Water treatment apparatus for decomposing perfluorinated compound on basis of vacuum ultraviolet rays

Abstract

A water treatment apparatus for decomposing a perfluorinated compound on the basis of vacuum ultraviolet rays, according to the present invention, connects a plurality of water treatment pipes each having a vacuum ultraviolet irradiation device in series, so as to sequentially perform oxidation treatment, reduction treatment, and oxidation treatment while water to be treated sequentially passes through the water treatment pipes, thereby being capable of decomposing, among perfluorinated compounds in the water to be treated, fluorotelomers in which carbon (C) and hydrogen (H) are combined as well as perfluoroalkyls in which carbon (C) and fluorine (F) are combined, and bonds between carbon (C) and hydrogen (H) and bonds between carbon (C) and fluorine (F) can both be decomposed in decomposition products additionally generated during oxidation or reduction treatment reactions, and accordingly, through a series of processes, water treatment efficiency can be improved.

Description

Vacuum UV-based perfluorinated compound decomposition water treatment device

[0001] The present invention relates to a vacuum ultraviolet-based perfluorinated compound decomposition water treatment device, and more particularly, to a vacuum ultraviolet-based perfluorinated compound decomposition water treatment device capable of achieving decomposition and defluorination of perfluorinated compounds.

[0002] Water treatment devices are typically designed to remove aquatic pollutants. Perfluorinated compounds, one of these aquatic pollutants, are a group of substances in which hydrogen in the basic hydrocarbon skeleton is replaced by fluorine. They are chemically very stable, resisting degradation and accumulating in living organisms, resulting in toxicity.

[0003] Conventional water treatment devices primarily remove perfluorinated compounds through physical methods such as adsorption or filtration. However, due to limitations, interest in chemical decomposition is growing. However, even with chemical decomposition, the remaining carbon (C) and fluorine (F) bonds in the decomposition products can be ecologically toxic.

[0004] The purpose of the present invention is to provide a vacuum ultraviolet-based perfluorinated compound decomposition water treatment device capable of decomposing and defluorinating perfluorinated compounds.

[0005] The vacuum ultraviolet-based perfluorinated compound decomposition water treatment device according to the present invention comprises: a water inlet pipe for inletting water containing perfluorinated compounds, including perfluoroalkyl substances (PFAS) in which carbon (C) of an alkyl group is saturated with fluorine (F) and fluorotelomer substances in which some of the carbon (C) of an alkyl group is not substituted with fluorine (F) but remains as hydrogen (H); a first oxidation treatment pipe connected to the water inlet pipe and having a first vacuum ultraviolet irradiation device therein, in which an advanced oxidation treatment reaction is performed to break and decompose bonds between carbon (C) and hydrogen (H) in the perfluorinated compounds; A second reduction treatment tube connected to the first oxidation treatment tube and equipped with a second vacuum ultraviolet irradiation device therein, in which an advanced reduction treatment reaction is performed to break bonds between carbon (C) and fluorine (F) in perfluorinated compounds that are not decomposed in the first oxidation treatment tube and to decompose them using vacuum ultraviolet rays and a reducing agent; and a third oxidation treatment tube connected to the second reduction treatment tube and equipped with a third vacuum ultraviolet irradiation device therein, in which the third oxidation treatment tube uses vacuum ultraviolet rays and an oxidizing agent to break bonds between carbon (C) and hydrogen (H) in perfluorinated compounds that are not decomposed in the second reduction treatment tube and to decompose them.

[0006] In the first oxidation treatment tube, vacuum ultraviolet rays generated from the first vacuum ultraviolet irradiation device photolyze water to generate OH radicals, and the OH radicals can break the bonds between carbon (C) and hydrogen (H) in the perfluorinated compound and decompose it.

[0007] The above reducing agent includes sulfite, and in the second reduction treatment tube, vacuum ultraviolet rays generated from the second vacuum ultraviolet irradiation device photolyze the sulfite to generate hydration electrons, and the hydration electrons can defluorinate by breaking the bonds between carbon (C) and fluorine (F) in the perfluorinated compound that was not decomposed in the advanced oxidation treatment reaction of the first oxidation treatment tube and the bonds between carbon (C) and fluorine (F) in the first decomposition product additionally generated in the advanced oxidation treatment reaction.

[0008] The above oxidizing agent includes hydrogen peroxide, and in the third oxidation treatment tube, vacuum ultraviolet rays generated from the third vacuum ultraviolet irradiation device decompose hydrogen peroxide to generate OH radicals, and the OH radicals can decompose by breaking the bonds between carbon (C) and hydrogen (H) in the second decomposition product additionally generated by substituting fluorine (F) with hydrogen (H) in the advanced reduction treatment reaction of the second reduction treatment tube.

