U.S. patent application number 12/083130 was filed with the patent office on 2010-06-17 for ozone oxidation accelerator, ozone oxidation accelerator composition, and ozone treatment method.
This patent application is currently assigned to LION CORPORATION. Invention is credited to Taku Ogura, Yoshikuni Takeuchi, Masaru Tamura.
Application Number | 20100147777 12/083130 |
Document ID | / |
Family ID | 37906302 |
Filed Date | 2010-06-17 |
United States Patent
Application |
20100147777 |
Kind Code |
A1 |
Takeuchi; Yoshikuni ; et
al. |
June 17, 2010 |
Ozone Oxidation Accelerator, Ozone Oxidation Accelerator
Composition, and Ozone Treatment Method
Abstract
The present invention relates to an ozone oxidation accelerator
containing a compound of which a 0.5% by mass aqueous solution at
25.degree. C. has a dynamic surface tension at 100 msec of 70 mN/m
or less and a dynamic surface tension at 30 sec of 55 to 67 mN/m,
and an ozone oxidation accelerator composition containing the ozone
oxidation accelerator. The present invention also relates to an
ozone treatment method including a step of supplying ozone into
water to be treated that contains a substance to be treated, in the
presence of the ozone oxidation accelerator composition.
Inventors: |
Takeuchi; Yoshikuni; (Tokyo,
JP) ; Ogura; Taku; (Tokyo, JP) ; Tamura;
Masaru; (Tokyo, JP) |
Correspondence
Address: |
MERCHANT & GOULD PC
P.O. BOX 2903
MINNEAPOLIS
MN
55402-0903
US
|
Assignee: |
LION CORPORATION
TOKYO
JP
|
Family ID: |
37906302 |
Appl. No.: |
12/083130 |
Filed: |
October 5, 2006 |
PCT Filed: |
October 5, 2006 |
PCT NO: |
PCT/JP2006/319956 |
371 Date: |
April 3, 2008 |
Current U.S.
Class: |
210/760 ;
252/186.1 |
Current CPC
Class: |
C02F 2303/04 20130101;
C02F 2303/12 20130101; C02F 1/78 20130101; C11D 11/0047 20130101;
C02F 2305/04 20130101; C02F 2303/02 20130101 |
Class at
Publication: |
210/760 ;
252/186.1 |
International
Class: |
C02F 1/78 20060101
C02F001/78; C09K 3/00 20060101 C09K003/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 5, 2005 |
JP |
292408 |
Claims
1. An ozone oxidation accelerator comprising a compound of which a
0.5% by mass aqueous solution at 25.degree. C. has a dynamic
surface tension at 100 msec of 70 mN/m or less and a dynamic
surface tension at 30 sec of 55 to 67 mN/m.
2. The ozone oxidation accelerator according to claim 1, wherein
the compound has a molecular weight of 100 or greater.
3. The ozone oxidation accelerator according to claim 1, wherein
the compound has a molecular weight of 250 or less.
4. An ozone oxidation accelerator composition comprising the ozone
oxidation accelerator of claim 1.
5. An ozone treatment method for treating a substance to be treated
by ozone oxidation, the method comprising a step of supplying ozone
into water to be treated that comprises a substance to be treated,
in the presence of the ozone oxidation accelerator composition of
claim 4.
Description
TECHNICAL FIELD
[0001] The present invention relates to an ozone oxidation
accelerator that accelerates ozone oxidation and exhibits excellent
effects of bleaching, sterilization, deodorizing, decomposition,
synthesis, or the like, an ozone oxidation accelerator composition,
and an ozone treatment method.
[0002] Priority is claimed on Japanese Patent Application No.
2005-292408, filed on Oct. 5, 2005, the content of which is
incorporated herein by reference.
BACKGROUND ART
[0003] Ozone has an extremely high standard oxidation-reduction
potential at 25.degree. C. of 2.07V, and its oxidation potential is
the next strongest after fluorine. Therefore, an ozone treatment is
conventionally performed by taking advantage of this oxidation
potential in various fields of semiconductor-cleaning,
food-cleaning (sterilization), water-purification, and the
like.
[0004] In addition, since ozone produces only oxygen by
decomposition thereof, and therefore ozone is environmentally
friendly, use of ozone has tended to increase in recent years.
[0005] A method for improving effects of such an ozone treatment
usually involves increasing the amount of ozone used. However, an
increase of the amount of ozone used directly leads to an increase
in treatment cost. In addition, the amount of non-utilized
de-absorbed ozone, that is, ozone released in air without being
absorbed in water when performing the treatment while supplying
ozone into water, will be increased. An increase of de-absorbed
ozone not only leads to an increase in cost required for the
treatment but also heightens concern about work safety. In Japan
and many other countries, in regard to the ozone concentration, a
value of 0.1 ppm (=0.2 mg/m.sup.3) is employed as a work
environment standard considering work safety. Thus, there is a
limit to increasing the amount of ozone used.
[0006] For solving such problems, Patent Document 1 discloses a
sterilizing method including the use of ozone together with
hydrogen peroxide as a method for obtaining a high treatment effect
while reducing the amount of ozone used. Patent Document 2
discloses a sterilizing method including immersing food alternately
into an ozone solution and an organic acid solution and/or an
alcohol solution.
[0007] However, these methods require another treatment step to be
performed in addition to the step of treating with ozone, and thus
the process becomes complicated.
[0008] Further, as the method for improving efficiency of the ozone
treatment, a method of using ozone with an organic substance has
been proposed.
[0009] For example, Patent Document 3 discloses a germicidal
detergent composition containing ozone and a surfactant, the
germicidal detergent composition enhancing germicidal effects when
the substance to be treated is immersed therein. The germicidal
detergent composition is intended to supplement washing effects on
oily components with a surfactant, and also to employ the residual
effect of ozone.
Patent Document 1: Japanese Unexamined Patent Application, First
Publication No. H11-226579 Patent Document 2: Japanese Unexamined
Patent Application, First Publication No. H3-164155 Patent Document
3: Japanese Unexamined Patent Application, First Publication No.
H6-313194
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0010] As the method of ozone treatment, a method of supplying
(aerating) ozone (gas) into water to be treated containing a
substance to be treated (ozone aeration treatment), or a method of
immersing a substance to be treated in an ozone solution in which
ozone is dissolved therein (ozone water immersion treatment) as
disclosed in Patent Document 2 or 3, may be usually adopted. Among
them, the ozone aeration treatment has advantages in that a small
amount of ozone is used, a small amount of water is used, the
treatment can be performed even if the amount of an organic
substance to be treated is large, and the like, as compared to the
ozone water immersion treatment.
