Particulate water-insoluble inorganic material containing silver oxide and ruthenium oxide

Abstract

A method for producing a particulate water-insoluble inorganic material comprising silver oxide and ruthenium oxide, and a preparation containing water, particles of the water-insoluble inorganic material, at least one silver oxide precursor, and at least one ruthenium oxide precursor, by drying and thermal decomposition treatment carried out in a non-reducing atmosphere.

Description

[Technical Field]

[0001] The present invention relates to a particulate, water-insoluble inorganic material comprising silver oxide and ruthenium oxide, which are noble metal oxides, and to an efficient method for producing the same.

[0002] The objective of the present invention was to provide a novel antibacterial material that can be produced simply and efficiently.

[0003] This problem can be solved by providing a product in the form of a particulate water-insoluble inorganic material comprising silver oxide (Ag2O) and ruthenium oxide (RuO2). To avoid misunderstanding, the term “water-insoluble” as used in this context should not be understood in an absolute sense, but rather in a practical sense, i.e., a water solubility of less than 0.01 g per liter of water at 20°C. The water-insoluble inorganic material (the water-insoluble inorganic material itself) is sparingly soluble, i.e., a high-melting-point material, i.e., a material that does not melt at temperatures below the application temperature of the product according to the present invention, e.g., 1000°C. The water-insoluble inorganic material (such a water-insoluble inorganic material) is preferably selected from the group consisting of aluminum nitride, titanium nitride, silicon nitride, corundum, anatase-type titanium dioxide, rutile-type titanium dioxide, calcined silica, precipitated silica, sodium aluminum silicate, zirconium silicate, zeolite, hydrotalcite, and gamma-oxyhydroxide.

[0004] The particulate water-insoluble inorganic material according to the present invention, comprising silver oxide and ruthenium oxide, is hereinafter simply referred to as "the product according to the present invention." The silver-plus-ruthenium weight ratio formed by silver oxide and ruthenium oxide can be in the range of, for example, 0.1 to 50 wt.% (weight%), preferably 1 to 40 wt.%, and at the same time, a silver:ruthenium weight ratio in the range of, for example, 1 to 2000 parts by weight of silver : 1 part by weight of ruthenium is dominant.

[0005] The particulate water-insoluble inorganic material or the particles of the water-insoluble inorganic material themselves are carrier materials (carrier particles) for silver oxide and ruthenium oxide that do not contain noble metal oxides themselves; that is, in the product according to the present invention, the particulate water-insoluble inorganic material functions as a carrier for silver oxide and ruthenium oxide. The product according to the present invention may contain one or more carrier materials, and usually and also preferably only one carrier material is present in the product according to the present invention.

[0006] The product according to the present invention has an average particle size (d50) in the range of 0.3 to 100 μm, and for example, 1 to 2000 μm. 2 They can have a BET surface area in the range of / g. They can also have a pore volume in the range of, for example, 0.5 to 10 mL / g.

[0007] As used herein, the term “average particle size” refers to the volume-average primary particle size (d50) that can be measured by laser diffraction. In this case, the equivalent circular area diameter (ECAD) can be advantageously used as a measure of particle size (see RENLIANG XU ET AL: “Comparison of sizing small particles using different technologies,” POWDER TECHNOLOGY, ELSEVIER, BASEL(CH), vol.132, no.2-3, June 24, 2003 (06-24-2003), pages 145-153). Laser diffraction measurements can be performed according to a wet measurement method using a corresponding particle size analyzer, for example, a Mastersizer 3000 or Mastersizer 2000 from Malvern Instruments. In the wet measurement method, the particulate sample can be dispersed in ethanol by ultrasound as part of the sample preparation.

[0008] As used herein, the term "BET surface area" refers to the specific surface area that can be determined by BET measurement in accordance with DIN ISO 9277:2014-01 (Chapter 6.3.1, static-volumetric measurement method, gas used: nitrogen).

[0009] In this specification, the term "pore volume" is used. Pore volume can be determined by mercury porosimetry according to DIN ISO 15901-1:2016 (sample mass 30 mg, mercury surface tension 0.48 N / m, mercury contact angle 141.3°, instrument: Porotec Pascal 140+440, measurement method: scan, initial intrusion pressure 0.0128 MPa, dilatometer: powder, small volume, sample preparation: 8 hours under vacuum at 110°C).