[0009] The above vacuum ultraviolet-based perfluorinated compound decomposition water treatment device may further include a first connecting pipe connecting the first oxidation treatment pipe and the second reduction treatment pipe, and a reducing agent injection unit for injecting the reducing agent into the first connecting pipe.

[0010] A pH adjuster for controlling the pH of the water to be treated and nitrogen for removing dissolved oxygen of the water to be treated can be injected into the first connecting pipe.

[0011] The above vacuum ultraviolet-based perfluorinated compound decomposition water treatment device may further include a second connecting pipe connecting the second reduction treatment pipe and the third oxidation treatment pipe, and an oxidizing agent injection unit for injecting the oxidizing agent into the second connecting pipe.

[0012] The above vacuum ultraviolet-based perfluorinated compound decomposition water treatment device may further include a discharge pipe connected to the discharge port of the third oxidation treatment pipe for discharging the treated water from the third oxidation treatment pipe to the outside, and a water quality measuring device provided in the discharge pipe for measuring the water quality of the treated water.

[0013] The above vacuum ultraviolet-based perfluorinated compound decomposition water treatment device may further include a return pipe branched from the discharge pipe and connected to the treatment water inlet pipe, for recovering some of the treated water discharged to the discharge pipe to the treatment water inlet pipe when the water quality measured by the water quality measuring device exceeds a preset standard, and a return pipe valve for opening and closing the return pipe.

[0014] The reducing agent includes sulfite, the oxidizing agent includes hydrogen peroxide, and the water quality measuring device can measure the concentration of fluoride ions, hydrogen peroxide, and sulfite ions in the treated water.

[0015] According to another embodiment of the present invention, a vacuum ultraviolet-based perfluorinated compound decomposition water treatment device comprises: a water inlet pipe for inletting water containing a perfluorinated compound, the water containing perfluorinated compound including at least one of a perfluoroalkyl substance (PFAS) in which carbon (C) of an alkyl group is saturated with fluorine (F) and a fluorotelomer in which some of the carbon (C) of an alkyl group is not substituted with fluorine (F) but remains as hydrogen (H); a first oxidation treatment pipe connected to the water inlet pipe and having a first vacuum ultraviolet lamp therein, in which an advanced oxidation treatment reaction is performed to break and decompose bonds between carbon (C) and hydrogen (H) in the perfluorinated compound using vacuum ultraviolet rays; A second reduction treatment tube connected in series to the first oxidation treatment tube and equipped with a second vacuum ultraviolet lamp therein, wherein an advanced reduction treatment reaction is performed to defluorinate and break bonds between carbon (C) and fluorine (F) in perfluorinated compounds that are not decomposed in the first oxidation treatment tube using vacuum ultraviolet rays and a reducing agent; A third oxidation treatment tube connected in series to the second reduction treatment tube and equipped with a third vacuum ultraviolet lamp therein, wherein the third oxidation treatment tube uses vacuum ultraviolet rays and an oxidizing agent to break bonds between carbon (C) and hydrogen (H) in perfluorinated compounds that are not decomposed in the second reduction treatment tube and decompose them; A first connecting tube connecting between the first oxidation treatment tube and the second reduction treatment tube, a reducing agent injection unit for injecting the reducing agent into the first connecting tube; A second connecting tube connecting between the second reduction treatment tube and the third oxidation treatment tube;An oxidizing agent injection unit for injecting the oxidizing agent into the second connecting tube is included, the reducing agent includes sulfite, the oxidizing agent includes hydrogen peroxide, in the first oxidation treatment tube, vacuum ultraviolet rays generated from the first vacuum ultraviolet lamp photolyze water to generate OH radicals, and the OH radicals break the bonds between carbon (C) and hydrogen (H) in the perfluorinated compound and decompose it, in the second reduction treatment tube, vacuum ultraviolet rays generated from the second vacuum ultraviolet lamp photolyze the sulfite to generate hydration electrons, and the hydration electrons break the bonds between carbon (C) and fluorine (F) in the perfluorinated compound that was not decomposed in the advanced oxidation treatment reaction of the first oxidation treatment tube and the bonds between carbon (C) and fluorine (F) in the first decomposition product additionally generated in the advanced oxidation treatment reaction and defluorinate it, and in the third oxidation treatment tube, vacuum ultraviolet rays generated from the third vacuum ultraviolet lamp Hydrogen peroxide is decomposed to generate OH radicals, and the OH radicals break the bonds between carbon (C) and hydrogen (H) in the second decomposition product additionally generated by substituting fluorine (F) with hydrogen (H) in the advanced reduction treatment reaction, thereby decomposing it.

