WO2025208218A1

WO2025208218A1 - Electrocatalytic filter apparatus for a heating, ventilation and air conditioning system

Info

Publication number: WO2025208218A1
Application number: PCT/CA2025/050476
Authority: WO
Inventors: Rodney HERRING
Original assignee: Individual
Current assignee: Individual
Priority date: 2024-04-04
Filing date: 2025-04-02
Publication date: 2025-10-09
Anticipated expiration: 2026-10-04
Also published as: CA3234245A1

Abstract

An electrocatalytic filter apparatus is provided for use with one or more of a heating, ventilating, refrigerating or air conditioning unit and a power source, the electrocatalytic filter apparatus comprising: a frame including a first side and a second side, each side including at least one aperture; a water inlet which is retained by the frame; a water outlet which is retained by the frame; at least two functionalized filters which are retained by the water inlet and the water outlet, are in parallel relation and are spaced apart to define an interstitial space which is in fluid communication with the water inlet and the water outlet, the functionalized filters including fiberglass or carbon fibers, wherein the functionalized filters are functionalized with low iron oxide, iron-doped titanium dioxide nanoparticles; an anode wire mesh which is retained by the frame and is disposed between the first side of the frame and one functionalized filter; a hydrogen gas generator, which is a second wire mesh anode, is retained by the frame and is disposed beside the second side of the frame; and a cathode wire mesh which is retained by the frame and is disposed between the second wire mesh anode and the other functionalized filter and is in parallel relation with the second anode wire mesh to define a channel which is fluid communication with the water inlet and the water outlet.

Description

ELECTROCATALYTIC FILTER APPARATUS FOR A HEATING, VENTILATION AND AIR CONDITIONING SYSTEM

FIELD

The present technology is directed to an apparatus that provides superior scrubbing of air, including reducing or eliminating air-borne microbes. More specifically, it is an air filter apparatus for a heating, ventilation, refrigeration and air conditioning (HVRAC) system comprising two or more fiber layers functionalized with low iron oxide, iron doped titanium dioxide nanoparticles and electrodes.

BACKGROUND

Most filters used in HVAC systems to clean the air are passive in that air passes through and airborne contaminants are trapped by the filter. Some may have functionalized filters to improve the entrapment of airborne contaminants. For example, German Patent No. 202021103950 discloses an air conditioning composite filter having a windward side and a leeward side opposite each other and comprising: a first filter module comprising :a polyphenol-containing functional layer located on the leeward side and containing natural polyphenols; a first antibacterial filter layer located on the polyphenols containing functional layer is arranged; a first particulate filter layer which is arranged on the first antibacterial filter layer and faces the windward side; and a second filter module disposed adjacent to the first filter module and comprising: a negative air ion-containing functional layer located on the leeward side and containing negative air ion-containing ceramic powder and antibacterial nanoparticles; a second antibacterial filter layer disposed on the negative air ion-containing functional layer ; and a second particulate filter layer disposed on the second antibacterial filter layer and facing the windward side. There is no disclosure as to what the nanoparticles are or how they function. This is a passive system that entraps air-borne contaminants.

Similarly, Japanese Patent No. 2013240591 discloses an air cleaner or the like at a low price, utilizing the high antibacterial property/deodorizing property of platinum nanoparticles. A platinum nanoparticle aqueous solution, for which the stock solution of the platinum nanoparticle aqueous solution that contains platinum nanoparticles and is formed by being dissolved in one liter of water is diluted by the water of the volume of any one of 400 times, 800 times and 1 ,500 times further, is prepared. A porous filter is subjected to impregnation or the like in the diluted platinum nanoparticle aqueous solution beforehand, and then the porous filter that has absorbed the platinum nanoparticle aqueous solution is dried. The porous filter in a sheet shape has many through-holes to be a path of air of several pm, which is bent zigzag in all directions on the inside thereof. The flow of air discharged from a suction fan hits a front surface of the filter and passes through the path of each through-hole therein. Inside the path, many platinum nanoparticles having high antibacterial property/deodorizing property are present. This is a passive system that entraps air-borne contaminants.

United States Patent Application Publication No. 20180245812 discloses that a component used in an air conditioner includes a substrate and a nano-coating formed on a surface of the substrate, wherein the nano-coating includes a lower coating formed on the surface of the substrate; and an upper coating formed on the upper surface of the lower coating, a coating composition of the upper coating includes nanoparticles having a diameter of 10 nm to 30 nm, and an interval between adjacent nanoparticles among the plurality of nanoparticles located on a surface of the upper coating is 10 nm to 30 nm. Titanium dioxide nanoparticles are listed as potential nanoparticles. This is to prevent dust from adhering to surfaces in the air conditioner.

United States Patent 11470892 discloses an antimicrobial air treatment device and a method of its construction. The antimicrobial air treatment device comprises an antimicrobial metal nanoparticle mesh comprising a steel support mesh and a layer of copper nanoparticles disposed on the steel support mesh. The antimicrobial air treatment device may be in the form of a facemask or a component of a moving air filtration system such as an HVAC system, an automobile cabin air filtration system, and an air purifier. The antimicrobial air treatment device may contain one or more filtration layers of filtration medium. The method of constructing the antimicrobial air treatment device involves the preparation of the antimicrobial metal nanoparticle mesh by an electrodeposition technique. This is a passive system that provides antimicrobial air treatment. United States Patent No. 11673007 discloses a mask with at least one filtering layer that includes a fabric made of non-conductive polymer fibers embedded with nanoparticles of two different metals. The population density of the nanoparticles of the two metals on the surface of non-conductive polymer fibers is configured such that the adjacent nanoparticles of the two metals have an average distance of two micrometers or less. The two different metals are selected such that the electric field intensity generated between the nanoparticles of the two different metal through the aerosol particle inactivates the microorganisms that may be inside the aerosol particle. When an aerosol particle comes into contact with the nanoparticles of the two metals, the aerosol acts as an electrolyte between the two metal types and a potential difference and an electric field is generated, through the aerosol particle, between the nanoparticles of the two metals. This is reliant on having aerosols in the air that is being exchanged and is therefore only suited to a mask.