[0010] The product according to the present invention comprises particles of a water-insoluble inorganic material containing silver oxide and ruthenium oxide in amounts ranging from 90 to 100 wt.% or 95 to 100 wt.% and particularly 100 wt.%. Possible proportions not exceeding 10 wt.% or 5 wt.% can be formed by particles of the water-insoluble inorganic material that do not contain the corresponding noble metal oxide, ruthenium oxide particles and / or silver oxide particles. In other words, the product according to the present invention may consist of particles of a water-insoluble inorganic material containing 90 to 100 wt.% or 95 to 100 wt.% silver oxide and ruthenium oxide, and particles of the water-insoluble inorganic material that do not contain the corresponding noble metal oxide, ruthenium oxide particles and / or silver oxide particles in amounts of 0 to 10 wt.% or 0 to 5 wt.% such that the total wt.% is 100 wt.%. Aside from the water-insoluble inorganic material particles comprising silver oxide and ruthenium oxide, and the components constituting 0-10 wt.% and 0-5 wt.% respectively, the product according to the present invention contains no other intentionally added materials or substances.

[0011] Silver oxide and ruthenium oxide can be present on the inner surface (pores and / or cavities) and / or outer surface of carrier particles of water-soluble inorganic materials, thereby forming, for example, discontinuous layers and / or small silver oxide or ruthenium oxide particles (silver oxide or ruthenium oxide islands). Scanning transmission electron microscopy may be a suitable method for observing such morphological properties. Silver oxide and ruthenium oxide are statistically distributed, and both noble metal oxides are at least partially in contact with each other. It will be apparent to those skilled in the art that the silver oxide and ruthenium oxide in the product according to the present invention may also contain small amounts, practically negligible, of other silver forms (silver species) and other ruthenium forms (ruthenium species), such as elemental metallic silver or elemental metallic ruthenium and / or silver(I) compounds other than silver oxide or ruthenium compounds other than ruthenium oxide, such as halides and / or sulfides. Such forms may be unintentionally and inevitably generated as small amounts of impurities during or after the production of the product according to the present invention, for example, during storage, use or further processing.

[0012] The present invention also relates to a method for producing the products according to the present invention. In another view, this method can also be understood as a method for providing the corresponding particulate, water-insoluble inorganic material comprising silver oxide and ruthenium oxide.

[0013] In the method according to the present invention, the product according to the present invention can be obtained by drying and thermal decomposition treatment of a preparation containing water, particles of the corresponding water-insoluble inorganic material described above, at least one silver oxide precursor, and at least one ruthenium oxide precursor, under a non-reducing atmosphere. The thermal decomposition treatment is performed at a temperature above the thermal decomposition temperature. The thermal decomposition temperature is the minimum material temperature that ensures the thermal decomposition of at least one silver oxide precursor and at least one ruthenium oxide precursor under a non-reducing atmosphere to form silver oxide and ruthenium oxide.

[0014] As used herein, the term “non-reducing atmosphere” refers to an oxidizing or inert atmosphere. The term “oxidizing atmosphere” refers to an atmosphere consisting of an oxidizing gas, such as oxygen, air, or a mixture of oxygen and one or more inert gases such as nitrogen, argon, and / or carbon dioxide, where the volume fraction of oxygen in such a gas mixture containing an inert gas may be, for example, in the range of 10% to 30% by volume. The term “inert atmosphere” refers to an atmosphere consisting of one or more inert gases such as nitrogen, argon, and / or carbon dioxide.

[0015] In the method according to the present invention, the above particles of a water-insoluble inorganic material (i.e., the corresponding water-insoluble inorganic material), a silver oxide precursor, and a ruthenium oxide precursor are used.

[0016] As already mentioned, the aforementioned particles of water-insoluble inorganic material are preferably particles selected from the group consisting of aluminum nitride, titanium nitride, silicon nitride, corundum, anatase-type titanium dioxide, rutile-type titanium dioxide, calcined silicon dioxide, precipitated silicon dioxide, sodium aluminum silicate, zirconium silicate, zeolite, hydrotalcite, and gamma-oxyhydroxide. In other words, the particles consist of materials selected from the group consisting of aluminum nitride, titanium nitride, silicon nitride, corundum, anatase-type titanium dioxide, rutile-type titanium dioxide, calcined silica, precipitated silica, sodium aluminum silicate, zirconium silicate, zeolite, hydrotalcite, and gamma-oxyhydroxide. The corresponding particles of titanium nitride, corundum, anatase-type or rutile-type titanium dioxide, calcined or precipitated silica, and gamma-oxyhydroxide are preferred.

