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DESCRIPTION
Title of Invention
NANOCOMPOSITE AND METHOD FOR PRODUCING SAME, AND
ADSORBENT AND METHOD FOR USING SAME
Technical Field
The present invention relates to a nanocomposite obtained by allowing an
organic nanomaterial that adsorbs a chemical component included in water to
undergo composite formation with a ferromagnetic and a method for producing
the
same, and an adsorbent containing the nanocomposite and a method for using the
same.
Background Art
Along with economic development in developing countries, water
environment pollution and water shortage have become obvious and treatment for
purifying wastewater has become a very important subject. Further, in major
oil-
gas fields, production of petroleum gas has exceeded the peak, and the ratio
of
produced water produced incidentally with produced petroleum gas has
increased.
Moreover, the production amount of shale gas and oil has increased in recent
years,
and the production amount of produced water has significantly increased
together.
Hence, treatment for purifying this type of wastewater has also become a
subject of
critical importance.
Furthermore, environmental consciousness has risen to demand a higher
level of treatment for purifying wastewater. For example, chemical components
contained in produced water include harmful components such as a small amount
of
oil and gas components, hydrogen sulfide, inorganic salts, various kinds of
organic
substances, and heavy metals. These harmful components are very difficult to
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remove from produced water, and development of more effective purifying
techniques is required. Furthermore, the kinds and contents of harmful
components greatly vary depending on the region and stratum from which gas and
oil are produced, and development of highly versatile purifying techniques is
also
required.
As a technique hitherto used in treatment for purifying wastewater, there is
known a purifying treatment method using activated carbon as an adsorbent for
harmful components (see PTL 1). However, this purifying treatment method has
problems that a large amount of activated carbon is required, leading to
increase of
the disposal costs after use of the adsorbent, that the method is not
efficient because
a speed at which harmful components are separated by, for example, filtration,
is
low, and that processes for collecting and exchanging the adsorbent after
harmful
components are adsorbed are not efficient.
There is also known a purifying treatment method using a polymeric
membrane as an adsorbent for harmful components (see PTL 2). However, this
purifying treatment method has a problem that the polymeric membrane is likely
to
be clogged or deteriorate and necessitates treatment for removing components
such
as oil contents, solid contents, hydrogen sulfide, and salts as pretreatment,
so the
removing treatment for removing all of the components becomes multi-staged to
make the system inefficient and complex.
The present inventors have reported that a peptide lipid binds with a metal
ion in a water-alcohol dispersion liquid to form an organic nanotube of a
metal
complex type (see PTL 3). However, this report does study adsorption of a
metal
ion by binding in an alcohol dispersion liquid, but does not study
adsorbability in
water and adsorbability of other chemical components than heavy metals.
Besides,
this report does not study, for example, a method for collecting the adsorbent
after
use, and there is a problem that the adsorbent without such a study is
difficult to
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use in treatment for purifying wastewater.
The present inventors have also reported a technique for forming an organic
nanotube in which a low-molecular-weight organic compound is intercalated in a
glycolipid or a peptide lipid (see PTL 4). However, this technique is intended
for
introducing a dissolved low-molecular-weight organic compound such as a
fluorescent dye into a lipid in a bilayer membrane under a heated alcohol
environment, and is not a technique applicable to all kinds of treatment for
purifying wastewater.
The present inventors have also reported a technique for forming a
composite of an organic nanotube formed of a peptide lipid with gold nanop
articles
(see NPL 1). However, the surface of gold nanoparticles used for the composite
needs to be protected with an organic substance. Furthermore, an organic
nanotube and gold nanoparticles can form a composite only under a condition in
which organic functional groups present on the surfaces of the organic
nanotube
and the gold nanoparticles interact with each other, and there is no
description
about a composite that is formed under other conditions, e.g., by binding of
the
organic nanotube with the surface of the very metal.
