HK40013161A - Purified hydrogen peroxide gas generation methods and devices - Google Patents

Description

Method and apparatus for generating purified hydrogen peroxide gas

RELATED APPLICATIONS

This application is a divisional application of an invention patent application, the filing date of which is 2015, 5 months and 5 days, application number 201580036730.X (PCT/US2015/029276), entitled "method and apparatus for generating purified hydrogen peroxide gas". This application claims priority to U.S. provisional application No. 61/988,535, filed 5/2014, which is incorporated herein by reference in its entirety.

Technical Field

The present disclosure relates generally to improved methods and apparatus for producing Purified Hydrogen Peroxide Gas (PHPG). More particularly, the present disclosure relates to improved gas permeable surfaces, catalytic surfaces, and methods for increasing PHPG production.

Background

Pathogenic microorganisms, molds (molds), mildews (milews), spores, and organic and inorganic contaminants are common in the environment. Microbial control and disinfection in environmental spaces is desirable for improving health. Many approaches have been used in the past to attempt to sanitize air and disinfect surfaces. For example, Reactive Oxygen Species (ROS), generated by, for example, photocatalytic oxidation processes, are known to oxidize organic pollutants and kill microorganisms. More particularly, hydroxyl radicals, hydroperoxyl radicals, chlorine, and ozone, the end products of photocatalytic reactions, are known to be capable of oxidizing organic compounds and killing microorganisms. However, known methods and devices are limited not only by efficacy limitations but also by safety issues.

ROS is a term used to describe highly activated air produced by exposure of ambient humid air to ultraviolet light. Light in the ultraviolet range emits photons at a frequency that, when absorbed, has sufficient energy to break chemical bonds. Ultraviolet light at wavelengths of 250-255 nm is commonly used as a biocide. Light below about 181 nm up to 182-187 nm can compete with corona discharge in its ability to generate ozone. Both ozonation and ultraviolet radiation are used for disinfection in community water systems. Ozone is currently used in the treatment of industrial wastewater and cooling towers.

Hydrogen peroxide is well known for its antimicrobial properties and has been used in aqueous solutions for disinfection and microbial control. However, attempts to use hydrogen peroxide in the gas phase have been hampered in the past by the technical hurdles to the production of Purified Hydrogen Peroxide Gas (PHPG). The vaporized aqueous hydrogen peroxide solution produces a fine droplet aerosol composed of aqueous hydrogen peroxide solution. Various methods for "drying" Vaporized Hydrogen Peroxide (VHP) solutions produce, at best, hydrated forms of hydrogen peroxide. These hydrated hydrogen peroxide molecules are surrounded by water molecules that are bound by electrostatic attraction and london forces. Thus, the ability of hydrogen peroxide molecules to electrostatically interact directly with the environment is greatly reduced by the bound molecular water, which strongly alters the basic electrostatic configuration of the encapsulated hydrogen peroxide molecules. Furthermore, the minimum achievable concentration of vaporized hydrogen peroxide is typically well above the 1.0 ppm Occupancy Safety and Health Administration (OSHA) workplace safety limit, making these approaches unsuitable for use in occupied areas.

Photocatalysts that have been demonstrated to destroy organic contaminants in fluids include, but are not limited to, TiO₂、ZnO、SnO₂、WO₃、CdS、ZrO₂、SB₂O₄And Fe₂O₃. Titanium dioxide is chemically stable, has a bandgap suitable for UV/visible light activation and is relatively inexpensive. Thus, the photocatalytic chemistry of titanium dioxide for the removal of organic and inorganic compounds from contaminated air and water has been extensively studied over the last three decades.

Since photocatalysts can generate hydroxyl radicals from adsorbed water when activated by uv light of sufficient energy, they appear promising for the production of PHPG for release into the environment when applied in the gas phase. However, current applications of photocatalysts have focused on generating plasmas containing many different reactive chemical species. Furthermore, most chemical species in the photocatalytic plasma can react with hydrogen peroxide and inhibit the production of hydrogen peroxide gas by virtue of the reaction that destroys hydrogen peroxide. Any organic gases introduced into the plasma also inhibit hydrogen peroxide production by direct reaction with hydrogen peroxide and by reaction of their oxidation products with hydrogen peroxide.

The photocatalytic reactor itself also limits the production of PHPG for release into the environment. Since hydrogen peroxide has a chemical potential higher than that of oxygen to be reduced as a sacrificial oxidant, it is preferentially reduced as fast as it is generated by oxidation of water as it moves downstream in the photocatalytic reactor.

TABLE 1 Oxidation/reduction half-reactions

Photoactivation of catalysts	Standard reduction potential (eV)
		hν h+ + e−(in TiO)2On the catalyst)	≤ -3.2
hν h+ + e−(in TiO with a promoter)2On the catalyst)	≤ -2.85
Loss of free electrons due to electron-hole recombination
		h+ + e− Heat (in TiO)2On the catalyst)	≥ 3.2
h+ + e− Heat (in TiO with a promoter)2On the catalyst)	≥ 2.85
Formation of hydroxyl radicals (only when water is adsorbed on the active sites on the catalyst to prevent electron-hole recombination)
		h+ + H2O OH* + H+	2.85
		Thermodynamically favourable loss of hydroxyl radicals by reduction of free electrons in a concentrated plasma reactor, but obtained in a PHPG reactorAvoid
OH* + e− + H+ H2O	2.02
The hydroxyl radicals combine to form hydrogen peroxide, which is non-thermodynamically favored in a plasma reactor compared to free electron reduction, but by a PHPG reactorFacilitated by creating a dilute hydroxyl radical field that separates from free electrons
		2OH* H2O2	1.77
		Any hydrogen peroxide is destroyed in the concentrated plasma reactor, but is made available by the PHPG reactor by creating dilute hydroxyl radicals that are separated from free electrons and lightFree radical field and spontaneous reaction avoided
2OH* + H2O2 2H2O + O2	2.805
		H2O2 + 2 H+ + 2 e− 2H2O	1.78
H2O2 + hν 2OH (by photolysis)	1.77
		e− + H2O2 OH* + OH-	0.71
		Reactions in which hydrogen peroxide is produced by forced reduction of dioxygen (dioxygen) in a PHPG reactor, but not in a concentrated plasma reactor
e− + O2 O2 −(the first step is not spontaneous)	- 0.13
		2H+ + 2e− + O2 H2O2(Total reaction)	0.70
		Other reactions common in concentrated plasma reactors but not occurring in PHPG reactors that do not use wavelengths of light that generate ozone
O2 + hν2O (by photolysis)	≤ -5.13
		2O* + 2O2 2O3	2.99
O3 + 2 H+ + 2 e− O2(g) +  H2O	2.075
		O3 +  H2O + 2 e− O2(g) +  2 OH-	1.24
		Ozone destruction of hydrogen peroxide
O3 + H2O2 H2O + 2O2	1.381

In addition, several side reactions generate various species that become part of the photocatalytic plasma and inhibit the production of PHPG for release into the environment as described above.

Hydroxyl radicals are generally generated by oxidation of water and require an oxidation potential of at least 2.85 eV to occur. The catalyst must therefore be activated by photons having at least this required energy. Photons having energies below 2.85 eV do not generate hydroxyl radicals, but photons having energies of at least 1.71 eV can photolyze hydrogen peroxide into hydroxyl radicals. Due to the destruction of hydrogen peroxide, excessive light having an energy of 1.71 eV or more should be avoided.

In a plasma reactor, where free electrons have the potential to recombine with hydroxyl radicals and form hydroxide ions, this is a thermodynamically favored reaction because it has the highest reduction potential of 2.02 eV. All reactions with lower reduction potential (e.g. hydroxyl radicals combine to form hydrogen peroxide, 1.77 eV) are not favored. In the rare case where hydrogen peroxide formation occurs, a stoichiometric excess of two free electrons will be generated. In this case, a stoichiometric excess of free electrons makes it possible for lower potential reactions to occur, most particularly the reduction of hydrogen peroxide molecules to hydroxyl radicals and hydroxide ions (0.71 eV), followed by further reduction to water by separate reduction of the radicals and the ions.

In the plasma reactor, the abundance of free electrons ensures that the reduction of hydroxyl radicals predominates and that any hydrogen peroxide that may theoretically form is immediately reduced back to water.

In contrast, in a PHPG reactor, the generation of hydrogen peroxide is advantageous because the reactor separates hydroxyl radicals from free electrons to prevent the reduction of hydroxyl radicals to water. This allows the next most favorable reaction to occur, i.e. the combination of hydroxyl radicals to form hydrogen peroxide. Hydrogen peroxide can be reduced back to water by decomposition (reaction of hydrogen peroxide molecules with each other), but this effect is minimized by ensuring that the hydrogen peroxide produced is dilute.

Since the PHPG reactor separates hydroxyl radicals from the free electrons remaining on the catalyst, the free electrons are also forced to reduce another species, in this case dioxygen. The reduction of dioxygen to superoxide ion (superoxide) has a negative reduction potential of-0.13 eV, indicating that it is not spontaneous, but only slightly so. This non-spontaneity is overcome by the accumulation of free electrons on the catalyst to generate an increased thermodynamic reduction pressure. This non-spontaneous reaction is the first of four steps in the reduction of oxygen to hydrogen peroxide, the remaining three steps being spontaneous. It is important to note that when all four steps are combined into a single reduction reaction, the overall potential is positive, or spontaneous. It is easily neglected the fact that the non-spontaneous first step must occur before the remaining three spontaneous steps can ensue.

Forcing the reduction of dioxygen to hydrogen peroxide by separation of hydroxyl radicals from free electrons remaining on the catalyst (removal) of course leads to the desired generation of still more hydrogen peroxide.

