The catalytic cracking of sterically challenging plastic feedstocks over high acid density Al-SBA-15 catalysts

Joseph Socci, Amin Osatiashtiani, Georgios Kyriakou, Tony Bridgwater

Research output: Contribution to journalArticle

Abstract

The catalytic cracking of polyolefinic waste materials over solid acid catalysts, such as zeolites, is a promising process for the production of useful fuels and chemicals. However, the inherent diffusional constraints of the microporous zeolites restrict the access of bulky polyolefin molecules to the active site, therefore limiting their effectiveness. To address this, a simple yet effective method of producing mesoporous Al-SBA-15 materials with a high density of Brønsted acid sites has been employed. These catalysts are shown to be very active for the catalytic cracking of low density polyethylene (LDPE), a common waste plastic. The acidic and textural properties of the catalysts were characterised by ICP-OES, XPS, XRD, N2 physisorption, propylamine-TPD, pyridine-FTIR and STEM and have been correlated with their catalytic activity. The product distribution from the catalytic cracking of LDPE has been shown to depend strongly on both the pore architecture and the Al content of the SBA-15 and thus the density and strength of Brønsted acid sites. Fine-tuning the Al content of the SBA-15 materials can direct the product distribution of the hydrocarbons. The Al-SBA-15 materials display increased cracking orientated towards aliphatic hydrocarbons compared to ZSM-5, attributed to the mesoporous nature of SBA-15, overcoming diffusional limitations.
Original languageEnglish
Pages (from-to)218-227
Number of pages10
JournalApplied Catalysis A: General
Volume570
Early online date24 Nov 2018
DOIs
Publication statusPublished - 25 Jan 2019

Bibliographical note

© 2018, Elsevier. Licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International http://creativecommons.org/licenses/by-nc-nd/4.0/

Keywords

  • Al-SBA-15
  • Catalytic cracking
  • LDPE
  • Mesoporous materials
  • Pyrolysis

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