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In this study, different oxidation patterns of coke over 3% Pt-Al 2 O 3 and 3% Pt-SBA-15 catalysts were observed but the same catalytic performance was obtained in the dehydrogenation of propane. The oxidation peaks of coke on 3% Pt-Al 2 O 3 appeared at 416 and 513°C, while only one sharp peak was present at 556°C in the coke oxidation pattern of 3% Pt-SBA-15. Using the XRD patterns, it was confirmed that the structure of the coke formed over the catalysts was the same. The TPO profiles indicated that the relative distance of coke from the metallic phase (coke location) and the oxygen mobility on each support played important roles in the oxidation of coke.

We investigated the nature of coke generated in propane dehydrogenation over supported Pt catalysts by FTIR, NMR, and XPS. NMR and FTIR spectra proved that the coke produced in the reaction contained poly-aromatic rings, which was consistent with the previous result that pregraphite-like coke structure was formed. The XPS results indicated that the coke deposits consisted of sp 2 hybridized carbon. All of the characterizations indicated that the pregraphite-like coke containing the poly-aromatic ring structure was generated over the catalysts during the propane dehydrogenation. Furthermore, the XPS measurement demonstrated that the coke deposits interacted with Pt and the electron density of Pt was enriched through the interaction.

We prepared Fe-impregnated mesoporous silicates to investigate the adsorption of tetracycline in aqueous solution. Mesoporous silicates with different Fe content (5, 10, 30, 50 wt%) were prepared by an incipient wetness method. Adsorption kinetics for tetracycline showed that Fe-impregnation improved the adsorption ability for tetracycline. By fitting the adsorption kinetic data to a pseudo second-order model, we obtained a maximum adsorption amount of tetracycline with Fe 30 SBA-15 (30 wt% Fe-impregnated mesoporous silicates) at 41.7 mg/g. The pH dependency of tetracycline adsorption exhibited a volcano curve where the maximum adsorption onto the Fe 30 SBA-15 sample occurred in the neutral pH region. The introduction of Fe species into the SBA-15 revived the adsorption ability for tetracycline, whereas there was no interaction between tetracycline and SBA-15, a mesoporous silicate. These results suggest that impregnated Fe species produce an effective interaction with tetracycline in an aqueous system.

Five supported Pt catalysts (Pt/SBA-15, Pt/Al 2 O 3 , Pt/MgO, Pt/CeO 2 , and Pt/Ce 0.63 Zr 0.37 O 2 ) were prepared to systematically investigate the influence of oxygen mobility over the support on combustion temperatures of coke produced in propane dehydrogenation. A strong correlation between the oxygen mobility of the supports and the combustion temperature of the coke was observed. The coke combustion temperatures increased following the reverse order of oxygen mobility of the supports: CeZrO 2 [ CeO 2 [ MgO [ Al 2 O 3 [ SBA-15, implying that the oxygen transfer over supports was a ratedetermining step in the coke combustion process.

We prepared La-impregnated mesoporous silicates to investigate the adsorption of tetracycline in aqueous solution. Nitrogen adsorption-desorption isotherm tests confirmed the mesoporosity of the prepared materials, resulting in a decline in surface area and pore volume along with La loading amount. In adsorption tests, however, La impregnation improved the adsorption capacity of materials for tetracycline even though the surface area and the pore volumes were lower after La impregnation. Adsorption capacities for tetracycline showed a maximum value with La loading amounts. The highest adsorption capacity for tetracycline was 303.3 mg g(-1), which was acquired from the fitting of isotherm data of 10 wt% La-impregnated mesoporous silicates to the Langmuir model. Changes in FTIR patterns of tetracycline adsorbed on La-impregnated mesoporous silicates implied that the negatively charged oxygen of the tricarbonylamide group of tetracycline chemically interacted with La hydroxide species in materials in the neutral condition.