System for concentrating and breaking through air pollutants

Abstract

The present invention relates to an air pollutant concentration and breakthrough system comprising: a core formed of conductive fibers; and a shell formed of a yarn structure by being spun onto the core, wherein the yarn is formed of an adsorbent nanofiber; thereby enabling high accuracy, selectivity, and portable measurement by desorbing a minute amount of pollutant concentrated in the shell through the self-heating of the core.

Description

Technology Field

[0001] The present invention relates to an air pollutant concentration and breakthrough system, characterized in that it concentrates and desorbs trace amounts of air pollutants by a solid-phase trace extraction method, wherein the desorption is achieved by self-heating without a separate heating device. Background Technology

[0002] As public interest in air pollutants, including fine dust, soot, volatile organic compounds, and gases generated during combustion, synthesis, and decomposition, grows and health concerns intensify, regulations on multi-use facilities and household odors are being implemented.

[0003] Trace amounts of gaseous pollutants, both indoors and outdoors, exist in extremely minute quantities below ppm, requiring selective and accurate detection. In particular, effective responses to indoor and outdoor air pollutants are possible only when accompanied by tracking monitoring technology from the source to the receiver. To achieve this, multiple sensors must be installed at various points to detect pollutants in real time, and this comprehensive monitoring enables the identification of the diffusion paths of air pollutants. While universally available, affordable sensors capable of accurately sensing low-concentration pollutants are required to secure numerous detection points from the source to the receiver, current low-cost semiconductor gas sensors are unable to accurately and selectively detect such low-concentration air pollutants.

[0004] NDIR (Non-Dispersive Infra Red) is an optical measurement method capable of analyzing the concentration of specific components by utilizing the fact that gaseous substances have specific absorption spectra for infrared radiation, such as CO, CO2, and NO XFor certain specific gases such as [list of gases], portable detection is possible using mobile communication terminals or smartphones with high precision. Non-patent document 1 discloses a portable NDIR CO2 sensor capable of measuring CO2 concentration in combination with a smartphone. However, the above NDIR sensor has the disadvantage of being large in structure and not inexpensive.

[0005] Solid-phase microextraction (SPME) is a method for detecting trace amounts of gaseous pollutants by analyzing them with GC / MS after contaminant concentration (capture). It is implemented by the Ministry of Environment and can analyze even trace amounts of substances, allowing for the detection of malodorous gases, total volatile organic compounds (TVOC), and hydrocarbons such as formaldehyde (HCHO) in various environmental samples including tap water, sewage, soil, and livestock manure. As an example, Non-Patent Literature 2 quantitatively analyzes VOCs in atmospheric samples using SPME. In this method, the SPME fiber is used as a CAR / PDMS fiber with VOC selectivity, and the adsorption characteristics of the target component are controlled by adjusting the coating component or the amount of coating on the fiber.

[0006] The present invention aims to propose a new air pollutant concentration and breakthrough system that utilizes the above-described solid-phase trace extraction method by introducing a self-heating system to desorb air pollutants concentrated in an adsorbent through self-heating, thereby improving the performance of a gas sensor that can be supplied at a low cost, as well as providing detection accuracy and selectivity, so that minute amounts of unknown pollutants can be measured even in a portable manner. Prior art literature

[0007] Low-power non-dispersive infrared CO2 sensor using an LED light source compatible with smart devices (The Journal of Korean Institute of Communications and Information Sciences '15-08 Vol.40 No.08) Quantitative analysis of volatile organic compounds in gas samples using solid-phase microextraction (J. Kor. Soc. Environ. Eng., 35(12), 906~917, 2013) The problem to be solved

[0008] The present invention provides a core-shell structured air pollutant concentration and breakthrough system that enables portable measurement while detecting minute amounts of air pollutants with high accuracy and selectivity using a solid-state micro-extraction method, comprising: a core formed of conductive fibers; and a shell formed of a yarn structure spun onto the core, wherein the yarn is formed of adsorbent nanofibers; thereby desorbing minute amounts of pollutants concentrated in the shell by the self-heating of the core. means of solving the problem

[0009] To achieve the above objective, the present invention provides an air pollutant concentration and breakthrough system having a core-shell structure, characterized by comprising: a core formed of a conductive fiber; and a shell that is spun onto the core to form a yarn structure, wherein the yarn is formed of an adsorbent nanofiber.

[0010] In one embodiment, the conductive fiber may be composed of one or more selected from carbon nanotubes, carbon black, silver, copper, aluminum, iron, zinc, nickel, polyacetylene, polyaniline, polypyrrole, and thiophene.

[0011] In one embodiment, the system may further include a power unit that supplies electrical energy to the core.