As a technique relating to an organic nanomaterial, an organic nanotube
forming a composite with magnetite has been reported (see NPL 2). However,
oleic
acid is used for forming a composite with magnetite, leading to a problem of
generating wastewater containing oleic acid. Furthermore, because magnetite
and
the organic nanotube bind with each other based on electrostatic interaction
by the
surface potentials, magnetite and the organic nanotube are stable only under
acidic
levels but are released from the composite state under weakly acidic and
alkaline
levels. Hence, there is a problem that the composite cannot be used for all
kinds of
treatment for purifying wastewater.
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Citation List
Patent Literature
PTL 1: Japanese Patent Application Laid-Open (JP-A) No. 2004-275884
PTL 2: JP-A No. 05-245472
PTL 3: JP-A No. 2009-233825
PTL 4: JP-A No. 2008-264897
Non-Patent Literature
NPL 1: M. Kogiso, et al., Soft Matter, 2010, 6, 4528
NPL 2: Y.-G. Hang, et al., Colloids and Surfaces A, 2012, 395, 63
Summary of Invention
The present invention has an object to provide a nanocomposite that
overcomes the various problems in the related art, does not necessitate
pretreatment for, for example, oil content removal, salt removal, and
hydrogen sulfide removal, can simultaneously adsorb and easily and
efficiently remove oil contents, heavy metals, hydrogen sulfide, and organic
compounds only by being added to wastewater, can be easily collected after
adsorbing, and can be used for treatment for purifying wastewater of a wide
pH range of from acidic through weakly alkaline levels and a method for
producing the same, and an adsorbent containing the nanocomposite and a
method for using the same.
As a result of earnest studies for achieving the object described above, the
present inventors have found that an organic nanomaterial, which is a self-
assembled nanomaterial formed of a peptide lipid, simultaneously adsorbs
chemical
compounds such as oil contents, heavy metals, hydrogen sulfide, and organic
compounds included in wastewater. Furthermore, the present inventors have
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found that this organic nanomaterial forms a stable composite structure by
being mixed with magnetite nanoparticles, which are a ferromagnetic
material, in a water dispersion liquid adjusted to pH of from 3 through 4,
maintains adsorbability for the chemical compounds in a wide pH range of
from 1 through 9.5 once the organic nanomaterial forms the composite
structure, and can be easily collected by magnetism of, for example, a magnet
after adsorbing.
The present invention is based on the findings described above, and
some embodiments of the present invention are as follows.
<1> A nanocomposite, including:
an organic nanomaterial represented by general formula (1) below; and
magnetite nanoparticles,
wherein the nanocomposite is a composite formed of the organic
nanomaterial and the magnetite nanoparticles,
RCO - (NH -CHR' - CO), -OH ( 1 )
where in general formula (1), R represents a hydrocarbon group
containing from 6 through 24 carbon atoms, R' represents an amino acid side
chain, and m represents an integer of from 1 through 5.
<2> The nanocomposite according to <1>,
wherein the organic nanomaterial has a nanotube-shaped structure
having an outer diameter of from 10 nm through 200 nm.
<3> The nanocomposite according to <1> or <2>,
wherein RCO- represents any one of a myristoyl group, a palmitoyl
group, and a stearoyl group.
<4> The nanocomposite according to any one of <1> to <3>,
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wherein R' represents a hydrogen atom.
<5> The nanocomposite according to any one of <1> to <4>,
wherein m represents 1 or 2.
<6> An adsorbent, including:
the nanocomposite according to any one of <1> to <5> as an adsorbing
component.
<7> A method for using an adsorbent, the method including:
introducing the adsorbent according to <6> into treatment target water.
<8> The method for using an adsorbent according to <7>,
wherein the adsorbent is introduced into the treatment target water after
pH of the treatment target water is adjusted to from 1 through 9.5.
<9> The method for using an adsorbent according to <7> or <8>,
wherein the treatment target water is water produced incidentally with
production of an energy resource.
