Usage of silica xerogel from African sugarcane leaves as a catalyst in biodiesel production through transesterification

Abstract

Biodiesel was produced through transesterification from canola oil and methanol in the presence of silica xerogel derived from sugar cane leaves as a solid catalyst. The transesterification reaction was carried out at 65 °C in a batch-type reactor where a three-neck round-bottom flask was used as a reaction vessel with a reflux setup. Reaction time, methanol to oil ratio, and weight percentage of the catalyst were varied to optimize the biodiesel yield. The xerogel catalyst was characterized by inductively coupled plasma-optical emission spectroscopy (ICP-OES), nitrogen physisorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The produced biodiesel was characterized using gas chromatography-mass spectroscopy (GC-MS), Fourier transform infrared spectroscopy (FTIR), and a viscometer. The synthesized catalyst was found to operate as a true heterogeneous catalyst, since it preserved its solid nature and did not leach into the reaction medium. A biodiesel yield of 96.9% was achieved under optimal reaction conditions of 60 min reaction time, 6:1 methanol to oil ratio, and 3 wt % catalyst loading. The produced biodiesel was found to have a mixture of both saturated and unsaturated fatty acid methyl esters and had physical properties that met the ASTM and EN standards. The investigated catalyst was found to have a potential of being recycled up to 3 times, which positively affects the biodiesel production costs.