[0012] In one embodiment, the core generates heat by Joule heating, thereby desorbing air pollutants concentrated or adsorbed on the shell.

[0013] In one embodiment, the adsorbent nanofiber may further include particles having adsorption properties inside and / or outside thereof, and preferably, the adsorbent nanofiber may be one or more selected from polydimethylsiloxane (PDMS), polyacrylate (PA), carbowax (CW) / divinylbenzene (DVB), carbowax (CW) / templated resin (TPR), polydimethylsiloxane (PDMS) / divinylbenzene (DVB), carboxyl (CAR) / polydimethylsiloxane (PDMS), and divinylbenzene (DVB) / carboxyl (CAR) / polydimethylsiloxane (PDMS).

[0014] In addition, the present invention provides a method for detecting air pollutants, comprising: a) a step of preparing an air pollutant concentration and breakthrough system comprising a core of a conductive fiber and a shell of an adsorbent nanofiber having a yarn structure; b) a step of allowing an air pollutant to be adsorbed and concentrated by the system; c) a step of allowing electricity to flow through the core fiber after a certain degree of concentration is achieved in step b), thereby causing the air pollutant to be desorbed by electric heating; and d) a step of detecting the desorbed air pollutant using a detection device.

[0015] In one embodiment, step b) can be performed while allowing the atmosphere to flow toward the shell side of the concentration and breakthrough system.

[0016] In one embodiment, the desorption of step c) can be performed while flowing a carrier gas.

[0017] In one embodiment, the detection device may be a portable detection sensor. Effects of the invention

[0018] The system of the present invention is formed with a core-shell composite structure, wherein the shell is formed into a yarn structure by spinning adsorbent nanofibers, and the size and volume of the pores between the nanofibers forming the yarn structure can be arbitrarily designed, and gas can be rapidly diffused (moved) through the pores formed by the pores to effectively adsorb and concentrate minute amounts of air pollutants.

[0019] In addition, the present invention generates heat through Joule heating when voltage is applied to a conductive fiber formed as a core, so air pollutants adsorbed and concentrated in the shell can be detached (broken down) without an external heating device, and thus can be used as a portable device.

[0020] In addition, since the bonding of the core and shell is achieved by spinning adsorbent nanofibers into the core, no additional processes such as a separate binder or sintering are required, which can simplify the manufacturing process. Brief explanation of the drawing

[0021] FIG. 1 shows an air pollutant concentration and breakthrough system according to one embodiment of the present invention. Specific details for implementing the invention

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by a skilled expert in the art to which this invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

[0023] Throughout this specification, when a part is described as "comprising" a certain component, this means that, unless specifically stated otherwise, it does not exclude other components but may include additional components. The present invention will be described in detail below.

[0024] In one aspect, the present invention provides an air pollutant concentration and breakthrough system having a core-shell structure, characterized by comprising: a core formed of a conductive fiber; and a shell that is spun onto the core to form a yarn structure, wherein the yarn is formed of an adsorbent nanofiber.

[0025] FIG. 1 shows an air pollutant source concentration and breakthrough system according to one embodiment of the present invention, and will be described in detail with reference thereto.

[0026] In the present invention, the core is formed of a conductive fiber, and Joule heating is possible.

[0027] Joule heating refers to the generation of thermal energy through the passage of current through an electrical conductor. Since the core formed of the conductive fiber can self-heat when voltage is applied, it enables pulse-type, highly responsive temperature control for instantaneously applied voltage.

[0028] Specifically, the conductive fiber is a material capable of generating heat when voltage is applied, and may be a carbon fiber, metal fiber, alloy fiber, conductive polymer fiber, etc. composed of one or more selected from carbon nanotubes, carbon black, silver, copper, aluminum, iron, zinc, nickel, polyacetylene, polyaniline, polypyrrole, and thiophene, but is not limited thereto; however, preferably, the conductive fiber is a conductive fiber capable of Joule heating at 300°C or lower.

[0029] In addition, the conductive fiber is characterized by having a form that can be utilized in a free-standing manner during the pulling or rolling stage in the yarn spinning process, and preferably, it is in the form of a single fiber that is sufficiently thick to be stably utilized in the yarn spinning process, or when thin, it is formed as a bundle of one-dimensional single fibers or has a structure that is twisted together so as to be utilized as a core fiber for yarn spinning.

[0030] The above-mentioned line heating may further include a power unit that supplies electrical energy to the core of the system.

[0031] In the present invention, the shell is formed of an adsorbent nanofiber that is spun onto the core to form a yarn structure. The yarn structure can be formed by spinning the adsorbent nanofiber onto the core by controlling the spinning method, spinning direction, etc., so that the adsorbent nanofiber has a relatively regular directionality or is randomly entangled to form a yarn with a three-dimensional structure.

