Abstract:
A method of making cerium dioxide nanoparticles includes: a) providing an aqueous reaction mixture having a source of cerous ion, a source of hydroxi de ion, a nanoparticle stabilizer, and an oxidant at an initial temperature no higher than about 2O°C; b) mechanically shearing the mixture and causing it to pass through a perforated screen, thereby forming a suspension of ceri um hydroxide nanoparticles; and c) raising the initial temperature to achiev e oxidation of cerous ion to eerie ion and thereby form cerium dioxide nanop articles having a mean diameter in the range of about 1 nm to about 15 nm. T he cerium dioxide nanoparticles may be formed in a continuous process.
Abstract:
Un proceso para hacer nanopartículas de dióxido de cerio que contienen al menos un material de transición (M) que comprende (a) proporcionar una mezcla de reacción acuosa que contiene una fuente de ión ceroso, una fuente de uno o más iones metálicos de transición (M), una fuente de ión de hidróxido, al menos un estabilizador de nanopartículas, y un oxidante a una temperatura inicial en un rango de alrededor de 200C alrededor de 950C; (b) cortar mecánicamente la mezcla y provocar que pase a través de una pantalla perforada, formando así una suspensión homogéneamente distribuída de nanopartículas de hidróxido de cerio; y (c) proporcionar condiciones de temperatura efectivas para lograr la oxidación de ión ceroso a ión cérico, formando así una corriente de producto que contiene nanopartículas de dióxido de cerio que contienen metal de transición, Ce1-xMxO2, en donde "x" tiene un valor de alrededor de 0.3 a alrededor de 0.8. Las nanopartículas así obtenidas, tienen una estructura de fluorita cúbica, una media de diámetro hidrodinámico en un rango de alrededor de 1 nm a alrededor de 10nm, y un diámetro geométrico menor a alrededor de 4 nm. Las nanopartículas cristalinas de dióxido de cerio que contienen metal de transición pueden usarse para preparar una dispersión de las partículas en un medio no polar.
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 2O°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.
Abstract:
A method of Improving the efficiency of a diesel engine provided with a s ource of diesel fuel includes the steps of: a) adding to the diesel fuel a r everse-micellar composition having an aqueous first disperse phase that incl udes a free radical initiator and a first continuous phase that includes a f irst hydrocarbon liquid, a first surfactant, and optionally a co-surfactant, thereby producing a modified diesel fuel; and b) operating the engine, ther eby combusting the modified diesel fuel. The efficiency of a diesel engine p rovided with a source of diesel fuel and a source of lubricating oil can als o be improved by modifying the lubricating oil by the addition of a stabiliz ed nanoparticulate composition of cerium dioxide. The efficiency of a diesel engine can also be improved by adding to the diesel fuel a reverse-micellar composition that includes an aqueous disperse phase containing boric acid o r a borate salt.
Abstract:
A fuel additive composition includes: a) a reverse-micellar composition h aving an aqueous disperse phase that includes cerium dioxide nanoparticles i n a continuous phase that includes a hydrocarbon liquid, a surfactant, and o ptionally a co-surfactant and b) a reverse micellar composition having an aq ueous disperse phase that includes a cetane improver effective for improving engine power during fuel combustion. A method of making a cerium-containing fuel additive includes the steps of: a) providing a mixture of a nonpolar s olvent, a surfactant, and a co-surfactant; and b) combining the mixture with an aqueous suspension of stabilized cerium dioxide nanoparticles.
Abstract:
A process for making cerium-containing oxide nanoparticles includes providing an aqueous reaction mixture containing a source of cerous ion, optionally a source of one or more metal ions (M) other than cerium, a source of hydroxide ion, at least one monoether carboxylic acid nanoparticle stabilizer wherein the molar ratio of said monoether carboxylic acid nanoparticle stabilizers 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 95°C. Temperature conditions are provided effective to enable oxidation of cerous ion to ceric ion, thereby forming a product dispersion of cerium-containing oxide nanoparticles, optionally containing one or more metal ions (M), Ce1-xMxO2-d, wherein "x" has a value from about 0.0 to about 0.95. The nanoparticles may have a mean hydrodynamic diameter from about 1 nm to about 50 nm, and a geometric diameter of less than about 45 nm.
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.
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.