JP2005177590A - Treatment method for oxidizing component-containing water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a handling operability in the case of supplying hydrogen gas required for reaction by using a high-safety hydrogen gas supply source in place of high-pressure hydrogen gas when performing the catalytic decomposition by adding hydrogen gas to water containing dissolved oxygen and an oxidizing component such as nitrate. <P>SOLUTION: In the method for treating oxidizing component containing water, hydrogen gas is added to the oxidizing component-containing water and is reacted with the oxidizing component-containing water in the presence of a catalyst to decompose and remove the oxidizing component. Therein, an organic compound which stores hydrogen gas is used as the hydrogen gas supply source and hydrogen gas released from the hydrogen storage organic compound is added to the oxidizing component-containing water. The organic compound can stably store hydrogen gas in a relatively lightweight state and at a nearly normal temperature and pressure as a hydrogen molecule compound or the like and, moreover, can release the stored hydrogen. Accordingly, by using the organic compound that stores hydrogen as the hydrogen gas supply source for hydrogen gas reduction catalytic decomposition of various kinds of oxidizing component-containing water, the handling operability of hydrogen gas is drastically enhanced and the treatment of the oxidizing component-containing water can be safely performed under an excellent operation environment. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a treatment method for oxidizing component-containing water in which hydrogen gas is added to water containing an oxidizing component such as dissolved oxygen and nitrate to perform catalytic decomposition, and in particular, a highly safe hydrogen gas supply source is used. Thus, the present invention relates to a method for treating water containing an oxidizing component, which improves the handling workability of hydrogen gas necessary for the reaction.

  Normally, soft water is used for boiler water supply, but since the soft water contains dissolved oxygen, the water supply causes oxidative corrosion of the heat exchanger and economizer in the boiler body, the front stage of the boiler body. For this reason, it is necessary to deoxidize the boiler feed water before supplying it to the boiler.

  Conventionally, as a deoxygenation treatment method for water, a method using hydrazine and sodium sulfite as a deoxygenating agent has been widely adopted. However, hydrazine has a problem in terms of safety, and sodium sulfite reacts with oxygen. Since the rate is too high, it reacts with dissolved oxygen in the dissolution tank to cause a decrease in concentration, so that there is a problem that the injection amount becomes insufficient and corrosion is promoted.

  Therefore, as a deoxygenation method for solving such a problem, there is a method in which hydrogen gas is added to water containing dissolved oxygen and then contacted with a catalyst carrying a metal component having catalytic ability at a temperature lower than 100 ° C. Proposed (JP-A-6-39380). In this method, since a supported catalyst having catalytic ability at a temperature lower than 100 ° C. is used, hydrogen gas corresponding to the dissolved oxygen concentration in the water to be treated coexists in the presence of the supported catalyst, and the temperature is lower than 100 ° C. It is possible to effectively remove the dissolved oxygen by allowing the deoxygenation reaction to proceed effectively.

On the other hand, as a method for treating nitrate-containing water, it has been proposed to inject hydrogen gas into this water and then contact the palladium catalyst or rhodium catalyst to reduce nitrate to nitrogen (Japanese Patent Laid-Open No. 2-111495). Publication). That is, when hydrogen gas is added to wastewater containing nitrate such as NH ₄ NO ₃ and heated to a predetermined temperature and brought into contact with the catalyst, NH ₄ NO ₃ is decomposed into N ₂ and removed by the following reaction. Can do.
NH ₄ ⁺ + NO ₃ ⁻ + H ₂ → N 2 + 3H ₂ O

  Further, in this method, as a method for more easily and efficiently treating high-concentration wastewater, a method in which the amount of hydrogen gas added exceeds the solubility of hydrogen gas in this water has been proposed (Japanese Patent Laid-open No. Hei 6-1994). No. 226268). In this method, an excessive amount of hydrogen gas is added, and the above reaction proceeds in a state where hydrogen gas bubbles are present in the catalyst layer. Hydrogen corresponding to the amount shifts from the gas phase to the liquid phase, and dissolved hydrogen is replenished sequentially. For this reason, even if it is high concentration drainage, it becomes possible to decompose efficiently with sufficient supply amount of hydrogen gas.

  Thus, as a method for treating water containing an oxidizable component such as dissolved oxygen or nitrate, that is, a component that can be reduced and decomposed by hydrogen gas as a reducing agent, there is a method of catalytic decomposition by adding hydrogen gas to this water. Many proposals have been made.