The reactions listed in table 1 are the most relevant. Other reactions known in the art may be added and their relative contribution to the reaction on the catalyst surface depends on their relative potential compared to the critical reaction. Notably, another high potential reaction that destroys hydrogen peroxide is introduced, such as when ozone is formed from a plasma reactor. To avoid ozone generation altogether, it is only necessary to avoid the use of light at wavelengths of 186 nm and below.

The wavelength of light used to activate the photocatalyst is also sufficiently high to photolyze the peroxide bond in the hydrogen peroxide molecule and is also an inhibitor in the production of PHPG for release into the environment. Furthermore, the practice of using the wavelength of light that generates ozone introduces yet another species in the photocatalytic plasma that destroys hydrogen peroxide.

O₃ + H₂O₂ H₂O to 2O₂

In practice, photocatalytic applications focus on generating a plasma, typically containing ozone, for the oxidation of organic pollutants and microorganisms. Such plasmas are mainly effective within the confines of the reactor itself, have limited chemical stability outside the reactor confines by nature, and actively degrade the limited amount of hydrogen peroxide gas they may contain. In addition, since the plasma is primarily effective within the reactor itself, many designs maximize residence time to promote more complete oxidation of organic contaminants and microorganisms as they pass through the reactor. Since hydrogen peroxide has such a high potential to be reduced, maximizing the residence time results in minimized hydrogen peroxide output.

Most applications of photocatalysis also produce environmentally impermissible chemical species. Of which ozone itself, the intentional product of many systems, is the primary concern. In addition, since organic contaminants passing through the reactor are rarely oxidized in one exposure, multiple air exchanges are necessary to achieve complete oxidation to carbon dioxide and water. When incomplete oxidation occurs, the reactor produces a mixture of aldehydes, alcohols, carboxylic acids, ketones, and other partially oxidized organic species. Generally, photocatalytic reactors can actually increase the total concentration of organic pollutants in air by fractionating large organic molecules into a variety of small organic molecules (e.g., formaldehyde).

The process of vaporizing aqueous hydrogen peroxide produces at most the hydrated form of hydrogen peroxide. Furthermore, although photocatalytic systems are capable of producing hydrogen peroxide, they have a number of limitations that severely inhibit the production of PHPG for release into the environment. Applicants have previously disclosed a method and apparatus for producing PHPG in U.S. application No. 12/187,755 (which was disclosed as U.S. patent publication No. 2009/0041617 on 5/1 of 2012 and incorporated herein by reference in its entirety).

The present application provides and includes improved apparatus and methods for generating Purified Hydrogen Peroxide Gas (PHPG).

Summary of the inventionthe present disclosure provides and includes an improved apparatus for producing non-hydrated Purified Hydrogen Peroxide Gas (PHPG), the apparatus comprising a housing, air distribution means providing an air flow, an air permeable substrate structure having a catalyst on a surface thereof, a light source, wherein in operation the air flow passes through the air permeable substrate structure and the apparatus produces PHPG and directs it out of the housing.

The present disclosure provides and includes an apparatus for producing non-hydrated Purified Hydrogen Peroxide Gas (PHPG) when installed in a heating, ventilation and air conditioning (HVAC) system, the apparatus comprising an air permeable substrate structure having a catalyst on a surface thereof and a light source, wherein in operation air flows from the HVAC system through the air permeable substrate structure and the apparatus produces PHPG and directs it away from the air permeable substrate structure and into a heated, ventilated and air conditioned space.

Drawings

Fig. 1A-1C are illustrations of one embodiment of the present disclosure designed to be installed as part of an HVAC system. Notably, the housing and air distribution mechanism are provided by the HVAC system (e.g., ductwork and system fans, respectively).

Fig. 2A-2C are illustrations of an exemplary standalone PHPG generating device according to the present disclosure.

Detailed Description

Before the aspects of the invention are explained in detail, it is to be understood that the invention is not necessarily limited in its application to the details set forth in the following description or exemplified by the examples. The invention is capable of other aspects or of being practiced or carried out in various ways.

The present disclosure provides and includes an apparatus for producing non-hydrated Purified Hydrogen Peroxide Gas (PHPG). In an aspect according to the present disclosure, an apparatus for producing a non-hydrated purified gas comprises a housing, an air distribution mechanism, an ultraviolet light source, a gas permeable substrate structure having a catalyst on a surface thereof, wherein during operation of the apparatus a flow of air passes through the gas permeable substrate structure and directs PHPG produced by the apparatus out of the housing.

In aspects according to the present disclosure, the apparatus produces PHPG and directs PHPG gas out of the enclosure. Without being limited by theory, the production of PHPG gas is rate limiting and depends on the rate at which moisture from the air adsorbs onto the catalyst active sites. Thus, the maximum rate of PHPG gas production is believed to be dependent on humidity and can be calculated assuming the following conditions: 1. a fully hydrated catalyst; 2. the light intensity is sufficient to provide complete activation of the catalyst; 3.100% production without loss due to hydrogen peroxide photolysis or hydrogen peroxide decomposition; and 4. a large excess of oxygen for reduction. Two hydrogen peroxide molecules are produced because two photons produce two hydroxyl radicals, two free electrons and two hydrogen ions, and oxygen molecules are readily available. The ratio of photons used to hydrogen peroxide molecules produced is therefore 1:1 in an extremely ideal case. TiO grade P25₂Present up to 14 x10¹⁴Active site/cm. TiO grade P90₂Present up to 42 x10¹⁴Active site/cm. Thus, a fully hydrated catalyst can use adsorbed water to produce 42 x10, at most, instantly¹⁴A molecule of hydrogen peroxide. Thereafter, the production rate will depend on the rate of adsorption of fresh water onto the catalyst, which is dependent on humidity.

In another aspect, the apparatus produces PHPG at a rate sufficient to establish a steady-state concentration of PHPG of at least 0.005ppm in an enclosed air volume of 10 cubic meters.

In one aspect, the device is at 10 cubic meters (m)³) Produces a concentration of at least 0.005ppm in the volume of air in which 10% of the volume of air is replaced with fresh PHPG-free air per hour.

In aspects according to the present disclosure, hydrogen peroxide gas may be measured in a volume of air. Since there is no readily available device to measure hydrogen peroxide gas at levels below 0.10ppm, a method of measuring the amount of hydrogen peroxide over time or a method using a calibrated pump may be used. In one aspect, the presence of PHPG can be detected over time using a hydrogen peroxide strip commonly used to measure approximate concentrations in aqueous solutions. In one aspect, the hydrogen peroxide test strip can measure up to 1 hour of accumulated PHPG to provide an approximate reading of PHPG concentration accurate to within 0.01 ppm. In certain aspects, at 15 20 second intervals of exposure, a test strip that accumulates 0.5 ppm over a 5 minute process indicates an approximate concentration of 0.033 ppm (e.g., 0.5 ppm divided by 15). In other aspects, Draeger tubes designed to detect hydrogen peroxide concentrations as low as 0.10ppm after drawing 2000 cubic centimeters of air using a calibrated pump provide lower concentration readings accurate to within 0.005ppm when using larger volumes of air for measurements. In certain aspects, a Draeger tube indicating a PHPG measurement at 0.10ppm provides a concentration of 0.05 ppm after 4000 cubic centimeters inhalation. In another aspect, a Draeger tube indicating 0.10ppm measured an approximate PHPG concentration of 0.033 ppm after 6000 cubic centimeters inhalation.

According to the present disclosure, the non-hydrated Purified Hydrogen Peroxide Gas (PHPG) comprises gaseous hydrogen peroxide (H) that is substantially free of hydrated, ozone, plasma species, or organic species₂O₂）。

As used herein, the term "substantially free of ozone" refers to an amount of ozone that is less than about 0.015 ppm ozone. In one aspect, "substantially free of ozone" means that the amount of ozone produced by the device is below or near the detection Level (LOD) using conventional detection devices. Ozone detectors are known in the art and have detection thresholds in ppb using point ionization detection. Suitable ozone detectors are Honeywell Analytics Midas capable of detecting 0.036 to 0.7 ppm ozone^®A gas detector.

As used herein, "substantially free of hydration" means that the hydrogen peroxide gas is at least 99% free of water molecules bound by electrostatic attraction and london forces.

As also used herein, PHPG substantially free of plasma species refers to hydrogen peroxide gas that is at least 99% free of hydroxide ions, hydroxide radicals, hydronium ions (hydronium ions), and hydrogen radicals.

The term "higher" as used herein means at least about 3%, 5%, 7%, 10%, 15%, 20%, 25%, 30%, 50%, 60%, 70%, 80%, 90% or even several times higher.

The term "improve" or "increasing" as used herein means an increase of at least about 2%, at least about 3%, at least about 4%, at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, at least about 50%, at least about 60%, at least about 70%, at least about 80%, at least about 90% or more.

The term "about" as used herein means ± 10%.

The terms "comprising," including, "" having, "and variations thereof mean" including, but not limited to.

The term "consisting of means" including and limited to.

The term "consisting essentially of" means that the composition, method, or structure may include additional ingredients, steps, and/or components, provided that the additional ingredients, steps, and/or components do not materially alter the basic and novel characteristics of the claimed composition, method, or structure.

As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. For example, the term "a compound" or "at least one compound" may include a plurality of compounds, including mixtures thereof.

Whenever a range of numerical values is indicated herein, it is intended to include any recited numerical values (fractional or integer) within the indicated range. The phrases "between a first indicated value and a second indicated value" and "from a first indicated value to a second indicated value" are used interchangeably herein and are intended to include both the first and second indicated values and all fractions and integers therebetween.