[0011] However, in the case where the ozone aeration treatment is
performed, it is difficult to improve the efficiency of ozone
treatment with the method disclosed in Patent Document 3. For
example, if a surfactant is present in water to be treated,
bubbling on the water surface occurs upon aeration, and accordingly
overflow or the like may occur, and thus the treatment efficiency
may be lowered or it may become impossible to carry out the
treatment at all. In addition, ozone may act on the surfactant in
water to be treated and accordingly the amount of ozone that acts
on a substance to be treated decreases, thereby reducing the
efficacy of ozone treatment. In particular, in the case where an
ozone aeration treatment is performed at a low concentration as
mentioned above in consideration of work safety, the ozone
treatment efficiency is extremely poor.
[0012] The present invention is made under these circumstances, and
an object thereof is to provide an ozone oxidation accelerator, an
ozone oxidation accelerator composition, and an ozone treatment
method, by which bubbling on the water surface can be controlled
and ozone oxidation can be simply accelerated in an ozone aeration
treatment particularly at a low concentration.
Means for Solving the Problems
[0013] The present inventors have carried out extensive studies to
achieve the above-mentioned object, and as a result, the present
inventors have found that the above-mentioned problem can be solved
by using a compound having specific properties. Thus, the present
inventors have completed the invention.
[0014] That is, a first aspect of the invention is an ozone
oxidation accelerator containing a compound of which a 0.5% by mass
aqueous solution at 25.degree. C. has a dynamic surface tension at
100 msec of 70 mN/m or less and a dynamic surface tension at 30 sec
of 55 to 67 mN/m.
[0015] A second aspect of the invention is an ozone oxidation
accelerator composition containing the ozone oxidation accelerator
of the first aspect.
[0016] A third aspect of the invention is an ozone treatment method
including a step of supplying ozone into water to be treated that
contains a substance to be treated, in the presence of the ozone
oxidation accelerator composition of the second aspect.
EFFECTS OF THE INVENTION
[0017] The ozone oxidation accelerator, the ozone oxidation
accelerator composition, and the ozone treatment method according
to the present invention enable bubbling on the water surface to be
controlled in an ozone aeration treatment, particularly in an ozone
aeration treatment at a low concentration, and also enable an ozone
oxidation treatment to be easily accelerated. Therefore, a
reduction in the amount of ozone used in an ozone aeration
treatment and an increase in efficiency of the ozone aeration
treatment can be achieved according to the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] FIG. 1 is a graph showing a change in sterilization effect
over time in cases where ozone aeration is performed by changing an
ozone concentration without adding any additives and cases where
glycerin or triacetin is added in low-concentration ozone aeration
in Test Example 2.
[0019] FIG. 2 is a graph showing a sterilization effect in cases
where ozone aeration is performed by changing an ozone
concentration without adding any additives and cases where glycerin
or triacetin is added in low-concentration ozone aeration in Test
Example 2.
BEST MODE FOR CARRYING OUT THE INVENTION
Ozone Oxidation Accelerator
[0020] The ozone oxidation accelerator according to the present
invention is composed of a compound of which a 0.5% by mass aqueous
solution at 25.degree. C. has a dynamic surface tension at 100 msec
(hereinafter, also may be abbreviated as `dynamic surface tension
at 100 msec`) of 70 mN/m or less and a dynamic surface tension at
30 sec (hereinafter, also may be abbreviated as `dynamic surface
tension at 30 sec`) of 55 to 67 mN/m.
[0021] In the present specification and claims, the term `dynamic
surface tension` refers to a surface tension when a new interface
is formed or an interface is in an unstably flowing or stirred
state.
[0022] A process of forming bubbles by supplying a gas into water
through a straw is given as an example. When a gas is supplied
through a straw put diagonally in water, a hemispheric interface
(interface between water and gas) is formed from a tip of the
straw. At this time, a force trying to restore the interface
(surface tension) and a gas buoyant force are acting on the
interface. The buoyant force becomes greater in accordance with an
increase in the amount of gas in the interface. When the buoyant
force becomes greater than the surface tension, the hemispheric
interface separates from a tip of the straw and forms a bubble,
which rises up on the water surface. Bubbles are repeatedly
produced and collect on the water surface to produce foam.
[0023] At this time, the interface is in an unstable state. After
forming a bubble (after stopping the supply of a gas), the
interface becomes stable with time. The surface tension gradually
decreases in accordance with this stabilization, and becomes
uniform (equilibrium value). As such, the surface tension of a
bubble's interface after formation and before reaching an
equilibrium value (until the interface reaches in a stable state)
refers to the dynamic surface tension. The dynamic surface tension
changes with respect to each measurement time.
[0024] For the formation of bubbles, the smaller the amount of gas
supplied at the time when the buoyant force becomes greater than
the surface tension, the smaller the size of the bubbles. Also, the
smaller the equilibrium value, the higher the stability of bubbles
or foam, and thus they are hardly likely to break. Alternatively,
the greater the equilibrium value, the lower the stability of
bubbles or foam, and thus they are more likely to break.
[0025] Characteristic of bubbles generated in water to be treated
by ozone aeration is controlled by components to be blended in
water to be treated, according to the present invention, and
thereby excellent effects are achieved, as shown below.
[0026] The dynamic surface tension at 100 msec is 70 mN/m or less,
preferably 68 mN/m or less, and more preferably 65 mN/m. Although
the lower limit is not particularly limited, the dynamic surface
tension at 100 msec is preferably 55 mN/m or greater, and more
preferably 60 mN/m or greater.
[0027] Herein, the dynamic surface tension at 100 msec is a dynamic
surface tension after 100 msec from 0 msec provided that the point
where the gas supply is started is 0. Specifically, with reference
to the above example of supplying gas through a straw, the dynamic
surface tension at 100 msec is a dynamic surface tension 100 msec
after the start of gas being supplied into a straw. When the
dynamic surface tension at 100 msec is 70 mN/m or less, a buoyant
force becomes greater than the surface tension at a point where the
amount of gas supplied is small, thus a hemispheric interface
becomes separated from a tip of the straw to form bubbles.
Specifically, fine bubbles are formed.
[0028] By making the bubble size smaller, contact efficiency of
ozone with a substance to be treated is improved, and as a result,
the ozone treatment efficiency is improved.
[0029] The dynamic surface tension at 30 sec is from 55 to 67 mN/m,
preferably from 58 to 67 mN/m, and more preferably from 60 to 67
mN/m.
[0030] Herein, the dynamic surface tension at 30 sec is a dynamic
surface tension after 30 sec from 0 msec provided that the point
where the gas supply is started is 0. In general, it requires
dozens of hours for the dynamic surface tension to reach the
equilibrium value, and it is time consuming to perform its
measurement. The dynamic surface tension at 30 sec employed in the
present invention does not always equal to the equilibrium value,
but considering the treatment time when the aeration treatment is
performed, the dynamic surface tension at 30 sec is useful as an
index to evaluate the stability of bubbles or foam.
