Synthesis of heterogeneous catalysts by the hydrolytic Sol-Gel method for the biodiesel production

The biodiesel is important as a renewable fuel, but some parameters of the industrial production, such as the use of homogeneous catalysts and the large quantities of residues (wastewater and glycerin) are a problem. In this work, four heterogeneous catalysts were synthesized by the hydrolytic Sol-Gel method for the biodiesel production and to possible reduce the production costs because the catalyst can be reused. The catalyst can also reduce the wastewater and glycerin contaminations. The catalysts were characterized by X-ray diffraction, basicity determination, and infrared spectroscopy. According to the National Agency of Petroleum, Natural Gas and Biofuels, the biodiesel samples were characterized by specific gravity, copper corrosivity, kinematic viscosity, acidity, Karl Fischer coulometry, and gas chromatography. The wastewaters were characterized by ultraviolet and visible spectroscopy, pH, dissolved oxygen, ashes, and solids (total, volatile, and non-volatile). The wastewater from heterogeneous catalysis was less harmful to the environment and can be easily treated, with reduction of 78.58% of organic residues to be converted by the wastewater treatment. In conclusion, the new catalyst produced biodiesel successfully and showed high catalytic activity (97.58% of ester content and 92.94% of yield), and produced wastewater and glycerin with lower amount of residues (eco-friendly).