JP7228232B2 - Heterogeneous Fenton reaction catalyst - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act (1) Date of posting on the website March 6, 2018 Website address http://www. csj. jp/nenkai/98haru/index. html https://nenkai. csj. jp/Proceeding/index/year/2018 (2) Publication date March 6, 2018 Publication The 98th Chemical Society of Japan Annual Meeting (2018) Proceedings (DVD/USB) (3) Date of publication on the website 2018 March 13, 2009 Website address http://www. csj. jp/nenkai/98haru/index. html https://itunes. apple. com/jp/app/id1354316374 (App Store) https://play. google. com/store/apps/details? id=jp. atlas. procguide. csj98th (Google Play) (4) Date March 20, 2018 to March 23, 2018 Meeting name, venue The 98th Chemical Society of Japan Annual Meeting (2018) Nihon University College of Science and Technology, Funabashi Campus (Funabashi City, Chiba Prefecture) 7-24-1 Narashinodai) (5) Posting date of website May 21, 2018 Website address http://jaci-gsc. com/7th/ (6) Publication date June 14, 2018 Publication 7th JACI/GSC Symposium Proceedings (7) Date June 14, 2018 to June 15, 2018 Meeting name, Venue No. 7th JACI/GSC Symposium ANA Crowne Plaza Hotel Kobe (1-chome, Kitano-cho, Chuo-ku, Kobe) (8) Publication date May 1, 2018 Publication 2018 International Symposium on Engineering and Applied Science Conference Proceedings August 7-9, 2018 Guam, USA (9) Date of publication June 1, 2018 Publication 2018 International Symposium on Engineering and Applied Science Conference Proceedings August 7-9, 2018 Guam, USA

Article 30, Paragraph 2 of the Patent Law applies (10) Date of issue: July 1, 2018 Publication: 2018 International Symposium on Engineering and Applied Science Conference Proceedings, August 7-9, 2018 Guam, USA (11) Date of issue: August 2, 2018 １日刊行物 ２０１８ Ｉｎｔｅｒｎａｔｉｏｎａｌ Ｓｙｍｐｏｓｉｕｍ ｏｎ Ｅｎｇｉｎｅｅｒｉｎｇ ａｎｄ Ａｐｐｌｉｅｄ Ｓｃｉｅｎｃｅ Ｃｏｎｆｅｒｅｎｃｅ Ｐｒｏｃｅｅｄｉｎｇｓ Ａｕｇｕｓｔ ７－９，２０１８ Ｇｕａｍ，ＵＳＡ （１２）開催日 ２０１８年８月７日から２０１８年８月９日 集会名、開催場所 ２０１８ Ｉｎｔｅｒｎａｔｉｏｎａｌ Ｓｙｍｐｏｓｉｕｍ ｏｎ Engineering and Applied Science Hyatt Regency Guam (1155 San Vitres Road, Tumon, Guam, USA) (13) Website publication date September 19, 2018 Website address http://www. shokubai. org/122/index. html (14) Publication date: September 19, 2018 Publication: Proceedings of the 122nd Symposium on Catalysis (15) Date: September 26, 2018 to September 28, 2018 Name of meeting, Venue: The 122nd Symposium on Catalysis Meeting Hokkaido University of Education Hakodate Campus (1-2 Yawata-cho, Hakodate-shi, Hokkaido) (16) Publication date October 26, 2018 Publication OKCAT2018 (Osaka-Kansai International Symposium on Catalysis) Abstracts (17) Date 2018 October 26th to October 27th, 2018 Name of meeting, venue OKCAT2018 (Osaka-Kansai International Symposium on Catalysis) Kansai University Shobunkan ((3-3-35 Yamate-cho, Suita-shi, Osaka))

The present invention relates to a heterogeneous Fenton reaction catalyst and the like.

The Fenton reaction using hydrogen peroxide is one of the cleanest ways to detoxify organic pollutants in water. Iron ions (Fe ²⁺ , Fe ³⁺ ) are widely known as catalysts for the Fenton reaction. (・OH) can be generated.
(1) ^Fe2 + _{+ H2O2} → ^Fe3 + + OH + OH ^-
(2) Fe ³⁺ +H ₂ O ₂ →Fe ²⁺ +.O ₂ ⁻ +2H ⁺ .

However, although there are many reports of homogeneous Fenton reactions using iron ions as water-soluble substances (iron sulfate, etc.), there are few reports of heterogeneous Fenton reactions that do not use water-soluble substances. For example, Patent Document 1 describes a heterogeneous Fenton reaction using a catalyst in which a metal such as iron is supported on an inorganic carrier such as zeolite. The heterogeneous Fenton reaction is considered more desirable because the catalyst can be recovered and reused. However, the efficiency of the heterogeneous Fenton reaction is extremely low, and there is no report of a heterogeneous Fenton reaction with an efficiency comparable to that of the homogeneous Fenton reaction.

Japanese Patent Application Laid-Open No. 2014-198286

An object of the present invention is to provide a heterogeneous Fenton reaction catalyst.

