Study of ozone oxidation of dimethyl sulfide andsurface analysis of iodine catalysts
Yoshinori Mizuno1, 2, Ahmad Guji Yahaya2, Jaroslav Kristof2,Eizo Murakami1 and Kazuo Shimizu2
1 Asahikogyosha Co. Ltd., Japan. 2 Shizuoka University, Japan.

2. Materials

1. XEL: Ozone generator
VUVElectricwires

Mesh electrode(energized)
Xe plasma

Quartzglass

4. Surface analysis of catalyst

Samplingports
Ozone and(CH3)2S

Clean
Air
PostFilter

Catalyst

2. Experimental condition
Inlet (CH3)2S: 3 ppm
Inlet Ozone: 0 - 12 ppm
Flow velocity: 0.15 m/s
Filling length: 72 mm
Residence time: 0.48 s
Environment: 25 ℃ 45 %4. Results and discussions
1. Discharge power of XEL

The Discharge power waveformof the XELPower consumption of one-shot pulse
was calculated by integration of thedischarge power and its value was
187 μJ. Power consumption wascontrolled by pulse frequency.

Iodide (I-) can be oxidized to iodic
acid (IO3-) by ozone. And, iodic acidcould oxidize the dimethyl sulfide dueto the high oxidation potential. Thus,
iodine could be useful as an ozone
oxidation catalyst.

Intensity [a. u. ]In this research, 3-types granular
activated carbons were tested as
catalyst. Impregnation materials aredescribed as below.
・No impregnation (AC)・Iodine (AC-I)
・Iodine and H2SO4 (AC-I/S)

630
625
620
Binding energy [eV]615

pH measurement
AC
9.7

AC-I
9.8

AC-I/S
2.4

pH decrease could be due to theacid dissociation of H2SO4.
According to the XPS analysis,
Iodine (3d) peaks were detected from
AC-I and AC-I/S. The binding energyof I3d5/2 was about 617 ~ 618 eV for
both AC-I and AC-I/S. Thus, iodide
was the major state in AC-I and ACI/S.
Theseresults
showdifference
between AC-I and AC-I/S in surface
acidity, however, iodine states weresimilar.
200

AC

150

AC-I
AC-I/S

100
50
0
0.0

1.0
2.0
3.0O3/DMS ratio [-]

1.0
0.8
0.6
0.4
0.2

Breakthrough time versus
ozone concentration

5. Conclusion

0.0
120

140
160
180
Wavelength [nm]4.0

In AC and AC-I, breakthrough time
did not change by ozone addition.
However, in AC-I/S, breakthroughtime
wasincreasedbyozone
addition. Thus, surface acidity isimportant in iodine catalyst andacidic property is suitable.

2. Emission spectra of XEL

The photo image ofactivated carbon

AC-I/S

5. Gas treatment experiment

The schematic image of the XEL

2. Activated carbon (catalysts)

AC-I

Iodine XPS analysis

When outlet of dimethyl sulfide
concentration approached 5 % ofinlet, the catalyst is regarded asbreakthrough. Breakthrough time ofdimethyl sulfide was measured

Mesh electrode(Grounded)

Pulsed negative high-voltage wasapplied to the XEL. Vacuum-UltraViolet (VUV) was emitted from Xe
plasma.
Oxygenmolecules
wasdecomposed by VUV ozone wasgenerated.

AC635

The schematic image ofthe experimental setup

Breakthrough time [h]In this research, ozone catalyticoxidation using xenon excimer lamp
(XEL) and iodine (I- and IO3-) catalyst
were studied to compose the air
purification equipment inexpensively.
XEL was used for ozone generation.
Catalytic ability was investigated bygas
treatment
experiment,
andsurface analysis was conducted by pH
measurement and XPS analysis.

3. Methods
1. Experimental setupIntensity [a. u.]

1. Introduction
Wastewater treatment facilities areattracting much attentions owing to
the sustainable development goals(SDGs). These facilities emit dimethyl
sulfide ((CH3)2S, DMS) due to the
decay of organic compounds, and air
purification systems are needed toprevent offensive odor pollution.

200

The emission spectra of XEL
Light emission of peak wavelength of
172 nm, full width at half height of 16
nm was observed. This characteristic
light is emitted by xenon excimer.

3. Ozone generation by XEL

Ozone generation efficiency of XEL
was 19 kWh/kg. And, NOx/Ozone wasless than 0.3 %. XEL could generate
ozone without NOx generation.

 XEL emit 172 nm VUV by Appling
negative pulsed high voltage.
 XEL could generate ozone without
NOx generation.
 Activated carbon impregnated with
only iodine was not applicable asozone catalyst. However, activatedcarbon impregnation with iodineand H2SO4 could be utilized asozone catalysts.
 surface acidity is important in
iodine catalyst, and acidic property
was suitable for applicable inozone catalytic oxidation.