Device for cleaning a medium

Abstract

A device (10) for cleaning a medium (105) comprises a porous body (100), which contains a photocatalytic material (102), and a waveguide (110), which is designed to conduct electromagnetic radiation into the interior of the porous body (100).

Description

[0001] DEVICE FOR CLEANING A MEDIUM

[0002] DESCRIPTION

[0003] In general, we are looking for concepts that can be used to purify media, such as gases (air) or liquids (water). In particular, we are looking for concepts that enable more efficient purification of media.

[0004] The present invention is based on the object of providing an improved device for cleaning a medium.

[0005] According to embodiments, the problem is solved by the subject matter of the independent patent claims. Further developments are defined in the dependent patent claims.

[0006] A device for cleaning a medium comprises a porous body containing a photocatalytic material and a waveguide configured to guide electromagnetic radiation into the interior of the porous body.

[0007] According to embodiments, a radial transmittance of the waveguide for electromagnetic radiation increases with increasing distance from a coupling position of the electromagnetic radiation.

[0008] For example, the waveguide is cylindrical and coated with a reflective material.

[0009] According to embodiments, a layer thickness of the reflective material can decrease with increasing distance from the coupling position of the electromagnetic radiation. According to further embodiments, the reflective material can be applied with a variable coating density. Furthermore, the coating density can decrease with increasing distance from the coupling position of the electromagnetic radiation.

[0010] According to further embodiments, the waveguide can taper with increasing distance from the coupling position of electromagnetic radiation.

[0011] For example, the waveguide can be coated with a reflective material. The thickness of the reflective material can decrease with increasing distance from the coupling point of the electromagnetic radiation.

[0012] According to embodiments, a surface of the waveguide at a coupling position of the electromagnetic radiation may protrude from the porous body and be curved.

[0013] For example, the porous body can be designed as an aerogel.

[0014] According to embodiments, the photocatalytic material contains TiO2. For example, titanium dioxide can be used in the anatase form. According to further embodiments, titanium dioxide can be used in the rutile crystal structure. Alternatively or additionally, the photocatalytic material can comprise or consist of the following materials as photocatalyst: semiconductor materials based on dO transition metal cations such as Ta5+ or Nb5+, nitrides or oxides of Ga. 3+ , In 3+ or Bi 3+, metal-organic frameworks (MOEs), such as MOF-5, UiO-66, or UiO-66 (NH2). The device may further comprise a light source for emitting the electromagnetic radiation.

[0015] According to embodiments, the device comprises a first boundary surface and a second boundary surface opposite the first boundary surface, as well as a plurality of waveguides. The porous body is arranged between the first and second boundary surfaces. A portion of the waveguides extends from the first boundary surface, and another portion of the waveguides extends from the second boundary surface into the interior of the device.

[0016] The accompanying drawings are intended to provide an understanding of embodiments of the invention. The drawings illustrate embodiments and, together with the description, serve to explain the same. Further embodiments and many of the intended advantages will be readily apparent from the following detailed description. The elements and structures shown in the drawings are not necessarily to scale. Like reference numerals refer to like or corresponding elements and structures.

[0017] Fig. 1A shows a schematic cross-sectional view of a device for cleaning a medium.

[0018] Fig. 1B shows a schematic cross-sectional view through a porous body.

[0019] Fig. IC shows a schematic structure of a waveguide.

[0020] Fig. 1D shows a schematic cross-sectional view through a part of the device according to embodiments. Fig. 2A shows a schematic cross-sectional view of a waveguide according to further examples.

[0021] Fig. 2B illustrates a transmittance of layers .

[0022] Fig. 3A shows a cross-sectional view of a waveguide according to further examples.

[0023] Fig. 3B shows a radial cross-sectional view through a reflective material.

[0024] Fig. 4 shows a cross-sectional view through the device according to further embodiments.

[0025] In the following detailed description, reference is made to the accompanying drawings, which form a part of the disclosure, and in which specific embodiments are shown for purposes of illustration. In this context, directional terminology such as "top," "bottom," "front," "back," "over," "on," "in front of," "behind," "fore," "rear," etc., refers to the orientation of the figures just described. Since the components of the embodiments can be positioned in different orientations, the directional terminology is for the purpose of explanation only and is in no way limiting.

[0026] The description of the embodiments is not limiting, as other embodiments exist and structural or logical changes may be made without departing from the scope defined by the claims. In particular, elements of embodiments described below may be combined with elements of other described embodiments, unless the context indicates otherwise.

