JP2015066510A - Aromatic amine adsorbent, quartz resonator gas sensor using the same and manufacturing method of these - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adsorbent exhibiting high sensitivity only to an aromatic amine, a production method thereof, and an application thereof.
The aromatic amine adsorbent of the present invention comprises a synthetic resin containing a carbon porous body having a functional group. Preferably, the functional group is at least one selected from the group consisting of a hydroxy group, a carbonyl group, a carboxyl group, and an ether group. Preferably, the synthetic resin is in a fiber shape, and a carbon porous body having a functional group is contained in the fiber-shaped synthetic resin.
[Selection] FIG.

Description

  The present invention relates to an aromatic amine adsorbent exhibiting a high adsorbing power only with respect to an aromatic amine, a quartz resonator gas sensor using the same, and a method for producing them.

  Lung cancer is one cancer that can be ameliorated by appropriate treatment if detected at an early stage. However, many detection methods for lung cancer are expensive and time-consuming, and many people lose their lives due to lung cancer without early detection. Therefore, the development of an easy and inexpensive screening test is expected especially for patients with a potentially high lung cancer risk, such as smokers and workers in specific industries.

  Cigarette smoke, yakiniku, vegetables, or aromatic amines in industrial waste are structurally related to carcinogens. Daily exposure to aromatic amines increases the probability of ingestion into the body and, as a result, may increase the risk of suffering from occupational cancer. Aromatic amines such as aniline and toluidine can be detected not only in smoker excrement (eg, exhaled breath and urine) but also in non-smokers with lung cancer. That is, aromatic amines can be one of the exogenous causative agents of lung cancer. Therefore, if aromatic amines can be detected by breath gas analysis, it is advantageous for finding potential lung cancer patients. Aromatic amines can be detected accurately and quantitatively by gas chromatography and other sensing techniques, but there is no easy and high-throughput method capable of detecting very small amounts of aromatic amines.

  On the other hand, porous materials are used in sensing technology due to their large adsorption capacity and high substance selectivity. However, there is no known porous material that exhibits high selectivity only for aromatic amines.

  As described above, an object of the present invention is to provide an adsorbent exhibiting high sensitivity only to an aromatic amine, a production method thereof, and an application thereof.

The aromatic amine adsorbent according to the present invention comprises a synthetic resin containing a carbon porous body having a functional group, thereby solving the above-mentioned problems.
The functional group may be selected from the group consisting of a hydroxy group, a carbonyl group, a carboxyl group, and an ether group.
The synthetic resin is in a fiber shape, and the carbon porous body having the functional group may be contained in the fiber-shaped synthetic resin.
The diameter of the fiber may be in the range of 50 nm to 1 μm.
The synthetic resin is in the form of a film, and the carbon porous body having the functional group may be contained in the film-shaped synthetic resin.
The mass ratio between the synthetic resin and the carbon porous body having the functional group may be in the range of 1: 0.2 to 1: 5.
The carbon porous body is a cage-type carbon porous body, the specific surface area of the cage-type carbon porous body is 1300 m ² / g or more, and the specific pore volume is 1.5 cm ³ / g or more. Also good.
The carbon porous body may be a cage-type carbon porous body, and a cage diameter of the cage-type carbon porous body may be 5 nm or more and 15 nm or less.
The porous carbon body may be a cage-type carbon porous body, and the cage-type carbon porous body may be manufactured using a porous silica body having a face-centered cubic lattice structure and a space group Fm3m as a template.
The synthetic resin is at least one selected from the group consisting of polymethyl methacrylate (PMMA), polymethyl acrylate (PAA), polydimethylsiloxane (PDMS), polyvinyl acetate, epoxy resin, polystyrene, polycarbonate, polypropylene, polybutadiene, and polyethylene. One may be selected.
Aniline may be adsorbed as an aromatic amine.
The method for producing an aromatic amine adsorbent according to the present invention includes a step of providing a polymer solution containing a carbon porous body having a functional group and a synthetic resin, thereby solving the above-mentioned problems.
In the applying step, a voltage may be applied to a syringe containing the polymer solution by electrospinning, and the polymer solution may be ejected from the syringe and collected by a collector.
The distance between the syringe and the collector may be 2 cm or more and 10 cm or less.
The content of the synthetic resin and the content of the carbon porous body having the functional group in the polymer solution may be more than 5% by mass and 15% by mass or less, respectively.
The solvent of the polymer solution may be selected from the group consisting of N, N-dimethylformamide (DMF), tetrahydrofuran (THF), dichloromethane, chloroform, dioxane, acetone, ethyl acetate, toluene, and benzene. .
The solvent of the polymer solution may be a combination of N, N-dimethylformamide (DMF) and tetrahydrofuran (THF).
In the applying step, the polymer solution may be dropped by a casting method.
In the quartz resonator gas sensor according to the present invention, the above-described aromatic amine adsorbent is applied to the quartz resonator electrode, thereby solving the above-described problems.
The method for manufacturing a quartz resonator gas sensor according to the present invention includes a step of applying a polymer solution containing a carbon porous body having a functional group and a synthetic resin to a quartz resonator electrode, thereby solving the above-described problems.

  The aromatic amine adsorbent according to the present invention comprises a synthetic resin containing a carbon porous body having a functional group. Since only the aromatic amine can be adsorbed to the carbon porous body by the functional group, it can function as an adsorbent. If such an adsorbent is supported on a quartz resonator, a gas sensor for detecting a minute amount of aromatic amine can be obtained.

