JP2012005996A - Method for treating organic compound by fenton reaction - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a treatment method for an organic compound capable of efficiently and continuously decomposing the organic compound.SOLUTION: In the treatment method for the organic compound, hydrogen peroxide and a compound (A) capable of generating metal ions (I) to cause Fenton reaction are added to soil water including the organic compound, and oxidation decomposition of the organic compound is performed by radicals generated by the Fenton reaction. The treatment method for the organic compound includes a step of adding, to the soil water, a compound (B) capable of generating anion which is different from counter anion combined when metal ions (I) generated by the reaction between the hydrogen peroxide and the metal ions (I) form metal salt and precipitate and of preventing precipitation of a compound formed from the metal ions (I) and/or the metal ions (I) by making one and 1.5 times equivalent amount or more of the different anion with respect to the metal ions (I) in the compound (A) added to the soil water present in the soil water.

Description

  The present invention relates to a method for treating an organic compound by a Fenton reaction. More specifically, the present invention adds hydrogen peroxide and a compound capable of generating metal ions for causing a Fenton reaction to wastewater containing an organic compound, and oxidizes the organic compound by radicals generated by the Fenton reaction. The present invention relates to a method for treating an organic compound that decomposes.

  In response to growing interest in water resource utilization in recent years, the treatment of organic compounds contained in domestic wastewater, industrial wastewater, livestock wastewater, and the like has increased in importance [Patent Document 1, Non-Patent Documents 1 and 2, etc.]. For example, organic compounds such as atrazine and 1,4-dioxane are generally used as herbicides and detergents, but such persistent organic compounds are conventionally used for biological treatment, ozone oxidation, activated carbon adsorption, and the like. It has been pointed out that it is difficult to disassemble and the like, causing water pollution (Patent Document 2, Non-Patent Document 3, etc.).

  On the other hand, the Fenton reaction, which generates highly reactive radicals using hydrogen peroxide and a metal ion catalyst as raw materials, has attracted attention as a method for oxidatively decomposing refractory organic compounds because the radicals have strong oxidizing power. . This method has many advantages over conventional methods, such as being feasible at low temperatures and with simple equipment, and not releasing harmful gases such as NOx and SOx during the decomposition process [Non-Patent Document 4]. ~ 8 etc.]. In addition to the aforementioned atrazine and 1,4-dioxane, various kinds of organic compounds such as various alcohols, aldehydes, aromatic compounds, amines, and ketones can be oxidatively decomposed [Non-Patent Document 9]. Such].

  However, the oxidative decomposition method using the Fenton reaction has been regarded as a problem that metal ions added as a catalyst for generating radicals from hydrogen peroxide precipitate as metal salts, resulting in an increase in the amount of waste. [Non-Patent Documents 10, 11, etc.]. For example, Patent Documents 3 and 4 describe that waste is treated by a neutralization tank and a precipitation tank for precipitating and removing metal ions that are catalysts for the Fenton reaction. As described above, in the technology related to the oxidative decomposition method using the Fenton reaction, spots are applied to the treatment after the oxidative decomposition, such as a method for precipitating and removing metal ions, which are catalysts for the Fenton reaction, and a method for reusing the precipitated catalyst. ing.

JP 2008-229450 A JP 2005-58854 A JP 2003-300083 A JP-A-6-182362

D. F. Bishop, G.M. Stern, M.M. Fleischman and L. S. Marshall, Hydrogen peroxide catalytic oxidation of refractory organics in uniaxial wastewaters, Ind. Eng. Process Des. Dev. 1968, 7 (1), 110-117. M.M. Murganandham and M.M. Swamithan, Demolition of Reactive Orange 4 by Fenton and photo-Fenton oxidation technology, Dies Pigm. , 2004, 63, 315-321 A. Ventura, G.M. Jacquet, A.J. Bermond and V.M. Camel, Electrochemical generation of the Fenton's reagent: application to atrazine degradation, Water Res. , 2002, 36, 3517-3522 X. Jian, T.W. Wu and G. Yun, A study of wet catalytic oxidation of radioactive stress exchange exchange by hydrogen peroxide, Nucl. Safety, 1996, 37 (2), 149-157 J. et al. P. Wilks and N.W. S. Holt, Wet oxidation of mixed organic and organic radioactive sludge wastes from water reactor, Waste Management. , 1990, 10, 197-203. M.M. Vilve, A.M. Hirvonen and M.M. Sillanpaa, Effects of reaction conditions on nuclear groundwater treatment in Fenton process, J. Am. Hazard. Mater. , 2009, 164, 1468-1473. Takeshi Izumi, Masahiro Sugawara, Takashi Otsu, Hirofumi Inagawa, Masayuki Arai, Development of Radioactive Used Ion Exchange Resin Treatment Method, Ebara Times, 2008, 218, 29-34 C. Srinivas, G.M. Normal and P.M. K. Wattal, Management of stress organic-exchange resins by photochemical oxidation, Proc. Waste Management '03 Conf. , Feb. 23-27, 2003 R. J. et al. Bigda, Consider Fenton's chemistry for wastewater treatment, Chem. Eng. Prog. , 1995 Dec, 62-66. G. -M. Cao, M.C. Sheng, W.H. -F. Niu, Y .; -L. Fei and D. Li, Generation and reuse of iron cat for for Fenton-like reactions, J. Am. Hazard. Mater. , 2009, 172, 1446-1449. Kanichi Hayashi, Yoichi Nakajima, Kiyohisa Ota, Development of decomposition method of organic compounds in the environment using iron oxide, Report of Osaka Prefectural Institute of Advanced Industrial Science and Technology, 2007, 21, 79-83

  An object of the present invention is to provide a method for treating an organic compound that prevents the precipitation of the metal ion catalyst used in the Fenton reaction and efficiently and continuously decomposes the organic compound.

In the method for treating an organic compound of the present invention, hydrogen peroxide and a compound (A) capable of generating a metal ion (I ₁ ) for causing a Fenton reaction are added to wastewater containing the organic compound, and the Fenton reaction is performed. A method for treating an organic compound in which the organic compound is oxidatively decomposed by a generated radical, wherein the metal ion (I ₂ ) generated by the reaction between the hydrogen peroxide and the metal ion (I ₁ ) is converted into a metal salt in the waste water. A compound (B) capable of generating an anion different from the counter anion that forms a compound upon precipitation is formed, and the metal ion (I ₁ ) added to the waste water can be generated in the waste water. the metal ion in the compound (a) (I _1), be present in the anion amount of more than 1.5 equivalents of the dissimilar from the metal ion (I ₁₎ and / or metal ion (I ₂₎ Characterized in that it comprises a step of preventing the precipitation of the made compound.

  According to the method for treating an organic compound of the present invention, precipitation of the metal ion catalyst can be suppressed very effectively. Therefore, the amount of metal ion catalyst used as a Fenton reagent can be reduced, and the amount of precipitates such as sludge often generated in the decomposition treatment of organic compounds by the Fenton reaction can be dramatically reduced.

