EP2726204A2

EP2726204A2 - Production of a catalytically active, metalized reactive foam material and use thereof

Info

Publication number: EP2726204A2
Application number: EP12729903.0A
Authority: EP
Inventors: Wolfgang Kollmann
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-05-31
Filing date: 2012-05-25
Publication date: 2014-05-07
Also published as: JP6223327B2; HK1195027A1; US20140179513A1; WO2012163853A2; US9346041B2; CN105749989A; WO2012163853A3; CN103635259A; HK1227353A1; JP2017127873A; DE102011050758A1; JP2014523335A; CN103635259B

Abstract

The invention relates to a catalytic material which is used as an optofluidic reactor, and also a method for production thereof. In this case, first a reticulated plastic foam can be fabricated which then is coated with at least one first metal or metal alloy layer. Subsequently, a photocatalytic substrate is then applied to the metal or metal alloy layer. The photocatalytic substrate eliminates bacteria, viruses and other harmful substances, as well as fine dust or fungal spores, when the optofluidic reactor is used.

Description

OPTOFLUIDIK-RE ACTOR

The invention relates to an optofluidic reactor and thus a catalytic material for the elimination of bacteria, viruses or particulate matter and fungal spores and other pollutants.

In the prior art, it is known to use photocatalytic substrates as opto-fluidic reactors. Such a substrate is, for example, titanium dioxide (TiO ₂ ) - preferably in the tetragonal, crystalline form of anatase. The latter releases electrons when exposed to sunlight, breaking up contaminants or other pollutants into harmless substances. The release of electrons from the oxide and the associated photocatalytic reaction is composed of a series of physical and chemical processes. Essentially, oxygen radicals are formed on the surface of the oxide by the free electrons, which are also referred to as active oxygen. These oxygen radicals include free radicals, such as the hyperoxide anion, the hydroxyl radical, the peroxyl radical or alkoxyl radical, and also stable molecular radicals, such as the known oxygen peroxide, hydroperoxide, ozone, or the hypochlorite anion. These oxygen radicals decompose molecules and organic contaminants when they come in contact with the surface of the oxide. The activated oxygen also builds odors and air pollutants, such. As nitrogen oxides, and organic particulate matter effectively. Furthermore, this oxygen kills bacteria and viruses - even aggressive pathogens such as SARS and H5N1 are effectively combated on contact with the oxide surface.

The object of the present invention is in particular to provide an Optofluidrik reactor, which shows a high efficiency.

This task will

a) solved by the production of a catalytic material in which the photocatalysis and a fluid flow are combined.

b) On the other hand, this object is achieved by the provision of a coating in which a metal matrix with a catalytically active metal or metal oxide is formed on a surface. These two aspects can be advantageously combined with each other.

To a) For the purpose of fluid flow, a reticulated plastic foam of, for example, polyethersulfone (PES) or polypropylene (PP) or polyethylene (PE) or polyurethane (PU) or polyester or polyether is provided, which is reticulated as a base foam.

During reticulation, the thin intermediate walls between the individual foam cells are partially broken in such a way that the foam becomes fluid-permeable. Such a foam has an enormously large surface, which is contacted by the latter as it flows through a fluid. The fluid may be air to be purified or water to be purified. In this respect, the optofluidic reactor is preferably used for room air or water treatment. For water treatment, the optofluidic reactor can be embedded for its protection between UV-transparent layers, such as glass. This is then used in the flow gradient of a watercourse to be cleaned. A prefilter for filtering coarse suspended matter may be upstream.

Such a reticulated foam suitable for the fluid flow advantageously has a pore number of up to 34 ppi (pores per inch). As an example, the average number of pores is 9 ppi (fluctuation range of 8 to 10 ppi) or 10.5 ppi on average (fluctuation range of 8 to 13 ppi) or 14.5 ppi on average (fluctuation range of 12 to 17 ppi). or on average 19.5 ppi (range of variation from 16 to 23 ppi) or on average 25.5 (range of variation from 12 to 29 ppi) or on average 30.5 (range of variation from 27 to 34 ppi).

