TWI491443B - Drainage treatment catalyst and drainage method using the catalyst - Google Patents

Description

Catalyst for drainage treatment and drainage treatment method using the same

The present invention relates to a catalyst for drainage treatment and a wet oxidation treatment method using the drainage of the catalyst. The catalyst of the present invention is particularly suitable for wet oxidation treatment of wastewater under high temperature and high pressure conditions.

Conventional wastewater treatment methods are known as biological treatment, combustion treatment, and Zimmermann method.

In biological treatment, aerobic treatment such as activated sludge method and biofilm method has been used; anaerobic treatment such as methane fermentation method; and a combination of aerobic treatment and anaerobic treatment. In particular, the aerobic treatment using microorganisms is widely used as a drainage treatment method. However, the aerobic microbial treatment has the following problems: it will be suitable for complex effects of bacteria, algae, protozoa, etc., and contains a high concentration. When the drainage of organic matter and nitrogen compounds is supplied to aerobic microorganisms, it is necessary to prepare the environment suitable for the growth of microorganisms, dilute the drainage and adjust Ph, etc., so that the device and operation are complicated, and the remaining sewage must be disposed of due to the generation of excess sludge. Mud, which increases the overall processing cost.

In terms of combustion treatment, there is a problem that a large amount of drainage and treatment costs are significantly increased due to the cost of fuel costs and the like. There are also concerns about secondary pollution caused by combustion and exhaust.

In the Zimmermann method, the wastewater is treated in the presence of an oxygen-containing gas under high temperature and high pressure, but generally the treatment efficiency is low and there is a need for secondary treatment equipment.

In particular, in recent years, since the types of the contaminated substances contained in the treated wastewater are increased and high-quality treated water is required, the above-described conventional techniques cannot sufficiently cope with them.

Among them, various drainage treatment methods have been proposed for the purpose of high drainage treatment efficiency and high-grade treatment water. For example, a wet oxidation method using a solid catalyst (hereinafter referred to as "catalyst wet oxidation treatment") can be used to obtain a high-grade treatment water quality and is excellent in economy. In order to improve the processing efficiency and processing capability of such a catalyst wet oxidation treatment, various catalysts are proposed. For example, in JP-A-49-44556, a noble metal such as palladium or platinum is supported on alumina or ruthenium oxide. A catalyst for a carrier of alumina, cerium oxide gel, activated carbon or the like. A catalyst composed of copper oxide and nickel oxide is proposed in Japanese Laid-Open Patent Publication No. SHO-49-94157.

However, the components contained in the general drainage are not single, and in addition to organic substances, nitrogen compounds, sulfur compounds, organic halogen compounds, and the like are often contained. In the treatment of drainage containing various kinds of dirty substances, the above-mentioned catalyst cannot be used sufficiently. Process the ingredients.

In order to solve such a catalyst, the present inventors have proposed a catalyst having high durability and excellent catalytic activity in US-A-4751005 and Japanese Patent Laid-Open No. Hei 5-138027.

However, in terms of the durability of the catalyst and the efficiency of the processing, a further improvement is expected.

The object of the present invention is to provide a method for wet oxidation treatment of drainage water In the meantime, it is possible to maintain excellent catalyst activity and durability for a long period of time, and to improve the processing efficiency, and a wet oxidation treatment method using the drainage of the catalyst.

The inventors of the present invention have a catalyst having superior catalytic activity and durability as compared with the above-mentioned catalyst (specifically, the catalysts described in US-A-4751005 and Japanese Patent Laid-Open No. 5-138027). As a result of repeated research, it was found that a catalyst contains a specific component of a catalyst carrier and an active ingredient, and the number of active ingredient particles per unit area of the carrier is a specific value or more, and further, the active ingredient Most of the present invention is present at a certain depth in the surface of the carrier to complete the present invention.

The catalyst of the present invention which solves the above problems is characterized in that a noble metal is used as an active component, and a carrier supporting the active component contains at least one selected from the group consisting of iron, titanium, lanthanum, aluminum, and zirconium. The compound of the element, wherein at least 70% by mass of the active ingredient supported on the carrier is present at a position within 500 μm from the surface of the carrier, and the active ingredient has an average particle diameter of 0.5 to 20 nm.

Furthermore, the present invention is a wet oxidation treatment method using drainage of the above-mentioned catalyst in a wet oxidation treatment method in which the drainage is carried out in the presence of a solid catalyst.

The catalyst of the present invention can stabilize the drainage process with high processing performance for a long period of time. By subjecting the drainage to wet oxidation treatment using the catalyst, a high level of purified treated water can be obtained.

The catalyst system of the present invention can be applied to a wet oxidation treatment catalyst for drainage, characterized in that a noble metal is used as an active component, and the active agent is loaded. The carrier is a compound comprising at least one element selected from the group consisting of iron, titanium, lanthanum, aluminum, and zirconium, and at least 70% by mass of the active ingredient supported by the carrier is present within 500 μm from the surface of the carrier. Above, and the active ingredient has an average particle diameter of 0.5 to 20 nm.

The active ingredient in the present invention means having an increased oxidation of an organic compound or a nitrogen compound contained in the wastewater. A component that decomposes the reaction rate (hereinafter also referred to as the "active action"). In the present invention, a noble metal is used as an active ingredient.

Usually, the surface of the carrier has the presence of fine irregularities, and the unevenness is almost insignificant in 500 μm in the range of 70% by mass relative to the active ingredient specified in the present invention. However, the surface of the carrier is determined by observing a section or the like. For example, in a generally used particulate catalyst, the cross section is circular, as long as it is measured in the depth direction within a range of 500 μm on the circumference of the circle. Even in the examples described below, the profile of the particulate catalyst measured by EPMA analysis was circular. The catalyst of the present invention, when the active ingredient is only supported on the surface of the carrier, that is, the case where 70% by mass of the active ingredient is present in the range of 0 nm or extremely close to 0 nm.

According to the study by the inventors of the present invention, most of the active ingredients supported by the general preparation method permeate into the interior of the carrier, and most of the active ingredients are mostly utilized only effectively. Here, the inventors of the present invention have achieved the above-described catalyst by focusing on the distribution state of the unique active ingredient.

The above active ingredient is expected to contain at least one noble metal selected from the group consisting of silver, gold, platinum, palladium, rhodium, ruthenium and osmium. The at least one precious metal may be used in a metal state or in the form of a compound. by Catalysts containing such active ingredients are expected to exhibit particularly excellent activity in wet oxidation of wastewater. In view of the above, it is preferred that the active ingredient contains a noble metal selected from the group consisting of platinum, rhodium, palladium, platinum and rhodium, and a combination of platinum and gold or a compound containing the noble metal.