  Conventionally, a hydrogen gas supply source used for the treatment of such oxidizing component-containing water is not particularly specified, but generally a high-pressure hydrogen gas cylinder is used.

In addition, the applicant of the present invention is able to store hydrogen relatively lightly and stably in a state close to normal temperature and normal pressure, and as a novel hydrogen storage method for hydrogen that can be easily taken out. A method for storing hydrogen gas as a hydrogen molecular compound or the like in a compound was previously proposed (Japanese Patent Application No. 2003-24590).
JP-A-6-39380 JP-A-2-111495 JP-A-6-226268 Japanese Patent Application No. 2003-24590

  As described above, a high-pressure hydrogen gas cylinder is generally used as a hydrogen gas supply source in hydrogen gas reduction catalytic cracking of conventional oxidizing component-containing water. However, hydrogen gas is an explosive combustible gas, The handling of hydrogen gas in the state required great care based on the response based on the High Pressure Gas Safety Law.

  The present invention solves the above-mentioned conventional problems, and adds hydrogen gas to water containing an oxidizing component such as dissolved oxygen and nitrate to perform catalytic cracking. An object of the present invention is to provide a method for treating oxidizing component-containing water with improved handling workability when supplying hydrogen gas necessary for the reaction by using a supply source.

  The method for treating oxidizing component-containing water of the present invention is a method for treating oxidizing component-containing water in which hydrogen gas is added to the oxidizing component-containing water and reacted in the presence of a catalyst to decompose and remove the oxidizing component. An organic compound storing hydrogen gas is used as a hydrogen gas supply source, and hydrogen gas released from the hydrogen storing organic compound is added to the oxidizing component-containing water.

  An organic compound can be stably stored in a state of relatively light weight and near normal temperature and pressure as a hydrogen molecular compound or the like, and the stored hydrogen can be easily released. Therefore, by using an organic compound storing hydrogen as a hydrogen gas supply source for hydrogen gas reduction catalytic cracking of various oxidizing component-containing water, the handling property of hydrogen gas is remarkably improved, and the treatment of oxidizing component-containing water is performed. It is possible to perform safely under a good working environment.

  In the present invention, the organic compound does not include those composed only of carbon atoms such as graphite, carbon nanotubes, fullerenes, and includes organometallic compounds including a metal component.

  In addition, the molecular compound referred to in the present invention is a relatively weak interaction other than a covalent bond, in which two or more kinds of compounds that can exist stably alone are represented by hydrogen bonds and van der Waals forces. And includes hydrates, solvates, addition compounds, inclusion compounds, and the like. Such a hydrogen molecule compound can be formed by a catalytic reaction under pressure between an organic compound that forms a hydrogen molecule compound and hydrogen, and can store hydrogen in a relatively lightweight state close to normal temperature and pressure. In addition, hydrogen can be released from the hydrogen molecular compound by simple heating or the like.

  Examples of the hydrogen molecule compound according to the present invention include a hydrogen clathrate compound in which a hydrogen molecule is clathrated by a contact reaction between an organic compound and a hydrogen molecule.

  According to the method for treating oxidizing component-containing water of the present invention, by using an organic compound storing hydrogen as a hydrogen gas supply source for hydrogen gas reduction catalytic cracking of various oxidizing component-containing water, Processing can be performed safely under a favorable work environment.

  Hereinafter, embodiments of the method for treating water containing an oxidizing component of the present invention will be described in detail.

  In the present invention, an organic compound that stores hydrogen gas as a hydrogen gas supply source when hydrogen gas is added to the oxidizing component-containing water to catalytically reduce and decompose the oxidizing component in the oxidizing component-containing water in the presence of a catalyst. Is used.

  In the present invention, the oxidizing component to be treated is not particularly limited as long as it is an oxidizing component that is reduced and decomposed by hydrogen gas in the presence of a catalyst, and examples thereof include the dissolved oxygen and nitrate described above. . In addition, since organic halogen compounds such as organic chlorine compounds, which are environmental pollutants contained in groundwater, can be dehalogenated and decomposed by adding hydrogen gas and heating in the presence of a catalyst, the present invention. Can be processed.

  An embodiment in the case of treating nitrate-containing wastewater by the method of the present invention will be described below with reference to FIG.

