WO2014008953A1 - Matière à action photocatalytique pour purifier l'air - Google Patents

Matière à action photocatalytique pour purifier l'air Download PDF

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Publication number
WO2014008953A1
WO2014008953A1 PCT/EP2012/065968 EP2012065968W WO2014008953A1 WO 2014008953 A1 WO2014008953 A1 WO 2014008953A1 EP 2012065968 W EP2012065968 W EP 2012065968W WO 2014008953 A1 WO2014008953 A1 WO 2014008953A1
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WO
WIPO (PCT)
Prior art keywords
photocatalyst
light
photocatalytic material
fine dust
particulate matter
Prior art date
Application number
PCT/EP2012/065968
Other languages
German (de)
English (en)
Inventor
Thomas RETTENMOSER
Original Assignee
Anlarop Development Ag
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Anlarop Development Ag filed Critical Anlarop Development Ag
Publication of WO2014008953A1 publication Critical patent/WO2014008953A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D49/00—Separating dispersed particles from gases, air or vapours by other methods
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/207—Transition metals
    • B01D2255/20792—Zinc
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/20—Metals or compounds thereof
    • B01D2255/209—Other metals
    • B01D2255/2094—Tin
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2255/00—Catalysts
    • B01D2255/80—Type of catalytic reaction
    • B01D2255/804—Enzymatic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D2259/00—Type of treatment
    • B01D2259/45—Gas separation or purification devices adapted for specific applications
    • B01D2259/4508—Gas separation or purification devices adapted for specific applications for cleaning air in buildings