United States Patent No. 11213777 discloses that a filter may remove particles with an average particle size up to 2.5 pm (PM2.5) and/or other airborne pollutants, which filter has fibers of an average diameter of no more than 500 nm, the fibers of at least 90 wt. % polyacrylonitrile, relative to all fibers in the filter; and a catalyst of at least 90 wt. % TiO2, relative to all catalytic metals in the filter, dispersed onto the fibers. The fibers need not be charged. The TiC may be condensed or precipitated onto the fibers out of a liquid containing the TiC and the fibers by simple methods. The catalyst may be activated by ultraviolet (UV) irradiation to decompose particulate matter having an average particle size of 2.5 pm or less, i.e., PM2.5, and/or other airborne pollutants from air. Such filters may be implemented around areas of vehicle traffic, e.g., as elements of traffic lights, and may be used to controllably purify polluted air. This filter requires UV light to function.

Canadian Patent Application No. 3039505 discloses a method of making a visible light photo-catalyst is provided, the method comprising doping a titanium dioxide nanocrystal with iron to provide an iron-doped nanocrystal, washing the iron-doped nanocrystal with an acid to produce an acid-washed iron-doped titanium dioxide nanocrystal and rinsing the acid-washed iron-doped titanium dioxide nanocrystal to remove a residual of the acid, thereby providing a visible light photo-catalyst. The photo-catalyst is also provided, as are methods of using the photo-catalyst in remediation. A non-biological, visible light photoreactor is also disclosed. This would not be suitable for use in an HVAC system.

Canadian Patent Application No. 3,084,778 discloses a method of remediating wastewater, the method comprising substantially submersing an electrocatalytic reactor in wastewater, the electrocatalytic reactor including an anode, which is mesh and defines a first bore, a filter layer, which is porous glass, carbon fiber or poly-paraphenylene terephthalamide, the filter layer including fibers and interstitial spaces between the fibers, an iron-doped titanium dioxide film on the fibers, the film including a surface that is substantially iron oxide free, the filter layer housed within the first bore and defining a second bore, a cathode, which is housed within the second bore, is mesh and defines an inner bore, and a perforated air tube housed within the inner bore; and providing at least a voltage of at least about 3 volts to the electrocatalytic reactor, in the absence of a light source, thereby remediating wastewater. This would not be suitable for use in an HVAC system as it is specifically designed for remediating wastewater.

What is needed is an air filter apparatus for an air cleaning system that includes active filter. It would be preferable if it included an anode and a cathode wire mesh with a narrow channel therebetween. It would be further preferable if there were at least two filter layers that were functionalized with low iron oxide, iron-doped titanium oxide nanoparticles and were spaced apart to provide an interstitial space. It would be preferable if there was a hydrogen bubble generator in parallel relation with the anode and the cathode wire mesh. It would be still further preferable if the air filter apparatus included a high efficiency particulate air (HEPA) filter in parallel relation with the anode and the cathode wire mesh.

SUMMARY

The present technology is an air filter apparatus for cleaning air that is an active filter. It includes an anode wire and a cathode wire with a narrow channel therebetween. The narrow channel is defined by at least two filter layers. The filter layers are functionalized with low iron oxide, iron-doped titanium oxide nanoparticles and are spaced apart to provide an interstitial space. There is a hydrogen bubble generator in parallel relation with the anode and the cathode wire mesh. The air filter apparatus includes a high efficiency particulate air (HEPA) filter in parallel relation with the anode and the cathode wire mesh.

In one embodiment, an electrocatalytic filter apparatus is provided for use with one or more of a heating, ventilating, refrigerating or air conditioning unit and a power source, the electrocatalytic filter apparatus comprising: a frame including a first side and a second side, each side including at least one aperture; a water inlet which is retained by the frame; a water outlet which is retained by the frame; at least two functionalized filters which are retained by the water inlet and the water outlet, are in parallel relation and are spaced apart to define an interstitial space which is in fluid communication with the water inlet and the water outlet, the functionalized filters including fiberglass or carbon fibers, wherein the functionalized filters are functionalized with low iron oxide, iron-doped titanium dioxide nanoparticles; an anode wire mesh which is retained by the frame and is disposed between the first side of the frame and one functionalized filter; a hydrogen gas generator, which is a second wire mesh anode, is retained by the frame and is disposed beside the second side of the frame; and a cathode wire mesh which is retained by the frame and is disposed between the second wire mesh anode and the other functionalized filter and is in parallel relation with the second anode wire mesh to define a channel which is fluid communication with the water inlet and the water outlet.

In the electrocatalytic filter apparatus, the wire mesh anode, the wire mesh cathode and the hydrogen gas generator may consist of a ruthenium coated titanium metal.

In the electrocatalytic filter apparatus, the functionalized filters may be fiberglass functionalized filters.

The electrocatalytic filter apparatus may further comprise a high efficiency particulate air (HEPA) filter which is retained by the frame and is disposed between the second anode wire mesh and the cathode wire mesh to define a second channel which is fluid communication with the water inlet and the water outlet.

In another embodiment, a system is provided for one or more of heating, ventilating, refrigerating or air conditioning, the system comprising: a blower; an electrocatalytic functionalized filter apparatus downstream from the blower and in gaseous communication with the blower; and one or more of a heating, ventilating, refrigerating or air conditioning unit which is downstream from the electrocatalytic functionalized filter apparatus and is in gaseous communication with the electrocatalytic functionalized filter apparatus, wherein the electrocatalytic filter apparatus comprises: a frame including a first side and a second side, each side including at least one aperture; a water inlet which is retained by the frame; a water outlet which is retained by the frame; at least two functionalized filters which are retained by the water inlet and the water outlet, are in parallel relation and are spaced apart to define an interstitial space which is in fluid communication with the water inlet and the water outlet, the functionalized filters including fiberglass or carbon fibers, wherein the functionalized filters are functionalized with low iron oxide, iron-doped titanium dioxide nanoparticles; an anode wire mesh which is retained by the frame and is disposed between the first side of the frame and one functionalized filter; a hydrogen gas generator, which is a second wire mesh anode, is retained by the frame and is disposed beside the second side of the frame; and a cathode wire mesh which is retained by the frame and is disposed between the second wire mesh anode and the other functionalized filter and is in parallel relation with the second anode wire mesh to define a channel which is fluid communication with the water inlet and the water outlet.