The reticulated base foam is then coated in a further process step with at least one first metal or metal alloy layer. As a result, the foam undergoes solidification, so that the resulting solid composite z. B. in sheet form as a ceiling element in rooms or as partitions can be used herein. This metal coating also embrittlement of the base material, ie the foam is prevented by light. Furthermore, such a coated foam by the appropriate choice of a metal or a metal alloy fulfills decorative claims. The layer thickness of the metal is chosen so that the coated foam material acquires an Eigentragfähigkeit. Also, this can cause sagging or sagging of the Composite material in that it is designed as a plate can be prevented. By choosing the layer thickness of the metal, the material is well controllable in terms of its strength. Also, several metal layers can be applied one after the other. A suitable layer thickness has at least one (number word) micrometer. While metal foaming by thin foaming ensures good results for thin foam boards, wet-chemical coating processes are advantageous for thicker foam boards because they allow the thicker foam to be well coated down to its center.

As coating metals, all physically, thermally or wet-chemically depositable metals or metal alloys are suitable.

The metallically coated foam composite material is now an ideal support for the catalytically active layer to be subsequently applied, ie the photocatalytic substrate. Titanium dioxide (TiO ₂ ) - preferably in the tetragonal, crystalline form of anatase - or a metal layer of copper, nickel, zinc, tin, cobalt or manganese, or alloys or oxides, also in mixtures of the individual oxides, is used as a suitable photocatalytic substrate , from this. Also suitable as the photocatalytic substrate is a noble metal layer of silver, palladium or platinum or of alloys and compositions thereof.

Then, an optofluidic reactor is provided which, thanks to its strength, can be easily cleaned with water or the like by the at least one first metal layer without losing its effect. The above combination according to the invention of photocatalysis and fluid flow show a tremendous improvement in the efficiency of the photocatalyst. The channels produced in the foam, which branch out like branches in the foam, provide a high surface area to fluid volume ratio, thus achieving better purification of the optofluidic reactor of the present invention.

A preferred exemplary embodiment is described below: A reticulated plastic foam having a preferred pore number of 12-17 ppi and a thickness of 10 mm is coated in a first coating step with a copper layer which is a few nanometers to one (1 μm) or several micrometers thick. which is applied by vapor deposition, sputtering or by electroplating on the foam. This first metal layer is then reinforced by a further layer by means of metallization by galvanic means with copper, iron or aluminum with a layer thickness of more than 20 μιη. As corrosion protection, a nickel, white bronze or cobalt-tin layer which can be combined with an anti-allergenic cobalt-tin metal layer is applied galvanically to this copper layer. Instead of this layer or layer combination can also be a noble metal layer of z. As palladium, platinum or silver or alloys thereof - including as an alloy with one of the above metals nickel, zinc, white bronze, cobalt or tin. Layer thicknesses of at least 5 μm were found to be advantageous. The metallized material obtained by the coating is subsequently coated with a titanium dioxide layer as a photocatalytic substrate by dipping or flooding the foam or spraying it on. The coating is a sol or gel-based water or solvent based titanium dioxide solution. In addition to its photocatalytic action, this coating is also superhydrophilic, self-cleaning and highly antimicrobial.

From a molded body, which is obtained from a material according to the above description, interior ceiling panels or room divider can be made, which clean the room air. Also, design elements are advantageous, which can be set up indoors to clean the room air. In this case, the most varied forms of the material can be formed. In such embodiments, in addition to the air cleaning effect and the sound attenuation is remarkable. Thus, the interior elements can be useful also used in open-plan offices for noise reduction.

For the purpose of shaping, the individual opto-fluidics elements, for example plates, can be connected to one another, for example adhesively bonded. It should be ensured that sufficient UV light can penetrate into the center of the elements connected in this way and a flow is ensured.

A reactor made of elements between which a UV lamp is embedded proves to be advantageous. This radiates from the center of the reactor UV light to the outside. In addition to the emitted UV light, the integrated lamp can also emit light in the visible range, so that such a reactor then also serves as a luminaire. Such a connected lamp also leads by the resulting convection of the lamp by the resulting heat for forced flow through the Optofluidik reactor.

Also according to the invention comprises a ventilation device that has as an essential functional element an opto-fluidic reactor, as described above. Such a ventilation device has a fan or the like to forcibly flow through the optofluidic reactor with air. This forced flow of the photocatalytic reactor increases the cleaning effect of the air many times. Advantageously, the foam material according to the invention can be easily replaced as optofluidic reactor in such a ventilation device, d. H. dismantle, and also clean.