When the active ingredient is used in the form of a compound containing a noble metal, the active ingredient is not particularly limited as long as it contains a noble metal selected from the above active ingredients, and a water-soluble compound is preferred, and an inorganic compound is more preferable. It may also be an emulsion type, a slurry or a gelatinous compound, and an appropriate compound may be used depending on the preparation method of the catalyst and the kind of the carrier.

For example, when platinum is used as the active ingredient, for example, platinum black, platinum oxide, platinum chloride, platinum chloride, chloroplatinic acid, sodium chloroplatinate, potassium chloronitrite, dinitrodiammine platinum, or the like can be used. Ammonia platinum, hexahydroxyplatinic acid, cis-dichlorodiamine platinum, tetraammine platinum dichloride, tetraammine platinum hydroxide, hexaammine platinum hydroxide, potassium tetrachloroplatinate, and the like.

For example, when palladium is used as the active component, for example, palladium chloride, palladium nitrate, dinitrodiammine palladium, dichlorodiammine palladium, tetraammine palladium dichloride, cis-dichlorodiammine palladium can be used. , palladium black, palladium oxide, tetraammine palladium hydroxide, and the like.

For example, when hydrazine is used as the active ingredient, for example, cerium chloride, cerium nitrate, hexacarbonyl-μ-chlorodichloroindene, cerium oxide, tridecacarbonyl trifluorene, cerium acetate, potassium citrate or hexachloroantimonic acid can be used. Potassium, hexaammine antimony trichloride, tetra-terminated potassium oxyphthalate, and the like.

For example, when gold is used as the active ingredient, for example, chloroauric acid, gold potassium cyanide, potassium hydride gold cyanide or the like can be used. When hydrazine is used as an active ingredient, for example, ruthenium chloride or the like can be used. When silver is used as the active ingredient, for example, silver cyanide or cyanide can be used. Silver and potassium. When hydrazine is used as the active ingredient, for example, cerium chloride, cerium sulfate, cerium nitrate, cerium acetate or the like can be used.

The compound to be used is not particularly limited, and those skilled in the art can be suitably selected from the above-mentioned compounds. For example, the catalyst of the present invention can be produced by the method described in the examples.

In the present invention, the carrier supporting the above active ingredient is expected to be a compound containing at least one element selected from the group consisting of iron, titanium, ruthenium, aluminum and zirconium. Examples of the carrier include at least one oxide selected from the group consisting of iron, titanium, ruthenium, aluminum, and zirconium, or one or more composite oxides. In particular, it is recommended that the carrier contain at least titanium or zirconium. From the viewpoint of mechanical strength and durability of the catalyst, preferred carriers include titanium oxide (titanium oxide) or mixed oxide of titanium-containing oxide. Or a composite oxide (for example, TiO ₂ -ZrO ₂ , TiO ₂ -Fe ₂ O ₃ , TiO ₂ -SiO ₂ , TiO ₂ -Al ₂ O _{3 ,} etc.). Among them, particularly preferred are a combination of a titanium oxide and a composite oxide of titanium and zirconium; a combination of an oxide of titanium and an oxide of iron with a composite oxide of titanium and iron; and an oxide of titanium.

The combination of the above active ingredient and a carrier is exemplified by, for example, Pt-TiO ₂ , Pd-TiO ₂ , Ru-TiO ₂ , Pt-Pd-TiO ₂ , Pt-Rh-TiO ₂ , Pt-Ir-TiO ₂ , Pt-Au. -TiO ₂ , Pt-Ru-TiO ₂ , Pd-Rh-TiO ₂ , Pd-Ir-TiO ₂ , Pd-Au-TiO ₂ , Pd-Ru-TiO ₂ , Pt-TiO ₂ -ZrO ₂ , Pd-TiO ₂ -ZrO ₂ , Ru-TiO ₂ -ZrO ₂ , Pt-Pd-TiO ₂ -ZrO ₂ , Pt-Rh-TiO ₂ -ZrO ₂ , Pt-Ir-TiO ₂ -ZrO ₂ , Pt-Au-TiO ₂ - ZrO ₂ , Pt-Ru-TiO ₂ -ZrO ₂ , Pd-Rh-TiO ₂ -ZrO ₂ , Pd-Ir-TiO ₂ -ZrO ₂ , Pd-Au-TiO ₂ -ZrO ₂ , Pd-Ru-TiO ₂ - ZrO ₂ , Pt-Fe ₂ O ₃ -TiO ₂ , Pd-Fe ₂ O ₃ -TiO ₂ , Ru-Fe ₂ O ₃ -TiO ₂ , Pt-Pd-Fe ₂ O ₃ -TiO ₂ , Pt-Ir-Fe ₂ O ₃ -TiO ₂ , Pt-Au-Fe ₂ O ₃ -TiO ₂ , Pt-Ru-Fe ₂ O ₃ -TiO ₂ , Pd-Rh-Fe ₂ O ₃ -TiO ₂ , Pd-Ir-Fe ₂ O ₃ -TiO ₂ , Pd-Au-Fe ₂ O ₃ -TiO ₂ , Pd-Ru-Fe ₂ O ₃ -TiO ₂ , Pt-TiO ₂ -SiO ₂ , Pd-TiO ₂ -SiO ₂ , Ru-TiO ₂ - SiO ₂ , Pt-Pd-TiO ₂ -SiO ₂ , Pt-Rh-TiO ₂ -SiO ₂ , Pt-Ir-TiO ₂ -SiO ₂ , Pt-Au-TiO ₂ -SiO ₂ , Pt-Ru-TiO ₂ - SiO ₂ , Pd-Rh-TiO ₂ -SiO ₂ , Pd-Ir-TiO ₂ -SiO ₂ , Pd-Au-TiO ₂ -SiO ₂ , Pd-Ru-TiO ₂ -SiO ₂ , Pt -TiO ₂ -Al ₂ O ₃ , Pd-TiO ₂ -Al ₂ O ₃ , Ru-TiO ₂ -Al ₂ O ₃ , Pt-Pd-TiO ₂ -Al ₂ O ₃ , Pt-Rh-TiO ₂ -Al ₂ O ₃ , Pt-Ir-TiO ₂ -Al ₂ O ₃ , Pt-Au-TiO ₂ -Al ₂ O ₃ , Pt-Ru-TiO ₂ -Al ₂ O ₃ , Pd-Rh-TiO ₂ -Al ₂ O ₃ Pd-Ir-TiO ₂ -Al ₂ O ₃ , Pd-Au-TiO ₂ -Al ₂ O ₃ , Pd-Ru-TiO ₂ -Al ₂ O ₃ or the like. Here, the symbol of Pt-TiO ₂ or the like means a composition containing Pt and TiO _{2 in} the catalyst. The above-mentioned combination examples are generally oxides of a noble metal, and the noble metal is merely an exemplified metal, and the purpose is not to limit the combination of the active ingredients of the present invention to the above-exemplified examples.

