Method and device for removing perfluoroalkyl and polyfluoroalkyl substances

Abstract

The present invention relates to a method and apparatus for removing perfluorinated compounds in water that can effectively remove perfluorinated compounds by decomposing the perfluorinated compounds through a photocatalytic reaction and simultaneously removing the decomposed fluorine by insolubilizing it. The method for removing perfluorinated compounds according to the present invention is characterized by comprising the steps of: introducing a polyvalent metal into raw water containing perfluorinated compounds; performing a photocatalytic reaction on the raw water into which the polyvalent metal has been introduced to decompose the perfluorinated compounds and simultaneously induce a reaction between the fluoride ions (F-) separated from the perfluorinated compounds and the polyvalent metal to form a complex; and insolubilizing the complex.

Description

Technology Field

[0001] The present invention relates to a method and apparatus for removing perfluorinated compounds, and more specifically, to a method and apparatus for removing perfluorinated compounds in water that can effectively remove perfluorinated compounds by decomposing perfluorinated compounds through a photocatalytic reaction and simultaneously removing the decomposed fluorine by making it insoluble. Background Technology

[0002] Perfluorinated compounds (PFAS, Per- and polyfluoroalkyl substances) have excellent water and oil repellency and are widely used in the manufacture of Teflon-coated frying pans, packaging for hamburgers and snacks, shampoos and cosmetics, paints and foaming fire extinguishers, and lithium secondary battery electrolytes.

[0003] The recalcitrant nature of perfluorinated compounds is derived from the strong chemical bond (CF) between the fluorine, which has the strongest electronegativity, and carbon, and because they are resistant to biological and chemical degradation mechanisms, they do not decompose and accumulate in the human body and in nature.

[0004] Such non-biodegradable perfluorinated compounds are contained in wastewater from spent lithium batteries, etching and circuit board cleaning wastewater from semiconductor manufacturing processes, acid cleaning water from stainless steel manufacturing processes, factory wastewater from electrolytic smelting processes, and wastewater from coal-fired power plants, and these wastewaters often contain heavy metals.

[0005] Technologies for removing perfluorinated compounds include heat treatment, ozone treatment, activated carbon adsorption, reverse osmosis, ion exchange, nanofiltration, membrane treatment, and oxidation treatment, but the removal efficiency of these technologies is not high or there are limitations to continuous operation.

[0006] molecular formula C n F 2n+1 -C(=O)OH(n=8, 9, 10, 11, 12, 13) and C n F 2n+1In order to treat perfluorinated compounds of -X[X is F, Cl, Br, n=9, 10, 11, 12, 13, 14], the CF bonds must be broken and mineralized into fluoride ions. However, since there are about 4,700 types of perfluorinated compounds, it is difficult to determine the optimal conditions for breaking the CF bonds.

[0007] Meanwhile, a treatment technology for fluorine is the polyvalent metal coagulation-precipitation separation method. This is a technology that utilizes the high affinity between fluoride ions and polyvalent metals. It involves adding polyvalent metal chlorides such as aluminum sulfate, polyaluminum chloride, ferric sulfate, and ferric chloride as inorganic coagulants to contaminated water, adjusting the pH using an alkali agent to produce a colloid of aluminum hydroxide and iron hydroxide, and then separating solids and liquids by adsorbing and co-precipitating fluorine onto the produced colloid of aluminum hydroxide and iron hydroxide.

[0008] The above polyvalent metal aggregation-precipitation separation method is effective for removing fluorine, but unfortunately, it is unsuitable for treating perfluorinated compounds. This is because perfluorinated compounds are not adsorbed onto the colloids of aluminum hydroxide and iron hydroxide. This is because perfluorinated compounds in aqueous solutions form stable complex ions, and therefore, in order to remove perfluorinated compounds, it is necessary to first break the bond between fluorine and carbon.

[0009] The prior art regarding methods for removing perfluorinated compounds is as follows.

[0010] Korean Registered Patent No. 2476213 (Patent Document 1) discloses a technology for the selective removal of perfluorinated compounds in which perfluorinated compounds are adsorbed using a plurality of electrodes and granular activated carbon filled between the electrodes, and then decomposed through electrolytic oxidation. However, even if perfluorinated compounds are decomposed through electrolytic oxidation, the disadvantages include high operating costs and complex operation, such as the need to remove free fluorine through secondary treatment and regenerate the granular activated carbon if it is destroyed.

[0011] Japanese Patent Publication No. 2012-101159 (Patent Document 2) discloses a technology in which perfluorinated compounds in contaminated water are adsorbed using an adsorbent which is a polymer derived from cyclodextrin, a cyclic oligosaccharide, and then the adsorbent and perfluorinated compounds are separated by washing with polar solvents such as ethanol and acetone, thereby reusing the adsorbent and recovering the perfluorinated compounds. Although this technology simplifies the treatment process by eliminating the need for a decomposition process of perfluorinated compounds, the number of times the adsorbent can be recycled is not infinite and it must be replaced with a new adsorbent, which acts as a burden in terms of treatment costs.

[0012] Japanese Patent Publication No. 2010-119931 (Patent Document 3) discloses a method for separating and treating perfluorinated compounds in contaminated water using a porous membrane made of a spherical polyvinylidene fluoride resin, but does not provide a method for treating perfluorinated compounds in concentrated water.

[0013] Japanese Patent Publication No. 2010-131478 (Patent Document 4) discloses a method in which contaminated water is concentrated by passing it through an anion exchange treatment device, the perfluorinated compounds concentrated in the anion exchange treatment device are recovered using a desorption solvent, and the concentrated solution is rendered harmless by oxidative decomposition using a supercritical hydroxide treatment device. However, this method requires the use of chemicals necessary for the regeneration of the ion exchange resin and extreme conditions such as high temperature (over 400°C) and high pressure (30 MPa) for the production of critical water. Furthermore, even if oxidation into fluoride ions proceeds with high efficiency through critical water oxidation, the fluoride ions must be removed through coagulation and precipitation. Consequently, since operating costs are high, it is difficult to consider this an economical treatment method for perfluorinated compounds (PFAS).

