The aqueous phase oxidation of gaseous elemental mercury (Hg0) by potassium persulfate (KPS) catalyzed by Ag+ was investigated using a glass bubble column reactor. Concentration of gaseous mercury and potassium persul...The aqueous phase oxidation of gaseous elemental mercury (Hg0) by potassium persulfate (KPS) catalyzed by Ag+ was investigated using a glass bubble column reactor. Concentration of gaseous mercury and potassium persulfate were measured by cold vapor atom absorption (CVAA) and ion chromatograph (IC), respectively. The effects of pH value, concentration of potassium persulfate and silver nitrate (SN), temperature, Hg0 concentration in the reactor inlet and tertiary butanol (TBA), free radical scavenger, on the removal efficiency of Hg0 were studied. The results showed that the removal efficiency of Hg0 increased with increasing concentration of potassium persulfate and silver nitrate, while temperature and TBA were negatively effective. Furthermore, the removal efficiency of Hg0 was much better in neutral solution than in both acidic and alkaline solution. But the influence of pH was almost eliminated by adding AgNO3. High Hg0 concentration has positive effect. The possible reaction mechanism of gaseous mercury was also discussed.展开更多
Using catalytic oxidative absorption for H_2S removal is of great interest due to its distinct advantages. However,traditional scrubbing process faces a great limitation in the confined space. Therefore, there is an u...Using catalytic oxidative absorption for H_2S removal is of great interest due to its distinct advantages. However,traditional scrubbing process faces a great limitation in the confined space. Therefore, there is an urgent demand to develop high-efficiency process intensification technology for such a system. In this article, H_2S absorption experimental research was conducted in a rotating packed bed(RPB) reactor with ferric chelate absorbent and a mixture of N_2 and H_2S, which was used to simulate natural gas. The effects of absorbent p H value, gas–liquid ratio, gravity level of RPB, absorption temperature and character of the packing on the desulfurization efficiency were investigated. The results showed that H_2S removal efficiency could reach above 99.6% under the most of the experimental condition and above 99.9% under the optimal condition. A long-time continuous experiment was conducted to investigate the stability of the whole process combining absorption and regeneration. The result showed that the process could well realize simultaneous desulfurization and absorbent regeneration, and the H_2S removal efficiency kept relatively stable in the whole duration of 72 h. It can be clearly seen that high gravity technology desulfurization process, which is simple, high-efficiency, and space intensive, has a good prospect for industrial application of H_2S removal in confined space.展开更多
Novel magnetically recyclable Pd/γ-AlOOH@Fe3O4 catalysts were prepared using γ-AlOOH@Fe3O4 as a magnetic supporter and nano-Pd particles as the active catalytic component.The structure of the catalysts was character...Novel magnetically recyclable Pd/γ-AlOOH@Fe3O4 catalysts were prepared using γ-AlOOH@Fe3O4 as a magnetic supporter and nano-Pd particles as the active catalytic component.The structure of the catalysts was characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),N2 adsorption-desorption,and a vibration sample magnetometer(VSM).The catalytic activity and recyclability for the Heck coupling reaction were investigated.Results showed that the magnetic γ-AlOOH@Fe3O4 possessed a core-shell structure,as well as that the nano-Pd particles were 6–8 nm and had been well dispersed in the γ-AlOOH shell.In the Heck coupling reactions,the magnetic Pd/γ-AlOOH@Fe3O4 catalysts exhibited good catalytic activity and recyclability.For the(0.021 mol%)Pd/γ-AlOOH@Fe3O4 catalyst,the bromobenzene conversion and product yield reached about 100%and 96.3%,respectively,under a 120°C reaction temperature and 12 h reaction time.After being recycled 8 times,the conversion of bromobenzene and the recovery of the catalyst were about 90%and 93%,respectively.The nano-Pd particles were kept well dispersed in the used Pd/γ-AlOOH@Fe3O4 catalyst.展开更多