The content ratio of the above-mentioned active ingredient constituting the catalyst of the present invention to the carrier supporting the active ingredient is not particularly limited. However, when the active ingredient is a noble metal, from the viewpoints of catalyst activity and catalyst durability, The active ingredient is expected to be 0.07% by mass or more, more preferably 0.1% by mass or more, based on the carrier. It is expected to be 0.7% by mass or less, and more preferably 0.6% by mass or more. Further, the content ratio of the active ingredient is calculated by using a noble metal as a metal.

The active ingredient of the present invention is not limited to the above-exemplified ones, and may contain any combination of other elements or other elements, and may contain, for example, an alkali metal, an alkaline earth metal, or another transition metal. The alkali metal is preferably Na, K, and Cs, and the alkaline earth metal is preferably Mg, Ca, Sr, and Ba. Other transition metals are preferably La, Ce, Pr and Y. It is preferred that the addition of these elements can impart a high dispersion load to the precious metal.

In order to exhibit the effect of the above-mentioned active component, 70% by mass or more of the active component contained in the catalyst is present at a surface portion of a depth of 500 μm or less from the surface of the carrier. That is, the active ingredient of the catalyst of the present invention is preferably supported on an eggshell type (Egg-Shell type). The eggshell type refers to a catalyst which, when observing the cross section of the carrier, is covered by a shell as indicated by the text, and the active ingredient is concentratedly supported at a certain depth from the surface of the carrier. Due to active ingredients Focusing on the surface, the micropore structure of the carrier surface can be effectively utilized in the catalyst reaction. Thereby, the reaction in the surface of the catalyst can be greatly promoted to effectively treat the dirty matter in the drainage. Further, the active component supported in the micropores is not lost by the friction between the carriers, so that the durability of the entire catalyst can be greatly improved.

The ratio of the active ingredient (% by mass) present in the surface layer of the catalyst from the surface of the carrier to the depth of 500 μm relative to the total amount of the active component supported by the catalyst, and the contact in the catalyst profile by EPMA (electron probe microanalysis) The amount of the active ingredient in the surface layer portion was subjected to line analysis, and the distribution ratio of the catalyst surface to the depth of 500 μm in the area ratio was calculated and determined. As described above, it is proposed that 70% by mass or more of the total amount of active ingredients detected by EPMA is present on the surface of the carrier to a depth of 500 μm, preferably within 300 μm, more preferably within 200 μm, and preferably within 100 μm; More than % is preferable, more preferably 90% by mass or more, and most preferably 95% by mass or more.

In order to promote the wet oxidation reaction in which the dirty matter in the drainage and the oxygen in the air are effectively contacted on the catalyst, it is proposed that the active component on the catalyst is highly dispersed in the state of the fine particles. Therefore, it is proposed that the average particle diameter of the active component supported by the catalyst is 0.5 nm or more, preferably 0.7 nm or more, more preferably 1 nm or more. Further, it is proposed that the average particle diameter of the active component supported by the catalyst is 20 nm or less, preferably 18 nm or less, more preferably 17 nm or less. When the particle diameter of the active ingredient is less than 0.5 nm, the treatment performance in the initial stage is improved. However, since the particles of the active ingredient are too small, aggregation tends to occur, and sufficient durability may not be obtained. Further, when the particle diameter of the active ingredient is more than 20 nm, there is a case where sufficient durability cannot be obtained due to the occurrence of load marks.

The average particle diameter of the active component supported by the catalyst was determined by TPD analysis (Temperature Programmed Desorption) and the amount of chemical adsorption was measured by the CO pulse method. For each particle diameter of the active component, the surface layer portion of the catalyst can be removed and observed using a transmission electron microscope at a magnification of 1 to 1,000,000 times.

As described above, by allowing the active ingredient to be present in the surface layer portion of the catalyst and controlling the particle diameter of the active ingredient, that is, it is easy to chemically adsorb the contaminated substance in the drainage, and the active ingredient particles and the dirty substance become in effective contact, thereby greatly promoting Decomposition reaction of dirty substances.

The specific surface area of the carrier is preferably 20 m ² /g or more. When the specific surface area of the catalyst is less than 20 m ² /g, the activity of the catalyst is insufficient. More preferably, it is 25 m ² /g or more, and more preferably 30 m ² /g or more. When the specific surface area exceeds 70 m ² /g, the catalyst is liable to be broken and the catalytic activity is also lowered. Therefore, a preferred specific surface area is 70 m ² /g or less, more preferably 60 m ² /g or less, and most preferably 55 m ² /g or less.

In the method for measuring the specific surface area of the catalyst in the present invention, a BET method for analyzing the adsorption of nitrogen is employed.

The crystal structure of the carrier is not particularly limited, and may have an anatase crystal structure or a crystal structure other than an anatase crystal structure, but a carrier having an anatase crystal structure is preferred.

The catalyst (carrier) shape of the present invention is, for example, a pellet, a pellet, a sphere, a ring, a honeycomb, or the like, and the shape can be appropriately selected depending on the purpose, and is not particularly limited.

The pore volume of the carrier is not particularly limited and is expected to be 0.20 ml/g. The above is preferably 0.25 ml/g or more, more preferably 0.50 ml/g or less, and even more preferably 0.45 ml/g or less. When the micropore volume is less than 0.20 ml/g, the carrier may not sufficiently support the active ingredient, and the activity may be lowered. When the pore volume exceeds 0.50 ml/g, the durability of the catalyst is lowered. For example, when used in the wet oxidation treatment, the catalyst is damaged early.

The size of the catalyst is not particularly limited. For example, when the catalyst is in the form of particles (hereinafter referred to as "granular catalyst"), the average particle diameter is preferably 1 mm or more, more preferably 2 mm or more. When a granular catalyst having an average particle diameter of less than 1 mm is filled in the reaction column, the pressure loss increases, and the catalyst layer may be clogged by suspended matter contained in the drainage. The average particle diameter of the particulate catalyst is preferably 10 mm or less, more preferably 7 mm or less. Since the granular catalyst having an average particle diameter of more than 10 mm cannot obtain a sufficiently geometric surface area, the contact efficiency with the water to be treated is lowered, and sufficient processing ability cannot be obtained.

When the catalyst is formed into pellets (hereinafter referred to as "pill-like catalyst"), the average particle diameter is preferably 1 mm or more, more preferably 2 mm or more, and most preferably 10 mm or less, and 6 mm or less. Better. Further, the longer length of the pellet-shaped catalyst is preferably 2 mm or more, more preferably 3 mm or more, more preferably 15 mm or less, and still more preferably 10 mm or less. If a pelletized catalyst having an average particle diameter of less than 1 mm or a length of less than 2 mm is filled in the reaction tower, there is a case where the pressure loss is increased, and the average particle diameter exceeds 10 mm or the longer length exceeds 15 mm. The pellet-like catalyst does not have a sufficiently geometric surface area, so that the contact efficiency with the water to be treated is lowered, and there is a case where sufficient processing ability cannot be obtained.