  In addition, the present invention is sufficient for oxidative decomposition treatment of various types of organic compounds such as decolorization of dyeing waste water, decomposition treatment of wastewater containing hardly decomposable organic matter, and decomposition treatment of used ion exchange resin in nuclear facilities. To be effective.

  Furthermore, the present invention reduces the load of the removal process of precipitates such as sludge, which is often used in combination with the decomposition process by the Fenton reaction in the conventional method, and contributes to a significant improvement in economic efficiency.

FIG. 1 is a diagram for explaining the results of Examples 2-1 to 2-5 and Comparative Example 2-1.

In the method for treating an organic compound of the present invention, hydrogen peroxide and a compound (A) capable of generating a metal ion (I ₁ ) for causing a Fenton reaction are added to wastewater containing the organic compound, and the Fenton reaction is performed. This is a method for treating an organic compound in which the organic compound is oxidatively decomposed by a radical generated.

  Organic compounds that can be oxidatively decomposed by Fenton reaction include organic acids such as formic acid, gluconic acid and lactic acid; alcohols such as benzyl alcohol, tertiary butyl alcohol and glycerol; aldehydes such as acetaldehyde, benzaldehyde and formaldehyde; benzene, chlorobenzene and chlorophenol Aromatic compounds such as aniline, amines such as cyclic amine and diethylamine; dyes such as anthraquinone, diazo and monoazo; ethers such as tetrahydrofuran; ketones such as dihydroxyacetone and methylethylketone; ion exchange resins such as cation exchange resin and anion exchange resin Etc. One kind of organic compound may be contained in the wastewater, or two or more kinds thereof may be contained.

  Examples of the sewage include domestic wastewater and industrial wastewater containing the organic compounds. Specifically, the industrial wastewater includes dye exchange wastewater, livestock wastewater, ion exchange resins used for water treatment in nuclear facilities, etc. Examples include waste water.

As the compound (A), an iron (II) salt (a ₁ ) capable of generating Fe ²⁺ is preferably used. Hereinafter, an example of the compound (A) will be described using an iron (II) salt (a ₁ ) capable of generating Fe ²⁺ . Examples of the iron (II) salt (a ₁ ) capable of producing Fe ²⁺ include ferrous sulfate (FeSO ₄ ), ferrous fumarate, ferrous oxalate, ferrous chloride, and ferrous citrate. Examples thereof include sodium, ferrous gluconate, ferrous citrate, ferrous orotate, ferrous acetate, and hydrates thereof. The iron (II) salt (a ₁ ) capable of producing Fe ²⁺ may be used alone or in combination of two or more.

In this case, the radical generated by the Fenton reaction is a hydroxy radical (.OH). That is, the Fenton reaction is a reaction in which a hydroxy radical having a strong oxidizing power is generated from hydrogen peroxide and Fe ²⁺ derived from an iron (II) salt (a ₁ ) as shown in the following formula (1). .

H ₂ O ₂ + Fe ²⁺ → Fe ³⁺ + OH ⁻ + OH (1)
This hydroxy radical can be decomposed until the organic compound finally becomes carbon dioxide (CO ₂ ).

The organic compound treatment method of the present invention is a counter that combines with the waste water when the metal ions (I ₂ ) generated by the reaction of hydrogen peroxide and metal ions (I ₁ ) form a metal salt and precipitate. The compound (B) capable of generating a different anion from the anion is added, and the different anion is 1. added to the metal ion (I ₁ ) in the compound (A) added to the waste water. And a step of preventing precipitation of a compound formed from the metal ion (I ₁ ) and / or the metal ion (I ₂ ) by being present in an amount of 5 times equivalent (chemical equivalent) or more. Specifically, the method for treating the organic compound is a method in which Fe ³⁺ generated by the reaction of hydrogen peroxide and Fe ²⁺ forms a metal salt Fe (OH) ₃ and precipitates in the sewage. The compound (B) capable of generating a different anion from the hydroxy anion (OH ⁻ ), which is a counter anion, is added, and the Fe ² in the iron (II) salt (a ₁ ) added to the sewage is added to the sewage. ⁺ respect, including the step of preventing the precipitation of be present in the anion amount of more than 1.5 equivalents of the heterogeneous compounds formed from Fe ²⁺ and / or Fe ^3+.

In the conventional method for treating an organic compound using the Fenton reaction, Fe ³⁺ formed by the reaction of hydrogen peroxide and Fe ²⁺ forms a metal salt Fe (OH) ₃ , for example, as shown in the following formula (2). Then, there was a problem of precipitation.

Fe ³⁺ + 3OH ⁻ → Fe (OH) ₃ ↓ (2)
Further, it is considered that various reactions occur following the Fenton reaction represented by the above formula (1). There was also a problem that Fe ²⁺ and / or Fe ³⁺ precipitated by forming iron oxide due to their reaction. Thus, when precipitation of Fe (OH) ₃ and iron oxide (sludge) begins to occur, oxidative decomposition does not proceed, so hydrogen peroxide and iron (II) salt (a ₁ ) are further added to continue the treatment. Need arises. As a result, a large amount of precipitate was generated, and it was difficult to efficiently treat the organic compound.

In the present invention, this problem is solved by the step of adding the compound (B) to the sewage and causing the different anions to exist in a specific amount or more in the sewage as described above. Specifically, the compound (B) is added to the sewage to generate an anion different from the hydroxy anion (OH ⁻ ). Then, the heterogeneous anion is present in an amount of 1.5 times or more equivalent to Fe ²⁺ in the iron (II) salt (a ₁ ) added to the sewage, and Fe (OH) ) Precipitation of ₃ etc. can be prevented. The reason why precipitation of Fe (OH) ₃ or the like can be prevented is because the solubility of Fe (OH) ₃ increases due to the so-called heterogeneous ion effect.

In addition, after Fe ³⁺ is generated by the above formula (1), it is considered that conversion from Fe ³⁺ to Fe ²⁺ occurs in the sewage. In addition, it is thought that this conversion is based on the reaction in the sewage represented by the following formulas (1-1) to (1-5).

Fe ³⁺ + H ₂ O ₂ → FeOOH ²⁺ + H ⁺ (1-1)
FeOOH ²⁺ → Fe ²⁺ + OH ₂ (1-2)
H ₂ O ₂ + .OH → .OH ₂ + H ₂ O (1-3)
Fe ²⁺ + OH ₂ → Fe ³⁺ + HO ₂ c (1-4)
Fe ³⁺ + .OH ₂ → Fe ²⁺ + O ₂ + H ⁺ (1-5)
Then, it is considered that a hydroxy radical is newly generated from Fe ²⁺ converted from Fe ³⁺ and hydrogen peroxide. As described above, in the present invention, by adopting the above-described steps, the generation of precipitates can be suppressed, and the conversion from Fe ³⁺ to Fe ²⁺ occurs. Therefore, it takes a longer time than the conventional organic compound treatment method. Processing can continue. As a result, the amount of iron (II) salt (a ₁ ) added can be reduced, and organic compounds can be processed efficiently.

