| Summary: | 碩士 === 國立中央大學 === 化學研究所 === 96 === Hydrothermally stable periodic mesoporous organosilicas with cubic Pm3n frame structures were synthesized by using tetraethoxysilane (TEOS) and 1,2-bis(triethoxysilyl)ethane (BTEE) as silica source and cetyltriethylammonium bromide (CTEABr) as surfactant under acidic conditions.The synthesized materials were characterized by PXRD, SEM, N2 adsorption-desorption, 29Si MAS NMR, 13C CP MAS NMR and TG-DTA techniques. Hydrothermal stability of the synthesized material was evaluated by refluxing the sample under boiling water for various time periods and the results were compared with pure mesoporous silica material (Si-SBA-1). The results showed that the hybrid material is stable up to 5 days in boiling water with a slight decrease in structural properties, whereas Si-SBA-1 structure was collapsed after refluxing for one day. The improved hydrothermal stability of hybrid material is related to more hydrophobic environment induced inside the pore channels due to the presence of integrating ethane groups in the walls of the channels.
On the synthesis of organosulfonic acid-functionalized mesoporous in a one-step approach of co-condensing inorganic–organic reagents in the presence of cetyltriethylammonium bromide (CTEABr) surfactant with in situ oxidation of the thiol groups to the sulfonic acid groups.It is a one-step condensation of tetramethoxysilane (TEOS) and 3-mercaptopropyltrimethoxysilane (MPTMS) in highly acidic medium. During the condensation process, the in situ oxidation of thiol (-SH) group to sulfonic acid (-SO3H) group was facilitated by hydrogen peroxide (30 wt % H2O2). Adsorption and structural properties of the aforementioned PMOs have been studied by nitrogen adsorption and X-ray diffraction, whereas their framework chemistry was quantitatively analyzed by solid-state 13C and 29Si MAS NMR.
The detection and quantification of heavy metal ions are important in plethora of areas such as environmental monitoring, waste water management, developmental biology, and clinical toxicology. A number of techniques have been developed over the years for heavy metal ion analysis. Now, we used solid-state 13C CPMAS (cross polarization magic angle spinning) NMR spectroscopy as a characterization tools to obtain spectroscopic evidence for the heavy metal adsorption. By the way, the conversion of thiol-functionalized SBA-1 to disulfide-functionalized SBA-1 using Cu2+ without hydrogen peroxide was achieved.
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