Impact of N, O Heteroatoms in Asphaltene on Adsorption of Vanadyl/Nickel Etioporphyrin

[Image: see text] The interaction between functionalized graphene and metal porphyrins was studied for a better understanding of the influence of the N and O heteroatoms in asphaltene on demetallization efficiency during the solvent deasphalting process. The theoretical simulation indicated a strong inhibitory effect of the aminated/carboxylated side group for chemical adsorption of metal porphyrins. The differences of adsorption behavior for graphene, aminated graphene, and Canadian oil sands bitumen vacuum tower bottom asphaltene (VTB-asp) were also analyzed. It was found that the introduction of aminated side groups to the graphene not only compromised the electron delocalization capacity of the polyaromatic nuclei hydrocarbon skeleton of graphene but also caused a steric hindrance effect on the internal diffusion of metal porphyrins, leading to decreased adsorption active sites and internal diffusion rate, respectively. It was also found that metal porphyrins can be barely adsorbed on carboxylated graphene at 25 °C.