[0016] The vacuum ultraviolet-based perfluorinated compound decomposition water treatment device according to the present invention sequentially performs oxidation treatment, reduction treatment, and oxidation treatment while a plurality of water treatment pipes, each equipped with a vacuum ultraviolet lamp, are connected in series so that water to be treated passes through the water treatment pipes sequentially, thereby enabling the decomposition of not only perfluoroalkyls in which carbon (C) and fluorine (F) are combined, but also fluorotelomers in which carbon (C) and hydrogen (H) are combined, among perfluorinated compounds in the water to be treated, and since both bonds of carbon (C) and hydrogen (H) and bonds of carbon (C) and fluorine (F) can be decomposed in the decomposition products additionally generated during the oxidation or reduction treatment reaction, the efficiency of water treatment can be improved through a series of processes.

[0017] FIG. 1 is a schematic drawing of a vacuum ultraviolet-based perfluorinated compound decomposition water treatment device according to an embodiment of the present invention.

[0018] Figure 2 is a drawing sequentially illustrating the water treatment steps in the water treatment device illustrated in Figure 1.

[0019] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

[0020] A vacuum ultraviolet-based perfluorinated compound decomposition water treatment device according to an embodiment of the present invention is a device for treating water by decomposing perfluorinated compounds contained in water to be treated.

[0021] The above perfluorinated compounds include perfluoroalkyl substances (PFAS) in which the carbon (C) of the alkyl group is saturated with fluorine (F), and fluorotelomer substances in which some of the carbons (C) of the alkyl group are not substituted with fluorine (F) but remain as hydrogen (H).

[0022] FIG. 1 is a schematic diagram of a vacuum ultraviolet-based perfluorinated compound decomposition water treatment device according to an embodiment of the present invention. Referring to FIG. 1, the vacuum ultraviolet-based perfluorinated compound decomposition water treatment device according to an embodiment of the present invention includes a treatment water inlet pipe (1), a first oxidation treatment pipe (10), a second reduction treatment pipe (20), a third oxidation treatment pipe (30), a first connecting pipe (15), a second connecting pipe (25), a discharge pipe (40), a return pipe (50), a reducing agent injection unit (100), and an oxidizing agent injection unit (200).

[0023] The above-mentioned treatment water inlet pipe (1) is a pipe through which treatment water containing the perfluorinated compound flows.

[0024] The above first oxidation treatment pipe (10) is a water treatment pipe that is connected in series to the water inlet pipe (1) to be treated, and is equipped with a first vacuum ultraviolet lamp (12) as a first vacuum ultraviolet irradiation device inside. The first oxidation treatment pipe (10) is described as being formed as a stainless steel pipe so as not to be deformed by ultraviolet rays, but is not limited thereto, and can be applied by changing it in various ways as long as it is a material that is not deformed by ultraviolet rays. In the above first oxidation treatment pipe (10), pollutants are photodecomposed by vacuum ultraviolet (VUV) generated from the first vacuum ultraviolet lamp (12), and an advanced oxidation treatment reaction is performed to break the bonds between carbon (C) and hydrogen (H) in the perfluorinated compound and decompose it using the OH radicals generated during the photodecomposition.

[0025] The first vacuum ultraviolet lamp (12) is arranged lengthwise in the center of the first oxidation treatment tube (10).

[0026] The second reduction treatment pipe (20) is a water treatment pipe that is connected in series to the first oxidation treatment pipe (10) so that the treated water from the first oxidation treatment pipe (10) flows in. The second reduction treatment pipe (20) is equipped with a second vacuum ultraviolet lamp (22) as a second vacuum ultraviolet irradiation device inside. The second reduction treatment pipe (20) is described as being formed as a stainless steel pipe so as not to be deformed by ultraviolet rays, but is not limited thereto and can be applied by changing it in various ways as long as it is a material that is not deformed by ultraviolet rays. In the second reduction treatment pipe (20), the vacuum ultraviolet rays generated from the second vacuum ultraviolet lamp (22) photolyze sulfite, which is a reducing agent described later, to generate hydration electrons. The above-mentioned hydration electrons break the bonds between carbon (C) and fluorine (F) in the perfluorinated compound that is not decomposed in the first oxidation treatment tube (10) and decompose it, and break the bonds between carbon (C) and fluorine (F) in the first decomposition product additionally generated after decomposition in the advanced oxidation treatment reaction of the first oxidation treatment tube (10) and defluorinate it, so that an advanced reduction treatment reaction occurs in the second reduction treatment tube (20).