In FIG. 1, 1 is a wastewater storage tank containing nitrate (in this embodiment, ammonium nitrate (NH ₄ NO ₃ )), 2 is a pump, 3 is a heat exchanger, 4 is a pressure regulating valve, 5 is a heater, and 6 is hydrogen. A hydrogen generator containing a storage organic compound, 7 is a compressor, and 8 is a catalyst tower on which a catalyst layer 8A is formed. Reference numerals 11, 12, 13, 14, 15, and 16 denote pipes.

In the method of FIG. 1, NH ₄ NO ₃ -containing waste water in the storage tank 1 is introduced into the heat exchanger 3 through a pipe 11 provided with a pump 2, and treated water discharged from a catalyst tower 8 described later through a pipe 13. After heat exchange with the heater 5 and further heated by the heater 5, it is introduced into the catalyst tower 8 through the pipe 12 and catalytically decomposed. On the inlet side of the catalyst tower 8, the introduction pipe 12 is connected to the introduction pipe 12 from the hydrogen generator 6 through the pipe 16. Add hydrogen gas. The organic compound of the hydrogen storage organic compound incorporated in the hydrogen generator 6 and the hydrogen releasing method thereof will be described later.

  In the present invention, the hydrogen gas addition amount is preferably an addition amount exceeding the hydrogen gas solubility in the wastewater to be treated, and the hydrogen gas is preferably supplied so that hydrogen bubbles are present in the catalyst layer 8A of the catalyst tower 8. . Such excessive addition of hydrogen gas enables efficient catalytic cracking treatment even for highly concentrated wastewater.

The treated water from which NH ₄ NO ₃ contained in the catalyst tower 8 has been decomposed and removed is withdrawn through the pipe 13, exchanged heat with the wastewater to be treated in the heat exchanger 3, and then discharged out of the system through the pipe 14. Is done.

  On the other hand, a gas component containing surplus hydrogen gas and nitrogen gas generated by the reaction is discharged out of the system through the pipe 15. In addition, you may make it isolate | separate and reuse the hydrogen gas in this waste gas with a hydrogen recovery apparatus provided with a hydrogen separation membrane.

  As a catalyst used for the catalytic reductive decomposition of nitrate, platinum, palladium, ruthenium, rhodium, indium, iridium, silver, gold, cobalt, nickel and tungsten, and water insoluble or poorly water-soluble of these metals are used as catalytic active ingredients. Compounds, specifically, oxides such as cobalt monoxide, nickel monoxide, ruthenium dioxide, rhodium trioxide, palladium monoxide, iridium dioxide and tungsten dioxide, and further chlorides such as ruthenium dichloride and platinum dichloride , One or two or more selected from the group consisting of sulfides such as ruthenium sulfide and rhodium sulfide are supported on a carrier such as alumina, activated carbon, titanium oxide and zirconia oxide. The supported amount of the metal and / or the compound thereof in such a supported catalyst is usually 0.05 to 25% by weight, preferably 0.5 to 3% by weight of the support weight. Such a supported catalyst can be used in various forms such as a spherical shape, a pellet shape, a columnar shape, a crushed piece shape, a honeycomb shape, and a powder shape.

  In the treatment of nitrate-containing wastewater according to the present invention, as shown in FIG. 1, the wastewater containing nitrate is heated, hydrogen gas released from the hydrogen storage organic compound is added, and this is filled with the supported catalyst. It can be carried out by passing the solution through the reaction layer. In this case, it is preferable to set the reaction layer volume, the catalyst filling amount, and the liquid flow rate so that the contact time between the wastewater to be treated and the supported catalyst is 3 to 60 minutes, particularly 10 to 20 minutes. The particle size of the supported catalyst used in the fixed bed type reaction layer is usually about 0.2 to 10 mm, particularly preferably about 0.5 to 5 mm. The decomposition treatment temperature is preferably 85 to 180 ° C, particularly 140 to 170 ° C.

  In addition, when hydrogen gas is excessively added, the addition ratio is appropriately determined depending on the nitrate concentration of the wastewater to be treated, and it is preferable to increase the excessive amount of hydrogen gas as the nitrate concentration increases. Usually, the supply pressure of hydrogen gas is less than 0.1 to 1.0 MPa, and the hydrogen gas is about 1/3 to 100 times the theoretical amount for reducing nitrate in the wastewater to be treated to nitrogen gas. In particular, it is preferable to add so as to be 1/3 to 10 times.

