Morphological Control Of Hollow Mesoporous Silica Nanomaterials And Applications In Adsorption

Mesoporous silica material, featured with adjustable pore size, highsurface area, regularpacking pores, etc, has been recognizedas one of the most important materials. It can bewidely applied in catalysis, adsorption,separation, drug delivery, etc.Generally, themesoporous structure of mesoporous materials is derived from thesuper-molecular templatesintroduced during synthesized process, such as polymer or surfactant. Thus, the templatesplays a curial role in the formation of special morphology. In addition, due to lack of activeacid/base centers, the pure silicabased mesoporous material is totally inactive, a lmost nocatalytic activity at all.Therefore, introducing hetero elements into the framework, orsupporting activecomponents nanoparticles on the exterior and interior surface of themesoporousmaterials, becomes important solution to make mesoporous materials usableincatalysis area.Mesoporous silica materialswithvarious special morphology have differentapplication areas, such as, hollow mesoporous silica microspheres can be used for drugdelivery and nucleic acids protect, solid silica microspheres can be applied as the columnpacking, a three-dimensional network structure of mesoporous silica materials can be appliedin the field of coatings, mesoporous silica films have a wide applications in areas ofseparation and gas sensor, as well as silica fiber material has great potential in the field ofoptics.In this work, a series of mesoporous materials with various specialmorphologies andstructures, has been synthesized successfully by using templates. By characterizations ofXRD, FTIR, SEM, TEM, TG/DSC, N2adsorption,etc., the synthesized materials werecharacterized, and the possible mechanism oftemplate-silica self-assemble was investigated.I) With CTAB as pore-formingagent TEOS acted as emulsion template, using a facileemulsion-template method mesoporous silica microspheres (MSM) with high surface area of1766m2/g was synthesized. The effect of synthesized conditions, including solvent composite(Valcohol/Vwater), concentration of CTAB, on the morphology and porosity of MHSS wasinvestigated, the particle size can be adjusted from150nm to820nm and wall thickness can beadjusted from30nm to80nm; MSM wall thick reduced from80nm to40nm, at theconcentration of CTAB increased from0.005M to0.015M.II) With SDS and TMAPS as dual templates, a morphology of nanoparticles, nanotubes,nanorods was synthesised. It’s found that, as the molar ratio of TMAPS/SDS increased, thewallthickness of silicon particles increased and the morphology gradually turn into sphere，nanorod; both of too high temperature or low temperature is bad to synthesis of silica material with special shape, the optimized temperature is30~85℃.III) using CTAB (MSM) as adsorbent, methylene blue adsorption test was investigated.Results indicate that MSM has good adsorption capacity, high pH and temperature of solutiontemperature, low MB concentration is beneficial to MB removal; MB adsorption meets theLangmuir model; When10mg Cu-MSM((20wt%,CuSO4/MSM)) was added into45mg/l ofMB adsoption, MB removal reached92%. Alkaline is favorable to adsorption, the moreamounts of adsorbents, the more dye removal is.