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Controllable preparation of particles with microfluidics   总被引:1,自引:0,他引:1  
This paper reviews recent development and achievements in controllable preparation of nanoparticles, micron spherical and non-spherical particles, using microfluidics. A variety of synthesis strategies are presented and compared, including single-phase and multiphase microflows. The main structures of microfluidic devices and the fundamental principles of microflows for particle preparation are summarized and identified. The controllability of particle size, size distribution, crystal structure, morphology, physical and chemical properties, is examined in terms of the special features of microfluidic reactors. An outlook on opinions and predictions concerning the future development of powder technology with microfluidics is specially provided.  相似文献
2.
This paper presents a synthesis process for preparing mesoporous titanium dioxide materials in the absence of any templates and using inorganic acids as catalysts. Tetrabutyl titanate was used as the precursor at ambient temperature, and four different inorganic acids, i.e., hydrochloric, nitric, sulfuric and phosphoric, were used as catalysts. The as-prepared mesoporous TiO2 materials were characterized by SEM, XRD and nitrogen adsorption/desorption measurements. The influences of different inorganic acids on the properties of TiO2 were discussed and compared in details. Experiments showed that the inorganic acids have significant effects on the surface area, pore volume, pore size, and pore size distribution of the products. The mesoporous TiO2 materials catalyzed by phosphoric acid exhibited the largest specific surface area and largest pore volume with narrow pore size distribution. Vacuum and infrared drying methods tested in the process were found to have subtle impact on the structure of the TiO2 materials prepared.  相似文献
3.
A novel method was proposed for the in situ synthesis of magnetite-containing mesoporous silica SBA- 16 via a sol-gel process coupled with precipitation and oxidation. The effect of the added amounts of reactants on the mesostructural and magnetic properties of the magnetic mesoporous silica was investigated. It was determined that the synthesized magnetic mesoporous silica with a total pore volume of 0.64-0.96 cm 3 /g and an average pore diameter of 4.0-14.9 nm had a relatively high saturation magnetizatio...  相似文献
4.
This paper presents the integrated results of a series of new methods for preparing mesoporous silica spheres as high-performance liquid chromatography (HPLC) packing materials. The separation performance of the mesoporous spheres materials has also been determined. Micrometersized silica spheres with uniform spherical morphologies and ordered mesostructures were first successfully synthesized by the method employing a water-soluble polymer-assisted assembly. Then the templates for getting ordered mesoporous materials with high-density silanol groups were removed by using hydrothermal oxidation. Finally the silica spheres were functionalized with C8 alkyl groups by surface modification under hydrothermal conditions. The resultant functionalized silica spheres were demonstrated to be excellent packing materials for HPLC.  相似文献
5.
This paper presents the integrated results of a series of new methods for preparing mesoporous silica spheres as high-performance liquid chromatography (HPLC) packing materials. The separation performance of the mesoporous spheres materials has also been determined. Micrometer- sized silica spheres with uniform spherical morphologies and ordered mesostructures were first successfully synthesized by the method employing a water-soluble polymer-assisted assembly. Then the templates for getting ordered mesoporous materials with high-density silanol groups were removed by using hydrothermal oxidation. Finally the silica spheres were functionalized with C8 alkyl groups by surface modification under hydrothermal conditions. The resultant functionalized silica spheres were demonstrated to be excellent oacking materials for HPLC.  相似文献
6.
A subcritical water treatment method was developed for preparing porous-surfaced glass beads with an egg-shell structure in a batch reactor. Based on the "corrosion-ion-migration-recondensation" strategy, ordinary soda-lime glass beads with a diameter of about 100 m were made first to react with subcritical water to effect controlled quantity of silicate dissolution of glass by adjusting treatment time and temperature. The dissolved silicate was then made to recondense on the glass core to form different porous shell morphologies: pores, flakes and fibers. Among these, glass beads coated with fibers with surface area of 154.5 m2/g, pore volume of 0.27 cm3/g and pore size of 7.1 nm were obtained at 573 K after 2 h of treatment. The prepared porous-surfaced glass beads were then used as adsorbent for heavy metal ions, showing various ion exchange properties. Glass beads covered with fibers displayed fast kinetics and high sorption capacity because of their egg-shell structure and high surface area. More than 90% of copper ions were adsorbed within 100 min from a solution with an initial concentration of 110 mg/L at 313 K. Ion sorption capacities were 149.33, 81.33 and 42.96 mg/g respectively for Ag+, Cu2+ and Ni2+ at 313 K. A green and low-cost method was thus developed to produce egg-shell-structured porous glass with high sorption capacity.  相似文献
7.
1,3,5-trimethyl benzene (TMB) was used as organic swelling agent in O/W emulsions to template ultra-large mesoporous materials using the hydrothermal method. The silicas with well-defined mesopores and hydrothermally robust framework were characterized by X-ray diffraction, transmission electron microscopy and BET surface area analysis. The influence of the quantity of TMB during preparation was studied. It has been found that the TMB/CTAB ratio must be controlled for producing high pore volume materials. Polysulfone (PSU), as the usual extraction agent, was coated on the silicas with the solvent evaporation method to produce a solid separation medium. The adsorptivity and the surface area of the coated MCM were determined: 10% PSU coated MCM adsorbed twice as much phenol as the uncoated material, reaching 0.5 mg/g silica. It was found that the surface area of the coated material decreased rapidly with an increase of the PSU Ioadina.  相似文献
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