Inhibiting the agglomeration of molten aluminum particles packed in the binder network is a promising scheme to achieve efficient combustion of solid propellants.In this investigation,the hydroxyl-terminated structure...Inhibiting the agglomeration of molten aluminum particles packed in the binder network is a promising scheme to achieve efficient combustion of solid propellants.In this investigation,the hydroxyl-terminated structured fluorinated alcohol compound(PFD)was introduced to modify the traditional polyethylene glycol/polytetrahydrofuran block copolymerization(HTPE)binder;that is,a unique fluorinated polyether(FTPE)binder was synthesized by embedding fluorinated organic segments into the HTPE binder via crosslinking curing.The FTPE was applied in aluminum-based propellants for the first time.Due to the complete release of fluorinated organic active segments in the range of 300℃to 400℃,the burning rate of FTPEbased propellant increased from 4.07(0%PFD)to 6.36 mm/s(5%PFD),increased by 56.27%under 1 MPa.The reaction heat of FTPE propellants increased from 5.95(0%PFD)to 7.18 MJ/kg(5%PFD)under 3.0 MPa,indicating that HTPE binder modified with PFD would be conducive to inhibiting the D90 of condensed combustion products(CCPs)dropped by 81.84%from 75.46(0%PFD)to 13.71μm(5%PFD)under 3.0 MPa,in consistent with the significant reduction of aluminum agglomerates observed on the quenched burning surface of the propellants.Those results demonstrated that a novel FTPE binder with PFD can release fluorinated organic active segments,which motivate preignition reaction with the alumina shell in the early stage of aluminum combustion,and then enhance the melting diffusion effect of aluminum to inhibit the agglomeration.展开更多
Emissions of volatile organic compounds （VOCs） and carbonyls from residential coal combustion of five coals with different maturities were studied in a simulated room.The coals were burned in form of honeycomb briqu...Emissions of volatile organic compounds （VOCs） and carbonyls from residential coal combustion of five coals with different maturities were studied in a simulated room.The coals were burned in form of honeycomb briquettes in a domestic coal stove,one of the most common fuel/stove combinations in China.Through a dilution system,VOCs and carbonyls samples were collected by canisters and silica-gel cartridges and analyzed by gas chromatography and mass spectrum （GC/MS） and high performance liquid chromatography/ultraviolet （HPLC/UV）,respectively.The results show that the bituminous coals with medium volatile matter content produce the highest emissions while the anthracite yields the lowest.Among the identified carbonyls from the coal smoke,the aromatic compounds （benzaldehyde,2,5-dimethylbenzaldehyde and p-tolualdehyde,m/o-tolualdehyde,benzene,m,p-xylene and trimethyl-benzene） were relatively abundant,which might be due to the molecular structure of the coal.For formaldehyde,aromatic carbonyls and aliphatic alkanes,their concentrations increase up to the maximum values and then decrease with increasing coal maturity.The total carbonyls and VOCs have the same tendency,which was observed for the emission factors of organic carbon （OC）,elemental carbon （EC）,particulate matter （PM） and polycyclic aromatic hydrocarbons （PAHs） detected in the series study.展开更多
Ce0.6Mn0.4O2 catalysts with different sources of manganese and Ce0.6-xZrxMn0.4O2 mixed oxide catalysts were prepared by coprecipitation method and were characterized by N2 adsorption-desorption,TPR,XRD,and XPS techniq...Ce0.6Mn0.4O2 catalysts with different sources of manganese and Ce0.6-xZrxMn0.4O2 mixed oxide catalysts were prepared by coprecipitation method and were characterized by N2 adsorption-desorption,TPR,XRD,and XPS techniques.The activities of the prepared catalysts for ethyl acetate combustion,and the effects of calcination temperature and space velocity on catalytic activity were investigated.The results showed that partial replacement of Mn（NO3）2 with KMnO4 as sources of manganese could improve activities of catalysts.Ce0.45Zr0.15Mn0.4O2 catalyst exhibited the best catalytic activity and high thermal stability,e.g.,T90 could be still below 210℃ even if space velocity was up to 20000h-1.展开更多
Volatile organic compounds are a kind of important indoor and outdoor air pollutants.In recent years,more and more attention has been paid to the ways of volatile organic compound elimination because of its potential ...Volatile organic compounds are a kind of important indoor and outdoor air pollutants.In recent years,more and more attention has been paid to the ways of volatile organic compound elimination because of its potential long-term effects on human health.Among the various available methods for volatile organic compound elimination,the catalytic combustion is the most attractive method due to its high efficiency,low cost,simple operation,and easy scale-up.Perovskite oxides,as a large family of metal oxides with their A-site mainly of lanthanide element and/or alkaline earth metal element and B-site of transition metal element,have been extensively investigated as active and stable catalysts for volatile organic compound removal reactions due to their abundant compositional elements,high thermal/chemical stability,and compositional/structural flexibility.The catalytic performance of perovskite oxides is strongly depended on its material composition,morphology,and surface/bulk properties,while the doping,tailored synthesis route,and composite construction may have a significant effect on the bulk(oxygen vacancy concentration,lattice structure),surface(oxygen species,defect)properties,and particulate morphology,consequently the catalytic activity and stability for volatile organic compound removal.Herein,a comprehensive review about the recent advances in perovskite oxides for volatile organic compound elimination reactions based on catalytic combustion is presented from different aspects with a special emphasis on the material design strategies,such as compositional tuning,morphology control,nanostructure building,hybrid construction,and surface modification.At last,some perspectives are presented on the development and design of perovskite oxide-based catalysts for volatile organic compound removal applications by highlighgting the critical issues and challenges.展开更多