Schematic diagram of aromatic amine adsorbent according to the present invention Schematic diagram of a carbon porous body having a functional group The figure which shows a mode that the film-like aromatic amine adsorbent by this invention is manufactured. The figure which shows a mode that the fiber-shaped aromatic amine adsorbent by this invention is manufactured. Schematic diagram of a quartz crystal gas sensor according to the present invention The figure which shows the SEM image of the sample of Example 1 and Comparative Example 3 The figure which shows the crystal oscillator gas sensor device The figure which shows the response constant with respect to the aniline of the sample of Example 1 and Comparative Examples 2-3. Diagram showing IR spectrum of CNC and AC The figure which shows the Raman spectrum of CNC and AC The figure which shows XPS spectrum (A) of CNC and XPS spectrum (B) of AC Diagram showing model of CNC and aniline using density functional molecular dynamics method (DFMD) The figure which shows the SEM image of the sample of the reference example 4 The figure which shows another SEM image of the sample of the reference example 4 The figure which shows the SEM image of the sample of the reference example 5 The figure which shows the SEM image of the sample of Example 6. The figure which shows the response constant with respect to the aniline of the sample of Example 6. The figure which shows the repetition tolerance with respect to the aniline of the sample of Example 6. The figure which shows the response constant with respect to the various volatile organic compound of the sample of Example 6. The figure which shows the adsorption isotherm (a) with respect to the aniline and benzene of the sample of Example 6, and its Langmuir plot (b). The figure which shows another repetition tolerance with respect to the aniline of the sample of Example 6

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same reference number is attached | subjected to the same component and the description is abbreviate | omitted.

(Embodiment 1)
In Embodiment 1, the aromatic amine adsorbent according to the present invention and the production method thereof will be described in detail.

FIG. 1 shows a schematic diagram of an aromatic amine adsorbent according to the present invention.
FIG. 2 shows a schematic diagram of a carbon porous body having a functional group.

  The aromatic amine adsorbents 110 and 120 according to the present invention are made of a synthetic resin 140 containing a carbon porous body 130 having a functional group. Since only the aromatic amine can be adsorbed to the carbon porous body by the functional group, it can function as an adsorbent. Among the aromatic amines, the aromatic amine adsorbent of the present invention can contribute to detection of carcinogenic substances and early detection of latent lung cancer patients because it is effective for adsorption of aniline among aromatic amines.

  FIG. 1A shows a film-shaped aromatic amine adsorbent 110 in which a synthetic resin 140 is in a film form and contains a carbon porous body 130 having a functional group in a state dispersed in the film-shaped synthetic resin 140. Indicates. Such an aromatic amine adsorbent 110 is preferable because it is easy to manufacture.

  FIG. 1B shows a fiber-shaped aromatic amine adsorbent 120 in which the synthetic resin 140 is in the form of a fiber and contains the carbon porous body 130 having functional groups in a state dispersed in the fiber-shaped synthetic resin 140. Indicates. Such an aromatic amine adsorbent 120 is preferable because it has higher sensitivity to aromatic amines than the film-like aromatic amine adsorbent 110.

  The fiber diameter (fiber diameter) d of the fiber-shaped synthetic resin 140 is in the range of 50 nm to 1 μm. Within this range, diffusion of the analyte gas containing an aromatic amine such as aniline into the fiber is promoted, thus enabling sensitive sensing.

  As schematically shown in FIG. 2, the carbon porous body 130 having a functional group has a functional group 220 in the carbon porous body 210. In FIG. 2, the carbon porous body 210 is illustratively a cage-type carbon porous body. The cage-type carbon porous body has a face-centered cubic lattice structure and is manufactured using a silica porous body (also referred to as KIT-5) having a space group Fm3m as a template.

If the carbon porous body 210 is a cage-type carbon porous body and has a specific surface area of 1300 cm ² / g or more and a specific pore capacity of 2.5 cm ³ / g or more, the specific surface area is large and the sensitivity to aromatic amines is large. Is preferable. The larger the specific surface area and specific pore volume, the greater the sensitivity to aromatic amines, so there is no particular upper limit. However, due to synthesis limitations, the specific surface area is 2500 cm ² / g or less, and the specific pore volume is 4 It is considered to be 0.0 cm ³ / g or less.

  The functional group 220 is at least one selected from the group consisting of a hydroxy group, a carbonyl group, a carboxyl group, and an ether group. Since these functional groups form a hydrogen bond with the amine group of the aromatic amine, the aromatic amine can be adsorbed to the carbon porous body 210 with certainty.

  For example, Japanese Patent No. 4724877, A. Vinu et al. Mater. Chem. , 2005, 15, 5122-5127, etc., the hydroxyl group contained in saccharides typified by sucrose and glucose used as a starting material is mentioned above in the production process. Thus, the carbon porous body 130 having a functional group can be obtained.

  In FIG. 2, a cage-type carbon porous body is illustrated as the carbon porous body 130 having a functional group, but is not limited thereto. If it has the above-mentioned functional group, arbitrary carbon porous bodies can be adopted. Examples of such a carbon porous body include a carbon porous body obtained by using a silica porous body called MCM-48, SBA-15, or SBA-1 other than KIT-5 described above as a template. Since these also use saccharides as a starting material, a carbon porous body having a functional group can be obtained.

  Returning again to FIG. The synthetic resin 140 is at least one selected from the group consisting of polymethyl methacrylate (PMMA), polymethyl acrylate (PAA), polydimethylsiloxane (PDMS), polyvinyl acetate, epoxy resin, polystyrene, polycarbonate, polypropylene, polybutadiene, and polyethylene. Is selected. These may be used alone or in combination. These synthetic resins can be easily formed into a film shape or a fiber shape, and the carbon porous body 130 can be dispersed and contained in the synthetic resin.

  Furthermore, the mass ratio between the synthetic resin 140 and the carbon porous body 130 having a functional group is preferably 1: 0.2 or more and 1: 5 or less. When the mass ratio of the synthetic resin 140 and the carbon porous body 130 having a functional group is less than 1: 0.2, the amount of the carbon porous body 130 having a functional group is too small. is there. When the mass ratio of the synthetic resin 140 and the carbon porous body 130 having a functional group exceeds 1: 5, the carbon porous body 130 having a functional group may not be dispersed in the synthetic resin 140 and may aggregate. More preferably, the mass ratio of the synthetic resin 140 and the carbon porous body 130 having a functional group is 1: 0.5 or more and 1: 1 or less. If it is this range, the carbon porous body 130 which has a functional group can be disperse | distributed and contained even if the synthetic resin 140 is a film | membrane form or a fiber form. In particular, when the fiber-shaped synthetic resin 140 contains the carbon porous body 130 having a functional group, a uniform fiber can be obtained. 0.7 or more and 1: 1 or less are preferable.

  Next, the manufacturing method of the aromatic amine adsorbent of the present invention will be described in detail.