[0014] Japanese Patent Publication No. 2010-22960 (Patent Document 5) discloses a method of decomposing perfluorinated compounds with nanobubbles and adsorbing the resulting decomposition product onto activated carbon, but it has the disadvantages that the decomposition rate of perfluorinated compounds is relatively low, large-scale processing is difficult, and secondary treatment of perfluorinated compounds adsorbed on activated carbon is required. Prior art literature

[0015] Korean Registered Patent No. 2476213 (Published Dec. 13, 2022) Japanese Published Patent No. JP 2012-101159 (Published May 31, 2012) Japanese Published Patent No. JP 2010-119931 (Published June 3, 2010) Japanese Published Patent No. JP 2010-131478 (Published June 17, 2010) Japanese Published Patent No. JP 2010-22960 (Published Feb. 4, 2010) The problem to be solved

[0016] The present invention was devised to solve the above-mentioned problems, and aims to provide a method and apparatus for removing perfluorinated compounds that can effectively remove perfluorinated compounds in water by decomposing perfluorinated compounds through a photocatalytic reaction and simultaneously removing the decomposed fluorine by making it insoluble. means of solving the problem

[0017] A method for removing perfluorinated compounds according to the present invention for achieving the above objective comprises the step of introducing a polyvalent metal into raw water containing perfluorinated compounds; and performing a photocatalytic reaction on the raw water into which the polyvalent metal has been introduced, thereby decomposing the perfluorinated compounds and simultaneously separating fluoride ions (F) separated from the perfluorinated compounds. - The method is characterized by comprising: a step of inducing a reaction between ) and a polyvalent metal to form a complex; and a step of insolubilizing the complex.

[0018] The photocatalytic reaction is a process in which raw water is irradiated with ultraviolet light in the presence of a photocatalyst, and fluoride ions (F) are produced through the decomposition of perfluorinated compounds. - It is a reaction in which glass of ) is produced.

[0019] The complex is a fluoride ion (F -It is a compound of ) and polyvalent metals, and is soluble.

[0020] The step of insolubilizing the complex involves adding a calcium salt to raw water containing the complex to convert the complex into insoluble CaF2.

[0021] In the step of adding a polyvalent metal to raw water containing perfluorinated compounds; the pH of the raw water is adjusted to 3.0 to 6.8 to prevent the polyvalent metal and perfluorinated compounds in the raw water from gelling.

[0022] The polyvalent metal included in the polyvalent metal or polyvalent metal salt is at least one of Al, Fe, Mg, Zn, Cu, Ti, Ni, Co, Mn, Mo, and Y. The polyvalent metal salts are Al2(SO4)3, Fe2(SO4)3, and MgSO4 4, Fe2O 3, SrAl2O 4, MoO 3, TiCl 4, It is at least one of Y2O3.

[0023] In the step of adding a polyvalent metal to raw water containing a perfluorinated compound; the polyvalent metal or polyvalent metal salt is added to the raw water such that the polyvalent metal is 0.8 to 4.0 moles per 1.0 mole of perfluorinated compound.

[0024] The photocatalyst is a metal oxide containing at least one of Ti, V, W, Zn, Fe, Ga, Cd, Bi, Sn, Sr, and Zr. As an example, one or more metal oxides selected from TiO2, V2O5, WO3, ZnO, Fe2(SO4)3, GaP, GaAs, Ga2O3, CdS, BiPO4, Bi2O3, SnO2, SrTiO3, and ZrO2 can be used as photocatalysts. Additionally, tungstic phosphate (H3PW), which is a photochemical oxidizing agent, 12 O 40 ), persulfate (S2O8 2- Any one of ) can be used as a photocatalyst.

[0025] The complex is AlF n 3-n , MgFn 3-n , FeF n 3-n and at least one of the other polyvalent metals and binding complexes.

[0026] To convert the complex into CaF2, the pH of the raw water containing the complex is adjusted to 9 to 13.

[0027] The method further includes a step of insolubilizing the complex; and a step of subsequently performing a coagulation-sedimentation process; wherein the coagulation-sedimentation process is a process of adding a coagulant to raw water containing CaF2 to flocculate CaF2 and settling the flocculed CaF2 to separate solids and liquids, and through solid-liquid separation, the raw water containing CaF2 is separated into supernatant water and sludge containing CaF2.

[0028] The perfluorinated compound removal device according to the present invention is characterized by comprising: a pretreatment tank that induces mixing of raw water containing perfluorinated compounds and a polyvalent metal; a photocatalytic reaction tank that provides a space for inducing a photocatalytic reaction of the raw water, equipped with a photocatalyst and a light source that irradiates ultraviolet rays; a fluorine insolubilization tank that insolubilizes fluorine contained in the raw water; and a coagulation-sedimentation tank that separates solids from liquids by flocculating and coagulating CaF2 contained in the raw water and precipitating the coagulated CaF2.

[0029] The raw water in the pretreatment tank is adjusted to a pH of 3.0 to 6.8.

[0030] Perfluorinated compounds are decomposed by a photocatalytic reaction in a photocatalytic reactor, producing fluoride ions (F - ) is liberated, and the liberated fluoride ions (F - ) combines with polyvalent metals to form complexes.

[0031] Raw water containing the complex is supplied to the fluoride insolubilization tank along with the introduction of calcium salt, and the complex reacts with the calcium salt to be converted into CaF2.

[0032] For the conversion of the complex into CaF2, the raw water in the fluoride insolubilization tank is adjusted to a pH of 9 to 13. Effects of the invention

[0033] The method and apparatus for removing perfluorinated compounds according to the present invention have the following effects.

[0034] More than 99% of perfluorinated compounds in water can be removed through photocatalytic reactions and fluorine insolubilization. Brief explanation of the drawing

[0035] FIG. 1 is a flowchart illustrating a method for removing perfluorinated compounds according to one embodiment of the present invention. FIG. 2 is a configuration diagram of a perfluorinated compound removal device according to one embodiment of the present invention. Specific details for implementing the invention

[0036] The present invention provides a technology for separating fluorine from perfluorinated compounds by cutting the CF bonds of perfluorinated compounds, and removing the separated fluorine through coagulation and precipitation by insolubilizing it. Through this, more than 99% of perfluorinated compounds can be removed without fluorine byproducts.

[0037] In the present invention, perfluorinated compounds (PFAS, Per- and polyfluoroalkyl substances) refer to substances in which hydrogen in the basic framework of a hydrocarbon is substituted with fluorine, and the concept includes PFOA (Perfluorooctanoic Acid) and PFOS (Perfluorooctanesulfonic Acid).

[0038] The present invention utilizes two means for the complete removal of perfluorinated compounds.

[0039] One is to decompose perfluorinated compounds through a photocatalytic reaction in the presence of a polyvalent metal, and the other is to insolubilize fluorine released from perfluorinated compounds using a calcium salt.

