REMEDIATION-POSTERAPPLICATION OF IRON OXIDE CATALYST TO DETOXIFY DIOXINSIN FLY ASH AND POSSIBILITY OF CALUX™
FOR SAVINGCALUX'^' ASSAYAANALYSIS COST AND TIME
Yasuhiko Fujii'. Toshiki Matsui', Junko Fujino",Masafumi Nakamura",
Hiroko Kitagawa", Hiroshi Murata", Tomoko Okila', Tomoyuki Imai''Toda Kogyo Corporation, 1-4. Meijishinkai,Otake,Hiroshima,739-0652, Japan"Hiyoshi Corporation, 908 Kitanoshocho, Omihachiman, Shiga, 523-8555, Japan

Introduction
In Japan 78%) of municipal solid wasle (51.2 million tons in 1997) was disposed by 1843
incinerators (1997)'. Dioxins (DXNs) such as polychlorinaled biphenyls (PCBs), polychlorinateddibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are generated in thecourse ofthe disposal by these incinerators. DXNs are chiefly discharged in exhaust gas or ashes.
In January 1997, the Ministry of Heallh and Welfare published "New Guideline" that proposedemission slandard for DXNs calling for concrete reductions in the amount of DXNs in exhausts".
"New Guideline" also indicated the necessity of restricting the lotal amount of the emissions ofDXNs. Therefore, in the near future emphasis would be placed on detoxifying fly ash containing
high concentration of DXNs and il would be expected that the disposal offly ash could be a moresignificant problem'. Japanese companies involved in constructing incinerators have slarted lo
develop new detoxifying lechnology for dechlorination of chlorinated organic compounds in ashand lo inlroduce Ihem inlo incinerator systems\ We have already reported on the efficiency of
the iron oxide catalyst for dechlorination of the polychlorinaled hydrocarbons^'^. However,optimizing the condilions by conventional analyzing methods can be costly and lime consuming,
thereby restricting the development of new disposal technology. In this sludy we report on theefficacy of iron oxide catalysis in the detoxification of DXNs during heating treatment of fly ash
originating from municipal incinerators. We also report on the effectiveness ofthe CALUX'^'^'
assay' in terms of cosls and limes compared vvilh HRGC/MS, especially for development of new
disposal and detoxification technology.
Material and Method
Materials
Fly ash samples from the dust catcher ofthe municipal solid incinerators were obtained froma cily in Tochigi prefecture and analyzed by public melhod and by the CALUX^"^^ assay
DXNs-TEQ ofthis ash was 6.9ng-TEQ/g by public melhod and 5.1 ng-CALUX- TEQ/g by theCALUX™ assay.
TIC-8048 ( a -FeO(OH), BET;86.3mVg) and TlC-0018 ( a -FesOj,BET; 111.6m'/g) used as catalyst were obtained from Toda Kogyo Corporation. The mixing
weight ratio of calalyst lo ash was 1:20 or 0:20. Ash and catalyst were mixed by placing bolh in apolyethylene bag and shaking by hand.
Experimental method
Figure I shows rotary kiln in batch operalion. The lotal kiln volume is 10 L and available
volume is 2 L. We treated fly ash in this rotary kiln in batch operation. The weight ofthe ash
was 400 g. The temperature of the ash during the operation was 303''~307° C and the retention
time ofthe trealmeni was 45 or 60 minutes. The operations were carried out wilh controlled flowof air (0 or 1 L/min). The samples treated in the various condilions indicated in Table 2 wereanalyzed by HRGC/MS and by the CALUX'^^' assay.

ORGANOHALOGEN COMPOUNDS
Vol. 54 (2001)

211

REMEDIATION-POSTER
HRGC/MS Public method
JIS K 0311 (1999) was applied to extracfion, purification and HRGC/MS analysis ofthe ashsamples.
CALUX™ Assay
The CALUX^*^ assay uses a patented recombinant mouse cell line that conlains the luciferase
reporter gene under conlrol of dioxin responsive elements'. When these cells are exposed lo
environmenlal ligands such as DXNs, luciferase protein is synthesized. The amount of light
produced by the luciferase proiein is directly related to DXNs-TEQ. The CALUX"^"' assay
melhod used has been described previously'.

