| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 73359 | Microporous and Mesoporous Materials | 2013 | 8 Pages |
•The dissolution of olivine produces an amorphous porous nano-silica of high quality.•The sulfates can be removed from the micropores by washing and filtration.•Silicas with purities above 99% have a SSABET of 350 m2/g and SSAMP of 150 m2/g.•Ostwald ripening treatment reduces the SSABET by 75% and the SSAMP by 95%.•Ostwald ripening can be used to tailor the SSA of olivine nano-silica.
The production of porous amorphous nano-silica by the olivine route is an interesting alternative to the existing commercial production methods because of the much lower energy requirements of this process. The produced olivine nano-silica has a specific surface area between 100 and 400 m2/g and primary particles between 10 and 25 nm (agglomerated in clusters). The process conditions of the dissolution of olivine and the subsequent ripening treatment influence the specific surface area of the nano-silica in the following ways. (1) The cleaner the nano-silica is, the higher the specific surface area is. Thus, high-purity silicas presents an SSA between 300 and 400 m2/g. (2) The higher the filtration pressure is, the higher the surface area will be. (3) The ripening treatment can diminish the specific surface of nano-silica by three quarters and reduce the microporous surface area by 90%. A 99% pure nano-silica with specific surface area controlled between 90 and 400 m2/g can be synthesized by ripening treatment in an alkaline solution at room temperature. Therefore, tailored olivine nano-silica can provide additional environmental and economic benefits over the current commercial products.
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