[0017] Preferably, the particles of the aforementioned water-insoluble inorganic material have an average particle size (d50) in the range of 0.3 μm to 40 μm and 1 to 2000 μm. 2 They have a BET surface area in the range of / g. They can also have a pore volume in the range of 0.5 to 10 mL / g.

[0018] The silver oxide precursor and ruthenium oxide precursor used in the method according to the present invention are silver and ruthenium compounds that can be thermally decomposed under a non-reducing atmosphere to form silver oxide and ruthenium oxide, respectively.

[0019] All silver compounds that can be thermally decomposed in a non-reducing atmosphere to form silver oxide can be thermally decomposed in an oxidizing atmosphere in the method according to the present invention, and in that method, they can be thermally decomposed to form silver oxide. Those skilled in the art can easily determine such suitability of a silver compound for thermal decomposition to form silver oxide in an oxidizing atmosphere, for example, by using thermogravimetric analysis in an oxidizing atmosphere. Examples of silver compounds suitable as silver oxide precursors in this context include silver acetate and silver nitrate.

[0020] Some silver compounds that can be thermally decomposed to form silver oxide under a non-reducing atmosphere can be thermally decomposed even under an inert atmosphere by the method according to the present invention, and in that method, they can be thermally decomposed to form silver oxide. Those skilled in the art can easily determine such suitability of a silver compound for thermal decomposition to form silver oxide under an inert atmosphere, for example, by using thermogravimetric analysis under an inert gas atmosphere. An example of a silver compound suitable as a silver oxide precursor in this context is silver nitrate.

[0021] All ruthenium compounds that can be thermally decomposed under a non-reducing atmosphere to form ruthenium oxide can be thermally decomposed under an oxidizing atmosphere in the method according to the present invention, and in that method, they can be thermally decomposed to form ruthenium oxide. Those skilled in the art can easily determine such suitability of a ruthenium compound for thermal decomposition to form ruthenium oxide under an oxidizing atmosphere, for example, by using thermogravimetric analysis under an oxidizing atmosphere. Examples of ruthenium compounds suitable in this context include ruthenium nitrosylnitrate, ruthenium oxalate, ruthenium acetate, and especially ruthenium nitrosyloxalate.

[0022] Some ruthenium compounds that can be thermally decomposed to form ruthenium oxide in a non-reducing atmosphere can be thermally decomposed even in an inert atmosphere in the method according to the present invention, and in that method, they can be thermally decomposed to form ruthenium oxide. Those skilled in the art can easily determine such suitability of ruthenium compounds for thermal decomposition to form ruthenium oxide in an inert atmosphere, for example, by using thermogravimetric analysis in an inert gas atmosphere. Examples of ruthenium compounds that are suitable in the context as ruthenium oxide precursors include ruthenium nitrosyl nitrate, ruthenium oxalate, and particularly ruthenium nitrosyl oxalate.

[0023] For example, in the method according to the present invention, a combination of silver nitrate and ruthenium nitrosyl oxalate or ruthenium nitrosyl nitrate can be used, and preferably, it can be thermally decomposed in an oxidizing atmosphere.

[0024] The production method according to the present invention includes continuously providing a preparation containing water, particles of a water-insoluble inorganic material, at least one silver oxide precursor, and at least one ruthenium oxide precursor, and drying and thermally decomposing the preparation, which is carried out in a non-reducing atmosphere. The drying and thermal decomposition processes can be carried out as sequential or simultaneous steps.

[0025] In a first embodiment, the method according to the present invention (1) providing a preparation containing water, particles of a water-insoluble inorganic material, at least one silver oxide precursor, and at least one ruthenium oxide precursor; (2) drying the preparation provided in step (1); (3) thermally decomposing the dried preparation obtained after completion of step (2) carried out in a non-reducing atmosphere; and includes the above continuous steps.

