Comparative studies of ozonation alone, ceramic honeycomb-catalyzed and Mn-Fe-K modified ceramic honeycomb catalyzed ozonation processes have been undertaken with benzophenone as the model organic pollutant. The exper...Comparative studies of ozonation alone, ceramic honeycomb-catalyzed and Mn-Fe-K modified ceramic honeycomb catalyzed ozonation processes have been undertaken with benzophenone as the model organic pollutant. The experimental results showed that the presence of Mn-Fe-K modified ceramic honeycombs significantly increased the removal rate of benzophenone and TOC compared with that achieved by ozonation alone or ceramic honeycomb-catalyzed ozonation. The electron paramagnetic resonance (EPR) experiments verified that higher benzophenone removal rate was attribute to more hydroxyl radicals generated in the Mn-Fe-K modified ceramic honeycomb-catalyzed ozonation. Under the conditions of this experiment, the degradation rate of all the three ozonation processes are increasing with the amount of catalyst, temperature and value of pH increased in the solution. We also investigated the effects of different process of ozone addition, the optimum conditions for preparing catalyst and influence of the Mn-Fe-K modified ceramic honeycomb after multiple-repeated use.展开更多
A preferable honeycomb ceramics of Al2TiO5-TiO2-SiO2 doped by CeO2 and Er2O3 with high performance was prepared by means of extrusion molding and the effects of CeO2 and Er2O3 on the mechanical strength, thermal stabi...A preferable honeycomb ceramics of Al2TiO5-TiO2-SiO2 doped by CeO2 and Er2O3 with high performance was prepared by means of extrusion molding and the effects of CeO2 and Er2O3 on the mechanical strength, thermal stability, and sintering temperature of ATS ceramics were mainly investigated. The experimental results and the microscopic analysis by scanning electron microscope, X-ray powder diffxaction, and TG-DSC showed that adding CeO2 and Er2O3 into ATS could prohibit the growth of their crystal grains and make their size uniform, which finally decrease its sintering temperature, and also enhance its mechanical performance as well as thermal stability. After the reforming, ATS doped by 0.5% CeO2 +0.5% Er2O3 was sintered at 1250 ℃, its bending strength reached to 177A MPa and thermal expansion coefficient was 3.8 ~ 10^-6/℃ at 25 - 1000℃, which provided a promising basis of making monolithic honeycomb catalyst of deNOx.展开更多
Monolithic catalysts for CO_(2) methanation have become an active research area for the industrial development of Power-to-Gas technology.In this study,we developed a facile and reproducible synthesis strategy for the...Monolithic catalysts for CO_(2) methanation have become an active research area for the industrial development of Power-to-Gas technology.In this study,we developed a facile and reproducible synthesis strategy for the preparation of structured NiFe catalysts on washcoated cordierite monoliths for CO_(2) methanation.The NiFe catalysts were derived from in-situ grown layered double hydroxides(LDHs)via urea hydrolysis.The influence of different washcoat materials,i.e.,alumina and silica colloidal suspensions on the formation of LDHs layer was investigated,together with the impact of total metal concentration.NiFe LDHs were precipitated on the exterior surface of cordierite washcoated with alumina,while it was found to deposit further inside the channel wall of monolith washcoated with silica due to different intrinsic properties of the colloidal solutions.On the other hand,the thickness of in-situ grown LDHs layers and the catalyst loading could be increased by high metal concentration.The best monolithic catalyst(COR-AluCC-0.5M)was robust,having a thin and well-adhered catalytic layer on the cordierite substrate.As a result,high methane yield was obtained from CO_(2) methanation at high flow rate on this structured NiFe catalysts.The monolithic catalysts appeared as promising structured catalysts for the development of industrial methanation reactor.展开更多
