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Assessment the activity of magnetic KOH/Fe3O4@Al2O3 core–shell nanocatalyst in transesterification reaction: effect of Fe/Al ratio on structural and performance

Abstract

Recently, biodiesel production using heterogeneous catalysts has been of great concern. However, simple separation of these catalysts from product mixtures is a problem of the process. In this study, series of magnetic KOH/Fe3O4@Al2O3 core–shell nanocatalysts were synthesized via the incipient wetness impregnation method and the effect of weight ratio of Fe3O4-to-Al2O3 (0.15–0.35) on the catalytic performance was assessed. The samples were characterized by XRD, FTIR, BET-BJH, VSM, SEM, TEM, and EDX analyses and their basicity was measured by the Hammett indicator method. The results revealed that although the magnetic KOH/Fe3O4@Al2O3 nanocatalyst with 25 wt% of Fe3O4 showed less activity as compared to those with 15 wt% of Fe3O4, it exhibited higher surface area and appropriate magnetic properties. The sample presented superparamagnetic properties with the magnetic strength of 1.25 emu/g that was simply recovered by using an external magnetic field. The nanocatalyst converted 98.8% of canola oil to biodiesel under reflux condition at the best operational conditions of 12 M ratio of methanol/oil, 4 wt% of catalyst and 6 h of reaction time. Moreover, the nanocatalyst showed high reusability such that it was reused several times without appreciable loss of its catalytic activity.

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Funding

The authors received financial support from the Ferdowsi University of Mashhad (grant number: 32390) and the Iran Nanotechnology Initiative Council (grant number: 81401).

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Correspondence to Hamed Nayebzadeh.

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Responsible editor: Philippe Garrigues

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Kazemifard, S., Nayebzadeh, H., Saghatoleslami, N. et al. Assessment the activity of magnetic KOH/Fe3O4@Al2O3 core–shell nanocatalyst in transesterification reaction: effect of Fe/Al ratio on structural and performance. Environ Sci Pollut Res 25, 32811–32821 (2018). https://doi.org/10.1007/s11356-018-3249-7

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  • DOI: https://doi.org/10.1007/s11356-018-3249-7

Keywords

  • Core–shell nanoparticle
  • Magnetic nanocatalyst
  • Alumina
  • Biodiesel
  • Transesterification