Further, when the catalyst is formed into a honeycomb shape (hereinafter also referred to as "honeycomb catalyst"), the diameter of the through hole is preferably 1.5 mm or more, more preferably 2.5 mm or more, and 10 mm or less. For better, it is better to be 6mm or less. Further, the thickness between adjacent through holes is preferably 0.1 mm or more, more preferably 0.5 mm or more, and most preferably 3 mm or less, and more preferably 2.5 mm or less. Further, the opening ratio of the catalyst surface is preferably 50% or more, more preferably 55% or more, more preferably 90% or less, and even more preferably 85% or less, relative to the total surface area. If a honeycomb catalyst having a diameter of less than 1.5 mm is filled in the reaction tower, there is a case where a pressure loss is increased, and when a honeycomb catalyst having a diameter exceeding 10 mm is filled in the reaction tower, the pressure loss is small. However, the contact with the treated water is reduced, and the catalytic activity is reduced. Although the honeycomb catalyst having a thickness of less than 0.1 mm between the through holes has the advantage of quantifying the catalyst, the mechanical strength of the catalyst is lowered. Although the honeycomb catalyst having a thickness exceeding 3 mm has sufficient mechanical strength, the amount of use of the catalyst raw material increases, and the cost increases. The opening ratio of the catalyst surface is desirably within the above range from the viewpoint of the mechanical strength of the catalyst and the catalytic activity.

In the case of a honeycomb catalyst, it is produced by a method of extrusion molding or a method of entraining a sheet-like element, similarly to a so-called monolithic carrier. The shape of the gas port (cell shape) may be any of a hexagonal shape, a quadrangular shape, a triangular shape, or a waveform. The cell density (number of cells/unit sectional area) can be appropriately selected as long as it has a general knowledge in the technical field.

In addition, when the drainage containing the suspended matter is subjected to the wet oxidation treatment in which the catalyst is filled in the reaction tower, the solid matter and the suspension in the drainage There is a case where the catalyst layer is blocked by precipitation of the floating material, etc., and therefore, a honeycomb catalyst is particularly recommended for use in the above-mentioned catalyst.

The method of modulating the catalyst in the present invention is not particularly limited, and can be easily prepared by a conventional method. Examples of the method of supporting the catalyst active component in the carrier include a kneading method, a dipping method, an adsorption method, a spray method, and an ion exchange method.

Although not limited to the above, the following methods are used in the following examples. For example, sodium carbonate is added to the aqueous solution of the desired active ingredient, and the carrier is shaken frequently and sprayed with the liquid. Thereafter, the carrier was dried while being rotated in a hot air stream, and fired with a hydrogen-containing gas to obtain a catalyst. The conditions of the aqueous solution concentration of the active ingredient, the conditions for spraying the liquid, the drying temperature, the firing temperature, the firing time, and the like can be easily selected as long as they have a general knowledge in the technical field.

By configuring the catalyst as described above, it is possible to maintain long-term excellent catalyst activity and durability of the catalyst. Further, as described above, by using the catalyst of the present invention and treating the drainage water by wet oxidation treatment, a high-grade purified treated water can be obtained.

Hereinafter, the wet oxidation treatment method of the drainage using the catalyst of the present invention will be described in detail.

The type of drainage treated by the wet oxidation treatment of the present invention can effectively treat the drainage containing any one or more selected from the group consisting of organic compounds, nitrogen compounds, and sulfur compounds without particular limitation. Such drainage system is: drainage discharged from various industrial factories such as chemical factories, electronic parts manufacturing equipment, food processing equipment, metal processing equipment, metal plating equipment, printing plate making equipment, and photographic equipment; or by thermal power generation or atomic energy. Power generation equipment such as power generation The drainage that is discharged by the preparation, for example, is: EOG (ethylene oxide gas) manufacturing equipment; drainage of methanol, ethanol, higher alcohol, etc., especially from acrylic acid, acrylate, methacrylic acid, An aliphatic carboxylic acid such as methacrylate or an ester thereof; or an organic carboxylic acid or an aromatic carboxylic acid ester such as phthalic acid or phthalic acid ester, or the like, which is discharged from an organic matter. Further, it may be a drain containing a nitrogen compound such as an amine or an imine, ammonia or hydrazine. Can also be made from paper. Pulp, fiber, steel, ethylene. BTX, coal gasification, meat, medicines, etc., which discharges sulfur compounds from factories in various industrial sectors. Examples of the sulfur compound herein include inorganic sulfides such as hydrogen sulfide, sodium sulfide, potassium sulfide, sodium hydrosulfide, thiosulfate, and sulfite, and mercaptans; and organic sulfur compounds such as sulfonic acids. It can also be used for drainage of sewer water or urine. Alternatively, it may be a drainage containing harmful substances such as dioxins and halogenated alkanes, diethylhexyl phthalate, anthraquinone, or the like, or an environmental hormone compound.

In addition, the "drainage" in the present invention is not limited to the so-called industrial drainage discharged from the above-mentioned industrial factory, and it is generally included as long as it contains any one of an organic compound, a nitrogen compound, and a sulfur compound. There is no particular limitation on the source of the liquid.

The catalyst of the present invention can be used in a wet oxidation treatment, but it is particularly recommended to use it when the drainage is heated and the drainage is subjected to catalytic wet oxidation treatment under the pressure of maintaining the liquid phase.

Hereinafter, a method of performing drainage treatment using the processing apparatus of Fig. 1 will be described. Fig. 1 is a schematic view showing an embodiment of a processing apparatus in a wet oxidation treatment using one of the oxidation treatment steps, but in the present invention The device to be used is not limited to this.

The drain supplied from the drain supply source is supplied to the pump 5 through the drain supply line 6 and sent to the heater 3. The space velocity at this time is not particularly limited and may be appropriately determined depending on the processing ability of the catalyst.

When the catalyst of the present invention is used, the wet oxidation treatment can be carried out in the presence or absence of an oxygen-containing gas. However, if the oxygen concentration in the drainage is increased, the oxidation of the oxide contained in the drainage can be improved. Since the decomposition efficiency is high, it is desirable to mix an oxygen-containing gas in the drainage.

When the wet oxidation treatment is carried out in the presence of an oxygen-containing gas, for example, the oxygen-containing gas is introduced into the oxygen-containing gas supply line 8, and after the pressure is increased by the compressor 7, it is preferable to mix the water before the drain is supplied to the heater.

The oxygen-containing system of the present invention contains molecular oxygen and/or ozone-containing gas, and if it is such a gas, it can be pure oxygen, polyox gas, air, hydrogen peroxide water, and other oxygen-containing gases produced by the factory. The type of the oxygen-containing gas is not particularly limited, and it is recommended from an economic point of view that air is also used in such gases.

