Transformation of South African coal fly ash into ZSM-5 zeolite and its application as an MTO catalyst

Roland Na M. Missengue, Pit Losch, Grant Sedres, Nicholas M. Musyoka, Ojo O. Fatoba, Benoit Louis, Patrick Pale, Leslie F. Petrik

Research output: Journal PublicationArticlepeer-review

39 Citations (Scopus)


This study presents a way of using South African coal fly ash by extracting metals such as Al and Fe with concentrated sulphuric acid, and then using the solid residue as a feedstock for the synthesis of ZSM-5 zeolite. The percentage of aluminium and iron oxides decreased from 28.0 ± 0.2% and 5.0 ± 0.1% in coal fly ash to 24.6 ± 0.1% and 1.6 ± 0.01% in the acid treated coal fly ash respectively. The fly ash-based zeolite ZSM-5 sample synthesised from the solid residue after extraction of Al and Fe, contained 62% of ZSM-5 zeolite pure phase with a number of Brønsted acid site density of 0.61 mmol per gzeolite. By properly treating the as-prepared coal fly ash-based ZSM-5 zeolite, an active and selective methanol-to-olefins acid catalyst could be designed, leading to full methanol conversion during 15 h on stream. The optimised catalyst exhibited a cumulative methanol conversion capacity of 71 g(MeOHconverted)/g(catalyst) and a light olefin productivity of 21 g(C2=–C4=)/g(catalyst).

Original languageEnglish
Pages (from-to)78-86
Number of pages9
JournalComptes Rendus Chimie
Issue number1
Publication statusPublished - 1 Jan 2017
Externally publishedYes


  • Acid leaching
  • Fly ash
  • Metal extraction
  • MTO catalyst
  • ZSM-5 zeolite

ASJC Scopus subject areas

  • Chemistry (all)
  • Chemical Engineering (all)


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