A variety of unique Al(salen) complexes functionalized by imidazolium-based ionic liquid(IL) moieties with the salen ligand at the two sides of 3,3′-position have been successfully prepared, rather than familiar 5,5...A variety of unique Al(salen) complexes functionalized by imidazolium-based ionic liquid(IL) moieties with the salen ligand at the two sides of 3,3′-position have been successfully prepared, rather than familiar 5,5′-position reported previously.The catalytic activity obtained by these bifunctional catalysts could be superior to those of the binary type catalysts in the formation of five-membered heterocyclic compounds from the cycloaddition reaction of CO_2 and three-membered heterocyclic compounds(including terminal epoxides and N-substituted aziridines), presumably due to the distinguished intramolecularly synergistic catalysis, which might lead to perform the cycloaddition reaction at ambient conditions and retain excellent yield and unprecedented chemo-or regioselectivity. Moreover, the polyether-based trifunctional Al(salen) catalysts with the best catalytic performance could be regenerated and reused at least eight times without any obvious decreases in catalytic activity. Finally,the kinetic investigation suggested the structure of catalysts had important influences on the catalytic activity, thereby proposing the possible reaction mechanism.展开更多
Due to the unique interface and electronic structure,metal/metal oxide composite electrocatalysts have been designed and exploited for electrocatalytic oxygen evolution reaction(OER)in alkaline solution.However,how to...Due to the unique interface and electronic structure,metal/metal oxide composite electrocatalysts have been designed and exploited for electrocatalytic oxygen evolution reaction(OER)in alkaline solution.However,how to fabricate metal/metal oxides with abundant interfaces and well-dispersed metal phases is a challenge,and the synergistic effect between metal and metal oxides on boosting the electrocatalytic activities is still ambiguous.Herein,by controlling the lithium-induced conversion reaction of metal oxides,metal/metal oxide composites with plentiful interfaces and excellent electrical interconnection are fabricated,which can enhance the active sites,and accelerate the mass transfer during the electrocatalytic reaction.As a result,the electrocatalytic oxygen evolution activities of the as-fabricated metal/metal oxide composite catalysts including NiCo/NiCo2O4,NiMn/NiMn2O4 and CoMn/CoMn2O4 are greatly improved.The catalytic mechanism is also explored using the in-situ X-ray and Raman spectroscopic tracking to uncover the real active centers and the synergistic effect between the metal and metal oxides during water oxidation.Density functional theory plus U(DFT+U)calculation confirms the metal in the composite can optimize the catalytic reaction path and reduce the reaction barrier,thus boosting the electrocatalytic kinetics.展开更多
基金Project (No. 20476094) supported by the National Natural ScienceFoundation of China
文摘The aqueous phase oxidation of gaseous elemental mercury (Hg0) by potassium persulfate (KPS) catalyzed by Ag+ was investigated using a glass bubble column reactor. Concentration of gaseous mercury and potassium persulfate were measured by cold vapor atom absorption (CVAA) and ion chromatograph (IC), respectively. The effects of pH value, concentration of potassium persulfate and silver nitrate (SN), temperature, Hg0 concentration in the reactor inlet and tertiary butanol (TBA), free radical scavenger, on the removal efficiency of Hg0 were studied. The results showed that the removal efficiency of Hg0 increased with increasing concentration of potassium persulfate and silver nitrate, while temperature and TBA were negatively effective. Furthermore, the removal efficiency of Hg0 was much better in neutral solution than in both acidic and alkaline solution. But the influence of pH was almost eliminated by adding AgNO3. High Hg0 concentration has positive effect. The possible reaction mechanism of gaseous mercury was also discussed.
基金Supported by the National Natural Science Foundation of China(21406008)
文摘Using catalytic oxidative absorption for H_2S removal is of great interest due to its distinct advantages. However,traditional scrubbing process faces a great limitation in the confined space. Therefore, there is an urgent demand to develop high-efficiency process intensification technology for such a system. In this article, H_2S absorption experimental research was conducted in a rotating packed bed(RPB) reactor with ferric chelate absorbent and a mixture of N_2 and H_2S, which was used to simulate natural gas. The effects of absorbent p H value, gas–liquid ratio, gravity level of RPB, absorption temperature and character of the packing on the desulfurization efficiency were investigated. The results showed that H_2S removal efficiency could reach above 99.6% under the most of the experimental condition and above 99.9% under the optimal condition. A long-time continuous experiment was conducted to investigate the stability of the whole process combining absorption and regeneration. The result showed that the process could well realize simultaneous desulfurization and absorbent regeneration, and the H_2S removal efficiency kept relatively stable in the whole duration of 72 h. It can be clearly seen that high gravity technology desulfurization process, which is simple, high-efficiency, and space intensive, has a good prospect for industrial application of H_2S removal in confined space.