SiC honeycomb ceramics with parallel channels and macroporous walls were prepared by combining extrusion molding with pressureless sintering technology in the presence of starch.The extrusion molding constructed honey...SiC honeycomb ceramics with parallel channels and macroporous walls were prepared by combining extrusion molding with pressureless sintering technology in the presence of starch.The extrusion molding constructed honeycomb structure with parallel channels,while the starch formed spherical macropores on the channel walls.The density and bending strength of SiC honeycomb ceramics decreased with the increase of starch content,while the phase compositions did not vary with the starch content.The control in starch addition could adjust the pore structures on the channel walls of SiC honeycomb ceramics.展开更多
The ozonation of nitrobenzene in aqueous solu-tion was carried out in a semi-batch reactor to investigate the degradation efficiency,the effect factors,and the reaction mechanism,where honeycomb ceramic was used as a ...The ozonation of nitrobenzene in aqueous solu-tion was carried out in a semi-batch reactor to investigate the degradation efficiency,the effect factors,and the reaction mechanism,where honeycomb ceramic was used as a cata-lyst.The presence of honeycomb ceramic could improve the degradation rate of nitrobenzene by 15.46%compared to the results of ozonation alone.Under the conditions of this exper-iment,the degradation rate of honeycomb ceramic-catalyzed ozonation increased by 12.94%with the increase of the amount of catalyst from 1 to 5 blocks.The degradation rates all increased greatly with the increase of temperature and pH of the solution in the processes of honeycomb ceramic-catalyzed ozonation and ozonation alone.But,when the pH of the solution increased to 9.50,the advantage of the honey-comb ceramic-catalyzed ozonation process would be lost.The experimental findings indicated that in the processes of ozonation alone and honeycomb ceramic-catalyzed ozona-tion,nitrobenzene was primarily oxidized by•OH free radical in aqueous solution.The adsorption of nitrobenzene was too limited to have an important influence on the degradation rate of nitrobenzene.With the same total dosage of applied ozone,the multiple step addition of ozone showed much higher removal efficiency than that obtained by one step in the two processes.展开更多
The La-modified Cu-Mn spinel oxide was successfully coated onto honeycomb ceramic by a washcoating method for complete catalytic decomposition of ethyl acetate.The La-modified Cu-Mn oxides were characterized by X-ray ...The La-modified Cu-Mn spinel oxide was successfully coated onto honeycomb ceramic by a washcoating method for complete catalytic decomposition of ethyl acetate.The La-modified Cu-Mn oxides were characterized by X-ray diffraction,X-ray fluorescence,H_(2)-temperature programmed reduction,Brunauer-Emmett-Teller method,field-emission scanning electron microscopy and high-resolution transmission electron microscopy.The effects of different precipitants and rare earth doping on the structure and catalytic performance of the catalysts were investigated.The results show that the CuMn_(2)O_(4) spinel with(NH_(4))_(2)CO_(3) as a precipitant can form a larger specific surface area and a suitable pore size,which is beneficial to the absorption of ethyl acetate.Although the rare earth doping does not significantly change the crystal phase structure of the catalyst,it improves its reducibility and lowers the temperature of the catalytic decomposition.With respect to the catalytic decomposition of ethyl acetate,the rare earth-modified Cu-Mn oxide supported on honeycomb ceramic shows excellent catalytic performance with 100% conversion under the conditions of 239℃,space velocity of 12500 h^(-1) and 1000 ppm.And the ethyl acetate removal rate is still 100% after 1440 min of continuous reaction.展开更多
Nanolaminated Ti3AlC2honeycomb monolith with parallel and uniform holes has been prepared through a facile extrusion route by using Ti3AlC2powder as the main raw material.The fabricated honeycomb monolith has high com...Nanolaminated Ti3AlC2honeycomb monolith with parallel and uniform holes has been prepared through a facile extrusion route by using Ti3AlC2powder as the main raw material.The fabricated honeycomb monolith has high compressive strength of 133 ± 11 and 59 ± 9 MPa,along and perpendicular to the extrusion direction,respectively.It also has good electrical conductivity,and excellent match of thermal expansion coefficient with the washcoat material of γ-AI2O3.These combined properties endow the honeycomb monolith a promising candidate as catalysis substrate for cleaning vehicle exhaust.展开更多