A comprehensive summary for the study on the monitoring of potential carcinogenicpolycyclic aromatic compounds (PACs) in the emission of coal combustion is presented in this pa-per. Some PACs in the stack gases of coa...A comprehensive summary for the study on the monitoring of potential carcinogenicpolycyclic aromatic compounds (PACs) in the emission of coal combustion is presented in this pa-per. Some PACs in the stack gases of coal-fired boiler have been determined with a procedure whichconsists of isokinetic stack sampling, extraction, preseparation and some instrumental analysis stepssuch as gas chromatographylmass spectrometry (GC/MS), high performance liquid chromatographyfHPLC), room temperature phosphorimetry (RTP) and synchronous fluorescence spectroscopy (SFS)and so on. The results indicate that the air pollution of PACs in China are related closely to thecoal combustion.展开更多
This paper presents a comprehensive overview of various advanced technologies employed in the treatment of volatile organic compounds(VOCs),which are crucial pollutants in industrial emissions.The study explores diffe...This paper presents a comprehensive overview of various advanced technologies employed in the treatment of volatile organic compounds(VOCs),which are crucial pollutants in industrial emissions.The study explores different methods,including direct combustion,thermal combustion,catalytic combustion,low-temperature plasma purification,photocatalytic purification,membrane separation,and adsorption methods.Each technology is critically analyzed for its operational principles,efficiency,and applicability under different conditions.Special attention is given to adsorption concentration and catalytic combustion parallel method,highlighting its efficiency in treating low-concentration,high-volume VOC emissions.The paper also delves into the advantages and limitations of each method,providing insights into their effectiveness in various industrial scenarios.The study aims to offer a detailed guide for selecting appropriate VOC treatment technologies,contributing to enhanced environmental protection and sustainable industrial practices.展开更多
Two novel washcoats Ce0.8Zr0.15La0.05Oδ and Ce0.8Zr0.2O2 was prepared by an impregnation method, which acted as a host for the active Pd component to prepare Pd/Ce0.8Zr0.15La0.05Oδ/substrate and Pd/Ce0.8Zr0.2O2/subs...Two novel washcoats Ce0.8Zr0.15La0.05Oδ and Ce0.8Zr0.2O2 was prepared by an impregnation method, which acted as a host for the active Pd component to prepare Pd/Ce0.8Zr0.15La0.05Oδ/substrate and Pd/Ce0.8Zr0.2O2/substrate monolithic catalysts for toluene combustion. The washcoats was characterized by X-ray diffraction (XRD), Raman spectroscopy, Brunauner-Emmett-Teller (BET), and H2-temperature-programmed reduction (H2-TPR). The result indicated that both the washcoats had strong vibration-shock resistance according to ultrasonic test. Doping La3+ into CeO2-ZrO2 solid solution could generate more oxygen vacancies, and could inhibit the sinter of CeO2-ZrO2 solid solution when calcined at high temperatures (800, 900 and 1000 °C). The washcoat Ce0.8Zr0.15La0.05Oδ had much better redox properties. The reductive temperature of Ce4+ species shifted to low temperature by 60 °C when the washcoats calcined at high temperatures (800, 900 and 1000 °C). The Pd/Ce0.8Zr0.15La0.05Oδ/substrate monolithic catalyst calcination at 500 °C had the best catalytic activity and the 95% toluene conversion at a temperature as low as 190 °C. When calcined at low temperature (500 and 700 °C), the catalytic activity has little improvement, however, when calcined at high temperature, the catalytic activity of Pd/Ce0.8Zr0.15La0.05Oδ/substrate monolithic catalysts had significant improvement. As catalyst washcoat, the Ce0.8Zr0.15La0.05Oδ had better thermal stability than the washcoat Ce0.8Zr0.2O2, the developed Pd/Ce0.8Zr0.15La0.05Oδ/ substrate monolithic catalyst in this work was promising for eliminating Volatile organic compounds.展开更多
The research investigated the effect of doping two metals separately or together into Ce0.5Zr0.5O2 on the catalytic activity of MnOx/Ce0.5-xZr0.5-xM0.2xOy/Al2O3 （M=Y, Mn, Y and Mn） for catalytic combustion of benzen...The research investigated the effect of doping two metals separately or together into Ce0.5Zr0.5O2 on the catalytic activity of MnOx/Ce0.5-xZr0.5-xM0.2xOy/Al2O3 （M=Y, Mn, Y and Mn） for catalytic combustion of benzene. The prepared catalysts were characterized by X-ray diffraction （XRD）, surface area analysis, oxygen storage capacity （OSC）, and H2-temperature programmed reduction （H2-TPR）. Catalytic test was performed on a conventional fixed bed flow reactor. The characterization results revealed that Y and Mn ions entered into the ceria-zirconia mixed oxides framework, which improved the textural properties and greatly promoted the MnOx dispersion on the support surface. The complete conversion temperature of benzene on MnOx/Ce0.4Zr0.4Y0.1Mn0.1Oy/Al2O3 was 563 K, and the selectivity of carbon dioxides was 99%. This catalyst could be applied in a wide range of GHSV and wide concentration condition, showing great potential for application.展开更多