[0040] When ultraviolet rays are irradiated onto perfluorinated compounds in water in the presence of a photocatalyst, the CF bonds of the perfluorinated compounds are sequentially cleaved by free radicals, producing fluoride ions (F - ) is liberated. The liberated fluoride ions (F- ) combines with polyvalent metals to form soluble complexes, and the soluble complexes react with calcium salts to be converted into insoluble CaF2. Since CaF2 is insoluble, it can be easily separated through a coagulation-precipitation process, and perfluorinated compounds in water can be decomposed and removed through the above photocatalytic reaction and fluorine insolubilization. Referring to the experimental examples described below, it can be confirmed that more than 99% of perfluorinated compounds are removed through the perfluorinated compound removal method of the present invention.

[0041] Perfluorinated compound removal method

[0042] As previously mentioned, the method for removing perfluorinated compounds according to the present invention utilizes a photocatalytic reaction and fluorine insolubilization as key means. Below, a method for removing perfluorinated compounds according to an embodiment of the present invention based on a photocatalytic reaction and fluorine insolubilization will be described in detail with reference to FIG. 1.

[0043] First, a pretreatment process is performed. Specifically, a polyvalent metal or polyvalent metal salt is added to raw water containing perfluorinated compounds, and the pH of the raw water is adjusted to 3.0 to 6.8. In addition, it is preferable to add the polyvalent metal or polyvalent metal salt to the raw water such that the polyvalent metal is 0.8 to 4.0 moles per 1.0 mole of perfluorinated compounds.

[0044] Polyvalent metals introduced into raw water react with water to be converted into hydroxides; to prevent these polyvalent metal hydroxides from gelling, the pH of the raw water must be adjusted to 3.0–6.8. If polyvalent metal hydroxides gel, perfluorinated compounds (PFCs) are not uniformly dispersed within the raw water, which reduces the decomposition efficiency of PFCs during the subsequent photocatalytic reaction. Furthermore, if polyvalent metal hydroxides gel, the polyvalent metals, like PFCs, do not achieve uniform dispersion, leading to a decrease in the efficiency of complex formation between free fluoride ions and polyvalent metals, ultimately reducing the removal efficiency of PFCs. For these reasons, it is necessary to adjust the pH of the raw water to 3.0–6.8 during the pretreatment process.

[0045] Meanwhile, the polyvalent metal included in the polyvalent metal or polyvalent metal salt refers to at least one of Al, Fe, Mg, Zn, Cu, Mo, Ti, Ni, Co, Mn, Sr, and Y. The form of the polyvalent metal salt is not limited to sulfates, nitrates, etc., and when using a polyvalent metal salt in the form of a sulfate, as an example, Al2(SO4)3, Fe2(SO4)3, and MgSO4 4, Fe2O 3, MoO 3, TiCl 4, SrAl2O 4, At least one of Y2O3 can be used.

[0046] When the pretreatment process is completed, a photocatalytic reaction is performed on the raw water that has undergone the pretreatment process. A photocatalytic reaction refers to a reaction in which perfluorinated compounds are decomposed by irradiating ultraviolet rays onto raw water containing perfluorinated compounds in the presence of a photocatalyst, and the configuration of the device for implementing the photocatalytic reaction under conditions satisfying this is not particularly limited. In one embodiment, a reaction vessel equipped with a photocatalyst is prepared, raw water is allowed to pass through the reaction vessel, and the photocatalytic reaction can be induced by irradiating ultraviolet rays onto the raw water as it passes through the reaction vessel. In addition to this method, a photocatalytic reaction can also be induced by a so-called batch method in which raw water is filled into a reaction vessel equipped with a photocatalyst and ultraviolet rays are irradiated onto the raw water for a certain period of time.

[0047] Through this photocatalytic reaction, perfluorinated compounds contained in the raw water are decomposed via the reactions of Equations 1 to 4 below. Specifically, free radicals are generated by the photocatalytic reaction, and these free radicals are hydrolyzed by photochemical reactions with water molecules to form hydroxides; in this process, the CF bonds of perfluorinated compounds are sequentially broken, forming fluoride ions (F - ) is continuously released.

[0048] (Reaction Equation 1) C n F 2n+1 X Cn F 2n+1 + X

[0049] (Here, X is COO - , SO3 - , CH2CH2SO3 - It is one of the following)

[0050] (Reaction Equation 2) C n F 2n+1 + 2H2O → C n-1 F 2n-1 COO - + 3H + + 2F - + H

[0051] (Reaction Equation 3) C n-1 F 2n-1 COO - C n-1 F 2n-1 + COO -

[0052] (Reaction Equation 4) C n-1 F 2n-1 + 2H2O → C n-2 F 2n-3 COO - + 3H + + 2F - + H

[0053] Fluoride ions (F) released from perfluorinated compounds - ) combines with polyvalent metals dissolved in raw water to form complexes. That is, the aforementioned polyvalent metal and fluoride ions (F - Polyvalent metal fluorides are formed by the bonding of ). For example, AlF n 3-n , MgF n 3-n , FeF n 3-n and other polyvalent metals form a bonding complex.

[0054] In carrying out the photocatalytic reaction described above, the photocatalyst may utilize a metal oxide comprising at least one of Ti, V, W, Zn, Fe, Ga, Cd, Bi, Sn, Sr, and Zr. For example, at least one metal oxide selected from TiO2, V2O5, WO3, ZnO, Fe2(SO4)3, GaP, GaAs, Ga2O3, CdS, BiPO4, Bi2O3, SnO2, SrTiO3, and ZrO2 may be used as a photocatalyst. Additionally, tungstic phosphate (H3PW), which is a photochemical oxidizing agent, may be used. 12 O 40 ), persulfate (S2O8 2- Any one of the above may be used as a photocatalyst. Additionally, near-ultraviolet rays with a wavelength of 198 to 398 nm may be used as ultraviolet rays, and mercury lamps, xenon lamps, metal vapor lamps, krypton chloride excimer lamps, etc., may be used as light sources for irradiating ultraviolet rays. In particular, when using a mercury lamp as a near-ultraviolet light source, both low-pressure mercury lamps (0.01 to 0.1 mmHg) and high-pressure mercury lamps (0.1 to 10.0 atm) may be used, but it is preferable to use a low-pressure mercury lamp, which has excellent irradiation energy efficiency.

[0055] Once the photocatalytic reaction is complete, a fluorine insolubilization process is carried out.

[0056] Perfluorinated compounds in raw water are decomposed by a photocatalytic reaction, producing fluoride ions (F - ) is liberated, and the liberated fluoride ions (F - ) combines with polyvalent metals to form AlF n 3-n , MgF n 3-n , FeF n 3-n and a bonding complex is formed with other polyvalent metals, such as AlF n 3-n , MgF n 3-n , FeF n 3-nAnd since the complexes formed with other polyvalent metals are soluble, they cannot be easily separated from the raw water. Therefore, it is necessary to convert the soluble complexes into insoluble ones, and for this purpose, AlF n 3-n , MgF n 3-n , FeF n 3-n Calcium salts are added to raw water containing complexes with polyvalent metals and other substances. Here, inorganic calcium salts such as calcium chloride, calcium hydroxide, calcium carbonate, and calcium phosphate may be used as the calcium salt.