[0031] When the dynamic surface tension at 30 sec is within the
range of 55 to 67 mN/m, the formed bubbles shows an appropriate
stability.
[0032] Meanwhile, when the dynamic surface tension at 30 sec is
less than 55 mN/m, the bubbles become so stable that the surface of
water foams during the aeration treatment thereby causing overflow
or the like, thus the treatment becomes difficult. When the dynamic
surface tension at 30 sec is more than 67 mN/m, the ozone treatment
efficiency becomes poor. The reason is assumed to be that the
stability of bubbles is low and thus the bubbles break up before
contact with a substance to be treated.
[0033] The dynamic surface tension at 100 msec and the dynamic
surface tension at 30 sec may be determined by measuring those of a
0.5% by mass aqueous solution (25.degree. C.) prepared by
dissolving the compound in water using a commercially available
dynamic tensiometer, such as SITA t60 (trade name) manufactured by
EKO INSTRUMENTS Co., Ltd., for example.
[0034] The ozone oxidation accelerator according to the present
invention has a molecular weight of preferably 100 or greater, more
preferably 120 or greater. If the compound has a molecular weight
of 100 or greater, the dynamic surface tension at 30 sec is more
likely to give a value of 67 mN/m or less, thus being preferable
for the present invention. In addition, it is hardly volatile, and
thus hardly causes various problems due to the volatilization.
[0035] The ozone oxidation accelerator according to the present
invention has a molecular weight of preferably 250 or less, more
preferably 200 or less.
[0036] If the compound has a molecular weight of 250 or less, the
dynamic surface tension at 100 msec is more likely to give a value
of 70 mN/m or less because of a rapid spread of molecules in an
interface of bubbles. The dynamic surface tension at 30 sec is more
likely to give a value of 55 mN/m or greater thereby hardly causing
a foam to form, thus being preferable for the present
invention.
[0037] However, although the molecular weight is 250 or less, a
molecule with high hydrophobicity is likely to appear as having a
large molecular weight by association. Therefore, the ozone
oxidation accelerator according to the present invention is
preferably a compound with low hydrophobicity. Examples of the
compound with low hydrophobicity include compounds having a polar
group such as a carboxy group or a hydroxyl group (e.g., carboxylic
acid, alcohol, etc.), and compounds including an oxygen atom in the
structure (e.g., ester, ether, etc.).
[0038] The ozone oxidation accelerator according to the present
invention is not particularly limited as long as the
above-mentioned dynamic surface tension conditions are satisfied,
and specific examples thereof include organic acids and salts
thereof (hereinafter, these are together referred to as `organic
acid (salt)`), ketone, alcohol, ether, ester, and the like.
[0039] Examples of the organic acid (salt) include carboxylic
acids, sodium salts thereof, potassium salts thereof, ammonium
salts thereof, and the like. The carboxylic acid (salt) has
preferably 7 to 10, more preferably 7 to 9, and even more
preferably 8 or 9 carbon atoms. Specific examples thereof include
2-ethylhexanoic acid, heptanoic acid, octanoic acid, nonanoic acid,
salts thereof, and the like. Among these, preferred is an
octanoate, particularly preferred is sodium octanoate.
[0040] Examples of the alcohol include pentanediol,
2-methyl-2,4-pentanediol, diacetone alcohol,
3-methyl-1,3-butanediol, 2-methyl-1,3-butanediol,
3-methyl-1,4-butanediol, 2-methyl-1,4-butanediol,
2-methyl-1,2-butanediol, 3-methyl-1,2-butanediol, and the like.
[0041] Examples of the ketone include acetylacetone and the
like.
[0042] Preferable examples of the ether include ether compounds of
glycols (ethylene glycol, polyethylene glycol, propylene glycol,
polypropylene glycol, etc.). Specific examples thereof include
diethyleneglycol monoalkylether or dialkylether, such as
diethyleneglycol diethylether, diethyleneglycol dimethylether,
diethyleneglycol monomethylether, and diethyleneglycol
monobutylether; propyleneglycol monoalkylether or dialkylether,
such as propyleneglycol monoethylether and propyleneglycol
monobutylether; dipropyleneglycol monoalkylether or dialkylether,
such as dipropyleneglycol monoethylether, dipropyleneglycol
monobutylether, dipropyleneglycol monopropylether, and
dipropyleneglycol monomethylether; etc.
[0043] Examples of the ester include carboxylic acid ester,
sulfuric acid ester, phosphoric acid ester, boric acid ester, and
the like.
[0044] The carboxylic acid ester is a compound having at least one
structure represented by `C--CO--O--C` in the molecule.
[0045] As a carboxylic acid for the carboxylic acid ester, those
exemplified for the organic acid as above can be mentioned.
[0046] In the present invention, an ester compound represented by
the following general formula (I) is particularly preferable.
##STR00001##
[0047] In the formula, x is 0 to 4; and R.sup.1, R.sup.2, and
R.sup.3, are each independently represents a group selected from
the group consisting of --H, --OH, a group represented by the
following general formula (1), and a group represented by the
following general formula (2), while at least one of R.sup.1,
R.sup.2, and R.sup.3 is a group represented by the following
general formula (2):
##STR00002##
[0048] In the formulae, R.sup.4 is an alkyl group having 1 to 4
carbon atom(s).
[0049] In the formula (1), x is 0 to 4, preferably 1.
[0050] R.sup.1, R.sup.2, and R.sup.3, are each independently a
group selected from the group consisting of --H, --OH, a group
represented by the above general formula (1) (hereinafter, referred
to as Group (1)), and a group represented by the above general
formula (2) (hereinafter, referred to as Group (2)), while at least
one of R.sup.1, R.sup.2, and R.sup.3 is Group (2).
[0051] When one or two of R.sup.1, R.sup.2, and R.sup.3 is/are a
group other than Group (2), the group is particularly preferably
--OH.
[0052] In the formulae (1) and (2), R.sup.4 is an alkyl group
having 1 to 4 carbon atom(s), and examples thereof include a methyl
group, an ethyl group, an n-propyl group, an isopropyl group, an
n-butyl group, a sec-butyl group, an iso-butyl group, and a
tert-butyl group. R.sup.4 is preferably a methyl group or an ethyl
group, and particularly preferably a methyl group.
[0053] As the compound represented by the general formula (1),
particularly preferred are glyceryl monoacetate (monoacetin) in
which x is 1, and one of R.sup.1, R.sup.2, and R.sup.3 is a group
represented by the formula (2) in which R.sup.4 is a methyl group
while the other two are --OH; glycerol diacetate (diacetin) in
which x is 1, and two of R.sup.1, R.sup.2, and R.sup.3 are
represented by the formula (2) in which R.sup.4 is a methyl group
while the other one is --OH; and glyceryl triacetate (triacetin) in
which x is 1, and all of R.sup.1, R.sup.2, and R.sup.3 are a group
represented by the formula (2) in which R.sup.4 is a methyl
group.