  In order to effectively prevent precipitation, it is desirable that the above-mentioned different kinds of anions be present in an amount of preferably 1.5 to 20 times equivalent.

Further, in the above step, the compound (B) capable of generating the different anion is converted into hydrogen peroxide and the iron (II) salt (a ₁ ) before oxidative decomposition of the organic compound with respect to sewage. Or may be added before hydrogen peroxide or the iron (II) salt (a ₁ ). In addition, the compound (B) may be added after the oxidative decomposition of the organic compound is started as long as the formation of the precipitate can maintain a state that does not cause a problem with respect to the oxidative decomposition of the organic compound. Further, the heterogeneous anion may be generated during the oxidative decomposition of the organic compound, and may be present in the above amount during the oxidative decomposition of the organic compound. That is, it is only necessary to maintain a state in which the formation of the precipitate does not cause a problem with respect to the oxidative decomposition of the organic compound.

In the present invention, the pH of sewage containing an organic compound to which hydrogen peroxide and a compound (A) capable of generating a metal ion (I ₁ ) for causing Fenton reaction are added is preferably 1 to 5, More preferably, it is adjusted to 1 to 3, and it is desirable to oxidatively decompose the organic compound with radicals generated by the Fenton reaction. When the pH is in the above range, generation of hydroxy radicals can be promoted. Further, it is preferable to keep the pH within the above range during the oxidative decomposition of the organic compound.

The compound (B) capable of generating the heterogeneous anion preferably contains at least one of sulfate, nitrate, chloride and carbonate. A compound (B) may be used independently and may be used in combination of 2 or more type. When these compounds (B) are used, the generated different anions are sulfate ion (SO ₄ ²⁻ ), nitrate ion (NO ₃ ⁻ ), chloride ion (Cl ⁻ ), carbonate ion (CO ₃ ^2−). ).

  Specifically, examples of the sulfate include sodium sulfate, potassium sulfate, and magnesium sulfate. Examples of nitrates include sodium nitrate, potassium nitrate, and magnesium nitrate. Examples of the chloride salt include sodium chloride, potassium chloride, and magnesium chloride. Examples of the carbonate include sodium carbonate, potassium carbonate, and magnesium carbonate.

  Moreover, it is also preferable that the compound (B) which can produce | generate the said different kind of anion contains the organic compound which has at least 1 sort (s) of a sulfo group, a nitro group, a chloro group, and a carboxyl group.

  When such a compound (B) is used, there is an advantage that a heterogeneous anion is rapidly generated by the addition of the compound (B), the formation of a precipitate is suppressed, and the organic compound can be decomposed efficiently and continuously.

  Moreover, in the said process, in order to adjust pH of sewage to the said range, you may add pH adjusters, such as a sulfuric acid, nitric acid, hydrochloric acid, and caustic soda. Note that the amount of the different anions present in the wastewater does not include the amount of anions derived from the pH adjuster. In other words, the amount of the different anions present in the waste water means the total amount of anions derived from the compound (A) and the compound (B).

Furthermore, in the above process, oil-based, silicon-based, polymer-based antifoaming agents, etc. are added to the sewage within a range that does not affect the effect of preventing precipitation of compounds formed from Fe ²⁺ and / or Fe ^3+. It may be added.

  Hereinafter, more specific embodiments of the present invention will be described.

<Embodiment 1>
In Embodiment 1 of the present invention, the sewage containing the organic compound is a dye wastewater containing a dye, and the compound (B) capable of generating the different anion is sulfate, nitrate, chloride or carbonate. Contains at least one. That is, in Embodiment 1 of the present invention, the hydroxyl radical generated by the Fenton reaction by adding hydrogen peroxide and an iron (II) salt (a ₁ ) capable of generating Fe ²⁺ to the dyeing wastewater containing the dye. The method of treating an organic compound that oxidatively decomposes the dye by Fe ³⁺ formed by the reaction of the hydrogen peroxide and Fe ²⁺ forms a metal salt Fe (OH) ₃ in the dyeing waste water. A compound (B) capable of generating an anion different from the hydroxy radical that combines during precipitation is added to the Fe ²⁺ in the iron (II) salt (a ₁ ) added to the waste water. On the other hand, the method includes the step of preventing the precipitation of the compound formed from Fe ²⁺ and / or Fe ³⁺ by causing the heterogeneous anion to be present in an amount of 1.5 times equivalent or more.

  Examples of the dye wastewater containing dyes include wastewater containing used azo dyes, anthraquinone dyes, phthalocyanine dyes, and the like.

The iron (II) salt (a ₁ ) may be any compound that can generate Fe ²⁺ when added to wastewater, and the compound (B) is different from hydroxy radicals when added to wastewater. Any compound that can generate an anion may be used, and specific examples include the compounds described above.

In Embodiment 1 of the present invention, more specifically, waste water is supplied to the reaction tank, and further, hydrogen peroxide, iron (II) salt (a ₁ ) capable of generating Fe ²⁺ , and different anions are generated. And possible compound (B). As a result, Fe ²⁺ is generated from the iron (II) salt (a ₁ ) in the waste water, and then a hydroxy radical is generated, and the oxidative decomposition of the dye starts.

  Here, in order to efficiently oxidize and decompose the dye, it is also preferable to stir the waste water in the reaction tank. Moreover, it is preferable to perform the oxidative decomposition process of dye at 10-40 degreeC, and it is more preferable to carry out at 20-30 degreeC.

  The COD (chemical oxygen demand) of the dye wastewater is usually 0.1 to 10 g / L.

The iron (II) salt (a ₁ ) capable of generating Fe ²⁺ is preferably added in an amount of 0.1 to 10 g with respect to 1 L of waste water.

  Hydrogen peroxide may be added in a preferable amount according to the amount of waste water, but it is preferably added as 2 to 70 w / v% hydrogen peroxide solution, and 30 to 70 w / v% hydrogen peroxide solution. It is more preferable to add as

  In order to increase the efficiency of the Fenton reaction, the pH of the wastewater is preferably adjusted to 1 to 5, more preferably 1 to 3. In order to adjust the pH, for example, sulfuric acid, nitric acid, hydrochloric acid or the like is added. Further, it is preferable to adjust the pH to be in the above range during the oxidative decomposition treatment of the dye. Further, the wastewater may be supplied to the reaction tank after pH adjustment in advance.

The compound (B) is an amount of 1.5 times equivalent or more, preferably 2 to 100 times equivalent, more preferably 2 times the amount of the heterogeneous anion with respect to Fe ²⁺ in the iron (II) salt (a ₁ ). It is added in such an amount that different kinds of anions can be present in an amount of ˜20 times equivalent. Incidentally, the addition of the compound (B) quickly generates a different anion in the waste water, and this different anion also includes a different anion generated from the iron (II) salt (a ₁ ) (however, pH Does not include anions generated from sulfuric acid or the like added to adjust the Therefore, it is preferable to add the compound (B) so that the total amount of these different anions is in the above range in the waste water.