The term "method" as used herein refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by practitioners of the agronomic, chemical, pharmacological, biological, biochemical and medical arts.

In an aspect according to the present disclosure, the housing comprises a volume (volume) having at least one opening for air entry and at least one opening for air exit with non-hydrated purified hydrogen peroxide gas. In one aspect, the housing may be made of plastic, metal, wood, or glass. According to some aspects, the housing may be opaque. In other aspects, the housing may be opaque to ultraviolet light and provide transmission of light in the visible spectrum. In one aspect, the housing may further include a reflective surface within the device to reflect light back to the gas permeable substrate structure with the catalyst and thereby increase the production of non-hydrated purified hydrogen peroxide gas. In one aspect, the housing may comprise a material resistant to ultraviolet light degradation. In aspects according to the present disclosure, the housing may be made of a plastic selected from the group consisting of acrylics, polyesters, silicones, polyurethanes, and halogenated plastics. In some aspects, the housing may be made of ceramic or porcelain. In some aspects, the housing may be made of polyethylene, polypropylene, polystyrene, nylon, or polyvinyl chloride.

As used herein, in other aspects, the enclosure may contain a heating, ventilation, and air conditioning (HVAC) system. Referring to fig. 1A to 1C, an apparatus for producing PHPG is an apparatus housed within an existing HVAC system that includes a gas permeable substrate structure 102 having a catalyst on a surface thereof and a light source 104 as recited in paragraphs [00101] to [00109 ]. In other aspects, the device for producing PHPG is a device that is placed in an HVAC system during construction. One aspect of a PHPG production device suitable for incorporation into an HVAC system is illustrated in fig. 1A through 1C. As illustrated, suitable devices may be installed into existing HVAC systems having rectangular ducts according to applicable national and international standards. Suitable HVAC systems and appropriate standards are known in the art, such as the standard developed by Sheet Metal & Air Conditioning controllers' National Association (SMACNA). For example, the American National Standards Institute (ANSI) has recognized SMACNA as a standard-making organization. As provided herein, a device suitable for installation into an HVAC system includes the elements recited for a stand-alone device, but wherein the housing and air distribution system are provided by the HVAC system. A device adapted to be installed into an HVAC system may further include an additional air distribution system (e.g., separate from the air distribution system of the HVAC system as a whole). Devices suitable for installation into an HVAC system may further include one or more additional filters to prevent contamination by dust or chemicals.

In an aspect according to the present disclosure, an apparatus includes an air distribution mechanism to provide an air flow. In some aspects, the air flow is a continuous air flow. In other aspects, the air flow is discontinuous. In aspects according to the present disclosure, the air flow of the apparatus may be a laminar air flow through the air-permeable substrate structure. In other aspects, the air flow may be turbulent flow through the air permeable substrate. In yet another aspect, the air flow may be transitional. In aspects according to the present disclosure, the airflow of the device may have a reynolds number of less than 2300. In another aspect, the air flow of the apparatus may have a reynolds number of 2300 to 4000. In yet another aspect, the air flow of the apparatus may have a reynolds number greater than 4000.

In some aspects, an air distribution mechanism is positioned upstream of the air permeable substrate structure and provides a flow of air through the air permeable substrate. In other aspects, the air distribution mechanism is positioned after the air permeable substrate and air is drawn through the substrate. In certain aspects, the air flow is provided by one or more fans. In certain aspects, the air flow may be provided by a compressed air source. In one aspect, the source of compressed air may be a compressed air tank. In other aspects, the compressed air may be provided by an air compressor and a storage tank. In yet another aspect, the air flow is provided by a climate control system, such as an air conditioner, a furnace, or a heating, ventilation, and air conditioning (HVAC) system.

In aspects according to the present disclosure, the apparatus may provide an air flow having a velocity, direction, and angle of incidence with respect to the air-permeable substrate structure.

The device of the present disclosure has an air flow sufficient to minimize contact time with the photocatalytic surface. More specifically, the device of the present disclosure is designed to minimize contact of the hydrogen peroxide gas generated during the photocatalytic process with the photocatalytic substrate to minimize degradation of hydrogen peroxide by contaminating ozone, hydroxide ions, hydroxyl radicals, hydronium ions, and hydrogen radicals. This minimization of ozone generation and contact is different from "air purification" filters and devices that use similar photocatalytic principles. Unlike the devices of the present disclosure, the air purifier and filter are designed to maximize air contact with the catalytic surface and the photocatalytic plasma. Still further, previous filters and purifiers were designed to operate within an enclosed volume and were designed not to exhaust PHPG but rather "clean" air that has destroyed or reduced Volatile Organic Compounds (VOCs), bacteria, microorganisms, spores, viruses, and other undesirable contaminants. Similarly, previous filters and purifiers have been directed to the generation of ozone and/or hydroxyl radicals, each of which is undesirable in the devices of the present disclosure.

The apparatus of the present disclosure includes and provides an air distribution mechanism capable of providing an air flow having a velocity of about 5 nanometers per second (nm/s) to 10,000 nm/s as measured at a surface of an air permeable substrate structure. In certain aspects, the flow rate is from 5nm/s to 7,500 nm/s. In certain aspects, the flow rate is 5nm/s to 5,000 nm/s. In certain aspects, the flow rate is from 5nm/s to 2,500 nm/s. In certain aspects, the flow rate is 5nm/s to 5,000 nm/s. In certain aspects, the flow rate is from 5nm/s to 1,000 nm/s. In other aspects, the air flow rate at the air-permeable substrate structure is from 5 to 15 nm/s. In another aspect, the air flow rate is 15nm/s to 30 nm/s. In one aspect, the air flow rate is 30 nm/s to 50 nm/s. In one aspect, the air flow rate is 50 nm/s to 75 nm/s. In one aspect, the air flow rate is 75 nm/s to 100 nm/s. In one aspect, the air flow rate is from 100 nm/s to 250 nm/s. In one aspect, the air flow rate is 250 nm/s to 500 nm/s. In one aspect, the air flow rate is from 500 nm/s to 750 nm/s. In one aspect, the air flow rate is 750 nm/s to 1000 nm/s. In one aspect, the air flow rate is 1000 nm/s to 2,500 nm/s. In one aspect, the air flow rate is 2,500 nm/s to 5,000 nm/s. In one aspect, the air flow rate is 5,000 nm/s to 7,500 nm/s. In one aspect, the air flow rate is 7,500 nm/s to 10,000 nm/s. As provided herein, the maximum air flow through the air permeable structure is limited by the reaction of hydroxyl radicals to hydrogen peroxide and the production rate of PHPG droplets. Without being limited by theory, it is believed that the hydroxyl radicals are maintained in a sufficiently dilute equilibrium that facilitates their combination to form hydrogen peroxide with minimal decomposition to water and oxygen. The maximum flow (flow) limit depends on the air permeable structure, catalyst, relative humidity and other variables and one of ordinary skill in the art can readily adjust the air flow to maximize PHPG production. In certain aspects, devices suitable for use in HVAC systems are designed to handle air flows up to 40,000 cubic feet per minute (CFM).

The present disclosure provides and includes an air flow rate through an air permeable substrate structure of greater than 100 CFM. In one aspect, an average 145 CFM airflow is provided for a PHPG generating device for an HVAC system. For a stand-alone PHPG generating device, the air distribution mechanism provides an average of 115 CFM through the air permeable substrate structure.

The present disclosure also includes and provides a device having an air flow rate sufficient to provide a residence time on the catalyst surface of less than 1 second. One of ordinary skill in the art will appreciate that the time available at the catalyst surface is influenced by parameters such as air velocity, angle of incidence, and substrate thickness. In aspects according to the present disclosure, the apparatus provides a residence time on the catalyst surface of the gas permeable substrate of less than 2 seconds. In one aspect, the residence time is less than 1 second. In some aspects, the dwell time is less than 500 milliseconds. In another aspect, the dwell time is less than 250 milliseconds. In yet another aspect, the residence time is from 1 to 500 milliseconds.

In aspects, the direction of air flow at the air-permeable structure may be provided at an angle (angle of incidence) with respect to the air-permeable structure. Unlike the present disclosure, the PHPG production apparatus disclosed in U.S. patent nos. 8,168,122, 8,684,329, and 9,034,255 provides a diffusion device for the production of non-hydrated purified peroxide gas (PGPG) from humid ambient air with air flow perpendicular to the thin air permeable substrate structure. Here, applicants show that the production of PHPG can be achieved using an air stream incident at an angle of at least 14 ° to the air permeable substrate. Without being limited by theory, it is believed that the allowable angle of incidence is related to the thickness of the air permeable substrate structure and the velocity of the air flow. As the thickness of the substrate structure decreases, the angle of incidence may also decrease, starting at 90 ° (the angle of the air flow to the substrate), which provides optimal conditions for PHPG production by maintaining a short residence time of hydrogen peroxide on the substrate surface. Similarly, for a given substrate thickness, as the velocity of the air flow increases, the angle of incidence may decrease, however angles below 14 ° do not result in the generation of detectable levels of PHPG. Without being limited by theory, PHPG production rates are greatest at 90 ° incident angle and are substantially undetectable when the incident angle of the air stream is about 14 ° or less. The yield of PHPG steadily increased at approximately 14 ℃ to 68 ℃. Surprisingly, at incident angles as low as 68 ℃, suitable levels of PHPG were produced, and in agreement with previous reports, the best yield occurred when the air flow was vertical. Accordingly, prior art devices having catalytic surfaces parallel to the air flow do not produce PHPG even if the incident light is normal. Thus, prior art devices designed to generate ozone, peroxide, and other reactive species within the reactor do not produce PHPG and do not conduct PHPG out of the reactor.