[0057] Upon the addition of calcium salts, the polyvalent metal of the complex is replaced by calcium (Ca), forming CaF2. That is, AlF n 3-n , MgF n 3-n , FeF n 3-n and other complexes with polyvalent metals react with calcium salts to be converted into CaF2. CaF2 is insoluble, which means it is easily separated through the coagulation-precipitation process.

[0058] In carrying out the fluoride insolubilization process, it is necessary to adjust the pH of the raw water so that the raw water becomes alkaline in order to form CaF2. For example, it is necessary to adjust the pH of the raw water to 9 to 13. During the fluoride insolubilization process and the pretreatment process described above, the pH of the raw water can be adjusted using acids such as sulfuric acid, hydrochloric acid, and nitric acid, and alkali agents such as sodium hydroxide, potassium hydroxide, and calcium hydroxide.

[0059] Once the fluoride insolubilization process is completed, a coagulation-sedimentation process is performed on the raw water containing CaF2. Specifically, a coagulant is added to the raw water containing CaF2 to floculate the CaF2, and the floculated CaF2 is precipitated.

[0060] Polymer coagulants, more specifically anionic polymer coagulants, can be used as coagulants, and the coagulant can be added at a concentration of 0.5 to 15.0 mg / L relative to the raw water. In addition, the raw water can be stirred for a certain period of time after the addition of the coagulant to promote the flocculation of CaF2. Once this flocculation is complete, the flocculated CaF2 settles by gravity, and the supernatant and the sludge containing CaF2 are separated into solid and liquid phases. Here, in addition to polymer coagulants, calcium salts of slaked lime, calcium carbonate, and calcium chloride, aluminum salts of aluminum sulfate, and magnesium salts of magnesium sulfate may also be used as coagulants.

[0061] After the completion of the coagulation-sedimentation process, the supernatant is discharged as treated water, and the sludge containing CaF2 is withdrawn and treated separately. For example, the sludge containing CaF2 can be withdrawn and reused or disposed of.

[0062] Above, a method for removing perfluorinated compounds according to one embodiment of the present invention has been described.

[0063] Perfluorinated compound removal device

[0064] As described above, the method for removing perfluorinated compounds according to the present invention is based on photocatalytic reaction and fluorine insolubilization, and under conditions satisfying this, the configuration of the device is not particularly limited. A perfluorinated compound removal device according to one embodiment of the present invention is described as follows.

[0065] Referring to FIG. 2, a perfluorinated compound removal device according to one embodiment of the present invention comprises a pretreatment tank (110), a photocatalytic reaction tank (120), a fluorine insolubilization tank (130), and a coagulation-sedimentation tank (140).

[0066] The pretreatment tank (110) induces uniform dispersion of polyvalent metals and perfluorinated compounds. Raw water containing perfluorinated compounds is supplied into the pretreatment tank (110), and a polyvalent metal or a polyvalent metal salt is introduced into the raw water containing perfluorinated compounds. The polyvalent metal is a fluoride ion (F) released during a subsequent photocatalytic reaction. -It plays a role in forming a complex by reacting with ).

[0067] In order to ensure uniform dispersion of polyvalent metals and perfluorinated compounds, the raw water of the pretreatment tank (110) must be adjusted to a pH of 3.0 to 6.8. If the pH of the raw water deviates from the above range, the polyvalent metal gels, and not only the perfluorinated compounds but also the polyvalent metals are not uniformly dispersed. If the perfluorinated compounds are not uniformly dispersed in the raw water due to gelation, the decomposition efficiency of the perfluorinated compounds is reduced during the subsequent photocatalytic reaction. Furthermore, if the polyvalent metal hydroxide gels, the polyvalent metals also do not achieve uniform dispersion, just like the perfluorinated compounds, and the efficiency of complex formation between the freed fluoride ions and the polyvalent metals decreases, ultimately reducing the removal efficiency of the perfluorinated compounds.

[0068] The photocatalytic reaction tank (120) is equipped with a photocatalyst and a light source that irradiates ultraviolet rays, and provides a space for inducing a photocatalytic reaction of raw water. Raw water that has passed through the pretreatment tank (110) passes through the photocatalytic reaction tank (120) equipped with a photocatalyst, and ultraviolet rays are irradiated onto the raw water as it passes through the photocatalytic reaction tank (120).

[0069] In the process of raw water passing through a photocatalytic reaction tank (120) where ultraviolet rays are irradiated, perfluorinated compounds contained in the raw water are decomposed by a photocatalytic reaction such as reaction formulas 1 to 4 above, and fluoride ions (F) are produced by the decomposition of perfluorinated compounds. - ) is liberated. The liberated fluoride ions (F - ) combines with polyvalent metals contained in the raw water to form AlF n 3-n , MgF n 3-n , FeF n 3-n and forms a complex with other polyvalent metals. That is, as it passes through the photocatalytic reactor (120), the perfluorinated compounds in the raw water become AlF n 3-n , MgF n 3-n , FeF n 3-nand is converted into a binding complex with other polyvalent metals.

[0070] The fluoride insolubilization tank (130) serves to insolubilize the fluoride contained in the raw water. Raw water that has passed through the photocatalytic reaction tank (120) is supplied to the fluoride insolubilization tank (130), and calcium salt is introduced into the raw water of the fluoride insolubilization tank (130). AlF contained in the raw water in the fluoride insolubilization tank (130) n 3-n , MgF n 3-n , FeF n 3-n The soluble complex combined with other polyvalent metals reacts with the calcium salt to be converted into insoluble CaF2. To convert the complex into CaF2, the raw water of the fluoride insolubilization tank (130) needs to be adjusted to a pH of 9 to 13.

[0071] The coagulation-sedimentation tank (140) receives raw water from the fluoride insolubilization tank (130), flocculates the CaF2 contained in the raw water to coagulate it, and simultaneously settles the flocculated CaF2, thereby separating the raw water into solid and liquid phases. The coagulation process of flocculating CaF2 and the sedimentation process of flocculated CaF2 can proceed sequentially within the coagulation-sedimentation tank (140), and an agitator may be provided within the coagulation-sedimentation tank (140) to promote the flocculation of CaF2. Through solid and liquid separation within the coagulation-sedimentation tank (140), the raw water is separated into supernatant water and sludge containing CaF2; the supernatant water is discharged as treated water, and the sludge containing CaF2 is withdrawn and disposed of.