[0026] In a second embodiment where step (2) and step (3) are carried out together, the method according to the present invention (1) Providing a preparation containing water, particles of a water-insoluble inorganic material, at least one silver oxide precursor and at least one ruthenium oxide precursor; (2 + 3) Drying and pyrolyzing the preparation provided in step (1) under a non-reducing atmosphere; comprises the following consecutive steps.

[0027] In step (1) according to both embodiments of the method according to the invention, a preparation containing water, particles of a water-insoluble inorganic material, at least one silver oxide precursor and at least one ruthenium oxide precursor is provided. The preparation may be in the form of an aqueous suspension or in the form of impregnated particles. The two forms, (a) aqueous suspension or (b) impregnated particles, differ respectively in the presence or absence of an aqueous liquid between the particles. In the case of an aqueous suspension, an aqueous liquid is present between the particles, which has the appearance of a dry or freely flowing powder, and the aqueous liquid does not form the components of the particles or apply to the case of impregnated particles where it is inside the particles.

[0028] The aqueous suspension can be prepared by adding particles of a water-insoluble inorganic material to an aqueous solution of at least one silver oxide precursor and at least one ruthenium oxide precursor and suspending them therein.

[0029] However, the silver oxide precursor and the ruthenium oxide precursor are preferably added, in each case as an aqueous solution, simultaneously or in any order (with time delays, overlapping, alternately or continuously), to the aqueous suspension initially filled with particles of the water-insoluble inorganic material. It is particularly preferred that aqueous solutions of both noble metal precursors (an aqueous solution of at least one silver oxide precursor and an aqueous solution of at least one ruthenium oxide precursor) are added to the aqueous suspension initially filled with particles of the water-insoluble inorganic material. Generally, the mixing is carried out, during and also after the addition, for example by stirring.

[0030] The weight ratio of the particles of the water-insoluble inorganic material in the aqueous suspension provided in step (1) of the method according to the invention can be in the range of, for example, 5 wt.% to 30 wt.%.

[0031] The weight percentage of the precious metals formed from silver and ruthenium in the aqueous suspension provided in step (1) of the method according to the present invention may be in the range of, for example, 1 wt.% to 20 wt.%. The aqueous suspension prepared in step (1) of the method according to the present invention is characterized in that the weight ratio of the two precious metals is in the range of, for example, 1 part by weight to 2000 parts by weight of silver:1 part by weight of ruthenium, and is generally significantly biased towards silver.

[0032] In addition to particles of water-insoluble inorganic material, a silver oxide precursor, and a ruthenium oxide precursor, the aqueous suspension provided in step (1) of the method according to the present invention generally consists only of water and optionally the corresponding acid from the noble metal oxide precursor.

[0033] It is preferable to produce the preparation in the form of impregnated particles. This can be done by impregnating particles of a water-insoluble inorganic material with an aqueous solution of at least one silver oxide precursor and at least one ruthenium oxide precursor in a manner conventional in the art. The impregnation method can be carried out once or repeatedly, in the latter case, a drying step is performed between each impregnation step.

[0034] The impregnation method must be carried out in such a way that no aqueous suspension is formed, i.e., no thin slurry, pulp, paste, or kneaded mass is produced, but rather the impregnated particles are formed in the form of a macroscopically homogeneous and freely flowable powder. In other words, the volume of the aqueous solution must be sufficiently small and selected so that the particles of the water-insoluble inorganic material are suitable for impregnation with it. When impregnation is performed, it is appropriate to allow sufficient time for the particles of the water-insoluble inorganic material and the aqueous solution to mix. For example, it may be appropriate to mix for a sufficiently long time, especially until a macroscopically homogeneous state of the mixed material is achieved. The volume of the aqueous solution can be selected by adjusting the specific concentration of the noble metal oxide precursor with respect to the number of particles of the water-insoluble inorganic material that are brought into contact with the aqueous solution and the absorption behavior of the particles of the water-insoluble inorganic material in the aqueous solution. If the volume is too large, the aforementioned undesirable slurry, pulp, kneaded mass, or paste will be produced. Those skilled in the art can easily determine the absorption behavior of relevant particles of a water-insoluble inorganic material in a relevant aqueous solution in the application of laboratory tests, and thus determine the upper limit of the number of liters of aqueous solution per kilogram of particles of the water-insoluble inorganic material without impairing its free flowability.