In certain aspects, the air flow may be provided at a 90 ° angle of incidence relative to the air permeable substrate structure (e.g., perpendicular to the air permeable substrate). For a given air flow and substrate thickness, the residence time of the non-hydrated purified hydrogen peroxide gas is minimal in the apparatus with a 90 ° angle of incidence. In an aspect according to the present disclosure, the minimum angle of incidence is 14 °. In other aspects, the angle of incidence of the air flow with respect to the air-permeable structure is at least 45 ° or greater. In another aspect, the angle of incidence is greater than 50 °. In yet another aspect, the angle of incidence is greater than 60 °. In yet another aspect, the angle of incidence is greater than 70 °. In another aspect, the angle of incidence is greater than 75 °. In one aspect, the angle of incidence may be greater than 80 °. In yet another aspect, the angle of incidence may be greater than 85 °. In yet another aspect, the angle of incidence may be greater than 89 °. In aspects according to the present disclosure, the incident angle of the air flow may be 68 ° to 90 ° with respect to the substrate structure. In other aspects, the incident angle of the air flow may be 75 ° to 90 ° with respect to the substrate structure. In other aspects, the incident angle of the air flow may be 85 ° to 90 ° relative to the substrate structure.

In aspects according to the present disclosure, the air flow through the air permeable substrate structure is humid air. In certain aspects, the humid air is ambient humid air. In other aspects, the humidity of the air flowing through the air permeable substrate is equal to or greater than 20% RH. In other aspects, the humidity of the air flowing through the air permeable substrate is equal to or greater than 30%. In some aspects, the relative humidity is 35% to 40%. In other aspects, the humidity of the ambient air can be about 20% to about 99% RH. In other aspects, the humidity of the ambient air can be about 20% to about 99% RH. In certain aspects, the humidity of the air stream is less than 80%. In one aspect, the humidity is 20% to 80%. In still other aspects, the relative humidity is 30% to 60%. In another aspect, the humidity is 35% to 40%. In some aspects, the humidity of the air flowing through the air permeable substrate structure is from 56% to 59%. In aspects according to the present disclosure, the relative humidity is 20% to 80%.

In aspects according to the present disclosure, the flow of air through the air-permeable substrate structure may be supplemented by humidification. In certain aspects, ambient air is supplemented by a humidifier to provide an air stream having a humidity of at least 20%. In certain aspects, the relative humidity of the air flowing through the permeable substrate structure is maintained between 20% and 80%. In another aspect, the air may be humidified to 30% or greater relative humidity. In some aspects, the relative humidity of the humidified air stream is from 35% to 40%. In other aspects, the humidity of the humidified air can be about 20% to about 99% or about 30% to 99% RH. In one aspect, the relative humidity after humidification is less than 80%. In one aspect, the relative humidity after humidification is from 20% to 80%. In still other aspects, the relative humidity after humidification is from 30% to 60%. In another aspect, the relative humidity after humidification is from 35% to 40%. In some aspects, the relative humidity of the air flowing through the air permeable substrate structure after humidification is from 56% to 59%.

In aspects according to the present disclosure, a device may provide an air flow that circulates air within a space. In other aspects, the device may provide, in whole or in part, an air stream comprising fresh air. In certain aspects, the device includes and provides a source of fresh air from the outside or from a separate flow of filtered air. In aspects according to the present disclosure, the apparatus may be included in an air conditioning and ventilation system that circulates air in a room or building. In some aspects, the circulating indoor or building air may be supplemented with fresh outdoor air.

The device of the present disclosure includes a gas permeable substrate structure having a catalyst on a surface configured to produce a non-hydrated purified hydrogen peroxide gas when exposed to a light source and provided with a flow of air. The substrate structure may vary in thickness, air permeability, and surface catalyst. In certain aspects, the substrate structure may be thicker or thinner depending on the velocity of the air flow, the angle of incidence of the air flow, the light intensity, and the type of catalyst. The thickness, air flow angle, and other parameters are selected to provide a substrate surface morphology that serves to minimize the residence time of hydrogen peroxide molecules on the surface of the gas permeable substrate structure. Without being limited by theory, it is believed that hydrogen peroxide gas generated on the surface of the substrate is released from the surface and thereby prevented from being reduced back into water by the substrate or hydroxide.

In aspects according to the present disclosure, the total thickness of the air-permeable substrate structure having the catalyst on its surface is from about 5 nanometers (nm) to about 750 nm. In certain aspects, the air permeable substrate structure has a maximum thickness of 650 nanometers. In one aspect, the air permeable substrate structure has a thickness of 100 to 200 nanometers. In one aspect, the air permeable substrate structure has a thickness of 145 to 150 nanometers. In one aspect, the air permeable substrate structure has a thickness of 5 nanometers to 15 nanometers. In another aspect, the air permeable substrate structure has a thickness of 15 nanometers to 30 nanometers. In one aspect, the air permeable substrate structure has a thickness of 20 nanometers to 40 nanometers. In one aspect, the thickness of the air permeable substrate structure is about 30 nanometers. In yet another aspect, the air permeable substrate structure has a thickness of 30 nanometers to 50 nanometers. In yet another aspect, the air permeable substrate structure has a thickness of 50 nanometers to 75 nanometers. In one aspect, the air permeable substrate structure has a thickness of 75 nanometers to 100 nanometers. In yet another aspect, the air permeable substrate structure has a thickness of 100 nm to 250 nm. In yet another aspect, the air permeable substrate structure has a thickness of 250 nanometers to 500 nanometers. In certain aspects, the air permeable substrate structure has a thickness of 500 nanometers to 750 nanometers. In aspects according to the present disclosure, the gas permeable substrate structure having the catalyst on a surface thereof has a thickness of about 5 to 100 nanometers. In one aspect, the gas permeable substrate structure having the catalyst on its surface has a thickness of about 15 to 100 nanometers. In one aspect, the gas permeable substrate structure having the catalyst on its surface has a thickness of about 20 to 100 nanometers. In one aspect, the gas permeable substrate structure having the catalyst on its surface has a thickness of about 20 to 75 nanometers. In one aspect, the gas permeable substrate structure having the catalyst on its surface has a thickness of about 20 to 50 nanometers.

In certain aspects according to the present disclosure, the total thickness of the air permeable substrate structure having the catalyst on its surface is from about 750 nanometers (nm) to about 1000 nm. In one aspect, the air permeable substrate structure has a thickness of 1000 to 2500 nanometers. In another aspect, the air permeable substrate structure has a thickness of 2500 nanometers to 5000 nanometers. In one aspect, the air permeable substrate structure has a thickness of 5000 nanometers to 7500 nanometers. In yet another aspect, the air permeable substrate structure has a thickness of 7500 nanometers to 10000 nanometers.

Also provided and included in the present disclosure are devices having a breathable substrate structure configured as a mesh. As used herein, "mesh" refers to a spatial network in a net or network, including a network of ropes, wires, or filaments. In some aspects, the mesh may be a woven cloth or fabric. In some aspects, the mesh may be braided stainless steel. In certain aspects, the mesh may be woven stainless steel formed into a honeycomb. In other aspects, the mesh may be a nonwoven or fabric. In certain aspects, the mesh may be prepared from a solid sheet by mechanical, thermal or chemical introduction of holes or perforations. In one aspect, the mesh may be made from a film.

In developing the devices of the present disclosure, it was observed that a breathable substrate structure required a mesh having at least 20% open area (open area) to generate an effective amount of PHPG. Similarly, when the open area of the mesh is greater than 60%, PHPG production is substantially eliminated. Accordingly, the present disclosure provides and includes air permeable substrate structures having a mesh with an open area of 20% to 60% and a maximum thickness of up to 750 nanometers. Suitable thicknesses for the breathable substrate are provided above in paragraphs [0061] and [0062 ]. Also included are air permeable substrate structures having a mesh with an open area of about 40%. In one aspect, the mesh is about 200 microns and the wire thickness is about 152 microns.

Additional tests have shown that nonwoven fabrics are not suitable for preparing breathable substrates coated with catalyst. Without being limited by theory, it is believed that the failure to identify a suitable nonwoven material is due to the irregular or inadequate network of nonwoven materials. However, it is believed that suitable nonwoven materials can be prepared. Accordingly, the present disclosure includes and provides nonwoven, air permeable substrate structures having a mesh size of 20 to 60% and a thickness of less than 750 nanometers that are useful in the preparation of PHPG generating devices.

In aspects according to the present disclosure, the mesh is greater than 20 strands/cm. In certain aspects, the open area of the mesh is less than about 120 strands/cm. In one aspect, the mesh openings are about 200 microns (μm), which corresponds to about 41% open area at a line thickness of about 150 microns. In certain aspects, the mesh comprises at least about 20% open area and a line thickness of about 48 microns. In certain aspects, the mesh has a pore size of 25 to 220 microns and has an open pore area of 20 to 40%. In other aspects, the mesh has a pore size of 25 to 220 microns and a line thickness of 48 to 175 microns.

In aspects according to the present disclosure, a grid having a regular repeating pattern of spaces in the mesh or network may be prepared. In other aspects, the grid of the present disclosure may have a spatially irregular or non-repeating pattern. In yet another aspect, the lattice can be a random arrangement of open spaces. In another aspect, the mesh may have a honeycomb appearance. In aspects according to the present disclosure, the open spaces within the mesh are circular, triangular, square, polygonal, polyhedral, elliptical, or spherical.

The breathable substrate structures of the present disclosure can be made from a number of suitable materials. In certain aspects, the gas permeable substrate structure may comprise a catalyst. In other aspects, the air permeable substrate structure may comprise a catalyst and a promoter. In still other aspects, the air permeable substrate structure may comprise a catalyst, a promoter, and an additive. In certain aspects, the gas permeable substrate structure may be prepared as a ceramic. In still other aspects, the air permeable substrate structure consists of only a catalyst or a catalyst/co-catalyst combination.