  The method for producing an aromatic amine adsorbent of the present invention includes a step of providing a polymer solution containing a carbon porous body having a functional group and a synthetic resin. The polymer solution is prepared by mixing the above-described carbon porous body having a functional group and a synthetic resin and dissolving the mixture in a solvent. Since the carbon porous body and synthetic resin which have these functional groups are as having demonstrated with reference to FIG. 1 and FIG. 2, they are abbreviate | omitted.

  The solvent of the polymer solution is at least one selected from the group consisting of N, N-dimethylformamide (DMF), tetrahydrofuran (THF), dichloromethane, chloroform, dioxane, acetone, ethyl acetate, toluene, and benzene. If these solvents are used, the above-described synthetic resin can be dissolved, so that the application is facilitated.

  FIG. 3 is a view showing a state of producing a membranous aromatic amine adsorbent according to the present invention.

  In FIG. 3, the applying step may be performed by dropping the polymer solution 310 onto a desired base material such as a substrate or a crystal resonator electrode by a so-called casting method. The concentration of the polymer solution 310 and the amount to be dropped can be appropriately adjusted depending on the size and thickness of the membrane-like aromatic amine adsorbent to be produced. The concentration of the exemplary polymer solution 310 is such that the content of the carbon porous body having a functional group and the synthetic resin in the polymer solution 310 are 0.05% by mass to 1.5% by mass and 0.1% by mass, respectively. % To 0.3% by mass. Exemplary dripped amounts range from 0.5 μL to 1 μL. Thereby, the aromatic amine obtained spreads on the base material after dropping and forms a film, and the carbon porous body having a functional group can be dispersed in the synthetic resin.

  Moreover, it is preferable to heat the base material prior to the applying step. Thereby, since the surface wettability of the base material is reduced, the dropped polymer solution 310 can remain on the base material surface. For heating the base material, a heating means such as an oven, a hot plate, or a thermostatic bath may be used. The heating temperature and time are, for example, 40 ° C. or more and 100 ° C. or less and 15 minutes to 1 hour.

  Following the applying step, the dropped polymer solution may be dried. Thereby, the solvent in the polymer solution 310 is surely removed, so that the synthetic resin can be fixed in a film shape. For the drying, for example, a heating means such as an oven, a hot plate, or a thermostatic bath may be used. The heating temperature and time are illustratively between 40 ° C. and 100 ° C. for 30 minutes to 2 hours, although depending on the type of solvent selected, film thickness, and the like.

  FIG. 4 is a diagram showing a state of producing a fiber-like aromatic amine adsorbent according to the present invention.

  In FIG. 4, in the applying step, a voltage is applied to the syringe containing the polymer solution 310 by the electrospinning method, and the polymer solution 310 is ejected from the syringe and collected by the collector 410.

  The syringe has a spinneret (φ = 0.05 mm to 0.2 mm) through which the polymer solution 310 is ejected. A high voltage power source is connected to the syringe. The collector 410 is a desired base material such as a substrate or a crystal resonator electrode. The collector 410 is grounded.

  Specifically, the polymer solution 310 is ejected in a fiber shape at a flow rate of 0.2 mL / h to 1.5 mL / h from a spinning port such as a needle provided in a syringe, which is applied in a voltage range of 10 kV to 40 kV. The ejected fiber-like polymer solution 310 reaches the grounded collector 410 and is collected.

  The distance D from the tip of the syringe (that is, the spinneret) to the collector 410 is preferably 2 cm or more and 10 cm or less. If the distance is 2 cm or less, the distance D is too short, so the polymer solution 310 may not be in the form of a fiber. If it exceeds 10 cm, the fiber diameter becomes large and non-uniform, which is not preferable.

  The concentration of the polymer solution 310 can be adjusted as appropriate depending on the selected synthetic resin, solvent, and combinations thereof. The resin content is adjusted to be more than 5% by mass and 15% by mass or less, and more than 5% by mass and 15% by mass or less, respectively. Thereby, when the polymer solution 310 ejected from the syringe is collected by the collector 410, the polymer solution 310 can contain a carbon porous body having a functional group in the fiber.

  The solvent of polymer solution 310 is preferably a combination of DMF and THF. Thereby, when the polymer solution 310 ejected from the syringe is collected by the collector 410, the polymer solution 310 can be in a fiber shape. When the amount of DMF is larger than that of THF, a uniform fiber (for example, the fiber diameter is 50 nm or more and 1 μm or less) is preferable.

  As described above, the film-like or fiber-like aromatic amine adsorbent according to the present invention can be produced by the method shown in FIG. 3 or FIG.

  Since the aromatic amine adsorbent of the present invention is made of a synthetic resin containing a carbon porous body having a functional group, only the aromatic amine can be adsorbed to the carbon porous body by the functional group. As a result, it can function as an adsorbent specialized for aromatic amines. If such an adsorbent is supported on a quartz resonator, a gas sensor for detecting a minute amount of aromatic amine can be obtained.

(Embodiment 2)
In the second embodiment, a quartz resonator gas sensor using an aromatic amine adsorbent according to the present invention will be described in detail.

  FIG. 5 is a schematic view of a crystal resonator gas sensor according to the present invention.

  FIG. 5A is a front view of a crystal resonator (QCM) gas sensor 500 according to the present invention, and FIG. 5B is a side view of the QCM gas sensor 500 according to the present invention. In the QCM gas sensor 500 according to the present invention, the aromatic amine adsorbent 520 described in the first embodiment is applied to the crystal resonator (QCM) electrode 510.

  Specifically, the QCM electrode 510 includes a quartz crystal substrate 530, electrodes 540 and 540 'formed on the front and back main surfaces thereof, and lead wires 550 and 550' connected to the electrodes 540 and 540 ', respectively. The quartz substrate 530 is a substantially disc-shaped AT cut substrate. The electrodes 540 and 540 'are electrodes such as gold, platinum, chromium, and nickel formed by physical vapor deposition. The lead wires 550 and 550 ′ are connected to an AC power source or the like, and can be connected to a frequency counter or the like that can apply a potential to the crystal substrate 530 and measure a change in frequency. The aromatic amine adsorbent 520 is applied on at least one of the electrodes 540, 540 ', but may be formed on both electrodes 540, 540'.