  Next, a method for decomposing and removing dissolved oxygen in water by the method of the present invention will be described.

  In order to perform deoxygenation treatment of dissolved oxygen-containing water by the method of the present invention, hydrogen gas released from a hydrogen storage organic compound is added to the water to be treated as described later, and then contacted with a catalyst carrying a metal component. . Here, although the addition amount of hydrogen gas changes with dissolved oxygen concentration etc. of to-be-processed water, it is preferable to add about 0.03-500 mg / L, especially about 1-50 mg / L in normal cases.

  Further, the deoxygenation catalyst is preferably one that carries a metal component having catalytic ability at a temperature lower than 100 ° C., and the metal component that serves as such a catalyst active component represents a metal and / or a metal compound. . Examples of the metal include iron, cobalt, molybdenum, nickel, ruthenium, palladium, rhodium, iridium, platinum, copper, gold, and tungsten. As the metal compound, a water-insoluble or poorly water-soluble compound of these metals, specifically, iron sesquioxide, iron tetroxide, cobalt monoxide, nickel monoxide, ruthenium dioxide, rhodium sesquioxide, palladium monoxide, One or two selected from the group consisting of oxides such as iridium dioxide, cupric oxide, tungsten dioxide, further, chlorides such as ruthenium dichloride and platinum dichloride, sulfides such as ruthenium sulfide and rhodium sulfide, etc. More than species. In the present invention, palladium and platinum are particularly preferable as the metal component.

  The supported catalyst used for deoxygenation is one in which these metal components are supported on a carrier such as alumina, silica, silica-alumina, activated carbon, carbon, titanium oxide, zirconia, and calcium carbonate according to a conventional method. The supported amount of the metal component in the catalyst is usually 0.05 to 25% by weight, preferably 0.3 to 3% by weight of the carrier weight. Such a supported catalyst can be used in various forms such as a spherical shape, a pellet shape, a columnar shape, a fragmented shape, a honeycomb shape, and a powder shape.

In the deoxygenation treatment according to the present invention, for example, a predetermined amount of hydrogen gas from a hydrogen storage organic compound is added to water containing dissolved oxygen, and this is passed through a fixed bed reaction layer filled with the supported catalyst. Can be implemented. In this case, it is preferable to set the reaction layer volume, the catalyst filling amount, and the liquid flow rate so that the space velocity (SV) is 10 to 500 hr ⁻¹ , particularly 50 to 200 hr ⁻¹ . The particle size of the supported catalyst used in the fixed bed type reaction layer is usually 3 to 50 mm, particularly preferably about 5 to 25 mm.

  The deoxygenation reaction conditions are a reaction temperature of less than 100 ° C., preferably 40 to 80 ° C., and a pressure at which water to be treated can maintain a liquid phase at the reaction temperature. The higher the reaction temperature, the higher the removal rate of dissolved oxygen and the shorter the residence time of the water in the reaction tower, but on the other hand, the equipment cost increases, so the required processing level, operating cost, It may be determined in consideration of construction costs and the like. Moreover, the pressure at the time of reaction should just be a pressure with which to-be-processed water maintains a liquid phase at the minimum predetermined temperature.

In the method of the present invention, an alkaline agent such as sodium hydroxide, sodium carbonate, potassium hydroxide, potassium carbonate or the like or a volatile amine such as alkanolamine such as monoethanolamine, isopropanolamine, cyclohexylamine or the like is added to the reaction system. Coexistence is extremely effective. That is, in the present invention, since CO ₂ is generated by the deoxygenation reaction, corrosion can be prevented by reaction removal with an alkali agent or amines. In this case, the alkali agent or alkanolamine is preferably added in an amount of about 1.0 to 500 mg / L with respect to hydrogen gas.

  Next, the hydrogen storage organic compound used as a hydrogen gas supply source in the present invention will be described.

  In the present invention, the organic compound used for storing hydrogen is an organic compound excluding those consisting only of carbon atoms, and is not particularly limited as long as it can store hydrogen by contacting with hydrogen gas. This organic compound may be one that does not contain a metal component, or may be an organometallic compound that contains a metal component.

  Among the hydrogen molecular compounds, monomolecular, polymolecular, and polymeric host compounds are known as organic compounds that form hydrogen clathrate compounds that include hydrogen molecules.