The present disclosure also provides a coated breathable substrate. In some aspects, the air permeable substrate structure may comprise a material coated with one or more catalysts. In other aspects, the air permeable substrate structure may comprise a material coated with a catalyst and one or more promoters. In yet another aspect, the air permeable substrate structure may comprise a material coated with a mixture of a catalyst, a promoter, and an additive.

Methods for coating breathable substrates are known in the art. In certain aspects, a gas permeable substrate is coated with crystalline titanium dioxide powder in one or more applications and sintered in a furnace. The coating of the present disclosure may be applied to the mesh by various methods including, but not limited to, gel-sol methods, coating (painting), dipping, and powder coating. In other aspects, the catalysts, co-catalysts, and additives of the present disclosure may be applied to the mesh by roll coating, tape casting, ultrasonic spraying, and web-based coating. The method of applying the catalyst, promoter and additives as provided herein is suitable if it provides and includes a grid that holds an underlying air permeable substrate as cited above.

According to the present disclosure, a breathable substrate structure comprises a mesh having an open area percentage of 20% to 60% after coating. In another aspect, the mesh may have an open area of 20% to 30%. In one aspect, the mesh may have an open area of 30% to 40%. In yet another aspect, the mesh may have an open area of 40% to 50%. In yet another aspect, the mesh may have an open area of 50% to 60%. In certain aspects, the open area percentage of the mesh may be 36% to 38%. In one aspect, the open area percentage is about 37%.

The present disclosure provides and includes an air permeable substrate structure having a thickness of 5 to 750 nanometers and having an open area of the mesh of 10 to 60 percent. In one aspect, the substrate structure may have a thickness selected from the group consisting of 5nm to 15nm, 15nm to 30 nm, 20 nm to 40 nm, 30 nm to 50 nm, 50 nm to 75 nm, 75 nm to 100 nm, 100 nm to 250 nm, 250 nm to 500 nm, and 500 nm to 750 nm and have an open area of a mesh between 10% and 20%. In one aspect, the substrate structure may have a thickness selected from the group consisting of 5nm to 15nm, 15nm to 30 nm, 20 nm to 40 nm, 30 nm to 50 nm, 50 nm to 75 nm, 75 nm to 100 nm, 100 nm to 250 nm, 250 nm to 500 nm, and 500 nm to 750 nm and have an open area of mesh between 20% and 30%. In one aspect, the substrate structure may have a thickness selected from the group consisting of 5nm to 15nm, 15nm to 30 nm, 20 nm to 40 nm, 30 nm to 50 nm, 50 nm to 75 nm, 75 nm to 100 nm, 100 nm to 250 nm, 250 nm to 500 nm, and 500 nm to 750 nm thick and have an open area of mesh between 30% and 40%. In one aspect, the substrate structure may have a thickness selected from the group consisting of 5nm to 15nm, 15nm to 30 nm, 20 to 40 nm, 30 nm to 50 nm, 50 nm to 75 nm, 75 nm to 100 nm, 100 nm to 250 nm, 250 nm to 500 nm, and 500 nm to 750 nm thick and have an open area of mesh between 40% and 50%. In one aspect, the substrate structure may have a thickness selected from the group consisting of 5nm to 15nm, 15nm to 30 nm, 20 to 40 nm, 30 nm to 50 nm, 50 nm to 75 nm, 75 nm to 100 nm, 100 nm to 250 nm, 250 nm to 500 nm, and 500 nm to 750 nm thick and have an open area of mesh between 50% and 60%. In one aspect, the substrate structure may have a thickness selected from the group consisting of 5nm to 15nm, 15nm to 30 nm, 20 nm to 40 nm, 30 nm to 50 nm, 50 nm to 75 nm, 75 nm to 100 nm, 100 nm to 250 nm, 250 nm to 500 nm, and 500 nm to 750 nm thick and have an open area of mesh between 36% and 38%.

In other aspects, the air permeable substrate structure has a thickness of 15nm to 250 nm and has an open area of the mesh of 20% to 50%. In another aspect, the air permeable substrate structure has a thickness of 15nm to 100 nm and has an open area of the mesh of 20% to 50%. In another aspect, the air permeable substrate structure has a thickness of 20 to 80 nanometers and has an open area of the mesh of 20 to 50%. In another aspect, the air permeable substrate structure has a thickness of 20 to 50 nanometers and has an open area of the mesh of 20 to 50%. In another aspect, the air permeable substrate structure has a thickness of 20 to 40 nanometers and has an open area of the mesh of 20 to 50%.

In other aspects, the air permeable substrate structure has a thickness of 15nm to 250 nm and has an open area of the mesh of 30% to 50%. In another aspect, the air permeable substrate structure has a thickness of 15nm to 100 nm and has an open area of the mesh of 30% to 50%. In another aspect, the air permeable substrate structure has a thickness of 20 to 80 nanometers and has an open area of the mesh of 30 to 50%. In another aspect, the air permeable substrate structure has a thickness of 30 to 50 nanometers and has an open area of the mesh of 30 to 50%. In another aspect, the air permeable substrate structure has a thickness of 20 to 40 nanometers and has an open area of the mesh of 30 to 50%.

In other aspects, the air permeable substrate structure has a thickness of 20 nm to 40 nm and has an open area of the mesh of 10% to 60%. In another aspect, the air permeable substrate structure has a thickness of 20 to 40 nanometers and has an open area of the mesh of 20 to 50%. In another aspect, the air permeable substrate structure has a thickness of 20 to 40 nanometers and has an open area of the mesh of 30 to 40%. In another aspect, the air permeable substrate structure has a thickness of 20 to 40 nanometers and has an open area of the mesh of 36 to 38%. In another aspect, the air permeable substrate structure has a thickness of 20 nm to 40 nm and has an open area of the mesh of about 37%.

Breathable substrates suitable for coating with the catalyst mixtures of the present disclosure are known in the art. In certain aspects, the gas permeable substrate comprises a solid sheet coated with a catalyst or catalyst-containing mixture and then rendered gas permeable by the introduction of voids or perforations as provided above. In other aspects, the gas permeable substrate comprises a solid sheet that has been perforated and subsequently coated with a catalyst or catalyst mixture.

Breathable substrates suitable for coating with the catalyst mixtures according to the present disclosure include meshes, such as woven or woven fabrics or non-woven or woven fabrics. As provided herein, coating a suitable mesh with a catalyst mixture requires that the mesh not be clogged and that the mesh maintain an open area of 20% to 60% as provided above.

The breathable substrates of the present disclosure may be made from polymers, carbon fibers, glass fibers, natural fibers, metal filaments, and other materials that may be made into a web. The mesh may be a woven mesh made from monofilament synthetic or natural fibers or yarns. In other aspects, the woven mesh may be made from multifilament synthetic fibers or yarns. The woven mesh of the present disclosure may be described by a thread count (thread count) and have a thread diameter. Woven meshes comprise warp threads running longitudinally in the woven mesh or fabric and filling threads running transversely across the width of the fabric at right angles to the warp threads. In a woven mesh comprising monofilaments, there are equal diameter wires and equal wire counts in the warp and weft and square meshes (or meshes). The monofilament woven mesh may have different numbers of thread counts in the warp and weft directions to create a rectangular mesh. Woven meshes are available in a wide variety of thread counts.

Woven single wire mesh lattices suitable for use in the devices of the present disclosure include a mesh having a nominal pore size (e.g., mesh opening) of 50 microns to 1200 microns. In one aspect, a woven single wire mesh suitable for coating as an air permeable substrate has a mesh opening of 100 to 300 microns. In another aspect, the breathable substrate is a woven monofilament mesh having openings of 150 to 250 microns. In yet another aspect, the breathable substrate is a woven monofilament mesh having a mesh opening of about 200 microns. In one aspect, the woven single wire mesh has openings of 175 to 225 microns and a wire thickness of 125 to 175 microns. In yet another aspect, the woven single wire mesh has openings of about 200 microns and a wire thickness of about 152 microns.

In aspects according to the present disclosure, the mesh may be an extruded mesh (also referred to as an "extruded mesh"). In one aspect, the extruded mesh may be a bi-planar extruded mesh. In another aspect, the extruded mesh may be a single planar mesh. The extruded mesh may comprise a mesh having various pore sizes (pore sizes), weights, and thicknesses. Extruded meshes may be made from polypropylene (PP), Polyethylene (PE), High Density Polyethylene (HDPE), Medium Density Polyethylene (MDPE), Low Density Polyethylene (LDPE), polypropylene/polyethylene (PP/PE) blends, crosslinked Polyethylene (PEX), Ultra High Molecular Weight Polyethylene (UHMWPE).

In one aspect, a mesh suitable for coating according to the present disclosure is a fiberglass mesh or cloth. In some aspects, the fiberglass mesh is Fiberglass Reinforced Plastic (FRP). In some aspects, the fiberglass mesh is a woven mesh. Suitable woven glass fiber meshes include glass fiber cloth, glass chopped strand mats, and scrims (wovenrovings). In some aspects, the fiberglass cloth is a combination of roving cloth and chopped strands. In another aspect, the fiberglass cloth is S-2 GLASS^TM. In some aspects, a plain weave, multiple satin weave (long s) is usedA loft satin weave), a unidirectional weave or a twill weave. In one aspect, the fiberglass cloth comprises E-glass. In another aspect, the fiberglass cloth comprises C-glass. In yet another aspect, the fiberglass cloth comprises E-glass and C-glass. In some aspects, a fiberglass mesh or cloth is combined with a resin to reinforce the fiberglass material. In one aspect, the resin is a polyester. In another aspect, the resin is an epoxy resin.