  The operation of the QCM gas sensor 500 of the present invention will be described. A potential is applied to the quartz crystal substrate 530 through the lead wires 550 and 550 ′ of the QCM gas sensor 500 and the electrodes 540 and 540 ′. Thereby, the quartz substrate 530 vibrates at a predetermined resonance frequency by thickness shear vibration. Here, when a gas containing an aromatic amine is passed through the QCM gas sensor 500, the aromatic amine in the gas is adsorbed by the aromatic amine adsorbent 520. As a result, an energy loss corresponding to the mass of the adsorbed aromatic amine occurs, so that the predetermined resonance frequency changes. The frequency change is measured by a frequency counter or the like via the lead wires 550 and 550 '. Thus, by using the QCM gas sensor 500 of the present invention, it is possible to detect an aromatic amine in the gas by changing the frequency.

  The QCM gas sensor 500 of the present invention can be easily manufactured by using the QCM electrode 510 as a base material in the method for manufacturing an aromatic amine adsorbent described in Embodiment 1 with reference to FIGS.

  The QCM gas sensor 500 of the present invention may be connected to an AC power source, an amplifier, a frequency counter, etc. to construct a crystal resonator gas sensor device.

  The present invention will now be described in detail using specific examples, but it should be noted that the present invention is not limited to these examples.

[Example 1]
In Example 1, an aromatic amine adsorbent (CNC / PMMA cast membrane) in which caged carbon porous material (CNC) is contained as a carbon porous material having a functional group in film-like polymethyl methacrylate (PMMA) as a synthetic resin. Called).

CNC uses a cage-type silica porous material KIT-5 as a template and is disclosed in Japanese Patent No. 4724877 or Ariga et al. Am. Chem. Soc. , 2007, 129, 11022-11023. The obtained CNC had a specific surface area (BET specific surface area) of 1600 m ² / g and a specific pore volume of 2.1 cm ³ / g. The pore diameter and cage diameter of the CNC were 5.2 nm and 15.0 nm, respectively.

  After preparing the polymer solution, the polymer solution was added dropwise to the crystal resonator (QCM) electrode as a base material by dropping the polymer solution by a casting method to produce a CNC / PMMA cast film (FIG. 3).

  The specific procedure is as follows. The QCM electrode was ultrasonically washed with an aqueous solution consisting of potassium hydroxide (1.0 g), 2-propanol (60 g) and pure water (17.2 MΩ, 40 g) for 3 minutes. Next, the QCM electrode was ultrasonically cleaned with pure water for 1 minute. After washing, the QCM electrode was heated at 50 ° C. for 30 minutes and completely dried.

  As a solvent, CNC (0.10% by mass) and PMMA (0.15% by mass, manufactured by Wako Pure Chemical Industries, Ltd.) are dissolved in N, N-dimethylformamide (DMF, manufactured by Wako Pure Chemical Industries, Ltd.) A polymer solution was prepared.

  A polymer solution (0.7 μL) was dropped on the washed QCM electrode and dried at 50 ° C. As a result, DMF was removed, and a CNC / PMMA cast film was manufactured on the QCM electrode. The mass of the obtained film was about 1700 ng.

  The surface of the CNC / PMMA cast film was observed with a scanning electron microscope (SEM, Hitachi SU-8000). The acceleration voltage at the time of observation was 5 kV. The result is shown in FIG.

  A gas sensor device was designed using a QCM electrode with a CNC / PMMA cast film (ie, a QCM gas sensor). As shown in FIG. Using a gas sensor device, the frequency change with respect to aniline (manufactured by Sigma-Aldrich) as an aromatic amine was measured. Measurement conditions were 10 MHz for AT-cut quartz. The response constant (Hz / ppm) was determined from the frequency change (Hz) for aniline 3-12 ppm. The results are shown in FIG.

  Next, the chemical analysis of CNC was conducted, and the structure of chemical adsorption between CNC and aniline was examined. The infrared absorption spectrum (IR spectrum) of CNC was measured using NEXUS670-FT-IR (Thermo Nicolet). The Raman spectrum of CNC was measured using a micro-Raman system (NRS-1000, JASCO) equipped with a semiconductor laser having a wavelength of 532 nm. The CNC was subjected to X-ray photoelectron spectroscopy (XPS). XPS measurements were performed with MgKα excitation (VG Scientific, ESCALAB 200-X with ECLIPSE data system). The binding energy of the XPS spectrum was calibrated using the Si2p peak (99.3 eV) from the Si (100) substrate as a standard sample. These results are shown in FIGS.

  Next, the chemical adsorption structure of aniline to CNC was examined using density functional theory (DFT), and high selective adsorption of aniline by CNC was considered. The mode by the interaction between CNC and aniline was calculated using density functional molecular dynamics method (DFMD). In DFMD, a CPMD code (CPMD V3.15.1: IBM Research division, MPI Festkoerperschung Stuttgart: Steckgart: Beck functional (Becke's exchange energy formula and Lee, Yang, Parr's correlation energy formula)) /Www.cpmd.org) was used. The Kohn-Sham orbit was expanded by a plane wave with energy cut-off at 70 Ry, and the total energy was calculated only for the Γ point of the superlattice method.

  For all atoms, the Trouller-Martin norm-conserving pseudopotential was adopted. For a canonical (VNT) ensemble, a temperature control of 300K Nose-Hoover was used. The time step was set to 5 (au). In Car-Parrinello dynamics, the provisional mass of electrons was 500 (au). A cubic lattice with a size of 30 × 30 × 30 mm was used.

After 1 ps in DFMD, a geometrically optimized initial structure was created by removing aniline molecules that did not interact with the segmented CNC. Here, B3LYP mounted on Gaussian 09 was adopted using 6-31 ^{G *} basic set. The results are shown in FIG. For comparison, a system of benzene and CNC instead of aniline was also calculated.

[Comparative Example 2]
In Comparative Example 2, a PMMA cast film of polymethyl methacrylate (PMMA) was produced as a synthetic resin. The procedure was the same except that CNC was not used in Example 1. In the gas sensor device designed in Example 1, a QCM electrode provided with a PMMA cast film was disposed instead of the CNC / PMMA cast film, and the frequency change with respect to aniline as an aromatic amine was measured. The measurement conditions were the same as in Example 1. The result is shown in FIG.