基金supported by the National Natural Science Foundation of China(21173018)
文摘Novel magnetically recyclable Pd/γ-AlOOH@Fe3O4 catalysts were prepared using γ-AlOOH@Fe3O4 as a magnetic supporter and nano-Pd particles as the active catalytic component.The structure of the catalysts was characterized by X-ray diffraction(XRD),transmission electron microscopy(TEM),N2 adsorption-desorption,and a vibration sample magnetometer(VSM).The catalytic activity and recyclability for the Heck coupling reaction were investigated.Results showed that the magnetic γ-AlOOH@Fe3O4 possessed a core-shell structure,as well as that the nano-Pd particles were 6–8 nm and had been well dispersed in the γ-AlOOH shell.In the Heck coupling reactions,the magnetic Pd/γ-AlOOH@Fe3O4 catalysts exhibited good catalytic activity and recyclability.For the(0.021 mol%)Pd/γ-AlOOH@Fe3O4 catalyst,the bromobenzene conversion and product yield reached about 100%and 96.3%,respectively,under a 120°C reaction temperature and 12 h reaction time.After being recycled 8 times,the conversion of bromobenzene and the recovery of the catalyst were about 90%and 93%,respectively.The nano-Pd particles were kept well dispersed in the used Pd/γ-AlOOH@Fe3O4 catalyst.
基金supported by the National Science for Distinguished Young Scholars of China(21425627)the National Natural Science Foundation of China(21676306)+1 种基金the Natural Science Foundation of Guangdong Province(2016A030310211,2015A030313104)the Fundamental Research Funds for the Central Universities of Sun Yat-sen University
文摘A variety of unique Al(salen) complexes functionalized by imidazolium-based ionic liquid(IL) moieties with the salen ligand at the two sides of 3,3′-position have been successfully prepared, rather than familiar 5,5′-position reported previously.The catalytic activity obtained by these bifunctional catalysts could be superior to those of the binary type catalysts in the formation of five-membered heterocyclic compounds from the cycloaddition reaction of CO_2 and three-membered heterocyclic compounds(including terminal epoxides and N-substituted aziridines), presumably due to the distinguished intramolecularly synergistic catalysis, which might lead to perform the cycloaddition reaction at ambient conditions and retain excellent yield and unprecedented chemo-or regioselectivity. Moreover, the polyether-based trifunctional Al(salen) catalysts with the best catalytic performance could be regenerated and reused at least eight times without any obvious decreases in catalytic activity. Finally,the kinetic investigation suggested the structure of catalysts had important influences on the catalytic activity, thereby proposing the possible reaction mechanism.
基金the National Natural Science Foundation of China(21603157)Young Elite Scientists Sponsorship Program by CAST(2018QNRC001)the support of Suzhou Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies and Soochow University Analysis and Testing Center。
文摘Due to the unique interface and electronic structure,metal/metal oxide composite electrocatalysts have been designed and exploited for electrocatalytic oxygen evolution reaction(OER)in alkaline solution.However,how to fabricate metal/metal oxides with abundant interfaces and well-dispersed metal phases is a challenge,and the synergistic effect between metal and metal oxides on boosting the electrocatalytic activities is still ambiguous.Herein,by controlling the lithium-induced conversion reaction of metal oxides,metal/metal oxide composites with plentiful interfaces and excellent electrical interconnection are fabricated,which can enhance the active sites,and accelerate the mass transfer during the electrocatalytic reaction.As a result,the electrocatalytic oxygen evolution activities of the as-fabricated metal/metal oxide composite catalysts including NiCo/NiCo2O4,NiMn/NiMn2O4 and CoMn/CoMn2O4 are greatly improved.The catalytic mechanism is also explored using the in-situ X-ray and Raman spectroscopic tracking to uncover the real active centers and the synergistic effect between the metal and metal oxides during water oxidation.Density functional theory plus U(DFT+U)calculation confirms the metal in the composite can optimize the catalytic reaction path and reduce the reaction barrier,thus boosting the electrocatalytic kinetics.