[0054] There are structural isomers of monoacetin and diacetin. The
structural isomer of monoacetin can be exemplified by
glycerine-1-acetate, glycerine-2-acetate, or glycerine-3-acetate.
The structural isomer of diacetin can be exemplified by
glycerine-1,3-diacetate or glycerine-1,2-diacetate.
[0055] In addition to the above-mentioned compounds, the compound
represented by the general formula (1) can be further exemplified
by monobutyrin, propyl acetate, diacetoxy propane (propanediol
diacetate), diacetoxy butane (butanediol diacetate), or the
like.
[0056] Examples of the ester other than the compound represented by
the general formula (I) include the following:
[0057] (1) esters obtained by acetylating a hydroxyl group in any
of polyethylene glycol such as diethylene glycol and mono- or
dialkylether thereof, and polypropylene glycol such as dipropylene
glycol and mono- or dialkylether thereof, such as, for example,
diethyleneglycol diacetate, diethyleneglycol monoethylether
acetate, and the like;
[0058] (2) methyl, ethyl, propyl, or butylester of malic acid,
citric acid, oxalic acid, malonic acid, succinic acid, maleic acid,
glutaric acid, or adipic acid, such as, for example, dimethyl
succinate, and the like;
[0059] (3) alkylene carbonate such as butylene carbonate, hexylene
carbonate, and dibutylcarbonate, or alkyl lactone, such as, for
example, pentano-4-lactone, .gamma.-decalactone,
.epsilon.-decalactone, and .gamma.-nonalactone; and
[0060] (4) 1-ethoxy-2-propanol acetate, and the like.
[0061] The ozone oxidation accelerator according to the present
invention may be composed of a single kind of those compounds or a
mixture of two or more kinds thereof.
[0062] As described above, since the ozone oxidation accelerator
according to the present invention is a compound having a dynamic
surface tension at 100 msec of 70 mN/m or less and a dynamic
surface tension at 30 sec of 55 to 67 mN/m or less, the ozone
oxidation can be accelerated. Accordingly, a reduction in the
amount of ozone used in an ozone treatment and a high level of
efficiency can be achieved.
[0063] The above realized because when the dynamic surface tension
satisfies the above-mentioned conditions, fine ozone bubbles with
an appropriate stability are formed while supplying ozone
(aeration) into water containing the ozone oxidation
accelerator.
[0064] That is, when the dynamic surface tension at 100 msec is 70
mN/m or less, fine ozone bubbles are formed. Due to the reduction
in size of the bubbles, the dissolution efficiency of ozone and
contact efficiency of ozone with a substance to be treated are
improved.
[0065] Further, when the dynamic surface tension at 30 sec is
within the range of 55 to 67 mN/m, bubble forms have an appropriate
stability that it is stable until contact is made with a substance
to be treated, and then break up in a relatively short period of
time.
[0066] Accordingly, it is assumed that due to these synergistic
effects, the contact efficiency of ozone with a substance to be
treated is improved thereby accelerating the ozone oxidation, and
the formation of a foam on the water surface is controlled.
Ozone Oxidation Accelerator Composition
[0067] The ozone oxidation accelerator composition according to the
present invention is a composition containing the ozone oxidation
accelerator according to the present invention described above.
[0068] The proportion of the ozone oxidation accelerator in the
ozone oxidation accelerator composition according to the present
invention is within the range of preferably 0.1 to 100% by mass,
and more preferably 10 to 100% by mass, relative to the total mass
of solid contents of the zone oxidation accelerator composition. If
the proportion is 0.1% by mass or more, the further excellent
effects of oxidation acceleration are exhibited.
[0069] The ozone oxidation accelerator composition according to the
present invention may further contain other components for the
purpose of providing usability, stabilization of the product, and
imparting function, within the scope of not interfering with the
ozone oxidation reaction. Examples of the components that may be
included include various surfactants, chelating agents, flavors,
enzymes, fluorescent agents, alkaline agents, viscosity improvers,
dispersants, inorganic salts, alcohols, saccharides, acids, and the
like.
[0070] The surfactant is not particularly limited, and can be
appropriately selected from well-known surfactants depending on the
purpose. Such surfactants can be exemplified by the following (1)
to (4):
[0071] (1) anionic surfactants such as water-soluble salts of alkyl
benzene sulfonate, alkyl sulfate, alkyl phenyl ether sulfate,
polyoxyethylene alkyl ether sulfate, acylamido alkyl sulfate, alkyl
phosphate, polyoxyethylene alkyl ether carboxylate, paraffin
sulfonate, .alpha.-olefin sulfonate, .alpha.-sulfocarboxylate, and
esters thereof, and soap;
[0072] (2) nonionic surfactants such as ethoxylated nonions e.g.,
polyoxyalkylether, polyoxyalkylphenyl ether, etc; sugar-based
active agents e.g., polyglycerin fatty acid ester, glycerin fatty
acid ester, propylene glycol fatty acid ester, sorbitan fatty acid
ester, polyoxyethylene sorbitan fatty acid ester, glycoside ester,
sugar ester, methyl glycoside ester, ethyl glycoside ester,
alkylpolyglycoside, etc; and amide-based active agents e.g., alkyl
amine oxide, alkyl diethanol amide, fatty acid N-alkyl glucamide,
etc;
[0073] (3) amphoteric surfactants such as amino carboxylate e.g.,
alkylcarboxybetaine, alkylsulfoxybetaine, alkylamidepropylbetaine,
alkylalaninate, etc; imidazoline derivatives; and alkylamineoxide;
and
[0074] (4) cationic surfactants such as alkyltrimethyl ammonium
salt and dialkyldimethyl ammonium salt.
[0075] The surfactant may be composed of a single kind thereof or
plural kinds thereof.
[0076] When ozone is aerated in water to be treated containing a
high concentration of surfactant, there may be a case where an
undesired phenomenon occurs upon the process such as overflow due
to a foaming of the water surface. Thus, the content of a
surfactant in the ozone oxidation accelerator composition is
preferably determined considering the concentration of a surfactant
in water to be treated. According to the present invention, the
content of a surfactant is preferably from 0 to 10% by mass, more
preferably from 0 to 5% by mass, relative to the total solid
content of the ozone oxidation accelerator composition. If the
content is 10% by mass or less, the concentration of a surfactant
in water to be treated becomes a level not causing a foaming
problem upon the use of the ozone oxidation accelerator
composition.
[0077] The chelating agent refers to an agent that holds polyvalent
metal ions when the compound is dissolved in water.