[Comparative Example 3]
In Comparative Example 3, an AC / PMMA cast film was produced in which activated carbon (AC) was contained in the film-like polymethyl methacrylate (PMMA) as a synthetic resin instead of the carbon porous body having a functional group. The procedure was the same as in Example 1 except that AC was used instead of CNC. Charcoal active powder (Wako Pure Chemical Industries, Ltd.) was used as AC.

  The surface of the obtained AC / PMMA cast film was observed by SEM in the same manner as in Example 1. In the gas sensor device designed in Example 1, a QCM electrode provided with an AC / PMMA cast film was disposed instead of the CNC / PMMA cast film, and the frequency change with respect to aniline as an aromatic amine was measured. The measurement conditions were the same as in Example 1. These results are shown in FIG. 6b and FIG. In the same manner as in Example 1, the IR spectrum, Raman spectrum, and XPS spectrum of AC were measured. The results are shown in FIG.

  Table 1 shows a list of the experimental conditions of the above Examples and Comparative Examples 1 to 3, and the results are described in detail.

  6 is a diagram showing SEM images of samples of Example 1 and Comparative Example 3. FIG.

  6A and 6B are SEM images of the surfaces of the samples of Example 1 and Comparative Example 3, respectively. In either case, it was confirmed that CNC or AC was in the order of several microns and was uniformly dispersed in the PMMA film.

  FIG. 7 is a diagram showing a crystal resonator gas sensor device.

  FIG. 7A shows the external appearance of the crystal resonator (QCM) gas sensor device, FIG. 7B shows the inside of the crystal resonator gas sensor device, and shows the QCM electrode 710 in an enlarged manner. The QCM electrodes 710 were the CNC / PMMA cast film of Example 1, the PMMA cast film of Comparative Example 2, and the AC / PMMA cast film of Comparative Example 3 applied to the QCM electrode, respectively.

As shown in FIG. 7, the QCM electrode 710 was placed in an approximately 5 cm ³ sensor chamber. In the QCM gas sensor device, the QCM oscillated by the oscillation circuit, and the frequency counter measured the resonance frequency. The measured resonance frequency was recorded in a computer (not shown). The humidity and temperature in the sensor chamber were also recorded. The QCM gas sensor device was connected to a gas flow unit, and aniline-containing N ₂ gas was allowed to flow into the sensor chamber in the QCM gas sensor device. The measurement was performed in a sealed gas reservoir unit.

  FIG. 8 is a graph showing response constants for the samples of Example 1 and Comparative Examples 2 to 3 with respect to aniline.

  According to FIG. 8, it was found that the response constant of the CNC / PMMA cast film to aniline is larger than those of the PMMA cast film and the AC / PMMA cast film. Specifically, the R value of the CNC / PMMA cast film was 5.7 Hz / ppm, which was about 4 times that of the AC / PMMA cast film.

  FIG. 9 is a diagram showing IR spectra of CNC and AC.

IR spectra of the CNC, carboxylic acids, lactones, and showed two peaks of 1600 cm ^-1 and 1720 cm ^-1 corresponding to the carbonyl group consisting of acid anhydride. Furthermore, the extremely broad band of 3200 cm ^{−1 to} 3400 cm ⁻¹ is attributed to phenol O—H stretching. In addition, a clear peak near 3000 cm ⁻¹ indicates that the CNC contains C—H units.

  FIG. 10 is a diagram showing Raman spectra of CNC and AC.

According to the Raman spectrum, it was found that there was no clear difference between CNC and AC. Raman spectra of the CNC, 1600 cm ^-1 vicinity tangential (tangential) G band, and, D band derived from defects are observed in the vicinity of 1345cm ^-1, the CNC will contain a substantial amount of the graphene sheet I understood.

  FIG. 11 shows the XPS spectrum (A) of CNC and the XPS spectrum (B) of AC.

In the figure, the spectrum indicated by the dotted line is the original data before analysis. The high-resolution analysis C1s spectrum of AC in FIG. 11B had a strong peak from 284.7 eV sp ² (—C═C—) carbon and a relatively weak peak near 286 eV to 290 eV. These weak peaks are attributed to the carbons of the hydroxy group (—C—OH), carbonyl group (C═O), carboxyl group (—COOH), and ether group (—C—OR).

On the other hand, it was found that the high-resolution analysis C1s spectrum of CNC in FIG. 11A has a higher peak intensity in the vicinity of 286 eV to 290 eV than that of AC. This indicates that CNC contains a considerable amount of functional functional groups such as hydroxy group, carbonyl group, carboxyl group, ether group as well as sp ² carbon (ie, aromatic unit).

  The results of FIG. 11 are summarized in Table 2.

  From FIG. 8 to FIG. 11, a film-like substance made of PMMA as a synthetic resin containing CNC as a carbon porous body having a functional group adsorbs aniline as an aromatic amine and functions as an aromatic amine adsorbent. Confirmed to do. Moreover, it was shown that the functional group suitable for adsorption of the aromatic amine is preferably a functional group selected from the group consisting of a hydroxy group, a carbonyl group, a carboxyl group, and an ether group.

  FIG. 12 is a diagram showing a model of CNC and aniline using the density functional molecular dynamics method (DFMD).

  Here, according to the results of FIGS. 9 to 11, the simple structural model of CNC is a graphene nanosheet having a carbonyl group as a functional group and partially segmented. Molecules that can interact with aniline are C═O, O—H, and 5- or 6-membered π-orbitals. Here, at 300 K, three aniline molecules were placed around segmented graphene nanosheets and density functional molecular dynamics (DFMD) was performed. This result is shown in FIG.

  As shown in FIG. 12 (a), it was found that only one aniline molecule interacts with a carbonyl group (C = O) located at a close position in the CNC model.

FIGS. 12 (b) and (c) show the optimized structural parameters of the CNC-aniline complex and the CNC-benzene complex at the B3LYP / 6-31G ^* level, respectively.