<10> A method for producing a nanocomposite, the method including:
a first water dispersion liquid preparing step of preparing a first water
dispersion liquid in which magnetite nanoparticles are dispersed and pH is
adjusted to 1 or lower;
a second water dispersion liquid preparing step of preparing a second
water dispersion liquid in which an organic nanomaterial represented by
general
formula (1) below is dispersed together with an alkali;
a mixed dispersion liquid preparing step of preparing a mixed dispersion
liquid in which the first water dispersion liquid and the second water
dispersion
liquid are mixed; and
a composite forming step of adjusting pH of the mixed dispersion liquid to
from 3 through 4 to allow the organic nanomaterial and the magnetite
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nanoparticles to undergo composite foimation,
RCO - (NH -CHR' -CO), -OH ( 1 )
where in general formula (1), R represents a hydrocarbon group
containing from 6 through 24 carbon atoms, R' represents an amino acid side
chain, and m represents an integer of from 1 through 5.
<11> The method for producing a nanocomposite according to <10>, further
including:
a separating step of magnetically attracting a nanocomposite in the
mixed dispersion liquid with a magnet to separate the nanocomposite from
the mixed dispersion liquid.
<12> The method for producing a nanocomposite according to <11>, further
including:
a re-dispersing step of re-dispersing in water, the nanocomposite
separated from the mixed dispersion liquid.
Advantageous Effects of Invention
In some embodiments, the present invention can provide a
nanocomposite that overcomes the various problems in the related art, does not
necessitate pretreatment for, for example, oil content removal, salt removal,
and
hydrogen sulfide removal, can simultaneously adsorb and easily and efficiently
remove oil contents, heavy metals, hydrogen sulfide, and organic compounds
only by being added to wastewater, can be easily collected after adsorbing,
and
can be used for treatment for purifying wastewater of a wide pH range of from
acidic through weakly alkaline levels and a method for producing the same, and
an adsorbent containing the nanocomposite and a method for using the same.
Brief Description of Drawings
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FIG. 1 is a diagram illustrating a scanning electron microscopic image of an
organic nanotube formed of N-(glycylglycine)pentadecane carboxamide.
FIG. 2A is a diagram illustrating a scanning transmission electron
microscopic image of a nanocomposite (adsorbing component) of Example 1.
FIG. 2B is a diagram exemplarily illustrating the structure of the
nanocomposite (adsorbing component) of Example 1.
FIG. 3 is a diagram illustrating a scanning transmission electron
microscopic image of a nanocomposite (adsorbing component) of Example 2.
Description of Embodiments
(Nanocomposite)
A nanocomposite of the present invention has a structure of a composite
formed of an organic nanomaterial represented by general formula (1) below and
magnetite nanoparticles.
RCO- (NH -CHIR' -00),-OH ( 1 )
In general formula (1) above, R represents a hydrocarbon group containing
from 6 through 24 carbon atoms, if represents an amino acid side chain, and m
represents an integer of from 1 through 5.
The hydrocarbon group represented by R in general formula (1) is not
particularly limited, may be straight-chained or branched-chained, but is
preferably
straight-chained. The hydrocarbon group is not particularly limited, may be
saturated or unsaturated, and preferably contains 3 or less double bonds when
the
hydrocarbon group is unsaturated.
The number of carbon atoms in the hydrocarbon group is not particularly
limited so long as the number of carbon atoms is from 6 through 24, but is
preferably from 10 through 19, more preferably from 11 through 17, and
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particularly preferably 11, 13, 15, or 17.
The kind of the hydrocarbon group is not particularly limited. Examples of
the kind of the hydrocarbon group include an alkyl group, a cycloalkyl group,
an
alkenyl group, a cycloalkenyl group, an alkynyl group, an aryl group, an
aralkyl
group, and a cycloalkylalkyl group. Among these kinds of hydrocarbon groups,
the
alkyl group and the alkenyl group are preferable. One, or 2 or more
appropriate
substituents may be substituted in these groups. Such substituents are not
particularly limited, and examples of such substituents include hydrocarbon
groups
containing 6 or less carbon atoms (e.g., an alkyl group, an alkenyl group, and
an
alkynyl group), halogens (e.g., a chlorine atom, a fluorine atom, an iodine
atom, and
a bromine atom), a hydroxyl group, an amino group, and a carboxyl group.