基金The National Natural Science Foundation of China (No. 50378028)
文摘Comparative studies of ozonation alone, ceramic honeycomb-catalyzed and Mn-Fe-K modified ceramic honeycomb catalyzed ozonation processes have been undertaken with benzophenone as the model organic pollutant. The experimental results showed that the presence of Mn-Fe-K modified ceramic honeycombs significantly increased the removal rate of benzophenone and TOC compared with that achieved by ozonation alone or ceramic honeycomb-catalyzed ozonation. The electron paramagnetic resonance (EPR) experiments verified that higher benzophenone removal rate was attribute to more hydroxyl radicals generated in the Mn-Fe-K modified ceramic honeycomb-catalyzed ozonation. Under the conditions of this experiment, the degradation rate of all the three ozonation processes are increasing with the amount of catalyst, temperature and value of pH increased in the solution. We also investigated the effects of different process of ozone addition, the optimum conditions for preparing catalyst and influence of the Mn-Fe-K modified ceramic honeycomb after multiple-repeated use.
基金Project supported by National High Technology Research and Development Program of China (863 Program,2006AA02Z211)Nation-al Natural Science Foundation of China (20376034)Natural Science Foundation of Jiangsu Province (BK2006181)
文摘A preferable honeycomb ceramics of Al2TiO5-TiO2-SiO2 doped by CeO2 and Er2O3 with high performance was prepared by means of extrusion molding and the effects of CeO2 and Er2O3 on the mechanical strength, thermal stability, and sintering temperature of ATS ceramics were mainly investigated. The experimental results and the microscopic analysis by scanning electron microscope, X-ray powder diffxaction, and TG-DSC showed that adding CeO2 and Er2O3 into ATS could prohibit the growth of their crystal grains and make their size uniform, which finally decrease its sintering temperature, and also enhance its mechanical performance as well as thermal stability. After the reforming, ATS doped by 0.5% CeO2 +0.5% Er2O3 was sintered at 1250 ℃, its bending strength reached to 177A MPa and thermal expansion coefficient was 3.8 ~ 10^-6/℃ at 25 - 1000℃, which provided a promising basis of making monolithic honeycomb catalyst of deNOx.
文摘Monolithic catalysts for CO_(2) methanation have become an active research area for the industrial development of Power-to-Gas technology.In this study,we developed a facile and reproducible synthesis strategy for the preparation of structured NiFe catalysts on washcoated cordierite monoliths for CO_(2) methanation.The NiFe catalysts were derived from in-situ grown layered double hydroxides(LDHs)via urea hydrolysis.The influence of different washcoat materials,i.e.,alumina and silica colloidal suspensions on the formation of LDHs layer was investigated,together with the impact of total metal concentration.NiFe LDHs were precipitated on the exterior surface of cordierite washcoated with alumina,while it was found to deposit further inside the channel wall of monolith washcoated with silica due to different intrinsic properties of the colloidal solutions.On the other hand,the thickness of in-situ grown LDHs layers and the catalyst loading could be increased by high metal concentration.The best monolithic catalyst(COR-AluCC-0.5M)was robust,having a thin and well-adhered catalytic layer on the cordierite substrate.As a result,high methane yield was obtained from CO_(2) methanation at high flow rate on this structured NiFe catalysts.The monolithic catalysts appeared as promising structured catalysts for the development of industrial methanation reactor.
基金supported by the Innovation Fund for Technology-based Firms of China(12C26113303061)High Science&Technique Brainstorm Project of Zhejiang Province of China(No.2012C01032-1).