[0072] The above describes a method and apparatus for removing perfluorinated compounds according to one embodiment of the present invention. Below, the present invention will be described in more detail through experimental examples.

[0073] Experimental Example 1: Examples 1–3 and Comparative Examples 1–3

[0074] In conducting the experiments of Experimental Examples 1 to 6 (see Tables 1 to 6), the common experimental conditions are as follows.

[0075] A 20L mixed solution of 100mg / L PFOA (Perfluorooctanoic Acid) and 100mg / L PFOS (Perfluorooctanesulfonic Acid) was prepared and used as contaminated water containing perfluorinated compounds.

[0076] 0.5 L of contaminated water containing perfluorinated compounds was collected in a polyethylene beaker, and polyvalent metal salts (Al2(SO4)3, Fe2(SO4)3, MgSO4) were added at concentrations shown in Tables 1 to 6 below. Then, while stirring, the pH was adjusted to 6.5 using H2SO4 and NaOH. This contaminated water was passed through a photocatalytic reactor filled with a photocatalyst at a flow rate of 20 to 60 ml / min. A near-ultraviolet lamp (10W low-pressure mercury lamp / UL1-1DQ experimental T-USHIO) was installed inside the photocatalytic reactor, and near-ultraviolet light was irradiated as the contaminated water passed through.

[0077] Ca(OH)2 was added to the contaminated water passing through the photocatalytic reactor, and NaOH and the like were added to adjust the pH to 11.0. Subsequently, a flocculation-sedimentation treatment was performed by adding an organic polymer coagulant and flocculating the water while stirring for 20 minutes. Following this, solid-liquid separation was carried out, and the residual concentrations of PFOA and PFOS in the supernatant were quantified using a Prominence LC-20ADXR / LCMS8030plus analyzer (LC / MS / MS, manufactured by Shimadzu Corporation). The column used was a Wakopak® UltraC18-3, 2.0 mm × 150 mm, and the eluents were 10 mM CH3COONH4in H2O and CH3CN, and the internal standard reagent was 13 C-PFOA· 13 A mixture of C-PFOS (PFOA 20 mg / L, PFOS 20 mg / L) was used. In addition, the residual fluoride concentration in the supernatant was measured using an IC (ion chromatograph) analyzer (DIONEX DX-500 type manufactured by Dionex).

[0078] Meanwhile, the contaminated water was maintained at 18°C ​​to 25°C throughout the aforementioned treatment process.

[0079] Above, the common experimental conditions of Tables 1 to 6 were described.

[0080] The specific experimental conditions for Examples 1 to 3 and Comparative Examples 1 to 3 are as follows (see Table 1).

[0081] In Examples 1 to 3 and Comparative Examples 1 to 3, Al2(SO4)3 was used as the polyvalent metal salt, and Al2(SO4)3 was added such that the aluminum ion content was 0.8 to 4.0 moles for every 1.0 mole of perfluorinated compound. In the case of Examples 1 to 3, near-ultraviolet rays were irradiated as the contaminated water passed through a photocatalytic reactor filled with TiO2, whereas in the case of Comparative Examples 1 to 3, near-ultraviolet rays were not irradiated as the contaminated water passed through the photocatalytic reactor.

[0082] division Pretreatment process Photocatalytic reaction (TiO2) treated water Amount of polyvalent metal salt added (mg / L) [Al2(SO4)3] pH Flow rate (ml / min) UV irradiation 주1) PFOA 주1) PFOS 주2) F(fluorine) Residual concentration (mg / L) Residual concentration (mg / L) Residual concentration (mg / L) Example 1 Al 1.0 6.5(6.4) 20 you 27.0×10 -6 26.5×10 -6 13.5 Comparative Example 1 Al 1.0 6.5(6.6) 20 radish 75.8 73.1 - Example 2 Al 5.0 6.5(6.4) 40 you 28.5×10 -6 27.5×10 -6 12.5 Comparative Example 2 Al 5.0 6.5(6.5) 40 radish 84.7 80.4 - Example 3 Al 10.0 6.5(6.6) 60 you 615.5×10 -6 533.0×10 -6 14.0 Comparative Example 3 Al 10.0 6.5(6.4) 60 radish 91.1 87.5 -

[0083] Note 1) LC-20ADXR / LCMS8030plus-LC / MS / MS (Made by Shimadzu Corporation), PFOA LOQ: 0.5ng / L, PFOS LOQ: 0.5ng / L

[0084] Note 2) IC-DIONEX DX-500 type (manufactured by Dionex), F- LOQ: <1.5 mg / L

[0085] As shown in Table 1, the experimental results indicate that the residual concentration of PFOA in Example 1 was 27.0 ng / L and the residual concentration of PFOS was 26.5 ng / L, with the sum of the residual concentrations of PFOA and PFOS being 53.5 ng / L. These results indicate that more than 99% of PFOA and PFOS were removed from the contaminated water (including Examples 2 and 3). However, in the case of Examples 2 and 3, where the flow rate was increased, the residence time in the photocatalytic reactor decreased, showing a tendency for the residual concentrations of PFOA and PFOS to increase.

[0086] When comparing the PFOA and PFOS removal efficiency of Examples 1 to 3 with Comparative Examples 1 to 3, it can be confirmed that the PFOA and PFOS removal efficiency is more than one million times better, even when compared to Comparative Example 1 (PFOA residual concentration 75.8 mg / L, PFOS residual concentration 73.1 mg / L), which is the best among the comparative examples.

[0087] Experimental Example 2: Examples 4–6 and Comparative Examples 4–6

[0088] As shown in Table 2, Fe2(SO4)3 was used as the polyvalent metal salt in Examples 4 to 6 and Comparative Examples 4 to 6, and Fe2(SO4)3 was added such that the iron ion content was 0.8 to 4.0 moles for every 1.0 mole of perfluorinated compound. In the case of Examples 4 to 6, near-ultraviolet rays were irradiated as the contaminated water passed through a photocatalytic reactor filled with TiO2, whereas in the case of Comparative Examples 4 to 6, near-ultraviolet rays were not irradiated as the contaminated water passed through the photocatalytic reactor.