The supply amount of the oxygen-containing gas to the drain is not particularly limited as long as the supply increases the oxidation of the oxide in the drain. The effective amount of decomposition processing capability is sufficient. The supply amount of the oxygen-containing gas is, for example, an oxygen-containing gas flow rate adjustment valve 9 is attached to the oxygen-containing gas supply line 8, so that the supply amount to the drain can be appropriately adjusted. The recommended oxygen-containing gas supply amount is preferably 0.5 times or more of the theoretical oxygen requirement of the oxide in the drainage, more preferably 0.7 times or more, more preferably 5.0 times or less, and more preferably 3.0 times or less. When the supply of oxygen-containing gas is less than 0.5 times, the oxide is not sufficiently oxidized. Wet oxygen There are many residues in the treatment liquid obtained by the treatment. When it exceeds 5.0 times, it is oxidized even if it is supplied with oxygen. The case where the decomposition processing capability is saturated.

In addition, the "theoretical oxygen requirement amount" of the present invention means the amount of oxygen required for oxidation and/or decomposition of an organic compound or a nitrogen compound in the drainage into nitrogen, carbon dioxide, water, and ash. The theoretical oxygen requirement is presented in terms of chemical oxygen demand (COD (Cr)).

The drain water sent to the heater 3 is supplied to the reaction tower 1 equipped with the electric heater 2 after being preheated. When the temperature of the drainage is too high, the drainage in the reaction tower is in a gaseous state, and the organic matter or the like adheres to the surface of the catalyst to deteriorate the catalytic activity. It is therefore recommended to increase the pressure in the reaction column so that the drainage can maintain the liquid phase even at high temperatures. Further, although the drainage temperature in the reaction tower exceeds 370 ° C due to other conditions, high pressure has to be applied in order to maintain the liquid phase state of the drainage, so that the equipment is enlarged and increased. In the case of operating costs, it is recommended that the drainage temperature in the reaction tower should be 270 ° C or less, preferably 230 ° C or less, and more preferably 170 ° C or less. Conversely, when the drainage temperature does not reach 80 ° C, the oxidation of the oxide in the drainage. The decomposition treatment may be difficult to carry out efficiently. Therefore, it is desirable that the drainage temperature in the reaction column is preferably 80 ° C or higher, preferably 100 ° C or higher, and more preferably 110 ° C or higher.

Further, the heating timing of the drainage is not particularly limited, and as described above, the preheated drainage water may be supplied to the reaction tower, or the drainage water supplied to the reaction tower may be heated. The heating method for the drainage is also not particularly limited, and a heater or a heat exchanger may be used, and a heater may be provided in the reaction tower to heat the drainage. A heat source such as steam can be supplied to the drain.

A pressure regulating valve is installed on the drain outlet side of the wet oxidation treatment apparatus, and it is desirable to appropriately adjust the pressure according to the treatment temperature so that the drainage in the reaction tower can maintain the liquid phase. For example, when the treatment temperature is 80 ° C or higher and less than 95 ° C, the drainage at atmospheric pressure is also in a liquid phase state, and although it can be at atmospheric pressure from the viewpoint of economy, it is preferable to pressurize for improving the treatment efficiency. Moreover, when the treatment temperature is 95 ° C, the drainage under atmospheric pressure is mostly vaporized. Therefore, it is desirable to control the pressure so that the drainage can maintain the liquid phase. For example, when the treatment temperature is 95 ° C or more and less than 170 ° C, 0.2 to 1 MPa (Gauge) is added. When the treatment temperature is 170 ° C or higher and 230 ° C or less, a pressure of about 1 to 5 MPa (Gauge) is added, and when the treatment temperature is 230 ° C or more, a pressure of more than 5 MPa (Gauge) is added.

In the wet oxidation treatment used in the present invention, the number, type, shape, and the like of the reaction column are not particularly limited, and a singular or plural combination reaction column used in general wet oxidation treatment can be used, for example, it can be used. Single-tube or multi-tube reaction towers, etc. When a plurality of reaction towers are provided, the reaction towers may be arbitrarily arranged in series or in parallel depending on the purpose.

For the drainage supply method of the reaction tower, various types such as gas-liquid upward cocurrent, gas-liquid downward cocurrent, and gas-liquid two-phase cocurrent flow can be used, and when a plurality of reaction towers are provided, two or more of them can be combined. The method of supply.

When the above-mentioned solid catalyst is used in the wet oxidation treatment in the reaction column, in addition to any one or more of the organic compound, the nitrogen compound and the sulfur compound contained in the drainage, the oxide is oxidized. In addition to improving the efficiency of the decomposition treatment, it can maintain long-term excellent catalyst activity and catalyst durability, and can obtain treated water with high level of purification.

The filling amount of the catalyst charged in the reaction tower is not particularly limited, and can be appropriately determined depending on the purpose. Typically, it is recommended to adjust the filling amount of the catalyst layer, so that the space velocity of the catalyst layer becomes about 0.1hr ^-1 to 10 hr ^-1, to 0.2hr ^-1 to 5hr ^-1 preferably to 0.3hr ^-1 to 3 hr ^{-1 is} better. Hourly space velocity less than 0.1hr ^-1, Catalyst for lowering the amount of processing required huge equipment case, on the contrary, ^-1 exceeds 10 hr, the oxidation reaction will drain the column. Insufficient decomposition processing.

When a plurality of reaction columns are used, different catalysts may be used, and a reaction column packed with a catalyst may be used in combination with a reaction column without a catalyst. Therefore, the method of using the catalyst of the present invention is not particularly limited. .

The shape of the catalyst to be filled is not particularly limited, and it is desirable to use a honeycomb catalyst or a pellet catalyst.

In the reaction tower, it is possible to mix various fillers and internal crops for the purpose of agitation of gas and liquid, improvement of contact efficiency, and reduction of gas-liquid flow.

The oxide in the drainage is oxidized in the reaction tower. Decomposition treatment, however, in the present invention, "oxidation. decomposition treatment" means, for example, treatment of oxidative decomposition of acetic acid into carbon dioxide and water; decarbonation of acetic acid into carbon dioxide and methane; treatment of sulfides and hydrosulfides Oxidation of sulfite or thiosulfate to sulfate; treatment of dimethyl hydrazine by oxidation and oxidative decomposition into ash of carbon dioxide, water, sulfate, etc.; hydrolysis of urea into ammonia and carbon dioxide Oxidative decomposition of ammonia or hydrazine into nitrogen and water; oxidation of dimethyl hydrazine to dimethylhydrazine or methanesulfonic acid, that is, decomposition of easily decomposable oxide into nitrogen, carbon dioxide , water, ash, etc. The treatment of decomposing organic compounds or nitrogen compounds which are difficult to decompose into low molecular weight, or oxidation treatment such as oxidation, including various oxidation and/or decomposition.

In the treatment liquid obtained by the wet oxidation treatment, the organic compound which is hardly decomposable in the oxide is mostly left by the low molecular weight, and the low molecular weight organic compound is a low molecular weight organic acid, especially acetic acid. More residue.