Discussed latest research results of basic theory research of coal spontaneous combustion in detail,with quantum chemical theory and method and experiment syste- matically studied chemical structure of coal molecule,a...Discussed latest research results of basic theory research of coal spontaneous combustion in detail,with quantum chemical theory and method and experiment syste- matically studied chemical structure of coal molecule,adsorption mechanism of coal sur- face to oxygen molecule and chemical reaction mechanism and process of spontaneous combustion of organic macromolecule and low molecular weight compound in coal from microcosmic view,and established complete theoretical system of the mechanism of coal spontaneous combustion.展开更多
La-hexaaluminate catalyst for methane catalytic combustion was synthesized by a reverse microemulsion. Pseudo-temary phase diagrams of a quaternary microemulsion system of sodium dodecyl sulfate （SDS）, n-pentanol, n...La-hexaaluminate catalyst for methane catalytic combustion was synthesized by a reverse microemulsion. Pseudo-temary phase diagrams of a quaternary microemulsion system of sodium dodecyl sulfate （SDS）, n-pentanol, n-octane, and water （or Al（NO3）3 solution） were presented. The effects of alcohol chain length, cosurfactant-to-surfaqtant rat!0, and salt concentration on the formation and stability of the microemul- sion system were studied. The phenomenon that the conductivity changed with water supported the phase behavior of the microemulsion system. La（MnffFex）Al12_xO19_a catalysts, applied in methane combustion and with high-temperature stability, were synthesized within the stable areas of the phase diagram of the microemulsion system, when SDS was chosen as surfactant, n-pentanol as cosurfactant, and n-octane as oil phase. The physical properties and structure of the catalysts were characterized by BET method, transmission electron microscope （TEM）, and X-ray diffraction （XRD）. A micro-fixed-bed reactor was used to measure the catalytic activity of hexaaluminates in methane combustion. The results show that the reverse microemulsions can be used to produce discrete La-hexaaluminate nanoparticles that display excellent methane combustion activity owing to their high surface area and high thermal stability.展开更多
We focused on the surface reinforcement of ligth weight casting alloys with Ni-AI intermetallic compounds by in-situ combustion reaction to improve the surface properties of non-ferrous casting components.In our previ...We focused on the surface reinforcement of ligth weight casting alloys with Ni-AI intermetallic compounds by in-situ combustion reaction to improve the surface properties of non-ferrous casting components.In our previous works,green compact of elemental Ni and Al powders were reacted to form Ni-3Al intermetallic compound by SHS （Self-propagating high temperature synthesis） reaction with the heat of molten Al alloy and simultaneously bonded with Al casting alloy.But some defects such as tiny cracks and porosities were remained in the reacted compact.So we applied pressure to prevent thermal cracks and fill up the pores with liquid Al alloy by squeeze casting process.The compressed Al alloy bonded with the Ni-3Al intermetallic compound was sectioned and observed by optical microscopy and scanning electron microscopy （SEM）.The stoichiometric compositions of the intermetallics formed around the bonded interface and in the reacted compact were identified by energy dispersive spectroscopy （EDS） and electron probe micro analysis （EPMA）. Si rich layer was formed on the Al alloy side near the bonded interface by the sequential solidification of Al alloy.The porosities observed in the reacted Ni-3Al compact were filled up with the liquid AI alloy.The Si particles from the molten Al alloy were detected in the pores of reacted Ni-3Al intermetallic compact.The Al casting alloy and Ni-3Al intermetallic compound were joined very soundly by applying pressure to the liquid Al alloy.展开更多
A Ce0.4Zr0.6O2 washcoat was prepared using an impregnation method, which acted as a host for the active Pd component to prepare a Pd-Ce0.4Zr0.6O2/substrate monolithic catalyst for toluene combustion. The catalyst was ...A Ce0.4Zr0.6O2 washcoat was prepared using an impregnation method, which acted as a host for the active Pd component to prepare a Pd-Ce0.4Zr0.6O2/substrate monolithic catalyst for toluene combustion. The catalyst was characterized by scanning electron microscopy （SEM）, Raman spectroscopy, Brunauner-Emmett-Teller （BET）, and carbon monoxide tonperature-programmed reduction （CO-TPR）. It was found that the washcoat had strong vibration-shock resistance according to an ultrasonic test. The Pd-Ce0.4Zr0.6O2/substrate monolithic catalyst calcined at 400 ℃ showed 95% toluene conversion at a temperature as low as 210 ℃. Furthermore, the lowest temperature for 95% toluene conversion was increased by 40℃ after the catalyst calcined at 900℃, indicating that the catalyst had good thermal stability. The results revealed that the developed catalyst in this study was promising for eliminating volatile organic compounds （VOCs）.展开更多