As a result of intensive research in view of the above problems, the present inventors obtained a layered double hydroxide containing divalent iron ions, trivalent metal ions, and anions and/or the layered double hydroxide structure after collapse. It has been found that the amorphous composite hydroxide obtained is useful as a heterogeneous Fenton reaction catalyst. Furthermore, it has been found that the preferred form of the layered double hydroxide enables a heterogeneous Fenton reaction with an efficiency comparable to or exceeding that of the homogeneous Fenton reaction.

That is, the present invention includes the following aspects.

Section 1. A heterogeneous Fenton reaction catalyst comprising a layered double hydroxide and/or an amorphous composite hydroxide containing divalent iron ions, trivalent metal ions and anions.

Section 2. Item 2. The heterogeneous Fenton reaction catalyst according to Item 1, wherein the trivalent metal ion is a trivalent metal ion other than iron ion.

Item 3. Item 3. The heterogeneous Fenton reaction catalyst according to Item 1 or 2, wherein the trivalent metal ion is at least one selected from the group consisting of trivalent aluminum ions, trivalent vanadium ions, and trivalent cerium ions.

Section 4. Item 4. The heterogeneous Fenton reaction catalyst according to any one of Items 1 to 3, wherein the trivalent metal ion is a trivalent aluminum ion.

Item 5. Item 5. The heterogeneous Fenton reaction catalyst according to any one of Items 1 to 4, wherein the anion is an anion of a strong acid.

Item 6. Item 6. The heterogeneous Fenton reaction catalyst according to any one of Items 1 to 5, wherein the anion is at least one selected from the group consisting of sulfate ions, nitrate ions, and halogen ions.

Item 7. The molar ratio of the divalent iron ions and the trivalent metal ions in the layered double hydroxide and/or the amorphous composite hydroxide (divalent iron ions: trivalent metal ions) is 2:1 to 4. 7. The heterogeneous Fenton reaction catalyst according to any one of Items 1 to 6, wherein the heterogeneous Fenton reaction catalyst is 1.

Item 8. 8. Producing the heterogeneous Fenton reaction catalyst according to any one of Items 1 to 7, comprising hydrothermally treating an aqueous solution containing a salt of a divalent iron ion and an anion and a salt of a trivalent metal ion and an anion. how to.

Item 9. Item 8. A method for generating radicals, comprising contacting the heterogeneous Fenton reaction catalyst according to any one of items 1 to 7 with hydrogen peroxide.

Item 10. Contacting the heterogeneous Fenton reaction catalyst according to any one of Items 1 to 7 with hydrogen peroxide to generate radicals, and contacting the radicals with an organic substance;
A method for decomposing organic matter, comprising:

According to the present invention, a heterogeneous Fenton reaction catalyst can be provided. Also, in a preferred form, it is possible to provide a catalyst capable of a heterogeneous Fenton reaction with an efficiency comparable to or exceeding that of the homogeneous Fenton reaction.

According to the present invention, it is also possible to provide a method for generating radicals, a method for decomposing organic substances, etc., using a heterogeneous Fenton reaction catalyst.

1 shows the results of organic matter decomposition test 1 of Test Example 1. FIG. The vertical axis indicates phenol conversion. The horizontal axis indicates the type of sample. Without indicates the case where the sample is not added. LDH stands for Layered Double Hydroxide (the same applies hereinafter). 2 shows the results of organic matter decomposition test 2 of Test Example 2. FIG. The vertical axis indicates phenol conversion. The horizontal axis indicates the type of salt added to the reaction solution (aqueous suspension). Without indicates the case where no salt is added. 3 shows the results of organic matter decomposition test 3 of Test Example 3. FIG. The vertical axis indicates conversion to _CO2 (scale on the left) for bar graphs and phenol conversion (scale on right) for line graphs. The horizontal axis indicates the type of salt added to the reaction solution (aqueous suspension). Without indicates the case where no salt is added. 4 shows the results of organic matter decomposition test 4 of Test Example 4. FIG. The vertical axis indicates conversion to _CO2 (scale on the left) for bar graphs and phenol conversion (scale on right) for line graphs. The horizontal axis indicates the type of sample. In the upper part of the graph, Heterogeneous indicates a heterogeneous reaction system, and Homogeneous indicates a homogeneous reaction system. 5 shows the results of organic matter decomposition test 5 of Test Example 5. FIG. The horizontal axis indicates the conversion rate to _CO2 . The vertical axis indicates the type of sample. 6 shows the results of organic matter decomposition test 6 of Test Example 6. FIG. The horizontal axis indicates the conversion rate to _CO2 . The vertical axis indicates the pH during preparation of the layered double hydroxide.

As used herein, the expressions "contain" and "include" include the concepts "contain", "include", "consist essentially of" and "consist only of".

As used herein, “and/or” is a term that includes both “and” and “or”. That is, A and/or B includes the three meanings of A only, B only, and A and B.

1. In one aspect of the catalyst of the present invention, a layered double hydroxide containing divalent iron ions, trivalent metal ions, and anions (also referred to herein as the "layered double hydroxide of the present invention") ) and/or a heterogeneous Fenton reaction catalyst (in this specification, sometimes referred to as "the catalyst of the present invention") containing an amorphous composite hydroxide. This will be explained below.