[0078] The chelating agent may be any of those capable of holding
polyvalent metal ions when dissolved in water. The agent is not
particularly limited, and specific examples thereof include
phosphorous compounds, compounds having at least two carboxyl
groups, and the like. Preferred are phosphoric acid, metaphosphoric
acid, hexametaphosphoric acid, pyrophosphoric acid,
tripolyphosphoric acid, 1-hydroxyethane-1,1-diphosphonic acid,
triethylenetetramine-N,N, N', N', N''', N''', N'''-hexaacetate,
diethylenetriamine pentaacetate, ethylenediamine tetraacetate,
nitroso triacetate, oxalic acid, and citric acid; more preferred
are hexametaphosphoric acid, pyrophosphoric acid, tripolyphosphoric
acid, 1-hydroxyethane-1,1-diphosphonic acid, diethylenetriamine
pentaacetate, ethylenediamine tetraacetate, and nitroso triacetate;
and even more preferred are hexametaphosphoric acid,
tripolyphosphoric acid, 1-hydroxyethane-1,1-diphosphonic acid,
diethylenetriamine pentaacetate, ethylenediamine tetraacetate, and
nitroso triacetate.
[0079] The chelating agent may be composed of a single kind thereof
or plural kinds thereof.
[0080] The content of a chelating agent in the ozone oxidation
accelerator composition is preferably 0 to 40% by mass, more
preferably 0 to 10% by mass, relative to the total solid content of
the ozone oxidation accelerator composition.
Ozone Oxidation Treatment Method
[0081] The ozone treatment method of the present invention is a
method of treating a substance to be treated by ozone oxidation.
The method is characterized by including a step of supplying ozone
(aeration) into water to be treated containing a substance to be
treated, in the presence of the ozone oxidation accelerator
composition.
[0082] The substance to be treated is not particularly limited, and
generally those subjected to an ozone treatment may be used.
Specific examples of the substance to be treated include substances
to be subjected to an ozone treatment for bleaching, sterilization,
cleaning, deodorizing, decomposition, synthesis, or the like, such
as organic substances e.g., dye, bacteria, oils and fats, amines,
proteins, humus, sludge, surfactant, pesticide, etc., and products
to which such an organic substance is adhered (semiconductors,
foods, etc.).
[0083] The concentration of the ozone oxidation accelerator
composition in water to be treated is in a level for the
concentration of the ozone oxidation accelerator to be within the
range of preferably 0.001 to 5% by mass, more preferably 0.01 to 1%
by mass. When the concentration of the ozone oxidation accelerator
is 0.001% by mass or more, the effect of the present invention is
high. When the concentration is 5% by mass or less, consumption of
ozone due to reaction with an ozone oxidation accelerator in water
to be treated is controlled, and thereby efficiency of the ozone
treatment is improved.
[0084] Ozone reacts with dissolution metals, chlorine, or organic
substances due to its strong oxidation potential, and therefore
water containing a less amount of such impurities (highly pure)
such as ultrapure water having a resistivity of 0.00001 M.OMEGA. or
greater, more preferably 0.001 M.OMEGA. or greater, even more
preferably 1 M.OMEGA. or greater, is useful for the reaction, and
thus is preferable as the water to be treated.
[0085] The aeration can be carried out, for example, by charging
water to be treated containing the ozone oxidation accelerator
composition and a substance to be treated, into a container, and
then supplying a gas (aeration gas) containing at least ozone into
the water to be treated. Alternatively, the ozone oxidation
accelerator composition may be added in water to be treated while
supplying an aeration gas into the water to be treated.
[0086] In the present process, an agitating device or the like may
also be used to stir water to be treated during the aeration.
[0087] It is preferable that the container (treatment container) in
which water to be treated is held and aeration is to be carried out
has a surface made of materials such as a glass, TEFLON
(polytetrafluoroethylene) (trademark), titanium, ozone-treated
(forming a strong oxide film by ozone of high concentration)
aluminum or stainless steel, on the side to be in contact with the
water to be treated, because the oxidation potential of ozone is
strong.
[0088] If a container made of a material such as nitrile rubber,
silicon, or urethane, which are low in resistance to ozone, is
used, it is necessary to pay full attention to deterioration of the
treatment container.
[0089] As the aeration gas, generated ozone may be directly used,
or may be diluted with a diluent gas for supply.
[0090] The generation method of ozone is not limited, and examples
thereof include a method of irradiating oxygen with light of high
energy such as electron rays, radioactive rays, or ultraviolet
light, a chemical method, an electrolytic process, a discharge
method, and the like. A silent discharge method is industrially
used in many cases from the viewpoints of cost and generation
amount.
[0091] A commercially available ozone generator may be used to
generate ozone. For example, a low-concentration ozone generator
BO-90 (trade name) manufactured by Bethel Co., Ltd., is
commercially available, and a high-concentration ozone generator
HO-100 (trade name) manufactured by Navi Engineering Co. Ltd., is
commercially available.
[0092] Since ozone has a self-decomposition property, it is
desirable to be used immediately after being prepared.
[0093] The diluent gas for a use in dilution of ozone is preferably
a gas inert or poorly reactive to ozone, such as helium, argon,
carbon dioxide, oxygen, air, or nitrogen.
[0094] The concentration of ozone in the aeration gas is not
particularly limited, but is preferably 10% by mass or less, more
preferably 1% by mass or less, in view of work safety. The lower
limit is not particularly limited, but is preferably 0.000001% by
mass or more, more preferably 0.0001% by mass or more, considering
an ozone treatment efficiency or the like. The present invention is
useful particularly when the ozone concentration is low, for
example, within the range of 0.0001 to 0.5% by mass, since the
oxidation of ozone can be effectively accelerated.
[0095] A method of aerating the aeration gas into water to be
treated is not particularly limited, and methods conventionally
adopted, such as method in which a diffusion plate, a diffusion
cylinder, a diffuser, or the like, is used, can be adopted.
[0096] The treatment temperature (that is, temperature of water to
be treated) during the aeration is not particularly limited, but it
is preferable that the treatment temperature be 80.degree. C. or
below. If the treatment temperature is 80.degree. C. or below,
ozone hardly decomposes, and solubility of ozone in water to be
treated also becomes high. The treatment temperature is more
preferably 0 to 60.degree. C., even more preferably 0 to 30.degree.
C.
[0097] pH of water to be treated during the aeration is not
particularly limited. However, decomposition of ozone or
decomposition of the accelerator tends to occur and thus attention
is required under a high alkaline condition, for example at pH of
12 or higher, pH of water to be treated is more preferably 1 to 10,
even more preferably 2 to 8.
