Oil Adsorption of Exfoliated Graphite Prepared by Direct Reaction between $SO_3$ Gas and Graphite

Graphite intercalation compounds (GIC) were prepared by direct reaction of $SO_3$ gas with flake graphite. The intercalated $SO_3$ molecules were ejected by rapid heating to $950^{\circ}C$ under an oxidizing atmosphere for about 1 minute, resulting in surprisingly high expansion in the direction of c-axis. The characteristics of the micro-structure and pore size distribution were examined with a SEM and mercury intrusion porosimetry. The XRD analysis and spectroscopic analysis were used for the identification of the graphite and surface chemistry state. The pore size distribution of the exfoliated graphite (EG) was a range of $1{\sim}170{\mu}m$. The higher expanding temperature the higher expanded volume, so oil sorption capacities were 58.8 g of bunker-C oil and 34.7 g of diesel oil per 1 g of the the EG. The sorption equilibrium was achieved very rapidly within several minutes. As the treatment temperature increases, bulk density decreases.