The binding energy between CNC and benzene was calculated to be 12.86 kJmol ⁻¹ . This value was 19.76 kJmol ⁻¹ lower than the binding energy (32.62 kJmol ⁻¹ ) between CNC and aniline. That is, it was found that the benzene molecule was weakly bonded to the carbonyl group (C═O) via the CH—π interaction. From this, it is suggested that CNC selectively adsorbs aniline by a hydrogen bond between the amine group of aniline and the carbonyl group of CNC.

  In addition, since many carbon-based adsorbent materials are known to have high affinity for aromatic molecules due to π-π interactions, in addition to the hydrogen bonds described above, π-π interactions also occur. Further, it can be considered that a carbon porous body having a functional group such as CNC used in the present invention is imparted with a high selective adsorption ability for an aromatic amine typified by aniline.

[Reference Example 4]
In Reference Example 4, the electrospinning method was used to examine the PMMA concentration and the distance D from the tip of the syringe to the collector for forming polymethyl methacrylate (PMMA) as a synthetic resin into a fiber shape. The polymer solution was prepared by dissolving PMMA in N, N-dimethylformamide (DMF) as a solvent. The concentrations of PMMA in the polymer solution were 5% by mass, 10% by mass, 15% by mass, 20% by mass, 25% by mass and 30% by mass, respectively.

The polymer solution thus prepared was electrospun. Specifically, as shown in FIG. 4, a polymer (SS-01P, 1 mL, manufactured by Terumo Corporation) equipped with a needle (NN-2138R, φ = 0.08 mm, manufactured by Terumo Corporation) as a spinneret is polymerized. The solution was filled, and this was connected to the positive electrode of a high-voltage power supply (HAR-50P6, manufactured by Matsusada Precision Co., Ltd.) via a syringe pump (MSP-DT2, manufactured by ASONE Co., Ltd.). A conductive plate with a steel handle was placed about 20 cm away from the syringe and grounded. The steel handle side was placed close to the needle. The conductive plate was provided with a collector for collecting the fiber, and its area was 1 cm ² .

  The amount of polymer solution supplied from the syringe and the applied voltage were 0.5 mL / h and 20 kV, respectively. The distance D from the tip of the syringe to the collector was 10 cm or 3 cm. The obtained sample was observed by SEM in the same manner as in Example 1. The results are shown in FIG. 13 and FIG.

FIG. 13 is a view showing an SEM image of the sample of Reference Example 4.
FIG. 14 is a view showing another SEM image of the sample of Reference Example 4.

  FIGS. 13A to 13E show the PMMA concentrations of 10 mass%, 15 mass%, 20 mass%, 25 mass%, and 30 mass%, respectively, manufactured at a distance D from the tip of the syringe to the collector of 10 cm. It is a SEM image of a sample. The scale bar in the figure indicates 10 μm.

  FIGS. 14 (a) to 14 (e) show PMMA concentrations of 5 mass%, 10 mass%, 15 mass%, 20 mass%, and 30 mass%, respectively, manufactured at a distance D from the tip of the syringe to the collector of 3 cm. It is a SEM image of a sample. The scale bar in the figure indicates 10 μm.

  According to FIGS. 13 and 14, regardless of the distance D, when the PMMA concentration is low, grains tend to be generated in addition to the generation of thin fibers, and when the PMMA concentration is high, fibers having a large diameter are generated. It turns out that there is a tendency to.

  According to FIG. 13, when the distance D is long, the fiber is generated when the PMMA concentration is 20% by mass or more, but the generated fiber is large and coarse in diameter, and when the PMMA concentration is 10% by mass or less, the fiber is formed. Not generated. On the other hand, according to FIG. 14, when the distance D is short, when the PMMA concentration exceeds 15% by mass, the diameter of the fiber is large and rough, and when the PMMA concentration is 5% by mass or less, no fiber is generated.

  From these results, in order to fiberize synthetic resin by electrospinning, the distance D from the tip of the syringe to the collector is preferably as short as 2 cm or more and 10 cm or less, and the concentration of the synthetic resin is 5 mass%. More than 15% by mass was found to be preferable.

[Reference Example 5]
In Reference Example 5, the solvent of the polymer solution for forming polymethyl methacrylate (PMMA) as a synthetic resin into a fiber shape was examined using an electrospinning method. In Reference Example 5, based on the result of Reference Example 4, the distance D was 3 cm, and the concentration of PMMA as a synthetic resin was 10% by mass. Tetrahydrofuran (THF, manufactured by Wako Pure Chemical Industries, Ltd.) was used in addition to DMF as a solvent. There were two weight ratios of DMF and THF: 7: 3 and 5: 5. The amount of polymer solution supplied from the syringe and the applied voltage were 0.5 mL / h and 20 kV, respectively, as in Reference Example 4. The obtained sample was observed by SEM in the same manner as in Example 1. The results are shown in FIG.

  FIG. 15 is a view showing an SEM image of the sample of Reference Example 5.

  15 (a) and 15 (b), the distance D from the tip of the syringe to the collector is 3 cm, the PMMA concentration is 10% by mass, and the mass ratio of DMS and THF is 7: 3 and 5: 5 is an SEM image of 5 samples. The scale bar in the figure indicates 10 μm.

  Comparing FIG. 14B and FIG. 15, it was found that a uniform fiber was produced by using THF together with DMF as a solvent. Further, comparing FIGS. 15 (a) and 15 (b), it was found that a more uniform fiber was produced when DMF was higher than THF.

  From these results, in order to fiberize the synthetic resin by electrospinning, the solvent of the polymer solution is preferably a combination of N, N-dimethylformamide (DMF) and tetrahydrofuran (THF), among which DMF is more than THF. A larger number is preferable because a uniform fiber is produced.

[Example 6]
In Example 6, an aromatic amine adsorbent (CNC / PMMA fiber and carbon-containing polymethyl methacrylate (PMMA) as a synthetic resin containing a cage-type carbon porous body (CNC) as a carbon porous body having a functional group. Manufactured).

  As the CNC, the CNC manufactured in Example 1 was used. After preparing the polymer solution, a voltage is applied to the syringe containing the polymer solution by electrospinning, the polymer solution is ejected from the syringe, and is collected by a quartz crystal (QCM) electrode as a collector, and the CNC / PMMA fiber is Manufactured (Figure 4).

