Abstract
Carbon nanomaterials were synthesized in water, sulfuric acid and ethylene glycol by ultrasonic irradiation under ambient conditions. In all cases performed, the solutions turned brown or black and insoluble soot was obtained after sonication time of several hours. Observation with a transmission electron microscope confirmed that the particles were graphite and the size of which was on the order of 100 nm in diameter. In the corresponding sonochemical reaction field, the temperature of cavitation bubbles was estimated by spectral analysis of exited-state C_2 emission observed during multibubble sonoluminescence. In the sonochemical field at 32 kHz in sulfuric acid, the temperature of cavitation was estimated at 7000 K-8000 K. In spite of the higher temperature than water, the production was not significantly different from that in water.