In the system, the wire mesh anode, the wire mesh cathode and the hydrogen gas generator may consist of a ruthenium coated titanium metal.

In the system, the functionalized filters may be fiberglass functionalized filters.

In the system, the electrocatalytic filter apparatus may further comprise a high efficiency particulate air (HEPA) filter which is retained by the frame and is disposed between the second anode wire mesh and the cathode wire mesh to define a second channel which is fluid communication with the water inlet and the water outlet.

In another embodiment, a method of cleaning air in a system is provided for one or more of heating, ventilating, refrigerating or air conditioning, the method comprising: selecting the system described above; blowing uncleaned air with the blower to the electrocatalytic functionalized filter apparatus; concomitantly, flowing condensate from the for one or more of heating, ventilating, refrigerating or air conditioning unit into the water inlet; the condensate flowing down the interstitial space to provide wetted functionalized filters; the condensate flowing down the channel to provide a condensate flow; the hydrogen gas generator generating hydrogen bubbles; and passing the uncleaned air through the channel and the wetted functionalized filters, thereby cleaning the air.

The method may further comprise the hydrogen bubbles entraining particulates to provide entrained particulates.

The method may further comprise the entrained particulates being flushed from the channel to the water outlet by the condensate flow.

In another embodiment, a method of cleaning air is provided, the method comprising: selecting the electrocatalytic filter apparatus described above; urging uncleaned air into the electrocatalytic functionalized filter apparatus; concomitantly, flowing water into the water inlet; the water flowing down the interstitial space to provide wetted functionalized filters; the water flowing down the channel to provide a water flow; the hydrogen gas generator generating hydrogen bubbles; and passing the uncleaned air through the channel and the wetted functionalized filters, thereby cleaning the air.

The method may further comprise the entrained particulates being flushed from the channel to the water outlet by the water flow.

In another embodiment, a method of cleaning air is provided, the method comprising selecting the electrocatalytic filter apparatus described above; urging uncleaned air into the electrocatalytic functionalized filter apparatus; concomitantly, flowing water into the water inlet; the water flowing down the interstitial space to provide wetted functionalized filters; the water flowing down the second channel to provide a water flow; the hydrogen gas generator generating hydrogen bubbles; and passing the uncleaned air through the channel, the second channel and the wetted functionalized filters, thereby cleaning the air. The method may further comprise the hydrogen bubbles entraining particulates to provide entrained particulates.

The method may further comprise the HEPA filter blocking passage of the entrained particulates.

The method may further comprise the water flow flushing the entrained particulates from the second channel to the water outlet by the water flow.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 is a schematic of an exemplary HVAC system of the present technology.

Figure 2 is a schematic of an alternative exemplary HVAC system of the present technology.

Figure 3 is a schematic of another alternative exemplary HVAC system of the present technology.

Figure 4A is a perspective, partial sectional overview schematic of electrocatalytic filter apparatus of Figure 1 ; Figure 4B is a longitudinal sectional view of the electrocatalytic filter apparatus of Figure 4A; Figure 4C is a side view of the electrocatalytic filter apparatus; and Figure 4D is a top view of the electrocatalytic filter apparatus along line C-C (which is in the intervening zone) of Figure 4A.

Figure 5A is a schematic of the first and second upper and lower members; Figure 5B is a top view of the upper members; and Figure 5C is a top view of the electrocatalytic apparatus, with the water wicking tube and side members removed and the electrodes out of view, showing the pleater and the pleated functionalized filters.

Figure 6A is a bottom view of the water wicking tube; and Figure 6B is a top view of the drip tray.

Figure 7 is a top view, with the water wicking tube removed, of an alternative embodiment electrocatalytic filter apparatus. Figure 8A is a side view of a wire puller drawing the functionalized filters into the water wicking tube slot; Figure 8B is a top view along line B-B with the electrodes removed; and Figure 8C is a top view along line C-C.

Figure 9 is an alternative embodiment of the electrocatalytic filter apparatus of Figure 4A.

Figures 10A-C are an alternative embodiment of the electrocatalytic filter apparatus of Figure 4A. Figure 10A is a side sectional view of the electrocatalytic filter apparatus; Figure 10B is a front view of the water inlet; and Figure 10C is a perspective view of the electrocatalytic filter apparatus.

Figures 11 is an alternative embodiment of the electrocatalytic filter apparatus of Figures 10A-C.

Figure 12 is an alternative embodiment of the electrocatalytic filter apparatus of Figures 10A-C.

DESCRIPTION

Except as otherwise expressly provided, the following rules of interpretation apply to this specification: (a) all words used herein shall be construed to be of such gender or number (singular or plural) as the circumstances require; (b) the singular terms "a", "an", and "the", as used in the specification and the appended claims include plural references unless the context clearly dictates otherwise; (c) the antecedent term "about" applied to a recited range or value denotes an approximation within the deviation in the range or value known or expected in the art from the measurements method; (d) the words "herein", "hereby", "hereof", "hereto", "hereinbefore", and "hereinafter", and words of similar import, refer to this specification in its entirety and not to any particular paragraph, claim or other subdivision, unless otherwise specified; (e) descriptive headings are for convenience only and shall not control or affect the meaning or construction of any part of the specification; and (f) "or" and "any" are not exclusive and "include" and "including" are not limiting. Further, the terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. Where a specific range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limit of that range and any other stated or intervening value in that stated range, is included therein. All smaller sub ranges are also included. The upper and lower limits of these smaller ranges are also included therein, subject to any specifically excluded limit in the stated range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the relevant art. Although any methods and materials similar or equivalent to those described herein can also be used, the acceptable methods and materials are now described.

Definitions:

Physical vapour deposition - in the context of the present technology, physical vapour deposition includes, but is not limited to, magnetron sputtering, ion beam sputtering, reactive sputtering, ion assist deposition, high target utilization sputtering, pulsed laser deposition and gas flow sputtering.

Thin film - in the context of the present technology, a thin film is up to 5 microns in thickness. A film may be a partial coating, a deposit upon a surface, a complete coating or a plurality of layers. To be clear, gaps may occur where the surface below is exposed. It may be formed by, for example, but not limited to growing nanocrystals on the substrate, physical vapour deposition on the substrate or photolithography on the substrate.

