were incorporated into cement paste and their role in accelerating the cementitious reactions was investigated. Addition of silica nanoparticles into cement paste improved the microstructure of the paste and calcium leaching is significantly reduced as n-SiO2 reacts with calcium hydroxide and form additional calciumsilicate-hydrate (C-S-H) gel. It was found that calcium hydroxide content in silica nanoparticles incorporated cement paste reduced ~89% at 1 day and up to ~60% at 28 days of hydration process. Synthesized silica particles and cement paste samples were characterized using scanning electron microscopy (SEM), powder X-ray diffraction (XRD), infrared spectroscopy (IR) and thermogravimetric analysis (TGA).

Preparation and Characterization of CaSO4–SiO2–CaO/SO42- Composite for Biodiesel Production

“…There are some separated cavities due to the CO 2 departure during CaO preparation from the limestone [34]. For SiO 2 as shown in Figure (5b), the particles are defined and their shapes are irregular [24]. Figure (5c) shows the SEM of the composite CaSo 4 -CaO-SiO 2 /SO 4 2-catalyst of 1:1 SiO 2 to CaO weight ratio.…”

“…The bands at 674 and 597 cm -1 represents the Ca-O bonds [31,32] these bands appear stronger and sharper by increasing the CaO weight ratio. On the other hand, the IR band at 1120 is related to SiO 2 [24] that appear strongly in the high SiO 2 weight ratio. The IR peaks in the region of 380-400 cm -1 are associated with Si-O-Si bending vibration [33].…”

Effect of NiO and Light Intensity on Dielectric Constant of SiO2-B2O3-Bi2O3-Na2CO3 Glass Based on Silica Gel of Natural Sands

“…The addition oxide such as B2O3 [8]. add optical properties of glass, B 2 O 3 [9], and Na 2 CO 3 are mostly to reduce the melting point as well as to improve the optical or dielectric properties of the glass.…”

Production of Nano Silica Using Sol Gel Method by Varying the Concentration of Surfactant and to Study Its Behaviour in Blended Material

“…The goal of this study is to investigate the possibilities of using Alf 3 production waste, washed in ammonia solution, in cement stone specimens. Chemically treated silica gel additive was proved to reduce the amount of Ca(OH) 2 and CaCO 3 in hardened cement paste samples. Experimental research has revealed that the density in hydrated samples reduces from 2220 kg/m 3 to 2030 kg/m 3 with the increase of silica gel content from 0% to 35%.…”

“…Have done extensive work on preparation of silica nano particles ranging from few hundred nanometres to several micrometres by control hydrolysis of TEOS in ethanol. Preparation of silina nano particles and its beneficial role in cementitious material is documented in research papers [2,3] spherical silica nano particles (n-sio 2 ) with controllable size have been synthesized using tetra ethoxysilane as a starting material and ethanol as solvent by sol gel method. Increase in chain length of surfactant and solvent resulted in decreasing particle size of silica nanoparticles.…”