[0089] division Pretreatment process Photocatalytic reaction (TiO2) treated water Amount of polyvalent metal salt added (mg / L) [Fe2(SO4)3] pH Flow rate (ml / min) UV irradiation 주1) PFOA 주1) PFOS 주2) F(fluorine) Residual concentration (mg / L) Residual concentration (mg / L) Residual concentration (mg / L) Example 4 Fe 1.0 6.5(6.6) 20 you 28.5×10 -6 27.5×10 -6 14.5 Comparative Example 4 Fe 1.0 6.5(6.5) 20 radish 89.1 88.4 - Example 5 Fe 5.0 6.5(6.6) 40 you 30.5×10 -6 28.5×10 -6 13.5 Comparative Example 5 Fe 5.0 6.5(6.4) 40 radish 92.9 89.4 - Example 6 Fe 10.0 6.5(6.6) 60 you 720.0×10 -6 618.5×10 -6 15.0 Comparative Example 6 Fe 10.0 6.5(6.5) 60 radish 97.3 95.1 -

[0090] Note 1) LC-20ADXR / LCMS8030plus-LC / MS / MS (Made by Shimadzu Corporation), PFOA LOQ: 0.5ng / L, PFOS LOQ: 0.5ng / L

[0091] Note 2) IC-DIONEX DX-500 type (manufactured by Dionex), F- LOQ: <1.5 mg / L

[0092] Referring to Table 2 for the experimental results, the residual concentration of PFOA in Example 4 was 28.5 ng / L and the residual concentration of PFOS was 27.5 ng / L, and the sum of the residual concentrations of PFOA and PFOS was 56.0 ng / L. These results indicate that more than 99% of PFOA and PFOS were removed from the contaminated water (including Examples 5 and 6). However, in the case of Examples 5 and 6, where the flow rate was increased, the residence time in the photocatalytic reactor decreased, showing a tendency for the residual concentrations of PFOA and PFOS to increase.

[0093] When comparing the PFOA and PFOS removal efficiency of Examples 4 to 6 with Comparative Examples 4 to 6, it can be confirmed that the PFOA and PFOS removal efficiency is more than one million times better, even when compared to Comparative Example 4 (PFOA residual concentration 89.1 mg / L, PFOS residual concentration 88.4 mg / L), which is the best among the comparative examples.

[0094] Experimental Example 3: Examples 7–9 and Comparative Examples 7–9

[0095] As shown in Table 3, MgSO4 was used as the polyvalent metal salt in Examples 7 to 9 and Comparative Examples 7 to 9, and MgSO4 was added such that the magnesium ion content was 0.8 to 4.0 moles for every 1.0 mole of perfluorinated compound. In the case of Examples 7 to 9, near-ultraviolet rays were irradiated as the contaminated water passed through a photocatalytic reactor filled with TiO2, whereas in the case of Comparative Examples 7 to 9, near-ultraviolet rays were not irradiated as the contaminated water passed through the photocatalytic reactor.

[0096] division Pretreatment process Photocatalytic reaction (TiO2) treated water Amount of polyvalent metal salt added (mg / L) [MgSO4] pH Flow rate (ml / min) UV irradiation 주1) PFOA 주1) PFOS 주2) F(fluorine) Residual concentration (mg / L) Residual concentration (mg / L) Residual concentration (mg / L) Example 7 Mg 1.0 6.5(6.5) 20 you 22.5×10 -6 21.5×10 -6 12.5 Comparative Example 7 Mg 1.0 6.5(6.4) 20 radish 73.7 71.5 - Example 8 Mg 5.0 6.5(6.3) 40 you 23.0×10 -6 22.0×10 -6 14.0 Comparative Example 8 Mg 5.0 6.5(6.6) 40 radish 83.7 82.4 - Example 9 Mg 10.0 6.5(6.3) 60 you 550.0×10 -6 519.0×10 -6 13.5 Comparative Example 9 Mg 10.0 6.5(6.5) 60 radish 89.2 87.5 -

[0097] Note 1) LC-20ADXR / LCMS8030plus-LC / MS / MS (Made by Shimadzu Corporation), PFOA LOQ: 0.5ng / L, PFOS LOQ: 0.5ng / L

[0098] Note 2) IC-DIONEX DX-500 type (manufactured by Dionex), F- LOQ: <1.5 mg / L

[0099] Referring to Table 3 for the experimental results, the residual concentration of PFOA in Example 7 was 22.5 ng / L and the residual concentration of PFOS was 21.5 ng / L, and the sum of the residual concentrations of PFOA and PFOS was 44.0 ng / L. These results indicate that more than 99% of PFOA and PFOS were removed from the contaminated water (including Examples 8 and 9). However, in the case of Examples 8 and 9, where the flow rate was increased, the residence time in the photocatalytic reactor decreased, showing a tendency for the residual concentrations of PFOA and PFOS to increase.

[0100] When comparing the PFOA and PFOS removal efficiency of Examples 7 to 9 with Comparative Examples 7 to 9, it can be confirmed that the PFOA and PFOS removal efficiency is more than one million times better, even when compared to Comparative Example 7 (PFOA residual concentration 73.7 mg / L, PFOS residual concentration 71.5 mg / L), which is the best among the comparative examples.

[0101] Experimental Example 4: Examples 10–12 and Comparative Examples 10–12

[0102] As shown in Table 4, Al2(SO4)3 was used as the polyvalent metal salt in Examples 10 to 12 and Comparative Examples 10 to 12, and Al2(SO4)3 was added such that the aluminum ion content was 0.8 to 4.0 moles for every 1.0 mole of perfluorinated compound. In the case of Examples 10 to 12, near-ultraviolet rays were irradiated as the contaminated water passed through a photocatalytic reactor filled with V2O5, whereas in the case of Comparative Examples 10 to 12, near-ultraviolet rays were not irradiated as the contaminated water passed through the photocatalytic reactor.

[0103] division Pretreatment process Photocatalytic reaction (V2O5) treated water Amount of polyvalent metal salt added (mg / L) [Al2(SO4)3] pH Flow rate (ml / min) UV irradiation 주1) PFOA 주1) PFOS 주2) F(fluorine) Residual concentration (mg / L) Residual concentration (mg / L) Residual concentration (mg / L) Example 10 Al 1.0 6.5(6.3) 20 you 27.0×10 -6 26.5×10 -6 11.5 Comparative Example 10 Al 1.0 6.5(6.4) 20 radish 85.1 84.0 - Example 11 Al 5.0 6.5(6.6) 40 you 28.0×10 -6 27.5×10 -6 12.5 Comparative Example 11 Al 5.0 6.5(6.6) 40 radish 86.7 85.4 - Example 12 Al 10.0 6.5(6.3) 60 you 626.0×10 -6 605.5×10 -6 12.0 Comparative Example 12 Al 10.0 6.5(6.6) 60 radish 94.1 91.5 -

[0104] Note 1) LC-20ADXR / LCMS8030plus-LC / MS / MS (Made by Shimadzu Corporation), PFOA LOQ: 0.5ng / L, PFOS LOQ: 0.5ng / L

[0105] Note 2) IC-DIONEX DX-500 type (manufactured by Dionex), F- LOQ: <1.5 mg / L

[0106] Referring to Table 4 for the experimental results, the residual concentration of PFOA in Example 10 was 27.0 ng / L and the residual concentration of PFOS was 26.5 ng / L, and the sum of the residual concentrations of PFOA and PFOS was 53.5 ng / L. These results indicate that 99.9% of PFOA and PFOS were removed from the contaminated water (including Examples 11 and 12). However, in the case of Examples 11 and 12, where the flow rate was increased, the residence time in the photocatalytic reactor decreased, showing a tendency for the residual concentrations of PFOA and PFOS to increase.