Iron-doped titanium dioxide with a low iron oxide surface - in the context of the present technology, iron-doped titanium dioxide with a low iron oxide surface has about 0.1 atomic% iron to about 2.0 atomic% iron, preferably 0.25 atomic% iron to about 0.75 atomic% iron, and more preferably 0.5 atomic% iron and very small amounts of iron oxide on its surface (less than 5% of the surface being iron oxide) when viewed with X-ray photoelectron spectroscopy. Substantially iron oxide free surface - in the context of the present technology, a substantially iron oxide free surface has an iron oxide content corresponding to less than about 0.001 % atomic iron (less than .5% of the surface being iron oxide) when viewed with X-ray photoelectron spectroscopy.

Porous glass - in the context of the present technology, porous glass includes fiberglass, sintered glass and any glass formed by other means. The porous glass has interstitial spaces which can be as large as 40,000 square microns.

Fiberglass fabric - in the context of the present technology, fiberglass fabric is comprised of glass threads in a plain weave. It may have any thread count, for example, but not limited to 20 x 14 to 60 x 52, to 70 x 70 and may have a thickness, of, for example, but not limited to 3 pm 0.01 mm to 0.23 mm to 1 mm to about 5 mm, depending on the application. The thread count and the thickness of the threads determines the porosity of the end product.

Carbon fiber fabric - in the context of the present technology, carbon fiber fabric is very similar to fiberglass fabric in terms of the weave, the thread count and the thread thickness. The threads are made of long carbon fibers.

Kevlar® - in the context of the present technology, Kevlar is a fabric made from polyparaphenylene terephthalamide threads. Poly-paraphenylene terephthalamide fabric is very similar to fiberglass fabric in terms of the weave, the thread count and the thread thickness.

Heating, ventilation, refrigeration or air conditioning unit - in the context of the present technology, a heating, ventilation, refrigeration and air conditioning unit (HVRAC) is an air conditioning unit, or a heat pump or a heat pump and a heat recovery ventilator or a heat pump and an energy recovery ventilator or a refrigeration unit.

DETAILED DESCRIPTION

As shown in Figure 1 , an HVAC system, generally referred to as 10 includes a blower 12, an electrocatalytic filter apparatus 14, a heater 16, an air conditioning unit 18, a water collection tube 20, a water reservoir 22, a water delivery tube 24 and a water drain 26. It can be seen that the incoming air, which may or may not be contaminated, is urged through the electrocatalytic filter apparatus 14 by the blower 12. The filtered air enters the heater 16 and then is transferred to the air conditioning unit 18, where the temperature, humidity and pressure of the air is adjusted, resulting in conditioned air being urged from the air conditioning unit 18. Condensate from the air conditioning unit 18 is collected in the water collection tube 20 and is transported to the water reservoir 22. From there, the water travels through the water delivery tube 24 to the electrocatalytic filter apparatus 14. The water then exits the HVAC system 10 via the water drain 26.

As shown in Figure 2, an alternative embodiment HVAC system, generally referred to as 2 has a heat pump 4 rather than an air conditioning unit 18. The remainder of the system is the same as for Figure 1 . Hence moisture from the heat pump 4 is recovered and sent to the electrocatalytic filter apparatus 14.

As shown in Figure 3, in another alternative embodiment HVAC system , generally referred to as 9, there is a heat pump 4 and either a heat recovery ventilator 6 or an energy recovery ventilator 8 rather than the air conditioner 18. The remainder of the system is the same as for Figure 1 . If an energy recovery ventilator 8 is used, then both the energy recovery ventilator 8 and the heat pump 4 are in liquid communication with the electrocatalytic filter apparatus 14. In yet another embodiment, there is a refrigeration unit. The remainder of the system is the same as for Figure 1 . In another embodiment, there is one or more of a heating, ventilating, refrigerating or air conditioning unit.

An overview of the electrocatalytic filter apparatus 14 is shown in Figure 4A. Two functionalized filters, a first functionalized filter 30 and a second functionalized filter 32, extend between a water wicking tube 34 at a top end 36 and a drip tray 38 at a bottom end 40. The first and second functionalized filters 30, 32 are in parallel relation to one another and are spaced apart to define a narrow interstitial space 42. Side members 44, the water wicking tube 34 and optionally the drip tray 38 retain the first and the second functionalized filters 30, 32. The side members 44 are attached to the water wicking tube 34 and to the drip tray 38. The functionalized filters 30, 32 are preferably fiberglass fabric that has been functionalized with low iron oxide, iron-doped titanium dioxide nanoparticles. In an alternative embodiment, the functionalized filters 30,32 are made of Kevlar® fabric. In yet another embodiment, the functionalized filters 30, 32 are made of sintered glass.

As shown in Figure 4B, the water wicking tube 34 has a slot 46 sized to hold the first and second functionalized filters 30, 32 and to allow water to be wicked from the water wicking tube 34 to the first and second functionalized filters 30, 32, while inhibiting water flow. Without being bound to theory, the water that is wicked into the functionalized filters 30, 32 functions to capture airborne pollutants and to generate hydroxyl and super oxygen radicals. The air passing through the wetted, functionalized filters 30, 32 picks up hydroxyl radicals and super oxygen radicals and is cleaned.

In one embodiment, the drip tray 38 may also have a slot 48 and be tubular. In this configuration, it also contributes to retaining the first and the second functionalized filters 30, 32. A first electrode 50 of one polarity and a second electrode 52 of an opposite polarity extend substantially the exposed length (the length that is not in the slots 46, 48) of the functionalized filters 30,32. Although the electrodes appear to be on the outside of the first and the second functionalized filters 30, 32, they are within pleats, as shown in Figure 4D. A wire mesh 54, 56 extends between the side members 44, the water wicking tube 34 and the drip tray 38. The wire mesh 54, 56 further retains the first and second functionalized filters 30, 32. The wire mesh is preferably ruthenium coated titanium metal. Without being bound to theory, the ruthenium coating protects the titanium wire so it doesn't become brittle. Further, the ruthenium reduces the electrical resistivity of the titanium wire enhancing current flow through the electrocatalytic filter apparatus 14.

