Fly ash supported Ni―Fe solid acid catalyst for efficient production of diesel additive: intensification through far‐infrared radiation

Abstract

AbstractNovel Ni―Fe solid acid catalyst was prepared through co‐wet impregnation of Fe2 (SO4)3·H2O and Ni (NO3)2·6H2O on fly ash (FA) support. XRD, BET‐BJH, SEM‐EDX, XPS and FTIR methods were employed to characterize the catalyst. The excellent catalyst activity was assessed and optimized in the production of methyl oleate (biodiesel/diesel‐additive). The response surface methodology (RSM) computed optimal parametric values pertaining to maximum oleic acid (OA) conversion (98.37 ± 0.01%) were 15:1 methanol/OA molar ratio, 1:15:2 nickel nitrate: ferric sulphate:FA (wt. ratio) and 4 wt.% (of OA) catalyst concentration in 1 h under conventional heating at mild reaction temperature (60 °C). The optimal catalyst possessed 27.64 m2/g specific surface area and 0.0233 cc/g pore volume with predominantly mesoporous framework. XPS bands confirmed the presence of Fe3+ and mixed Ni2+/Ni3+species rendering an acidity of 5.5 mmol KOH/g. The catalyst comprised of crystalline Fe2O3, Ni2O3 and NiS phases as revealed from XRD analysis. This study also reports the remarkable intensification of esterification reaction through an energy‐efficient application of far‐infrared radiation protocol (1/3rd of conventional power requirement) resulting 99.20% OA conversion in only 10 min at the derived optimal conditions. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.