Definitions

  • the invention relates to a method for reducing particulate matter using a photocatalyst and a photocatalyst, which is active even in the absence of UV light
  • Photocatalysts are excited in a photoassisted catalytic reaction. This is used, for example, to generate oxygen radicals on the surface of photocatalysts, which in turn can then oxidize pollutants and thus make them harmless.
  • a well-known photocatalytically active material is titanium dioxide (Ti0 2 ). To excite titanium dioxide UV light is necessary.
  • An object of the present invention was to utilize photocatalytic effects for new applications and also to provide new photocatalysts which are photocatalytically active even in the absence of UV light.
  • This object is achieved by a method for reducing particulate matter, which is characterized in that particulate matter is separated from a gaseous medium by means of a photocatalytic material.
  • the invention relates to a method for fine dust reduction, which is characterized in that fine dust is separated from a gaseous medium by means of a photocatalytic material in daylight.
  • the invention relates to a method for reducing particulate matter, which is characterized in that particulate matter from a gaseous medium is separated by means of a photocatalytic material without UV light.
  • the photocatalytic material is caused by the action of light of a suitable wavelength in an excited state catalyst. It is to maintain the reaction, a continued exposure to light required.
  • Photocatalytic material is also referred to herein as a photocatalytically active material.
  • the photocatalytic materials which can be used according to the invention preferably comprise a photocatalyst and optionally further materials such as, for example, binders.
  • the photocatalyst which may also be referred to as a photocatalytically active substance, preferably has semiconductor properties.
  • a photocatalytically active semiconductor electrons can be put into an energetically higher state by excitation by light photons. If the energy of the incoming photon is sufficiently large, then an electron can change from an energetic state, for example from an energetic ground state, to the energetic state of the conduction band at room temperature. At the original part of the electron (negative charge carrier), a defect electron or hole is created, ie a positive charge carrier. At this point, an adjacent electron can change.
  • the photocatalyst is a material which is also active when exposed to visible light, ie in particular also in the absence of UV light, the charge distributions are also formed without irradiation of UV light.
  • Such materials can thus also be used for reducing particulate matter in the interior, for example in interior interiors or vehicle interiors, in which no photo-assisted catalytic reaction occurs when conventional photocatalysts such as titanium dioxide are used because of the absence of UV radiation
  • the inventive method can be carried out in daylight. In particular, it is carried out in daylight without additional UV light.
  • the method is attenuated in daylight with a weakened portion of UV light, more preferably at least 20%, more preferably at least 30%, even more preferably at least 50%, and most preferably at least 80%, most preferably at least 90% Proportion of light with wavelengths of ⁇ 350 nm, preferably ⁇ 380 nm and in particular ⁇ 390 nm performed.
  • An example of such a preferred embodiment is indoor implementation in which daylight first has to pass through glass, for example window glass, which has only a partial UV transmittance, in a preferred embodiment the process is in daylight without UV light components performed.
  • the method according to the invention can also be carried out under artificial light, in particular with artificial light having a wavelength of 380 nm to 800 nm, in particular from 400 to 700 nm.
  • the method according to the invention can also be carried out in environments in which no additional UV light is irradiated especially in environments where no UV light is present.
  • the method according to the invention can be carried out in particular even in the absence of light having a wavelength of ⁇ 400 nm, in particular ⁇ 380 nm, even more preferably ⁇ 350 nm.
  • the photocatalyst preferably comprises at least one of Sn, Zn, Bi, Ga, Ge, In, Ta, Ti, V, W, Sb or ⁇ , in particular at least one of Sn, Zn, Ta, Bi, In, V, W, Sb, Ge, Ga, TI or / and titanium, and even more preferably Sn or / and Zn.
  • the photocatalyst Sn comprises. In another preferred embodiment, the photocatalyst comprises Zn. In yet another preferred embodiment, the photocatalyst comprises Sn and Zn.
  • the elements are preferably in the form of compounds having semiconductor properties, for example as oxides.
  • the photocatalyst comprises tin oxide (SnO 2 ) or / and zinc oxide (ZnO).
  • Sn0 second Sn0 2 has an energy band gap of 3.5 to 3.7 eV corresponding to a wavelength range of 354 to 335 nm.
  • Charged SnO * has an energy band gap of about 2.9 eV corresponding to a wavelength of 428 nm.
  • Sn0 2 be excited by blue light in the electromagnetic spectrum of visible light.
  • a further preferred material used as the photocatalyst is ZnO.
  • 5 ZnO has an energy band gap of about 3.37 eV corresponding to a wavelength of 368 nm.
  • the photocatalyst used is a mixture of SnO 2 and ZnO, in particular in a weight ratio of from 1:10 to 10: 1, more preferably from 1: 3 to 3: 1.
  • the band gaps of the active particles used are preferably reduced
  • a photocatalyst which is doped with one or more elements, in particular selected from Co, C, N, P, S or H.
  • a photocatalyst is used which is doped with Co, C and / or N, most preferably with Co.
  • doping foreign atoms are incorporated into the molecular structure of the photocatalyst. The doping reduces the band gap and thus the activation energy.
  • ZnO or / and SnO 2 doped with Co 5, in particular Co doped ZnO is particularly preferably used as the photocatalyst.
  • the weight ratio Zn: Co is preferably from 8: 1 to 15: 1, in particular from 9: 1 to 11: 1 and even more preferably from 9.5: 1 to 10.5: 1. It has been found according to the invention that Co is incorporated into the crystal structure of ZnO.
  • Co-loaded ZnO has energy band gaps at about 1.8 eV and 2.7 eV, corresponding to a wavelength of 690 nm and 460, respectively nm. Due to the shift of the necessary activation energy in the visible wavelength range, these materials can be used as a photocatalyst even when irradiated with light without any UV component.
  • Doped photocatalysts can be obtained, for example, by wet-chemical or thermal processes.
  • the photocatalyst is provided with one or more elements, in particular selected from Pb, Au, Ag, Pt, Al, Cu, Sb, Mo or Cd, preferably selected from Au, Pt, Ag, Sb, Fe, Al, Cd, Cu or Pb loaded.
  • a loading of Au or / and Pt is given to loading with nanoparticles, in particular with nanoparticles, which have an average particle size of ⁇ 10 nm, in particular ⁇ 5 nm.
  • loading takes place with Au and / or R nanoparticles which have an average particle size -S 10 nm, in particular s 5 nm.
  • different particles and / or different particle sizes are mixed for the photocatalyst.
  • the mixture of ZnO and SnO 2 is preferred.
