Dissertation > Excellent graduate degree dissertation topics show

Preparation, Characterization and Catalytic Activity of Mixed Oxides Catalysts Towards VOCs Combustion

Author: LuZuoFeng
Tutor: LiuHuaZhang
School: Zhejiang University of Technology
Course: Industrial Catalysis
Keywords: Catalytic combustion VOCs mixed oxide Perovskite Cu-Mn-Ce Monolithic catalysts
CLC: O643.36
Type: PhD thesis
Year: 2009
Downloads: 259
Quote: 0
Read: Download Dissertation

Abstract


Volatile Organic Compounds（VOCs） are recognized as major contributors to air pollution besides SOX and NOx.Among many techniques for controlling VOCs emissions,catalytic combustion is one of the most important and promising processes for industrial VOCs elimination due to its low cost,low energy requirement and environmental friendly process.In general,supported noble metal catalysts exhibit high catalytic activities at lower temperatures,and have been widely applied in industrialized VOCs elimination.However,these catalysts are are expensive,sensitive to poisons and easily sintered at high temperature.Therefore,it is necessary to develop non-noble metal catalysts,which are cheap,efficient and stable for VOCs catalytic combustion.In this dissertation,the perovskite and Cu-Mn oxide were studied systematically in following three key issues:（1） Preparation methods of monolithic catalysts.（2） Stability of complex oxides.（3） Reaction mechanism of catalytic combustion of VOCs on mixed oxides catalysts.LaBO3（B=Cr、Mn、Fe、Co、Ni、Cu） perovskite catalysts were prepared by co-precipitation in present dissertion.The present catalysts were characterized by XRD,BET,H2-TPR,O2-TPD and their catalytic performances are studied by total oxidation of benzene,toluene,ethyl acetate and acetone.The results show that catalytic performances of LaBO3 catalysts depend on the nature of oxidation-reduction capacity of B-site ions.LaMnO3 and LaCoO3 have the best catalytic activity among all materials studied.LaCoO3 has anion-deficient perovskites structure which is suitable for catalytic combustion of oxygen-containing organic pollutants such as ethyl acetate and acetone.LaMnO3 has cation-deficient structure which is suitable for the catalytic combustion of organic pollutants with high C-H bond（e.g.benzene）.LaMnO3 has better thermal stability and resistance to chloride poisoning than LaCoO3.The effects of Sr and Au doping on structure and properties of LaMnO3 were also investigated.The results show that the increase of Mn4+ content of Sr-doped catalysts lead to better activity in catalytic combustion of toluene.The improvment of the catalytic activity by doping of precious metal Au are due to enhancing redox of LaMnO3 catalyst.A slurry dip-coating method was used to prepare cordierite honeycomb La0.8Sr0.2MnO3 catalysts coated with Al2O3 and hexaaluminate(HA, Sr0.3Ba0.5La0.2MnAl11O19).It is found that HA coating can reduce the interaction of cordierite support and perovskite at high temperature for La0.8Sr0.2MnO3.Thus solve the deactivation problem of the catalyst at high temperature.The catalytic activities of the powder,wire-mesh honeycomb and ceramic honeycomb La0.8Sr0.2MnO3 catalysts in toluene combustion in fixed bed were studied.The results show that the powder, wire-mesh honeycomb and ceramic honeycomb La0.8Sr0.2MnO3 catalysts show similar catalytic performance.The wire-mesh honeycomb catalyst exhibits better mass transfer and higher thermal response rate,and it is more suitable for treating VOCs at the conditions of large blast volume and big temperature fluctuation than other forms.Cu-Mn catalysts with different Cu/Mn ratio were prepared by combustion method and characterized by XRD,BET,H2-TPR,O2-TPD,and XPS methods.The catalysts were tested in toluene total oxidation at the temperature range of 100-300℃.It is found that Cu1Mn6 catalyst with Cu1.5Mn1.5O4 and Mn3O4 mixed crystalline structure has the best activity.The possible catalytic mechanism was propsed as the followings: Cu1.5Mn1.5O4 with strong oxidation capacity acts as the active center,and the Mn3O4 acts as oxygen supply center.Ce doping can further improve the surface oxygen mobility and catalytic activity of Cu-Mn oxide.Cordierite ceramic honeycomb-type Cu-Mn and Cu-Mn-Ce catalyst were prepared by in-situ combustion synthesis technology.Results show that the proportion of the surface ion on monolithic catalysts was proportional to the ion ratio in dipping solution.Monolithic Cu-Mn and Cu-Mn-Ce catalysts have similar activity trend with powder catalyst.This suggests that cordierite ceramics can not selective adsorb ions in solution,and cordierite carrier has little effect on the intrinsic activities of metal oxides.The catalytic performances of monolithic commercial Pd catalyst,Cu1Mn2Ce4 and La0.8Sr0.2MnO3 were investigated in catalytic combustion of various types of VOCs.The results show that noble metal Pd catalyst is more suitble for catalytic combustion of aromatic VOCs.Mixed Oxide catalyst is more suitable for catalytic combustion of oxygen,nitrogen-containing VOCs and alkanes.In summary, monolithic Cu1Mn2Ce4 catalyst can be used in catalytic combustion of various types of VOCs,which is superior to commercially noble metal Pd catalyst.

