CA3040960A1 - Leung's gauze for treatment of vocs and formaldehyde contaminations - Google Patents

Abstract

The Leung' s Gauze of the present invention comprising essentially of a stainless steel gauze coated with the following mentioned photocatalytic solution. The photocatalytic solutions of the present invention comprise essentially of about 0-10 weight % of Nano-Grade Metal Oxides, about 0-1 weight % of Thickening Agent, about 0-3 weight % of Quaternary Ammonium Bromide, about 0-5 weight % of Organic Acid (1), about 0-5 weight % of Organic Acid (2), about 0-8 weight % of Alkylene Glycol, and about 80-95 Weight % of Distilled Water.
The whole set up can effectively eliminate the VOCs, including Formaldehyde, through the destruction or transformation of VOCs to innocuous end-products, i.e. CO2 and H2O.

Description

Leung's Gauze For Treatment of VOCs and Formaldehyde Contaminations Background of Invention:
1. Field of Invention The present invention is related to the metal gauze coated with a novel photocatalytic solution, which could effectively eliminate the VOCs, including Formaldehyde, when contacted. Volatile Organic Compounds (VOCs) are the major group of indoor air pollutants, which significantly impact indoor air quality and influence human health. Photocatalytic Oxidation is a cost-effective technology for VOCs removal, compared with adsorption, biofiltration, or thermal catalysis method. Development of active photocatalyst systems is crucial for the Photocatalytic Oxidation reaction. Among a large number of engineered nano metal oxides, ZnO
(nano-particles) is of particular interest.

2. Description of Prior Art In today's life, indoor air pollutions have drawn a global attention regarding the improvement of indoor air quality. Indoor air pollutants mainly include Nitrogen Oxides (NO), Carbon Oxides (CO and CO2), VOCs and Particulates. Among the pollutions, VOCs are prominent representative indoor pollutants of which, Acetone (C3H60), 1-Butanol (C4H100), Butyraldehyde (C4H80), m-Xylene (C8H10) could be converted to harmless CO2 and H20 through Heterogeneous Photocatalytic Oxidation as revealed by Peral and 011is [Journal of Catalysis, 136, 554-565, 1991].
Another VOC, i.e. Trichloroethylene (C2HC13) was studied by Jacoby, Blake and Noble [Journal of Catalysis, 157, 87-96, 1995], whom described the kinetics of the oxidation of Trichloroethylene in air via heterogeneous photocatalysis.

Obee and Brown [Environmental Science and Technology, 29, 1223-1231, 1995]
reported the effects of humidity and traces contaminant levels on the oxidation rates of 1,3-Butadiene (C41-16), Toluene (C6H5CH3), and Formaldehyde (CH20) by TiO2 Photocatalysis.
VOCs are known to have long term effects on humans and considered to be carcinogenic, mutagenic, or teratogenic, as reported by Tsoukleris, Maggos and Vassilakos et al. [Catalyst Today, 129, 96-101, 2007].
Moreover, Derwent, Jenkin and Saunders et al. [Atmospheric Environment, 37, 1983-1991, 2003] studied some VOCs emissions and reported that these emissions can contribute to the formation of urban smog and ozone, stratospheric ozone depletion and the greenhouse effect.
With the increasing concerns on the indoor air quality, the degradation of VOCs has easily become the main point of research efforts in today's scientific world.
JPH09225322 discloses compositions containing nano- TiO2 that could decompose environmental pollutants in water and air.
US20130156649A1 describes the construction of the "Purification Unit and Deodoriding Device", of which nano- TiO2 was deployed as the active ingredient.
TiO2 is the most popular photocatalyst currently employed due to the hydrophilic properties of TiO2 and its ability to degrade a wide range of inorganic and organic compounds under irradiation of UV or near UV-light. The development of new photocatalysts appeared therefore to be a necessity to push forward the current photocatalytic performances. A
lot of researches are currently conducted to find out new materials and/or improve the properties of the current ones.
This invention focuses on the enhancing strategies to boost the photocatalytic efficiency of the two most common photocatalysts, TiO2 and ZnO.