The most preferable hydrocarbon groups among these hydrocarbon groups
are a n-tridecyl group, a n-pentadecyl group, and a n-heptadecyl group with
which
RCO- in general formula (1) constitutes a myristoyl group, a palmitoyl group,
and a
stearoyl group.
The amino acid side chain represented by R' in general formula (1) is not
particularly limited, and the structure ((NH-CHR'-00)-) of the amino acid of
the
amino acid side chain may be the structure of the 20 kinds of natural amino
acids
(glycine, alanine, leucine, isoleucine, valine, arginine, lysine, glutamic
acid,
glutamine, aspartic acid, asparagine, cysteine, methionine, histidine,
proline,
phenylalanine, tyrosine, threonine, serine, and tryptophan), modified amino
acids,
and non-natural amino acids (e.g., ornithine, norvaline, norleucine,
hydroxylysine,
phenylglycine, and 6-alanine). Among these structures, glycine in which R' is
a
hydrogen atom is preferable.
m in general formula (1) represents a number of amino acid residues, is not
particularly limited so long as m is an integer of from 1 through 5, but is
preferably
1 or 2 and particularly preferably 2.
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The structure that is the most preferable as the structure ((NH-CHR'-00)-)
of the amino acid is the structure of glycylglycine in which R' is a hydrogen
atom
and m is 2.
The organic nanomaterial is a peptide lipid self-assembled from a compound
having the same constitution. The shape of the organic nanomaterial is not
particularly limited. For example, a nanotube shape, a nanofiber shape, a
spherical shape, and a thin plate shape are preferable. Among these shapes,
the
nanotube shape is particularly preferable.
The size of the organic nanomaterial is from 1 nm through some hundred of
nanometers on any of depth, width, and height.
Among these, a structure having the nanotube shape having an outer
diameter of from 10 nm through 200 nm is the most preferable.
The magnetite nanoparticles are not particularly limited and may be
appropriately selected for use from particles produced by known methods.
Examples of known methods include the method described in United States Patent
No. 3843540. The particle diameter of the magnetite nanoparticles is smaller
than
the diameter of the organic nanomaterial, and is preferably from 1 nm through
100
nm.
The nanocomposite can be produced by a producing method described below.
(Adsorbent)
An adsorbent of the present invention contains an adsorbing component,
and contains other components as needed.
<Adsorbing component>
The adsorbing component is the nanocomposite of the present invention.
The details of the adsorbing component are the same as described above about
the
nanocomposite. Hence, a redundant description will not be given.
<Other components>
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The other components are not particularly limited so long as such other
components do not hinder the effect of the present invention. Examples of the
other components include arbitrary components such as a dispersion liquid for
when the adsorbent is subjected to, for example, preservation and storage in
the
form of a dispersion liquid in which the adsorbing component is dispersed.
(Method for using adsorbent)
A method for using an adsorbent of the present invention is a method of
introducing the adsorbent of the present invention into treatment target
water.
In the adsorbing component contained in the adsorbent, a stable composite
structure is maintained once the organic nanomaterial and the magnetite
nanoparticles form a composite, and the magnetite nanoparticles do not
separate
from the organic nanomaterial in a wide pH range of from acidic through weakly
alkaline levels. This enables treatment for purifying the treatment target
water to
be performed in a wide pH range of from 1 through 9.5.
Even when pH of the treatment target water is outside the range of
application, addition of an appropriate acid or alkali for adjusting pH to be
within
the range of application enables application of the adsorbent.
