Minju Lee

Chung-Ang University, Sŏul, Seoul, South Korea

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Publications (2)7.03 Total impact

  • Minju Lee, Jeill Oh
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    ABSTRACT: The synergistic effect of H(2)O(2) production and sonochemiluminescence (SCL) was studied under both orthogonal and opposite dual irradiation at the frequencies of 28, 584 and 970 kHz and at various acoustic powers. The largest reduction in H(2)O(2) production was observed under opposite dual irradiation at a 28/28 kHz frequency without considering the acoustic power levels. The largest enhancement was observed under dual irradiation at a frequency of 28/970 kHz. This enhancement might be due to the increased number of bubbles that underwent violent collapse by low frequency ultrasound (28 kHz). These results were also confirmed by observing the SCL. Under dual irradiation at relatively high frequencies (i.e., 584 and 970 kHz), the synergistic effect was high at low acoustic power levels. However, the effect tended to decrease (to the equivalent of the calculation from the result of each single irradiation) with increasing acoustic power. Unlike dual irradiation coupled with a frequency of 28 kHz, the inhibition effect was not observed under dual irradiation at relatively high frequencies. With respect to H(2)O(2) production, the production rate constants of H(2)O(2) followed the order of 584/584>584/970>28/970≈28/584>28/28 kHz, which resulted from the fact that the production efficiency of H(2)O(2) at an irradiation frequency of 584 kHz was considerably higher than that at other frequencies.
    Ultrasonics Sonochemistry 05/2011; 18(3):781-8. · 3.52 Impact Factor
  • Minju Lee, Jeill Oh
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    ABSTRACT: Herein, the ultrasonic degradation of trichloroethylene (TCE) and carbon tetrachloride (CT) are reported. The degradation rate for TCE increased by 27% with a decrease in the initial concentration of TCE from 10 to 1 mg L(-1), while the degradation rate of CT was not influenced significantly (<3%) at varying initial concentrations. The addition of t-BuOH, a hydroxyl radical scavenger, decreased the degradation rate of TCE to 22-33%. However, this addition did not affect the degradation rate of CT. Sonolysis of aqueous mixtures of TCE and CT indicated that the degradation rate of TCE was enhanced significantly in the presence of CT, while the degradation rate of CT was slightly inhibited in the presence of TCE. The enhancement of TCE degradation is attributed to both the increase of hydroxyl radical concentration by scavenging of CT for hydrogen atoms and the generation of chlorine-containing radicals such as CCl(3)(*), CCl(2)(*), Cl(*), and HClO from pyrolysis of CT during sonolysis of CT.
    Ultrasonics Sonochemistry 07/2009; 17(1):207-12. · 3.52 Impact Factor

Publication Stats

4 Citations
7.03 Total Impact Points

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Institutions

  • 2009–2011
    • Chung-Ang University
      Sŏul, Seoul, South Korea