Advantageously, the optofluidic reactor according to the invention can also be used as a filter body for air suction hoods. These are in the art for kitchens, or for sucking vapors z. As solvents, welding fumes, or flue gases used.

The photocatalytic effect of the optofluidic reactor can be advantageously increased as already shown above, when it is irradiated with a UV-A lamp. In this respect, an advantageous embodiment of the ventilation device, the extractor hood or the interior molded body on such a UV-A lamp, with which then the optofluidic reactor can be irradiated if necessary. In this respect, it is also suitable to form a design body from the metallized foam material according to the invention, which is irradiated with such a UV lamp. The attached Figures 1 and 2 are photographs of a reticulated base foam, as it can be used as starting material for the Optofluidik reactor. FIG. 2 is an enlarged view of the foam of FIG. 1. FIG.

With reference to the solution variant b), according to which a metal matrix is formed on a surface, a new coating for the purpose of decontamination of bacteria, viruses and other general impurities is shown below. In addition to a coating for a reticulated base foam, as described above and explained for a variety of applications, there are also additional coating applications without fluid flooding, such as for door handles, sanitary fittings, or for all surfaces that touch experienced and thus exposed to contamination with bacteria and viruses. This concerns applications in the home, hospitals or public institutions.

It is known to disperse in galvanic electrolytes different substances, such as diamond dust, SiC, Al ₂ O ₃ , CBN, WC, TiC, PTFE or graphite and galvanically with the respective electrolyte (eg sulfamate nickel, Watf s sulfate nickel or similar). or electrolessly (eg, chemically nickel) on a respective component to be deposited in order to reduce abrasion, to increase temperature resistance or to improve sliding properties. According to the present invention is TiO ₂ - preferably in the anatase form - adapted for use as a photocatalytically active dispersion layer as so-called TiO2-metal matrix layer.. The preferred particle size of the Ti0 ₂ is 0-3μιη; eg KRONOClean 7000 and KRONOClean 7050 It is also possible to use nanoscale TiO ₂ particles with a size of about 20 nm, whereby the preparation of the suspension may be complicated due to conglomeration problems, but is feasible. For nanoscale particles, it helps to use dispersant chemicals.

The basic procedure for the coating with eg TiO ₂ - ENiP (TiO ₂ with chemical nickel-phosphorus metal layer) or Galvanic NiP is described below for the reticulated foam for air and water purification as well as for plastic components:

1. The reticulated foam is coated in a first coating step with preferably a copper layer> 1 μιη by vapor deposition or by electroless process (chemical copper). 2. This first metal layer is galvanically coated with copper, iron, or aluminum (preferably Cu) with a layer thickness of more than 10 μιη until the foam acquires its own rigidity.

3. On this layer, another metal or metal alloy layer z. B. Ni, white bronze, yellow bronze, NiP, Cr, NiKo, ENiCoP, applied with a layer thickness> 5 μιη. 4. The photocatalytic, for example, NiP-Ti0 ₂ layer with a layer thickness> 1 μm is applied to this layer

It is also possible to apply a Cu-Ti0 ₂ layer with a layer thickness> Ιμιη on the first metal layer produced according to point 2.

According to one embodiment, it is possible to apply the photocatalytic layer directly to the copper layer 2 without further intermediate layer

According to one embodiment, it is also possible to apply a layer to the photocatalytic layer 4, e.g. Bright chrome, or a noble metal e.g. Au, Pd, Rt or Pt.

For metallic workpieces step 1 is omitted

Exemplary embodiment for producing an electrolyte for forming a metal matrix with a T102-Ni deposition after step 4:

Watf shear (sulfate) nickel electrolyte with the composition

NiSO4.6H20 350 g / 1

NiC12.6H20 45 g / l

H3B03 45g / 1

pH 4

T 55 ° C

TiO 2 20-150 g / 1 particle size 0-3 μιη

Cathodic current density 5 A / dm2

Cationic Fluorosurfactant 0.2 g / 1 FT 248 (BASF) With this composition, a rate of incorporation of up to 50% by weight is possible. According to one embodiment, it is also possible to use a wetting agent such as sodium dodecyl sulfate or standard wetting agents from galvanic chemicals supply companies to prevent pore formation.

The Ti0 ₂ particles are held in suspension by an electrolyte movement by means of mechanical stirring. A gentle air injection is advantageous.