[0035] The weight percentage of water-insoluble inorganic material particles provided in step (1) of the method according to the present invention may be, for example, in the range of 50 wt.% to 90 wt.%.

[0036] The weight ratio of the precious metals formed from silver and ruthenium in the impregnated particles provided in step (1) of the method according to the present invention may be in the range of, for example, 3 wt.% to 20 wt.%. The impregnated particles provided in step (1) of the method according to the present invention are characterized in that the weight ratio of the two precious metals is in the range of, for example, 1 part by weight to 2000 parts by weight of silver:1 part by weight of ruthenium, and is generally significantly biased towards silver.

[0037] In addition to water-insoluble inorganic material particles and noble metal oxide precursors, the impregnated particles provided in step (1) of the method according to the present invention generally contain only water and optionally the corresponding acid from the noble metal oxide precursor. The water content of the impregnated particles provided in step (1) of the method according to the present invention may be in the range of, for example, 7 wt.% to 35 wt.%.

[0038] In step (2) according to the first embodiment of the method according to the present invention, the preparation provided in step (1) is dried, i.e., water and any other volatile substances that may be present are removed.

[0039] In the case of an aqueous suspension, it is evaporated to dryness. Advantageously, the aqueous suspension is stirred during concentration, for example by stirring and / or shaking and / or rotating, i.e., by rotating the vessel or container containing the aqueous suspension. Generally, heating and / or negative pressure is applied during concentration to remove water and any other volatile substances that may be present. During concentration, the work can be carried out at a temperature in the range of, for example, 40°C to 110°C. The material obtained after dryness has been achieved can be ground if necessary.

[0040] In the case of impregnated particles, these can be dried in a furnace at temperatures ranging from 40°C to 110°C, for example. Negative pressure can be applied to aid in this process. The dried material can be crushed as needed.

[0041] In step (3) according to the first embodiment of the method according to the present invention, the noble metal oxide precursor is thermally decomposed to form silver oxide and ruthenium oxide. For this purpose, the optionally pulverized material obtained after the completion of step (2) is subjected to thermal decomposition under a non-reducing atmosphere. For this purpose, the material can be heated, either in a stationary or moving state, to a thermal decomposition temperature, for example, in the range of 120°C to 900°C, preferably 150°C to 400°C, in a stationary furnace, fluidized bed reactor, or rotary kiln. During step (3), the furnace chamber is conveniently flushed with a non-reducing gas or a gas mixture, and the gas flow may also serve to remove gaseous decomposition products. The non-reducing atmosphere may also be reduced under reduced pressure.

[0042] In a combined step (2+3) according to the first variation of the second embodiment of the method according to the present invention, the preparation provided in step (1) is dried and pyrolyzed in a non-reducing atmosphere. The preparation provided in step (1) can be passed through a furnace temperature profile including a drying temperature and a higher pyrolyzed temperature, either in a moving or stationary state. This can be achieved by passing it through a furnace having a temperature gradient including a drying temperature and a pyrolyzed temperature, or by passing it through a furnace with a time-controlled heating or temperature program that first ensures a drying temperature, and then a pyrolyzed temperature. Examples of usable furnace types include stationary furnaces, fluidized bed reactors, and rotary kilns. The preparation provided in step (1) can be used in the form of an aqueous suspension, but it is preferable to use the preparation provided in step (1) in the form of impregnated particles.

[0043] In either case, the preparation provided in step (1) is first dried, i.e., water and any other volatile substances, if any, are removed. If the preparation is provided in step (1) as an aqueous suspension, the preparation is evaporated to dryness. During concentration, the work can be carried out at a drying temperature in the range of, for example, 40°C to 110°C. If the preparation is provided in step (1) in the form of impregnated particles, the preparation can also be dried at a drying temperature in the range of, for example, 40 to 110°C. After drying is complete, the noble metal oxide precursor is thermally decomposed to form silver oxide and ruthenium oxide by immediately further heating to a thermal decomposition temperature in the range of, for example, 120 to 900°C, preferably 150 to 400°C, without intermediate cooling; i.e., the dried material undergoes a thermal decomposition treatment. This drying and the subsequent thermal decomposition are carried out in a non-reducing atmosphere.