[0027] The above second vacuum ultraviolet lamp (22) is arranged lengthwise in the center of the second reduction treatment tube (20).

[0028] The third oxidation treatment pipe (30) is a water treatment pipe that is connected in series to the second reduction treatment pipe (20) so that the treated water from the second reduction treatment pipe (20) flows into it. The third oxidation treatment pipe (30) is equipped with a third vacuum ultraviolet lamp (33) as a third vacuum ultraviolet irradiation device inside. The third oxidation treatment pipe (30) is described as being formed as a stainless steel pipe so as not to be deformed by ultraviolet rays, but is not limited thereto and can be applied by changing it in various ways as long as it is a material that is not deformed by ultraviolet rays. In the third oxidation treatment pipe (30), vacuum ultraviolet rays generated from the third vacuum ultraviolet lamp (32) decompose hydrogen peroxide, which is an oxidizing agent described later, to generate OH radicals. The OH radical generated in the third oxidation treatment tube (30) breaks the bond between carbon (C) and hydrogen (H) in the perfluorinated compound that is not decomposed in the second reduction treatment tube (20) and the bond between carbon (C) and hydrogen (H) in the second decomposition product that is additionally generated by replacing fluorine (F) with hydrogen (H) in the advanced reduction treatment reaction, thereby defluorinating the compound, and thus an advanced oxidation treatment reaction occurs in the third oxidation treatment tube (30).

[0029] The third vacuum ultraviolet lamp (32) is arranged lengthwise in the center of the third oxidation treatment tube (30).

[0030] Meanwhile, the first oxidation treatment pipe (10) and the second reduction treatment pipe (20) are connected by the first connecting pipe (15). The first connecting pipe (15) is a flow path that connects in series between the outlet of the first oxidation treatment pipe (10) and the inlet of the second reduction treatment pipe (20). The first connecting pipe (15) is equipped with a reducing agent injection part (100) for injecting the reducing agent.

[0031] The reducing agent is sulfite, for example. Sulfite is SO3 2-It is an inorganic salt of sulfurous acid. In this embodiment, sodium sulfite (Na2SO3) is used as the reducing agent, as an example. However, the present invention is not limited thereto, and it is also possible to add iodine ions, indoel, and dithionite in addition to sulfurous acid ions.

[0032] In addition, a pH adjuster is injected into the first connecting pipe (15) to adjust the pH of the treated water coming from the first oxidation treatment pipe (10). As an example, the pH adjuster is sodium hydroxide (NaOH). In this embodiment, the pH adjuster is injected through the reducing agent injection unit (100) as an example. However, the present invention is not limited thereto, and the pH adjuster may be injected through an injection unit provided separately from the reducing agent injection unit (100) or may be directly injected into the second reduction treatment pipe (20). In addition, a nitrogen injection unit (101) is provided in the first connecting pipe (15).

[0033] The above nitrogen injection unit (101) injects nitrogen (N2) to remove dissolved oxygen in the water to be treated from the first oxidation treatment tube (10). In this embodiment, nitrogen (N2) is injected through a nitrogen injection unit (101) provided separately from the reducing agent injection unit (100), but the present invention is not limited thereto. Nitrogen (N2) may be injected together through the reducing agent injection unit (100), and of course, it is also possible to directly inject it into the second reduction treatment tube (20). Meanwhile, the second reduction treatment tube (20) and the third oxidation treatment tube (30) are connected by the second connecting pipe (25). The second connecting pipe (25) is a path that connects in series between the outlet of the second reduction treatment tube (20) and the inlet of the third oxidation treatment tube (30). The second connecting pipe (25) is provided with an oxidizing agent injection part (20) for injecting the oxidizing agent. The oxidizing agent is hydrogen peroxide (H2O2) as an example. However, the invention is not limited thereto, and it is of course also possible to add hypochlorous acid (HOCl), persulfate, etc. in addition to hydrogen peroxide.

[0034] Meanwhile, the discharge pipe (40) is connected to the outlet of the third oxidation treatment pipe (30). The discharge pipe (40) is a conduit for discharging the treated water from the third oxidation treatment pipe (30) to the outside. The discharge pipe (40) is equipped with a water quality measuring device (300) for measuring the water quality of the treated water before it is discharged to the outside. The water quality measuring device (300) measures the concentration of fluoride ions, hydrogen peroxide, and sulfite ions in the treated water, respectively.