[0107] When comparing the PFOA and PFOS removal efficiency of Examples 10 to 12 with Comparative Examples 10 to 12, it can be confirmed that the PFOA and PFOS removal efficiency is more than one million times better, even when compared to Comparative Example 10 (PFOA residual concentration 85.1 mg / L, PFOS residual concentration 84.0 mg / L), which is the best among the comparative examples.

[0108] Experimental Example 5: Examples 13–15 and Comparative Examples 13–15

[0109] As shown in Table 5, Fe2(SO4)3 was used as the polyvalent metal salt in Examples 13 to 15 and Comparative Examples 13 to 15, and Fe2(SO4)3 was added such that the iron ion content was 0.8 to 4.0 moles for every 1.0 mole of perfluorinated compound. In the case of Examples 13 to 15, near-ultraviolet rays were irradiated as the contaminated water passed through a photocatalytic reactor filled with V2O5, whereas in the case of Comparative Examples 13 to 15, near-ultraviolet rays were not irradiated as the contaminated water passed through the photocatalytic reactor.

[0110] division Pretreatment process Photocatalytic reaction (V2O5) treated water Amount of polyvalent metal salt added (mg / L) [Fe2(SO4)3] pH Flow rate (ml / min) UV irradiation 주1) PFOA 주1) PFOS 주2) F(fluorine) Residual concentration (mg / L) Residual concentration (mg / L) Residual concentration (mg / L) Example 13 Fe 1.0 6.5(6.6) 20 you 27.5×10 -6 26.5×10 -6 13.5 Comparative Example 13 Fe 1.0 6.5(6.4) 20 radish 86.1 85.5 - Example 14 Fe 5.0 6.5(6.5) 40 you 29.0×10 -6 28.5×10 -6 13.5 Comparative Example 14 Fe 5.0 6.5(6.3) 40 radish 88.8 87.9 - Example 15 Fe 10.0 6.5(6.6) 60 you 653.0×10 -6 605.5×10 -6 14.0 Comparative Example 15 Fe 10.0 6.5(6.6) 60 radish 97.0 93.4 -

[0111] Note 1) LC-20ADXR / LCMS8030plus-LC / MS / MS (Made by Shimadzu Corporation), PFOA LOQ: 0.5ng / L, PFOS LOQ: 0.5ng / L

[0112] Note 2) IC-DIONEX DX-500 type (manufactured by Dionex), F- LOQ: <1.5 mg / L

[0113] Referring to Table 5 for the experimental results, the residual concentration of PFOA in Example 13 was 27.5 ng / L and the residual concentration of PFOS was 26.5 ng / L, and the sum of the residual concentrations of PFOA and PFOS was 54.0 ng / L. These results indicate that more than 99% of PFOA and PFOS were removed from the contaminated water (including Examples 14 and 15). However, in the case of Examples 14 and 15, where the flow rate was increased, the residence time in the photocatalytic reactor decreased, showing a tendency for the residual concentrations of PFOA and PFOS to increase.

[0114] When comparing the PFOA and PFOS removal efficiency of Examples 13 to 15 with Comparative Examples 13 to 15, it can be confirmed that the PFOA and PFOS removal efficiency is more than one million times better, even when compared to Comparative Example 13 (PFOA residual concentration 86.1 mg / L, PFOS residual concentration 85.5 mg / L), which is the best among the comparative examples.

[0115] Experimental Example 6: Examples 16–18 and Comparative Examples 16–18

[0116] As shown in Table 6, MgSO4 was used as the polyvalent metal salt in Examples 16 to 18 and Comparative Examples 16 to 18, and MgSO4 was added such that the magnesium ion content was 0.8 to 4.0 moles for every 1.0 mole of perfluorinated compound. In the case of Examples 16 to 18, near-ultraviolet rays were irradiated as the contaminated water passed through a photocatalytic reactor filled with V2O5, whereas in the case of Comparative Examples 16 to 18, near-ultraviolet rays were not irradiated as the contaminated water passed through the photocatalytic reactor.

[0117] division Pretreatment process Photocatalytic reaction (V2O5) treated water Amount of polyvalent metal salt added (mg / L) [MgSO4] pH Flow rate (ml / min) UV irradiation 주1) PFOA 주1) PFOS 주2) F(fluorine) Residual concentration (mg / L) Residual concentration (mg / L) Residual concentration (mg / L) Example 16 Mg 1.0 6.5(6.5) 20 you 23.5×10 -6 22.5×10 -6 13.0 Comparative Example 16 Mg 1.0 6.5(6.5) 20 radish 84.7 83.4 - Example 17 Mg 5.0 6.5(6.3) 40 you 25.5×10 -6 24.0×10 -6 13.5 Comparative Example 17 Mg 5.0 6.5(6.6) 40 radish 86.8 85.9 - Example 18 Mg 10.0 6.5(6.5) 60 you 671.0×10 -6 620.5×10 -6 12.5 Comparative Example 18 Mg 10.0 6.5(6.6) 60 radish 92.1 90.5 -

[0118] Note 1) LC-20ADXR / LCMS8030plus-LC / MS / MS (Made by Shimadzu Corporation), PFOA LOQ: 0.5ng / L, PFOS LOQ: 0.5ng / L

[0119] Note 2) IC-DIONEX DX-500 type (manufactured by Dionex), F- LOQ: <1.5 mg / L

[0120] Referring to Table 6 for the experimental results, the residual concentration of PFOA in Example 16 was 23.5 ng / L and the residual concentration of PFOS was 22.5 ng / L, and the sum of the residual concentrations of PFOA and PFOS was 46.0 ng / L. These results indicate that more than 99% of PFOA and PFOS were removed from the contaminated water (including Examples 17 and 18). However, in the case of Examples 17 and 18, where the flow rate was increased, the residence time in the photocatalytic reactor decreased, showing a tendency for the residual concentrations of PFOA and PFOS to increase.