This treatment example is specifically shown in Figure 1, which is oxidized in the reaction tower. After the decomposition treatment, it is taken out as the treatment liquid from the treatment liquid line 10, and if it is appropriately cooled in the cooler 4 as needed, it is separated into a gas and a liquid by the gas-liquid separator 11. At this time, it is desirable to detect the liquid level state using the liquid level controller LC, and perform regulation by the liquid level control valve 13 so that the liquid level of the gas-liquid separator becomes fixed. And the pressure controller PC is used to detect the pressure state, and is regulated by the pressure control valve 12 so that the pressure in the gas-liquid separator becomes fixed.

Or oxidize the drainage. After the decomposition treatment, the treatment liquid is not cooled, but is cooled to some extent in a cooler, and then discharged through a pressure control valve, and then separated into a gas and a liquid by a gas-liquid separator.

Here, although the temperature in the gas-liquid separator is not particularly limited, the wastewater in the reaction tower is subjected to oxidative decomposition treatment, and the treatment liquid contains carbon dioxide. Therefore, it is desirable to increase the temperature in the gas-liquid separator to release the drainage. The carbon dioxide, or the liquid separated by the gas-liquid separator, is subjected to a foaming treatment with a gas such as air to release carbon dioxide in the liquid.

In the temperature control of the treatment liquid, the treatment liquid is supplied to the gas-liquid separator 11 The cooling may be performed by a cooling means such as a heat exchanger (not shown) or a cooler 4, or a cooling means such as a heat exchanger (not shown) or a cooler (not shown) may be provided after the gas-liquid separation. Cooling of the treatment liquid.

The liquid (treatment liquid) separated by the gas-liquid separator 11 is discharged from the treatment liquid discharge line 15. The discharged liquid can be subjected to various purification steps such as biological treatment or membrane separation treatment. Further, part of the treatment liquid obtained by the wet oxidation treatment is directly sent back to the drain before the wet oxidation treatment or to the drain at any position of the drain supply line, and then subjected to wet oxidation treatment. For example, the treatment liquid obtained by the wet oxidation treatment can be used as the dilution water for drainage to reduce the TOD concentration or the COD concentration of the drainage.

The gas system separated by the gas-liquid separator 11 is discharged to the outside through the gas discharge line 14. Alternatively, the discharged gas may be subjected to other steps.

In the wet oxidation treatment used in the present invention, a heat exchanger may be used in the heater and the cooler, and these may be used in combination as appropriate.

In the following, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples, and modifications of the embodiments are intended to be included in the technical scope of the present invention without departing from the scope of the invention. .

[Examples]

Hereinafter, the present invention will be more specifically described in terms of a catalyst preparation example, a comparative modulation example, an embodiment, and a comparative example, but the present invention is not limited thereto.

Hereinafter, a catalyst preparation example, a distribution state of an active ingredient in a comparative preparation example, and a method of measuring an average particle diameter are shown.

<Measurement of distribution state of active ingredient>

The ratio of active ingredients (% by mass) present in the surface layer of the catalyst from the surface of the carrier to the depth of 500 μm relative to the total amount of active components supported by the catalyst, and the catalyst in the catalyst cross section according to EPMA (electron probe microanalysis) The amount of the active ingredient in the surface layer portion was subjected to line analysis, and the ratio of the area of the catalyst to the depth of 500 μm in the area ratio was calculated and calculated.

Analytical device: EPM-810 manufactured by Shimadzu Corporation

X-ray beam diameter: 1μm

Acceleration voltage: 20kV

Sample current: 0.1μm

Sample scanning speed: 200 μm/min

<Measurement of Average Particle Size of Active Components>

The average particle diameter of the active component supported by the catalyst was determined by TPD analysis and measuring the amount of chemical adsorption by the CO pulse method.

Analytical device: BEL-CAT, a catalyst analysis device of Japan Bell Co., Ltd.

Analytical method: TPD (temperature desorption method)

Carrier gas: helium

Detector: TCD (thermal conduction detector)

Pretreatment temperature / time: 300 ° C x 15 minutes (hydrogen environment)

CO adsorption temperature: 100 ° C

Catalyst modulation example 1:

In the catalyst modulation, a pellet-shaped carrier of titanium oxide (titanium oxide) is used. The carrier had an average diameter of 5 mm, an average length of 6 mm, and a specific surface area of 41 m ² /g by the BET method, and the crystal structure of the titanium oxide of the shaped carrier was anatase. In order to allow the particles of the active ingredient Pt to be highly dispersed and supported on the surface layer portion of the carrier, the carrier is often shaken while being loaded with a liquid sprayed with an aqueous solution of an alkaline platinum conjugate aqueous solution of sodium carbonate, and then subjected to a hot air flow of 90 ° C. The mixture was dried for one hour while being rotated, and then subjected to a calcination treatment at 300 ° C for 3 hours using a hydrogen-containing gas to obtain a catalyst (A-1). The main component of the obtained catalyst (A-1) and the mass ratio were TiO ₂ : Pt = 99.75: 0.25. The distribution of Pt of the catalyst (A-1) (the proportion of Pt present at the position of the carrier surface to within 500 μm relative to the total content of Pt). The results of the EPMA investigation and the particle size of Pt were analyzed by TPD analysis. As shown in Table 1.

Catalyst modulation examples 2 to 5:

The carrier used in the catalyst modulation example 1 was used in both of the catalyst preparation examples 2 to 5. In the method of supporting the catalyst active component of the carrier, the catalysts (A-2 to A-5) described in Table 1 were prepared in the same manner as in the catalyst preparation example 1 except that some of the materials were changed.

. Catalyst Preparation Example 2 (A-2): A liquid in which sodium hydroxide was added to an aqueous solution of an alkaline bismuth solution was used in place of a liquid in which sodium carbonate was added to an aqueous solution of an alkaline platinum conjugate. The main component of the obtained catalyst (A-2) and the mass ratio were TiO ₂ :Ru = 99.5:0.5.

. Catalyst Preparation Example 3 (A-3): A liquid in which sodium carbonate was added to an aqueous solution of a basic palladium complex was used instead of a liquid in which sodium carbonate was added to an aqueous solution of an alkaline platinum complex. The main component of the obtained catalyst (A-3) and the mass ratio were TiO ₂ : Pd = 99.6: 0.4.

. Catalyst Preparation Example 4 (A-4): A liquid in which sodium carbonate was mixed with an aqueous solution of ruthenium nitrate and an aqueous solution of ruthenium chloride and ethanol to replace sodium chloride. The main component of the obtained catalyst (A-4) and the mass ratio were TiO ₂ :Pt:Ir=99.7:0.1:0.2.