CuOγ-Al2O3 catalysts were prepared by plasma treatment and conventional impregnation methods. The catalytic combustion of two kinds of volatile organic compounds (VOCs), toluene and benzene, were carried out over the...CuOγ-Al2O3 catalysts were prepared by plasma treatment and conventional impregnation methods. The catalytic combustion of two kinds of volatile organic compounds (VOCs), toluene and benzene, were carried out over these CuOγ-Al2O3 catalysts. The surface properties of these catalysts were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The experimental results showed that in catalytic combustion the activity of the CuOγ-Al2O3 catalyst prepared via plasma was much higher than that of the CuOγ-Al2O3 catalyst prepared by conventional impregnation method. XRD results showed that an enhanced dispersion had been achieved with the plasma treatment. SEM results indicated that the size became much smaller and the surface became more uniform with the plasma treatment.展开更多
Volatile organic compounds（VOCs） are a major component in air pollutants and pose great risks to both human health and environmental protection. Currently, VOC abatement in industrial applications is through the use...Volatile organic compounds（VOCs） are a major component in air pollutants and pose great risks to both human health and environmental protection. Currently, VOC abatement in industrial applications is through the use of activated carbons as adsorbents and oxide-supported metals as catalysts. Notably, activated carbons easily adsorb water, which strongly hinders the adsorption of VOCs; conventional oxides typically possess relatively low surface areas and random pores, which effectively influence the catalytic conversion of VOCs. Zeolites, in contrast with activated carbons and oxides, can be designed to have very uniform and controllable micropores, in addition to tailored wettability properties, which can favor the selective adsorption of VOCs. In particular, zeolites with selective adsorptive properties when combined with catalytically active metals result in zeolite-supported metals exhibiting significantly improved performance in the catalytic combustion of VOCs compared with conventional oxide-supported catalysts. In this review, recent developments on VOC abatement by adsorptive and catalytic techniques over zeolite-based materials have been briefly summarized.展开更多
Most of volatile organic compounds （VOCs） are harmful to the atmosphere and human health. Cata‐lytic combustion is an effective way to eliminate VOCs. The key issue is the availability of high per‐formance catalys...Most of volatile organic compounds （VOCs） are harmful to the atmosphere and human health. Cata‐lytic combustion is an effective way to eliminate VOCs. The key issue is the availability of high per‐formance catalysts. Many catalysts including transition metal oxides, mixed metal oxides, and sup‐ported noble metals have been developed. Among these catalysts, the porous ones attract much attention. In this review, we focus on recent advances in the synthesis of ordered mesoporous and macroporous transition metal oxides, perovskites, and supported noble metal catalysts and their catalytic oxidation of VOCs. The porous catalysts outperformed their bulk counterparts. This excel‐lent catalytic performance was due to their high surface areas, high concentration of adsorbed oxy‐gen species, low temperature reducibility, strong interaction between noble metal and support and highly dispersed noble metal nanoparticles and unique porous structures. Catalytic oxidation of carbon monoxide over typical catalysts was also discussed. We made conclusive remarks and pro‐posed future work for the removal of VOCs.展开更多
Benzene is a typical component of volatile organic compounds(VOCs)in the iron ore sintering flue gas.The combustion behavior of benzene directly affects the emission of VOCs in iron ore sintering process.The effects o...Benzene is a typical component of volatile organic compounds(VOCs)in the iron ore sintering flue gas.The combustion behavior of benzene directly affects the emission of VOCs in iron ore sintering process.The effects of temperature,benzene,and oxygen concentrations on the conversion ratio of benzene were investigated by experiments and numerical simulation.The experiments were carried out in a tube reactor at temperatures of 773-1098 K,benzene concentrations of 0.01-0.03 vol.%,and oxygen concentrations of 10-21 vol.%.The numerical simulation was performed with the plug flow model in the CHEMKIN program based on a kinetic model that consists of 132 chemical species and 772 elementary step-like reactions.The experimental results reveal that increasing the temperature and benzene concentration could signifi-cantly promote benzene combustion.It is attributed to the increase in the reaction rates of all steps in the pathway for forming CO_(2)and H_(2)O.In addition,due to the large equivalent ratio of oxygen to benzene,the conversion ratio of benzene remained constant at different oxygen concentrations.The simulation results were in good agreement with the experimental results and indicated that six elementary reactions dominated the formations of CO_(2)and H_(2)O.The oxidations of C_(6)H_(5)O,CO,and C_(5)H_(4)O intermediates to CO_(2)were the limiting steps in the reaction pathways.展开更多
基金Fundamental Research Funds for the Central Universities,Grant/Award Number:3052017010。