  The specific procedure is as follows. The QCM electrode was cleaned in the same manner as in Example 1. A polymer solution was prepared based on Reference Example 4 and Reference Example 5. CNC and PMMA were dissolved in a mixed solvent of DMF and THF (weight ratio of DMF and THF was 7: 3), and these were ultrasonically washed for 10 minutes to obtain a polymer solution. The PMMA content in the polymer solution was 10% by mass, and the CNC content was changed to 5%, 7%, and 10% by mass. A CNC / PMMA fiber was manufactured by electrospinning under the same conditions as in Reference Example 5.

  Similar to Example 1, the surface of the CNC / PMMA fiber was observed with an SEM. Details of the CNC / PMMA fiber were observed with a transmission electron microscope (TEM). These results are shown in FIG.

  A QCM electrode (that is, a QCM gas sensor) equipped with a CNC / PMMA fiber is installed in the QCM gas sensor device designed in Example 1 (FIG. 7), and a frequency change with respect to aniline as an aromatic amine is measured to obtain a response constant. It was. Measurement conditions were 10 MHz for AT-cut quartz. The results are shown in FIG.

Further, the repeated resistance of the CNC / PMMA fiber was examined using a QCM gas sensor device. At room temperature (300 K), the CNC / PMMA fiber was alternately exposed to aniline (7 ppm) and dry N ₂ and the frequency change was measured. The results are shown in FIG.

  Furthermore, using a QCM gas sensor device, the frequency change for various volatile organic compounds (benzene, toluene, cyclohexane, ethanol, water, acetone, acetic acid, ammonia) other than aniline of CNC / PMMA fiber is measured, and the response constant is determined. Asked. The results are shown in FIG.

  Furthermore, the concentration dependency (0 ppm to 50 ppm) of the frequency change with respect to aniline and benzene of the CNC / PMMA fiber was measured using a QCM gas sensor device. About CNC / PMMA fiber, the Langmuir plot of the adsorption isotherm was calculated | required from concentration dependence. These results are shown in FIG.

Furthermore, another repeated resistance of the CNC / PMMA fiber was examined using a QCM gas sensor device. At room temperature (300 K), the CNC / PMMA fiber was alternately exposed to aniline (5 ppm), dry N ₂ and benzene (13 ppm), and the frequency change was measured. The results are shown in FIG.

  A list of the experimental conditions of the above reference examples and Examples 4 to 6 is shown in Table 3, and the results will be described in detail.

  FIG. 16 is a view showing an SEM image of the sample of Example 6.

  16 (a) to (c) show that the weight ratio of PMMA to CNC is 10:10 (1: 1), 10: 7 (1: 0.7) and 10: 5 (1: 0.5), respectively. Is a SEM image of the sample. According to FIG. 16, all fibers were produced. From this, it was found that the weight ratio of the synthetic resin in the aromatic amine adsorbent to the carbon porous body having a functional group satisfies 1: 0.2 or more and 1: 5 or less. Further, if the weight ratio of the synthetic resin to the carbon porous body having a functional group is 1: 0.5 or more and 1: 1 or less, the adsorbent in which the carbon porous body having a functional group is dispersed in the synthetic resin is ensured. Can be obtained. Furthermore, in consideration of the diameter and density of the produced fiber, it was found that the weight ratio of the synthetic resin to the carbon porous body having a functional group is preferably 1: 0.7 or more and 1: 1 or less.

  Referring to the inset (TEM image) of FIG. 16 (b), a carbon honeycomb structure by CNC was confirmed inside the fiber. From this, it was shown that a material containing CNC as a fiber-like synthetic resin in PMMA as a carbon porous body having a functional group was produced by the electrospinning method. Moreover, it confirmed that the diameter of the fiber exists in the range of 50 nm-1 micrometer.

  FIG. 17 is a graph showing response constants of the sample of Example 6 to aniline.

  FIG. 17 shows the results for a CNC / PMMA fiber with a weight ratio of PMMA to CNC of 10: 7. Moreover, in FIG. 17, the result (FIG. 8) of an Example and Comparative Examples 1-3 is shown collectively. According to FIG. 17, it was found that the response constant of the CNC / PMMA fiber to aniline is significantly larger than those of the CNC / PMMA cast film, the PMMA cast film, and the AC / PMMA cast film. Specifically, the R value of the CNC / PMMA fiber was 14.6 Hz / ppm, which was 2.6 times that of the CNC / PMMA cast film. From this, it was shown that the synthetic resin is preferably fiber-like as an aromatic amine adsorbent composed of a synthetic resin containing a carbon porous body having a functional group. This is because the specific surface area of the fiber is larger than that of the membrane, so that the area where aniline can be adsorbed is increased and the sensitivity is improved. Although not shown, it was found that CNC / PMMA fibers having other weight ratios similarly have large response constants with respect to aniline.

  FIG. 18 is a diagram showing the repeated resistance of the sample of Example 6 to aniline.

FIG. 18 is the result for a CNC / PMMA fiber with a weight ratio of PMMA to CNC of 10: 7. According to FIG. 18, the frequency change of the CNC / PMMA fiber increased with flowing aniline and decreased with flowing N ₂ . This indicates that aniline was adsorbed on the CNC / PMMA fiber, the frequency change increased, N ₂ adsorbed aniline was desorbed, and the frequency change decreased. That is, it was shown that the aromatic amine adsorbent of the present invention can be repeatedly used because the adsorbed aromatic amine can be eliminated by flowing N ₂ . Although not shown, other weight ratio CNC / PMMA fibers showed similar behavior.

  FIG. 19 is a diagram showing response constants of the sample of Example 6 for various volatile organic compounds.

  FIG. 19 shows the result of a CNC / PMMA fiber having a weight ratio of PMMA to CNC of 10: 7. According to FIG. 19, the R value for aniline was significantly greater than that for any other volatile organic compound, indicating that the CNC / PMMA fiber is sensitive only to aniline. This also indicates that the synthetic resin containing CNC as a carbon porous body having a functional group functions as an aromatic amine adsorbent that selectively adsorbs only the aromatic amine. Although not shown, other weight ratio CNC / PMMA fibers showed similar behavior.

  FIG. 20 shows the adsorption isotherm (a) of the sample of Example 6 for aniline and benzene and its Langmuir plot (b).