  Monomolecular host compounds include cyclodextrins, crown ethers, cryptands, cyclophanes, azacyclophanes, calixarenes, cyclotriveratrylenes, spherands, cyclic oligopeptides, etc. . Examples of the multi-molecular host compound include ureas, thioureas, deoxycholic acids, perhydrotriphenylenes, tri-o-thymotides, beansryls, spirobifluorenes, cyclophosphazenes, monoalcohols, Diols, acetylene alcohols, hydroxybenzophenones, phenols, bisphenols, trisphenols, tetrakisphenols, polyphenols, naphthols, bisnaphthols, diphenylmethanols, carboxylic acid amides, thioamides, bixanthenes, Examples thereof include carboxylic acids, imidazoles, and hydroquinones. In addition, examples of the polymer host compound include celluloses, starches, chitins, chitosans, polyvinyl alcohols, polyethylene glycol arm type polymers having 1,1,2,2-tetrakisphenylethane as a core, α, Examples include polyethylene glycol arm type polymers having α, α ′, α′-tetrakisphenylxylene as a core.

  In addition, an organophosphorus compound, an organosilicon compound, etc. are also mentioned.

  Further, some organometallic compounds exhibit properties as host compounds, such as organoaluminum compounds, organotitanium compounds, organoboron compounds, organozinc compounds, organoindium compounds, organogallium compounds, organotellurium compounds, organotin compounds. , Organic zirconium compounds, and organic magnesium compounds. Moreover, it is also possible to use a metal salt of an organic carboxylic acid, an organic metal complex, or the like, but it is not particularly limited as long as it is an organic metal compound.

  Of these host compounds, multi-molecular host compounds whose inclusion ability is hardly influenced by the molecular size of the guest compound are preferable.

  Specific examples of the multimolecular host compound include urea, 1,1,6,6-tetraphenylhexa-2,4-diyne-1,6-diol, and 1,1-bis (2,4-dimethyl). Phenyl) -2-propyn-1-ol, 1,1,4,4-tetraphenyl-2-butyne-1,4-diol, 1,1,6,6-tetrakis (2,4-dimethylphenyl)- 2,4-hexadiyne-1,6-diol, 9,10-diphenyl-9,10-dihydroanthracene-9,10-diol, 9,10-bis (4-methylphenyl) -9,10-dihydroanthracene- 9,10-diol, 1,1,2,2-tetraphenylethane-1,2-diol, 4-methoxyphenol, 2,4-dihydroxybenzophenone, 4,4′-dihydroxybenzophenone, 2 2'-dihydroxybenzophenone, 2,2 ', 4,4'-tetrahydroxybenzophenone, 1,1-bis (4-hydroxyphenyl) cyclohexane, 4,4'-sulfonylbisphenol, 2,2'-methylenebis (4- Methyl-6-tert-butylphenol), 4,4′-ethylidenebisphenol, 4,4′-thiobis (3-methyl-6-tert-butylphenol), 1,1,3-tris (2-methyl-4-hydroxy) -5-t-butylphenyl) butane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethylene, 1,1,2, 2-tetrakis (3-methyl-4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (3-fluoro-4-hydroxy) Phenyl) ethane, α, α, α ′, α′-tetrakis (4-hydroxyphenyl) -p-xylene, tetrakis (p-methoxyphenyl) ethylene, 3,6,3 ′, 6′-tetramethoxy-9, 9'-bi-9H-xanthene, 3,6,3 ', 6'-tetraacetoxy-9,9'-bi-9H-xanthene, 3,6,3', 6'-tetrahydroxy-9,9 ' -Bi-9H-xanthene, gallic acid, methyl gallate, catechin, bis-β-naphthol, α, α, α ′, α′-tetraphenyl-1,1′-biphenyl-2,2′-dimethanol, Diphenic acid bisdicyclohexylamide, fumaric acid bisdicyclohexylamide, cholic acid, deoxycholic acid, 1,1,2,2-tetraphenylethane, tetrakis (p-iodophenyl) ethylene, 9,9 ′ -Beanthryl, 1,1,2,2-tetrakis (4-carboxyphenyl) ethane, 1,1,2,2-tetrakis (3-carboxyphenyl) ethane, acetylenedicarboxylic acid, 2,4,5-triphenylimidazole 1,2,4,5-tetraphenylimidazole, 2-phenylphenanthro [9,10-d] imidazole, 2- (o-cyanophenyl) phenanthro [9,10-d] imidazole, 2- (m -Cyanophenyl) phenanthro [9,10-d] imidazole, 2- (p-cyanophenyl) phenanthro [9,10-d] imidazole, hydroquinone, 2-t-butylhydroquinone, 2,5-di-t-butyl And hydroquinone and 2,5-bis (2,4-dimethylphenyl) hydroquinone.

