32
H.V 50mm Gas in Gas out 260mm 15mm H.V 37mm 0.5mm Vis Sample setting 33 UV
Light emission spectra of oxygen and air plasmas. Intensity (arb.units) 70000 60000 50000 40000 30000 20000 10000 Air, 60 Pa Intensity (arb.units) 700 600 500 400 300 200 100 OII OII + O 2 + O 2 1 O 2 OI OI OI 20Pa 40Pa 60Pa 80Pa 0 200 300 400 500 600 700 800 Wavelength (nm) 0 400 500 600 700 800 900 1000 Wavelength (nm) w/oplasmairradiation 30minplasmairradiation Aspergillus Oryzae 34 34
Sporeofyeast/mold Control Ozone60ppm UV254nm UV+ozone 35
+ w/otreatment plasmairradiation for5min plasmairradiation for10min plasmairradiation for20min Sporeofyeast/mold Inactivation rate (%) 100 80 60 40 20 0 5 10 15 20 Plasma irradiation period (min) 0.20 without irradiation after irradiation C-H stretching Absorbance (arb.units) 0.15 0.10 0.05 C-C stretching C=O stretching Amide I N-H stretching w/o plasma 0.00 1000 2000 3000 4000 Wavenumber (cm -1 ) plasma irradiated ATR FTIR spectra of Lemon peel surface Atmospheric torch plasma+uv light irradiation 36
䊒䊤䉵䊙ᾖ 䈮䉋䉎䈮䉖䈛䉖 ሶ䈱 ଔ Experimental Condition Irradiation period:15,30,45,60,120,180 min Pressure:60 Pa RF power:60 W Plasma gas: Pure oxygen Cultivation period:24 hours Ḱኙᄤ 䈮䉋䉎 㙃(Control) 䈮䉖䈛䉖 ሶ 䈮䉖䈛䉖 ሶ䈻䈱䊒䊤䉵䊙ᾖ 120min 30min 45min No.of colonies [*104 CFU/g] 15min 180min 60min 300 200 100 0 0 50 100 150 200 Plasma irradiation period [min] 䊒䊤䉵䊙ᾖ 㑆䈫䉮䊨䊆䊷ᢙ䈱㑐ଥ 37
Experimental condition Irradiation period: 60,120,180 min Pressure: 60 Pa RF power: 60 W Plasma gas: Pure oxygen Cultivation period:24 hours Control 60min 120min 180min 38
5-7 kv O 8-9 khz 60W 1/min 2ml Radical production in gas phase H 2 O 2 generation in liquid NO 2 concentration O 3 concentration Air greenish 5.0mg/L 0mg/L Oxygen greenish < 5.0mg/L 2.0mg/L Ar no change 25.0mg/L 0mg/L Power input 60 W, Gas flow rate : 2.0 L/min Treatment period : 20 min Ar and nitrogen meta-stable particle decompose H 2 O and produce H 2 O 2. The oxygen plasma does not generate hydroxyl peroxide in water. The Ar meta-stable generates nitrous acid in water effectively. 39
Nornalized population of bachilli Treatment period (min) = 70 plasma treatment Nornalized population of bachilli 50 40 70 80 Treatment period (min) 10 0 Heat treatment 10 0 Plasma treatment Survival rate (log CFU/ml) 10-1 10-2 10-3 10-4 10-5 55 60 Survival rate (log CFU/ml) 10-1 10-2 10-3 10-4 10-5 1.010 7 /ml 1.010 6 /ml 1.010 5 /ml 10-6 0 5 10 15 20 Irradiation period (min) 10-6 0 5 10 15 20 Irradiation period (min) Vibrio vulnificus Vibrio vulnificus 40
Positive pulse discharge 3 40 Discharge electrode Current (A) 2 1 0 30 20 10 0 Applied voltage (kv) Oscilloscope Discharge vessel -10 0.0 0.2 0.4 0.6 0.8 1.0 Time (s) Power Source Sample water CCD Camera 41
O 3 outlet Active carbon Orifice ejector O 3 inlet O 3 gas monitor Ozonizer 1000mm Flow meter O 2 UV lamp (253.7nm) Water Water pump 300mm Dissolved O 3 monitor Tank reactor Initial number about 10 6 CFUs/ml After 5 min. discharge about 10 2 CFUs/ml After 30 min. discharge about 10 CFUs/ml Medium sheet for microbial detection : Sanita-kun 42
Pulsed streamer discharge condition: 25kV, 10Hz solution: 0.84mS/m AC corona discharge condition: 16kV p-p, 10kHz solution: 0.84mS/m 10 6 E. coli 10 6 E. coli 10 5 B. subtilis 10 5 B. subtilis 10 4 10 4 CFU/ml 10 3 10 2 CFU/ml 10 3 10 2 10 1 10 1 10 0 10 0 10-1 0 5 10 15 20 25 30 Treatment time (min.) 10-1 0 5 10 15 20 25 30 Treatment time (min.) 43