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  • spherical
  • The Stöber process is a sol-gel approach to preparing monodisperse (uniform) spherical silica (SiO 2) materials that was developed by a team led by Werner Stöber and reported in 1968. (wikipedia.org)
  • Diameter
  • Type A - clear pellets, approximate pore diameter: 2.5 nm, drying and moistureproof properties, can be used as catalyst carriers, adsorbents, separators and variable-pressure adsorbent. (wikipedia.org)
  • Type B - translucent white pellets, pore diameter: 4.5-7.0 nm, liquid adsorbents, drier and perfume carriers, also may be used as catalyst carriers, cat litter. (wikipedia.org)
  • particles
  • The Stöber process is a chemical process used to prepare silica (SiO 2) particles of controllable and uniform size for applications in materials science. (wikipedia.org)
  • In 1999 a two-stage modification was reported that allowed the controlled formation of silica particles with small holes. (wikipedia.org)
  • The non-ionic surfactant is burned away to produce empty pores, increasing the surface area and altering the surface characteristics of the resulting particles, allowing for much greater control over the physical properties of the material. (wikipedia.org)
  • These particles also have a hexagonal array of pores. (wikipedia.org)
  • Mesoporous particles can also be synthesized using a simple sol-gel method such as the Stöber process, or a spray drying method. (wikipedia.org)
  • citation needed] The large surface area of the pores allows the particles to be filled with a drug or a cytotoxin. (wikipedia.org)
  • These particles are optically transparent, so the dye can be seen through the silica walls. (wikipedia.org)
  • The process involves conversion of monomers into a colloidal solution (sol) that acts as the precursor for an integrated network (or gel) of either discrete particles or network polymers. (wikipedia.org)
  • In this chemical procedure, the "sol" (or solution) gradually evolves towards the formation of a gel-like diphasic system containing both a liquid phase and solid phase whose morphologies range from discrete particles to continuous polymer networks. (wikipedia.org)
  • In the case of the colloid, the volume fraction of particles (or particle density) may be so low that a significant amount of fluid may need to be removed initially for the gel-like properties to be recognized. (wikipedia.org)
  • monoliths
  • These pores provide monoliths with high permeability, a large number of channels, and a high surface area available for reactivity. (wikipedia.org)
  • Packed particle columns have pore connectivity values of about 1.5, while monoliths have values ranging from 6 to greater than 10. (wikipedia.org)
  • Packets
  • Since such packets may resemble sachets of sugar or salt and because silica gel may have added toxic chemical indicators (see below), silica gel packets usually bear warnings for the user not to eat the contents. (wikipedia.org)
  • Through the inclusion of silica gel packets, these items can be preserved longer. (wikipedia.org)
  • supercritical
  • Applying supercritical drying techniques, a Stöber silica aerogel with a specific surface area of 700 m2 g−1 and a density of 0.040 g cm−3 can be prepared. (wikipedia.org)
  • It may be a liquid (LC and Capillary Electrochromatography (CEC)), a gas (GC), or a supercritical fluid (supercritical-fluid chromatography, SFC). (wikipedia.org)
  • porosity
  • The rate at which the solvent can be removed is ultimately determined by the distribution of porosity in the gel. (wikipedia.org)
  • catalyst
  • Silica Gel Type B can be used as air humidity modifier, catalyst carrier, etc. (guidechem.com)
  • In World War II, silica gel was indispensable in the war effort for keeping penicillin dry, protecting military equipment from moisture damage[citation needed], as a fluid cracking catalyst for the production of high octane gasoline, and as a catalyst support for the manufacture of butadiene from ethanol, feedstock for the synthetic rubber program. (wikipedia.org)
  • Additionally dried and screened, it forms macro-pored silica gel which is used as drier, adsorbent and catalyst carrier. (wikipedia.org)
  • elution
  • Because of the abundant separating columns, elution systems, and detectors available, chromatography has developed into the main method for ion analysis. (wikipedia.org)
  • Beads
  • Silica gel is most commonly encountered in everyday life as beads in a small (typically 2 x 3 cm) paper packet. (wikipedia.org)
  • in these configurations, tiny beads of an inert substance, typically a modified silica, are used inside the column. (wikipedia.org)
  • sodium
  • An aqueous solution of sodium silicate is acidified to produce a gelatinous precipitate that is washed, then dehydrated to produce colorless silica gel. (wikipedia.org)
  • By a thermal treatment, an interpenetration structure is generated, which results from a spinodal decomposition of the sodium-rich borate phase and the silica phase. (wikipedia.org)
  • molecular
  • 8. The device of claim 1 wherein said osteogenic protein has a molecular weight of about 30 kD when oxidized as determined by comparison to molecular weight standards in SDS-polyacrylamide gel electrophoresis. (google.com)
  • 10. The device of claim 1 wherein one of said pair of polypeptide chains has a molecular weight of about 16 kD and the other has a molecular weight of about 18 kD, both as determined after reduction by comparison to molecular weight standards in SDS-polyacrylamide gel electrophoresis. (google.com)
  • Other molecular sieves are used as desiccants (some examples include activated charcoal and silica gel). (wikipedia.org)
  • process
  • With advanced process, wide product line and stable quality, we can meet demands for silica gel from various industries. (guidechem.com)