In the first embodiment, since different anions exist in the waste water and precipitation of compounds formed from Fe ²⁺ and / or Fe ³⁺ , that is, Fe (OH) ₃ and iron oxide, can be prevented. Can last for a long time. If the wastewater contains the dye at the above concentration, the dye can be sufficiently decomposed when the treatment is usually carried out for 1 to 2 hours. However, according to the first embodiment, since sludge precipitation is suppressed during this period, the wastewater treatment can be performed efficiently. .

The wastewater, hydrogen peroxide and iron (II) salt (a ₁ ) capable of generating Fe ²⁺ may be supplied to the reaction tank at a time as described above, but may be supplied in multiple times. Or may be supplied continuously. Also in this case, it is preferable to supply the dye, hydrogen peroxide, and iron (II) salt (a ₁ ) capable of producing Fe ^{2+ so} that the total amount becomes the above-described amount.

Further, as described above, the compound (B) capable of generating a different anion is an iron (II) salt (a ₁ ) capable of generating hydrogen peroxide and Fe ²⁺ before starting the oxidation treatment of the dye. In addition, it may be added to the reaction vessel, but if the state where the above-mentioned precipitate formation does not cause a problem with respect to the oxidative decomposition of the dye can be maintained, the dye may be added after the oxidation treatment of the dye is started. Further, the compound (B) capable of generating different types of anions may be supplied to the reaction tank at a time as described above, but the state in which the formation of the precipitate does not pose a problem for the oxidative decomposition of the dye is maintained. If possible, it may be supplied in a plurality of times or continuously. In other words, at least before the end of the oxidation treatment of the dye, it is sufficient to add the different anions so that they are present in the above amounts.

<Embodiment 2>
In Embodiment 2 of the present invention, the waste water containing the organic compound is waste water containing a cation exchange resin having an acidic group and an anion exchange resin, and the cation exchange resin having the acidic group being the organic compound is This is a cation exchange resin which is the same as the compound (B) capable of generating an anion of the above and can be oxidized and decomposed by a hydroxy radical to generate an anion derived from an acidic group as the heterogeneous anion. That is, in Embodiment 2 of the present invention, hydrogen peroxide and an iron (II) salt (a ₁ ) capable of generating Fe ²⁺ are added to waste water containing a cation exchange resin having an acidic group and an anion exchange resin. And an organic compound treatment method in which the cation exchange resin and the anion exchange resin are oxidatively decomposed by hydroxy radicals generated by the Fenton reaction. Here, an anion which is different from the hydroxy radical which combines when Fe ³⁺ produced by the reaction of hydrogen peroxide and Fe ²⁺ forms a metal salt Fe (OH) ₃ and precipitates in the waste water. An anion derived from an acidic group of the cation exchange resin is generated, and in the wastewater, the heterogeneity is different from Fe ²⁺ in the iron (II) salt (a ₁ ) added to the wastewater. A step of preventing the precipitation of the compound formed from the Fe ²⁺ and / or Fe ³⁺ by causing the anion to be present in an amount of 1.5 times equivalent or more.

Waste water includes used cation exchange resins having acidic groups and anion exchange resins having basic groups. These ion exchange resin substrates are, for example, copolymers of styrene and divinylbenzene. The acidic group possessed by the cation exchange resin is, for example, a sulfonic acid group (—SO ³⁻ ). In nuclear facilities, cation exchange resins and anion exchange resins used for water treatment are often stored in the same storage tank. According to the second embodiment, it is possible to efficiently treat the exchange resin in which both are mixed and stored in this way. In addition, the exchange resin stored is difficult to decompose, so it has been conventionally treated by incineration. However, incineration methods generate harmful gases such as nitrogen oxides (NOx) and sulfur oxides (SOx). There was a problem. On the other hand, in the oxidative decomposition by the Fenton reaction, the exchange resin can be processed without generating these harmful gases.

The iron (II) salt (a ₁ ) may be any compound that can produce Fe ²⁺ when added to wastewater, and specifically includes the compounds described above.

In Embodiment 2 of the present invention, more specifically, iron (II) that can supply wastewater containing used cation exchange resin and anion exchange resin to the reaction vessel, and further generate hydrogen peroxide and Fe ^2+. Salt (a ₁ ) is added. As a result, Fe ²⁺ is generated from the iron (II) salt (a ₁ ) in the sewage, and then a hydroxy radical is generated, and oxidative decomposition of the cation exchange resin and the anion exchange resin starts. Oxidative decomposition of the cation exchange resin produces different anions derived from acidic groups, for example, sulfate ions derived from sulfonic acid groups (—SO ³⁻ ), in the wastewater.

  Here, in order to efficiently oxidatively decompose the cation exchange resin and the anion exchange resin, it is also preferable to stir the waste water in the reaction tank. Moreover, it is preferable to perform the oxidative decomposition process of a cation exchange resin and an anion exchange resin at 90-110 degreeC.

The actual waste of the nuclear power plant is stored in a storage tank in a state where solids and liquids such as cation exchange resin, anion exchange resin, and cladding are mixed. During the wastewater treatment, the solid concentration is usually adjusted to 10 to 200 g / L and supplied to the reaction vessel. Further, the cation exchange resin is usually contained in an amount of 30 to 70% by mass, preferably 40 to 60% by mass, and the anion exchange resin is contained in an amount of 30 to 70% by mass, preferably 40 to 60% by mass. Here, the total amount of the cation exchange resin and the anion exchange resin is 100% by mass. As the ratio of the anion exchange resin increases, the effect of preventing precipitation of Fe (OH) ₃ according to the present invention is obtained.

The iron (II) salt (a ₁ ) capable of generating Fe ²⁺ is preferably added in an amount of 0.001 to 0.1 mol with respect to 1 L of waste water containing a cation exchange resin and an anion exchange resin. More preferably, it is added in an amount of 005 to 0.02 mol.

  Hydrogen peroxide may be added in an appropriate amount according to the amount of ion exchange resin contained in the waste water, but it is preferably added as 2 to 70 w / v% hydrogen peroxide water, and 30 to 70 w / v. It is more preferable to add as% hydrogen peroxide solution.

  In order to increase the efficiency of the Fenton reaction, the pH of the sewage is preferably adjusted to 1 to 5, more preferably 1 to 3. In order to adjust the pH, for example, sulfuric acid, nitric acid, hydrochloric acid or the like is added. Moreover, it is preferable to adjust pH so that it may become the said range during performing the oxidative decomposition process of the said ion exchange resin. Further, the wastewater may be supplied to the reaction tank after pH adjustment in advance.