As shown in Figure 4C, the functionalized filters 30, 32 include an intervening zone 31 which is between an upper member 64, 74 and a lower member 66, 76. These members sit below the water wicking tube 34 where the top end 36 is housed and above the drip tray 38 where the bottom end 38 is housed, respectively.

Figure 4D is a top view of the electrocatalytic filter apparatus 14 with the water wicking tube 34 removed and in the intervening zone 31 of the functionalized filters 30, 32. The outer surface 58 of each functionalized filter 30, 32 abuts the electrodes 50, 52. It can be seen that every first electrode 50 is in every first pleat 60 and every second electrode is in every second pleat 62. The pleats 60, 62 are vertically disposed. The pleats 60, 62 abut the wire mesh 54, 56 and include both the first and the second functionalized filters 30, 32. The outer surface 58 of the first functionalized filter 30 abuts every first electrode 50 and the outer surface 58 of the second functionalized filter 32 abuts every second electrode 52.

As shown in Figure 5A, the first electrode 50 is attached to the first upper member 64 and the first lower member 66 with pins 68. The distance between the pins 68 is “x”. A series of apertures 70 are offset from the pins 68 by “Vz x”. Aligned with the pins 68 are pegs 72. The pegs 72 have a shallow slot that the first electrode 50 can be guided over it. The second electrode 52 is attached to the second upper member 74 and the second lower member 76 with pins 78. The distance between the pins 78 is “x”. A series of apertures 80 are offset from the pins 78 by “Vz x”. Aligned with the pins 78 are pegs 82. The pegs 82 have a shallow slot that the second electrode 52 can be guided over it. There are as many pegs 72 as apertures 80 and as many pegs 82 as apertures 70. It can be seen that the distance between the edge 86 of the first members 64, 66 and the first pin 68 closest to the edge 70 is “Vz x” and the distance between the edge 88 of the second members 74, 76 and the pins 78 is “x”. As shown in Figure 5B, the pegs 72 of the first members 64, 66 snap into the apertures 80 of the second members 74, 76, and the pegs 82 of the second members 74, 76 snap into the apertures 70 of the first members 64, 66 to provide a pleater, generally referred to as 89.

As shown in Figure 5C, the functionalized filters 30, 32 are pleated by the pleater 89. This results in the positioning of the electrodes 30, 32 in the pleats as shown in Figure 4C. It can be understood that the pegs 72, 82, only retain the functionalized filters 30, 32 proximate to the top end 36 and the bottom end 38, and not in the intervening zone 31 of the functionalized filters 30, 32. The pegs 72, 82 are sized to ensure that they are a length that allows the two functionalized filters 30, 32 to be close to one another and to define the interstitial space 42 which is seen between the functionalized filters 30, 32 in the intervening zone 31. Note that Figure 4D shows the relationship between the functionalized filters 30, 32 in the intervening zone 31 .

As shown in Figure 6A, the water wicking tube 34 includes the slot 46 with V or U-shaped zig zags 92. The distal end 94 is sealed with a cap 96. Similarly, as shown in Figure 6B, in one embodiment of the drip tray 38, the drip tray 38 includes the slot 48 with V or U- shaped zig zags 92. The distal end 94 is sealed with a cap 96. The slots 46, 48 are sized to hold the functionalized filters 30, 32, therefore, for example, if a fiberglass sheet of fabric is about 200 micrometers thick, the slots 46, 90 would be about 0.5 millimeters wide. The open end of the water wicking tube 34 connects with the water delivery tube 24 and the open end of the drip tray 38 connects with the water drain 26.

In an alternative embodiment shown in Figure 7, only one of the functionalized filters zig zags. Either the anode or the cathode electrodes (50 or 52) are associated with the functionalized filter 32 that zig zags and the other electrode is associated with the functionalized filter 30 that remains straight. In order to manufacture this embodiment, at least the water wicking tube 34 has two slots, one that zig zags and one that is straight.

The method of constructing the electrocatalytic filter apparatus 14 is summarized in Figures 8A-C. As shown in Figure 8A, apertures 100 are spaced apart along the length of the functionalized filters 30, 32. In an alternative embodiment, the apertures are replaced with loops or pegs. The role is to releasably attach the functionalized filters 30, 32 to a wire puller 102 or other releasable retention means of each functionalized filter 30, 32. Using the water wicking tube 34 as an example of the steps that would be taken for feeding the functionalized filters 30, 32 into one embodiment of the drip tray 38, the wire puller 102 extends through the bore of the water wicking tube 34. A user pulls the wire puller 102 along, detaches it from the aperture 100 and attaches it to the next aperture 100. This continues until the functionalized filters 30, 32 are retained in the slot 46. If the drip tray 38 has a slot 48, the functionalized filters 30, 32 are drawn into that slot 48. After constructing the pleater 89, thereby pleating the functionalized filter 30, 32 as shown in Figure 5A-C, a framework is constructed. Using the upper members 64, 74 as an example, as shown in Figure 8B, the first upper member 64 and the second upper member 74 are attached to the side members 44 and at least the water wicking tube 34. As shown in Figure 8C, the wire mesh 54, 56 is attached to the side members 44.

As shown in Figure 9, the pleater 89 is replaced with an integral upper and lower pleater 200 in the water wicking tube 34 and the drip tray 38, respectively. The pleater 200 consists of a zig zag first slot 202 and a zig zag second slot 204. The slots 202, 204 are about 250 micrometers wide with a very narrow (100 micrometers wide) zig zag divider 206 therebetween. The end cap 96 on the end 94 of the water wicking tube 34 and a perforated end cap 208 of the drip tray 38 ensure that the two functionalized filters 30, 32 are retained in the slots 202, 204. An upper member 64 and a lower member 66 remain as part of the framework and retain the pins 68. The upper member 64 and the lower member 66 are disposed between the zig zag first and second slots 202, 204 on the zig zag divider 206. In yet another alternative embodiment, the upper member 64 and the lower member 66 are integral with the zig zag divider 206. In this embodiment the framework consists of the side members 44, the water wicking tube 34 and the drip tray 38. In yet another embodiment, the pins 68 are attached to the water wicking tube 34 and the drip tray 38.