  FIG. 20 shows the results for a CNC / PMMA fiber with a weight ratio of PMMA to CNC of 10: 7. As can be seen from FIG. 20A, the CNC / PMMA fiber adsorbs aniline very strongly compared to benzene. According to FIG. 20B, Langmuir plots for both aniline and benzene showed a linear relationship, and it was found that both aniline and benzene were coated with a monolayer on a CNC / PMMA fiber. Although not shown, other weight ratio CNC / PMMA fibers showed similar behavior.

Furthermore, the coupling constant (K) between the CNC / PMMA fiber and aniline or benzene was calculated from FIG. The coupling constant between the CNC / PMMA fiber and aniline was 1852.1M ⁻¹ , and the coupling constant between the CNC / PMMA fiber and benzene was 36.4M ⁻¹ . The remarkable difference in the binding constants also showed that the aromatic amine adsorbent of the present invention selectively adsorbs aniline.

  FIG. 21 is a diagram showing another repeated resistance of the sample of Example 6 to aniline.

FIG. 21 shows the results for a CNC / PMMA fiber with a weight ratio of PMMA to CNC of 10: 7. In FIG. 21, gas is supplied in the order of benzene (13 ppm), N ₂ , and aniline (5 ppm) for 10 minutes, CNC / PMMA fiber (specifically, a QCM gas sensor device equipped with a QCM electrode having a CNC / PMMA fiber). The frequency change was measured. The interval was 5 minutes.

  According to FIG. 21, when benzene (13 ppm) was flowed at 5, 35 and 65 minutes from the start of measurement, the frequency change was only 10 Hz. On the other hand, when aniline (5 ppm) having a concentration sufficiently lower than that of benzene was flowed at 20, 50, and 80 minutes from the start of measurement, the frequency change was 50 Hz. From this, it was shown that the aromatic amine adsorbent of the present invention can be used repeatedly for a long time.

  The aromatic amine adsorbent according to the present invention can function as an adsorbent that selectively adsorbs only the aromatic amine because only the aromatic amine can be adsorbed to the carbon porous body by the functional group. If such an adsorbent is supported on a quartz resonator, a gas sensor for detecting a minute amount of aromatic amine can be obtained. By using such a gas sensor, it is possible to detect a carcinogenic substance or detect an early stage of a potential lung cancer patient only from a person's breath.

110, 120, 520 Aromatic amine adsorbent 130 Carbon porous body having functional group 140 Synthetic resin 210 Carbon porous body 220 Functional group 310 Polymer solution 410 Collector 500 Quartz crystal (QCM) gas sensor 510, 710 Quartz crystal (QCM) Electrode 530 Crystal substrate 540, 540 ′ Electrode 550, 550 ′ Lead wire

Claims (20)

  An aromatic amine adsorbent comprising a synthetic resin containing a carbon porous body having a functional group.   2. The aromatic amine adsorbent according to claim 1, wherein the functional group is at least one selected from the group consisting of a hydroxy group, a carbonyl group, a carboxyl group, and an ether group.   The aromatic amine adsorbent according to claim 1, wherein the synthetic resin is in a fiber shape, and the carbon porous body is contained in a fiber-shaped synthetic resin.   The aromatic amine adsorbent according to claim 3, wherein the fiber has a diameter of 50 nm or more and 1 μm or less.   The aromatic amine adsorbent according to claim 1, wherein the synthetic resin is in a film form, and the carbon porous body is contained in the film-shaped synthetic resin.   The aromatic amine adsorbent according to claim 1, wherein a mass ratio of the synthetic resin to the porous carbon body is in a range of 1: 0.2 or more and 1: 5 or less. The carbon porous body is a cage-type carbon porous body,
^2. The aromatic amine adsorbent according to claim 1, wherein the cage-type carbon porous body has a specific surface area of 1300 m ² / g or more and a specific pore volume of 1.5 cm ³ / g or more. The carbon porous body is a cage-type carbon porous body,
The aromatic amine adsorbent according to claim 1, wherein the cage carbon porous body has a cage diameter of 5 nm or more and 15 nm or less. The carbon porous body is a cage-type carbon porous body,
2. The aromatic amine adsorbent according to claim 1, wherein the cage-type carbon porous body has a face-centered cubic lattice structure and is manufactured using a silica porous body having a space group of Fm3 m as a template.   The synthetic resin is at least one selected from the group consisting of polymethyl methacrylate (PMMA), polymethyl acrylate (PAA), polydimethylsiloxane (PDMS), polyvinyl acetate, epoxy resin, polystyrene, polycarbonate, polypropylene, polybutadiene, and polyethylene. The aromatic amine adsorbent according to claim 1, wherein two are selected.   The aromatic amine adsorbent according to claim 1, which adsorbs aniline as an aromatic amine.   The method for producing an aromatic amine adsorbent according to claim 1, comprising a step of providing a polymer solution containing a carbon porous body having a functional group and a synthetic resin.   The method according to claim 12, wherein in the applying step, a voltage is applied to a syringe containing the polymer solution by electrospinning, and the polymer solution is ejected from the syringe and collected by a collector.   The method according to claim 13, wherein a distance between the syringe and the collector is 2 cm or more and 10 cm or less.   The method according to claim 13, wherein a content of the synthetic resin and a content of the porous carbon body in the polymer solution are each greater than 5 mass% and not greater than 15 mass%.   The solvent of the polymer solution is at least one selected from the group consisting of N, N-dimethylformamide (DMF), tetrahydrofuran (THF), dichloromethane, chloroform, dioxane, acetone, ethyl acetate, toluene, and benzene. Item 13. The method according to Item 12.   The method of claim 16, wherein the solvent of the polymer solution is a combination of N, N-dimethylformamide (DMF) and tetrahydrofuran (THF).   The method according to claim 12, wherein the applying step drops the polymer solution by a casting method.   A crystal resonator gas sensor, wherein the aromatic amine adsorbent according to claim 1 is applied to a crystal resonator electrode.   The method for manufacturing a quartz resonator gas sensor according to claim 19, comprising applying a polymer solution containing a carbon porous body having a functional group and a synthetic resin to a quartz resonator electrode.