  • Focus on the latest chromatography technologies such as preparative and process chromatography to optimize the current and standard opportunities to optimize chromatography process in proper way. (sorbeadindia.com)
  • Process chromatography technology is utilized on a large scale with dynamic binding capacity. (sorbeadindia.com)
  • Gravity chromatography is a manual process of require continuously observed. (sorbeadindia.com)
  • Silica produced using the Stöber process is an ideal material to serve as a model for studying colloid phenomena because of the monodispersity (uniformity) of its particle sizes. (wikipedia.org)
  • NASA has prepared silica aerogels with a Stöber-process approach for both the Mars Pathfinder and Stardust missions. (wikipedia.org)
  • Ritsko, J. E. and Vanderpool, C. D. "Process for producing low-bulk density silica. (wikipedia.org)
  • During a sintering process after extraction, a silica glass is generated, which has properties approaching those of quartz glass. (wikipedia.org)
  • The manufacturing of such high-silica glasses has been published as the VYCOR-process. (wikipedia.org)
  • Sol-gel research grew to be so important that in the 1990s more than 35,000 papers were published worldwide on the process. (wikipedia.org)
  • The sol-gel process is a wet-chemical technique used for the fabrication of both glassy and ceramic materials. (wikipedia.org)
  • high
  • Yudong silica is specialized in production of high quality silica gel. (guidechem.com)
  • It was in the fifties and sixties that theoretical models were developed for IC for further understanding and it was not until the seventies that continuous detectors were utilized, paving the path for the development from low-pressure to high-performance chromatography. (wikipedia.org)
  • Silica gel may also be used to keep the relative humidity (RH) inside a high frequency radio or satellite transmission system waveguide as low as possible (see also Humidity buffering). (wikipedia.org)
  • They show a high chemical, thermal and mechanical resistance, which results from a rigid and incompressible silica network. (wikipedia.org)
  • They can be produced in high quality and with pore sizes ranging from 1 nm up to any desired value. (wikipedia.org)
  • technique
  • Chromatography technique developed substantially as a result of the work of Archer John Porter Martin and Richard Laurence Millington Synge during the 1940s and 1950s, for which they won the 1952 Nobel Prize in Chemistry. (wikipedia.org)
  • The sol-gel approach is a cheap and low-temperature technique that allows the fine control of the product's chemical composition. (wikipedia.org)
  • thermal
  • Highly effective thermal insulators known as aerogels can also be prepared using Stöber methods, and Stöber techniques have been applied to prepare non-silica aerogel systems. (wikipedia.org)
  • diameter
  • Eventually, chemists were using coiled glass or fused silica capillary tubes less than a millimeter in diameter and many yards long. (encyclopedia.com)
  • Type A - clear pellets, approximate pore diameter: 2.5 nm, drying and moistureproof properties, can be used as catalyst carriers, adsorbents, separators and variable-pressure adsorbent. (wikipedia.org)
  • Type B - translucent white pellets, pore diameter: 4.5-7.0 nm, liquid adsorbents, drier and perfume carriers, also may be used as catalyst carriers, cat litter. (wikipedia.org)
  • The reason for their success is related to their specific features in converting molecules having kinetic diameter below 1 nm, but they become inadequate when reactants with sizes above the dimensions of the pores have to be processed. (wikipedia.org)
  • Research efforts to synthesize zeolites with larger pore diameter, high structural stability and catalytic activity have not given the expected results yet. (wikipedia.org)
  • 1000
  • By regulating the manufacturing parameters, it is possible to produce a porous glass with a pore size of between 0.4 and 1000 nm in a very narrow pore size distribution. (wikipedia.org)
  • Chemistry
  • citation needed] The synthetic route for producing silica gel was patented by chemistry professor Walter A. Patrick at Johns Hopkins University in 1918. (wikipedia.org)
  • Chromatography technique developed substantially as a result of the work of Archer John Porter Martin and Richard Laurence Millington Synge during the 1940s and 1950s, for which they won the 1952 Nobel Prize in Chemistry. (wikipedia.org)
  • typically
  • Silica gel is most commonly encountered in everyday life as beads in a small (typically 2 x 3 cm) paper packet. (wikipedia.org)
  • in these configurations, tiny beads of an inert substance, typically a modified silica, are used inside the column. (wikipedia.org)
  • membranes
  • 20,21 Briefly, the liquid sample is passed through a series of hollow fiber membranes with pore size ranging from 1,000 kD to 10 kD. (jove.com)
  • oxides
  • The present invention relates to a zeolite based on silica and tetravalent element oxides selected from tin and zirconium. (google.com)
  • material
  • Silica produced using the Stöber process is an ideal material to serve as a model for studying colloid phenomena because of the monodispersity (uniformity) of its particle sizes. (wikipedia.org)
  • Type C - translucent, micro-pored structure, raw material for preparation of silica gel cat litter. (wikipedia.org)
  • In scientific literature, porous glass is a porous material containing approximately 96% silica, which is produced by an acidic extraction or a combined acidic and alkaline extraction respectively, of phase separated alkali borosilicate glasses, and features a three-dimensional interconnected porous microstructure. (wikipedia.org)
  • penetration
  • Initially, the diaphragm may also contain a water-soluble surfactant to assist in initial water penetration into the pores of the composite. (google.es)