Valorization of energy crop shells as potential green adsorbents for free fatty acid removal from oils for biodiesel production

Due to the success of the use of energy crop oils in the production of biodiesel, the heavy cultivation of these plants in many countries is being promoted. However, it may lead to the problem with its associated waste shells, which contain low nutrient; consequently, they are not suitable for use as an agricultural fertilizer, and they are abundant in hemicellulose, cellulose, and lignin resulting in difficult to digest or degrade. Thus, a possible solution for this waste is to convert it into carbon-based adsorbents. Specifically, activated carbon is a product with a high added value, widely used material due to its adsorbent properties. These adsorbents could be used for reducing the free fatty acids content presents in oils intended for the biodiesel production. The presence of free fatty acids in the oils is undesirable for biodiesel production due to a performance reduction in the transesterification reaction. The aim of this work is to use biomass waste such as Jatropha curcas and Pongamia pinnata shells for the preparation of carbon-based materials (activated carbons, Ca(OH)2 supported on activated carbons and charcoals) and to study the possibility of using them as adsorbents for reducing the free fatty acids content of Jatropha curcas and Pongamia pinnata oils.