Air 0-1 L/min

Activatedcarbon

exhaustoutsideThemiocouple
Figure 1. Diagram of rotary kiln used in experimenL
Retx.'^T^&tfiont C&D

Envtconmentol
Ugands: PCDHS,
PCBs. Dioxins.
a n d Furans•I A ' ^ ••:••••: .•iyri:• '••r'-t<airon3toao^< • - • • i ; —,rrfw?

^ ^ ^ ^ ^ f e ^ l # ^ > •• -"V .-j^P^^^^f:!? !l:".jjj$ V '1
I n d u d i o n of Hgw is directlyproporHonol to c o n c e n t r o l i o no l dioxin TEQ in tne sample.

DRE - Dioxin Responsive ElementOXt =Dloxin-lllie c o m p o u n d s : PCDHs.
PCBs. Dioxins a n d Furans
ARNTi = AnR Nuclear Tronsiocator protein
IATIR.Complexi =Aivl hydrocortxin Rocoptor C o m p l e x

Figure 2. Mechanism of the CALUX^'^' assay
Results and Discussions

Table 1 and Figure 3 show the distributions of DXNs congeners ofthe different treatmenls.
Table 2 .shows the experimenlal condilions and DXNs-TEQ data from the public melhod andCALUX assay. Under conditions wilh no supplemental supply of air (0 L/min) al aORGANOHALOGEN COMI'OUNDS
Vol. 54 (2001)

212

REMEDIATION-POSTER
temperature of 300° C (Run 1, Run 2 and Run 4), DXNs-TEQ were 6.7 ng-TEQ/g, 5.3 ng-TEQ/gand 3.2 ng-TEQ/g, respectively. These resulls indicated thai the addition of the iron oxide
catalyst enhanced detoxification of DXNs. The ralio of DXNs congeners was characlerized by
the increase of PCDFs in Run 1. Huang el. al, 1995' and Hagenmaier el. al., 1989'" poinled oulthat de novo synthesis of DXNs could contribute lo this increase. On the olher hand, with theaddition of TIC-0018 (Run 4), all DXNs congeners vvere reduced. These results suggested thatthe formation of DXNs was depressed by the presence ofthis catalyst.
Table I.

HRGC/MS analysis results ofthe heating treatment offly ash
Fly ashTtCDDsPeCDDsHxCDDsHpCDDs
OCDDs
TtCDFsPfCDFslliCDFs
HpDFi
OCDKs
PCDDs
PCDFs
PCDFs/PCDDs
Totnl DXNs

Run 2Run 1343638218.765402913L8138
149
1.08
287

Run 3

42
32
15
47
L6
130
54
13
2.6
0.16
95
200
2.1295

30
24
1349
L984
38
1130.2
74
136
1.85
210

•.

' •'::'^^^'Run 4Run 5

1713
8.8
2.9
1.2
40
21
8
1.5
0.14
43
71
1.65
114

28
20
13
48
1.7
68
24
9.6
2.5
0.2
68
104
1.55
172

R]

•

120
ushc

n

100

60
Q

40
•200i"I80. ..::«:.:„„

Ik Iw.

"::4.

Wk'"' t ^- ; — ~ r "-.
|' 1ltoi> WTm-i'llwi^i 1s;*.,-.

lhll. J •mrmn .rt

o<5^"^0."#P-N^f•^X^ \^0>.

0 ^2319113
1.1
110
68
24
3.5
0.25
57
206
3.6263• original a.':h• Run r •• Run 2
• Run 3
• Run 4
• Run 5
• Run 6140••••'%¥..:;:•.

Run 6

13128.3
2.5
0.64
20
125.7
10.096
36
39
1.06
75&

^^

•

.0^
x^^

.<5^'d^Figure 3. The Distributions of DXN congeners
Under conditions including a supply of air (1 L/min) al a temperature of 300° C (Run 3, Run5 and Run 6), DXNs-TEQ were 4.5 ng-TEQ/g, 2.5 ng-TEQ/g and 6.5 ng-TEQ/g, respecfively.
These results also indicated that the addilion ofthe iron oxide catalyst enhanced detoxification ofDXNs. Especially in Run 5, all of the DXN congeners were lower than the original fly ash.