文摘Inhibiting the agglomeration of molten aluminum particles packed in the binder network is a promising scheme to achieve efficient combustion of solid propellants.In this investigation,the hydroxyl-terminated structured fluorinated alcohol compound(PFD)was introduced to modify the traditional polyethylene glycol/polytetrahydrofuran block copolymerization(HTPE)binder;that is,a unique fluorinated polyether(FTPE)binder was synthesized by embedding fluorinated organic segments into the HTPE binder via crosslinking curing.The FTPE was applied in aluminum-based propellants for the first time.Due to the complete release of fluorinated organic active segments in the range of 300℃to 400℃,the burning rate of FTPEbased propellant increased from 4.07(0%PFD)to 6.36 mm/s(5%PFD),increased by 56.27%under 1 MPa.The reaction heat of FTPE propellants increased from 5.95(0%PFD)to 7.18 MJ/kg(5%PFD)under 3.0 MPa,indicating that HTPE binder modified with PFD would be conducive to inhibiting the D90 of condensed combustion products(CCPs)dropped by 81.84%from 75.46(0%PFD)to 13.71μm(5%PFD)under 3.0 MPa,in consistent with the significant reduction of aluminum agglomerates observed on the quenched burning surface of the propellants.Those results demonstrated that a novel FTPE binder with PFD can release fluorinated organic active segments,which motivate preignition reaction with the alumina shell in the early stage of aluminum combustion,and then enhance the melting diffusion effect of aluminum to inhibit the agglomeration.
基金supported by the National Natural Science Foundation of China (Grant Nos.40773047,40605033 and 40973071)the Shanghai Leading Academic Discipline Project (Grant No.S30109)the Earmarked Foundation of the State Key Laboratory of Organic Geochemistry (Grant No.OGL-200705)
文摘Emissions of volatile organic compounds （VOCs） and carbonyls from residential coal combustion of five coals with different maturities were studied in a simulated room.The coals were burned in form of honeycomb briquettes in a domestic coal stove,one of the most common fuel/stove combinations in China.Through a dilution system,VOCs and carbonyls samples were collected by canisters and silica-gel cartridges and analyzed by gas chromatography and mass spectrum （GC/MS） and high performance liquid chromatography/ultraviolet （HPLC/UV）,respectively.The results show that the bituminous coals with medium volatile matter content produce the highest emissions while the anthracite yields the lowest.Among the identified carbonyls from the coal smoke,the aromatic compounds （benzaldehyde,2,5-dimethylbenzaldehyde and p-tolualdehyde,m/o-tolualdehyde,benzene,m,p-xylene and trimethyl-benzene） were relatively abundant,which might be due to the molecular structure of the coal.For formaldehyde,aromatic carbonyls and aliphatic alkanes,their concentrations increase up to the maximum values and then decrease with increasing coal maturity.The total carbonyls and VOCs have the same tendency,which was observed for the emission factors of organic carbon （OC）,elemental carbon （EC）,particulate matter （PM） and polycyclic aromatic hydrocarbons （PAHs） detected in the series study.
基金supported by the National Natural Science Foundation of China (No. 20773090)the National High Technology Research and Development Program of China (863 Program,No. 2006AA06Z347)the Youth Fund of Sichuan University (No. 2008119)
文摘Ce0.6Mn0.4O2 catalysts with different sources of manganese and Ce0.6-xZrxMn0.4O2 mixed oxide catalysts were prepared by coprecipitation method and were characterized by N2 adsorption-desorption,TPR,XRD,and XPS techniques.The activities of the prepared catalysts for ethyl acetate combustion,and the effects of calcination temperature and space velocity on catalytic activity were investigated.The results showed that partial replacement of Mn（NO3）2 with KMnO4 as sources of manganese could improve activities of catalysts.Ce0.45Zr0.15Mn0.4O2 catalyst exhibited the best catalytic activity and high thermal stability,e.g.,T90 could be still below 210℃ even if space velocity was up to 20000h-1.
基金supported by the National Natural Science Foundation of China(Project No.21908106 and 21878158)the Jiangsu Natural Science Foundation(Project No.BK20190682)+2 种基金the Program for Jiangsu Specially Appointed Professorsthe Funding from State Key Laboratory of Materials-Oriented Chemical Engineering(Project No.ZK201808)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Volatile organic compounds are a kind of important indoor and outdoor air pollutants.In recent years,more and more attention has been paid to the ways of volatile organic compound elimination because of its potential long-term effects on human health.Among the various available methods for volatile organic compound elimination,the catalytic combustion is the most attractive method due to its high efficiency,low cost,simple operation,and easy scale-up.Perovskite oxides,as a large family of metal oxides with their A-site mainly of lanthanide element and/or alkaline earth metal element and B-site of transition metal element,have been extensively investigated as active and stable catalysts for volatile organic compound removal reactions due to their abundant compositional elements,high thermal/chemical stability,and compositional/structural flexibility.The catalytic performance of perovskite oxides is strongly depended on its material composition,morphology,and surface/bulk properties,while the doping,tailored synthesis route,and composite construction may have a significant effect on the bulk(oxygen vacancy concentration,lattice structure),surface(oxygen species,defect)properties,and particulate morphology,consequently the catalytic activity and stability for volatile organic compound removal.Herein,a comprehensive review about the recent advances in perovskite oxides for volatile organic compound elimination reactions based on catalytic combustion is presented from different aspects with a special emphasis on the material design strategies,such as compositional tuning,morphology control,nanostructure building,hybrid construction,and surface modification.At last,some perspectives are presented on the development and design of perovskite oxide-based catalysts for volatile organic compound removal applications by highlighgting the critical issues and challenges.
