Effect of Silica-Alumina Ratio and Hydrotherman Ageing on the Adsorption Characteristics of BEA Zeolites for Cold Start Emission Control

N. Burke, D. Trimm, Russell Francis Howe

Research output: Contribution to journalArticle

66 Citations (Scopus)

Abstract

Increasingly stringent legislation has led to the need for better control of vehicle cold start emissions. Research work has identified sodium-BEA zeolite with a silica:alumina ratio of 10 (Na-BEA-silica:alumina = 10) as a potential trapping agent for hydrocarbons during vehicle cold start, with desorption occurring only at about the temperature of operation of a vehicle exhaust catalyst.

Propene and toluene, used as probe molecules for vehicle emissions, were found to absorb under ambient conditions on all forms of BEA. There appear to be two adsorption mechanisms at play, one involving charge gradients in the zeolite framework and characterised by lower desorption temperatures (molecular adsorption) and the other related to zeolite acidity (oligomeric adsorption).

Both the presence of water and simulated ageing reduced the adsorption capacity of the zeolites. Hydrothermal ageing was found to result in dealumination of the zeolite framework, a process that can be reduced by incorporation of lanthanum into the lattice. Water in the gas stream was found to block pores and reduce adsorption. A combination of a more hydrophilic zeolite with BEA zeolite is suggested to overcome the loss in capacity by the presence of water in car exhaust. Crown Copyright (C) 2003 Published by Elsevier B.V. All rights reserved.

Original languageEnglish
Pages (from-to)97-104
Number of pages7
JournalApplied Catalysis A: General
Volume46
DOIs
Publication statusPublished - 2003

Keywords

  • cold start
  • vehicle emissions
  • BEA zeolite
  • trapping
  • adsorption
  • stability
  • silica
  • alumina ratio
  • METHANE ADSORPTION
  • FT-IR
  • TEMPERATURE
  • HYDROCARBON
  • ENGINE
  • HZSM-5
  • BETA

Cite this

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title = "Effect of Silica-Alumina Ratio and Hydrotherman Ageing on the Adsorption Characteristics of BEA Zeolites for Cold Start Emission Control",
abstract = "Increasingly stringent legislation has led to the need for better control of vehicle cold start emissions. Research work has identified sodium-BEA zeolite with a silica:alumina ratio of 10 (Na-BEA-silica:alumina = 10) as a potential trapping agent for hydrocarbons during vehicle cold start, with desorption occurring only at about the temperature of operation of a vehicle exhaust catalyst.Propene and toluene, used as probe molecules for vehicle emissions, were found to absorb under ambient conditions on all forms of BEA. There appear to be two adsorption mechanisms at play, one involving charge gradients in the zeolite framework and characterised by lower desorption temperatures (molecular adsorption) and the other related to zeolite acidity (oligomeric adsorption).Both the presence of water and simulated ageing reduced the adsorption capacity of the zeolites. Hydrothermal ageing was found to result in dealumination of the zeolite framework, a process that can be reduced by incorporation of lanthanum into the lattice. Water in the gas stream was found to block pores and reduce adsorption. A combination of a more hydrophilic zeolite with BEA zeolite is suggested to overcome the loss in capacity by the presence of water in car exhaust. Crown Copyright (C) 2003 Published by Elsevier B.V. All rights reserved.",
keywords = "cold start, vehicle emissions, BEA zeolite, trapping, adsorption, stability, silica, alumina ratio, METHANE ADSORPTION, FT-IR, TEMPERATURE, HYDROCARBON, ENGINE, HZSM-5, BETA",
author = "N. Burke and D. Trimm and Howe, {Russell Francis}",
year = "2003",
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T1 - Effect of Silica-Alumina Ratio and Hydrotherman Ageing on the Adsorption Characteristics of BEA Zeolites for Cold Start Emission Control

AU - Burke, N.

AU - Trimm, D.

AU - Howe, Russell Francis

PY - 2003

Y1 - 2003

N2 - Increasingly stringent legislation has led to the need for better control of vehicle cold start emissions. Research work has identified sodium-BEA zeolite with a silica:alumina ratio of 10 (Na-BEA-silica:alumina = 10) as a potential trapping agent for hydrocarbons during vehicle cold start, with desorption occurring only at about the temperature of operation of a vehicle exhaust catalyst.Propene and toluene, used as probe molecules for vehicle emissions, were found to absorb under ambient conditions on all forms of BEA. There appear to be two adsorption mechanisms at play, one involving charge gradients in the zeolite framework and characterised by lower desorption temperatures (molecular adsorption) and the other related to zeolite acidity (oligomeric adsorption).Both the presence of water and simulated ageing reduced the adsorption capacity of the zeolites. Hydrothermal ageing was found to result in dealumination of the zeolite framework, a process that can be reduced by incorporation of lanthanum into the lattice. Water in the gas stream was found to block pores and reduce adsorption. A combination of a more hydrophilic zeolite with BEA zeolite is suggested to overcome the loss in capacity by the presence of water in car exhaust. Crown Copyright (C) 2003 Published by Elsevier B.V. All rights reserved.

AB - Increasingly stringent legislation has led to the need for better control of vehicle cold start emissions. Research work has identified sodium-BEA zeolite with a silica:alumina ratio of 10 (Na-BEA-silica:alumina = 10) as a potential trapping agent for hydrocarbons during vehicle cold start, with desorption occurring only at about the temperature of operation of a vehicle exhaust catalyst.Propene and toluene, used as probe molecules for vehicle emissions, were found to absorb under ambient conditions on all forms of BEA. There appear to be two adsorption mechanisms at play, one involving charge gradients in the zeolite framework and characterised by lower desorption temperatures (molecular adsorption) and the other related to zeolite acidity (oligomeric adsorption).Both the presence of water and simulated ageing reduced the adsorption capacity of the zeolites. Hydrothermal ageing was found to result in dealumination of the zeolite framework, a process that can be reduced by incorporation of lanthanum into the lattice. Water in the gas stream was found to block pores and reduce adsorption. A combination of a more hydrophilic zeolite with BEA zeolite is suggested to overcome the loss in capacity by the presence of water in car exhaust. Crown Copyright (C) 2003 Published by Elsevier B.V. All rights reserved.

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KW - alumina ratio

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KW - HYDROCARBON

KW - ENGINE

KW - HZSM-5

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