. Catalyst Preparation Example 5 (A-5): A liquid in which a sodium chloride aqueous solution and an aqueous solution of platinum nitrate and acetone were mixed to replace a solution in which an aqueous alkaline platinum solution was added with sodium carbonate was used. The main component of the obtained catalyst (A-5) and the mass ratio were TiO ₂ :Au:Pt=99.6:0.2:0.2.

Distribution of active ingredients of the catalysts (A-1) to (A-5) (proportion of active ingredients present on the surface of the carrier to a position within 500 μm relative to the total content of the active ingredients) as a result of EPMA investigation and active ingredients The results of the TPD analysis of the particle size are shown in Table 1.

Comparison Modulation Example 1:

The same carrier as the catalyst preparation example 1 was added to the powder after pulverization. The platinum nitrate aqueous solution was mixed, and then dried to form the same shape (a pellet having an average diameter of 5 mm and an average length of 6 mm), followed by firing at 550 ° C for 3 hours in the air, and then using a hydrogen-containing gas. The firing treatment was carried out at 300 ° C for 3 hours to obtain a catalyst (A-6). The main component of the obtained catalyst (A-6) and the mass ratio were TiO ₂ : Pt = 99.75: 0.25. Further, the distribution of Pt of the catalyst (A-6) (the proportion of Pt present in the position of the carrier surface to within 500 μm with respect to the total content of Pt) was investigated by the EPMA investigation and the particle diameter of Pt by TPD analysis. The results are shown in Table 1.

Catalyst modulation examples 6 to 8:

In the catalyst preparation examples 6 to 8, a pellet-shaped carrier of an oxide of titanium and a composite oxide of titanium and zirconium was used. The carrier had an average diameter of 4 mm, an average length of 5 mm, and a specific surface area of 46 m ² /g by the BET method, and the crystal structure of the oxide of titanium contained in the shaped carrier was anatase. Then, the carrier contained the active ingredient in the same manner as in the catalyst preparation example 1, and the catalysts B-1 to B-3 were obtained. (At the same time, in the catalyst preparation example 6, a liquid in which sodium carbonate is added to the aqueous solution of the alkaline platinum complex; in the catalyst preparation example 7, a liquid in which sodium hydroxide is added to the aqueous alkaline solution is used; In the medium preparation example 8, a liquid in which sodium carbonate is added to an aqueous solution of a basic palladium complex is used.) The main component of the obtained catalyst B-1 and the mass ratio are TiO ₂ : ZrO ₂ : Pt = 64.8: 34.9: 0.3; The main component of the medium B-2 and the mass ratio are TiO ₂ :ZrO ₂ :Ru=64.6:34.8:0.6; the main component of the catalyst B-3 and the mass ratio is TiO ₂ :ZrO ₂ :Pd=64.7:34.8 :0.5. Further, the distribution of the active ingredients of the catalysts B-1 to B-3 (the ratio of the active ingredients present on the surface of the carrier to the position within 500 μm with respect to the total content of the active ingredients) is the result of the EPMA investigation and the particles of the active ingredient. The results of the TPD analysis are shown in Table 2.

Catalyst modulation examples 9 to 11

In the catalyst preparation examples 9 to 11, a pellet-shaped carrier of an oxide of titanium, an oxide of iron, and a composite oxide of titanium and iron was used. The carrier had an average diameter of 4 mm, an average length of 5 mm, and a specific surface area of 52 m ² /g by the BET method, and the crystal structure of the oxide of titanium contained in the shaped carrier was anatase. Then, the carrier contained the active ingredient in the same manner as in Catalyst Preparation Example 1, to obtain catalysts C-1 to C-3. (At the same time, in the catalyst preparation example 9, a liquid in which sodium carbonate is added to the aqueous solution of the alkaline platinum complex is used; in the catalyst preparation example 10, a liquid in which sodium hydroxide is added to the aqueous solution of the alkaline solution is used; In the medium preparation example 11, a liquid in which sodium carbonate was added to an aqueous solution of a basic palladium complex was used.) The main component of the obtained catalyst C-1 and the mass ratio were TiO ₂ :Fe ₂ O ₃ : Pt = 64.8: 34.9: 0.3. The main component of the catalyst C-2 and the mass ratio is TiO ₂ :Fe ₂ O ₃ :Ru=64.6:34.8:0.6; the main component of the catalyst C-3 and the mass ratio is TiO ₂ :Fe ₂ O ₃ : Pd = 64.7: 34.8: 0.5. Further, the distribution of the active ingredients of the catalysts C-1 to C-3 (the ratio of the active ingredients present at a position on the surface of the carrier to within 500 μm with respect to the total content of the active ingredients) is the result of the EPMA investigation and the particles of the active ingredient. The results of the TPD analysis are shown in Table 3.

Example 1

Using the apparatus shown in Fig. 1, the treatment was carried out for 150 hours under the following conditions. 1.0 L of the catalyst (A-1) was filled in the inside of the reaction column 1 (a cylindrical shape having a diameter of 26 mm and a length of 3000 mm). The wastewater to be treated is discharged from the chemical plant with acetic acid as the main drainage, and the COD (Cr) is 21 g/L.

This drain water is supplied to the drain supply pump 5 through the drain supply line 6, and is boosted and fed at a flow rate of 1.5 L/h, and then heated to 230 ° C by the heater 3 and supplied from the bottom of the reaction tower 1. The air is supplied from the oxygen-containing gas supply line 8, and after being pressurized by the compressor 7, the flow rate is adjusted by the oxygen-containing gas flow rate adjusting valve 9 so that O ₂ /COD (Cr) = 1.5 (the amount of oxygen in the supply gas / drainage) The required amount of chemical oxygen is 1.5), and the drain is mixed before the heater 3. Further, in the reaction column 1, the treatment is carried out in a gas-liquid upward cocurrent flow. In the reaction tower 1, the electric heater 2 is used to maintain the drainage temperature at a temperature of 230 ° C and to perform oxidation. Decomposition processing. The obtained treatment liquid is sent to the gas-liquid separator 11 through the treatment liquid line 10 to separate the gas and liquid. At this time, the liquid level is detected by the liquid level controller LC in the gas-liquid separator 11, and the liquid level is controlled by the liquid level control valve 13 to maintain the fixed liquid level. The pressure control valve 12 detects the pressure by the pressure controller PC and regulates the pressure to maintain at 5 MPa (Gauge). The treatment results of the obtained drainage are shown in Table 4.

Examples 2 to 5 and Comparative Examples

Drainage treatment was carried out in the same manner as in Example 1 except that the catalysts were each changed to A-2 to A-6. The results are shown in Table 4.

Example 6

Using the apparatus shown in Fig. 1, the treatment was carried out for 100 hours under the following conditions. 1.0 L of the catalyst (B-1) was filled in the inside of the reaction column 1 (a cylindrical shape having a diameter of 26 mm and a length of 3000 mm). The wastewater to be treated is discharged from the chemical plant with acetic acid as the main drainage, and the COD (Cr) is 23 g/L.