The trivalent metal ion is not particularly limited as long as it can form a layered double hydroxide together with the divalent iron ion. Examples of trivalent metal ions include trivalent aluminum ions, trivalent vanadium ions, trivalent cerium ions, trivalent lanthanide ions represented by trivalent lanthanum, trivalent iron ions, trivalent chromium ions, and trivalent cobalt ions. , trivalent indium ion, trivalent gallium ion, trivalent scandium ion, trivalent yttrium ion, trivalent manganese, trivalent arsenic, trivalent molybdenum, trivalent ruthenium, trivalent rhodium, trivalent antimony, trivalent gold, 3 bismuth and the like. Among these, from the viewpoint of activity as a heterogeneous Fenton reaction catalyst, in one embodiment, trivalent metal ions other than iron ions are preferred, and more preferably trivalent aluminum ions, trivalent vanadium ions, trivalent vanadium ions, Examples include lanthanide ions (preferably trivalent cerium ions), more preferably trivalent aluminum ions and trivalent vanadium ions, and particularly preferably trivalent aluminum ions. From the same point of view, in another aspect, trivalent aluminum ions, trivalent gallium ions, trivalent indium ions, etc. are preferred, and trivalent aluminum ions are particularly preferred.

Trivalent metal ions may be used alone or in combination of two or more.

The molar ratio of divalent iron ions and trivalent metal ions (divalent iron ions: trivalent metal ions) in the layered double hydroxide of the present invention is as long as it is a molar ratio capable of forming a layered double hydroxide. There are no particular restrictions. The molar ratio is for example 2:1 to 4:1, preferably 2:1 to 3:1. By increasing the number of moles of trivalent metal ions to divalent iron ions, more anions can be retained.

The anion is not particularly limited as long as it can form a layered double hydroxide. Examples of anions include sulfate ion, nitrate ion, halogen ion (fluoride ion, chloride ion, bromide ion, iodide ion, etc. (preferably chloride ion)), chlorate ion, bromate ion, iodate ion, and perchlorate ion. , anions of strong acids such as perbromate ions; and anions of weak acids such as carbonate ions, hydrogen carbonate ions, phosphate ions, hydrogen phosphate ions, and carboxylate ions (such as acetate ions). Among these, from the viewpoint of activity as a heterogeneous Fenton reaction catalyst, anions of strong acids are preferred. Ions and the like are more preferred, and sulfate ions are even more preferred.

The anion may be used singly or in combination of two or more.

The number of moles of anions in the layered double hydroxide of the present invention can take an appropriate value depending on the number of moles of trivalent metal ions to divalent iron ions and the valence of the anions. Typically, when the number of moles of trivalent metal ions is defined as X and the number of valences of anions is defined as N, the number of moles of anions is X/N.

Although not wishing to be interpreted as limiting, when the catalyst of the present invention is brought into contact with hydrogen peroxide, the peroxide species produced by the reaction between the anion and hydrogen peroxide is It greatly contributes to the Fenton reaction on ferric ions, and combined with the structure of the layered double hydroxide (it is thought that the ferrous ions and anions are arranged close to each other), the efficiency of the Fenton reaction is enhanced. expected to rise.

The mode of arrangement of divalent iron ions, trivalent metal ions, and anions is not particularly limited, and any mode of arrangement that constitutes a layered double hydroxide can be adopted. A layered double hydroxide has a structure in which a basic layer containing hydroxide and an intermediate layer containing anions and interlayer water are alternately laminated. and trivalent metal ions are located in the base layer and anions are located in the intermediate layer. The crystal structure of the basic layer is not particularly limited, and any crystal structure can be adopted according to the types of divalent iron ions and trivalent metal ions, the synthesis method, and the like. The layered double hydroxide is an amorphous composite hydroxide in which divalent iron ions, trivalent metal ions, and anions are arranged close to each other even after the layered structure is destroyed by a calcination treatment, a chemical reaction, or the like. things are formed.

In one aspect, the layered double hydroxide of the present invention typically has the general formula (A): [Fe ²⁺ _1-x M ³⁺ _x (OH) ₂ ][A ^n- _x/n yH ₂ O]. wherein M ³⁺ is a trivalent metal ion, A ⁿ⁻ is an n-valent anion, x is 0<x<1, and y is a real number greater than 0.

The particle shape of the layered double hydroxide of the present invention is not particularly limited. Examples of the particle shape include plate-like, spherical, rod-like, and polyhedral shapes.

The average particle size of the layered double hydroxide of the present invention is not particularly limited. Smaller particles are desirable from the viewpoint of Fenton reaction efficiency. The average particle size is, for example, 10 nm to 5000 nm.

The catalyst of the present invention may consist solely of the layered double hydroxide of the present invention, or may contain other substances. Other substances include, for example, impurities that are unavoidably mixed in when producing the layered double hydroxide of the present invention, other inorganic substances, and amorphous substances obtained after the structure of the layered double hydroxide collapses. Composite hydroxide etc. are mentioned. Other substances may be integrated with the layered double hydroxide of the present invention or separated from the layered double hydroxide of the present invention.

The content of the layered double hydroxide of the present invention is, for example, 50% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more with respect to 100% by mass of the catalyst of the present invention. be. The upper limit of the content is, for example, 99.9% by mass, 99% by mass, and 97% by mass.