In one aspect, a mesh suitable for coating according to the present disclosure is a polymer. In one aspect, the mesh may be nylon, polybutylene terephthalate (PBT), polyester, polyethylene, polypropylene, Polytetrafluoroethylene (PTFE), polypropylene/polyethylene (PP/PE) blends, or synthetic yarns or fibers.

In aspects according to the present disclosure, the mesh may be made from natural fibers, including cotton and wool. In some aspects, the natural fiber is seed fiber, leaf fiber, bast fiber, skin fiber, fruit fiber, or straw fiber. In other aspects, the natural fiber is hemp, sisal, jute, kenaf, or bamboo. In one aspect, the mesh may be prepared from silk.

The mesh according to the present disclosure may be a metal mesh or a ceramic mesh. Suitable metal grids include electroformed screens. Electroformed screens suitable for use in preparing catalyst coated breathable substrates according to the present disclosure may be obtained, for example, from Industrial nettings (MN). The electroformed screen can have a pore size of 8 microns to 5000 microns or more. In certain aspects, the electroformed screen is 36% to 98% open. In some aspects, the electroformed screen is 36% to 98% open and has a thickness of about 20 nm to 75 nm.

The apparatus of the present disclosure provides and includes a catalyst on a surface of the gas permeable substrate structure. In certain aspects, the catalyst can be a catalyst mixture comprising one or more catalysts. In other aspects, the catalyst mixture can comprise one or more catalysts and one or more co-catalysts. In another aspect, the catalyst mixture may comprise one or more catalysts and one or more additives. In yet another aspect, the catalyst mixture may comprise one or more catalysts, one or more promoters, and one or more additives. The catalyst mixture may further comprise solubilizers, binders, viscosity modifiers, isotonicity agents, pH modifiers, solvents, dyes, gelling agents, thickeners, buffers, and combinations thereof.

One of ordinary skill in the art will appreciate that the choice of catalyst determines the type of photocatalysis that occurs upon irradiation with a light source and further determines the wavelength and intensity of light suitable for generating the non-hydrated purified hydrogen peroxide gas. As discussed above, hydroxyl radicals produced by photocatalysis must be removed from the catalytic surface before they undergo reduction by free electrons on the catalyst or by other reactive species produced by photocatalysis. This forces them to combine to form hydrogen peroxide upon passing over the catalyst. One of ordinary skill in the art will appreciate that the residence time of the non-hydrated purified hydrogen peroxide gas on the gas permeable substrate depends on the substrate thickness, the angle of incidence of the air flow, and the air flow velocity.

In aspects according to the present disclosure, the catalyst on the surface of the air-permeable substrate structure is a metal, a metal oxide, or a mixture thereof. Ceramic catalysts are also provided and included in the present disclosure. Catalysts of the present disclosure include, but are not limited to, titanium dioxide, copper oxide, zinc oxide, iron oxide, or mixtures thereof. Suitable catalysts are provided, for example, in table 2. In some aspects, the catalyst is anatase or rutile form of titanium dioxide. In certain aspects, the titanium dioxide is in the anatase form. In some aspects, the catalyst is rutile form of titanium dioxide. In other aspects, the titanium dioxide catalyst is a mixture of anatase and rutile. Anatase absorbs photons having a wavelength of less than 380 nanometers, while rutile absorbs photons having a wavelength of less than 405 nanometers. Further provided on the surface comprises tungsten trioxide (WO)₃) (which enables the use of a complete spectrum with an energy of at least 2.85 eV). This extends the light source beyond TiO alone₂The visible light range of the activity range of (1).Without being limited by theory, WO₃Providing TiO₂New energy levels are not supported and are capable of adsorbing visible light of sufficient energy to oxidize water to hydroxyl radicals. Accordingly, the present disclosure further provides and includes a light source that provides a wavelength in the visible range when paired with a suitable catalyst substrate.

TABLE 2 photocatalyst having appropriate band gap energy

Photocatalyst and process for producing the same	Band gap energy (Electron volts (eV))
		Si	1.1
WSe2	1.2
		CdS	2.4
WO3	2.4-2.8
		V2O5	2.7
SiC	3.0
		TiO2(rutile)	3.02
Fe2O3	3.1
		TiO2Anatase ore	3.2
ZnO	3.2
		SRTiO3	3.2
SnO2	3.5
		ZnS	3.6

In certain aspects, the catalyst may be tungsten oxide or a mixture of tungsten oxide and another metal or metal oxide catalyst. In some aspects, the catalyst is selected from tungsten (III) oxide, tungsten (IV) oxide (WO)₂) Tungsten (VI) oxide (WO)₃) And tungsten pentoxide. In one aspect, the tungsten oxide is tungsten dioxide (WO)₂). In another aspect, the catalyst may be tungsten trioxide in combination with a cesium promoter (WO)₃) A catalyst. (see "Development of a High-performance Photocalalyst that is Surface-processed with centre", available on the Internet at www.aist.go.jp/air _ e/latest _ research/2010/20100517/20100517. html).

The catalyst of the present disclosure may further comprise one or more promoters. In certain aspects, the promoter provides light absorption capability in the visible spectrum (e.g., wavelengths of about 390 nm to 700 nm). Suitable catalysts and methods of preparing catalysts to provide catalysts suitable for use in devices having a light source that emits in the visible spectrum are known in the art. See, e.g., Tukenmez,"Tungsten Oxide Nanopowders and Its Photocatalytically Activity unit Visible Light Irradation", Thesis, Department of molecular biology, Umea University, Sweden, (2013), available on the Internet at www.diva-port.org/smash/get/diva 2:643926/FULLTEXT01. pdf; kim et al, "Photocaltic Activity of TiO₂Films predicted under differential Conditions The Gas-Phase photonic Degradation Reaction of Trichloroethylene, Journal of catalysis 194(2) 484-486 (2000); blake et al, "Application of the Photocosmetic chemistry of Titanium Dioxide to dispensing and the filling of cancer cells", Separation and Purification Methods 28(1) 1-50 (1999); sugihara et al, "Development of a visual Light Responsive photography Using tubular oxide Lighting", National Institute of Advanced Industrial Science and Technology (AIST) (2008). Promoters of the present disclosure include, but are not limited to, platinum, gold, silver, copper, nickel, cesium, or palladium. In some aspects, the promoter is a noble metal selected from the group consisting of gold, platinum, silver, rhodium, ruthenium, palladium, osmium, and iridium. In one aspect, the promoter is gold. In another aspect, the promoter is silver. In yet another aspect, the promoter is platinum. In another aspect, the promoter is an extruded ceramic. In certain aspects, the promoter is zirconium dioxide (ZrO)₂). In some aspects, the promoter is an extruded titanium Dioxide ceramic (see Shon et al, "Visible Light responsive titanium Dioxide (TiO)₂) -a review ", available at ep.

The disclosure also includes compositions comprising metallic palladium, copper and WO₃Supported catalysts that provide a photocatalytic reaction occurring into the 460 nm visible spectrum and provide a 7-fold increase in activity on the catalyst. In other aspects, the catalyst comprises WO₃And TiO₂The blend of (a), which increases the photocatalytic reaction at a wavelength of 410 nm by up to 60 times. In yet another aspect, WO₃And TiO₂The blend of (a) allows the use of a light source comprising an XE lamp at 400 nm. In other aspects, nitrogen is usedIons or WO₃The catalyst is incorporated to provide a photocatalytic reaction in the visible spectrum. In other aspects, the coating is formed from a composition comprising TiO₂And SiO₂The photocatalyst of the blend of (a) provides absorption in the visible spectrum to generate a band gap of 3.3 eV.

TABLE 3 cocatalyst and absorption wavelength

Co-catalyst	Wavelength of light
		Gold (AU)	It can be seen that
Pt
		Ag
Titanium dioxide ceramics	It can be seen that

The co-catalyst of the present disclosure can be provided in various amounts relative to the catalyst. Generally, the cocatalyst may be provided at levels up to about 5%. In certain aspects, the amount of cocatalyst is 5% or less, although in certain aspects a combined amount of cocatalyst mixture of up to 10% may be used. In certain aspects, up to 1.0% of the total mass of the catalyst can be a promoter of the type described above. In some aspects, the total amount of cocatalyst is up to 0.05%. In still other aspects, the cocatalyst is provided at 0.005 to 0.05%. In some aspects, the cocatalyst is provided at 0.01 to 0.05%. In another aspect, the cocatalyst is provided at 0.01% to 0.02%. In certain aspects, the promoter is provided at less than 0.05% of the total mass of the catalyst.

The catalyst of the present disclosure may further comprise one or more additives. In one aspect, the additive may be a hygroscopic additive. Without being limited by theory, it is believed that the presence of the hygroscopic additive increases the local water concentration on the photocatalytic surface and thereby enables non-hydrated purified hydrogen peroxide gas production at lower humidity levels and improves PGPG production efficiency at higher humidity levels. As provided herein, the catalyst coating with the moisture absorbent extends the efficiency of the PHPG generating device and extends the relative humidity range in which the PHPG generating device is effective to operate and can produce PHPG at a rate sufficient to establish a steady state concentration of PHPG of at least 0.005ppm in an enclosed volume of air of 10 cubic meters. In certain aspects, the relative humidity can be as low as 1%. In one aspect, the humidity of the ambient air is preferably above about 1% Relative Humidity (RH). In certain aspects, the relative humidity can be 1 to 99%. In other aspects, the humidity of the air flowing through the air permeable substrate is from 1% to 20% RH. In other aspects, the humidity of the air flowing through the air permeable substrate is equal to or greater than 5%. In other aspects, the humidity of the ambient air can be about 10% to about 99% RH. In other aspects, the humidity of the ambient air can be about 10% to about 99% RH. In certain aspects, the humidity of the air stream is less than 80%. In one aspect, the humidity is 10% to 80%. In still other aspects, the relative humidity is 30% to 60%. In another aspect, the humidity is 35% to 40%. In some aspects, the humidity of the air flowing through the air permeable substrate structure is from 56% to 59%.

