High-purity nano silica powder from rice husk using a simple chemical method

Figures & data

Figure 1. EDS pattern of nano silica powder (a) 0.5 N, (b) 1 N, (c) 1.5 N, (d) 2 N and (e) 2.5 N NaOH purification treatments.

Figure 2. FTIR spectrum of nano silica powder (a) 2 N and (b) 2.5 N NaOH purification treatments.

Figure 3. (Colour online) Raman spectra of nano silica powder (a) 2 N NaOH purification treatment, (b) and (c) 2.5 N NaOH purification treatment sintered at 973 and 1373 K, respectively.

Table 1. Characteristic comparison of the prepared nano silica with conventional nano silica.

Nano silica product	Purity (%)	Average particle size (nm)	Surface area (m^2g^−1)
19	95	60	235
20	–	50–70	–
21	99	33–46	260
22	95	26	250
Present study	99.98	∼ 25	274

Figure 4. XRD pattern of pure nano silica powder (a) sintered at 973 K and (b) sintered at 1373 K.

Figure 5. TEM image of pure nano silica powder.

Figure 6. Particle size distribution of pure nano silica powder.

Figure 7. BET surface area plot of nano silica powder.

Liou , T H . 2004 . Preparation and characterization of nano-structured silica from rice husk . Mater. Sci. Eng.: A , 364 : 313 – 323 .

 Web of Science ®Google Scholar

Zaky , R R , Hessien , M M and El-Midany , A A . 2008 . Preparation of silica nanoparticles from semi-burned rice straw ash . Powder Technol. , 185 : 31 – 35 .

 Web of Science ®Google Scholar

Real , C , Alcala , M D and Criado , J M . 1996 . Preparation of silica from rice husks . J. Am. Ceram. Soc. , 79 : 2012 – 2016 .

 Web of Science ®Google Scholar

Conradt , R , Pimkhaokham , P and Leela-Adison , U . 1992 . Nano-structured silica from rice husk . J. Non-Cryst. Solids , 145 : 75 – 79 .

 Web of Science ®Google Scholar