By bringing the catalyst of the present invention into contact with hydrogen peroxide, radicals can be generated and organic substances can be decomposed by the radicals. Therefore, the catalyst of the present invention (or the layered double hydroxide of the present invention) is a radical-generating catalyst, a radical-generating ability-imparting agent, a radical-generating ability-enhancing agent, an organic substance decomposition catalyst, an organic substance-decomposing agent, and an organic substance-decomposing agent. It can also be used as an agent or the like.

2. Manufacturing Method The catalyst of the present invention can be manufactured by various methods. For example, it can be produced according to or according to a known method for producing a layered double hydroxide.

The catalyst of the present invention is preferably produced by a method comprising hydrothermally treating an aqueous solution (reaction solution) containing a salt of a divalent iron ion and an anion and a salt of a trivalent metal ion and an anion. be able to.

The bivalent iron ions, trivalent metal ions, and anions are the same as those in "1. Catalyst" above.

The salt of a divalent iron ion and an anion (divalent iron salt) varies depending on the type of anion employed in the layered double hydroxide of the present invention, but for example FeCl ₂ , FeF ₂ , FeBr ₂ and FeI ₂ , FeSO ₄ , Fe(NO ₃ ) ₂ and the like.

The concentration of the bivalent iron salt in the reaction solution is not particularly limited, but is, for example, 0.2 mM to 2000 mM, preferably 20 mM to 200 mM.

Examples of the salt of a trivalent metal ion and an anion (trivalent metal salt) include AlCl _{3 , AlF 3} , AlBr _{3 and} AlI ₃ , depending on the type of anion employed in the layered double hydroxide of the present invention. , _Al2 ( _SO4 ) ₃ , Al( _NO3 ) ₃ , VCl3, _VF3 , _{VBr3 , VI3 , V2} (SO4) ₃ , V( _NO3 ) ₃ , CeCl3, _{CeF3 ,} CeBr ₃ , _CeI3 , _Ce2 ( _SO4 ) ₃ , Ce( _NO3 ) ₃ , FeCl3 _{, FeF3} , _FeBr3 , _FeI3 , _Fe2 ( _SO4 ) ₃ , Fe( _NO3 ) _3, etc. .

The concentration of the trivalent metal salt in the reaction solution is not particularly limited, but is, for example, 0.1 mM to 1000 mM, preferably 10 mM to 100 mM.

The molar ratio of divalent iron and trivalent metal (divalent iron: trivalent metal) is not particularly limited as long as it is a molar ratio that allows synthesizing a layered double hydroxide by hydrothermal treatment. The molar ratio is for example 2:1 to 4:1, preferably 2:1 to 3:1.

The pH of the reaction solution is not particularly limited as long as it is a pH at which a layered double hydroxide can be synthesized by hydrothermal treatment. The pH is for example 2-14, preferably 7-14.

The solvent for the reaction solution is not particularly limited as long as it contains water. Solvents other than water may be included as solvents. The content of water is, for example, 70% by mass or more, 80% by mass or more, 90% by mass or more, 95% by mass or more, or 99% by mass or more with respect to 100% by mass of the solvent in the reaction solution.

The temperature of the hydrothermal treatment is not particularly limited as long as it is a temperature capable of synthesizing the layered double hydroxide. The temperature is for example 20°C to 200°C, preferably 100°C to 120°C.

The reaction time of the hydrothermal treatment is not particularly limited as long as it is a time for generating a certain amount of layered double hydroxide. The reaction time is, for example, 1 h to 100 h, preferably 20 h to 72 h.

The obtained substance can be used as the catalyst of the present invention as it is or mixed with other substances after washing as necessary.

Moreover, if necessary, it can be confirmed that a layered double hydroxide is contained according to or according to a known method. For example, a powder X-ray diffraction pattern can be obtained to determine whether or not layered double hydroxide peaks are included.

3. Method of Utilization In one aspect, the present invention relates to a method for generating radicals, comprising contacting the catalyst of the present invention with hydrogen peroxide. In one aspect, the present invention relates to a method for decomposing organic matter, comprising contacting the catalyst of the present invention with hydrogen peroxide to generate radicals, and contacting the radicals with an organic matter. These are described below.

The mode of contact between the catalyst of the present invention and hydrogen peroxide is not particularly limited. The contact can be carried out, for example, by mixing the catalyst of the invention with hydrogen peroxide. Moreover, the contact is usually carried out in the presence of a solvent such as water. The contacting can be carried out, for example, in a suspension of the catalyst of the invention containing hydrogen peroxide. The concentration of the catalyst of the present invention in the suspension is not particularly limited, and is, for example, 0.001-10% by mass, preferably 0.01-2% by mass, more preferably 0.05-0.5% by mass. The concentration of hydrogen peroxide in the suspension before reaction is not particularly limited, and is, for example, 0.1 to 500 mM, preferably 1 to 200 mM, more preferably 10 to 100 mM.

The mode of contact between the radical and the organic substance is not particularly limited. The contact can be carried out, for example, by mixing the catalyst of the present invention, hydrogen peroxide and an organic substance. Moreover, the contact is usually carried out in the presence of a solvent such as water. The contact can be carried out, for example, in a suspension of the catalyst of the invention containing hydrogen peroxide and organics. The concentration of the catalyst of the present invention in the suspension and the concentration of hydrogen peroxide before the reaction are the same as above. The concentration of the organic substance in the suspension is not particularly limited, and is, for example, 0.001-1000 mM, preferably 0.01-100 mM, more preferably 0.1-10 mM.

