CA2968493C - Nanocomposite and method for producing same, and adsorbent and method for using same - Google Patents
Nanocomposite and method for producing same, and adsorbent and method for using same Download PDFInfo
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- C07C233/47—Carboxylic acid amides having carbon atoms of carboxamide groups bound to hydrogen atoms or to acyclic carbon atoms having the nitrogen atom of at least one of the carboxamide groups bound to a carbon atom of a hydrocarbon radical substituted by carboxyl groups with the substituted hydrocarbon radical bound to the nitrogen atom of the carboxamide group by an acyclic carbon atom having the carbon atom of the carboxamide group bound to a hydrogen atom or to a carbon atom of an acyclic saturated carbon skeleton
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Abstract
[Problem] To provide: a nanocomposite capable of easily and efficiently removing and simultaneously absorbing an oily component, a heavy metal, hydrogen sulfide, and an organic compound merely by adding wastewater, without requiring a pretreatment such as oil removal, desalinization, or hydrodesulfurization, capable of easily recovering the same after absorption, and further capable of being used in the purification of wastewater in a broad pH range from acidic to slightly alkaline; a method for producing the same; an absorbent containing the nanocomposite; and a method for using the same. [Solution] A nanocomposite according to the present invention is characterized in that magnetite nanoparticles are conjugated with an organic nano-material represented by general formula (1). In general formula (1), R represents a C6-24 hydrocarbon group, R' represents an amino acid sidechain, and m represents an integer of 1-5.
Description
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 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
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 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
2 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.
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.
3 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
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
4 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>,
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>,
5 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
<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
6 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
<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
7 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
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
8 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.
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.
9 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 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>
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 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 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 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 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 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 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.
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 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 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 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
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 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>
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 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 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 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 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 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 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.
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 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 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 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
Claims (12)
1. A nanocomposite, comprising:
an organic nanomaterial represented by general formula (1) below; and magnetite nanoparticles, wherein the nanocomposite is a composite formed by the magnetite nanoparticles being directly bound with a hydrophilic site of the organic nanomaterial, RCO - (NH -CHR' - CO), -OH ( 1 ) where in general formula (1), R represents a hydrocarbon group that comprises from 6 through 24 carbon atoms, R' represents an amino acid side chain, and m represents an integer of from 1 through 5.
an organic nanomaterial represented by general formula (1) below; and magnetite nanoparticles, wherein the nanocomposite is a composite formed by the magnetite nanoparticles being directly bound with a hydrophilic site of the organic nanomaterial, RCO - (NH -CHR' - CO), -OH ( 1 ) where in general formula (1), R represents a hydrocarbon group that comprises 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 claim 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 claim 1 or 2, wherein RCO- represents a myristoyl group, a palmitoyl group, or a stearoyl group.
4. The nanocomposite according to any one of claims 1 to 3, wherein R' represents a hydrogen atom.
5. The nanocomposite according to any one of claims 1 to 4, =
wherein m represents 1 or 2.
wherein m represents 1 or 2.
6. An adsorbent, comprising:
the nanocomposite as defined in any one of claims 1 to 5 as an adsorbing component.
the nanocomposite as defined in any one of claims 1 to 5 as an adsorbing component.
7. A method for using an adsorbent, the method comprising:
introducing the adsorbent as defined in claim 6 into treatment target water.
introducing the adsorbent as defined in claim 6 into treatment target water.
8. The method for using an adsorbent according to claim 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 claim 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 comprising:
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 nanoparticles to undergo composite formation, RCO- (NH-CHR' -CO),--OH ( i ) where in general formula (1), R represents a hydrocarbon group that comprises from 6 through 24 carbon atoms, R' represents an amino acid side chain, and m represents an integer of from 1 through 5.
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 nanoparticles to undergo composite formation, RCO- (NH-CHR' -CO),--OH ( i ) where in general formula (1), R represents a hydrocarbon group that comprises 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 claim 10, further comprising:
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.
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 claim 11, further comprising:
a re-dispersing step of re-dispersing in water, the nanocomposite separated from the mixed dispersion liquid.
a re-dispersing step of re-dispersing in water, the nanocomposite separated from the mixed dispersion liquid.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2014237158 | 2014-11-21 | ||
| JP2014-237158 | 2014-11-21 | ||
| PCT/JP2015/082799 WO2016080545A1 (en) | 2014-11-21 | 2015-11-20 | Nanocomposite and method for producing same, and absorbent and method for using same |
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| CA2968493A1 CA2968493A1 (en) | 2016-05-26 |
| CA2968493C true CA2968493C (en) | 2022-05-17 |
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| JP (1) | JP6528100B2 (en) |
| CA (1) | CA2968493C (en) |
| MX (1) | MX2017006508A (en) |
| WO (1) | WO2016080545A1 (en) |
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| US7834139B2 (en) * | 2004-03-19 | 2010-11-16 | Research Foundation Of The City University Of New York | Magnetic nanotubes |
| JP5610460B2 (en) * | 2009-08-07 | 2014-10-22 | 独立行政法人産業技術総合研究所 | Nanoparticle dispersible in water and method for producing nanoparticle dispersion |
| JP2012040631A (en) * | 2010-08-18 | 2012-03-01 | National Institute Of Advanced Industrial Science & Technology | Peapod organic nanotube encapsulating metal or metal oxide nanoparticle |
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| MX2017006508A (en) | 2018-03-23 |
| CA2968493A1 (en) | 2016-05-26 |
| JP6528100B2 (en) | 2019-06-12 |
| JPWO2016080545A1 (en) | 2017-11-02 |
| WO2016080545A1 (en) | 2016-05-26 |
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