文摘SiC honeycomb ceramics with parallel channels and macroporous walls were prepared by combining extrusion molding with pressureless sintering technology in the presence of starch.The extrusion molding constructed honeycomb structure with parallel channels,while the starch formed spherical macropores on the channel walls.The density and bending strength of SiC honeycomb ceramics decreased with the increase of starch content,while the phase compositions did not vary with the starch content.The control in starch addition could adjust the pore structures on the channel walls of SiC honeycomb ceramics.
基金This work was supported by the National Natural Science Foundation of China(Grant No.50578051).
文摘The ozonation of nitrobenzene in aqueous solu-tion was carried out in a semi-batch reactor to investigate the degradation efficiency,the effect factors,and the reaction mechanism,where honeycomb ceramic was used as a cata-lyst.The presence of honeycomb ceramic could improve the degradation rate of nitrobenzene by 15.46%compared to the results of ozonation alone.Under the conditions of this exper-iment,the degradation rate of honeycomb ceramic-catalyzed ozonation increased by 12.94%with the increase of the amount of catalyst from 1 to 5 blocks.The degradation rates all increased greatly with the increase of temperature and pH of the solution in the processes of honeycomb ceramic-catalyzed ozonation and ozonation alone.But,when the pH of the solution increased to 9.50,the advantage of the honey-comb ceramic-catalyzed ozonation process would be lost.The experimental findings indicated that in the processes of ozonation alone and honeycomb ceramic-catalyzed ozona-tion,nitrobenzene was primarily oxidized by•OH free radical in aqueous solution.The adsorption of nitrobenzene was too limited to have an important influence on the degradation rate of nitrobenzene.With the same total dosage of applied ozone,the multiple step addition of ozone showed much higher removal efficiency than that obtained by one step in the two processes.
基金Project supported by Chongqing Science and Technology Bureau(cstc2018jscx-msybX0057,cstc2020j scx-msxm038)Chongqing Science and Technology Bureau Key Research and Development Project(cstc2018jszxzdyfxmX0018)。
文摘The La-modified Cu-Mn spinel oxide was successfully coated onto honeycomb ceramic by a washcoating method for complete catalytic decomposition of ethyl acetate.The La-modified Cu-Mn oxides were characterized by X-ray diffraction,X-ray fluorescence,H_(2)-temperature programmed reduction,Brunauer-Emmett-Teller method,field-emission scanning electron microscopy and high-resolution transmission electron microscopy.The effects of different precipitants and rare earth doping on the structure and catalytic performance of the catalysts were investigated.The results show that the CuMn_(2)O_(4) spinel with(NH_(4))_(2)CO_(3) as a precipitant can form a larger specific surface area and a suitable pore size,which is beneficial to the absorption of ethyl acetate.Although the rare earth doping does not significantly change the crystal phase structure of the catalyst,it improves its reducibility and lowers the temperature of the catalytic decomposition.With respect to the catalytic decomposition of ethyl acetate,the rare earth-modified Cu-Mn oxide supported on honeycomb ceramic shows excellent catalytic performance with 100% conversion under the conditions of 239℃,space velocity of 12500 h^(-1) and 1000 ppm.And the ethyl acetate removal rate is still 100% after 1440 min of continuous reaction.
基金supported by the National Natural Science Foundation of China(Nos.50802097 and 50832008)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministrythe support of K.C.Wang Education Foundation, Hong Kong
文摘Nanolaminated Ti3AlC2honeycomb monolith with parallel and uniform holes has been prepared through a facile extrusion route by using Ti3AlC2powder as the main raw material.The fabricated honeycomb monolith has high compressive strength of 133 ± 11 and 59 ± 9 MPa,along and perpendicular to the extrusion direction,respectively.It also has good electrical conductivity,and excellent match of thermal expansion coefficient with the washcoat material of γ-AI2O3.These combined properties endow the honeycomb monolith a promising candidate as catalysis substrate for cleaning vehicle exhaust.