The respective exact Ti0 ₂ concentration depends on the desired incorporation rate of the oxide and the component geometry, as well as in general of the component (surface roughness, microgeometry, etc.).

The rate of stirring and the applied current density as a function of the component geometry and the stated microstructure also have a significant influence on the incorporation rate.

It is also essential to strictly adhere to the pH, since residues of, for example, precursor substances can adhere to the TiO ₂ particles to be stored (alkaline and acidic). The TiO ₂ - metal matrix deposition is possible with a wide variety of electrolytes as matrix metal. The matrix metals used as electroplated (by current) which are used are NiP, Ni, Co, Cu, W, Mn, Mo, Cr, Sn, Zn, (hard chromium), noble metals such as Pd, Pt, ruthenium, rhodium, and the like Alloys suitable. Also, sulfamate electrolytes or ionic liquids can be used.

Also, the matrix metal is used with electroless processes such as chemical nickel-phosphorus and a variety of alloys, e.g. Ni-Co-P (hydrazine reducing agent), Co-P, Ni-Cu-P, Ni-W-P, Ni-Mo-P, and chemically copper.

The big advantage of these Ti0 ₂ - intercalation layers is that the catalytically active particles are fixed firmly in a very abrasion-resistant metal matrix and consequently a very long duration of action is to be expected.

In addition, new TiO ₂ particles are always exposed on the surface at any time, even with incoming wear of the coating, and thus continue to work until complete wear of the coating occurs. In contrast to coatings applied in the sol-gel process, painting process (wet, powder coating), or thin-film processes (sputtering, vapor deposition, etc.), these coatings of a metal matrix last incomparably longer and thus make them predestined for abrasion-stressed components and surfaces which are often damaged by, for example, , B. be claimed and contaminated, for example, especially in hospitals with different bacteria and viruses. Ti0 ₂ metal matrix layers produced in this way have the great advantage that in combination with light, they continuously reduce viruses and bacteria in door clinics, gripping surfaces, etc., and thus ensure maximum safety against contagion and transmission of diseases through contact contamination outside of cleaning cycles ,

The entry of Ti0 ₂ - particles in the environment is thus minimized compared to less abrasion resistant paint layers.

With the described method, it is also possible to coat metallized, textile base materials such as nonwovens, fabrics and the like of plastic, glass, or carbon base material.

Claims

Λ Α. Claims:

1. A process for the preparation of a catalytic material for the elimination of pollutants, comprising

- The production of a reticulated plastic foam as a plate with a thickness of at least 10 mm;

- Applying at least one first metal or metal alloy layer on the surface of the reticulated foam sheet;

- Applying a photocatalytic substrate on the metal or metal alloy layer as a solution prepared by sol-gel method by dipping or flooding on the metal or metal alloy layer.

2. The method according to claim 1,

characterized in that the photocatalytic substrate

Titanium Dioxide TiO ₂ is or

a metal layer of copper, nickel, zinc, tin, cobalt or manganese, or of alloys or oxides thereof,

or a noble metal layer of silver, palladium, platinum or alloys thereof

or an alloy of at least two metals of the group copper, nickel, zinc, tin, cobalt, manganese, silver, palladium, platinum.

3. The method according to any one of the preceding claims,

characterized in that following the at least one first metal layer and before the application of the photocatalytic substrate, a further metal layer

- Copper, aluminum, nickel, tin, zinc, silver, palladium, platinum or alloys thereof is applied therefrom.

4. The method according to any one of the preceding claims,

characterized in that the reticulated foam is of polyethersulfone (PES) or polypropylene (PP) or polyethylene (PE) or polyurethane (PU) or polyester or polyether.

5. The method according to any one of the preceding claims,

characterized in that the reticulated foam has a pore number up to 34 ppi (pores per inch).

6. A process for the preparation of a catalytic material or a coating for the elimination of pollutants, in which process a photocatalytically active dispersion layer is formed as a metal-matrix layer on a surface.

7. Interior element of a manufacturing method of an optofluidic catalyst material according to one of claims 1 to 6.

8. Ventilation device with an element from a production process of an optofluidic catalyst material according to one of claims 1 to 6.

9. Ventilation device according to claim 8,

characterized in that the ventilation device comprises a UV lamp.

10. Ventilation device according to claim 8 or 9,

characterized in that the element of optofluidic catalyst material is designed as a filter insert of the ventilation device.