  Among the compounds described above, 1,1-bis (4-hydroxyphenyl) cyclohexane, 1,1,2,2-tetrakis (4-hydroxyphenyl) ethane, 1,1,2,2-tetrakis (4 -Hydroxyphenyl) phenolic host compounds such as ethylene, diphenic acid bis (dicyclohexylamide), amide based host compounds such as fumaric acid bisdicyclohexylamide, 2- (m-cyanophenyl) phenanthro [9,10-d] An imidazole host compound such as imidazole is advantageous in terms of inclusion ability, and in particular, a phenol host compound such as 1,1-bis (4-hydroxyphenyl) cyclohexane is advantageous in terms of easy industrial use. It is.

  These host compounds may be used individually by 1 type, and may use 2 or more types together.

  These organic compounds are mainly used in a solid state. The organic compound is preferably a powdered solid from the viewpoint of contact efficiency with hydrogen gas, etc., but is not limited to this, and may be granular or agglomerated, and may be crystalline or amorphous. Any of (amorphous) may be used. When the organic compound is a powdery solid, the particle size is not particularly limited, but in general, it is preferably about 1 mm or less.

  These organic compounds can also be used as an organic compound-containing composite material supported on a porous material. In this case, the porous material supporting the organic compound includes, but is not limited to, intercalation compounds such as clay minerals and montmorillonites in addition to silicas, zeolites and activated carbons. . Such an organic compound-containing composite material is prepared by, for example, dissolving the above-described organic compound in a solvent that can dissolve the organic compound, impregnating the solution in a porous material, drying the solvent, and drying under reduced pressure. Can be manufactured. Although there is no restriction | limiting in particular as the load of the organic compound with respect to a porous material, Usually, it is about 10 to 80 weight% with respect to a porous material.

  A host compound such as 1,1-bis (4-hydroxyphenyl) cyclohexane described above is known to incorporate various guest molecules to form a crystalline inclusion compound. It is also known that an inclusion compound is formed by direct contact reaction with a guest compound (which may be in a solid, liquid, or gas state). For this reason, gas molecules called hydrogen gas can be brought into contact with an organic compound as a host compound to efficiently incorporate the hydrogen molecules into the clathrate compound, thereby stably storing hydrogen. In the present invention, the organic compound storing hydrogen in this way is used as a hydrogen gas supply source, and hydrogen is released from or extracted from the hydrogen storage organic compound and used for catalytic reductive decomposition of the oxidizing component.

Examples of the method of bringing hydrogen gas into contact with the organic compound in order to store the hydrogen gas in the organic compound include the following methods.
(1) Method of contacting hydrogen gas with a solid organic compound under pressurized conditions
(2) A method in which hydrogen gas is brought into contact with an organic compound in a gaseous state and hydrogen is taken into the obtained solid substance.
(3) Method of contacting hydrogen gas with a heated organic compound and then cooling

In the method of (1) above, the pressurization condition for bringing hydrogen gas into contact with the solid organic compound is preferred because the higher the pressure, the greater the hydrogen storage amount and storage speed. Not only will the equipment be expensive, it will also be necessary to satisfy the conditions of the high-pressure gas storage method. Usually, the pressurizing condition is higher than the normal pressure and 1.0 × 10 ^{−10 to} 200 MPa or less, particularly 0.1 to 70 MPa, substantially in particular about 0.1 to 0.9 MPa. It is preferable that the pressure is higher than the pressure. In addition, the longer the contact time, the larger the hydrogen storage amount. However, from the viewpoint of work efficiency and the like, it is preferably about 0.01 to 24 hours.