This drain water is supplied to the drain supply pump 5 through the drain supply line 6, and is boosted and fed at a flow rate of 2.1 L/h, and then heated to 250 ° C by the heater 3 and supplied from the bottom of the reaction column 1. The air is supplied from the oxygen-containing gas supply line 8, and after being pressurized by the compressor 7, the flow rate is adjusted by the oxygen-containing gas flow rate adjusting valve 9 so that O ₂ /COD (Cr) = 1.2 (the amount of oxygen in the supply gas / drainage) The required amount of chemical oxygen is 1.2), and the drain is mixed before the heater 3. Further, in the reaction column 1, the treatment is carried out in a gas-liquid upward cocurrent flow. In the reaction tower 1, the electric heater 2 is used to maintain the drainage temperature at a temperature of 250 ° C and to perform oxidation. Decomposition processing. The obtained treatment liquid is sent to the gas-liquid separator 11 through the treatment liquid line 10 to separate the gas and liquid. At this time, the liquid level is detected by the liquid level controller LC in the gas-liquid separator 11, and the liquid level is controlled by the liquid level control valve 13 to maintain the fixed liquid level. The pressure control valve 12 detects the pressure by the pressure controller PC and regulates the pressure to maintain at 5 MPa (Gauge). The treatment results of the obtained drainage are shown in Table 5.

Examples 7 and 8

Drainage treatment was carried out in the same manner as in Example 6 except that the catalysts were changed to B-2 and B-3, respectively. The results are shown in Table 5.

Example 9

Using the apparatus shown in Fig. 1, the treatment was carried out for 120 hours under the following conditions. 1.0 L of the catalyst (B-1) was filled in the reaction column 1 (a cylindrical shape having a diameter of 26 mm and a length of 3000 mm). The drainage for treatment is discharged from the chemical plant with sodium acetate as the main drainage, and the COD (Cr) is 19 g/L.

This drain water is supplied to the drain supply pump 5 through the drain supply line 6, and is boosted and fed at a flow rate of 1.6 L/h, and then heated to 220 ° C by the heater 3 and supplied from the bottom of the reaction tower 1. The air is supplied from the oxygen-containing gas supply line 8, and after being pressurized by the compressor 7, the flow rate is adjusted by the oxygen-containing gas flow rate adjusting valve 9 so that O ₂ /COD (Cr) = 1.5 (the amount of oxygen in the supply gas / drainage) The required amount of chemical oxygen is 1.5), and the drain is mixed before the heater 3. Further, in the reaction column 1, the treatment is carried out in a gas-liquid upward cocurrent flow. In the reaction tower 1, the electric heater 2 is used to maintain the drainage temperature at a temperature of 220 ° C and to perform oxidation. Decomposition processing. The obtained treatment liquid is sent to the gas-liquid separator 11 through the treatment liquid line 10 to separate the gas and liquid. At this time, the liquid level is detected by the liquid level controller LC in the gas-liquid separator 11, and the liquid level is controlled by the liquid level control valve 13 to maintain the fixed liquid level. The pressure control valve 12 detects the pressure by the pressure controller PC and regulates the pressure to maintain at 5 MPa (Gauge). The treatment results of the obtained drainage are shown in Table 6.

Examples 10 and 11

Drainage treatment was carried out in the same manner as in Example 9 except that the catalysts were changed to C-2 and C-3, respectively. The results are shown in Table 6.

1‧‧‧Reaction tower

2‧‧‧Electric heater

3‧‧‧heater

4‧‧‧ cooler

5‧‧‧ pump

6‧‧‧Drainage supply line

7‧‧‧Compressor

8‧‧‧ gas supply line

9‧‧‧Gas flow adjustment valve

10‧‧‧Processing fluid pipeline

11‧‧‧ gas-liquid separator

12‧‧‧ Pressure Control Valve

13‧‧‧liquid level control valve

14‧‧‧ gas discharge line

15‧‧‧Processing fluid discharge line

LC‧‧‧ level controller

PC‧‧‧ pressure controller

Fig. 1 is a view showing one of the performances of the apparatus for treating a wet oxidation treatment in the present invention.

1‧‧‧Reaction tower

2‧‧‧Electric heater

3‧‧‧heater

4‧‧‧ cooler

5‧‧‧ pump

6‧‧‧Drainage supply line

7‧‧‧Compressor

8‧‧‧ gas supply line

9‧‧‧Gas flow adjustment valve

10‧‧‧Processing fluid pipeline

11‧‧‧ gas-liquid separator

12‧‧‧ Pressure Control Valve

13‧‧‧liquid level control valve

14‧‧‧ gas discharge line

15‧‧‧Processing fluid discharge line

LC‧‧‧ level controller

PC‧‧‧ pressure controller

Claims (8)

A catalyst for drainage treatment, which is a catalyst used in wet oxidation treatment of drainage, which uses a noble metal as an active component, and a carrier supporting the active component contains at least one selected from the group consisting of iron, titanium, lanthanum, aluminum, and zirconium. a compound of an element in the group, wherein at least 70% by mass of the active ingredient supported by the carrier is present at a position within 500 μm from the surface of the carrier, and the active particle has an average particle diameter of 0.5 to 20 nm, wherein the catalyst It is produced by a method comprising the steps of: adding at least one selected from the group consisting of sodium carbonate, sodium hydroxide, ethanol and acetone to an aqueous solution of the active ingredient, and shaking the carrier frequently, and spraying the carrier Aqueous solution. The catalyst according to claim 1, wherein the active ingredient is at least one selected from the group consisting of silver, gold, platinum, palladium, ruthenium, osmium and iridium, or a compound containing the noble metal. The catalyst according to claim 1 or 2, wherein the loading amount of the active ingredient is 0.07 to 0.7% by mass based on the metal. The catalyst of claim 1, wherein the carrier is a combination of an oxide of titanium and a composite oxide of titanium and zirconium; a combination of an oxide of titanium and an oxide of iron and a composite oxide of titanium and iron; And any of the oxides of titanium. The catalyst according to claim 1, wherein the carrier has a micropore volume of from 0.20 to 0.50 ml/g. The catalyst according to claim 1, wherein the carrier has a specific surface area of 20 to 70 m ² /g. A method of treating a wastewater by wet-oxidizing a drain using a catalyst according to any one of claims 1 to 6. The method for wastewater treatment according to claim 7, wherein the step of filling the above-mentioned coal into the reaction tower is such that the space velocity between the catalyst layers is 0.1 to 10 hr ^-1 and the theoretical oxygen requirement is 0.5 to 3.0 times of the oxygen-containing gas is heated together with the drain water and supplied to the reaction column, and the reaction tower is heated to 80 to 370 ° C, and the drain water is subjected to cerium oxide decomposition treatment via a catalyst, and the obtained treatment liquid is subjected to gas-liquid separation.