[0044] Furthermore, in a combined step (2+3) according to a second variation of the second embodiment of the method according to the present invention, the preparation provided in step (1) is dried and thermally decomposed in a non-reducing atmosphere. The preparation provided in step (1) can be exposed in a furnace, either in a moving or stationary state, to a thermal decomposition temperature in the range of, for example, 120°C to 900°C, preferably 150°C to 400°C. Examples of usable furnace types include a stationary furnace, a fluidized bed reactor, and a rotary kiln. The preparation provided in step (1) can be used in the form of an aqueous suspension, but it is preferable to use the preparation provided in step (1) in the form of impregnated particles. The noble metal oxide precursor is thermally decomposed to form silver oxide and ruthenium oxide. Drying and thermal decomposition are actually carried out in parallel. The work is carried out in a non-reducing atmosphere.

[0045] The product according to the present invention is obtained by step (3) according to the first embodiment of the method according to the present invention, or by step (2+3) according to both variations of the second embodiment, and optionally after the completion of subsequent grinding and / or classification.

[0046] The product according to the invention, namely the particulate water-insoluble inorganic material comprising silver oxide and ruthenium oxide, is characterized by a dark or black color, for example in the range of 35 to 45, of the corresponding low lightness L * which can be a hindrance for some applications. The lightness L * is the CIEL * a * b * color space (DIN EN ISO / CIE 11664-4:2020-03) in a specific * L * and the spectrophotometric measurement of the product according to the invention can be carried out on a sample poured into a colorless glass container up to a filling height of 1 cm through the flat glass bottom of the glass container arranged on the measuring head of the spectrophotometer used.

[0047] If desired, the product according to the invention can be further processed into a whitened particulate material having a lightness L * in the range of, for example, 50 to 85. For the purpose of whitening, the product according to the invention can be brought into contact with at least one C1 - C4 alkoxide of aluminum, magnesium, calcium, silicon, zinc, zirconium, and / or titanium in the presence of at least a sufficient amount of water for the complete hydrolysis of the at least one C1 - C4 alkoxide. As described above, a whitened particulate material, namely a particulate material having a color, for example gray, with a lightness L * in the range of, for example, 50 to 85 can be formed. This whitened particulate material consists of the product according to the invention having at least a part of a solid thereon. Depending on the selection of the at least one C1 - C4 alkoxide, the solid is a solid selected from the group consisting of aluminum oxide, aluminum hydroxide, aluminum oxyhydroxide, magnesium oxide, magnesium hydroxide, magnesium oxyhydroxide, calcium oxide, calcium hydroxide, calcium oxyhydroxide, silicon dioxide, silica, zinc oxide, zinc hydroxide, zinc oxyhydroxide, zirconium dioxide, zirconium(IV) oxyhydrate, titanium dioxide, titanium(IV) oxyhydrate, and combinations thereof.

[0048] As described above, the optionally whitened products of the present invention are characterized by a particularly potent antimicrobial effect, which can be determined by conventional inhibition zone tests or by determining the minimum inhibitory concentration from the growth curve of microorganisms. In this regard, the present invention also relates to the use of the optionally whitened products of the present invention, which are provided as additives for antimicrobial treatment of metal surfaces, coatings such as varnishes and other paints, plaster, molding compounds, plastic materials in the form of plastic films, plastic parts or plastic fibers, textiles or textile utility products, synthetic resin products, ion exchange resins, silicone products, cellulosic products, foams, cosmetics, and many other things.

[0049] As described above, the selectively whitened product according to the present invention can also be used, for example, as a heterogeneous catalyst in the catalytic activity of hydroxyl radical formation in an aqueous medium that enables bacterial growth.