In aspects according to the present disclosure, the hygroscopic additive may be selected from the group consisting of sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, magnesium bicarbonate, sodium hydroxide, potassium hydroxide, magnesium hydroxide, zinc chloride, calcium chloride, magnesium chloride, sodium phosphate, potassium phosphate, magnesium phosphate, carnallite (KMgCl)₃·6(H₂O)), ferric ammonium citrate, nylon, Acrylonitrile Butadiene Styrene (ABS), polycarbonate, cellulose, poly (methyl methacrylate)) And combinations thereof.

In aspects according to the present disclosure, the hygroscopic additive may be a salt. In certain aspects, the hygroscopic additive may be a bicarbonate salt. In one aspect, the hygroscopic additive is sodium bicarbonate. In one aspect, the hygroscopic additive is potassium bicarbonate. In one aspect, the hygroscopic additive is magnesium bicarbonate. In other aspects, the hygroscopic additive can be a carbonate. In one aspect, the hygroscopic carbonate is sodium carbonate, potassium carbonate, or magnesium carbonate. In some aspects, the hygroscopic additive may be a hydroxide. In certain aspects, the hygroscopic additive may be sodium hydroxide, potassium hydroxide, or magnesium hydroxide. In some aspects, the hygroscopic additive may be a chloride. In certain aspects, the hygroscopic additive can be zinc chloride, calcium chloride, or magnesium chloride. In still other aspects, the hygroscopic additive may be a phosphate. In certain aspects, the hygroscopic phosphate can be a sodium, potassium, or magnesium phosphate. It is to be understood that one or more hygroscopic compounds may be combined.

In general, the additives may be provided at levels up to about 5%. In certain aspects, the amount of additive is 5% or less, although in certain aspects a combined amount of up to 10% of the additive mixture may be used. In certain aspects, up to 1.0% of the total mass of the catalyst may be an additive of the type described above. In some aspects, the total amount of additives is up to 0.05%. In still other aspects, the additive is provided at 0.005 to 0.05%. In some aspects, the additive is provided at 0.01 to 0.05%. In another aspect, the additive is provided at 0.01% to 0.02%. In certain aspects, the additive is provided at less than 0.05% of the total mass of the catalyst.

The present disclosure also provides and includes a catalyst surface having a pH of 6.0 or greater. Without being limited by theory, it is believed that the higher pH provides an improved source of oxidizable hydroxide ions in the photocatalytic process, thereby increasing the yield of non-hydrated purified hydrogen peroxide gas. In one aspect, the pH of the catalyst surface is greater than pH 7.0. In another aspect, the surface has a pH of 7.0 to 9.0. In one aspect, the pH of the catalyst surface is from 7.0 to 8.5. In one aspect, the pH of the catalyst surface is from 7.0 to 8.0. In one aspect, the pH of the catalyst surface is from 7.0 to 7.5. In another aspect, the surface has a pH of 7.5 to 9.0. In one aspect, the pH of the catalyst surface is from 7.5 to 8.5. In one aspect, the pH of the catalyst surface is from 7.5 to 8.0. In another aspect, the surface has a pH of 8.0 to 9.0. In one aspect, the pH of the catalyst surface is from 8.0 to 8.5. In certain aspects, the surface has a pH of at least 7.5. In certain aspects, the surface has a pH of at least 8.0.

The catalysts of the present disclosure, optionally comprising co-catalysts and additives, may be prepared according to methods known in the art. Suitable promoters and additives include silver nitrate, cerium oxide, and zinc oxide. Additives are included to mitigate, for example, bacterial growth and to prevent UV-induced degradation of the catalyst and the breathable substrate. The catalysts, promoters, and additives of the present disclosure may be applied to the grid by a variety of methods, including but not limited to, gel-sol methods, coating, impregnation, and powder coating. In other aspects, the catalysts, promoters, and additives of the present disclosure may be applied to the mesh by roll coating, casting, ultrasonic spraying, and roll coating. The method of applying the catalyst, promoter and additives as provided herein is suitable if it provides and includes a grid that holds an underlying air permeable substrate as cited above.

In one aspect, the catalyst mixture is applied to the mesh using a sol-gel process that includes using an alcoholic solution of a metal salt (alcoholic metal salt) as the catalytic material. In certain aspects, the metal salt is Ti (OR)₄. The application of the catalyst mixture using the sol-gel method may further include organic and inorganic salts in an alcohol solution to perform a hydration reaction, thereby manufacturing the organometallic compound in a gel form. The sol-gel process may further comprise a co-catalyst, e.g. WO₃、SnO₂、Fe₂O₃Or ZnO. The gel solution may be applied by dipping the grid into the gel solution or coating the solution onto the air permeable substrate structure. Can be controlled by controlling the speed of immersion or by providing one or more coatingsThe thickness of the catalyst mixture applied to the substrate is made. After drying, the coated substrate is baked and then sintered at high temperature. In certain aspects, the catalytic mixture can further comprise a noble metal or a transition metal. In some aspects, the catalyst mixture may further comprise a noble metal, such as Au, Pd, Pt, or Ag, and some transition metals, such as MoO₃、Nb₂O₅、V₂O₅、CeO₂Or Cr₂O₃。

The present disclosure provides and includes an apparatus having a light source capable of illuminating a gas permeable substrate structure having a catalyst on a surface thereof. Without being limited by theory, upon irradiation, the catalyst absorbs photons of the appropriate wavelength and imparts valence band electron energy. The valence band electrons are excited to the conduction band to generate electron-holes or valence band holes. In the absence of adsorbed chemical species, the excited electron will decay and recombine with the valence band hole. Recombination is prevented when the valence band holes trap electrons from oxidizable species, preferably molecular water, adsorbed on active surface sites on the photocatalyst. At the same time, the reducible species, preferably molecular oxygen, adsorbed on the catalyst surface can trap conduction band electrons.

Light sources suitable for use in the devices of the present disclosure include broad spectrum and narrow spectrum emission sources. In certain aspects, the light source can emit light in the Ultraviolet (UV) spectrum. In other aspects, the light source can emit light in the visible spectrum. In other embodiments, the light source may emit light in both the visible spectrum and the ultraviolet spectrum.

Suitable light sources according to the present disclosure include, but are not limited to, lasers, Light Emitting Diodes (LEDs), incandescent lamps, arc lamps, standard fluorescent lamps, u.v. lamps, and combinations thereof. In certain aspects, the light source is a light emitting diode.

The present disclosure provides and includes a gas permeable substrate structure coated with a catalyst mixture using light of a suitable wavelength and intensity. As provided above, the selection of a suitable irradiation wavelength depends on the catalyst and may be adjusted by the presence of one or more promoters. In certain aspects, the light source provides ultraviolet light. In one aspect, the wavelength of the ultraviolet light is from 190 nanometers to 410 nanometers. In some aspects, if the light source is likely to provide light having a wavelength less than 190 nanometers, the device may further be provided with suitable filters to block light at wavelengths of 190 nanometers and below. More specifically, certain devices of the present disclosure exclude light having a wavelength of 187 nanometers or less.

One of ordinary skill in the art will recognize that the generation of ozone will result in the reduction of PHPG gas to water and oxygen:

O₃ + H₂O₂ H₂O + 2O₂

thus, prior art designs for generating ozone are incompatible with the methods and apparatus of the present disclosure. As described above, for catalysts containing titanium dioxide, avoiding light at wavelengths below 190 nm greatly reduces or even eliminates ozone production and results in higher PHPG production rates.

In certain aspects, the device includes an ultraviolet light source capable of illuminating the titanium dioxide-containing catalyst mixture with light in the range of 190 nanometers to 410 nanometers and may further include a filter to block light at wavelengths of 190 nanometers and below. In other aspects, the device includes an ultraviolet light source that provides illumination of the titanium dioxide-containing catalyst mixture and further includes a promoter that expands the photocatalytic absorption band into the visible spectrum. In one aspect, the catalyst mixture can comprise tungsten trioxide, WO, that absorbs light in the visible spectrum₃. In one aspect, the light source can include light between 190 nanometers and 460 nanometers.

In other aspects, the light source provides ultraviolet light having a spectrum of 190 nanometers to 460 nanometers, wherein 70% of the power is provided between 340 nanometers to 380 nanometers. In one aspect, at least 90% of the ultraviolet light is emitted between 340 nanometers and 380 nanometers. In another aspect, 99% of the ultraviolet light is emitted between 350 nanometers and 370 nanometers. In yet another aspect, the ultraviolet light has a wavelength in the UVA range (315 nm to 400 nm). In some aspects, the light in the UVA range has a maximum intensity concentrated at or near 362 nanometers. In another aspect, the ultraviolet light has a wavelength in the UVA range and less than 1% is in the UVB range (280 to 315 nanometers). In yet another aspect, the ultraviolet light has a wavelength in the UVA range and less than 0.1% is in the UVB range. In another aspect, the ultraviolet light has a wavelength in the UVA range and less than 0.05% is in the UVB range.

