Synthesis of calcium materials in biochar matrix as a highly stable catalyst for biodiesel production

In this study, the biochar which was obtained from peat was modified and served as the support for the preparation of cost-effective solid base catalysts for the transesterification reaction. The composition, structure and texture of prepared catalysts were examined by scanning electron microscope (SEM), energy dispersive spectrometer (EDS), N2 adsorption/desorption, Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA) and the Hammett indicator method. It was found that the surface area and pore volume of the peat biochar were increased significantly (from 80.25 m2/g and 105.36 mm3/g to 230.86 m2/g and 296.23 mm3/g, respectively) by chemical activation treatment with KOH. The best performance is observed for the resulting 30Ca/APB-700 catalyst (30% CaO loading and 700 °C calcination temperature), and over biodiesel yield of 93.4% was achieved at catalyst amount of 5 wt.%, methanol/oil molar ratio of 8:1 and reaction time of 150 min. Besides, after reused for 10 cycles, the catalytic efficiency had a slight deactivation in biodiesel production (above 81.6% of yield obtained). The high stability of catalyst was mainly attributed to the formation of CaOSi bond on the catalyst surface.