In Embodiment 2, the amount of the different anion is 1.5 times equivalent or more, preferably 2 to 100 times equivalent to Fe ²⁺ in the iron (II) salt (a ₁ ) in the waste water. Preferably, a different anion is present in an amount of 2 to 50 times equivalent. This heteroanion includes an anion derived from an acidic group produced by oxidative decomposition of a cation exchange resin, and a heteroanion produced from an iron (II) salt (a ₁ ) (however, in order to adjust pH) Does not include anions generated from sulfuric acid added to Here, since the concentration of solids in the wastewater, the ratio of the cation exchange resin and the anion exchange resin, and the amount of the iron (II) salt (a ₁ ) are within the above ranges, these different anions in the wastewater The total amount of can also be adjusted within the above range.

In Embodiment 2, since the heterogeneous anion exists in the wastewater and precipitation of a compound formed from Fe ²⁺ and / or Fe ³⁺ , that is, Fe (OH) ₃ can be prevented, the oxidation treatment of the ion exchange resin is performed. Can last for a long time. In the case of waste water containing an ion exchange resin at the above concentration, the ion exchange resin can be decomposed sufficiently when treated for 5 to 10 hours. However, according to the second embodiment, since sedimentation of sludge is suppressed during this period, it is efficient. Wastewater treatment can be performed. Further, according to the second embodiment, there is an advantage that the cation exchange resin to be oxidatively decomposed also serves as a supply source of different ions. In the second embodiment, at the start of the oxidative decomposition of the ion exchange resin, an anion derived from an acidic group as a different kind of anion is not generated in the wastewater. However, as the cation exchange resin is oxidatively decomposed by the Fenton reaction, An anion derived from an acidic group is generated. Thus, until a certain amount of anion derived from an acidic group is formed, precipitation of Fe (OH) ₃ and iron oxide does not usually occur to the extent that it causes a problem for oxidative decomposition of the ion exchange resin.

The iron (II) salt (a ₁ ) capable of generating waste water, hydrogen peroxide and Fe ²⁺ may be supplied to the reaction tank at a time as described above, but may be supplied in multiple times. Or may be supplied continuously. Also in this case, it is preferable that the total amount of each of the iron (II) salt (a ₁ ) capable of generating the ion exchange resin, hydrogen peroxide, and Fe ²⁺ is supplied to the above amount.

By the way, depending on the ratio of the cation exchange resin and the anion exchange resin, the amount of acidic groups of the cation exchange resin in the wastewater, etc., there may be a case where the heterogeneous anion cannot be present in the amount within the above range. In this case, waste water containing used cation exchange resin and anion exchange resin is supplied to the reaction tank, and hydrogen peroxide and iron (II) salt (a ₁ ) capable of producing Fe ²⁺ are added. At the same time, the compound (B) capable of generating the different types of anions used in Embodiment 1 may be added. In this way, the amount of different anions in the sewage may be adjusted.

When the compound (B) capable of generating a different anion is used in combination, before starting the oxidation treatment of the on-exchange resin, an iron (II) salt (a) capable of generating hydrogen peroxide and Fe ²⁺ ₁ ) may be added to the reaction vessel together with the above, but if the state where the precipitate formation does not pose a problem for oxidative decomposition of the ion exchange resin can be maintained, the oxidation treatment of the ion exchange resin is started. May be added. Further, the compound (B) capable of generating different types of anions may be supplied to the reaction tank at a time as described above, but the state in which the formation of the precipitate does not pose a problem for the oxidative decomposition of the ion exchange resin. Can be supplied in a plurality of times or continuously. In other words, at least before the end of the oxidation treatment of the on-exchange resin, it is sufficient that the different types of anions are added so as to exist in the above amounts.

<Other embodiments>
In Embodiments 1 and 2, a copper (I) salt (a ₂ ) may be used instead of the iron (II) salt (a ₁ ). The Fenton reaction in this case is represented by the following formula (3).

^{_{H 2 O 2 + Cu + →}} Cu 2+ + OH - + · OH
In Embodiments 1 and 2, the waste water after the organic compound is subjected to oxidative decomposition treatment may be further subjected to a treatment for removing Fe ²⁺ and / or Fe ³⁺ .

  In Embodiment 1, instead of dye wastewater containing dyes, livestock wastewater containing persistent organic compounds or domestic wastewater containing organic compounds containing nitrogen or phosphorus may be used, and benzene, toluene, formaldehyde For example, groundwater containing a volatile organic compound (VOC) that may be harmful to health may be used. In any case, precipitation of the metal ion catalyst used for the Fenton reaction can be prevented, and such an organic compound can be decomposed efficiently and continuously.

  The present invention relates to the following.

[1] Hydrogen peroxide and a compound (A) capable of generating a metal ion (I ₁ ) for causing a Fenton reaction are added to sewage containing the organic compound, and the organic compound is generated by a radical generated by the Fenton reaction. A method of treating an organic compound that oxidatively decomposes, wherein the metal ion (I ₂ ) generated by the reaction between the hydrogen peroxide and the metal ion (I ₁ ) forms a metal salt and precipitates in the waste water. A compound (B) capable of generating a different anion from the counter anion that combines with the metal ion (I ₁ ) in the compound (A) added to the sewage is added to the sewage. In the amount of 1.5 times equivalent or more to prevent precipitation of the compound formed from the metal ion (I ₁ ) and / or the metal ion (I ₂ ). A method for treating organic compounds.

  Since the step of preventing precipitation of the compound is included, the generation of the precipitate is suppressed, and the organic compound can be decomposed efficiently and continuously.

[2] The compound (A) capable of generating the metal ion (I ₁ ) for causing the Fenton reaction is an iron (II) salt (a ₁ ) capable of generating Fe ^2+, and is generated by the Fenton reaction. The treatment method according to [1], wherein the radical to be treated is a hydroxy radical.

The organic compound can be efficiently and continuously decomposed by the Fenton reaction using the iron (II) salt (a ₁ ) capable of generating Fe ²⁺ .

[3] The pH of sewage containing an organic compound to which the hydrogen peroxide and the compound (A) capable of generating a metal ion (I ₁ ) for causing the Fenton reaction are added is adjusted to 1 to 5, and the Fenton reaction is performed. The treatment method according to [1] or [2], wherein the organic compound is oxidatively decomposed by radicals generated by the above.

  By setting the pH of the sewage within the above range, hydroxy radicals can be generated efficiently.

  [4] The waste water containing the organic compound is waste water containing a cation exchange resin having an acidic group and an anion exchange resin, and the cation exchange resin having the acidic group being the organic compound generates the heterogeneous anion. [1] to [3], wherein the cation exchange resin is the same as the compound (B) to be obtained and is oxidatively decomposed by a hydroxyl radical to generate an anion derived from an acidic group as the heterogeneous anion. The processing method of the organic compound as described in any one.

  The heterogeneous anion generated as the cation exchange resin having an acidic group undergoes oxidative decomposition suppresses the formation of precipitates, and the organic compound can be decomposed efficiently and continuously.

  [5] The wastewater containing the organic compound is dyed wastewater containing a dye, and the compound (B) capable of generating the different anions includes at least one of sulfate, nitrate, chloride and carbonate. The method for treating an organic compound according to any one of [1] to [3], wherein:

  The heterogeneous anion produced by the compound (B) suppresses the formation of a precipitate, and the organic compound can be decomposed efficiently and continuously.

