New Method of Preparing Activated Silica Sols

Henry, Clarence R.

doi:10.1002/j.1551-8833.1958.tb15551.x

Cited by 1 publication

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References 11 publications

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“…One type of nano-silica solution is prepared from a reaction between a diluted sodium silicate solution and a mineral acid, such as sulfuric acid. This type of nano-silica solution had been used for water treatment and is called “activated silica sols” . Commercially available silica gels and precipitated silicas are usually produced from the reaction of the same kinds of solutions.…”

Section: Introductionmentioning

confidence: 99%

Micropore to Macropore Structure-Designed Silicas with Regulated Condensation of Silicic Acid Nanoparticles

et al. 2005

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A new preparation method for porous silica particles was developed using activated silica sols which are called nano-silica solutions in this paper. Several kinds of organic and inorganic acids are employed to neutralize diluted sodium silicate solutions to form the nano-silica solutions: formic acid, acetic acid, propionic acid, oxalic acid, succinic acid, dl-malic acid, citric acid, and tricarballylic acid as carboxylic acids, and sulfuric acid and hydrochloric acid as inorganic acids. The effect of salts in the nano-silica solution is also studied. The products were investigated using a field emission scanning electron microscope, an X-ray diffractometer, the nitrogen adsorption technique, and a mercury porosimeter. Microporous silicas were produced when carboxylic acids were applied; the formation of micropores was influenced by the pH of the nano-silica solutions and molecular sizes of the carboxylic acids. Addition of a salt in a citric acid solution increased the mesopore volume. Macropores were formed when inorganic acids including salts were applied; the salt nanoparticles which were crystallized in silica spheres acted as templates. The anion types and salt concentrations in the nano-silica solutions affected the aggregation condition of silica nanoparticles, following the Schulze-Hardy rule.

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Section: Introductionmentioning

confidence: 99%