  • identical or different materials in different particle sizes are preferably used, for example in mixtures of particle sizes ⁇ 50 nm, in particle sizes of 50 to ⁇ 150 nm and in particle sizes of 150 to 300 nm. It has been found that the particle size also has an influence on the band gap , In particular, small particles are preferred. On the other hand offer larger particles more potential attachment surface for fine dust.
  • preference is given to using a mixture of different particle sizes
  • the photocatalytic material used according to the invention comprises
  • the photocatalyst is preferably used in the form of small particles.
  • the photocatalytic material has a particle size of ⁇ 1000 nm, more preferably 500 500 nm, more preferably s 300 nm, most preferably 150 150 nm, and most preferably 50 50 nm.
  • particle size herein is meant, unless otherwise stated, the average particle diameter.
  • Silanes have proven to be particularly suitable as binders. Particularly suitable are tetra-alkoxysilanes and in particular tetra-ethyl-ortho-silicates (TEOS).
  • TEOS tetra-ethyl-ortho-silicates
  • the silanes preferably have a SiCVAnteil of 5 to 70 mol%, preferably from 10 to 50 mol% and in particular from 15 to 30 mol%.
  • solvents for example for applying the photocatalytic material to a substrate, preference is given to using alcohols, in particular primary, secondary and tertiary alcohols, and also water and mixtures thereof. Particular preference is given to using primary alcohols, in particular methanol, ethanol or propanol.
  • compositions intended for applying the photocatalytic material to a substrate furthermore preferably comprise surfactants.
  • surfactants prevent agglomeration of the active particles, so that the composition can be applied by spraying, for example.
  • the process according to the invention is preferably carried out with light having a wavelength of 400 nm to 800 nm.
  • the method according to the invention for fine dust reduction is carried out in an open system.
  • An open system is characterized in particular by the fact that the normal air circulation is sufficient.
  • the photocatalytically active coatings come out with little to no UV light.
  • Other requirements that must be met by an open system are health safety of the coating and abrasion resistance.
  • closed systems no external energy must be supplied to an open system and there is no forced guidance of air flows, as is the case with closed systems, for example air conditioning systems.
  • closed systems the photocatalytically active surfaces are inside a device.
  • the pollutant-laden atmosphere, such as gases or bioaerosols are passed by forced air flow to these surfaces.
  • the placement of the surfaces inside the device in closed systems has the advantage that they can be irradiated with strong, harmful UV light. However, such irradiation is not required according to the invention.
  • the open coating systems preferred according to the invention do not require forced air guidance and no irradiation with wavelengths and / or intensities of electromagnetic radiation harmful to human health.
  • fine dusts can be removed from gaseous media, in particular from air.
  • these are in particular particles that are in the air in Floating state, so in particular particles with a mean particle diameter of 50 pounds ⁇ .
  • the fine dust particles having a size of -S 40 ⁇ on.
  • pollen grains were also understood according to the invention which could also be successfully separated from air. Pollen grains usually have an average particle diameter of 10 pm to 30 pm.
  • the photocatalytic material is applied to a substrate for the inventive method, which is then brought into contact with the gaseous medium.
  • Suitable substrates are, for example, glass, plastic, textile structures, masonry, concrete, metal, ceramic, wood or / and composite materials. Particular preference is given to using glass as the substrate.
  • a photocatalytic material which is also active without UV light, fine dust can be separated continuously and without further measures.
  • the photocatalytically active coatings are preferably used indoors, such as private living spaces, public buildings, hospitals, schools, etc. or in vehicles such as buses, passenger compartments of cars and trucks, watercraft or aircraft.
  • the application of the photocatalytic material to the substrate can be carried out by conventional methods, for example by spraying, rolling, painting, spraying, dip coating or vapor deposition.
  • the present invention further includes a photocatalyst which is active without UV light.
  • the photocatalyst has one or more elements selected from Sn, Zn, Ta, Bi, In, V, W, Sb, Ge, Ga, Tl or / and Ti, in particular Sn and / or Zn.
  • a photocatalyst comprising SnO 2 , ZnO or mixtures thereof.
  • Particularly preferred is a photocatalyst doped with one or more elements selected from Co, C, N, P, S or H.
  • Particularly preferred is a photocatalyst doped with Co, C and / or N, most preferably Co.
  • the photocatalyst according to the invention comprises Co-doped ZnO.
  • the weight ratio of Zn: Co is preferably 8: 1 to 12: 1, in particular 9: 1 to 11: 1.
  • the photocatalyst according to the invention may be loaded with one or more elements, in particular selected from Au, Ag, Pt, Al, Cu, Sb, Mo or Cd. Most preferred is a loading of Au or / and Pt.
  • a photocatalytic material comprising such a photocatalyst and a binder, wherein the binder is selected from silanes.
  • the binder preferably comprises tetra-alkoxysilanes and in particular tetra-ethyl-ortho-silicates (TEOS).
  • TEOS tetra-ethyl-ortho-silicates
  • the S1O2 content of the silane is preferably 5 to 70 mol%, preferably 10 to 50 mol%, and more preferably 15 to 30 mol%.
  • fine dust is separated from air by means of a photocatalytic material applied to glass panes without UV light.
  • the photocatalyst preferably has particle sizes of less than 300 nm in order to be transparent to the human eye.
  • Figure 1 shows XRD analyzes of SnQr samples.
  • Figure 2 shows XRD analyzes of ZnO samples.
  • FIG. 3 shows an XRD measurement of Co-doped ZnO. The incorporation of Co into the crystal structure of ZnO is clearly visible.
  • FIG. 4 shows a scanning electron micrograph of Co-doped ZnO particles.
  • ZnO was doped with Co by two different methods, namely wet-chemical and thermal.
  • EDX energy-dispersive X-ray analysis
  • the particle sizes of the photocatalyst obtained are in a range of about 100 nm to 1.2 ⁇ (mean particle diameter), as determined by scanning electron microscopy (SEM) (see Figure 4). On the basis of cathodoluminescence measurements it could be confirmed that almost all ZnO was converted.
  • the two ZnO-doped photocatalytic materials once wet-chemically and once thennically doped were applied as coatings to substrates. Fine dust reduction measurements resulted in a reduction of fine dusts after 30 minutes to 8% and 6.35%, respectively. In the case of control measurements without the photocatalytically active material according to the invention, the corresponding final value was significantly higher, namely at 15.84%. This shows that with the photocatalytic active coatings according to the invention air purification processes can be significantly accelerated.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Catalysts (AREA)