[0035] The above-mentioned return pipe (50) is a path that branches from the discharge pipe (40) at a point where the water quality measuring device (300) is installed or at a point downstream from the water quality measuring device (300) and is connected to the treatment water inlet pipe (1). The return pipe (50) is a path for recovering a portion of the treated water discharged to the discharge pipe to the treatment water inlet pipe (1) when the water quality measured by the water quality measuring device (300) exceeds a preset standard. The return pipe (50) is provided with a return pipe valve (not shown) for opening and closing the return pipe (50) depending on the water quality measured by the water quality measuring device (300).

[0036] The above water treatment device further includes a control unit (not shown) that controls the operation of the return pipe valve (not shown) according to the water quality measured by the water quality measuring device (300). The control unit (not shown) can also, of course, adjust the amount injected from the reducing agent injection unit (100), the nitrogen injection unit (101), and the oxidizing agent injection unit (200) according to the water quality measured by the water quality measuring device (300).

[0037] The operation of the vacuum ultraviolet-based perfluorinated compound decomposition water treatment device is described as follows. Figure 2 is a drawing sequentially illustrating the water treatment steps in the water treatment device illustrated in Figure 1.

[0038] The above vacuum ultraviolet-based perfluorinated compound decomposition water treatment device sequentially performs a first oxidation treatment step (STEP 1), a second reduction treatment step (STEP 2), and a third oxidation treatment step (STEP 3).

[0039] Referring to FIGS. 1 and 2, the water to be treated that has entered the water to be treated inlet pipe (1) passes through the first oxidation treatment pipe (10). In the first oxidation treatment pipe (10), the first oxidation treatment step (STEP 1) is performed.

[0040] The above first oxidation treatment step (STEP 1) is a step in which an advanced oxidation treatment reaction takes place in which vacuum ultraviolet rays generated from the first vacuum ultraviolet lamp (12) in the first oxidation treatment tube (10) photolyze water to generate OH radicals, and the OH radicals break the bonds between carbon (C) and hydrogen (H) in the perfluorinated compounds contained in the water to be treated and decompose them. Chemical formulas 1 and 2 are reaction formulas representing the vacuum ultraviolet reaction.

[0041]

[0042]

[0043] Table 1 schematically shows the substances and decomposition products that are decomposed during the water treatment stage depending on the perfluorinated compound.

[0044]

[0045] Referring to Table 1, perfluorinated compounds contained in the treated water include, depending on the structure, perfluoroalkyl substances (PFAS) in which all carbons (C) of the alkyl group are saturated with fluorine (F), and fluorotelomers in which some of the carbons (C) are not substituted with fluorine (F) and remain as hydrogen (H).

[0046] In the advanced oxidation treatment reaction that occurs in the first oxidation treatment step (STEP1), only the bonds between carbon (C) and hydrogen (H) of the fluorotelomer can be decomposed, and the perfluoroalkyl substance in which carbon (C) is saturated with fluorine (F) is not decomposed.

[0047] In the first oxidation treatment step (STEP1), a first decomposition product is generated. The first decomposition product is a substance in which carbon (C) and fluorine (F) are combined. In the advanced oxidation treatment reaction, the bond between carbon (C) and hydrogen (H) of the fluorotelomer is broken down, and the bond between carbon (C) and fluorine (F) remains, resulting in a perfluoroalkyl substance. That is, the fluorotelomer is a substance in which some of the carbon (C) of the alkyl group is not substituted with fluorine (F) but remains as hydrogen (H), so that a bond between carbon (C) and hydrogen (H) and a bond between carbon (C) and fluorine (F) exist. In the first oxidation treatment step (STEP1), the bond between carbon (C) and hydrogen (H) is broken down by the oxidation treatment reaction, and a perfluoroalkyl substance in which a bond between carbon (C) and fluorine (F) remains is generated. Accordingly, while passing through the first oxidation treatment pipe (10), perfluorinated compounds remain in the oxidation-treated treatment water, and perfluoroalkyl substances in which carbon (C) and fluorine (F) are combined that are not decomposed in the oxidation treatment reaction of the first oxidation treatment step (STEP1), and first decomposition products in which carbon (C) and fluorine (F) are combined that are additionally generated during the oxidation treatment process are included.

[0048] Meanwhile, the treated water that has undergone oxidation treatment in the first oxidation treatment tube (10) flows into the second reduction treatment tube (20). The reducing agent, the pH adjuster, and nitrogen (N2) are injected between the first oxidation treatment tube (10) and the second reduction treatment tube (20). In this embodiment, the reducing agent is sodium sulfite (Na2SO3), and the pH adjuster is sodium hydroxide (NaOH), as an example. The second reduction treatment step (STEP 2) is performed in the second reduction treatment tube (20). In the second reduction treatment tube (20), the pH of the treated water is adjusted to alkaline by the pH adjuster, and dissolved oxygen is removed by the nitrogen.