That is, when pH of the treatment target water measures from 1 through
9.5, the adsorbent is introduced into the treatment target water without
adjustment
of pH. When pH of the treatment target water does not measure from 1 through
9.5, the adsorbent can be introduced into the treatment target water after pH
is
adjusted to from 1 through 9.5.
The treatment target water is not particularly limited. Examples of the
treatment target water include produced water produced incidentally with
production of energy resources such as petroleum, shale oil, coal bed methane
gas,
methane gas, shale gas, and oil sand, mineral wastewater accompanying mineral
production, water (flowback water) that returns to the ground together with a
gas
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after shale is hydraulically fractured with a large amount of water, and all
kinds of
wastewater including various kinds of industrial wastewater.
(Method for producing nanocomposite)
A method for producing a nanocomposite of the present invention is a
method for producing the nanocomposite of the present invention, and includes
at
least a first water dispersion liquid preparing step, a second water
dispersion liquid
preparing step, a mixed dispersion liquid preparing step, and a composite
forming
step, and includes other steps as needed.
<First water dispersion liquid preparing step>
The first water dispersion liquid preparing step is a step of preparing a
first
water dispersion liquid in which magnetite nanoparticles are dispersed and pH
is
adjusted to 1 or lower.
As the magnetite particles, the magnetite particles described with regard to
the nanocomposite of the present invention can be used.
Examples of a method for adjusting the water dispersion liquid of the
magnetite particles to a strong acidic pH level of 1 or lower include a method
of
adding a strong acid such as hydrochloric acid and nitric acid. At such pH,
the
magnetite particles in an aggregating state can be dispersed in water.
<Second water dispersion liquid preparing step>
The second water dispersion liquid preparing step is a step of preparing a
second water dispersion liquid in which the organic nanomaterial is dispersed
together with an alkali. Addition of the alkali enables the organic
nanomaterial to
be dispersed in water in a state that a carboxylic acid present at an end of
the
organic nanomaterial is ionized.
The organic nanomaterial is not particularly limited. An organic
nanomaterial synthesized by a known synthesizing method may be appropriately
selected for use. Examples of the known synthesizing method include a
producing
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method described in Soft Matter, 2010, 6th volume, p. 4,528.
The alkali is not particularly limited. In terms of being used for
purification of wastewater, the alkali is preferably an inorganic salt and
particularly preferably sodium hydroxide.
The amount of the alkali to be added is not particularly limited but is
preferably from 0.1 molar equivalent through 1.0 molar equivalent of the
organic
nanomaterial.
<Mixed dispersion liquid preparing step>
The mixed dispersion liquid preparing step is a step of preparing a mixed
dispersion liquid in which the first water dispersion liquid and the second
water
dispersion liquid are mixed.
The method for mixing is not particularly limited. Mixing may be
performed by a known method.
<Composite forming step>
The composite forming step is a step of adjusting pH of the mixed dispersion
liquid to from 3 through 4 to allow the organic nanomaterial and the magnetite
nanoparticles to undergo composite formation.
Outside this pH range, dispersibility of the organic nanomaterial and the
magnetite nanoparticles is low. Therefore, it is difficult for the organic
nanomaterial and the magnetite nanoparticles to undergo composite formation,
and
the composite state is gradually resolved at weakly acidic and weakly alkaline
levels before the composite state becomes stable.
On the other hand, when the mixed dispersion liquid is adjusted to be
within this pH range, it is possible for the organic nanomaterial and the
magnetite
nanoparticles to undergo composite formation in a suitably dispersed state
respectively. Once a composite is formed, a stable composite structure is
maintained and the magnetite nanoparticles will not separate from the organic
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nanomaterial in a wide pH range of from acidic through weakly alkaline levels.
This is an unknown feature as can be seen from the fact that the compound
described in NPL 2 will have magnetite particles separate due to a surface
potential
change that occurs when the dispersion liquid is returned from an acidic level
to a
neutral level. When the nanocomposite is applied to an adsorbent, the
nanocomposite can be used in treatment for purifying wastewater of a wide pH
range. Therefore, the nanocomposite imparts excellent versatility to the
adsorbent.