The temperature during the contact is not particularly limited as long as it is a temperature at which the Fenton reaction proceeds. The temperature is, for example, 0-100°C, preferably 10-50°C, more preferably 15-40°C.

The contact time is not particularly limited as long as it is a time for generating a certain amount of radicals. The time is, for example, 1 minute to 3 hours, preferably 30 minutes to 2 hours.

Radicals generated by contacting the catalyst of the present invention with hydrogen peroxide are not particularly limited, but are expected to be mainly hydroxyl radicals.

The organic matter to be brought into contact with radicals is not particularly limited as long as it is decomposed by radicals. Examples of such organic substances include organic aliphatic substances, organic aromatic substances, dioxin contaminants, and the like.

Aliphatic substances can be cyclic, acyclic, saturated or unsaturated hydrocarbons. These hydrocarbons are cyclic or acyclic alkanes and alkenes, preferably chlorinated, halogenated cyclic or acyclic alkanes and alkenes, saturated and/or unsaturated aliphatic and/or cycloaliphatic Formula ethers, preferably chlorinated, saturated and/or unsaturated halogenated aliphatic and/or cycloaliphatic ethers, alcohols and preferably chlorinated halogenated alcohols, ketones and preferably chlorinated Halogenated ketones, aldehydes and preferably chlorinated halogenated aldehydes and/or carboxylic acids and preferably chlorinated halogenated carboxylic acids.

Aliphatic substances are preferably trichloropropane, preferably 1,2,3-trichloropropane, chloropropenol, preferably 2-chloro-2-propen-1-ol, dichloropropene, preferably 1,3-dichloropropene cis and 1,3-dichloropropene trans, dichloropropane, preferably 1,3-dichloropropane, dichloropropanol, preferably 1,3-dichloro-2-propanol and 2,3-dichloro-1-propanol, Monochloropropanediol, more preferably 2-chloro-1,3-propanediol and 3-chloro-1,2-propanediol, 2-chloro-1-propanol, 1-chloro-2-propanol, chloroethanol, chloroether , _more preferably _{chloroethers , acrolein} , _{methylglycidyl} ethers _{of the approximate formulas C6H10Cl2O2 , C6H12Cl2O} , _{C6H9Cl3O2 , C6H11Cl3O2} , chloroacetone, methanol, glycerol, ethylene glycol, propylene glycol, butane-1,2-diol, hydroxyacetone, glyceraldehyde, formaldehyde, acetaldehyde, acrolein, formic acid, glycolic acid, acetic acid, propionic acid, lactic acid, succinic acid, selected from oxalic acid, dichloroacetic acid, glycidol, epichlorohydrin, ethylene oxide, propylene oxide, butylene oxide and mixtures thereof.

Aromatics contain at least one ring of aromatic character. They are preferably halogenated aromatic hydrocarbons containing at least one ring of aromaticity and one halogen atom. Halogen may be selected from fluorine, chlorine, bromine, iodine, preferably chlorine. The aromatic ring may be mononuclear or polynuclear, preferably mononuclear. Aromatic substances are preferably selected from mono-, di-, tri-, tetra-, penta- and hexachlorobenzenes and/or naphthalenes and mixtures thereof. The aromatic substance is preferably monochlorobenzene. The aromatic substance may also be oxygenated, such as phenol, mono- and polychlorophenols, preferably phenol.

Dioxin contaminants include, for example, halogenated dibenzodioxins, halogenated dibenzofurans, PCBs (in particular, coplanar PCBs in which chlorine atoms are substituted at positions other than the ortho position), and the like.

Examples of halogenated dibenzodioxins include 2,3,7,8-tetrachlorodibenzo-p-dioxin, 1,2,3,7,8-pentachlorodibenzo-p-dioxin, 1,2,3, 4,7,8-hexachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, 1,2,3,4,6,7,8,9 - Octachlorodibenzo-P-dioxin and the like.

Examples of halogenated dibenzofurans include 2,3,7,8-tetrachlorodibenzofuran, 1,2,3,7,8-pentachlorodibenzofuran, 1,2,3,4,7,8-hexachlorodibenzofuran, 1,2,3,4,6,7,8-heptachlorodibenzofuran, 1,2,3,4,6,7,8,9-octachlorodibenzofuran and the like.

Examples of PCBs (especially coplanar PCBs with chlorine atoms substituted at positions other than the ortho position) include 3,3',4,4',5-tetrachlorobiphenyl, 3,3',4,4',5 -pentachlorobiphenyl, 3,3',4,4',5,5'-hexachlorobiphenyl and the like.

EXAMPLES The present invention will be described in detail below based on examples, but the present invention is not limited by these examples.

