Synthesis and characterization of silica nanoparticles from clay

Abstract

We report a method to synthesize silica nanoparticles from bentonite clay. A series of thermal and acid treatment processes was performed on bentonite clay to lower the alumina and increase the silica content. The obtained silica rich clay was treated in two different concentrations (10 wt% and 40 wt%) with sodium hydroxide solution to form sodium silicate solutions (SSS). One type of SSS was hydrolyzed with three different concentrations (5 M, 10 M and 15 M) of nitric acid in the presence of ethanol as cosolvent while the other SSS was hydrolyzed with nitric acid in the presence of three different quantities (10 ml, 20 ml and 30 ml) of ethanol as cosolvent. A range of silica particle sizes from nanometer to micrometer was obtained by varying the contents of silica rich clay, HNO 3 , and ethanol. It was observed that the concentration of silica rich clay and HNO 3 had a direct effect on the particle size. The increase in the quantity of ethanol from 10 ml to 20 ml produced bimodal particles of nanometer and micrometer size, which maintained at 30 ml. Inductively coupled plasma optical emission spectroscopy, atomic absorption spectroscopy, X-ray fluorescence, scanning electron microscopy and X-ray diffraction were utilized to characterize the clay, SSS and nanoparticles.

Efficient adsorptive extraction materials by surface protein‐imprinted polymer over silica gel for selective recognition/separation of human serum albumin from urine

“…According to XRD spectra, the formation of polymer on the silica surface, plot the intensity of calculated counts versus position of 2θ° (Figure ). As can be seen, broad peaks of silica bands (22 ± 1°) suggest that the silica particles are at an amorphous state . The intensity of silica particles (SiO 2 ) at 22° is lower than the silica modified particles (TMSP‐SiO 2 ) due to the reduction of the size of the silica particles from microparticles to submicro particles .…”

“…As can be seen, broad peaks of silica bands (22 AE 1 ) suggest that the silica particles are at an amorphous state. 40 The intensity of silica particles (SiO 2 ) at 22 is lower than the silica modified particles (TMSP-SiO 2 ) due to the reduction of the size of the silica particles from microparticles to submicro particles. 40 After polymerization, the intensity at 22 was attributed to silica band for MIP, which was decreased when compared with the silica modified particles, suggesting the formation of the polymer.…”

“…40 The intensity of silica particles (SiO 2 ) at 22 is lower than the silica modified particles (TMSP-SiO 2 ) due to the reduction of the size of the silica particles from microparticles to submicro particles. 40 After polymerization, the intensity at 22 was attributed to silica band for MIP, which was decreased when compared with the silica modified particles, suggesting the formation of the polymer. 41 The XRD intensity of NIP is a little higher compared with the MIP, indicating the higher thickness of imprinted polymer than the NIP (Figure 3).…”

Synthesis of Nanosilica via Olivine Mineral Carbonation under High Pressure in an Autoclave

“…It is therefore likely that increasing amounts of nickel will be produced from laterites. Since laterite type ores naturally occur close to the surface, economical open pit mining techniques are employed to recover the ore after removal of the overburden [3]. The laterite ore consists of fresh saprolite such as K 0.4 (Si 3.0 Al 1.0 ) 4.0 (Al 2.0 Mg 0.3 ) 2.33 O 10 (OH) 2 and nontronite such as Na 0,3 (Fe 3+ ) 2 (Si,Al) 4 O 10 (OH) 2 •nH 2 O.…”

“…Stopic et al [14] have shown the reaction path of direct forsterite carbonation in the aqueous solution without any deeper consideration of the formed silica particles as shown Equations (1)- (3) and Figure 1.…”