文摘A comprehensive summary for the study on the monitoring of potential carcinogenicpolycyclic aromatic compounds (PACs) in the emission of coal combustion is presented in this pa-per. Some PACs in the stack gases of coal-fired boiler have been determined with a procedure whichconsists of isokinetic stack sampling, extraction, preseparation and some instrumental analysis stepssuch as gas chromatographylmass spectrometry (GC/MS), high performance liquid chromatographyfHPLC), room temperature phosphorimetry (RTP) and synchronous fluorescence spectroscopy (SFS)and so on. The results indicate that the air pollution of PACs in China are related closely to thecoal combustion.
文摘This paper presents a comprehensive overview of various advanced technologies employed in the treatment of volatile organic compounds(VOCs),which are crucial pollutants in industrial emissions.The study explores different methods,including direct combustion,thermal combustion,catalytic combustion,low-temperature plasma purification,photocatalytic purification,membrane separation,and adsorption methods.Each technology is critically analyzed for its operational principles,efficiency,and applicability under different conditions.Special attention is given to adsorption concentration and catalytic combustion parallel method,highlighting its efficiency in treating low-concentration,high-volume VOC emissions.The paper also delves into the advantages and limitations of each method,providing insights into their effectiveness in various industrial scenarios.The study aims to offer a detailed guide for selecting appropriate VOC treatment technologies,contributing to enhanced environmental protection and sustainable industrial practices.
基金Project supported by Zhejiang Provincial Natural Science Foundation of China (203147)the National Natural Science Foundation of China (20473075)
文摘Two novel washcoats Ce0.8Zr0.15La0.05Oδ and Ce0.8Zr0.2O2 was prepared by an impregnation method, which acted as a host for the active Pd component to prepare Pd/Ce0.8Zr0.15La0.05Oδ/substrate and Pd/Ce0.8Zr0.2O2/substrate monolithic catalysts for toluene combustion. The washcoats was characterized by X-ray diffraction (XRD), Raman spectroscopy, Brunauner-Emmett-Teller (BET), and H2-temperature-programmed reduction (H2-TPR). The result indicated that both the washcoats had strong vibration-shock resistance according to ultrasonic test. Doping La3+ into CeO2-ZrO2 solid solution could generate more oxygen vacancies, and could inhibit the sinter of CeO2-ZrO2 solid solution when calcined at high temperatures (800, 900 and 1000 °C). The washcoat Ce0.8Zr0.15La0.05Oδ had much better redox properties. The reductive temperature of Ce4+ species shifted to low temperature by 60 °C when the washcoats calcined at high temperatures (800, 900 and 1000 °C). The Pd/Ce0.8Zr0.15La0.05Oδ/substrate monolithic catalyst calcination at 500 °C had the best catalytic activity and the 95% toluene conversion at a temperature as low as 190 °C. When calcined at low temperature (500 and 700 °C), the catalytic activity has little improvement, however, when calcined at high temperature, the catalytic activity of Pd/Ce0.8Zr0.15La0.05Oδ/substrate monolithic catalysts had significant improvement. As catalyst washcoat, the Ce0.8Zr0.15La0.05Oδ had better thermal stability than the washcoat Ce0.8Zr0.2O2, the developed Pd/Ce0.8Zr0.15La0.05Oδ/ substrate monolithic catalyst in this work was promising for eliminating Volatile organic compounds.
基金supported by the National Natural Science Foundation of China (20773090)the National Natural Science Key Foundation of China (2033030)
文摘The research investigated the effect of doping two metals separately or together into Ce0.5Zr0.5O2 on the catalytic activity of MnOx/Ce0.5-xZr0.5-xM0.2xOy/Al2O3 （M=Y, Mn, Y and Mn） for catalytic combustion of benzene. The prepared catalysts were characterized by X-ray diffraction （XRD）, surface area analysis, oxygen storage capacity （OSC）, and H2-temperature programmed reduction （H2-TPR）. Catalytic test was performed on a conventional fixed bed flow reactor. The characterization results revealed that Y and Mn ions entered into the ceria-zirconia mixed oxides framework, which improved the textural properties and greatly promoted the MnOx dispersion on the support surface. The complete conversion temperature of benzene on MnOx/Ce0.4Zr0.4Y0.1Mn0.1Oy/Al2O3 was 563 K, and the selectivity of carbon dioxides was 99%. This catalyst could be applied in a wide range of GHSV and wide concentration condition, showing great potential for application.