Examples of the method for adjusting pH of the mixed dispersion liquid to
from 3 through 4 include a method of adding an appropriate acid or alkali.
<Other steps>
The other steps are not particularly limited and may be any steps so long as
such steps do not hinder the effect of the present invention. Examples of the
other
steps include a separating step and a re-dispersing step.
-Separating step-
The separating step is a step of magnetically attracting the nanocomposite
in the mixed dispersion liquid with a magnet to separate the nanocomposite
from
the mixed dispersion liquid.
Examples of the method for collecting the nanocomposite from the
dispersion liquid include a filtration method using a filter. The
nanocomposite
contains the magnetite nanoparticles as a ferromagnetic. Therefore, the
nanocomposite can be easily collected from the dispersion liquid with a
magnet.
-Re-dispersing step-
The re-dispersing step is a step of re-dispersing in water, the nanocomposite
separated from the mixed dispersion liquid.
By performing the separating step and the re-dispersing step, it is possible
to produce the nanocomposite that is free of the magnetite particles and
suppressed
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in inclusion of impurities.
Examples of the present invention will be described in detail below. The
spirit of the present invention is not limited by these Examples.
Examples
(Example 1)
[Synthesis of N-(glycylglycine)pentadecane carboxamide (organic nanomaterial
precursor)]
An aqueous solution (77.1 mL) of sodium hydroxide (36.5 millimoles) was
added to glycylglycine (4.82 g) (36.5 millimoles). To the resultant, an
aqueous
solution (40 mL) of sodium hydroxide (36.5 millimoles) and an acetone solution
(30
mL) of a pentadecane carboxylic acid chloride (36.5 millimoles) were dropped
simultaneously. One day later, the reaction solution was added to hydrochloric
acid (70 mL) (73 millimoles), and a precipitate was filtrated and then washed
with
water (150 mL) until the filtrate became neutral. The crude product was
suspended in methanol (60 mL) and refluxed for some hours. Then, a precipitate
was filtrated and washed with methanol, to obtain 9.5 g of N-
(glycylglycine)pentadecane carboxamide, which was an organic nanomaterial
precursor (at a yield of 75%).
[Synthesis of organic nanomaterial]
Five grams of the obtained N-(glycylglycine)pentadecane carboxamide was
dispersed in methanol (1 L) and dissolved while being refluxed at 60 degrees
C.
This methanol solution was subjected to a rotary evaporator, and while being
heated at 60 degrees C, was evaporated to dryness, to obtain an organic
nanomaterial formed by self-assembling of N-(glycylglycine)pentadecane
carboxamide.
As illustrated in FIG. 1, this organic nanomaterial had a nanotube structure
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having an average outer diameter of 80 nm. FIG. 1 is a diagram illustrating a
scanning electron microscopic image of the organic nanotube formed of N-
(glycylglycine)pentadecane carboxamide.
[Production of nanocomposite and adsorbent]
A first water dispersion liquid (0.5 mL) was prepared by dispersing
magnetite nanoparticles having an average diameter of 25 nm (10 mg) in water
and
adjusting pH to 1 with 1 M hydrochloric acid (first water dispersion liquid
preparing step).
A second water dispersion liquid was prepared by dispersing the organic
nanomaterial (34 mg) in a mixed liquid of a 1 M sodium hydroxide aqueous
solution
(0.1 mL) and water (1 mL) (second water dispersion liquid preparing step).
Subsequently, the first water dispersion liquid and the second water
dispersion liquid were mixed to prepare a mixed dispersion liquid of these
liquids
(mixed dispersion liquid preparing step).
Subsequently, the mixed dispersion liquid was adjusted to pH of 3.5 by
addition of a 1 M hydrochloric acid, to allow the organic nanomaterial and the
magnetite nanoparticles to undergo composite formation (composite forming
step).