  [6] Any one of [1] to [3], wherein the compound (B) capable of generating the different anion includes at least one of sulfate, nitrate, chloride and carbonate. The processing method described in one.

  [7] The compound (B) capable of generating a different kind of anion includes an organic compound having at least one of a sulfo group, a nitro group, a chloro group, and a carboxyl group [1] to [3] The processing method as described in any one of these.

  According to these compounds (B), different anions are rapidly generated, the formation of precipitates is suppressed, and the organic compound can be decomposed efficiently and continuously.

[Example]
Hereinafter, although an example is given and the present invention is explained, the present invention is not limited to these.

[Example 1]
For dyeing waste liquid (COD of about 900 mg / L) containing 1.6 g / L of Levafix Turquoise Blue E-BA (Levafix Turquoise Blue E-BA) manufactured by Daistar as a dye, the following conditions were used: A degradation test was performed. That is, to 1 L of dyeing waste liquid, 6.0 g of ferrous sulfate heptahydrate salt as a Fenton reagent, 18 g of 35% hydrogen peroxide water, and 10 g of sodium sulfate as a different anion supplier were added, The decomposition test for 1 hour was conducted on the conditions of 25-30 degreeC and pH = 2.3. Before and after the above decomposition test, the change in the transmittance of the waste liquid and the change in the iron ion concentration in the waste liquid were measured. However, the transmittance of the stock solution is 0%. The transmittance was measured with a UV / visible spectrophotometer DU 730 manufactured by Beckman Coulter, Inc. at a wavelength of 625 nm, and the iron ion concentration was measured with an ICP emission spectroscopic analyzer SPS5520 manufactured by SII Nano Technology.

The pH was adjusted with a 0.5 mol / L sulfuric acid aqueous solution, and the pH of the waste liquid was measured using a pH meter F-51 manufactured by Horiba. Further, in Example 1, the heterogeneous anion (sulfate ion) derived from the ferrous sulfate heptahydrate salt and sodium sulfate was compared with Fe ^{2+ of the} ferrous sulfate heptahydrate salt in the waste liquid. It was present in an amount equivalent to 4.5 times.

[Comparative Example 1] (Conventional method)
A dye waste solution containing 1.6 g / L of Revafix Turquoise Blue E-BA (Levafix Turquoise Blue E-BA) manufactured by Daistar as a dye was subjected to a decomposition test by the Fenton reaction under the following conditions. That is, to 1 L of dyeing waste liquid, 6.0 g of ferrous sulfate heptahydrate salt and 18 g of 35% hydrogen peroxide solution were added as Fenton reagent, and the temperature was 25 to 30 ° C. and the pH was 2.3. Under the conditions, a 1 hour decomposition test was performed. However, the transmittance of the stock solution is 0%. Changes in transmittance and iron ion concentration were measured by the same method as in Example 1.

The pH was adjusted with a 0.5 mol / L sulfuric acid aqueous solution, and the pH of the waste liquid was measured using a pH meter F-51 manufactured by Horiba. In Comparative Example 1, different anions (sulfate ions) derived from ferrous sulfate heptahydrate salt are equivalent to 1-fold equivalent to Fe ²⁺ of ferrous sulfate heptahydrate salt in the waste liquid. Was present in an amount.

  The measurement results of transmittance and iron ion concentration in Example 1 and Comparative Example 1 obtained as described above are as shown in Table 1.

[Example 2-1]
A dye waste solution containing 1.6 g / L of Revafix Turquoise Blue E-BA (Levafix Turquoise Blue E-BA) manufactured by Daistar as a dye was subjected to a decomposition test by the Fenton reaction under the following conditions. That is, to 1 L of dyeing waste liquid, 6.0 g of ferrous sulfate heptahydrate salt as a Fenton reagent, 18 g of 35% hydrogen peroxide water, and 1.5 g of sodium sulfate as a different anion supplier are added. The decomposition test was conducted for 1 hour under the conditions of a temperature of 25 to 30 ° C. and a pH of 2.0. Before and after the above decomposition test, the change in the transmittance of the waste liquid and the change in the iron ion concentration in the waste liquid were measured. However, the transmittance of the stock solution is 0%. The transmittance was measured with a UV / visible spectrophotometer DU 730 manufactured by Beckman Coulter, Inc. at a wavelength of 625 nm, and the iron ion concentration was measured with an ICP emission spectroscopic analyzer SPS5520 manufactured by SII Nano Technology.

The pH was adjusted with a 0.5 mol / L sulfuric acid aqueous solution, and the pH of the waste liquid was measured using a pH meter F-51 manufactured by Horiba. Further, in Example 2, the heterogeneous anion (sulfate ion) derived from the ferrous sulfate heptahydrate salt and sodium sulfate was compared with Fe ^{2+ of the} ferrous sulfate heptahydrate salt in the waste liquid. It was present in an amount equivalent to 1.5 times.

[Examples 2-2 to 2-5]
In Examples 2-2 to 2-5, 3.0 g, 6.0 g, 12 g, or 18 g of sodium sulfate was used instead of 1.5 g of sodium sulfate as a different anion supplier for 1 L of dyeing waste liquid. Except for this, the same procedure as in Example 2-1 was performed.

In Examples 2-2 to 2-5, the ferrous sulfate heptahydrate salt and the heterogeneous anion (sulfate ion) derived from sodium sulfate were added to the Fe ^{2+ of the} ferrous sulfate heptahydrate salt in the waste liquid. It was present in an amount of 2, 3, 5 or 7 times the equivalent.

  In Examples 2-1 to 2-5, the transmittance of the waste liquid was 99% after the decomposition test was performed.

[Comparative Example 2] (Conventional method)
A dye waste solution containing 1.6 g / L of Revafix Turquoise Blue E-BA (Levafix Turquoise Blue E-BA) manufactured by Daistar as a dye was subjected to a decomposition test by the Fenton reaction under the following conditions. That is, to 1 L of dyeing waste liquid, 6.0 g of ferrous sulfate heptahydrate salt and 18 g of 35% hydrogen peroxide solution were added as Fenton reagent, and the temperature was 25 to 30 ° C. and the pH was 2.3. Under the conditions, a 1 hour decomposition test was performed. However, the transmittance of the stock solution is 0%. Changes in transmittance and iron ion concentration were measured in the same manner as in Example 2-1.

In Comparative Example 2, the different anion (sulfate ion) derived from the ferrous sulfate heptahydrate salt is in an amount equivalent to one-fold equivalent to Fe ^{2+ of the} ferrous sulfate heptahydrate salt in the waste liquid. Existed.

  The measurement results of the iron ion concentration in Examples 2-1 to 2-5 and Comparative Example 2 obtained as described above are as shown in FIG. In addition, the plot in FIG. 1 represents the results of Comparative Example 2 and Examples 2-1 to 2-5 in order from the left.