An overview of an alternative embodiment electrocatalytic filter apparatus 214 is shown in Figure 10A. Two functionalized filters, a first functionalized filter 230 and a second functionalized filter 232, are in parallel relation to one another and are spaced apart to define a narrow interstitial space 242. The functionalized filters 230, 232 are preferably fiberglass fabric that has been functionalized with low iron oxide, iron-doped titanium dioxide nanoparticles. In an alternative embodiment, the functionalized filters 230,232 are made of Kevlar® fabric. In yet another embodiment, the functionalized filters 230, 232 are made of sintered glass. An anode 250 and a cathode 252 are in electrical communication with a power source 254. A water inlet 256 is at a top end, generally referred to as 258, and a water outlet 260 is at the bottom end, generally referred to as 262. The water inlet 256 clamps the functionalized filters 230, 232 in place leaving the interstitial space 242 between them. As shown in Figure 10B, the water inlet 256 has a series of nozzles 270 along its length to ensure even distribution of water flowing in the interstitial space 242 between the functionalized filters 230, 232. Without being bound to theory, the cathode 252 produces hydroxyl radicals from the water. The water outlet 260 may be a drip tray. It clamps the functionalized filters 230, 232 in place such that the interstitial space 242 is maintained. As shown in Figures 10A and 10C, a frame 272 retains the functionalized filters 230, 232, the anode 250, the cathode 252, the water inlet 256 and the water outlet 260. The frame 272 has large apertures 274 to allow for air flow through the electrocatalytic filter apparatus 214. The frame 272 is a non-conducting, inert material, for example, but not limited to plexiglass. The frame 272 may have two sides that are bolted together or may be a sleeve. Bolts 276 hold the anode 250 and the cathode 252 in place. It can be seen that the anode 250 and the cathode 252 are wire mesh. The wire mesh is preferably ruthenium coated titanium metal. Without being bound to theory, the ruthenium coating protects the titanium so it doesn't become brittle. Further, the ruthenium reduces the electrical resistivity of the titanium mesh enhancing current flow through the electrocatalytic filter apparatus 214. This embodiment may be integrated with the HVAC system of Figures 1 -3.

An overview of an alternative embodiment electrocatalytic filter apparatus 314 is shown in Figure 11. Two functionalized filters, a first functionalized filter 330 and a second functionalized filter 332, are in parallel relation to one another and are spaced apart to define a narrow interstitial space 342. The functionalized filters 330, 332 are preferably fiberglass fabric that has been functionalized with low iron oxide, iron-doped titanium dioxide nanoparticles. In an alternative embodiment, the functionalized filters 330,332 are made of Kevlar® fabric. In yet another embodiment, the functionalized filters 330, 332 are made of sintered glass. An anode 350 and a cathode 352 are in electrical communication with a power source 354. A water inlet 356 is at a top end, generally referred to as 358, and a water outlet 360 is at the bottom end, generally referred to as 362. The water inlet 356 clamps the functionalized filters 330, 332 in place such that the interstitial space 342 is maintained. The water inlet 356 and the frame are as per Figures 10B and 10C. A hydrogen gas generator 380, which is a second anode, is in electrical communication with the power source 354. The hydrogen gas that is generated is contained between the hydrogen gas generator 354 and the cathode 352 in a channel 382 which is fluid communication with the water inlet 356 and the water outlet 360. Without being bound to theory, the hydrogen gas bubbles trap small particles including viruses, bacteria and particulate chemicals. The bubbles with entrapped particles are either captured at the cathode 352 where they pollutants are degraded by the hydroxyl radicals that are produced there, and/or are flushed through the channel 382 to the water outlet 360 by the water flow. The anode 350, the cathode 352 and the hydrogen gas generator 380 are wire mesh. The wire mesh is preferably ruthenium coated titanium metal. The ruthenium coated titanium metal of the hydrogen gas generator 380 creates smaller hydrogen bubbles than would be produced with uncoated titanium and in the range of 1.0 micrometer (pm) to 5 pm. This embodiment may be integrated with the HVAC system of Figures 1 -3.

An overview of an alternative embodiment electrocatalytic filter apparatus 414 is shown in Figure 12. Two functionalized filters, a first functionalized filter 430 and a second functionalized filter 432, are in parallel relation to one another and are spaced apart to define a narrow interstitial space 442. The functionalized filters 430, 432 are preferably fiberglass fabric that has been functionalized with low iron oxide, iron-doped titanium dioxide nanoparticles. In an alternative embodiment, the functionalized filters 430,432 are made of Kevlar® fabric. In yet another embodiment, the functionalized filters 430, 432 are made of sintered glass. An anode 450 and a cathode 452 are in electrical communication with a power source 454. A water inlet 456 is at a top end, generally referred to as 458, and a water outlet 460 is at the bottom end, generally referred to as 462. The water inlet 456 clamps the functionalized filters 430, 432 in place such that the interstitial space 442 is maintained. The water inlet 456 and the frame are as per Figures 10B and 10C. A hydrogen gas generator 480, which is a second anode, is in electrical communication with the power source 454. The anode 450, the cathode 452 and the hydrogen gas generator 480 are wire mesh. The wire mesh is preferably ruthenium coated titanium metal. A high efficiency particulate air (HEPA) filter 486 is disposed between the hydrogen gas generator 480 and the cathode 452. A standard household HEPA filter has a 5 pm rating. It is clamped in place by the frame or the water inlet 456 and water outlet 460. The hydrogen gas that is generated is contained between the hydrogen gas generator 480 and HEPA filter 486 in a channel 488 which is fluid communication with the water inlet 456 and the water outlet 460. Without being bound to theory, the hydrogen gas bubbles trap small particles including viruses, small bacteria and particulate chemicals that would otherwise pass through a HEPA filter. The hydrogen bubbles and trapped particulate material are larger than 5 pm. The water flow through the channel 488 flushes the hydrogen bubbles with their trapped small particles to the water outlet 460. This embodiment may be integrated with the HVAC system of Figures 1 -3. In use, the electrocatalytic filter apparatus 14, 214, 314 is connected to a power supply which supplies a voltage of about 3 to 5 Volts. Water from the air conditioner 18 or heat pump 4 or both the heat pump 4 and the energy recovery ventilator 8 flows down the interstitial space interstitial space 42, 142, 242, 342, while air is blow through the functionalized filters 30,32, 130, 132, 230, 232, 330, 332. As the air passes through the wetted functionalized filters 30, 32 it is cleaned. Additionally, the hydrogen gas generator 380 creates small hydrogen bubbles which small particles are attracted to through Van der Waal forces. The hydrogen bubbles with entrained particulates migrate to the cathode 352 where the hydroxyl radicals break down the particulates, or the entrained particulates are flushed through the channel 382, or both.

