A hierarchical beta zeolite synthesized by quasi-solid phase conversion method was characterized by BET, scanning electron microscope （SEM）, transmission electron microscope （TEM）, X-ray diffraction （XRD）, tempe...A hierarchical beta zeolite synthesized by quasi-solid phase conversion method was characterized by BET, scanning electron microscope （SEM）, transmission electron microscope （TEM）, X-ray diffraction （XRD）, temperature-programmed desorption of ammonia （NH3-TPD）, 27A1 and 295i magic angle spinning nuclear magnetic resonance （27A1 and 29Si MAS NMR）, and its catalytic performance was compared with that of conventional microporous beta zeolite for liquid phase transalkylation of multi-secbutylbenzenes （MSBBs） with benzene. The results indicate that the hierarchical beta zeolite consists of nanosized crystals with a meso/ microporous structure and has stronger acid strength than the microporous beta zeolite. The higher conversion oftri-secbutylbenzene （TSBB） and selectivity ofsec-butylbenzene （SBB） are achieved on hierarchical beta zeolite than microporous beta zeolite, while the conversion of di-secbutylbenzene （DSBB） is slightly higher. The improvement of catalytic performance over hierarchical beta zeolite can be ascribed to the presence of mesopores, nanosized crystals and stronger acidity.展开更多
Based on the principle of bacterial leaching and bacterial metallurgy,a novel technology for the detoxification of chromium-containing slag by Achromobacter sp.CH-1 and chromium recovery was proposed.Strain CH-1 cell ...Based on the principle of bacterial leaching and bacterial metallurgy,a novel technology for the detoxification of chromium-containing slag by Achromobacter sp.CH-1 and chromium recovery was proposed.Strain CH-1 cell morphology before and after Cr(Ⅵ) reduction was observed with a scanning electron microscope(SEM),and the reduction product is found to adhere to terminals of CH-1 cells.Energy-dispersive X-ray(EDX) and electron paramagnetic resonance(EPR) analyses reveal that the main component of the reduction product is Cr(Ⅲ).Furthermore,small and large-scale demonstration projects reveal that Achromobacter sp.can be used to detoxify chromium-containing slag and to selectively recover chromium by using this novel technique.Chromium recovery rate increases with decreasing particle sizes of chromium-containing slag and slagheap height.Chromium recovery rates in 10 t/batch and 20 t/batch of on-site demonstration projects for chromium-containing slag detoxification are more than 90%.展开更多
Mesoporous alumina was prepared by using starch as the structure-directing template in an aqueous system. The resultant samples were characterized by using different methods such as the X-ray diffractometry,the transm...Mesoporous alumina was prepared by using starch as the structure-directing template in an aqueous system. The resultant samples were characterized by using different methods such as the X-ray diffractometry,the transmission electron microscopy,the nitrogen adsorption-desorption analysis and the solid MAS NMR. The results showed that the prepared mesoporous γ-alumina had high surface area and uniform pore size distribution,and its specific surface area and the pore size could be tuned by changing the pH value of the starting solution.展开更多
文摘A hierarchical beta zeolite synthesized by quasi-solid phase conversion method was characterized by BET, scanning electron microscope （SEM）, transmission electron microscope （TEM）, X-ray diffraction （XRD）, temperature-programmed desorption of ammonia （NH3-TPD）, 27A1 and 295i magic angle spinning nuclear magnetic resonance （27A1 and 29Si MAS NMR）, and its catalytic performance was compared with that of conventional microporous beta zeolite for liquid phase transalkylation of multi-secbutylbenzenes （MSBBs） with benzene. The results indicate that the hierarchical beta zeolite consists of nanosized crystals with a meso/ microporous structure and has stronger acid strength than the microporous beta zeolite. The higher conversion oftri-secbutylbenzene （TSBB） and selectivity ofsec-butylbenzene （SBB） are achieved on hierarchical beta zeolite than microporous beta zeolite, while the conversion of di-secbutylbenzene （DSBB） is slightly higher. The improvement of catalytic performance over hierarchical beta zeolite can be ascribed to the presence of mesopores, nanosized crystals and stronger acidity.
文摘Based on the principle of bacterial leaching and bacterial metallurgy,a novel technology for the detoxification of chromium-containing slag by Achromobacter sp.CH-1 and chromium recovery was proposed.Strain CH-1 cell morphology before and after Cr(Ⅵ) reduction was observed with a scanning electron microscope(SEM),and the reduction product is found to adhere to terminals of CH-1 cells.Energy-dispersive X-ray(EDX) and electron paramagnetic resonance(EPR) analyses reveal that the main component of the reduction product is Cr(Ⅲ).Furthermore,small and large-scale demonstration projects reveal that Achromobacter sp.can be used to detoxify chromium-containing slag and to selectively recover chromium by using this novel technique.Chromium recovery rate increases with decreasing particle sizes of chromium-containing slag and slagheap height.Chromium recovery rates in 10 t/batch and 20 t/batch of on-site demonstration projects for chromium-containing slag detoxification are more than 90%.
文摘Mesoporous alumina was prepared by using starch as the structure-directing template in an aqueous system. The resultant samples were characterized by using different methods such as the X-ray diffractometry,the transmission electron microscopy,the nitrogen adsorption-desorption analysis and the solid MAS NMR. The results showed that the prepared mesoporous γ-alumina had high surface area and uniform pore size distribution,and its specific surface area and the pore size could be tuned by changing the pH value of the starting solution.