[0032] Specifically, the yarn structure may be of various forms, such as a structure in which the adsorbent nanofibers form a certain directionality and wrap around the conductive fiber, a structure in which two or more directions are mixed, or a structure in which they are randomly entangled with the conductive fiber to form a three-dimensional structure.

[0033] For example, the yarn structure may be formed by spinning adsorbent nanofibers from both sides around a core formed of conductive fibers capable of wire heating, and a large amount of gas can rapidly diffuse (move) through the fibers forming the yarn structure and the macropores of the fibers to more easily adsorb air pollutants.

[0034] In the present invention, the spinning method is not limited but preferably may be electrospinning, and the adsorbent nanofiber is a component capable of selectively adsorbing or absorbing air pollutants and may be selected considering the component to be adsorbed / absorbed, ease of sample desorption, breakthrough point, etc., and its type is not limited, but as an example, polydimethylsiloxane (PDMS), polyacrylate (PA), carbowax (CW) / divinylbenzene (DVB), carbowax (CW) / templated resin (TPR), polydimethylsiloxane (PDMS) / divinylbenzene (DVB), carboxyl (CAR) / polydimethylsiloxane (PDMS), used in solid-phase micro-extraction (SPME). It may be one or more polymer materials selected from divinylbenzene (DVB), carboxyl (CAR), and polydimethylsiloxane (PDMS).

[0035] In addition, the above-mentioned adsorbent nanofiber may have a material constituting the nanofiber that acts as an adsorbent, or may have adsorbent particles of several nanometers to micrometers in size inserted or bound thereto that can act as an adsorbent on its exterior and / or interior.

[0036] The above adsorbent particles may be one or more selected from magnetic nanosorbents, covalent organic frameworks (COFs), metal-organic frameworks (MOFs), hybrid nanosorbents, molecularly imprinted materials (MIMs), fibers, nanofibers, silica-based nanosorbents, metal oxide nanosorbents, conductive polymers, amorphous silicate sediments, metal-organic nanotube-based composite sponges, nanohydroxyapatite, and layered double hydroxides.

[0037] The air pollutant concentration and breakthrough system having a core-shell composite structure of the present invention adsorbs and concentrates air pollutants by means of a shell with a yarn structure formed by spinning the adsorbent nanofibers, and then applies voltage to a core formed of the conductive fibers, thereby effectively breaking through (desorbing) the air pollutants adsorbed and concentrated in the shell by means of self-heating of the conductive fibers.

[0038] Therefore, unlike conventional solid-phase trace extraction methods that detect air pollutants by GC / MS using external heat inside a chamber, the present invention can destroy (desorb) air pollutants adsorbed and concentrated on the shell by the self-heating of the core forming the system, so the system can be installed in front of existing low-cost sensors, providing accuracy and selectivity and enabling portability.

[0039] In addition, the air pollutant concentration and breakthrough system having a core-shell composite structure of the present invention forms a shell in a yarn structure by spinning adsorbent nanofibers onto a core formed of conductive fibers capable of Joule heating, thereby not requiring additional processes such as binder and sintering to bond the core and the shell, thus simplifying the manufacturing process.

[0040] Afterwards, the above-mentioned air pollutant is analyzed using a detection sensor, GC, or mass spectrometer, etc., to analyze the concentration and type of the air pollutant.

[0041] In addition, the present invention provides a method for detecting air pollutants.

[0042] The method for detecting air pollutants according to the present invention comprises: a) a step of preparing an air pollutant concentration and breakthrough system comprising a core of a conductive fiber and a shell of an adsorbent nanofiber having a yarn structure; b) a step of allowing an air pollutant to be adsorbed and concentrated in the system; c) a step of allowing an air pollutant to be desorbed by electric heating after a certain degree of concentration is achieved in step b); and d) a step of detecting the desorbed air pollutant using a detection device.

[0043] The air pollutant concentration and breakthrough system of step a) above is as described above. The system comprises a step of spinning adsorbent nanofibers from both sides around a core formed of conductive fibers. At this time, the spinning may be performed using a conventional method, and is preferably electrospinning.

[0044] Step b) above is a step in which an air pollutant is adsorbed onto the shell side of the air pollutant concentration and breakthrough system. At this time, it is advantageous for the temperature during adsorption to be as low as possible, but typically, it may be room temperature. The adsorption is intended to increase the concentration of an air pollutant by concentrating it when its atmospheric concentration is low and difficult to detect by conventional methods; the adsorption time may vary depending on the type of air pollutant and its atmospheric concentration. Alternatively, the adsorption time for concentrating the air pollutant can be reduced by allowing the air containing the air pollutant to flow toward the shell side of the concentration and breakthrough system.

