Biodiesel preparation from Camelina sativa oil by homogeneous and heterogeneous transesterification

Abstract

Biodiesel is one of the possible alternatives to diesel fuel to address the issue of fossil fuels and their impact on the environment. Substituting homogeneous transesterification with heterogeneous offers advantages such as improved catalyst and product separation, catalyst regeneration, and avoidance of saponification during the reaction. To compare homogeneous and heterogeneous transesterification, the commonly used homogenous catalyst NaOH was tested. As a heterogeneous catalyst, a mixed oxide prepared from hydrotalcite with added nickel in its structure was used. By employing suitable conditions, it is possible to achieve biodiesel through heterogeneous transesterification with a comparable FAME (Fatty acid methyl ester) content to homogeneous transesterification, meeting the standardized value of over 96.7 wt.%. Implementing a two-step heterogeneous transesterification process decreases the reaction time needed to reach the desired FAME quantity. Furthermore, following heterogeneous transesterification, glycerol as a valuable secondary product showed visibly higher purity.