Subsequently, the nanocomposite included in the mixed dispersion liquid
and having a solid state was magnetically attracted with a magnet and
separated
from the mixed dispersion liquid (separating step).
Subsequently, the separated nanocomposite was re-dispersed in water (re-
dispersing step).
The separating step and the re-dispersing step were repeated twice in total,
to produce an adsorbent, which was a nanocomposite of Example 1 and contained
the nanocomposite as an adsorbing component, in the form of a dispersion
liquid (2
mL) of the adsorbing component.
When the nanocomposite (adsorbing component) having a solid state was
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separated from the dispersion liquid, it was confirmed that composite
formation was
by the magnetite nanoparticles being bound with the organic nanomaterial, as
illustrated in FIGS. 2A and 2B. FIG. 2A is a diagram illustrating a scanning
transmission electron microscopic image of the nanocomposite (adsorbing
component) of Example 1. FIG. 2B is an exemplary diagram exemplarily
illustrating the structure of the nanocomposite (adsorbing component) of
Example
1. The reference numeral 1 denotes the organic nanomaterial and the reference
numeral 2 denotes the magnetite nanoparticles.
(Reference Example 1)
The above organic nanomaterial (34 mg) was dispersed in a mixed liquid of a
1 M sodium hydroxide aqueous solution (0.1 mL) and water (2 mL), to produce a
dispersion liquid (2.1 mL) of the organic nanomaterial as an adsorbent of
Reference
Example 1.
(Metal ion adsorbing test)
A 10 mM copper chloride aqueous solution (0.5 mL) and a 10 mM
magnesium chloride aqueous solution (0.5 mL) were added to the adsorbent
(dispersion liquid of the organic nanomaterial) of Reference Example 1.
Subsequently, a 1 M sodium hydroxide aqueous solution was added to the
resultant to adjust pH to 7. A produced precipitate was removed through a 0.45
pm filter and an optical spectrum of the filtrate was measured.
A 10 mM copper chloride aqueous solution (0.5 mL) and a 10 mM calcium
chloride aqueous solution (0.5 mL) were added to the nanocomposite or the
adsorbent (dispersion liquid of the adsorbing component) of Example 1.
Finally,
water was added to make the total 5 mL.
Subsequently, a 1 M sodium hydroxide aqueous solution was added to the
resultant to adjust pH to 7.5. A produced precipitate was removed through a
0.45
pm filter and an optical spectrum of the filtrate was measured.
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The results of the optical spectrum measurement of the adsorbent of
Reference Example 1 and the nanocomposite or the adsorbent of Example 1 are
presented in Table 1 below. The result of optical spectrum measurement of a 1
mM
copper chloride aqueous solution is also presented in Table 1 below as a
sample for
reference. Each result of measurement is expressed as absorbance at 750 nm in
a
peak wavelength region.
Table 1
Measurement target Absorbance (750 nm)
1 mM copper chloride aqueous solution 0.048
Reference Example 1 0.004
Example 1 0.001
As presented in Table 1 above, from comparison with the absorbance of the 1
mM copper chloride aqueous solution (sample for reference), it was confirmed
that
the adsorbent of Reference Example 1 was able to adsorb and remove copper
ions,
which were a heavy metal.
The nanocomposite or the adsorbent of Example 1 resulted in a significantly
low absorbance like the adsorbent of Reference Example 1. Hence, it was
confirmed that an equal level of adsorption/removal was possible even after
the
composite formation with magnetite nanoparticles.
(Example 2)
A nanocomposite or an adsorbent of Example 2 was produced in the same
manner as in the production of the nanocomposite or the adsorbent of Example
1,
except that unlike in the production of the nanocomposite or the adsorbent of
Example 1, the second water dispersion liquid preparing step was performed in
the
manner described below. That is, the second water dispersion liquid preparing
step was performed by dispersing the organic nanomaterial (25 mg) in a mixed
liquid of a 30 wt% sodium deuteroxide aqueous solution (0.01 mL) and heavy
water
(2 mL), to prepare a second water dispersion liquid.