[0045] Step c) is a step that facilitates detection in Step d) by breaking through (desorbing) the air pollutants adsorbed on the adsorbent to achieve a higher concentration than in the atmosphere. Therefore, it is advantageous for the concentration of air pollutants to instantaneously raise the temperature to the breakthrough (desorption) temperature during the breakthrough (desorption). The conductive fiber according to the present invention is based on an electrical invention and has the advantage of enabling high-response temperature control in a pulse form by instantaneously applying voltage. In addition, since the nanofiber acting as an adsorbent forms a yarn structure centered on the core of the conductive fiber, a large amount of gas can rapidly diffuse (move) through the fibers and the large pores of the fibers not only during adsorption but also during desorption, thereby further improving the response characteristics. In Step c), a carrier gas may be used to move the broken-through (desorbed) air pollutants; although not limited to the carrier gas, an inert gas may preferably be used. The above breakthrough (desorption) temperature may vary depending on the type of air pollutant, but typically it may be a temperature in the range of 50 to 300 ℃.

[0046] d) Step d is a step of detecting the air pollutant that has been destroyed (defused). Any known type of sensor can be used as the detection means, and preferably, portable detection sensors such as electrochemical sensors, semiconductor sensors, solid electrolyte sensors, photoionization sensors, total reflection sensors, optical sensors (non-dispersive infrared sensors, photoacoustic sensors), etc., are used, but more preferably, a low-cost semiconductor sensor can be utilized as a real-time portable detection device to configure an air pollutant detection device.

[0047] Foregoing, specific parts of the present invention have been described in detail. It will be apparent to those skilled in the art that such specific descriptions are merely preferred embodiments and do not limit the scope of the invention. Accordingly, the substantial scope of the invention is defined by the appended claims and their equivalents.

Claims

Claim 1 An air pollutant concentration and breakthrough system having a core-shell structure, comprising: a core formed of a conductive fiber; and a shell formed of an adsorbent nanofiber that is spun onto the core to form a yarn structure, wherein the yarn is formed of an adsorbent nanofiber capable of selectively adsorbing or absorbing air pollutants; wherein the air pollutants adsorbed or absorbed by the shell are sequentially desorbed in order of proximity to the core by the electric heating of the conductive fiber located in the core, and are finally desorbed in a concentrated state. Claim 2 An air pollutant concentration and breakthrough system according to claim 1, characterized in that the conductive fiber is composed of one or more selected from carbon nanotubes, carbon black, silver, copper, aluminum, iron, zinc, nickel, polyacetylene, polyaniline, polypyrrole, and thiophene. Claim 3 An air pollutant concentration and breakthrough system according to claim 1, characterized in that the system further includes a power unit that supplies electrical energy to a core. Claim 4 An air pollutant concentration and breakthrough system according to claim 1, characterized in that the core generates heat by Joule heating to desorb air pollutants concentrated or adsorbed on the shell. Claim 5 An air pollutant concentration and breakthrough system according to claim 1, characterized in that the adsorbent nanofiber may further include particles having adsorption properties inside and / or outside. Claim 6 An air pollutant concentration and breakthrough system according to claim 1, wherein the adsorbent nanofiber is one or more selected from polydimethylsiloxane (PDMS), polyacrylate (PA), carbowax (CW) / divinylbenzene (DVB), carbowax (CW) / templated resin (TPR), polydimethylsiloxane (PDMS) / divinylbenzene (DVB), carboxyl (CAR) / polydimethylsiloxane (PDMS), and divinylbenzene (DVB) / carboxyl (CAR) / polydimethylsiloxane (PDMS). Claim 7 A method for measuring air pollutants, comprising: a) a step of preparing an air pollutant concentration and breakthrough system having a shell made of adsorbent nanofibers capable of selectively adsorbing or absorbing air pollutants with a core and yarn structure of conductive fibers; b) a step of allowing air pollutants to be adsorbed and concentrated in the system; c) a step of, after a certain degree of concentration is achieved in step b), applying electricity to the core fibers to cause the air pollutants adsorbed or absorbed in the shell to be sequentially desorbed in order of proximity to the core by the electric heating of the conductive fibers located in the core, thereby finally desorbing them in a concentrated state; and d) a step of detecting the desorbed air pollutants using a detection device. Claim 8 A method for detecting an air pollutant according to claim 7, wherein step b) is performed while allowing the air to flow toward the shell side of the concentration and breakthrough system. Claim 9 A method for detecting air pollutants according to claim 7, characterized in that the desorption of step c) above is performed while flowing a carrier gas. Claim 10 A method for detecting air pollutants according to claim 7, characterized in that the detection device is a portable detection sensor.

Images