• 한국환경과학회지
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• 제27권8호
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• pp.621-629
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• 2018

Many chemically active species such as ${\cdot}H$, ${\cdot}OH$, $O_3$, $H_2O_2$, hydrated $e^-$, as well as ultraviolet rays, are produced by Dielectric Barrier Discharge (DBD) plasma in water and are widely use to remove non-biodegradable materials and deactivate microorganisms. As the plasma gas containing chemically active species that is generated from the plasma reaction has a short lifetime and low solubility in water, increasing the dissolution rate of this gas is an important challenge. To this end, the plasma gas and water within reactor were mixed using the air-automizing nozzle, and then, water-gas mixture was injected into water. The dissolving effect of plasma gas was indirectly confirmed by measuring the RNO (N-Dimethyl-4-nitrosoaniline, indicator of the formation of OH radical) solution. The plasma system consisted of an oxygen generator, a high-voltage power supply, a plasma generator and a liquid-gas mixing reactor. Experiments were conducted to examine the effects of location of air-automizing nozzle, flow rate of plasma gas, water circulation rate, and high-voltage on RNO degradation. The experimental results showed that the RNO removal efficiency of the air-automizing nozzle is 29.8% higher than the conventional diffuser. The nozzle position from water surface was not considered to be a major factor in the design and operation of the plasma reactor. The plasma gas flow rate and water circulation rate with the highest RNO removal rate were 3.5 L/min and 1.5 L/min, respectively. The ratio of the plasma gas flow rate to the water circulation rate for obtaining an RNO removal rate of over 95% was 1.67 ~ 4.00.

• 한국산업보건학회지
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• 제29권3호
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• pp.414-419
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• 2019

Objectives: The objective of this study was to evaluate the inhibitory effect of non-thermal dielectric barrier discharge (DBD) plasma by air volume against Mycobacterium tuberculosis (MTB). Methods: Plasma generators (TB-300, Shinyoung Airtec, Seongnam-si, Korea) were operated in a 2A type biosafety cabinet. The plasma generator was set to a wind flow rate of 14 ($80m^3/h$), 18 ($110m^3/h$), and 22 ($150m^3/h$), and exposure times were set to 0 hours, 3 hours, 6 hours, 9 hours, and 24 hours. Results: The inhibitory effects of plasma at air volume 14 with prolonged exposure time of three hours was 20%, 64% at six hours, 82.3% at nine hours, and 100% after 24 hours exposure. With air volume of 18, the inhibitory effects upon plasma exposure were 36% for three hours, and 100% from 24 hours. Greater air volume resulted in greater inhibition of tuberculosis bacterial growth. In particular, the maximum inhibitory effect (100%) was shown in air volume of 22 ($150m^3/h$) after three hours of plasma exposure. Conclusions: The results showed the correlating inhibitory effects of plasma on the growth of MTB in combination with increasing plasma exposure time and air volume.