基金National Natural Science Foundation(50474010)Eleventh Five Year Key Technologies(2006BAK03B05)
文摘Discussed latest research results of basic theory research of coal spontaneous combustion in detail,with quantum chemical theory and method and experiment syste- matically studied chemical structure of coal molecule,adsorption mechanism of coal sur- face to oxygen molecule and chemical reaction mechanism and process of spontaneous combustion of organic macromolecule and low molecular weight compound in coal from microcosmic view,and established complete theoretical system of the mechanism of coal spontaneous combustion.
基金supported by the National Natural Science Foundation of China (No. 20706004)the Beijing Natural Science Foundation (No. 8092022)
文摘La-hexaaluminate catalyst for methane catalytic combustion was synthesized by a reverse microemulsion. Pseudo-temary phase diagrams of a quaternary microemulsion system of sodium dodecyl sulfate （SDS）, n-pentanol, n-octane, and water （or Al（NO3）3 solution） were presented. The effects of alcohol chain length, cosurfactant-to-surfaqtant rat!0, and salt concentration on the formation and stability of the microemul- sion system were studied. The phenomenon that the conductivity changed with water supported the phase behavior of the microemulsion system. La（MnffFex）Al12_xO19_a catalysts, applied in methane combustion and with high-temperature stability, were synthesized within the stable areas of the phase diagram of the microemulsion system, when SDS was chosen as surfactant, n-pentanol as cosurfactant, and n-octane as oil phase. The physical properties and structure of the catalysts were characterized by BET method, transmission electron microscope （TEM）, and X-ray diffraction （XRD）. A micro-fixed-bed reactor was used to measure the catalytic activity of hexaaluminates in methane combustion. The results show that the reverse microemulsions can be used to produce discrete La-hexaaluminate nanoparticles that display excellent methane combustion activity owing to their high surface area and high thermal stability.
文摘We focused on the surface reinforcement of ligth weight casting alloys with Ni-AI intermetallic compounds by in-situ combustion reaction to improve the surface properties of non-ferrous casting components.In our previous works,green compact of elemental Ni and Al powders were reacted to form Ni-3Al intermetallic compound by SHS （Self-propagating high temperature synthesis） reaction with the heat of molten Al alloy and simultaneously bonded with Al casting alloy.But some defects such as tiny cracks and porosities were remained in the reacted compact.So we applied pressure to prevent thermal cracks and fill up the pores with liquid Al alloy by squeeze casting process.The compressed Al alloy bonded with the Ni-3Al intermetallic compound was sectioned and observed by optical microscopy and scanning electron microscopy （SEM）.The stoichiometric compositions of the intermetallics formed around the bonded interface and in the reacted compact were identified by energy dispersive spectroscopy （EDS） and electron probe micro analysis （EPMA）. Si rich layer was formed on the Al alloy side near the bonded interface by the sequential solidification of Al alloy.The porosities observed in the reacted Ni-3Al compact were filled up with the liquid AI alloy.The Si particles from the molten Al alloy were detected in the pores of reacted Ni-3Al intermetallic compact.The Al casting alloy and Ni-3Al intermetallic compound were joined very soundly by applying pressure to the liquid Al alloy.
基金Project supported by Zhejiang Provincial Nature Science Foundation of China (203147)the National Natural ScienceFoundation of China (20473075)
文摘A Ce0.4Zr0.6O2 washcoat was prepared using an impregnation method, which acted as a host for the active Pd component to prepare a Pd-Ce0.4Zr0.6O2/substrate monolithic catalyst for toluene combustion. The catalyst was characterized by scanning electron microscopy （SEM）, Raman spectroscopy, Brunauner-Emmett-Teller （BET）, and carbon monoxide tonperature-programmed reduction （CO-TPR）. It was found that the washcoat had strong vibration-shock resistance according to an ultrasonic test. The Pd-Ce0.4Zr0.6O2/substrate monolithic catalyst calcined at 400 ℃ showed 95% toluene conversion at a temperature as low as 210 ℃. Furthermore, the lowest temperature for 95% toluene conversion was increased by 40℃ after the catalyst calcined at 900℃, indicating that the catalyst had good thermal stability. The results revealed that the developed catalyst in this study was promising for eliminating volatile organic compounds （VOCs）.
基金The national Natural Science Foundation of China (No. 20336020) the Doctorate Foundation of the State Education Ministry of China (No.20020561010) The Natural Science Foundation of Guangdong Province of China (No.36566).
