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Precipitated silica
About: Precipitated silica is a research topic. Over the lifetime, 1401 publications have been published within this topic receiving 20992 citations.
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TL;DR: In this paper, the selective oxidation of hydrogen sulfide to elemental sulfur, using a commercial, precipitated silica promoted ferric oxide based catalyst, was investigated in laboratory and pilot-plant reactors.
Abstract: The selective oxidation of hydrogen sulfide to elemental sulfur, using a commercial, precipitated silica promoted ferric oxide based catalyst, was investigated in laboratory and pilot-plant reactors. Low levels of hydrogen sulfide (1-3 vol%) can be readily removed, but a continuous slow decrease in catalyst activity was apparent. X-ray photoelectron spectroscopy showed that the loss of activity was due to the formation of ferrous sulfate, which is known to be less active than the ferric oxide. In addition, studies using a model feed showed that the propene and HCN impurities in the plant feed stocks also act as potent catalyst poisons.
23 citations
Patent•
16 Mar 1984
TL;DR: The relationship between the relatively narrow ranges of precipitated silica and hydrogen bonding surfactants is critical and responsible for the favorable viscosity, ability to suspend abrasives, and minimal or lack of syneresis.
Abstract: A thixotropic cleaner comprising about 6 to 12% of a precipitated silica; about 0.05 to 2.5% of a cationic, nonionic or zwitterionic or amphoteric surfactant, or mixtures thereof, that has the ability to hydrogen bond and mixtures thereof; an acid; and an abrasive. The relationship between the relatively narrow ranges of precipitated silica and hydrogen bonding surfactant is critical and responsible for the favorable viscosity, ability to suspend abrasives, and minimal or lack of syneresis. All of these advantageous characteristics are stable over an extended period of time.
23 citations
TL;DR: In this paper, a physicochemical analysis was performed on silicas precipitated in an emulsion system, where the organic phase consisted of cyclohexane and non-ionic emulsifiers.
23 citations
TL;DR: In this paper, structural characteristics of Fe{sup 3+} oxide/silica co-precipitates were investigated and several previously undetermined key insights were gained into the structure of iron oxide and silica coprecimitates through this examination.
Abstract: Structural characteristics of Fe{sup 3+} oxide/silica co-precipitates were investigated. The association between these materials is relevant to practically all natural aqueous systems due to the prevalence of iron and silicon in the Earth's crust. Crystallographic information is very difficult to obtain from these precipitates due to the nanocrystalline nature of ferrihydrite and the amorphous structure of precipitated silica. Several previously undetermined key insights were gained into the structure of iron oxide/silica co-precipitates through this examination. The distribution of iron and silicon throughout co-precipitate particles is illustrated along with the influence of their association. Evidence to the governing factor behind differences in apparent crystallinity is also presented. This information culminates in the formulation of a precipitation pathway, displaying the formation of the co-precipitates.
22 citations
Patent•
24 Apr 1970
TL;DR: A finely divided organically modified silica is formed by adding an inorganic acid at an elevated temperature to an aqueous alkali methyl silicate solution in contact with a water-soluble reactive organic polymer which is present in an amount of from about 3 to about 24 percent by weight relative to the weight of the thus precipitated silica.
Abstract: A finely divided organically modified silica is formed by adding an inorganic acid at an elevated temperature to an aqueous alkali methyl silicate solution in contact with a water-soluble reactive organic polymer which is present in an amount of from about 3 to about 24 percent by weight relative to the weight of the thus precipitated silica.
22 citations