Abstract

L'invention concerne un procédé de réduction de particules fines au moyen d'un photocatalyseur, ainsi qu'un photocatalyseur qui est actif même en l'absence de lumière ultraviolette.
PCT/EP2012/065968 2012-07-11 2012-08-15 Matière à action photocatalytique pour purifier l'air WO2014008953A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
EP12175952.6 2012-07-11
EP12175952 2012-07-11
EPEP12178074 2012-07-26
EP12178074 2012-07-26

Publications (1)

Publication Number Publication Date
WO2014008953A1 true WO2014008953A1 (fr) 2014-01-16

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6387844B1 (en) * 1994-10-31 2002-05-14 Akira Fujishima Titanium dioxide photocatalyst
US20090093359A1 (en) * 2004-10-27 2009-04-09 Suminoe Textile Co., Ltd. Fiber Fabric Having VOC Removing Function
US20090192032A1 (en) * 2008-01-29 2009-07-30 Seoul National University Industry Foundation Visible light-responsive photocatalyst composition containing tungsten-based oxides and method of producing the same
US20110142725A1 (en) * 2009-12-10 2011-06-16 Honeywell International Inc. Air purification apparatus and method of forming the same
EP2407236A1 (fr) * 2010-07-13 2012-01-18 Theta Chemicals Limited Catalyseur comprenant un matériau dopé

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6387844B1 (en) * 1994-10-31 2002-05-14 Akira Fujishima Titanium dioxide photocatalyst
US20090093359A1 (en) * 2004-10-27 2009-04-09 Suminoe Textile Co., Ltd. Fiber Fabric Having VOC Removing Function
US20090192032A1 (en) * 2008-01-29 2009-07-30 Seoul National University Industry Foundation Visible light-responsive photocatalyst composition containing tungsten-based oxides and method of producing the same
US20110142725A1 (en) * 2009-12-10 2011-06-16 Honeywell International Inc. Air purification apparatus and method of forming the same
EP2407236A1 (fr) * 2010-07-13 2012-01-18 Theta Chemicals Limited Catalyseur comprenant un matériau dopé

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