Summary of the Invention The present invention provides a metal gauze coated with a photocatalytic solution composition for use in removal of harmful organic volatile chemical substances, bacteria and mould, comprising:
(a) about 0 to 10 Wt % of Nano-Grade Metal Oxides (b) about 0 to 1 Wt % of Thickening Agent (c) about 0 to 3 Wt % of Quaternary Ammonium Bromide (d) about 0 to 5 Wt % of Organic Acid (1) (e) about 0 to 5 Wt % of Organic Acid (2) (f) about 0 to 8 Wt % of Alkylene Glycol (g) about 89 to 95 Wt % of Distillated Water The composition solution can be sprayed directly onto any cleaned metal gauze surfaces, which boasts great self-cleaning power in the presence of sun light, known as "Photocatalysis".
Photocatalysis is the acceleration of a photoreaction in the presence of a catalyst. In catalyzed photolysis, light is absorbed by an adsorbed substrate. The process, photocatalytic activity (PCA), depends on the ability of the catalyst to create electron-hole pairs, which generate free radicals (e.g. hydroxyl radicals: -OH) able to undergo secondary reactions.
Its practical application was made possible by the discovery of water electrolysis by means of the nano-particles (Zn0).

3 Harmless co, (wa) arimfut 400, Light orearlm Paiiutarit P od tool PholocstAtill 1'0 0 r (7n0) 41\P:7Ott * Eiectron Moreover, Volatile Organic Compounds (VOCs), including Formaldehyde, are the major pollutants in indoor air, which significantly impact indoor air quality and thus influencing human health. A long-term exposure to these VOCs will be detrimental to human health causing sick building syndrome (SBS). Photocatalytic Oxidation of VOCs is a cost-effective technology for VOCs removal compared with adsorption, biofiltration, or thermal catalysis.
Researchers have developed a method for keeping walls and windows clean without human intervention. The key to these self-cleaning surfaces are photocatalysts, substances that mediate chemical reactions and are activated by light energy. When organic matter comes into contact with a photocatalyst, it is oxidized at an increased rate and decomposes into water and carbon dioxide. In layman's terms, the VOC contaminants come into contact with the photocatalyst, they would be destroyed and turned to carbon dioxide and water.
This property enables photocatalyst-coated surfaces to break down any organic dirt that contact to them.

4 Description of the preferred Embodiment The present invention describes a metal gauze coated with the photocatalytic solution compositions for treatment of VOCs and Formaldehyde contaminations. The characteristics of the inventive composition include its non-toxic nature, greater efficiency in terms of rate of disrupting contaminants' molecular structure, more rapid reaction toward sunlight, and improved safety due to the low vapor pressure.
The preferred metal gauze is made of stainless steel (304 or 316) with meshes from 0.5mm to 3mm. Of which, the said photocatalytic solution would be coated on it.
The preferred Nano-Grade Metal Oxide (particle size between 10nm-200nm), which is white color powder. When dispersed totally in solution, it is colorless. The photocatalytic solution preferably comprise from about 0 wt % to about 10 wt % of nano-grade Metal Oxide, more preferably from about 1 wt % to 5 wt % of Metal Oxide.
The preferred Nano-Grade Metal Oxide is preferred to be Zinc Oxide in 0 wt %
to 100 wt %, respectively.
The photocatalytic solution preferably comprise from about 0 wt % to about 1 wt % of Thickening Agent. The Thickening Agent can be selected from Guar Gum, Bentonite, Corn Starch or Food Grade Flour. The preferred Thickening Agent is preferred to be Guar Gum from about 0.01 wt % to 0.5 wt % of Guar Gum.
The photocatalytic solution preferably comprise from about 0 wt % to about 3 wt % of Quaternary Ammonium Bromide as surface active agent, is more preferably Cetyl Trimethyl Ammonium Bromide, which is a cationic surfactant with anti-bacteria function.
The preferred Cetyl Trimethyl Ammonium Bromide is more preferred to be from about 0.1 wt %
to 1 wt %.