[0098] The treatment time (time for performing aeration) during the
aeration is not particularly limited, and it may be determined in
view of a treatment purpose, ease of decomposition of a substance
to be treated, a concentration of a substance to be treated in
water to be treated, a temperature, a volume for treatment, or the
like.
[0099] In the process, together with the aeration treatment, an
advanced oxidation process (AOP) may also be carried out to rapidly
process bleaching or decomposition of a persistent substance.
[0100] AOP is a process advancing an oxidation reaction by actively
decomposing ozone to generate a hydroxyl radical which has a strong
oxidation potential.
[0101] Irradiation of ultraviolet rays, adoption of high pH
conditions, addition of H.sub.2O.sub.2 or inorganic catalyst, or
the like is usually adopted to actively decompose ozone.
EXAMPLES
[0102] In the following, the present invention will be described in
more detail with reference to Examples, but Examples are not
supposed to limit characteristics of the present invention.
Test Example 1
[0103] Compounds shown in Table 1 below were measured in terms of
the dynamic surface tension at 100 msec and the dynamic surface
tension at 30 sec of a 0.5% by mass aqueous solution at 25.degree.
C. in accordance with the following procedure.
[0104] Compounds shown in Table 1 were each dissolved in water to
prepare a 0.5% by mass aqueous solution (25.degree. C.), and the
dynamic surface tension at 100 msec and the dynamic surface tension
at 30 sec of each aqueous solution were measured with SITA t60
manufactured by EKO INSTRUMENTS Co., Ltd. As water, ultrapure water
having a resistivity of 18 M.OMEGA. or greater which was obtained
by purification with GSR-210 manufactured by ADVANTEC was used.
[0105] The results and the molecular weight of each compound are
shown in Table 1.
TABLE-US-00001 TABLE 1 Dynamic Surface Dynamic Molecular Tension
Surface Tension Compound Weight (100 msec) [mN/m] (30 sec) [mN/m]
Example 1 Monoacetin 134.1 69.8 66.6 Example 2 Diacetin 176.2 66.8
61.9 Example 3 Triacetin 218.2 61.7 61.5 Example 4
1,2-propyleneglycol 160.2 60.6 60.0 diacetate Example 5 monobutylin
162.2 64.0 62.2 Example 6 1-ethoxy-2-propanol 146.2 57.2 55.0
acetate Example 7 n-propyl acetate 102.1 55.6 55.5 Example 8
1,4-butanediol 174.2 59.1 57.8 diacetate Example 9 sodium octanoate
166.2 67.7 66.4 Comparative Sodium lauryl sulfate* 288.4 38.9 36.2
Example 1 Comparative C12EO15* 847.1 40.9 37.2 Example 2
Comparative C12EO40* 1948.5 45.0 40.8 Example 3 Comparative Sucrose
stearate ester* 608.8 70.9 51.8 Example 4 Comparative Sucrose
laurate ester* 524.6 40.8 35.2 Example 5 Comparative Glycerin 218.3
26.4 22.5 Example 6 monocaprate* Comparative Glycerin 246.4 29.2
22.2 Example 7 monocaprylate* Comparative Decaglycerin 941.1 67.1
39.0 Example 8 monolaurate* Comparative Sodium acetate 82.0 72.0
72.0 Example 9 Comparative Sodium hexanoate 138.0 69.1 68.5 Example
10 Comparative Ethanol 46.1 69.4 69.0 Example 11 Comparative
Glycerin 92.1 72.3 72.1 Example 12 Comparative Propylene glycol
76.1 70.2 70.0 Example 13 Comparative Triethylene glycol 150.2 70.5
70.1 Example 14 Comparative Propylene carbonate 102.1 69.7 68.9
Example 15 In Table 1, compounds with * represent commercially
available surfactants, and the following products were used,
respectively. Sodium lauryl sulfate: for biological chemistry
(manufactured by Wako Pure Chemical Industries, Ltd.) C12EO15: POE
(15) lauryl ether (lauryl ether of polyoxyethylene (average
addition mole number of 15)) (synthesis product: a product obtained
by a method described in Japanese Unexamined Patent Application,
First Publication No. H1-164437, Japanese Laid-Open Patent
Application, No. 2000-61304, etc., which has a narrow rate of 55%
or more, the narrow rate being defined in Japanese Laid-Open Patent
Application, No. 2001-164298.) C12EO40: POE (40) lauryl ether
(lauryl ether of polyoxyethylene (average addition mole number of
40)) (synthesis product: a product obtained by a method described
in Japanese Unexamined Patent Application, First Publication No.
H1-164437, Japanese Laid-Open Patent Application, No. 2000-61304,
etc., which has a narrow rate of 30% or more, the narrow rate being
defined in Japanese Laid-Open Patent Application, No. 2001-164298.)
Sodium sucrose stearate: S-1670 (manufactured by Mitsubishi-Kagaku
Foods Corporation.) Sodium sucrose laurate: L-1695 (manufactured by
Mitsubishi-Kagaku Foods Corporation.) Glycerin monocaprate:
manufactured by Riken Vitamin Co., Ltd. Glycerin monocaprylate:
manufactured by Riken Vitamin Co., Ltd. Decaglycerin monolaurate:
Decaglyn1-L (manufactured by Nikko Chemicals Co., Ltd.)
[0106] Next, the following tests were carried out using the
compounds shown in Table 1.
The results are shown in Table 2.
<Foaming Test>
[0107] 200 mL of a 0.5% by mass aqueous solution prepared in the
above manner was put in a 300 mL tall beaker, and an air having an
ozone concentration of 5 g/Nm.sup.3 was aerated through a
dispersion tube at a gas flow rate of 1.0 L/min at 25.degree. C.
for 10 minutes. As the dispersion tube, KINOSHITA-type
fritted-glass filter 503G No. 1 (coarse) manufactured by
KINOSHITARIKA was used.
[0108] After the aeration, a case where foam overflows from the
tall beaker is shown as x and a case where foam does not overflow
is shown as O.
[0109] At this time, height (cm) of the foam was also measured.
<Bleaching Test 1>
[0110] A sample solution was prepared by adding dye to be bleached
to 200 mL of a 0.5% by mass aqueous solution prepared in the above
manner so that the dye concentration is 0.5 mmol/L. As the dye to
be bleached, Acid Black 48 (molecular weight Mw of 459.46)
manufactured by ACROS was used.
[0111] 200 mL of each sample solution was put in a 300 mL tall
beaker, and an air having an ozone concentration of 5 g/Nm.sup.3
was aerated through a dispersion tube at a gas flow rate of 1.0
L/min at 25.degree. C. for 1 hour. As the dispersion tube,
KINOSHITA-type fritted-glass filter 503G No. 1 (coarse)
manufactured by KINOSHITARIKA was used.
[0112] After the reaction was ended, an absorbance at 600 nm of
each sample solution was measured using an ultraviolet visible
absorptiometer, and a dye decomposition rate was calculated with
the following formula.