ORGANOHALOGEN COMPOUNDSVoL 54 (2001)

213

REMEDIATION-POSTER
This result indicates the superiority ofthe addition ofthe iron oxide catalyst lo the treatment for
detoxifying DXNs. The DXNs-TEQ of Run I was almosi equal lo that of Run 6, so it may beconcluded that DXNs-TEQ was scarcely affected by supply of air (in the range of 0 to 1 L/min) inthe absence of iron oxide catalyst. In contrast under the condilions ofthe addilion of iron oxide
catalyst TlC-8048 and TlC-0018, from the results of Run 2, Run 3, Run 4 and Run 5, as a resull of
supply of air, DXNs vvere decreased aboul 20%. This indicated that supply of air was necessary forbeller treatment in the case ofthe addilion of iron oxide.
The resulls from the CALUX^'^' assay were showed in Table 2. From these data, il wasconfirmed that DXNs-CALUX • TEQ/g were also diminished by the addition of TlC-8048 orTlC-0018. Moreover the supply of air enhanced the detoxification of DXNs. These dala also
indicated that the results from the CALUX^'^ assay were sirongly correlated with those fromHRGC/MS, thereby from the standpoint of ils rapidity and costs the CALUX^'"'^ assay wasappropriate to analyze DXN-TEQ in the case of development of new technology.
Conclusions
The effecl of detoxifying DXNs was confirmed in the course of heating treatmeni of fly ash
by the addilion of iron oxide calalyst, TIC-8048 and especially TIC-0018. But the subject todefine the mechanism of this detoxification of DXNs in ash remains. So il is necessary lofurther examine the relationship belween exhausl gases from the treatment and the concentrationof DXNs remaining.
We previously reported the sirong cortelation of CALUX^"^' resulls with HRGC/MS data^
In this study the HRGC/MS data and CALUX^"^ resulls were also strongly correlated. Based onthese results the CALUX^"^' assay vvill be useful for optimizing the methods and condifions for thedetoxification of DXNs. The advantages of the CALUX^' assay over HRGC/MS: rapidity,convenience and lower cost; should aid in the developmenl of these detoxification methods.
Table 2. Treatment conditions and results of the heating treatment of the fly ash
Run

wciRht orwcighl 0 r i h cashl y p e of ironoxideiron oxide

M(«)-D.XNs - T T O

supply if air

temperatureof ashes

retentiontime

coniing time

(L'm • i )CO(min)(min

public me liod

C A I . U X ' " assay(nh- n£o •tf)

(in-CALIiX- rEQ/s)

I-100-0303

1520

6.7

3.02

•100

IIC-SO^IS200303

AS

20

5.3

2.0

3

•100

TIC-SO.18

201307

AS

20

•1.5

1.6

•1•100

TIC-0018

200303

60

20

3.2

2J5400

TIC-0018

201303

60

20

2.5OX

6

•100-1303

60

2065

M-References
1. Japanese wasle disposal (1997), Published by Ministry of Heallh and Welfare, Japan.
2. Guidelines for the inhibition of dioxins concerning with disposal of municipal solid waste(1997), Published by Ministry of Heallh and Welfare, Japan.
3. Shiomitsu, T., Hirayama, A. and Ishida, T. (2000). Japan Society of Waste Management
Expert Joumal containing research paper compendium 11, 818-820.
4. Kanda, N., Sugiura, K. and Itagaki, S. (1998). Japan Sociely of Wasle Management Expert
Joumal containing research paper compendium 9, 742-744.
5. Tomoyuki, I., Toshiki, M., Yasuhiko, F. and Tomoko, O. (2000). Journal of the Chemical
Society of Japan, No. 8.
6. Tomoyuki, 1. and Tomoko, O. (1998). 82lh Catalysis Society of Japan Meeting. A61.
7. Denison, M., Brouwer, A. and Clark, G. (1998). U.S.paleni # 5,854,010
8. Brown, D., Kishimoto, Y, Ikeno, O., Chu, M., Nomura, J., Murakami, T., and Murata, H.
(2000) Organohalogen Compounds 45: 200-203.
9. Huang, H., Buekens, A., el al, (1995). Chemosphere 31,4099.
10. Hagenmaier, H., Kraft, M., Haag, R., (1989). International Conference on MSW.
ORGANOHALOGEN COMPOUNDSVoL 54 (2001)
214