A rapid and efficient method to prepare exfoliated graphite by microwave irradiation

Exfoliated graphite materials had been rapidly and efficiently prepared by microwave irradiation in a short time (about 4 min including 3 min mixing and 1 min microwave irradiation). The promotion of the intercalation by microwave irradiation was proven by X-ray diffraction. With increasing content of oxidant and intercalation agent, the expanded volume of exfoliated graphite increased at first and then decreased. When the weight ratio of natural graphite and nitric acid to potassium permanganate was set at 1:2:1, the expanded volume of exfoliated graphite reached the maximum value (312 mL/g) and sorption capacity of this exfoliated graphite was 56 g of engine oil and 32 g of kerosene per 1 g of exfoliated graphite. (C) 2008 Elsevier Ltd. All rights reserved.