Example 1: Preparation of Cl ^- type Fe(II)-Al(III)-layered double hydroxide 1
An aqueous solution containing _FeCl2 and _AlCl3 (molar ratio (Fe:Al) = 2:1, _FeCl2 concentration = 200 mM, _AlCl3 concentration = 100 mM, pH = 10 (adjusted with 5M NaOH aqueous solution)) was added to 120 By hydrothermal treatment at ℃ for 24 hours, a layered double hydroxide containing divalent iron ions, trivalent aluminum ions, and chloride ions (Cl ^-type Fe(II)-Al(III)-layered double hydroxide ) was prepared. The obtained layered double hydroxide was observed by SEM and confirmed to have a particle size of 10 nm to 5000 nm. In addition, powder X-ray diffraction (XRD) was performed, and it was confirmed that a layered double hydroxide peak was present in the XRD pattern.

Example 2: Preparation of SO ₄ ^2- type Fe(II)-Al(III)-layered double hydroxide
Aqueous solution containing _FeSO4 and _Al2 ( _SO4 ) ₃ (molar ratio (Fe:Al) = 2:1, _FeSO4 concentration = 200 mM, _Al2 ( _SO4 ) ₃ concentration = 100 mM, pH = 10 ( A layered double hydroxide containing divalent iron ions, trivalent aluminum ions and sulfate ions (SO ₄ ^2- type Fe(II )-Al(III)-layered double hydroxide) were prepared. The obtained layered double hydroxide was observed by SEM and confirmed to have a particle size of 10 nm to 5000 nm. In addition, powder X-ray diffraction (XRD) was performed, and it was confirmed that a layered double hydroxide peak was present in the XRD pattern.

Example 3: Preparation of Cl ^-type Fe(II)-V(III)-layered double hydroxide
An aqueous solution containing _FeCl2 and _VCl3 (molar ratio (Fe:V) = 2:1, _FeCl2 concentration = 200 mM, _VCl3 concentration = 100 mM, pH = 10 (adjusted with 5M NaOH aqueous solution)) was added to 120 By hydrothermal treatment at ℃ for 24 hours, a layered double hydroxide containing divalent iron ions, trivalent vanadium ions, and chloride ions (Cl ^-type Fe(II)-V(III)-layered double hydroxide ) was prepared. Moreover, powder X-ray diffraction (XRD) was performed on the obtained layered double hydroxide, and it was confirmed that a peak of the layered double hydroxide was present in the XRD pattern.

Example 4: Preparation of Cl ^- type Fe(II)-Ce(III)-layered double hydroxide
An aqueous solution containing _FeCl2 and _CeCl3 (molar ratio (Fe:Ce) = 2:1, _FeCl2 concentration = 200 mM, _VCl3 concentration = 100 mM, pH = 10 (adjusted with 5M NaOH aqueous solution)) was added to 120 By hydrothermal treatment at ℃ for 24 hours, a layered double hydroxide containing divalent iron ions, trivalent cerium ions, and chloride ions (Cl ^-type Fe(II)-Ce(III)-layered double hydroxide ) was prepared.

Example 5: Preparation of Cl ^-type Fe(II)-Fe(III)-layered double hydroxide
Aqueous solution containing _FeCl2 and _FeCl3 (molar ratio (Fe(II):Fe(III)) = 2:1, _FeCl2 concentration = 200 mM, _FeCl3 concentration = 100 mM, pH = 10 (5M NaOH aqueous solution A layered double hydroxide containing divalent iron ions, trivalent iron ions, and chloride ions (Cl ^-type Fe(II)-Fe(III) - layered double hydroxides) were prepared.

Example 6: Preparation of Cl ^- type Fe(II)-Al(III)-layered double hydroxide 2
A Cl ₂ ^-type Fe(II)-Al(III)-layered double hydroxide was prepared in the same manner as in Example 1 except that the pH of the aqueous solution containing FeCl 2 and AlCl ₃ was 7. Moreover, powder X-ray diffraction (XRD) was performed on the obtained layered double hydroxide, and it was confirmed that a peak of the layered double hydroxide was present in the XRD pattern.

Example 7: Preparation of Cl ^- type Fe(II)-Al(III)-layered double hydroxide 3
A Cl 2 ^-type Fe(II)-Al(III)-layered double hydroxide was prepared in the same manner as in Example 1, except that the pH of the aqueous solution containing FeCl ₂ and AlCl ₃ was 11. Moreover, powder X-ray diffraction (XRD) was performed on the obtained layered double hydroxide, and it was confirmed that a peak of the layered double hydroxide was present in the XRD pattern.

Comparative Example 1: Preparation of Cl -type Mg(II)-Fe(III)-layered double ^hydroxide
An aqueous solution containing _MgCl2 and _FeCl3 (molar ratio (Mg:Fe) = 2:1, _MgCl2 concentration = 200 mM, _FeCl3 concentration = 100 mM, pH = 10 (adjusted with 5M NaOH aqueous solution)) was added to 120 ℃ for 24 hours, a layered double hydroxide containing divalent magnesium ions, trivalent iron ions, and chloride ions (Cl ^-type Mg(II)-Fe(III)-layered double hydroxide ) was prepared.