[0027] Fig. 1A shows a cross-sectional view of a device 10 for cleaning a medium 105 according to embodiments. The device 10 has a porous body 100. The porous body 100 contains a photocatalytic material 102 (not shown in Fig. 1A). For example, the porous body 100 can be constructed from photocatalytic material 102. According to further embodiments, the porous body 100 can also be constructed from a suitable material and coated with the photocatalytic material 102. The device 10 further has a waveguide 110 which is configured to guide electromagnetic radiation 15 into the interior of the porous body 100.

[0028] As shown in Fig. 1A, for example, a medium 105 to be cleaned, for example a liquid (e.g. water) or a gas to be cleaned (e.g. air), can flow into the porous body 100 from the left side, for example via an inlet 116. The medium 105 can leave the body as a cleaned medium 107, for example via the outlet 117. A flow direction 108, for example a direction between the inlet 116 and the outlet 117, can run along an x-axis, for example. The device 10 for cleaning a medium can have a plurality of waveguides 110. The waveguide(s) 110 penetrate, for example, the porous body 100 in a vertical direction, for example in a direction perpendicular to the flow direction 108. In general, the waveguides 110 may extend in any direction that intersects the flow direction 108.For example, an extension direction of the waveguide 110 can define a vertical direction. A radial or horizontal plane runs perpendicular to the vertical direction. For example, a part of the waveguides 110 can extend from a first main surface 113 of the device 10. Another part of the waveguides 110 can extend from a second main surface 114 of the device 10. The second main surface 114 can be opposite the first main surface 113. According to further embodiments, further waveguides 110 can extend from further boundary surfaces of the device 10. According to further embodiments, the device 10 can also be cylindrical, and the waveguides are arranged along the cylindrical boundary surface of the device 10. In this way, more uniform illumination can be ensured.

[0029] For example, the waveguides 110 can each be arranged such that waveguides 110 extending from a specific boundary surface of the device 10 are illuminated from this side with electromagnetic radiation 15. Furthermore, waveguides 110 extending from the side of the first main surface 113 can alternate with waveguides extending from an opposite boundary surface. The individual waveguides 110 can be arranged at the same or different distance d from one another. For example, the distance d can be determined as a function of a penetration depth of the electromagnetic radiation 15 into the porous body 100.

[0030] According to further embodiments, the device 10 for cleaning a medium 105 can additionally comprise a light source 20 for emitting electromagnetic radiation. According to further embodiments, however, the light source 20 can also be an external component. The light source 20 can be configured to emit electromagnetic radiation 15 at a wavelength by which the photocatalytic material 102 can be excited. More precise examples of suitable wavelengths are given below.

[0031] The described configuration of the waveguide 110 can prevent introduced radiation 15 from being absorbed in the uppermost regions of the porous body 100. In particular, it can thus be achieved that a portion of the introduced radiation 15 reaches regions inside the porous body 100. As a result, a more homogeneous cleaning can be achieved in the region of the device 10 or the porous body 100.

[0032] Fig. 1B shows in the lower part a schematic perspective view of the porous body 100. The porous body 100 can be constructed from individual structural elements 101, which can be spherical or rounded, for example. Intermediate spaces can be provided between the individual structural elements. In this way, the medium to be cleaned can flow through the porous body 100. The individual structural elements 101 or the porous body 100 can be constructed from a photocatalytic material. According to further embodiments, the individual structural elements 101 or the porous body 100 can also be constructed from a suitable carrier material and coated with a photocatalytic material 102. For example, nanoparticles made of the photocatalytic material 102 can be applied to the surface of the porous body 100 or the individual structural elements 101.

[0033] In the context of the present description, the term "photocatalytic material" refers to a material that is suitable for causing a catalytic reaction when exposed to electromagnetic radiation of a suitable wavelength. For example, the photocatalytic material can be excited by the electromagnetic radiation. For example, the photocatalytic material can comprise a semiconductor material, for example TiC. Incident electromagnetic radiation can generate electron-hole pairs if the energy of the incoming photons is greater than the band gap E gThe electrons or holes can diffuse to the surface of the semiconductor material and generate radicals there, which lead to the decomposition of organic substances. For example, the holes in particular can have a strong oxidative effect. For example, OH radicals can be formed from water. This can decompose organic substances. Possible end products include CO2 and water.