[Example 3]
A dye waste solution containing 1.6 g / L of Revafix Turquoise Blue E-BA (Levafix Turquoise Blue E-BA) manufactured by Daistar as a dye was subjected to a decomposition test by the Fenton reaction under the following conditions. That is, to 1 L of dyeing waste liquid, 6.0 g of ferrous sulfate heptahydrate salt as a Fenton reagent, 18 g of 35% hydrogen peroxide water, and 17 g of sodium nitrate as a different anion supplier were added, The degradation test was conducted for 2 hours under the conditions of 25 to 30 ° C. and pH = 2.3. Before and after the above decomposition test, the change in the transmittance of the waste liquid and the change in the iron ion concentration in the waste liquid were measured. However, the transmittance of the stock solution is 0%. The transmittance was measured with a UV / visible spectrophotometer DU 730 manufactured by Beckman Coulter, Inc. at a wavelength of 625 nm, and the iron ion concentration was measured with an ICP emission spectroscopic analyzer SPS5520 manufactured by SII Nano Technology.

The pH was adjusted with a 0.5 mol / L sulfuric acid aqueous solution, and the pH of the waste liquid was measured using a pH meter F-51 manufactured by Horiba. In Example 3, different anions (sulfate ion and nitrate ion) derived from ferrous sulfate heptahydrate salt and sodium nitrate were converted into ferrous sulfate heptahydrate salt Fe ²⁺ in the waste liquid. In contrast, it was present in an amount of 11 equivalents.

[Comparative Example 3] (Conventional method)
A dye waste solution containing 1.6 g / L of Revafix Turquoise Blue E-BA (Levafix Turquoise Blue E-BA) manufactured by Daistar as a dye was subjected to a decomposition test by the Fenton reaction under the following conditions. That is, to 1 L of dyeing waste liquid, 6.0 g of ferrous sulfate heptahydrate salt and 18 g of 35% hydrogen peroxide solution were added as Fenton reagent, and the temperature was 25 to 30 ° C. and the pH was 2.3. A 2-hour degradation test was performed under the conditions. However, the transmittance of the stock solution is 0%. Changes in transmittance and iron ion concentration were measured by the same method as in Example 3.

The pH was adjusted with a 0.5 mol / L sulfuric acid aqueous solution, and the pH of the waste liquid was measured using a pH meter F-51 manufactured by Horiba. In Comparative Example 3, the different anion (sulfate ion) derived from the ferrous sulfate heptahydrate salt is equivalent to 1-fold equivalent in the waste liquid with respect to Fe ^{2+ of the} ferrous sulfate heptahydrate salt. Was present in an amount.

  The measurement results of transmittance and iron ion concentration in Example 3 and Comparative Example 3 obtained as described above are as shown in Table 2.

[Example 4]
A dye waste solution containing 1.6 g / L of Revafix Turquoise Blue E-BA (Levafix Turquoise Blue E-BA) manufactured by Daistar as a dye was subjected to a decomposition test by the Fenton reaction under the following conditions. That is, for 1 L of dyeing waste liquid, 6.0 g of ferrous sulfate heptahydrate salt as a Fenton reagent, 18 g of 35% hydrogen peroxide water, and 25 g of magnesium sulfate heptahydrate as a supplier of different anions. Then, a decomposition test was conducted for 2 hours under the conditions of a temperature of 25 to 30 ° C. and a pH of 2.3. Before and after the above decomposition test, the change in the transmittance of the waste liquid and the change in the iron ion concentration in the waste liquid were measured. However, the transmittance of the stock solution is 0%. The transmittance was measured with a UV / visible spectrophotometer DU 730 manufactured by Beckman Coulter, Inc. at a wavelength of 625 nm, and the iron ion concentration was measured with an ICP emission spectroscopic analyzer SPS5520 manufactured by SII Nano Technology.

The pH was adjusted with a 0.5 mol / L sulfuric acid aqueous solution, and the pH of the waste liquid was measured using a pH meter F-51 manufactured by Horiba. Further, in Example 4, the different anions (sulfate ions) derived from the ferrous sulfate heptahydrate salt and magnesium sulfate heptahydrate were added to the Fe ^{2+ of the} ferrous sulfate heptahydrate salt in the waste liquid. It was present in an amount equivalent to 6 times the amount.

[Comparative Example 4] (Conventional method)
A dye waste solution containing 1.6 g / L of Revafix Turquoise Blue E-BA (Levafix Turquoise Blue E-BA) manufactured by Daistar as a dye was subjected to a decomposition test by the Fenton reaction under the following conditions. That is, to 1 L of dyeing waste liquid, 6.0 g of ferrous sulfate heptahydrate salt and 18 g of 35% hydrogen peroxide solution were added as Fenton reagent, and the temperature was 25 to 30 ° C. and the pH was 2.3. A 2-hour degradation test was performed under the conditions. However, the transmittance of the stock solution is 0%. Changes in transmittance and iron ion concentration were measured by the same method as in Example 4.

The pH was adjusted with a 0.5 mol / L sulfuric acid aqueous solution, and the pH of the waste liquid was measured using a pH meter F-51 manufactured by Horiba. In Comparative Example 4, the different anion (sulfate ion) derived from the ferrous sulfate heptahydrate salt is equivalent to 1-fold equivalent to the ferrous sulfate heptahydrate salt Fe ^{2+ in} the waste liquid. Was present in an amount.

  The measurement results of the transmittance and iron ion concentration in Example 4 and Comparative Example 4 obtained as described above are as shown in Table 3.

[Example 5]
A waste liquid containing 65 g / L of an anion exchange resin (C ₁₂ H ₁₈ NOH) and 55 g / L of a cation exchange resin (C ₈ H ₇ SO ₃ H), which are hardly decomposable organic substances, was subjected to Fenton reaction under the following conditions. A degradation test was performed. That is, 5.6 g of ferrous sulfate heptahydrate salt was added to 1 L of dyeing waste liquid, and a temperature of 95 to 105 ° C., pH = 1 while continuously supplying 35% hydrogen peroxide water at 150 ml / h. A decomposition test for 8 hours was performed under the conditions of ~ 3. Before and after performing the above-described decomposition test, the decomposition rate of organic carbon in the waste liquid and the change in iron ion concentration were measured. The decomposition rate of organic carbon was measured with a total organic carbon meter TOC-500A manufactured by Shimadzu, and the iron ion concentration was measured with an ICP emission spectroscopic analyzer SPS5520 manufactured by SII Nano Technology. The sulfate ion concentration was measured with an ion chromatograph ICS-3000 manufactured by Dionex.

The pH was adjusted with a 64% sulfuric acid aqueous solution and a 25% caustic soda aqueous solution, and the pH of the waste liquid was measured using a pH meter F-51 manufactured by Horiba. Further, in Example 5, the ferrous sulfate heptahydrate salt and the different anion (sulfate ion) derived from the cation exchange resin are contained in the waste liquid with respect to Fe ^{2+ of the} ferrous sulfate heptahydrate salt. Before the test, it was present in an amount of 1 equivalent, and at the end of the test, it was present in an amount of 8 equivalents. Thus, it is considered that during the test, sulfate ions derived from the sulfonic acid group (—SO ³⁻ ) were generated by oxidative decomposition of the cation exchange resin.