[0121] When comparing the PFOA and PFOS removal efficiency of Examples 16 to 18 with Comparative Examples 16 to 18, it can be confirmed that the PFOA and PFOS removal efficiency is more than one million times better, even when compared to Comparative Example 16 (PFOA residual concentration 84.7 mg / L, PFOS residual concentration 83.4 mg / L), which is the best among the comparative examples.

[0122] Through Experimental Examples 1 to 6 above, it can be seen that the method for removing perfluorinated compounds according to the present invention is highly effective in decomposing and removing perfluorinated compounds. Summarizing the experimental results of Experimental Examples 1 to 6, as can be seen from Examples 1 to 18, the removal rates of perfluorinated compounds PFOA and PFPS are each 99% or higher, and the residual fluoride concentration is only 15.0 mg / L or less. On the other hand, in Comparative Examples 1 to 18, where a photocatalytic reaction was not applied, the removal rates of PFOA and PFPS are only 2.7–26.3% and 4.9–28.5%, respectively, confirming that the perfluorinated compound removal efficiency is significantly lower compared to the present invention. Explanation of the symbols

[0123] 110: Pretreatment tank 120: Photocatalytic reactor 130: Fluoride Insolubilization Tank 140: Coagulation-Sedimentation Tank

Claims

Claim 1 A step of introducing a polyvalent metal into raw water containing perfluorinated compounds; performing a photocatalytic reaction on the raw water to which the polyvalent metal has been introduced, thereby decomposing the perfluorinated compounds and simultaneously producing fluoride ions (F) separated from the perfluorinated compounds. - A method for removing perfluorinated compounds, characterized by comprising: a step of inducing a reaction between ) and a polyvalent metal to form a complex; and a step of insolubilizing the complex. Claim 2 In claim 1, the photocatalytic reaction comprises fluoride ions (F) produced by the decomposition of perfluorinated compounds through the irradiation of raw water with ultraviolet rays in the presence of a photocatalyst. - A method for removing perfluorinated compounds characterized by a reaction in which glass of ) is generated. Claim 3 In claim 1, the complex is a fluoride ion (F - A method for removing perfluorinated compounds characterized by being a compound of ) and a polyvalent metal and being soluble. Claim 4 A method for removing perfluorinated compounds according to claim 3, wherein the step of insolubilizing the complex is characterized by adding a calcium salt to raw water containing the complex to convert the complex into insoluble CaF2. Claim 5 A method for removing perfluorinated compounds according to claim 1, characterized in that, in the step of adding a polyvalent metal to raw water containing perfluorinated compounds, the pH of the raw water is adjusted to 3.0 to 6.8 to prevent the polyvalent metal and perfluorinated compounds in the raw water from gelling. Claim 6 A method for removing perfluorinated compounds according to claim 1, characterized in that the polyvalent metal included in the polyvalent metal or polyvalent metal salt is at least one of Al, Fe, Mg, Zn, Cu, Mo, Ti, Ni, Co, Mn, Sr, and Y. Claim 7 In claim 6, the polyvalent metal salts are Al2(SO4)3, Fe2(SO4)3, and MgSO4 4, Fe2O 3, SrAl2O 4, MoO 3, TiCl 4, A method for removing perfluorinated compounds characterized by being at least one of Y2O3. Claim 8 A method for removing perfluorinated compounds according to claim 1, wherein, in the step of adding a polyvalent metal to raw water containing perfluorinated compounds, the polyvalent metal or polyvalent metal salt is added to the raw water such that the polyvalent metal is 0.8 to 4.0 moles per 1.0 mole of perfluorinated compound. Claim 9 A method for removing perfluorinated compounds according to claim 2, wherein the photocatalyst is a metal oxide comprising at least one of Ti, V, W, Zn, Fe, Ga, Cd, Bi, Sn, Sr, and Zr. Claim 10 In claim 2, TiO2, V2O5, WO3, ZnO, Fe2(SO4)3, GaP, GaAs, Ga2O3, CdS, BiPO4, Bi2O3, SnO2, SrTiO3, ZrO2 and, Tungstic acid phosphate (H3PW), a photochemical oxidizing agent 12 O 40 ), persulfate (S2O8 2- A method for removing perfluorinated compounds characterized by using one or more of the following as a photocatalyst. Claim 11 In claim 3, the complex is AlF n 3-n , MgF n 3-n , FeF n 3-n A method for removing perfluorinated compounds characterized by having at least one of a combination complex with other polyvalent metals. Claim 12 A method for removing perfluorinated compounds according to claim 4, characterized in that the pH of raw water containing the complex is adjusted to 9 to 13 for the conversion of the complex to CaF2. Claim 13 A method for removing perfluorinated compounds according to claim 1, further comprising: a step of insolubilizing the complex; and a step of subsequently performing a coagulation-sedimentation process; wherein the coagulation-sedimentation process is a process of adding a coagulant to raw water containing CaF2 to floculate CaF2 and precipitating the floculated CaF2 to separate solids and liquids, and wherein the raw water containing CaF2 is separated into supernatant water and sludge containing CaF2 by solid-liquid separation. Claim 14 A perfluorinated compound removal device characterized by comprising: a pretreatment tank that induces mixing of raw water containing perfluorinated compounds and a polyvalent metal; a photocatalytic reaction tank that provides a space for inducing a photocatalytic reaction of the raw water, equipped with a photocatalyst and a light source that irradiates ultraviolet rays; a fluorine insolubilization tank that insolubilizes fluorine contained in the raw water; and a coagulation-sedimentation tank that separates solids from liquids by flocculating and coagulating CaF2 contained in the raw water and precipitating the coagulated CaF2. Claim 15 A perfluorinated compound removal device according to claim 14, characterized in that the raw water in the pretreatment tank is adjusted to a pH of 3.0 to 6.

8. Claim 16 In claim 14, perfluorinated compounds are decomposed by a photocatalytic reaction in a photocatalytic reactor to form fluoride ions (F - ) is liberated, and the liberated fluoride ions (F - A perfluorinated compound removal device characterized by forming a complex by combining with a polyvalent metal. Claim 17 A perfluorinated compound removal device according to claim 14, characterized in that raw water containing a complex is supplied to a fluoride insolubilization tank along with the introduction of a calcium salt, and the complex reacts with the calcium salt to be converted into CaF2. Claim 18 A perfluorinated compound removal device according to claim 17, characterized in that the raw water in the fluoride insolubilization tank is adjusted to a pH of 9 to 13 for the conversion of the complex into CaF2.

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