[0049] Referring to Chemical Formula 3, the second reduction treatment step (STEP 2) is a process in which vacuum ultraviolet rays generated from the second vacuum ultraviolet lamp (22) in the second reduction treatment tube (20) are used to treat sulfurous acid (SO3) 2- ) by photolysis to produce hydrated electrons (e aq -) is generated, and a high-level reduction treatment reaction is performed in which pollutants are decomposed by the hydration electrons. The hydration electrons generated in the second reduction treatment pipe (20) break the bonds between carbon (C) and fluorine (F) in the perfluorinated compound contained in the treated water, thereby defluorinating it.

[0050]

[0051] Referring to Table 1, in the advanced reduction treatment reaction that occurs in the second reduction treatment step (STEP 2), the bond between carbon (C) and fluorine (F) can be decomposed, but the bond between carbon (C) and hydrogen (H) cannot be decomposed. In other words, in the advanced reduction treatment reaction, the decomposition of a perfluoroalkyl substance in which carbon (C) and fluorine (F) are combined is possible, but the fluorotelomer substance in which carbon (C) and hydrogen (H) are combined is not decomposed.

[0052] In the above-described advanced reduction treatment reaction, the bond between carbon (C) and fluorine (F) in the first decomposition product generated in the first oxidation treatment step (STEP 1) is broken, and the bond between carbon (C) and fluorine (F) of the perfluoroalkyl remaining without being decomposed in the first oxidation treatment step (STEP 1) is broken, thereby defluorinating. At this time, in the second reduction treatment step (STEP 2), a second decomposition product is generated. The second decomposition product is a material in which carbon (C) and hydrogen (H) are combined. The second decomposition product is a fluorotelomer material in which some of the fluorine (F) is replaced with hydrogen (H) when the bond between carbon (C) and fluorine (F) is decomposed in the above-described advanced reduction treatment reaction, thereby combining carbon (C) and hydrogen (H). Since the fluorotelomer material is not decomposed in the reduction treatment reaction, the third oxidation treatment step (STEP 3) described below is required. That is, in the second reduction treatment step (STEP 2), the bond between carbon (C) and fluorine (F) is broken and defluorinated, but the second decomposition product in the form of a fluorotelomer in which carbon (C) and hydrogen (H) are combined is additionally generated. Therefore, while passing through the second reduction treatment pipe (20), the treated water subjected to reduction treatment contains a perfluorinated compound, and the second decomposition product in which carbon (C) and hydrogen (H) are combined is additionally generated in the reduction treatment reaction of the second reduction treatment step (STEP2).

[0053] Meanwhile, the treated water reduced in the second reduction treatment tube (20) flows into the third oxidation treatment tube (30). The oxidizing agent is injected between the second reduction treatment tube (20) and the third oxidation treatment tube (30). In this embodiment, the oxidizing agent is hydrogen peroxide (H2O2) as an example. The third oxidation treatment step (STEP 3) is performed in the third oxidation treatment tube (30).

[0054] The third oxidation treatment step (STEP 3) is a process in which vacuum ultraviolet rays generated from the third vacuum ultraviolet lamp (32) in the third oxidation treatment tube (30) photolyze the hydrogen peroxide (H2O2) to generate OH radicals and residual sulfite (SO3) 2- ) is removed, and an advanced oxidation treatment reaction is performed to break and decompose the bonds of carbon (C) and hydrogen (H) in the perfluorinated compounds contained in the treated water.

[0055]

[0056] Referring to Table 1, in the advanced oxidation treatment reaction occurring in the third oxidation treatment step (STEP 3), the bond between carbon (C) and hydrogen (H) can be decomposed. That is, in the third oxidation treatment tube (30), the fluorotelomer material, which is the second decomposition product generated in the second reduction treatment tube (20), can be decomposed.

[0057] As described above, in the embodiment of the present invention, as the treatment water sequentially passes through the first oxidation treatment tube (10), the second reduction treatment tube (20), and the third oxidation treatment tube (30), oxidation treatment, reduction treatment, and oxidation treatment are sequentially performed, so that not only the bonds of carbon (C) and hydrogen (H) but also the bonds of carbon (C) and fluorine (F) can be decomposed. That is, among perfluorinated compounds, not only perfluoroalkyl in which carbon (C) and fluorine (F) are bonded but also fluorotelomer in which carbon (C) and hydrogen (H) are bonded can be decomposed, and in the decomposition products additionally generated during the oxidation or reduction treatment reaction, both the bonds of carbon (C) and hydrogen (H) and the bonds of carbon (C) and fluorine (F) can be decomposed.