文摘CuOγ-Al2O3 catalysts were prepared by plasma treatment and conventional impregnation methods. The catalytic combustion of two kinds of volatile organic compounds (VOCs), toluene and benzene, were carried out over these CuOγ-Al2O3 catalysts. The surface properties of these catalysts were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The experimental results showed that in catalytic combustion the activity of the CuOγ-Al2O3 catalyst prepared via plasma was much higher than that of the CuOγ-Al2O3 catalyst prepared by conventional impregnation method. XRD results showed that an enhanced dispersion had been achieved with the plasma treatment. SEM results indicated that the size became much smaller and the surface became more uniform with the plasma treatment.
基金the framework of the China-Greece joint research andtechnology programmes 2000-2002(Project title:‘Investigation on the characteristics of forest fires in the early stage andits control technique National Natural Science Foundation of China under Grants 50346038 , 50320120156,the China NK-BRSF project(No.2001CB409600)the Anhui Ex-cellent Youth Scientist Fundation(2001-2002),and the National Key Technologies R&D Programme(2001BA510B09-03).
基金supported by the Fundamental Research Funds for the Central Universities(2015XZZX004-04)Zhejiang Provincial Natural Science Foundation(LR15B030001)~~
文摘Volatile organic compounds（VOCs） are a major component in air pollutants and pose great risks to both human health and environmental protection. Currently, VOC abatement in industrial applications is through the use of activated carbons as adsorbents and oxide-supported metals as catalysts. Notably, activated carbons easily adsorb water, which strongly hinders the adsorption of VOCs; conventional oxides typically possess relatively low surface areas and random pores, which effectively influence the catalytic conversion of VOCs. Zeolites, in contrast with activated carbons and oxides, can be designed to have very uniform and controllable micropores, in addition to tailored wettability properties, which can favor the selective adsorption of VOCs. In particular, zeolites with selective adsorptive properties when combined with catalytically active metals result in zeolite-supported metals exhibiting significantly improved performance in the catalytic combustion of VOCs compared with conventional oxide-supported catalysts. In this review, recent developments on VOC abatement by adsorptive and catalytic techniques over zeolite-based materials have been briefly summarized.
基金supported by the National High Technology Research and Development Program (863 Program,2015AA034603)the National Natural Science Foundation of China (21377008,201077007,20973017)+1 种基金Foundation on the Creative Research Team Construction Promotion Project of Beijing Municipal InstitutionsScientific Research Base Construction-Science and Technology Creation Platform National Materials Research Base Construction~~
文摘Most of volatile organic compounds （VOCs） are harmful to the atmosphere and human health. Cata‐lytic combustion is an effective way to eliminate VOCs. The key issue is the availability of high per‐formance catalysts. Many catalysts including transition metal oxides, mixed metal oxides, and sup‐ported noble metals have been developed. Among these catalysts, the porous ones attract much attention. In this review, we focus on recent advances in the synthesis of ordered mesoporous and macroporous transition metal oxides, perovskites, and supported noble metal catalysts and their catalytic oxidation of VOCs. The porous catalysts outperformed their bulk counterparts. This excel‐lent catalytic performance was due to their high surface areas, high concentration of adsorbed oxy‐gen species, low temperature reducibility, strong interaction between noble metal and support and highly dispersed noble metal nanoparticles and unique porous structures. Catalytic oxidation of carbon monoxide over typical catalysts was also discussed. We made conclusive remarks and pro‐posed future work for the removal of VOCs.
基金This work was supported by the National Natural Science Foundation of China(Nos.51904127 and 51166004)Key R&D Program of Jiangxi Province(Nos.20202BBGL73117 and 20201BBE51013)+2 种基金Nanchang Key Laboratory(No.2021-NCZDSY-020)Pilot Demonstration Project for the Contract Responsibility System of the Provincial Science and Technology Plan Project of Jiangxi Academy of Sciences(Nos.2021YSBG21015,2022YSBG50010 and 2023YSTZX02)Open Project of Jiangxi Zhongke Ecological Civilization Innovation Research Institute(No.JXZK-2020-01).
文摘Benzene is a typical component of volatile organic compounds(VOCs)in the iron ore sintering flue gas.The combustion behavior of benzene directly affects the emission of VOCs in iron ore sintering process.The effects of temperature,benzene,and oxygen concentrations on the conversion ratio of benzene were investigated by experiments and numerical simulation.The experiments were carried out in a tube reactor at temperatures of 773-1098 K,benzene concentrations of 0.01-0.03 vol.%,and oxygen concentrations of 10-21 vol.%.The numerical simulation was performed with the plug flow model in the CHEMKIN program based on a kinetic model that consists of 132 chemical species and 772 elementary step-like reactions.The experimental results reveal that increasing the temperature and benzene concentration could signifi-cantly promote benzene combustion.It is attributed to the increase in the reaction rates of all steps in the pathway for forming CO_(2)and H_(2)O.In addition,due to the large equivalent ratio of oxygen to benzene,the conversion ratio of benzene remained constant at different oxygen concentrations.The simulation results were in good agreement with the experimental results and indicated that six elementary reactions dominated the formations of CO_(2)and H_(2)O.The oxidations of C_(6)H_(5)O,CO,and C_(5)H_(4)O intermediates to CO_(2)were the limiting steps in the reaction pathways.