The preferred Organic Acid (1), which is transparent liquid. The photocatalytic solution preferably comprise from about 0 wt % to about 5 wt % of Organic Acid, more preferably from about 1 wt % to 5 wt %. The preferred Organic Acid is preferred to be Acetic Acid, Formic Acid or mixed Acetic Acid and Formic Acid in 0 wt % to 100 wt %, respectively.
The preferred Organic Acid (2), which is white powder. The photocatalytic solution preferably comprise from about 0 wt % to about 5 wt % of Organic Acid, more preferably from about 1 wt % to 5 wt %. The preferred Organic Acid is preferred to be Citric Acid, Oxalic Acid or mixed Citric Acid and Oxalic Acid in 0 wt % to 100 wt %, respectively.
The photocatalytic solution preferably comprise from about 0 wt % to about 8 wt % of Alkylene Glycol with high affinity of hydroscopic property, is more preferably Propylene Glycol, which possesses water liking function. The preferred Propylene Glycol is more preferred to be from about 0.5 wt % to 3 wt %.
The photocatalytic solution of the present invention also comprises 89 wt % to 95 wt %
of Distilled Water as aqueous media, which forms nano-micelle with the metal oxide, more preferably from 90 wt % to 95 wt %.
All of the above inventive photocatalytic solution compositions are suitable for the removal of the airborne pollutants.
It is to be understood that the invention is not limited in its application to the details of the removal of airborne pollutants. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood, that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting.

As such, those skilled in the art will appreciate that the conception, upon which this disclose is based, may readily be utilized as a basis for designing other chemical compositions, formulae and fuels for carrying out the several purposes of the present invention. And the abstract of the present invention is just an abstract, not intended to be limiting as to the scope of the invention in any way.

Claims (10)

Claims:

1. A metal gauze, made of 304 or 316 stainless steel, with mesh of 0.5mm to 3mm, is used as substrate to be coated with the photocatalytic solution.

2. A photocatalytic solution composition for use in removal of harmful organic volatile chemical substances, bacteria and mould, comprising:
(a) about 0 to 10 Wt % of Nano-Grade Metal Oxides (b) about 0 to 1 Wt % of Thickening Agent (c) about 0 to 3 Wt % of Quaternary Ammonium Bromide (d) about 0 to 5 Wt % of Organic Acid (1) (e) about 0 to 5 Wt % of Organic Acid (2) (f) about 0 to 8 Wt % of Alkylene Glycol (g) about 89 to 95 Wt % of Distillated Water

3. The photocatalytic solution compositions according to claim 2(a), wherein said Nano-Grade Metal Oxide is Zinc Oxide in 0 wt % to 100 wt %, respectively.

4. The photocatalytic solution compositions according to claim 2(b), wherein said Thickening Agent is Guar Gum or Bentonite or Corn Starch or Food Grade Flour or a mixture thereof.

5. The photocatalytic solution composition according to claim 2(c), wherein, said Quaternary Ammonium Bromide is consisted of Cetyl Trimethyl Ammonium Bromide.

6. The photocatalytic solution composition according to claim 2(d), wherein, said Organic Acid (1) is Acetic Acid or Formic Acid or a mixture thereof.

7. The photocatalytic solution composition according to claim 2(e), wherein, said Organic Acid (2) is Citric Acid or Oxalic Acid or a mixture thereof.

8. The photocatalytic solution composition according to claim 2(f), wherein, said Alkylene Glycol is selected from the group consisting of Ethylene Glycol, and or Propylene Glycol.

9. The photocatalytic solution composition according to claim 2(g), wherein, said Distillated Water is prepared by doubly distilled, or if such facility is not available, any filtered natural source of water or tap water will also do, nonetheless.

10. The metal gauze according to claim 1, can be installed as cartridge of the Deodorizing Devices.