In use, the electrocatalytic filter apparatus 414, which includes the HEPA filter 486, is connected to a power supply which supplies a voltage of about 3 to 5 Volts and up to 10 Volts. Water from the air conditioner 18 or heat pump 4 or both the heat pump 4 and the energy recovery ventilator 8 flows down the interstitial space interstitial space 442, while air is blow through the functionalized filters 430, 432. As the air passes through the wetted functionalized filters 430, 432 it is cleaned. Additionally, the hydrogen gas generator 480 creates small hydrogen bubbles in a second channel 488 which small particles are attracted to through Van der Waal forces. The particulates that are therefore entrained by the hydrogen bubbles. The entrained particulates are driven to the HEPA filter 486 by the air flow where they cannot pass through the HEPA filter 486 and are therefore flushed through the second channel 488 to the water outlet 460. Without being bound to theory, the size of the combination of the hydrogen bubbles and the entrained particulates is larger than the pore size of a standard household HEPA filter, while the size of the particulates alone, is small enough to pass through the standard household HEPA filter.

One method of preparing the low iron oxide, iron-doped titanium dioxide functionalized fiberglass or sintered glass is as follows:

The iron-doped titanium dioxide nanoparticles were prepared by the sol-gel method using titanium isopropoxide (TTIP) as the precursor and ferric nitrate (Fe(NO3)3.9H2O) as the iron source. Firstly, the desired amount of ferric nitrate (0.25, 0.5, 1 , 5 and 10 molar %) was dissolved in water and then the solution was added to 30 mL of anhydrous ethyl alcohol and stirred for 10 minutes. The acidity of the solution was adjusted to about pH 3 (about pH 2.5 to about pH 3.5) using HNO3 (other acids could also be used), which produces better Fe doped TiO2, i.e., incorporation of Fe into the TiO2 nanocrystals. Secondly, TTIP was added dropwise to the solution. Then deionized water with the ratio of Ti:H2O (1 :4) was added to the mixture. The solution was stirred for two hours, poured onto the fiberglass fabric and then dried at 80°C to form particles on the fiberglass fabric. The combination of the particles and the fiberglass fabric was then washed three times with deionized water. Next, the combination was calcined at 400°C for one hour to adhere the iron-doped titanium dioxide nanoparticles to the fiberglass fibers of the fabric, thus producing functionalized fiberglass. The functionalized fiberglass was washed in an HCI solution (acid washed) and then washed with deionized water three times. The acid washing was in a solution of about pH 2.5 to about pH 3.5, or about pH 4, with, preferably, a monoprotic acid, such as, for example, but not limited to acetic acid (CH3CO2H or HOAc), hydrochloric acid (HCI), hydroiodic acid (HI), hydrobromic acid (HBr), perchloric acid (HCIO4), nitric acid (HNO3) or sulfuric acid (H2SO4), with HCI being the preferred. Through analysis, it was shown that the nanoparticles bind to the fiberglass fibers or the sintered glass. The binding between the glass and Fe doped TiO2 is between the oxygen ions and not between Si and Ti ions.

A second method of preparing the low iron oxide, iron-doped titanium dioxide functionalized fiberglass or sintered glass is as follows:

The low iron oxide, iron-doped titanium dioxide nanoparticles were prepared by the solgel method using titanium isopropoxide (TTIP) as the precursor and ferric nitrate (Fe(NO3)3.9H2O) as the iron source. Firstly, the desired amount of ferric nitrate (0.25, 0.5, 1 , 5 and 10 molar%) was dissolved in water and then the solution was added to 30 mL of anhydrous ethyl alcohol and stirred for 10 minutes. The acidity of the solution was adjusted to about pH 3 (about pH 2.5 to about pH 3.5) using HNO3 (other acids could also be used), which produces better Fe doped TiO2, i.e., incorporation of Fe into the TiO2 nanocrystals. Secondly, TTIP was added dropwise to the solution. Then deionized water with the ratio of Ti:H2O (1 :4) was added to the mixture. The solution was stirred for two hours and then dried at 80°C for two hours. The powders were then washed three times with deionized water. Next, the powder was calcined at 400°C for three hours. The calcined powder was stirred in an HCI solution (acid washed) and then washed with deionized water three times. The acid washing was in a solution of about pH 2.5 to about pH 3.5, or about pH 4, with, preferably, a monoprotic acid, such as, for example, but not limited to acetic acid (CH3CO2H or HOAc), hydrochloric acid (HCI), hydroiodic acid (HI), hydrobromic acid (HBr), perchloric acid (HCIO4), nitric acid (HNO3) or sulfuric acid (H2SO4), with HCI being the preferred. The acid washing produced low iron oxide, iron-doped titanium dioxide. The low iron oxide, iron-doped titanium dioxide nanoparticles were suspended in water and either sprayed onto the fiberglass fabric or sintered glass, or the fiberglass fabric or sintered glass was immersed in the water. The combination of the fiberglass fabric and the low iron oxide, iron-doped titanium dioxide nanoparticles were calcined at 400°C for four hours to adhere the low iron oxide, iron-doped titanium dioxide nanoparticles to the fiberglass fibers of the fabric, thus producing functionalized fiberglass. Through analysis, it was shown that the nanoparticles bind to the fiberglass fibers. The binding between the glass and Fe doped TiO2 is between the oxygen ions and not between Si and Ti ions.

Regardless of the method of producing the low iron oxide, iron-doped titanium dioxide nanoparticle functionalized fiberglass fabric, the acid washing was shown to remove a significant amount of iron oxide from the surface of the nanoparticles. The acid-washed iron-doped titanium dioxide nanoparticles function as electrocatalysts. The iron-doped titanium dioxide nanoparticles adhere tightly to the fiberglass, sintered glass or carbon fibers of the functionalized filters. The nanoparticles do not occlude the interstitial spaces in the fabric of the filters, allowing air to flow through.