[0034] The band gap of anatase, the form of TiO2 most efficient for photocatalysis, is 3.2 eV. This corresponds to a wavelength of electromagnetic radiation of approximately 390 nm. For example, ultraviolet light, which can generate electron-hole pairs in the corresponding semiconductor material, can be used for photocatalysis. For example, the light source 20 can be configured to emit UV radiation or electromagnetic radiation with a wavelength of 390 nm or less. As further shown in Fig. 1B, the photocatalytic material can be constructed as an aerogel. More precisely, the photocatalytically active material can be brought into a highly porous form, for example by a sol-gel process.

[0035] Fig. 1C shows a cross-sectional view of the waveguide 110. The waveguide 110 can, for example, comprise a suitable waveguide material, for example SiO2 or another suitable material. For example, the waveguide 110 can consist of or contain quartz glass. Other suitable materials can be, for example, sapphire (Al2O3), aluminum nitride (AlN), magnesium fluoride (MgF2) or calcium fluoride (CaF2). Furthermore, the waveguide 110 can be cylindrical. For example, a diameter of the cylinder can be constant along the z-direction. A reflective material 111 can be applied to the surface of the cylinder or the waveguide 110.

[0036] According to embodiments, a radial transmittance of the waveguide 110 may increase with increasing distance from a coupling position 109 of electromagnetic radiation.

[0037] Fig. 1D shows an example of a cross-sectional view through the porous body 100 and the waveguides 110 along the direction I-I', as indicated in Fig. 1A. The cross-sectional view of Fig. 1D can be taken in an xy plane, i.e. a horizontal plane. For example, the individual waveguides 110 can be arranged in rows, wherein the electromagnetic radiation 15 is radiated into the rows of waveguides 110 from one direction. Electromagnetic radiation 15 is also radiated into adjacent rows from different sides. For example, the individual waveguides 110 can be arranged in a checkerboard pattern. According to further embodiments, however, other arrangement possibilities are also conceivable. Furthermore, the cross-section of the waveguides 110 can be round or have any other shape.

[0038] Fig. 2A shows a cross-sectional view of a waveguide 110 along the vertical or z-direction according to embodiments. For example, a waveguide 110 can be coated with a reflective material 111 which has a sufficient penetration depth for the irradiated electromagnetic radiation 15. Accordingly, the proportion of the incident radiation can be controlled by varying the layer thickness of the reflective material 111. The layer thickness d, which is measured, for example, in the radial or horizontal direction perpendicular to the z-direction, varies. It is greater adjacent to a coupling position 109, where the electromagnetic radiation 15 is irradiated, and decreases towards the end of the waveguide. As a result, the proportion of light coupled out in the radial direction increases with increasing distance from the coupling position 109.As a result, the decreasing intensity in the porous body due to absorption in the areas near the coupling position 109 can be compensated.

[0039] In the right part of Fig. 2A the reflectivity is shown as a function of the distance from the coupling position of the electromagnetic radiation 15.

[0040] For example, suitable fluorine-containing polymer films can be used as material III. A specific example includes CTFE / VDF (chlorotrifluoroethylene / vinylidene fluoride).

[0041] Fig. 2B shows, as an example, the transmittance of a CTFE / VDF polymer film with different layer thicknesses as a function of wavelength. As can be seen, the smaller the layer thickness, the greater the transmittance.

[0042] Fig. 3A shows a cross-sectional view of a waveguide 110 along the z-direction according to further embodiments. For example, the waveguide 110 can be partially covered on its surface with a highly reflective material, resulting in individual material islands 112. Examples of a highly reflective material include, for example, aluminum. Furthermore, the coverage density with the material islands 112 can decrease with increasing distance from a coupling position 109 into the waveguide. This is illustrated schematically in Fig. 3A. The right-hand part of Fig. 3A again shows the reflectivity as a function of the distance from a coupling surface of the electromagnetic radiation 15.For example, the highly reflective material can be applied using a physical vapor deposition process (PVD) or a chemical vapor deposition process (CVD). In particular, a physical vapor deposition process can ensure a high level of control over the layer thicknesses and produce layers of high optical quality.

[0043] Fig. 3B shows cross-sectional views through the reflective material 111 at different distances from a coupling position 109 of the electromagnetic radiation. The lower part of Fig. 3B is taken between I and 1', i.e. close to a coupling position 109 for electromagnetic radiation 15. As can be seen, the coverage density with the material islands 112 is comparatively high. The upper part of Fig. 3B shows a cross-sectional view between II and II' with a greater distance from the coupling position 109. Here, the density of the material islands 112 is comparatively low.