[0113] Dye Decomposition Rate (%)=(initial absorbance-absorbance
after the reaction)/initial absorbance.times.100
[0114] Those giving a dye decomposition rate of 70% or more are
suited for an ozone oxidation accelerator.
[0115] A solution free from compounds other than the dye to be
bleached was used as a control sample to perform a bleaching test
with ozone alone in the same manner. The dye decomposition rate
thus obtained was 61%.
TABLE-US-00002 TABLE 2 Foaming Test Bleaching Test Height of foam
Dye decomposition Compound Overflow after 10 minutes (cm) rate (%)
Example 1 Monoacetin .smallcircle. 0.5 74 Example 2 Diacetin
.smallcircle. 0.6 80 Example 3 Triacetin .smallcircle. 1.5 89
Example 4 1,2-propyleneglycol .smallcircle. 1.4 90 diacetate
Example 5 monobutylin .smallcircle. 1.3 78 Example 6
1-ethoxy-2-propanol .smallcircle. 1.5 85 acetate Example 7 n-propyl
acetate .smallcircle. 1.5 85 Example 8 1,4-butanediol diacetate
.smallcircle. 1.5 93 Example 9 Sodium octanoate .smallcircle. 1.3
74 Comparative Sodium lauryl sulfate* x >6.5 Unmeasurable
Example 1 Comparative C12EO15* x >6.5 Unmeasurable Example 2
Comparative C12EO40* x >6.5 Unmeasurable Example 3 Comparative
Sucrose stearate ester* x >6.5 Unmeasurable Example 4
Comparative Sucrose laurate ester* x >6.5 Unmeasurable Example 5
Comparative Glycerin monocaprate* x >6.5 Unmeasurable Example 6
Comparative Glycerin x >6.5 Unmeasurable Example 7
monocaprylate* Comparative Decaglycerin x >6.5 Unmeasurable
Example 8 monolaurate* Comparative Sodium acetate .smallcircle. 0.4
50 Example 9 Comparative Sodium hexanoate .smallcircle. 0.4 62
Example 10 Comparative Ethanol .smallcircle. 0.4 65 Example 11
Comparative Glycerin .smallcircle. 0.4 48 Example 12 Comparative
Propylene glycol .smallcircle. 0.4 48 Example 13 Comparative
Triethylene glycol .smallcircle. 0.4 45 Example 14 Comparative
Propylene carbonate .smallcircle. 0.4 60 Example 15
[0116] From the results in Tables 1 and 2, it was confirmed that
when the compounds (Examples 1 to 9) having the dynamic surface
tension at 100 msec of 70 mN/m or less and the dynamic surface
tension at 30 sec of from 55 to 67 mN/m were used, overflow during
the aeration was prevented and excellent bleaching effects were
achieved, and that these compounds accelerated the ozone
oxidation.
[0117] On the other hand, when the compounds (Comparative Examples
1 to 8) having the dynamic surface tension at 30 sec of less than
55 mN/m were used, overflow of foam was caused. In the examples in
which such compounds were employing, the treatment was not
sufficiently carried out due to the overflow, and the dye
decomposition rate could not be measured.
[0118] In addition, when the compounds (Comparative Examples 9 to
15) having the dynamic surface tension at 100 msec of more than 70
mN/m or the dynamic surface tension at 30 sec of more than 67 mN/m
were used, low dye decomposition rates were obtained.
<Bleaching Test 2>
[0119] As the test solutions, Test Solution a composed of ultrapure
water having a resistivity of 18 M.OMEGA. or greater, prepared by
purification with GSR-210 manufactured by ADVANTEC, and Test
Solution b prepared by dissolving triacetin in the ultrapure water
in a concentration of 0.5% by mass, were prepared. To each of Test
Solutions a and b, Acid Black 48 dye (0.5 mmol/L) was added as a
dye to be bleached, and Bleaching Test 2 was performed. Bleaching
Test 2 was carried out in the same manner as in Bleaching Test 1,
except that 400 mL of each test solution was put in a 1,000 mL
Teflon (trade name) pot, OZSD-3000A (manufactured by Ebara Jitsugyo
Co., Ltd.) was used as an ozone generator, and an air having an
ozone gas concentration 10 times the concentration before (50
g/Nm.sup.3) was supplied to each solution through a dispersion tube
at a flow rate of 1.0 L/min at 25.degree. C. for 3 minutes. Since
an ozone gas of high concentration is used in the present test,
waste ozone gas was passed through an ozone decomposer to make it
harmless.
TABLE-US-00003 TABLE 3 Dye Decomposition Rate Test Solution a 85%
Test Solution b 99%
[0120] It was revealed from the results shown in Table 3 that the
dye decomposition acceleration effect was still be obtained by the
presence of triacetin even if an ozone gas of high concentration
was used.
Test Example 2
[0121] <Preparation of general Bacterial Solution>
[0122] 20 g of a commercially available non-bleached sprout was put
in a homogenizer bag with a filter, and 90 mL of phosphate buffered
saline was added thereto. The mixture was subjected to disruption
for 60 seconds with a homogenizer (SH-IIM manufactured by ELMEX),
and the thus obtained disrupted solution was filtered through a
filter provided to the homogenizer bag manufactured by Atect
Corporation. The filtered disrupted solution was used as a general
bacterial solution.
<Sterilization by Aeration>
[0123] As the test solutions, Test Solution a composed of ultrapure
water having a resistivity of 18 M.OMEGA. or greater, prepared by
purification with GSR-210 manufactured by ADVANTEC, Test Solution b
prepared by dissolving triacetin in the ultrapure water in a
concentration of 0.5% by mass, and Test Solution c prepared by
dissolving glycerin in the ultrapure water in a concentration of
0.5% by mass, were prepared.
[0124] 6 mL of the above-mentioned general bacterial solution was
added to 594 mL of each of Test Solutions a to c to prepare a total
of 600 mL of Sample A (Test Solution a+bacterial solution), Sample
B (Test Solution a+bacterial solution), Sample C (Test Solution
b+bacterial solution), and Sample D (Test Solution c+bacterial
solution). The thus prepared samples were used in the
experiment.
[0125] In the experiment, Sample A was put in a treatment container
(1,000 mL beaker of PYREX(trademark) glass), ozone gas was
generated with the high-concentration ozone generator described
below, and the ozone aeration was carried out at 25.degree. C.
using a dispersion tube while performing stirring with a TEFLON
(trademark) stirrer at a rotary rate of 200 rpm by varying the
aeration time (1 min, 5 mins, 10 mins). As the dispersion tube,
KINOSHITA-type fitted glass filter 503G No. 1 (coarse) manufactured
by KINOSHITARIKA was used.