While the technology has been described in detail, such a description is to be considered as exemplary and not restrictive in character and is to be understood that it is the presently preferred embodiments of the present technology and is thus representative of the subject matter which is broadly contemplated by the present technology, and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.

Claims

1. An electrocatalytic filter apparatus for use with one or more of a heating, ventilating, refrigerating or air conditioning unit and a power source, the electrocatalytic filter apparatus comprising: a frame including a first side and a second side, each side including at least one aperture; a water inlet which is retained by the frame; a water outlet which is retained by the frame; at least two functionalized filters which are retained by the water inlet and the water outlet, are in parallel relation and are spaced apart to define an interstitial space which is in fluid communication with the water inlet and the water outlet, the functionalized filters including fiberglass or carbon fibers, wherein the functionalized filters are functionalized with low iron oxide, iron-doped titanium dioxide nanoparticles; an anode wire mesh which is retained by the frame and is disposed between the first side of the frame and one functionalized filter; a hydrogen gas generator, which is a second wire mesh anode, is retained by the frame and is disposed beside the second side of the frame; and a cathode wire mesh which is retained by the frame and is disposed between the second wire mesh anode and the other functionalized filter and is in parallel relation with the second anode wire mesh to define a channel which is fluid communication with the water inlet and the water outlet.

2. The electrocatalytic filter apparatus of claim 1 , wherein the wire mesh anode, the wire mesh cathode and the hydrogen gas generator consist of a ruthenium coated titanium metal.

3. The electrocatalytic filter apparatus of claim 1 or 2, wherein the functionalized filters are fiberglass functionalized filters.

4. The electrocatalytic filter apparatus of any one of claims 1 to 3, further comprising a high efficiency particulate air (HEPA) filter which is retained by the frame and is disposed between the second anode wire mesh and the cathode wire mesh to define a second channel which is fluid communication with the water inlet and the water outlet.

5. A system for one or more of heating, ventilating, refrigerating or air conditioning, the system comprising: a blower; an electrocatalytic functionalized filter apparatus downstream from the blower and in gaseous communication with the blower; and one or more of a heating, ventilating, refrigerating or air conditioning unit which is downstream from the electrocatalytic functionalized filter apparatus and is in gaseous communication with the electrocatalytic functionalized filter apparatus, wherein the electrocatalytic filter apparatus comprises: a frame including a first side and a second side, each side including at least one aperture; a water inlet which is retained by the frame; a water outlet which is retained by the frame; at least two functionalized filters which are retained by the water inlet and the water outlet, are in parallel relation and are spaced apart to define an interstitial space which is in fluid communication with the water inlet and the water outlet, the functionalized filters including fiberglass or carbon fibers, wherein the functionalized filters are functionalized with low iron oxide, iron-doped titanium dioxide nanoparticles; an anode wire mesh which is retained by the frame and is disposed between the first side of the frame and one functionalized filter; a hydrogen gas generator, which is a second wire mesh anode, is retained by the frame and is disposed beside the second side of the frame; and a cathode wire mesh which is retained by the frame and is disposed between the second wire mesh anode and the other functionalized filter and is in parallel relation with the second anode wire mesh to define a channel which is fluid communication with the water inlet and the water outlet.

6. The system of claim 5, wherein the wire mesh anode, the wire mesh cathode and the hydrogen gas generator consist of a ruthenium coated titanium metal.

7. The system of claim 5 or 6, wherein the functionalized filters are fiberglass functionalized filters.

8. The system of any one of claims 5 to 7, wherein the electrocatalytic filter apparatus further comprises a high efficiency particulate air (HEPA) filter which is retained by the frame and is disposed between the second anode wire mesh and the cathode wire mesh to define a second channel which is fluid communication with the water inlet and the water outlet.

9. A method of cleaning air in a system for one or more of heating, ventilating, refrigerating or air conditioning, the method comprising: selecting the system of claim 5; blowing uncleaned air with the blower to the electrocatalytic functionalized filter apparatus; concomitantly, flowing condensate from the for one or more of heating, ventilating, refrigerating or air conditioning unit into the water inlet; the condensate flowing down the interstitial space to provide wetted functionalized filters; the condensate flowing down the channel to provide a condensate flow; the hydrogen gas generator generating hydrogen bubbles; and passing the uncleaned air through the channel and the wetted functionalized filters, thereby cleaning the air.

10. The method of claim 9, further comprising the hydrogen bubbles entraining particulates to provide entrained particulates.

11 . The method of claim 11 , further comprising the entrained particulates being flushed from the channel to the water outlet by the condensate flow.

12. A method of cleaning air, the method comprising: selecting the electrocatalytic filter apparatus of claim 1 ; urging uncleaned air into the electrocatalytic functionalized filter apparatus; concomitantly, flowing water into the water inlet; the water flowing down the interstitial space to provide wetted functionalized filters; the water flowing down the channel to provide a water flow; the hydrogen gas generator generating hydrogen bubbles; and passing the uncleaned air through the channel and the wetted functionalized filters, thereby cleaning the air.

13. The method of claim 12, further comprising the hydrogen bubbles entraining particulates to provide entrained particulates.

14. The method of claim 13, further comprising the entrained particulates being flushed from the channel to the water outlet by the water flow.

15. A method of cleaning air, the method comprising selecting the electrocatalytic filter apparatus of claim 4; urging uncleaned air into the electrocatalytic functionalized filter apparatus; concomitantly, flowing water into the water inlet; the water flowing down the interstitial space to provide wetted functionalized filters; the water flowing down the second channel to provide a water flow; the hydrogen gas generator generating hydrogen bubbles; and passing the uncleaned air through the channel, the second channel and the wetted functionalized filters, thereby cleaning the air.

16. The method of claim 15, further comprising the hydrogen bubbles entraining particulates to provide entrained particulates.

17. The method of claim 16, further comprising the HEPA filter blocking passage of the entrained particulates.

18. The method of claim 17, further comprising the water flow flushing the entrained particulates from the second channel to the water outlet by the water flow.