[0044] Fig. 4 shows a cross-sectional view through the device 10 according to further embodiments. As shown, according to further embodiments, the waveguide 110 can be formed in a shape that is not cylindrical. For example, the waveguide 110 can taper with increasing distance from the coupling position 109 of electromagnetic radiation. As a result, a corresponding curvature along the z-axis of the waveguide 110 can occur. For example, the waveguide 110 can taper conically with increasing distance from the coupling position 109. This shape of the waveguide ("cone") serves as a converging lens for the light to be coupled in and increases the "coupling cross-section" into the waveguide.

[0045] The downward taper of the waveguide 110 ensures that the surface normal tends to be rotated in the direction of the scattered light and thus the coupling efficiency increases downwards - purely due to the geometry of the waveguide.

[0046] As a result, the introduced radiation 15 can be prevented from being absorbed in the uppermost regions of the porous body 100. More specifically, a portion of the introduced radiation 15 can thus reach regions inside the porous body 100. As a result, a more homogeneous cleaning can be achieved in the region of the device 10 or the porous body 100.

[0047] In the structure shown in Fig. 4, for example, a surface 115 of the waveguide can be curved and thus act as a lens, thereby increasing the collection effect.

[0048] Additionally, a variable transmittance in the radial direction can be provided by a suitable coating. For example, a gradual coating can be additionally provided on a surface of the region of the waveguide 110 that extends through the porous body 100. For example, this can again comprise a reflective layer 111 that has a sufficient penetration depth for electromagnetic radiation.

[0049] Although specific embodiments have been illustrated and described herein, those skilled in the art will recognize that numerous alternative and / or equivalent embodiments may be substituted for the specific embodiments shown and described without departing from the scope of the invention. This application is intended to cover any adaptations or variations of the specific embodiments discussed herein. Therefore, the invention is limited only by the claims and their equivalents.

[0050] LIST OF REFERENCE SYMBOLS

[0051] Device for cleaning a medium electromagnetic radiation light source porous body structural element photocatalytic material medium to be cleaned cleaned medium flow direction coupling position waveguide reflective material material island first main surface second main surface surface of the waveguide inlet outlet

Claims

CLAIMS 1. Device (10) for cleaning a medium (105), comprising: a porous body (100) containing a photocatalytic material (102), and a waveguide (110) configured to guide electromagnetic radiation into the interior of the porous body (100), wherein the waveguide (110) runs along a direction that intersects a flow direction (108) of the medium (105) through the porous body (100).

2. Device (10) according to claim 1, wherein a radial transmittance of the waveguide (100) for electromagnetic radiation (15) increases with increasing distance from a coupling position (109) of the electromagnetic radiation (15).

3. Device (10) according to claim 1 or 2, wherein the waveguide (110) is cylindrical and coated with a reflective material (111).

4. Device (10) according to claim 3, wherein a layer thickness of the reflective material (111) decreases with increasing distance from the coupling position (109) of the electromagnetic radiation (15).

5. Device (10) according to claim 3, wherein the reflective material (111) is applied with a variable coverage density, and the coverage density decreases with increasing distance from the coupling position (109) of the electromagnetic radiation (15).

6. Device (10) according to claim 1 or 2, wherein the waveguide (110) tapers with increasing distance from the coupling position (109) of electromagnetic radiation (15).

7. Device (10) according to claim 6, wherein the waveguide (110) is coated with a reflective material (111) whose layer thickness decreases with increasing distance from the coupling position (109) of the electromagnetic radiation (15).

8. Device (10) according to one of the preceding claims, wherein a surface (115) of the waveguide (110) protrudes and is curved relative to the porous body (100) at a coupling position (109) of the electromagnetic radiation (15).

9. Device (10) according to one of the preceding claims, wherein the porous body (100) is designed as an aerogel.

10. Device (10) according to one of the preceding claims, wherein the photocatalytic material (102) is selected to contain TiO2.

11. Device (10) according to one of the preceding claims, further comprising a light source (20) for emitting the electromagnetic radiation (15).

12. Device (10) according to one of the preceding claims, with a first boundary surface (113) and a second boundary surface (114) which is opposite the first boundary surface (113), and a plurality of waveguides (110), wherein the porous body (100) is arranged between the first and the second boundary surface (113, 114) is arranged and a part of the waveguides (110) extends from the first boundary surface (113) and another part of the waveguides (110) extends from the second boundary surface (114) into the interior of the device (10).

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