METHOD OF PREPARING CERIUM DIOXIDE NANOPARTICLES
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Abstract
A method of making cerium dioxide nanoparticles includes: a) providing an aqueous reaction mixture having a source of cerous ion, a source of hydroxide ion, a nanoparticle stabilizer, and an oxidant at an initial temperature no higher than about 20° C.; b) mechanically shearing the mixture and causing it to pass through a perforated screen, thereby forming a suspension of cerium hydroxide nanoparticles; and c) raising the initial temperature to achieve oxidation of cerous ion to eerie ion and thereby form cerium dioxide nanoparticles having a mean diameter in the range of about 1 nm to about 15 nm. The cerium dioxide nanoparticles may be formed in a continuous process.
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Citations
119 Claims
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1. (canceled)
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93. A process for making cerium dioxide nanoparticles comprising the steps of:
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providing an aqueous reaction mixture comprising a source of cerous ion, a source of hydroxide ion, a nanoparticle stabilizer comprising an ethoxylated carboxylic acid, or salt thereof, wherein the molar ratio of nanoparticle stabilizer to total metal ions is greater than 0.2, and an oxidant at an initial temperature in the range of about 20°
C. to about 100°
C.; andproviding temperature conditions effective to enable oxidation of cerous ion to ceric ion, thereby forming a product dispersion comprising cerium dioxide nanoparticles. - View Dependent Claims (94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 118, 119)
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108. A process for forming a homogeneous mixture containing cerium dioxide nanoparticles, at least one nanoparticle stabilizer, a surfactant, water, and a nonpolar solvent, said process comprising the steps of:
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a) providing an aqueous mixture including stabilized cerium dioxide nanoparticles produced by close association of said nanoparticle stabilizer with said cerium dioxide nanoparticles; b) concentrating said aqueous mixture including stabilized cerium dioxide nanoparticles to form an aqueous concentrate; and c) combining said concentrate with said surfactant and said nonpolar solvent, thereby forming said homogeneous mixture. - View Dependent Claims (109, 110, 111, 112, 113, 114, 115, 116, 117)
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Specification