Nanocrystalline zeolites surface areas

Castagnola and Dutta investigated the use of nanocrystalline zeolites with high surface area as hosts [18]. The strategy to increase photochemical efficiency was... 

Nanociystalline zeolites (ciystal sizes of less than 100 nm) are porous aluminosilicate nanomaterials with increased surface areas relative to conventional micron-sized zeolites. Nanocrystalline zeolites are potentially useful for CWA decontamination applications because of their enhanced absorptive and catalytic properties. This chapter describes FTIR and solid state NMR studies of the thermal reactivity of two CWA simulants, 2-CEES (2 chloroethyl sulfide) and DMMP (dimethylmethylphosphonate) on nanocrystalline zeohtes, such as NaZSM-5 (sihcalite, purely siliceous form of ZSM-5) and NaY, with crystal sizes of approximately 25 nm. 

Nanocrystalline zeolites, NaY and NaZSM-5 and silicalite, synthesized by us, were evaluated for the decontamination of the CWA simulants, DMMP (15) and 2-CEES (16,17). The increased surface area and external surface reactivity of nanocrystalline zeolites provides potential advantages for CWA decontamination that are not found in conventional zeolite materials. The adsorption capacity and the thermal oxidation of these simulants on nanociystalline zeolites was investigated using FTIR spectroscopy and solid state NMR spectroscopy and the reactivity on different materials was compared. 

Table 1. External and Internal Surface Areas of Nanocrystalline Zeolites...

In parallel to developments in the field of electronics, nanostmctured materials have been developed by materials scientists and chemists also. The concept of nanocrystalline structures emerged in the field of materials science, and polycrystals with ultrafine grain sizes in the nanometer range have been produced. These nanophase materials have been shown to have significant modifications of their mechanical properties compared with the coarse-grain equivalent materials. The huge surface area of nanoporous materials has attracted much attention for applications in chemistry such as molecular sieves, catalysis, and gas sensing. This has motivated intense research aimed at the fabrication of materials with a well-controlled composition and nanoscale stracture, such as synthetic zeolites. 

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