In the method (2), a method of heating the organic compound as a gaseous state can be mentioned. The heating temperature in that case should just be not high temperature which the said organic compound will decompose | disassemble, and there is no restriction | limiting in particular, Generally room temperature-about 300 degreeC are preferable. Moreover, as a method of cooling the organic compound gasified by heating etc., the method of naturally cooling at normal temperature may be sufficient, and you may cool rapidly or forcibly using a cooling medium. On the other hand, the hydrogen condition is not particularly limited as long as hydrogen is in a gaseous state, and may be in a normal temperature, high temperature, or low temperature state. Moreover, there is no restriction | limiting in particular also about the pressure conditions of hydrogen gas, However, It is preferable that it is 1.0 * 10 < ^-10 > -200MPa, Especially 0.1-70MPa. Moreover, there is no restriction | limiting in particular about the time which makes the gasified organic compound and hydrogen gas contact, However It is preferable to set it as about 0.01 to 24 hours from surfaces, such as working efficiency.

In the method of (3) above, the heating temperature when bringing hydrogen into contact with the organic compound is not particularly limited as long as it is a temperature equal to or lower than the melting point or decomposition temperature of the organic compound. About 300 degreeC is preferable. Moreover, as a method for cooling the organic compound after heating, a method of natural cooling at room temperature may be used, or a cooling medium may be used to rapidly or forcibly cool the organic compound. On the other hand, the hydrogen condition is not particularly limited as long as hydrogen is in a gaseous state, and may be in a normal temperature, high temperature, or low temperature state. Moreover, there is no restriction | limiting in particular also about the pressure conditions of hydrogen gas, However, It is preferable that it is 1.0 * 10 < ^-10 > -200MPa, Especially 0.1-70MPa. Moreover, there is no restriction | limiting in particular about the time which an organic compound and hydrogen gas contact at high temperature, However, It is preferable to set it as about 0.01 to 24 hours from surfaces, such as working efficiency. Furthermore, it is preferable to set it as about 1-7 days about the period left after cooling and leaving.

  In these methods, the hydrogen gas to be brought into contact with the organic compound is preferably a high-purity hydrogen gas. However, as will be described later, when using a host compound having hydrogen selective inclusion ability, It may be a mixed gas with other gases.

  The hydrogen clathrate compound thus obtained differs depending on the type of host compound used, the contact conditions with hydrogen, etc., but usually clathrates 0.1 to 20 moles of hydrogen molecule per mole of host compound. It is a hydrogen clathrate compound.

  Such a hydrogen clathrate compound can stably store hydrogen over a long period of time at normal temperature and normal pressure (0.1 to 1 MPa). Moreover, since this hydrogen clathrate compound is excellent in handleability as compared with high-pressure hydrogen gas and is in a solid state, it can be easily stored and transported in a glass, metal, plastic or the like container.

  As a method for extracting hydrogen from the organic compound storing hydrogen in this way, when the hydrogen is stored in a pressurized state, it can be extracted by reducing the pressurized state and heating. But you can take it out. Furthermore, stored hydrogen can also be taken out by performing heating and pressure reduction simultaneously.

In particular, in order to release hydrogen from the aforementioned hydrogen clathrate compound, depending on the type of the host compound, the pressure is reduced to about 1.0 × 10 ^{−2 to} 1.0 × 10 ⁻⁵ MPa from normal pressure or normal pressure. Then, it may be heated to about 30 to 200 ° C., particularly about 40 to 100 ° C., whereby hydrogen can be easily released from the hydrogen clathrate compound and used for various applications.

  The host compound after releasing hydrogen from the hydrogen clathrate compound has a selective clathrate ability of hydrogen and can be effectively reused. Therefore, after hydrogen is stored in an organic compound, hydrogen is released at normal pressure or pressure using an organic compound having a hydrogen storage history in which the storage and release operation is repeated once or two or more times. By pressing and contacting, hydrogen can be easily and efficiently stored again.

  Hereinafter, the present invention will be described more specifically with reference to examples.

  In the following, 1,1-bis (4-hydroxyphenyl) cyclohexane (hereinafter abbreviated as “BHC”) is used as the organic compound for storing hydrogen, and the commercially available hydrogen is 99.99% or more. Using high-purity hydrogen, this high-purity hydrogen gas was brought into contact with BHC at 10 MPa for 8 hours to obtain a hydrogen clathrate compound in which hydrogen was stored at a ratio of 0.1 wt% with respect to BHC. And this hydrogen clathrate compound was preserve | saved under normal temperature normal pressure, and it was set as the hydrogen gas supply source, this hydrogen clathrate compound was heated at 50 degreeC, hydrogen gas was discharge | released, and it used for reaction.

