Optimization of hydrothermal synthesis of pure phase zeolite Na-P1 from South African coal fly ashes

Nicholas M. Musyoka, Leslie F. Petrik, Wilson M. Gitari, Gillian Balfour, Eric Hums

Research output: Journal PublicationArticlepeer-review

54 Citations (Scopus)

Abstract

This study was aimed at optimizing the synthesis conditions for pure phase zeolite Na-P1 from three coal fly ashes obtained from power stations in the Mpumalanga province of South Africa. Synthesis variables evaluated were: hydrothermal treatment time (12-48 hours), temperature (100-160°C) and varying molar quantities of water during the hydrothermal treatment step (H 2O:SiO 2 molar ratio ranged between 0-0.49). The optimum synthesis conditions for preparing pure phase zeolite Na-P1 were achieved when the molar regime was 1 SiO 2: 0.36 Al 2O 3: 0.59 NaOH: 0.49 H 2O and ageing was done at 47C for 48 hours. The optimum hydrothermal treatment time and temperature was 48 hours and 140°C, respectively. Fly ashes sourced from two coal-fired power plants (A, B) were found to produce nearly same high purity zeolite Na-P1 under identical conditions whereas the third fly ash (C) lead to a low quality zeolite Na-P1 under these conditions. The cation exchange capacity for the high pure phase was found to be 4.11 meq/g. These results highlight the fact that adjustment of reactant composition and presynthesis or synthesis parameters, improved quality of zeolite Na-P1 can be achieved and hence an improved potential for application of zeolites prepared from coal fly ash.

Original languageEnglish
Pages (from-to)337-350
Number of pages14
JournalJournal of Environmental Science and Health - Part A Toxic/Hazardous Substances and Environmental Engineering
Volume47
Issue number3
DOIs
Publication statusPublished - 1 Feb 2012
Externally publishedYes

Keywords

  • Zeolite Na-P1
  • ageing step
  • coal fly ash
  • hydrothermal synthesis

ASJC Scopus subject areas

  • Environmental Engineering

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