Ethylene Decomposition with EAW
795
decomposition rate in EAW of the same pH values.
References
It is therefore considered that EAW at pH 2.5
delayed the senescence of carnations by preventing
an accumulation of ethylene.
1
2
3
4
5
)
)
)
)
)
Doi, T., Kato, R., and Tomita, M., Use of sterilized
electrolyzed water in food sanitation systems. Foods
and Food Ingredients J. (in Japanese), 177, 27–34
Ethylene was decomposed in the presence of avail-
able chlorine in the basic solutions (Fig. 2), being
decomposed to ethylene chlorohydrine in EAW, and
the rate of ethylene chlorohydrine production was
markedly lower in EAW at pH 5 or more (Fig. 5(b)).
These results suggest that the main available chlorine
involved in the decomposition of ethylene was prob-
(
1998).
Nakao, M., Yokota, K., Oguma, K., and Takai, K.,
Bacteriocidal eŠect of electrolyzed anode water on
Helicobacter pylori. Kansensyogaku Zasshi (in
Japanese), 74, 120–127 (2000).
Takahashi, K., Arita, M., Takai, K., and Kanemasa,
Y., Study on the bacteriocidal eŠect of a slightly
alkaline electrolyzed solution. Kankyo Kansen (in
Japanese), 14, 136–140 (1999).
Miyamoto, M., Inoue, K., and Gu, Y., EŠectiveness
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Tsuji, S., Kawano, S., and Oshita, M., Endoscope
disinfection using acidic electrolyzed water.
Endoscopy, 31, 528–535 (1999).
ably Cl
2
, and that ethylene was broken down through
the following reaction:
CH CH
2
=
2
+
H
2
O
+
-
Cl
2
ª
CH
2
Cl–CH OH
2
+
+
H
+
Cl
In EAW at or near pH 2.5, since ethylene reacts
with Cl , the equilibrium in reaction 1 is inclined
toward the left. Therefore, Cl was probably steadily
(2)
2
2
supplied from HClO, and ethylene chlorohydrine
equimolar to the available chlorine was ˆnally pro-
duced. A gradual production of ethylene chlorohy-
drine was observed after ethylene ventilation at
pH 5.0 (Fig. 3). This is considered to have been
caused by the reaction of HClO with residual ethy-
lene dissolved in EAW through following reaction 3,
the second-order rate constant of this reaction prob-
ably being smaller than that of reaction 2:
6) Fujiwara, K., Iimoto, M., and Fujiwara, M.,
Fundamental studies on crop disease control by
spraying electrolyzed strongly acidic water. Environ.
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7
)
Ohta, K., and Harada, K., EŠect of electrolyzed
anode water on the vase life of cut rose ‰owers. J.
Japan Soc. Hort. Sci. (in Japanese), 69, 520–522
(
2000).
8
9
)
)
Yang, S. F., and HoŠman, N. E., Ethylene biosyn-
thesis and its regulation in higher plants. Annu. Rev.
Plant Physiol., 35, 155–189 (1984).
Nichols, R., Ethylene production during senescence.
J. Hort. Sci., 41, 279–290 (1966).
CH
2
=
CH
2
+
HClO
ª
CH
2
Cl–CH
2
OH
(3)
As shown in Fig. 5(a), the amount of ethylene
chlorohydrine produced 1 min after ethylene ventila-
tion was no diŠerent between EAW at pH 2.5 and
1
0) Serrano, M., Romojaro, F., Casas, J. L., and
Acosta, M., Ethylene and polyamine metabolism in
climacteric and nonclimacteric carnation ‰owers.
Hort. Science, 26, 894–896 (1991).
4
.0, but the decomposition rate of ethylene to ethy-
lene chlorohydrine was faster at pH 2.5 than that at
pH 4.0 when EAW had been diluted twice to reduce
the available chlorine and the ethylene concentration
had also been reduced to one-ˆfth. It is considered
1
1
1) Brandt, A. S., and Woodson, W. R., Variation in
‰
ower senescence and ethylene biosynthesis among
carnations. Hort. Science, 27, 1100–1102 (1992).
2) American Public Health Association, American
Water Works Association and Water Environment
Federation, ``Standard Methods for the Examination
of a Wter and Wastewater'' 18th ed., American Pub-
lic Health Association 1992.
that the reaction between ethylene and Cl was faster
2
and completed within 1 min when there was no dilu-
tion of EAW and ethylene.
Recent reports about the sterilizing eŠect of elec-
trolyzed water have demonstrated that the sterilizing
activity of electrolyzed water at or near pH 2.5 was
equal to that of acidic or alkaline water (pH ca.
1
3) Nichols, R., The response of carnations (Dianthus
caryophyllus) to ethylene. J. Hort. Sci., 43, 335–349
(
1968).
1
,2)
14) Conway, J., Encyclopedia of chemical technology,
Maruzen, Tokyo, pp. 850–855 (1960).
6
–8), although these studies did not distinguish the
usefulness between the two kinds of electrolyzed
water. The results of the present study indicate that
the eŠect of these two kinds of electrolyzed water on
the vase life of cut carnations and the decomposition
rate of ethylene is distinct.
1
5) Nakagawara, S., Goto, T., Nara, M., Ozawa, Y.,
Hotta, K., and Arata, Y., Spectroscopic characteriza-
tion and the pH dependence of bactericidal activity of
the aqueous chlorine solution. Anal. Sci., 14, 691–698
(1998).
EAW might in‰uence ethylene synthesis as well as
the decomposition of ethylene generated by carna-
tion ‰owers. Further study is therefore necessary to
fully elucidate the eŠect of EAW on plants.
16) Connell, G. F., The chlorination chloramination
W
handbook, ed. American Water Works Association,
USA, pp. 25–26, 117–119 (1996).
7) Eigen, M., and Kustin, K., The kinetics of halogen
hydrolysis. J. Am. Chem. Soc., 84, 1355–1358 (1962).
8) White, C. G., Handbook of chlorination and alterna-
tive disinfectants, 4th ed., John Wiley & Sons, USA
1
1