Example 1: Treatment of nitrate-containing wastewater The nitrate-containing wastewater was treated according to the method shown in FIG. As the catalyst tower, a column packed with 40 g (about 40 mL) of 0.5 wt% Pt-supported Al ₂ O ₃ catalyst was used, and NH ₄ NO ₃ aqueous solution (2000 ppm as N) was heated to 140 ° C. in this column. Then, hydrogen gas generated from the hydrogen clathrate compound was added at a supply pressure of 0.8 MPa and a supply amount of 30 mL-N / min, and then sent at a rate of 3.0 mL / min (SV = 4.5 hr ⁻¹ ). Then, NH ₄ NO ₃ was decomposed.

When the NH ₄ ⁺ and NO ₃ ⁻ concentrations of the obtained treated water were measured, N was 15 ppm and 3 ppm, respectively, and a NH ₄ NO ₃ removal rate of 99% or more was achieved.

Example 2: Deoxygenation treatment A three-necked flask with a capacity of 1 L was filled with soft water (dissolved oxygen concentration of about 7 mg / L) and maintained at 55 ° C. In addition, the gas phase part always flowed nitrogen gas to prevent outside air from entering. To this, 10 g of a catalyst having 1% by weight of Pt supported on γ-Al ₂ O ₃ was added and stirred for 1 hour. After the oxygen concentration in the water became constant, hydrogen gas was added at a rate of 50 mL / min and the decrease in dissolved oxygen concentration over time was measured. As a result, the dissolved oxygen concentration was 1 mg / L after 2 hours, and 4 After a time, it decreased to 0.1 mg / L.

  The method for treating water containing oxidizing components according to the present invention is effective for treating wastewater containing various oxidizing components such as dissolved oxygen and nitrates, and by using a hydrogen storage organic compound as a hydrogen supply source, good work can be achieved. Therefore, catalytic reductive decomposition of water containing oxidizing components can be performed.

The method for treating water containing an oxidizing component of the present invention includes, for example, a combination of nitric acid waste water and ammonia waste water discharged from a semiconductor manufacturing plant to produce ammonium nitrate, whereby an oxidizing component (HNO ₃ ) and a reducing component ( It is extremely effective for treating nitrate-containing wastewater prepared as wastewater in the form of a compound containing NH ₃ ). The present invention is also effective for the treatment of water containing dissolved oxygen such as boiler feed water, hot water supply, and warm water for heating.

It is a systematic diagram which shows embodiment of the processing method of the oxidizing component containing water of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Storage tank 2 Pump 3 Heat exchanger 4 Pressure control valve 5 Heater 6 Hydrogen generator 7 Compressor 8 Catalyst tower 8A Catalyst layer

Claims (7)

  In a method for treating oxidizing component-containing water, in which hydrogen gas is added to oxidizing component-containing water and reacted in the presence of a catalyst to decompose and remove the oxidizing component, an organic material storing hydrogen gas as a hydrogen gas supply source A method for treating oxidizing component-containing water, comprising using a compound and adding hydrogen gas released from the hydrogen storage organic compound to the oxidizing component-containing water.   The treatment of oxidizing component-containing water according to claim 1, wherein the oxidizing component is dissolved oxygen, hydrogen gas is added to the oxidizing component-containing water, and then contacted with a catalyst supporting a metal component. Method.   2. The method for treating oxidizing component-containing water according to claim 1, wherein the oxidizing component is nitrate, and hydrogen gas is added to the oxidizing component-containing water, followed by heating in the presence of a catalyst.   The method for treating water containing an oxidizing component according to any one of claims 1 to 3, wherein the organic compound is supported on a porous material.   5. The method for treating oxidizing component-containing water according to any one of claims 1 to 4, wherein the organic compound is a compound that forms a hydrogen molecule compound upon contact with hydrogen gas.   6. The method for treating oxidizing component-containing water according to claim 5, wherein the hydrogen molecule compound is a hydrogen clathrate compound having the organic compound as a host compound.   7. The oxidizing component-containing water according to claim 6, wherein the organic compound is one or more selected from the group consisting of a monomolecular host compound, a polymolecular host compound, and a polymer host compound. Processing method.

Images