Biodiesel production via transesterification of low grade cooking oil over heterostructure nano particles of ni/mg/al2o3 catalyst

Abstract

Biodiesel which were synthesis from transesterification reaction in the present of heterogeneous base catalyst has been intensively studied over the last decades. This catalyst has an excellent result in producing high percentage conversions of biodiesel without further purification and cleaning process which contribute to the water pollution and high water content in biodiesel product. So, this study was conducted to synthesize and characterize series of heterostructure Ni/Mg/Al2O3 catalysts with different parameters to test their effectiveness towards the catalytic transesterification reaction. Series of Ni/Mg/Al2O3 catalysts were synthesized by wetness impregnation method supported on γ-alumina beads. Three parameters were studied include calcination temperatures, dopant ratios to base and numbers of alumina coating. The activity of the catalyst in transesterification reaction was evaluated at 65ºC of reaction temperature, 3 hours of reaction time, 6% w/w of catalyst loading and 1:24 molar ratio of oil to methanol. The potential catalyst was characterized by N2 Adsorption Analysis, TEM (BIO-TEM) and CO2-TPD. Meanwhile, the performance of the catalyst was evaluated using GC-FID. From the data obtained, Ni/Mg(20:80)/Al2O3 catalyst calcined at 800°C and three times alumina coating have the highest weak and moderate basic sites that contribute to the highest percentage conversion of low grade palm oil to biodiesel compared to others. Besides that, BIO-TEM result showed that the particle was non-homogeneous shape with a mixture of square sheet and one dimensional heterostructure nano-rod particles was observed. The data obtained from CO2-TPD and N2 Adsorption Analysis (NAA) prove that high basicity of the Ni/Mg(20:80)/Al2O3 catalyst (2.80 mmol/g) and high surface area (125 m2/g) had led to 78.53% of biodiesel conversion.