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. 2013 Feb 6;8(1):58.
doi: 10.1186/1556-276X-8-58.

Synthesis of silica nanoparticles from Vietnamese rice husk by sol-gel method

Van Hai Le  1 , Chi Nhan Ha Thuc, Huy Ha Thuc
Affiliations

Synthesis of silica nanoparticles from Vietnamese rice husk by sol-gel method

Van Hai Le et al. Nanoscale Res Lett. .

Abstract

Silica powder at nanoscale was obtained by heat treatment of Vietnamese rice husk following the sol-gel method. The rice husk ash (RHA) is synthesized using rice husk which was thermally treated at optimal condition at 600°C for 4 h. The silica from RHA was extracted using sodium hydroxide solution to produce a sodium silicate solution and then precipitated by adding H2SO4 at pH = 4 in the mixture of water/butanol with cationic presence. In order to identify the optimal condition for producing the homogenous silica nanoparticles, the effects of surfactant surface coverage, aging temperature, and aging time were investigated. By analysis of X-ray diffraction, scanning electron microscopy, and transmission electron microscopy, the silica product obtained was amorphous and the uniformity of the nanosized sample was observed at an average size of 3 nm, and the BET result showed that the highest specific surface of the sample was about 340 m2/g. The results obtained in the mentioned method prove that the rice husk from agricultural wastes can be used for the production of silica nanoparticles.

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Figures

Figure 1
Figure 1
SEM micrographs of silica nanoparticles obtained from surface-active substances. CA (a), Arkopal (b), and PEG (c).
Figure 2
Figure 2
TEM micrographs of silica nanoparticles obtained from surface-active substances. CAC (a), ABDAC (b), Aliquat 336 (c), CTAB (d), and CPB (e).
Figure 3
Figure 3
TEM micrographs of silica nanoparticles obtained from CTAB. 0.5 (a), 1.0 (b), 1.5 (c), 2.0 (d), 2.5 (e), and 3.0 wt.% (f).
Figure 4
Figure 4
Silica nanoparticles dispersed in water/butanol.
Figure 5
Figure 5
TEM micrographs of silica nanoparticles obtained at different aging temperatures. 30°C (a), 45°C (b), 60°C (c), and 80°C (d).
Figure 6
Figure 6
TEM micrograph of silica nanoparticles obtained at aging time 0 h.
Figure 7
Figure 7
TEM micrographs of silica nanoparticles obtained at different aging times. 3 (a), 5 (b), 6 (c), 7 (d), 8 (e), and 12 h (f).
Figure 8
Figure 8
FT-IR spectra of the nanoparticles.
Figure 9
Figure 9
XRD diagram of silica nanoparticle.
See this image and copyright information in PMC

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