[0050] The product according to the present invention, which has been selectively whitened as described above, can be used as a dry powder for the above-mentioned applications. If appropriate or desired, it can be pre-adjusted with water to a desired moisture content or converted into an aqueous suspension. [Examples]

[0051] Reference Example 1 (Thermal decomposition preparation of particulate inorganic material containing 20.7 wt.% elemental silver and 1.3 wt.% elemental ruthenium): Aqueous solutions prepared from 52.4 g of silver nitrate aqueous solution (silver content 36.2 wt.%, 176.2 mmol of Ag) and 5.3 g of ruthenium nitrosylnitrate aqueous solution (ruthenium content 18.9 wt.%, 9.8 mmol of Ru) were added to 80 g of zeolite powder (beta zeolite, SAR 40 manufactured by PIDC) with shaking. The material was then dried in a drying oven at 105°C / 300 mbar. The material was then calcined in a tubular furnace in a forming gas atmosphere (5 vol% hydrogen / 95 vol% nitrogen) at 250°C for 5 hours and ground in an agate mortar. The silver content of the product (20.7 wt.%) and the ruthenium content (1.3 wt.%) (based on 0 wt.%) were determined using ICP-OES (inductively coupled plasma atomic emission spectrometry). XRD (X-ray diffraction) was used to confirm that the silver and ruthenium contained in the product were in their elemental form.

[0052] Example 2 of the present invention (thermal decomposition preparation of particulate inorganic material comprising 19 wt.% silver in the form of silver oxide and 1 wt.% ruthenium in the form of ruthenium oxide): An aqueous solution prepared from 26.2 g of silver nitrate aqueous solution (silver content 36.2 wt.%, 88.1 mmol of Ag), 2.6 g of ruthenium nitrosylnitrate aqueous solution (ruthenium content 18.9 wt.%, 4.9 mmol of Ru), and 3.2 g of water was added to 40 g of zeolite powder (Puralox® 100 / 150 UF, manufactured by Sasol) while shaking. The material was then dried in a drying oven at 105°C / 300 mbar for 5 hours. Next, the material was calcined in a tubular furnace at 250°C for 16 hours under an air atmosphere and then ground in an agate mortar. Products with a silver content of 18.7 wt.% and a ruthenium content of 1.0 wt.% (relative to 0 wt.% residual moisture) were determined by ICP-OES. Using XPS (X-ray photoelectron spectroscopy), it was confirmed that the silver and ruthenium contained in the product are corresponding metal oxides.

[0053] Example 3 (A test to compare the antibacterial effects of the products from Reference Example 1 and Example 2 according to the present invention): The antimicrobial effect can be analyzed, in particular, chemically. Chemical analysis involves determining the concentrations of hydrogen peroxide and other reactive oxygen forms produced by the product in the presence of oxygen and water, using UV / VIS spectroscopy.

[0054] The product to be analyzed is incubated in an acidic aqueous solution of iron(II) ions and xylenol orange dye. The reaction with the reactive oxygen form formed in situ produces iron(III) ions, which form a purple complex with the organic dye. The amount of radicals produced in μg / L units can be determined by photometric measurement of the concentration of the complex in the solution. To determine the radical concentration as accurately as possible, multiple dilutions of the hydrogen peroxide stock solution are analyzed similarly on the day of analysis to create a calibration curve.

[0055] For specific analysis, 50 mg of the product to be analyzed, 2.5 mL of 4 mM ammonium iron(II) sulfate solution, and 0.5 mL of 2.7 mM xylenol orange solution were placed in a volumetric flask. The sample volume was increased to 50 mL by adding distilled water and stirred at room temperature and 450 rpm for 55 minutes. After a 5 minute sedimentation time, the supernatant sample was filtered and the absorbance at 585 nm was determined. The absorbance of the sample was converted to the concentration of hydrogen peroxide using a calibration curve.

[0056] The radical concentration was calculated using the corresponding sample amounts of the product from Reference Example 1 or Example 2 according to the present invention. As a result, the value for the product from Reference Example 1 was 1157 μg / L, and the value for the product from Example 2 according to the present invention was 951 μg / L, which is an equivalent value.

Claims

1. A particulate, water-insoluble inorganic material containing silver oxide and ruthenium oxide.

2. The particulate water-insoluble inorganic material comprising silver oxide and ruthenium oxide according to claim 1, wherein the water-insoluble inorganic material is selected from the group consisting of aluminum nitride, titanium nitride, silicon nitride, corundum, anatase-type titanium dioxide, rutile-type titanium dioxide, calcined silica, precipitated silica, sodium aluminum silicate, zirconium silicate, zeolite, hydrotalcite, and gamma-oxyhydroxide.

