The preparation and exfoliation of graphite oxide at low temperatures (near room temperature) to produce exfoliated graphite (EG) instead of rapid heating to a high temperature (conventional process) are reviewed. The exfoliation by microwave irradiation, electrochemical exfoliation and surfactant-assisted exfoliation of graphite are also included because these techniques can be applied under ambient atmosphere, although last two techniques were mainly applied for thinning the graphite flakes to obtain “graphene” flakes. The applications of the resultant exfoliated graphite (EG) for oil/water separation, adsorptive removal of the environment pollutants and microwave shielding are shortly reviewed.

Herein, the edges in carbon materials were quantitatively evaluated by summing the amount of hydrogen and the amount of functional groups without hydrogen in the material. The amount of hydrogen in the carbon material was quantitated via temperature-programmed oxidation (TPO) under an oxygen atmosphere, whereas the amount of functional groups was determined via temperature-programmed desorption (TPD) of the sample under an inert atmosphere. Consequently, the amount of edges in exfoliated carbon fibers prepared from polyacrylonitrile (PAN) (referred to as PAN-1000) was 9.4 mmol g−1. In addition, Ketjen Black (KB) and activated carbon (AC) had edge content of 1.3 and 3.6 mmol g−1, respectively. Because the total amount of functional groups of PAN-1000, KB and AC were estimated to be 8.18, 0.082 and 1.02 mmol g−1 via TPD, the total amount of edges and oxygen-containing functional groups of each sample could be quantified. The difference between amount of edges and the amount of functional groups is speculated to correspond to the amount of edges terminated with hydrogen. This study revealed that detailed information about the edges such as their proportion terminated with oxygen-containing functional groups, the species and amount of oxygen-containing functional groups via a combination of TPO and TPD.

Exfoliated graphite was found to sorb selectively a large amount of heavy oil, about 80 g of heavy oil floating on water per 1 g of exfoliated graphite, which is highly possible to be applied to recovering spilled heavy oil. Sorption capacity, selectivity and kinetics of exfoliated graphite were reviewed. The possibility of recovery of heavy oil from exfoliated graphite and recycling of both recovered heavy oil and exfoliated graphite was also discussed. Its sorption performance was compared with other materials which were reported to show sorption of heavy oil.