[0126] Samples B to D were subjected to the ozone aeration in the
same manner as above, except that a low-concentration ozone
generator described below was used instead of the
high-concentration ozone generator.
[0127] High-concentration ozone generator: HO-100 manufactured by
Navi Engineering Co., Ltd. (flow rate: 1.0 L/min, ozone
concentration: 5 g/m.sup.3)
[0128] Low-concentration ozone generator: BO-90 manufactured by
Bethel Co., Ltd. (flow rate: 2.1 L/min, ozone concentration: 0.7
g/m.sup.3)
<Measurement of Bacterial Count>
[0129] Each of the above-mentioned Samples A to D was collected in
a test tube sterilized in advance immediately after the aeration,
and diluted in steps of 10 fold in test tubes using a peptone
saline buffer solution. For the dilution, a peptone saline buffer
solution was used. 100 .mu.L of each diluent was taken with a
micropipette and dropped onto a normal agar medium in Petri Dishes.
After spreading onto the medium with each disposable streak bar,
the plates were incubated at 37.degree. C. for 24 hours for
culturing, and then the number of colonies on each Petri Dish
having at most 300 colonies was counted to determine the surviving
viable cell count (bacterial count). Two Petri Dishes were made per
each stepwise dilution for culturing, and determined bacterial
counts were averaged.
[0130] The normal agar medium, the peptone saline buffer solution,
and the phosphate buffered saline available from Atect Corporation
were used.
[0131] A graph showing results of Samples A to D was drawn with the
aeration time on a transverse axis against the bacterial count on
the vertical axis. The graph is shown in FIG. 1. As is apparent
from the graph shown in FIG. 1, when no additive (neither triacetin
nor glycerin) was formulated, the bacterial count was decreased
with the aeration time in high-concentration ozone aeration (Sample
A), but in low-concentration ozone aeration (Sample B), almost no
change in the bacterial count was observed for the first 5 minutes
of the aeration time and a slight decrease of about 1/20 was shown
at the aeration time of 10 minutes. The result reveals that the
rate of sterilization is slower in low-concentration ozone aeration
than in high-concentration ozone aeration.
[0132] In contrast, although Sample C containing 0.5% by mass of
triacetin was subjected to low-concentration ozone aeration in the
same manner as that of Sample B, the bacterial count was decreased
at the same sterilization rate as in Sample A subjected to
high-concentration ozone aeration, thus clearly confirming that the
sterilization effect is improved.
[0133] In contrast, Sample D containing 0.5% by mass of glycerin
exhibited a slow sterilization rate and almost no change in
bacterial count at 5 minutes aeration in the same manner as in
Sample B.
[0134] In FIG. 2, bacterial counts after 5 minutes aeration time
for each of Samples A to D were shown. As is apparent from the
comparison of high-concentration ozone aeration (Sample A) with
low-concentration ozone aeration (Sample B) under a no additive
added condition in FIG. 2, the bacterial count was decreased by
about 1/100 after 5 minutes of high-concentration ozone aeration as
also shown in the graph of FIG. 1 while the bacterial count showed
almost no change after 5 minutes low-concentration ozone
aeration.
[0135] In contrast, although Sample C containing 0.5% by mass of
triacetin was subjected to low-concentration ozone aeration, the
bacterial count was decreased by the same level with 5 minutes
aeration as in Sample A of high-concentration ozone aeration, thus
clearly confirming that the sterilization effect is improved.
[0136] In contrast, Sample D containing 0.5% by mass of glycerin
showed almost no change in the bacterial count with 5 minutes
aeration, in the same manner as that of Sample B.
Test Example 3
<Deodorizing Effect on Saprolegnia Smell>
[0137] Geosmin (reagent for research of natural products chemistry,
manufactured by Kanto Chemical Co., Inc.) which is a mold-smelling
substance of tap water was dispersed in ethanol (Guaranteed
Reagent, manufactured by Kanto Chemical Co., Inc.) to 100 ppm to
prepare a solution.
[0138] A new 50 mL of beaker was immersed in 1 mol/L hydrochloric
acid, then rinsed with ion-exchange water, and further immersed in
methanol (Guaranteed Reagent, manufactured by Kanto Chemical Co.,
Inc.), to remove dirt or smell from the beaker surface. In
addition, the beaker was well-rinsed with ion-exchange water, and
then dried.
[0139] 1 mL of the geosmin solution was put in the beaker, and the
solvent was volatized while applying on an inner wall of the beaker
for a use in the following test.
[0140] 40 mL of water at 80.degree. C. was added to the beaker, and
1.5 g/Nm.sup.3 of ozone gas was aerated for 10 minutes at a flow
rate of 1 L/min using KINOSHITA-type fritted-glass filter 501G No.
4 (fine) gas dispersion tube. Then, water was removed. A sample was
obtained by drying directly at a room temperature for 24 hours, and
its smell was evaluated (Test Example 3-1).
[0141] A sample was prepared in the same manner as in Test Example
3-1, except that 1,000 ppm aqueous triacetin solution was used
instead of water, and its smell was evaluated (Test Example
3-2).
[0142] A sample was prepared in the same manner as in Test Example
3-1, except that air was aerated instead of the ozone gas in the
aeration process, and its smell was evaluated (Test Example
3-3).
[0143] A sample was prepared in the same manner as in Test Example
3-2, except that air was aerated instead of the ozone gas in the
aeration process, and its smell was evaluated (Test Example
3-4).
[0144] The evaluation on smell was sensuously performed by three
examiners in accordance with the following five-graded criteria,
and the average value thereof was calculated.
[0145] 5 points: can sense extremely strong geosmin smell
[0146] 4 points: can sense quite strong geosmin smell
[0147] 3 points: can sense geosmin smell
[0148] 2 points: can sense slight geosmin smell
[0149] 1 point: cannot sense geosmin smell (almost the same as the
non-geosmin treated beaker)
TABLE-US-00004 TABLE 4 Average Value Test Example 3-1 2.3 points
Test Example 3-2 1.3 points Test Example 3-3 .sup. 5 points Test
Example 3-4 4.7 points
[0150] The results shown in Table 4 revel that a more effective
deodorizing effect can be achieved by performing the aeration using
ozone gas in the presence of triacetin than in the case of
performing the aeration using ozone alone.
INDUSTRIAL APPLICABILITY
[0151] The ozone oxidation accelerator, the ozone oxidation
accelerator composition, and the ozone treatment method, according
to the present invention, enable bubbling on the water surface to
be controlled and ozone oxidation to be simply accelerated, in an
ozone aeration treatment, and particularly in a low concentration
ozone aeration treatment. Therefore, a reduction in the amount of
ozone used in an ozone aeration treatment and a high level of
efficiency can be achieved according to the present invention.
* * * * *