3. The particulate water-insoluble inorganic material comprising silver oxide and ruthenium oxide according to claim 1 or 2, wherein the silver-plus-ruthenium weight ratio formed by the silver oxide and ruthenium oxide is in the range of 0.1 to 50 wt.%, and at the same time, a silver:ruthenium weight ratio in the range of 1 to 2000 parts by weight of silver:1 part by weight of ruthenium is predominant.

4. Average particle size (d50) in the range of 0.3 to 100 μm and 1 to 2000 μm ２ A particulate water-insoluble inorganic material comprising silver oxide and ruthenium oxide according to any one of claims 1 to 3, having a BET surface area in the range of / g.

5. A particulate water-insoluble inorganic material comprising silver oxide and ruthenium oxide according to any one of claims 1 to 4, comprising particles of a water-insoluble inorganic material comprising 90 to 100 wt.% of the silver oxide and ruthenium oxide, and 0 to 10 wt.% of the water-insoluble inorganic material that does not contain the corresponding noble metal oxide, ruthenium oxide particles and / or silver oxide particles.

6. A method for producing particulate water-insoluble inorganic material comprising silver oxide and ruthenium oxide according to any one of claims 1 to 5, by drying and thermal decomposition of a preparation containing water, particles of a corresponding water-insoluble inorganic material, at least one silver oxide precursor and at least one ruthenium oxide precursor under a non-reducing atmosphere.

7. The method according to claim 6, wherein the non-reducing atmosphere is an oxidizing or inert atmosphere.

8. The method according to claim 6 or 7, wherein the silver oxide precursor and the ruthenium oxide precursor are silver and ruthenium compounds that can be thermally decomposed in a non-reducing atmosphere to form silver oxide and ruthenium oxide, respectively.

9. The method according to any one of claims 6 to 8, wherein the non-reducing atmosphere is an oxidizing atmosphere, the at least one silver oxide precursor is selected from the group consisting of silver acetate and silver nitrate, and the at least one ruthenium oxide precursor is selected from the group consisting of ruthenium nitrosylnitrate, ruthenium oxalate, ruthenium acetate and ruthenium nitrosyloxalate.

10. The method according to any one of claims 6 to 8, wherein the non-reducing atmosphere is an inert atmosphere, the at least one silver oxide precursor is silver nitrate, and the at least one ruthenium oxide precursor is selected from the group consisting of ruthenium nitrosylnitrate, ruthenium oxalate, and ruthenium nitrosyloxalate.

11. (1) A step of providing the preparation, (2) A step of drying the preparation provided in step (1), (3) A step of thermally decomposing the dried preparation obtained after the completion of step (2) in a non-reducing atmosphere, This includes a series of steps, or (1) A step of providing the preparation, (2+3) A step of drying and thermally decomposing the preparation provided in step (1) under a non-reducing atmosphere, The method according to any one of claims 6 to 10, comprising the following continuous steps.

12. The method according to any one of claims 6 to 11, wherein the preparation is an aqueous suspension or impregnated particles.

13. The method according to any one of claims 6 to 12, wherein the thermal decomposition treatment is carried out at a thermal decomposition temperature in the range of 120°C to 900°C.

14. The resulting particulate water-insoluble inorganic material, comprising silver oxide and ruthenium oxide, is further treated by contacting it with at least one C1-C4 alkoxide of aluminum, magnesium, calcium, silicon, zinc, zirconium, and / or titanium in the presence of at least a sufficient amount of water for complete hydrolysis of the at least one C1-C4 alkoxide, thereby obtaining a lightness L in the range of 50-85. ＊ The method according to any one of claims 6 to 13, for forming a whitened particulate material having

15. Use of particulate water-insoluble inorganic material comprising silver oxide and ruthenium oxide as described in any one of claims 1 to 6, as an additive for antimicrobial treatment of metal surfaces, coatings such as varnishes and other paints, plaster, molding compounds, plastic films, plastic parts or plastic fibers, textiles or textile utility products, synthetic resin products, ion exchange resins, silicone products, cellulosic products, foams, and cosmetics, or as a heterogeneous catalyst in catalytic action for the formation of hydroxyl radicals in an aqueous medium that enables bacterial growth, or use of a product manufactured according to the method described in any one of claims 7 to 14.

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