Comparative Example 2: Preparation of Cl ^-type Mg(II)-Al(III)-layered double hydroxide
An aqueous solution containing _MgCl2 and _AlCl3 (molar ratio (Mg:Al) = 2:1, _MgCl2 concentration = 200 mM, _AlCl3 concentration = 100 mM, pH = 10 (adjusted with 5M NaOH aqueous solution)) was added to 120 By hydrothermal treatment at ℃ for 24 hours, a layered double hydroxide containing divalent magnesium ions, trivalent aluminum ions, and chloride ions (Cl-type Mg(II)-Al(III)-layered double hydroxide ) was prepared.

Comparative Example 3: Preparation of Cl ^-type Co(II)-Fe(III)-layered double hydroxide
An aqueous solution containing _CoCl2 and _FeCl3 (molar ratio (Co:Fe) = 2:1, _CoCl2 concentration = 200 mM, _FeCl3 concentration = 100 mM, pH = 10 (adjusted with 5M NaOH aqueous solution)) was added to 120 ℃ for 24 hours, a layered double hydroxide containing divalent cobalt ions, trivalent iron ions, and chloride ions (Cl ^-type Co(II)-Fe(III)-layered double hydroxide ) was prepared. Moreover, powder X-ray diffraction (XRD) was performed on the obtained layered double hydroxide, and it was confirmed that a peak of the layered double hydroxide was present in the XRD pattern.

Comparative Example 4: Preparation of Cl ^-type Co(II)-Al(III)-layered double hydroxide
An aqueous solution containing _CoCl2 and _AlCl3 (molar ratio (Co:Al) = 2:1, _CoCl2 concentration = 200 mM, _AlCl3 concentration = 100 mM, pH = 10 (adjusted with 5M NaOH aqueous solution)) was added to 120 ℃ for 24 hours, layered double hydroxide containing divalent cobalt ions, trivalent aluminum ions, and chloride ions (Cl ^-type Co(II)-Al(III)-layered double hydroxide ) was prepared. Moreover, powder X-ray diffraction (XRD) was performed on the obtained layered double hydroxide, and it was confirmed that a peak of the layered double hydroxide was present in the XRD pattern.

Comparative Example 5: Preparation of Cl ^-type Mn(II)-Fe(III)-layered double hydroxide
An aqueous solution containing _MnCl2 and _FeCl3 (molar ratio (Mn:Fe) = 2:1, _MnCl2 concentration = 200 mM, _FeCl3 concentration = 100 mM, pH = 10 (adjusted with 5M NaOH aqueous solution)) was added to 120 ℃ for 24 hours, a layered double hydroxide containing divalent manganese ions, trivalent iron ions, and chloride ions (Cl ^-type Mn(II)-Fe(III)-layered double hydroxide ) was prepared.

Comparative Example 6: Preparation of Cl -type Cu(II)-Fe(III)-layered double ^hydroxide
An aqueous solution containing _CuCl2 and _FeCl3 (molar ratio (Cu:Fe) = 2:1, _CuCl2 concentration = 200 mM, _FeCl3 concentration = 100 mM, pH = 10 (adjusted with 5M NaOH aqueous solution)) was added to 120 By hydrothermal treatment at ℃ for 24 hours, a layered double hydroxide containing divalent copper ions, trivalent iron ions, and chloride ions (Cl ^-type Cu(II)-Fe(III)-layered double hydroxide ) was prepared.

Test example 1: Organic matter decomposition test 1
Sample (Example 1, Comparative Example 1, Comparative Example 2, Comparative Example 4, FeO, or α-FeOOH) (30 mg) in water suspension (heterogeneous) (20 mL), phenol (20 μmol) and H ₂ O ₂ (600 μmol) were added, and the mixture was stirred at 30° C. for 60 minutes to react. The amount of phenol after the reaction was quantified by gas chromatography. Based on the quantitative value, the phenol conversion rate (= [(amount of phenol before reaction (20 µmol) - quantitative value of phenol after reaction (unit: µmol))/amount of phenol before reaction (20 µmol)] x 100) was calculated. .

The results are shown in FIG. It was found that the layered double hydroxide (FeAl-LDH) containing divalent iron ions, trivalent metal ions and anions promotes the decomposition reaction of phenol. From this, it was found that the layered double hydroxide promotes radical generation as a heterogeneous Fenton reaction catalyst, thereby decomposing phenol. In addition, the degree of phenol decomposition when using the layered double hydroxide is much higher than when iron oxides containing iron (FeO, α-FeOOH) are used, so the layered double hydroxide was found to be remarkably excellent in activity as a heterogeneous Fenton reaction catalyst.

Test example 2: Organic matter decomposition test 2
Aqueous suspension (heterogeneous) (20 mL) containing sample (Example 1) (30 mg), or salt that produces sample (Example 1) (30 mg) and various inorganic anions (12 mmol) ( NaCl, Na ₂ SO ₄ , NaNO ₃ , Na ₂ HPO ₄ , NaHCO ₃ , or Na ₂ CO ₃ ) in water suspension (heterogeneous) (20 mL), phenol (20 μmol) and H ₂ O ₂ (600 μmol) was added, and the mixture was stirred at 30° C. for 60 minutes to react. When there is a high concentration of inorganic anions in the water suspension, it is expected that the anions in the layered double hydroxide (chloride ions in Example 1) will be replaced by the inorganic anions (the test below same in the example). The phenol conversion rate was calculated in the same manner as in Test Example 1.