[Example 6]
A waste liquid containing 60 g / L of an anion exchange resin (C ₁₂ H ₁₈ NOH) and 60 g / L of a cation exchange resin (C ₈ H ₇ SO ₃ H), which are hardly decomposable organic substances, was subjected to Fenton reaction under the following conditions. A degradation test was performed. That is, 5.6 g of ferrous sulfate heptahydrate salt was added to 1 L of dyeing waste liquid, and a temperature of 95 to 105 ° C., pH = 1 while continuously supplying 35% hydrogen peroxide water at 150 ml / h. A decomposition test for 8 hours was performed under the conditions of ~ 3. Before and after performing the above-described decomposition test, the decomposition rate of organic carbon in the waste liquid and the change in iron ion concentration were measured. The decomposition rate of organic carbon was measured with a total organic carbon meter TOC-500A manufactured by Shimadzu, and the iron ion concentration was measured with an ICP emission spectroscopic analyzer SPS5520 manufactured by SII Nano Technology. The sulfate ion concentration was measured with an ion chromatograph ICS-3000 manufactured by Dionex.

The pH was adjusted with a 64% sulfuric acid aqueous solution and a 25% caustic soda aqueous solution, and the pH of the waste liquid was measured using a pH meter F-51 manufactured by Horiba. Further, in Example 6, ferrous sulfate heptahydrate salt, a heterogeneous anion (sulfate ion) derived from a cation exchange resin, was reduced in the waste liquid with respect to Fe ^{2+ of} ferrous sulfate heptahydrate salt. Before the test, it was present in an amount of 1-fold equivalent, and at the end of the test, it was present in an amount of 8.5-fold equivalent. Thus, it is considered that during the test, sulfate ions derived from the sulfonic acid group (—SO ³⁻ ) were generated by oxidative decomposition of the cation exchange resin.

[Comparative Example 5] (Conventional method)
A waste liquid containing 130 g / L of an anion exchange resin (C ₁₂ H ₁₈ NOH), which is a hardly decomposable organic substance, was subjected to a decomposition test by the Fenton reaction under the following conditions. That is, 5.6 g of ferrous sulfate heptahydrate salt was added to 1 L of dyeing waste liquid, and 35% hydrogen peroxide solution was continuously supplied at 180 ml / h, while the temperature was 95 to 105 ° C., pH = 1. A decomposition test for 8 hours was performed under the conditions of ~ 3. Changes in organic carbon decomposition rate and iron ion concentration in the waste liquid were measured by the same method as in Example 5.

The pH was adjusted with a 64% sulfuric acid aqueous solution and a 25% caustic soda aqueous solution, and the pH of the waste liquid was measured using a pH meter F-51 manufactured by Horiba. In Comparative Example 5, the different anion (sulfate ion) derived from the ferrous sulfate heptahydrate salt was added to the Fe ² sulfate heptahydrate salt in the waste liquid both before and at the end of the test. It was present in an amount equivalent to 1 fold with respect to ⁺ .

  Table 4 shows the measurement results of the organic carbon decomposition rate and the iron ion concentration in Examples 5 and 6 and Comparative Example 5 obtained as described above.

  As is clear from the results of the above examples, in the present invention, even after the decomposition of the organic compound, the iron ion concentration does not decrease so much and the formation of precipitates is suppressed. And it can be seen that it can be continuously decomposed.

The iron ion concentration measured in the examples is the total concentration of Fe ³⁺ in addition to Fe ²⁺ . Therefore, in the embodiment of the present invention, it is understood that the present in wastewater without precipitation even when the Fe ²⁺ rather than Fe ^3+. This Fe ³⁺ is again converted to Fe ²⁺ by the above formulas (1-1) to (1-5), and it is considered that a new hydroxy radical can be generated by the above formula (1). Therefore, in the Example of this invention, it is also possible to add a sewage and to decompose | disassemble the organic compound in it continuously.

  According to the present invention, organic compounds contained in domestic wastewater and industrial wastewater can be oxidatively decomposed and rendered harmless. The present invention can also be applied to decolorization treatment by oxidative decomposition of dyed wastewater and livestock wastewater in the textile and dyeing industry, and treatment by oxidative decomposition of hardly decomposable organic substances such as used ion exchange resins. Furthermore, volatile organic compounds (VOC) can be oxidatively decomposed and rendered harmless.

Claims (7)

Hydrogen peroxide and a compound (A) capable of generating a metal ion (I ₁ ) for causing a Fenton reaction are added to waste water containing an organic compound, and the organic compound is oxidatively decomposed by radicals generated by the Fenton reaction. A method for treating an organic compound comprising:
In the sewage, a counter anion that is combined with the metal ion (I ₂ ) generated by the reaction of the hydrogen peroxide and the metal ion (I ₁ ) to form a metal salt forms a different anion. Adding the resulting compound (B),
During said wastewater, the metal ion (I ₁₎ in the compound added to the sewerage (A), be present in the anion amount of more than 1.5 equivalents of said heterologous, the metal ion (I ₁ And / or a process for preventing precipitation of the compound formed from the metal ion (I ₂ ). The compound (A) capable of generating the metal ion (I ₁ ) for causing the Fenton reaction is an iron (II) salt (a ₁ ) capable of generating Fe ²⁺ , and the radical generated by the Fenton reaction is The treatment method according to claim 1, wherein the treatment method is a hydroxy radical. The wastewater containing the organic compound to which the hydrogen peroxide and the compound (A) capable of generating the metal ion (I ₁ ) for causing the Fenton reaction are added is adjusted to pH 1 to 5, and generated by the Fenton reaction. The processing method according to claim 1, wherein the organic compound is oxidatively decomposed by radicals. The wastewater containing the organic compound is wastewater containing a cation exchange resin having an acidic group and an anion exchange resin,
The cation exchange resin having an acidic group, which is the organic compound, is the same as the compound (B) capable of generating the different anion, and is oxidatively decomposed by a hydroxy radical, and the anion derived from the acidic group as the different anion. It is a cation exchange resin which can produce | generate, The processing method of the organic compound of any one of Claims 1-3 characterized by the above-mentioned. The sewage containing the organic compound is dyed wastewater containing a dye,
The organic compound according to any one of claims 1 to 3, wherein the compound (B) capable of generating a heterogeneous anion contains at least one of sulfate, nitrate, chloride and carbonate. Compound processing method.   The treatment according to any one of claims 1 to 3, wherein the compound (B) capable of generating a heterogeneous anion contains at least one of sulfate, nitrate, chloride and carbonate. Method.   The compound (B) capable of generating the heterogeneous anion includes an organic compound having at least one of a sulfo group, a nitro group, a chloro group, and a carboxyl group. The processing method as described in.

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