Obtaining Biodiesel from Fat Extracted from Solid Waste Produced in the Fleshing Stage of Leather Manufacturing

Abstract

Tallow is produced in leather manufacturing, particularly in the fleshing stage. It contains large amounts of fat, which, in most industrial plants, pollutes water and soil due to poor disposal. In order to take advantage of this solid waste, chemical processes have been applied to transform the fats extracted from tallow into biodiesel. In this work, an extraction technique involving non-polar solvents pressurized at 15 psi. With gasoline, a 51,0% fat recovery was obtained. The quality of the extracted fat was determined by analyzing density, viscosity, melting point, moisture, acidity, and acidity, peroxides, saponification, and iodine indices. Biodiesel was obtained via transesterification reactions with methanol and sodium hydroxide. The content of methyl esters produced in the reaction was characterized by means of gas chromatography coupled with mass spectrometry, where the methyl esters of palmitic and oleic fatty acids were identified as major components.