When the nanocomposite (adsorbing component) having a solid state was
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separated from the dispersion liquid, it was confirmed that composite
formation was
by the magnetite nanoparticles being bound with the organic nanomaterial, as
illustrated in FIG. 3. FIG. 3 is a diagram illustrating a scanning
transmission
electron microscopic image of the nanocomposite (adsorbing component) of
Example
2. The average outer diameter of this organic nanomaterial was 80 nm.
(Reference Example 2)
The above organic nanomaterial (25 mg) was dispersed in a mixed liquid of a
30 wt% sodium deuteroxide aqueous solution (0.01 mL) and heavy water (4.59
mL),
to produce a dispersion liquid (5 mL) of the organic nanomaterial as an
adsorbent of
Reference Example 2.
(Organic compound adsorbing test)
[Preparation of sample for reference]
Phenol (0.5 mg) and propionic acid (1 mg), which were organic compounds,
and dimethylsulfone (10 mg), which was an internal standard for NMR, were
dissolved in heavy water respectively and shaken at room temperature for 1
hour, to
prepare a sample for reference for 111-NMR (5 mL).
Like the sample for reference, phenol (0.5 mg), propionic acid (1 mg), and
dimethylsulfone (10 mg) were added to the adsorbent (dispersion liquid of the
organic nanomaterial) of Reference Example 2. The resultant was finally
prepared
in a total amount of 5 mL with heavy water. The resultant was shaken at room
temperature for 1 hour, a solid component was removed through a 0.45 pm
filter,
and the concentration of the residual component was measured by 11--I-NMR.
Like the sample for reference, phenol (0.5 mg), propionic acid (1 mg), and
dimethylsulfone (10 mg) were added to the nanocomposite or the adsorbent
(dispersion liquid of the adsorbing component) of Example 2. The resultant was
finally prepared in a total amount of 5 mL with heavy water. The resultant was
shaken at room temperature for 1 hour, a solid component was removed through a
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0.45 pin filter, and the concentration of the residual component was measured
by
'1-I-NMR.
The results of measurement of the adsorbents of Reference Example 2 and
Example 2 by 11-I-NMR are presented in Table 2 below. The result of
measurement
of the sample for reference is also presented in Table 2 below.
Table 2
Measurement target Phenol (ppm) Propionic acid (ppm)
Sample for reference 96 216
Reference Example 2 78 186
Example 2 80 189
As presented in Table 2 above, it was confirmed that the adsorbent of
Reference Example 2 was able to adsorb and remove 18 ppm of phenol and 30 ppm
of propionic acid per 5,000 ppm of the organic nanomaterial.
It was also confirmed that the nanocomposite or the adsorbent of Example 2
was able to adsorb and remove 16 ppm of phenol and 27 ppm of propionic acid
per
5,000 ppm of the adsorbing component, and that an equal level of
adsorption/removal was possible even after the composite formation with
magnetite
nanoparticles.
Industrial Applicability
According to the nanocomposite, the method for producing the same, the
adsorbent containing the nanocomposite, and the method for using the same of
the
present invention, it is possible to remove chemical components included in
wastewater, and to easily collect the chemical components with a magnet owing
to
composite formation with a ferromagnetic. Therefore, the nanocomposite, the
method for producing the same, the adsorbent containing the nanocomposite, and
the method for using the same are very useful in the field of wastewater
purification in, for example, petroleum gas development and chemical plants.
Besides, an embodiment in the form of an organic nanomaterial forming a
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composite with a ferromagnetic can also be used in, for example, the field of
electronic part materials and the field of a contrast agent for testing an
adsorbed
chemical component.
Reference Signs List
1: organic nanomaterial (organic nanotube)
2: magnetite nanoparticles
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