The results are shown in FIG. It was found that the activity of layered double hydroxides containing divalent iron ions, trivalent metal ions, and anions as heterogeneous Fenton reaction catalysts is particularly high when the anions of strong acids are used as the anions. On the other hand, when a weakly acidic anion was used, the activity against phenol decomposition was weak.

Test example 3: Organic matter decomposition test 3
Aqueous suspension (heterogeneous) (20 mL) containing sample (Example 1) (30 mg), or salt that produces sample (Example 1) (30 mg) and various inorganic anions (12 mmol) ( Phenol (20 μmol) and H ₂ O ₂ (600 μmol) were added to an aqueous suspension (heterogeneous) (20 mL) containing NaCl, Na ₂ SO ₄ , or NaNO ₃ ) and stirred at 30°C for 60 minutes. reacted with The phenol conversion rate was calculated in the same manner as in Test Example 1. In addition, the amount of CO ₂ generated by the reaction was quantified by gas chromatography, and based on the quantitative value, the conversion rate to CO ₂ (= [CO ₂ quantitative value after reaction (unit: μmol) / (6 × before reaction The amount of phenol (20 μmol))] × 100) was calculated.

The results are shown in FIG. From the _CO2 conversion results, the activity of layered double hydroxides containing divalent iron ions, trivalent metal ions, and anions as heterogeneous Fenton reaction catalysts varies with the type of anions of strong acids. I found out.

Test example 4: Organic matter decomposition test 4
Aqueous suspension (heterogeneous system) (20 mL) containing sample (Example 1 or Example 2) (30 mg), or aqueous solution (homogeneous system) containing sample (FeSO ₄ ) (0.22 mmol) (20 mL), phenol (20 μmol) and H ₂ O ₂ (600 μmol) were added, and the mixture was stirred at 30° C. for 60 minutes to react. The phenol conversion rate was calculated in the same manner as in Test Example 1, and the conversion rate to CO ₂ was calculated in the same manner as in Test Example 3.

The results are shown in FIG. The heterogeneous Fenton reaction using layered double hydroxides containing divalent iron ions, trivalent metal ions, and anions in this study was found to be more efficient than the homogeneous Fenton reaction.

Test example 5: Organic matter decomposition test 5
Sample (Example 1, Example 3, Example 4, Example 5, Comparative Example 1, Comparative Example 3, Comparative Example 5, Comparative Example 6) (30 mg) containing water suspension (heterogeneous) ( 20 mL), phenol (20 μmol) and H ₂ O ₂ (600 μmol) were added, and the mixture was stirred at 30° C. for 60 minutes to react.

The results are shown in FIG. It was found that the activity of layered double hydroxides containing divalent iron ions, trivalent metal ions, and anions as heterogeneous Fenton reaction catalysts varies with the type of trivalent metal ions. It was found that when trivalent metal ions other than iron ions (especially aluminum ions, vanadium ions, cerium ions, especially aluminum ions) were used as the trivalent metal ions, the activity was high.

Test example 6: Organic matter decomposition test 6
Phenol (20 µmol) and H ₂ O ₂ (600 µmol) were added to an aqueous suspension (heterogeneous system) (20 mL) containing a sample (Example 1, Example 6, or Example 7) (30 mg). , and stirred at 30° C. for 15 minutes to react.

The results are shown in FIG. It was found that the activity was somewhat affected by the pH when hydrothermal treatment was used to obtain layered double hydroxides containing divalent iron ions, trivalent metal ions, and anions.

Claims (9)

from the group comprising layered double hydroxides containing divalent iron ions, trivalent metal ions, and anions, and wherein the trivalent metal ions consist of trivalent aluminum ions, trivalent vanadium ions, and trivalent cerium ions; At least one selected heterogeneous Fenton reaction catalyst. 2. The heterogeneous Fenton reaction catalyst according to claim 1, wherein said trivalent metal ions are trivalent metal ions other than iron ions. 3. The heterogeneous Fenton reaction catalyst according to claim 1 or 2 , wherein said trivalent metal ion is trivalent aluminum ion. The heterogeneous Fenton reaction catalyst according to any one of claims 1 to 3 , wherein said anion is an anion of a strong acid. 5. The heterogeneous Fenton reaction catalyst according to any one of claims 1 to 4 , wherein said anion is at least one selected from the group consisting of sulfate ions, nitrate ions and halogen ions. Claims 1 to 5, wherein the molar ratio of the divalent iron ions to the trivalent metal ions in the layered double hydroxide (divalent iron ions: trivalent metal ions) is 2:1 to 4: 1 . The heterogeneous Fenton reaction catalyst according to any one of . The heterogeneous Fenton reaction catalyst according to any one of claims 1 to 6 , which comprises hydrothermally treating an aqueous solution containing a salt of a divalent iron ion and an anion and a salt of a trivalent metal ion and an anion. How to manufacture. A method for generating radicals, comprising contacting the heterogeneous Fenton reaction catalyst according to any one of claims 1 to 6 with hydrogen peroxide. Contacting the heterogeneous Fenton reaction catalyst according to any one of claims 1 to 6 with hydrogen peroxide to generate radicals, and contacting the radicals with an organic substance;
A method for decomposing organic matter, comprising:

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