Related Dissertations

  1. Adsorption of Volatile Organic Compounds (VOCs) on Metal-Organic Frameworks MIL-101,O647.32
  2. Study on Typical Indoor BTEX Sorption Characteristics and Impact Factors of Wall Paper,X51
  3. Preparation and Photocatalytic Properties of Semiconductor Oxides,O643.36
  4. Preparation and Catalytic Performance of ZrO2-SiO2 Mixed Oxide for THF Polymerization,O631.5
  5. Synthesis, Conducting Properties and Application of Bax Ce0.8Y0.2O3-α + yZnO,TQ174.1
  6. (Class ) perovskite -type oxides catalytic elimination of N 2 O,X701
  7. Synthesis and Characterization of Tio2 -based Nanostructures,TB383.1
  8. Monolith Palladium Catalyst for Purification of Acrylic Acid Emission with High Moisture Content,O643.36
  9. A Study on Emission Characteristics of Volatile Organic Compounds(VOCs)from Enameled Wires Production Process,X511
  10. Source Profile and Chemical Reactivity of Volatile Organic Compounds (VOCs) form Vehicle Exhaust and Paints,X51
  11. Study on DNPH and SSS Modified Polyaniline-based QCM Sensors in Cultural Relics Conservation Micro-environment,TP212
  12. Research of VOCs Gas Detection System for Lung Cancer,R734.2
  13. Engineerings Design of Processing Volatile Organic Compounds by Trickling Biofilter,X701
  14. The Research on Lung Cancer Biomarkers in Exhaled Breath and Clinical Diagnostic Method of E-Nose,R734.2
  15. Enhanced biological trickling filter studies xylene waste gas treatment,X701
  16. The Simulation of Impact of VOCs and NOx from Vehicle Exhausts on Photochemical Oxidants Formation,X51
  17. Automotive interior with modified polypropylene and dissemination of research scratch resistant properties of composite materials,TQ325.14
  18. Gas-Phase Photocatalytic Oxidation of Volatile Organic Compounds with Fluidized-Bed Optical Fibers Reactor,X701
  19. Research on the Activity and Tolerance to Chloride Poisoning of the Perovskite Catalysts for VOCs Catalytic Combustion,O643.36
  20. Study on the NOx Storage and Sulfur Resistance of the Rare-Earth Containing La0.7Sr0.3Co1-xFexO3 Perovskite-type NOx Traps,O643.36
  21. Preparation of Honeycomb Ceramic Perovskite-Type Catalyst and Its Characteristic of Catalytic Combustion of VOCs,O643.36

CLC: > Mathematical sciences and chemical > Chemistry > Physical Chemistry ( theoretical chemistry ),chemical physics > Chemical kinetics,catalysis > Catalytic > Catalyst
© 2012 www.DissertationTopic.Net  Mobile