[0058] Meanwhile, the treated water from the third oxidation treatment pipe (30) flows into the discharge pipe (40). The water quality measuring device (300) measures the water quality of the treated water flowing into the discharge pipe (40). The water quality measuring device (300) measures the fluoride ion concentration, hydrogen peroxide concentration, and sulfite concentration of the treated water, respectively. If at least one of the fluoride ion concentration, hydrogen peroxide concentration, and sulfite concentration measured by the water quality measuring device (300) exceeds a preset standard concentration, the treated water is returned to the treated water inflow pipe (1) through the return pipe (50). Accordingly, the treated water in which at least one of the concentration of the fluoride ion, the concentration of the hydrogen peroxide, and the concentration of the sulfite exceeds the standard concentration can be subjected to additional oxidation and reduction treatments while sequentially passing through the first oxidation treatment tube (10), the second reduction treatment tube (20), and the third oxidation treatment tube (30).

[0059] If at least one of the concentration of the fluoride ion, the concentration of the hydrogen peroxide, and the concentration of the sulfite is below a preset standard concentration for each, it can be discharged to the outside.

[0060] While the present invention has been described with reference to the embodiments illustrated in the drawings, these are merely exemplary, and those skilled in the art will understand that various modifications and equivalent alternative embodiments are possible. Therefore, the true scope of technical protection of the present invention should be determined by the technical spirit of the appended claims.

[0061] Using the present invention, a vacuum ultraviolet-based perfluorinated compound decomposition water treatment device capable of achieving decomposition and defluorination of perfluorinated compounds can be manufactured.

Claims

1. A treatment water inlet pipe that introduces treatment water containing perfluorinated compounds, including perfluoroalkyl substances (PFAS) in which the carbon (C) of the alkyl group is saturated with fluorine (F) and fluorotelomer substances in which some of the carbon (C) of the alkyl group is not replaced with fluorine (F) and remains as hydrogen (H); A first oxidation treatment pipe connected to the above-mentioned treatment water inlet pipe and having a first vacuum ultraviolet irradiation device inside, wherein an advanced oxidation treatment reaction is performed to break and decompose the bonds between carbon (C) and hydrogen (H) in the perfluorinated compound using vacuum ultraviolet rays; A second reduction treatment tube connected to the first oxidation treatment tube and equipped with a second vacuum ultraviolet irradiation device inside, in which an advanced reduction treatment reaction is performed to break and decompose the bonds between carbon (C) and fluorine (F) in the perfluorinated compound that has not been decomposed in the first oxidation treatment tube using vacuum ultraviolet irradiation and a reducing agent; A third oxidation treatment tube is connected to the second reduction treatment tube and has a third vacuum ultraviolet irradiation device installed inside, and uses vacuum ultraviolet irradiation and an oxidizing agent to break and decompose the bonds between carbon (C) and hydrogen (H) in the perfluorinated compound that is not decomposed in the second reduction treatment tube. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

2. In claim 1, In the above first oxidation treatment tube, The vacuum ultraviolet rays generated from the first vacuum ultraviolet irradiation device photolyze water to generate OH radicals, The above OH radical breaks the bond between carbon (C) and hydrogen (H) in the perfluorinated compound and decomposes it. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

3. In claim 1, The above reducing agent contains sulfite, In the above second reduction treatment plant, The vacuum ultraviolet rays generated from the second vacuum ultraviolet irradiation device photodecompose the sulfite to generate hydration electrons, The above hydration electrons break the bonds between carbon (C) and fluorine (F) in the perfluorinated compound that is not decomposed in the advanced oxidation treatment reaction of the first oxidation treatment tube and the bonds between carbon (C) and fluorine (F) in the first decomposition product additionally generated in the advanced oxidation treatment reaction, thereby defluorinating the compound. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

4. In claim 1, The above oxidizing agent includes hydrogen peroxide, In the above third oxidation treatment pipe, The vacuum ultraviolet rays generated from the third vacuum ultraviolet irradiation device decompose hydrogen peroxide to generate OH radicals, The above OH radical breaks the bond between carbon (C) and hydrogen (H) in the second decomposition product additionally generated by replacing fluorine (F) with hydrogen (H) in the advanced reduction treatment reaction of the second reduction treatment tube, thereby decomposing it. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

5. In claim 1, A first connecting pipe connecting the first oxidation treatment pipe and the second reduction treatment pipe, Further comprising a reducing agent injection unit for injecting the reducing agent into the first connecting pipe. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

