Mesopore-modified zeolites: preparation, characterization, and applications.
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Biomedical subjects
Publications and source records attributed to Yousheng Tao.
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Mesoporous zeolite A has been synthesized by using a template method with resorcinol-formaldehyde aerogels having three-dimensional mesopores. It was characterized with X-ray powder diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, field emission scanning electron microscopy, thermogravimetric analysis, and nitrogen adsorption/desorption. The pore size distribution calculated from the nitrogen adsorption isotherm is a bimodal distribution with micropores and mesopores. Field emission scanning electron micrograph observations confirm the presence of mesopores.
Resorcinol-formaldehyde aerogels and carbon aerogels of different mesoporosities have been used as templates for preparing bimodal zeolites of mesopores. Samples were thoroughly characterized with X-ray diffraction, field emission scanning electron microscopy, thermogravimetric analysis, X-ray photoelectron spectroscopy, N(2) adsorption at 77 K, as well as FT-IR spectroscopy and (29)Si nuclear magnetic resonance spectroscopy. The mesoporous ZSM-5 zeolites have additional mesopores of 9-25 nm in widths and 0.07-0.2 cm(3)/g in volumes, besides their perfect inherent micropores. Experimental results show the mesoporous systems of the finally obtained zeolites can be influenced by proper preparation of resorcinol-formaldehyde aerogels and carbon aerogels through solution chemistry. Consequently, zeolites of tunable mesoporosities can be prepared with this unique methodology.
A ZSM-5 monolith of uniform mesopores(meso-ZSM-5) was synthesized with the template method using carbon aerogel of uniform mesopores of great pore volume. The pore size distribution determined by N2 adsorption showed the presence of mesopores with an average pore width of 11 nm and micropores with an average pore width of 0.51 nm. Field emission scanning electron micrograph observation revealed the presence of uniform mesopores. X-ray diffraction and FT-IR provided evidence that the synthesized meso-ZSM-5 monolith has a highly crystalline ZSM-5 structure.