SCI和EI收录∣中国化工学会会刊

Chin.J.Chem.Eng. ›› 2015, Vol. 23 ›› Issue (1): 281-289.DOI: 10.1016/j.cjche.2014.10.017

• ENERGY, RESOURCES AND ENVIRONMENTAL TECHNOLOGY • Previous Articles     Next Articles

Production of biodiesel from waste vegetable oil using impregnated diatomite as heterogeneous catalyst

Edward Modiba1, Christopher Enweremadu2, Hilary Rutto1   

  1. 1 Department of Chemical Engineering, Vanderbijlpark Campus, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1900, South Africa;
    2 Department of Mechanical and Industrial Engineering, University of South Africa, UNISA Science Campus, Private Bag X6, Florida 1710, South Africa
  • Received:2013-08-28 Revised:2014-02-10 Online:2015-01-24 Published:2015-01-28
  • Contact: Hilary Rutto

Production of biodiesel from waste vegetable oil using impregnated diatomite as heterogeneous catalyst

Edward Modiba1, Christopher Enweremadu2, Hilary Rutto1   

  1. 1 Department of Chemical Engineering, Vanderbijlpark Campus, Vaal University of Technology, Private Bag X021, Vanderbijlpark 1900, South Africa;
    2 Department of Mechanical and Industrial Engineering, University of South Africa, UNISA Science Campus, Private Bag X6, Florida 1710, South Africa
  • 通讯作者: Hilary Rutto

Abstract: In this study, biodiesel was produced from waste vegetable oil using a heterogeneous base catalyst synthesized by impregnating potassium hydroxide (KOH) onto diatomite. Response surface methodology based on a central composite design was used to optimize four transesterification variables: temperature (30-120 ℃), reaction time (2-6 h), methanol to oil mass ratio (10%-50%) and catalyst to oil mass ratio (2.1%-7.9%). A quadratic polynomial equationwas obtained to correlate biodiesel yield to the transesterification variables. The diatomite-KOH catalyst was characterized using X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR) and a scanning electron microscope (SEM) equipped with an energy dispersive X-ray detector (EDS). A maximum biodiesel yield of 90%(by mass) was obtained. The reaction conditions were as follows: methanol to oil mass ratio 30%, catalyst to oil mass ratio 5%, reaction time 4 h, and reaction temperature 75 ℃. The XRD, FTIR and SEM (EDS) results confirm that the addition of KOH modifies the structure of diatomite. During impregnation and calcination of the diatomite catalyst the K2O phase forms in the diatomite structural matrix and the active basicity of this compound facilitates the transesterification process. It is possible to recycle the diatomite-KOH catalyst up to three times. The crucial biodiesel properties fromwaste vegetable oil arewithin the American Standard Test Method specifications.

Key words: Central composite design, Transesterification, Impregnation, Diatomite

摘要: In this study, biodiesel was produced from waste vegetable oil using a heterogeneous base catalyst synthesized by impregnating potassium hydroxide (KOH) onto diatomite. Response surface methodology based on a central composite design was used to optimize four transesterification variables: temperature (30-120 ℃), reaction time (2-6 h), methanol to oil mass ratio (10%-50%) and catalyst to oil mass ratio (2.1%-7.9%). A quadratic polynomial equationwas obtained to correlate biodiesel yield to the transesterification variables. The diatomite-KOH catalyst was characterized using X-ray diffraction (XRD), Fourier transform infra-red spectroscopy (FTIR) and a scanning electron microscope (SEM) equipped with an energy dispersive X-ray detector (EDS). A maximum biodiesel yield of 90%(by mass) was obtained. The reaction conditions were as follows: methanol to oil mass ratio 30%, catalyst to oil mass ratio 5%, reaction time 4 h, and reaction temperature 75 ℃. The XRD, FTIR and SEM (EDS) results confirm that the addition of KOH modifies the structure of diatomite. During impregnation and calcination of the diatomite catalyst the K2O phase forms in the diatomite structural matrix and the active basicity of this compound facilitates the transesterification process. It is possible to recycle the diatomite-KOH catalyst up to three times. The crucial biodiesel properties fromwaste vegetable oil arewithin the American Standard Test Method specifications.

关键词: Central composite design, Transesterification, Impregnation, Diatomite