6. In claim 5, The first connecting pipe above is injected with a pH adjuster to control the pH of the water to be treated and nitrogen to remove dissolved oxygen in the water to be treated. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

7. In claim 1, A second connecting pipe connecting the second reduction treatment pipe and the third oxidation treatment pipe, Further comprising an oxidizer injection unit for injecting the oxidizer into the second connecting pipe. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

8. In claim 1, A discharge pipe connected to the discharge port of the third oxidation treatment pipe for discharging the treated water from the third oxidation treatment pipe to the outside, Further comprising a water quality measuring device installed in the above discharge pipe to measure the water quality of the treated water. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

9. In claim 8, A return pipe branched from the above discharge pipe and connected to the above treatment water inlet pipe, for recovering some of the treated water discharged to the discharge pipe to the treatment water inlet pipe when the water quality measured by the water quality measuring device exceeds a preset standard; Further comprising a return pipe valve for opening and closing the return pipe, Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

10. In claim 9, The above reducing agent contains sulfite, The above oxidizing agent includes hydrogen peroxide, The above water quality measuring device measures the concentration of fluoride ions, hydrogen peroxide, and sulfite ions in the treated water. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

11. In claim 1, The above first vacuum ultraviolet irradiation device includes a first vacuum ultraviolet lamp, The above second vacuum ultraviolet irradiation device includes a second vacuum ultraviolet lamp, The above third vacuum ultraviolet irradiation device includes a third vacuum ultraviolet lamp. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

12. In claim 1, The above second reduction treatment tube is connected in series to the above first oxidation treatment tube, The third oxidation treatment tube is connected in series to the second reduction treatment tube. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

13. A treatment water inlet pipe that introduces treatment water containing a perfluorinated compound including at least one of a perfluoroalkyl substance (PFAS) in which the carbon (C) of the alkyl group is saturated with fluorine (F) and a fluorotelomer in which some of the carbon (C) of the alkyl group is not replaced with fluorine (F) and remains as hydrogen (H); A first oxidation treatment pipe connected to the above-mentioned treatment water inlet pipe and having a first vacuum ultraviolet irradiation device inside, wherein an advanced oxidation treatment reaction is performed to break and decompose the bonds between carbon (C) and hydrogen (H) in the perfluorinated compound using vacuum ultraviolet rays; A second reduction treatment tube connected in series to the first oxidation treatment tube and equipped with a second vacuum ultraviolet irradiation device inside, in which an advanced reduction treatment reaction is performed to break the bonds between carbon (C) and fluorine (F) in the perfluorinated compound that has not been decomposed in the first oxidation treatment tube and defluorinate it using vacuum ultraviolet irradiation and a reducing agent; A third oxidation treatment tube connected in series to the second reduction treatment tube and equipped with a third vacuum ultraviolet irradiation device inside, which uses vacuum ultraviolet irradiation and an oxidizing agent to break and decompose the bonds between carbon (C) and hydrogen (H) in the perfluorinated compound that has not been decomposed in the second reduction treatment tube; A first connecting pipe connecting the first oxidation treatment pipe and the second reduction treatment pipe, A reducing agent injection unit for injecting the reducing agent into the first connecting pipe; A second connecting pipe connecting the second reduction treatment pipe and the third oxidation treatment pipe; Including an oxidizer injection unit that injects the oxidizer into the second connecting pipe, The above reducing agent contains sulfite, The above oxidizing agent includes hydrogen peroxide, In the first oxidation treatment tube, the vacuum ultraviolet rays generated from the first vacuum ultraviolet irradiation device photolyze water to generate OH radicals, and the OH radicals break the bonds between carbon (C) and hydrogen (H) in the perfluorinated compound to decompose it. In the second reduction treatment tube, the vacuum ultraviolet ray generated from the second vacuum ultraviolet irradiation device photolyzes the sulfite to generate hydration electrons, and the hydration electrons break the bonds between carbon (C) and fluorine (F) in the perfluorinated compound that was not decomposed in the advanced oxidation treatment reaction of the first oxidation treatment tube and the bonds between carbon (C) and fluorine (F) in the first decomposition product additionally generated in the advanced oxidation treatment reaction, thereby defluorinating the compound. In the third oxidation treatment tube, the vacuum ultraviolet rays generated from the third vacuum ultraviolet irradiation device decompose hydrogen peroxide to generate OH radicals, and the OH radicals break the bonds between carbon (C) and hydrogen (H) in the second decomposition product additionally generated by substituting fluorine (F) with hydrogen (H) in the advanced reduction treatment reaction, thereby decomposing it. Vacuum ultraviolet-based perfluorinated compound decomposition water treatment device.

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