Comparing and Investigating the Effect of Functional Groups of Nano-Graphene Oxide (NGO) on Biodiesel Production from Jatropha Oil Using Density Function Theory

Abstract

In this study, the mechanism of biodiesel production from jatropha oil and methanol is investigated in the presence of nano-graphene oxide (NGO) with carboxy, hydroxy, and epoxy functional groups. This heterogeneous nano-catalyst can be included in the group of heterogeneous basic and acidic catalysts in biodiesel production. At first, optimized and simulated all geometric structures of jatropha oil (C57H104O6), methanol, biodiesel, and glycerin. Due to its double bond in Jatropha oil, it has two configurations of cis and trans. The obtained results show that the trans configuration is more stable when in proximity to the nano-catalyst. The structural and thermodynamic parameters were obtained and evaluated for the approach and interaction of jatropha oil with methanol on carboxy, hydroxy, and epoxy functional groups and converted to biodiesel by the DFT calculation method. Graphene oxide nano-catalysts have separation potential, reuse and removing neutralization and washing steps, reducing the amount of waste produced and most importantly reduction of cost. Among the functional groups on the edge of NGO, the hydroxy group has performed better than the carboxy functional group in terms of reaction speed and biodiesel production. Although the carboxy functional group is resistant to free fatty acids (FFAs) and water and can perform both transesterification and esterification reactions at the same time, their reaction time is much longer than the hydroxy functional group. At the same time, during electron exchange, the absorption energy of biodiesel production on the hydroxy functional group (k = 2.04 × 1011 h−1) is less than other functional groups of NGO.