In an aspect according to the present disclosure, the light source may have a power of 0.1W to 150W. In other aspects, the light source can be up to 150W. In another aspect, the power may be at least 0.1W. In one aspect, the light source has a power of at least 1W. In yet another aspect, the power may be greater than 2.5W. In one aspect, the power may be about 5W. In one aspect, the power may be 20W. In certain aspects, the light source may be up to 100W in power. In certain aspects, the power is less than 100W to minimize the disruption of the generated PHPG. In other aspects, the power is 1W to 50W. In certain aspects, the power of the light source is 40 to 50W.

The disclosed apparatus includes providing at least 0.1 watts per square inch (W/in) measured at the surface of the air permeable substrate²) A light source of intensity of (1). In some aspects, the light source has up to 150W/in²The strength of (2). In other aspects, the light source output has a 0.1W/in²To 10W/in²Light of the intensity of (1). In one aspect, the intensity of the light striking the breathable substrate is about 5W/in². In certain aspects, the power of the substrate surface may be 1W/in²To 10W/in². In another aspect, the intensity may be 2W/in²To 8W/in². In one aspect, the intensity can be 3W/in²To 7W/in². In yet another aspect, the power may be 4W/in²To 6W/in²。

The disclosed device is distinguished from devices designed for filtration that utilize photocatalysis to generate reactive species. More specifically, the presence of contaminants such as dust, pollen, bacteria, spores and particles that can clog the open spaces of the mesh of the air permeable substrate degrades the devices of the present disclosure. Similarly, Volatile Organic Compounds (VOCs) that can react with reactive species, including hydrogen peroxide, reduce the yield of PHPG and distribution of PHPG into space. Notably, while the PHPG-producing devices of the present disclosure are effective in reducing VOCs in a space, it is preferred to minimize or eliminate VOCs introduced into the device itself. Thus, to maintain the efficiency of the plant and maximize PHPG production, the plant of the present disclosure may include one or more filters. As will be noted, the choice of filter may depend on the application and the type of space to be processed with the PHPG. For example, a clean room (where the air has been treated to eliminate dust, VOCs, and other contaminants) may use a device having a housing, air distribution mechanism, a light source, and an air permeable substrate with a catalyst on its surface without the need for a pre-filter. In contrast, household devices may require a dust filter and may further require a carbon filter to absorb VOCs. In certain aspects, inclusion of the additional filter provides for extended life of the gas permeable catalyst coated substrate and provides for extended production of PHPG.

Filters used to purify air independent of the occurrence of PHPG depend on the air quality at the location where the device is used. In HVAC systems having high quality air achieved by the filters of the HVAC system, a filter may not be necessary before the air stream passes through the air permeable substrate of the PHPG device itself. The same applies to stand-alone devices operating in areas where high air quality is present. When necessary, the filters are generally selected from those known in the art that can achieve the desired filtration without impeding the air flow as much as possible. The filter is further selected from those known in the art such that the filter itself does not introduce particulates or gases into the air stream. Suitable filters that combine the functions of removing particulate matter as well as gaseous contaminants are known in the art. The filters need to be replaced periodically, with a frequency that depends on the load placed on the filter-due to a higher air quality (lower replacement frequency) or a lower air quality (higher replacement frequency).

In most applications, three filtration problems apply. In some applications, the particulate matter or dust can foul the substrate matrix and the catalyst itself, and therefore a particulate filter can be used that is sufficient for the needs of the site. In certain common aspects, a high airflow pleated MERV 18 filter is used. In other applications, the volatile organic hydrocarbons may require filtration and this may be achieved using many different activated carbon or carbon impregnated filters known in the art. In still other applications, it is desirable to remove certain inorganic gases, such as nitrogen oxides, by filtration. For the removal of nitrogen oxides, zeolite filters are generally used. In some aspects, the PHPG apparatus comprises an impregnated zeolite filter that can remove volatile organic hydrocarbons and nitrogen oxides in a single, combined material and stage. Suitable filters that can remove particles of various sizes that would clog the air permeable substrate or contaminate and passivate the catalytic surface are known in the art.

In aspects of the present disclosure, the device may further comprise one or more filters designed to remove contaminants selected from the group consisting of nitrogen oxides (NOx), sulfur oxides (SOx), volatile organic compounds, dust, bacteria, pollen, spores, and particles. In certain aspects, the device comprises one or more filters selected from an organic vapor filter, a particulate filter, a high efficiency filter, a hydrophobic filter, an activated carbon filter, or a combination thereof.

In certain aspects, the pre-filter removes volatile organic compounds, NOx, and SOx. In some aspects, the filter removes aldehydes, such as formaldehyde or acetaldehyde. In other aspects, the filter removes VOCs including toluene, propanol, and butenes. In still other aspects, the prefilter removes NO and NO, the nitric oxides NO and NO₂(e.g., NOx). In other aspects, the pre-filter removes sulfur and oxygen containing compounds referred to as SOx. SOx compounds removed by the filters of the present disclosure include SO, SO₂、SO₃、S₇O₂、S₆O₂、S₂O₂Or a combination thereof. The prefilters of the present disclosure may be used to remove any combination of VOCs, NOx, and SOx.

In certain aspects, the device comprises a filter comprising a microporous aluminosilicate mineral. In one aspect, the filter of the present device may be a zeolite filter. In one aspect, the zeolite can be analcime, chabazite, clinoptilolite, heulandite, natrolite, phillipsite, or stilbite. In certain aspects, the zeolite can be a synthetic zeolite. In one aspect, the device includes a zeolite filter for removing NOx, SOx, or both. Suitable filters are known in the art.

In other aspects, the device includes a filter, which includes a particulate filter. In certain aspects, the particulate filter is a 3m ultra allergan filter. Suitable examples of particulate Filters are available from Air Filters, Inc, which provides Astro-cell dense pleated Filters (mini-pleat Filters). One of ordinary skill in the art will be able to select a filter that provides an appropriate level of air flow and resistance to air flow to provide sufficient air flow through the air permeable substrate as recited above.

In still other aspects, filters suitable for use in the devices of the present disclosure include carbon filters, charcoal filters, or activated carbon filters. In some aspects, the filter is a GAC (particulate activated carbon) carbon filter. In one aspect, the GAC is a filter made of coconut shells. In one aspect, the filter is powdered activated carbon (R1) (PAC). In another aspect, the filter is an Extruded Activated Carbon (EAC) filter. In one aspect, the filter may be a Bead Activated Carbon (BAC) filter. In one aspect, the filter may be an impregnated carbon filter. In certain aspects, an impregnated carbon filter is included in the apparatus to remove hydrogen sulfide (H)₂S) and mercaptans. Suitable impregnated carbon filters are known in the art.

Air filtration in a device according to the present disclosure provides air flow across an air-permeable substrate layer with low contaminant and photocatalytic inhibitor levels.

In certain preferred embodiments, the present application provides the following:

item 1. an apparatus for producing non-hydrated Purified Hydrogen Peroxide Gas (PHPG), the apparatus comprising:

a. a housing;

b. an air distribution mechanism providing an air flow;

c. breathable substrate structure comprising a grid having an open area of 20% to 60%, 25x10^-6A pore size of from meter (microns) to 220 microns, a line thickness of from 48 microns to 175 microns, and having a catalyst on the surface;

d. a light source comprising Ultraviolet (UV) light at a wavelength greater than 187 nanometers (nm); and is

Wherein

The air stream passes through the air permeable substrate structure; and is

The device, when operated, produces non-hydrated PHPG and directs it out of the shell.

The apparatus of item 2. item 1, wherein the air flow comprises an angle of incidence to the substrate structure of greater than 14 °.

Item 3. the apparatus of item 1, wherein the air stream comprises air having a humidity of at least 5%.

Item 4. the device of item 1, wherein the gas permeable substrate structure is a mesh having an open area percentage of 30% to 40%.

Item 5 the apparatus of item 1, wherein the ultraviolet light irradiates the air permeable substrate structure with light having an intensity of 0.1 watts per square inch to 150 watts per square inch at the substrate surface.

Item 6. the apparatus of item 5, wherein the intensity is 2.5 to 7.4 watts per square inch.

Item 7. the device of item 1, wherein the ultraviolet light comprises a wavelength of 190 nanometers to 460 nanometers.

Item 8. the device of item 7, further comprising a filter to block ultraviolet light having a wavelength of 188 nanometers or less.

Item 9 the device of item 8, wherein the ultraviolet light has a wavelength of 340 nanometers to 380 nanometers.

The apparatus of item 10. item 9, wherein at least 90% of the power of the light is emitted between 340 nanometers and 380 nanometers.

Item 11 the device of item 8, wherein less than 1% of the light is ultraviolet B radiation having a wavelength of 280 to 315 nanometers.

Item 12. the apparatus of item 1, further comprising one or more filters to remove one or more contaminants selected from the group consisting of nitrogen oxides (NOx), sulfur oxides (SOx), Volatile Organic Molecules (VOM), household dust, pollen, dust mite debris, mold spores, pet dander, smoke, haze, and bacteria from the air stream prior to flowing through the air permeable substrate structure.

Item 13. the apparatus of item 1, wherein the air stream flows through the gas permeable substrate structure at a flow rate of 5 nanometers per second (nm/s) to 10,000 nm/s.

Item 14. the device of item 1, wherein the catalyst on the gas permeable substrate structure further comprises a hygroscopic additive, wherein the hygroscopic additive is selected from the group consisting of sodium bicarbonate, potassium bicarbonate, sodium carbonate, potassium carbonate, magnesium bicarbonate, sodium hydroxide, potassium hydroxide, magnesium hydroxide, zinc chloride, calcium chloride, magnesium chloride, sodium phosphate, potassium phosphate, magnesium phosphate, carnallite, ferric ammonium citrate, nylon, Acrylonitrile Butadiene Styrene (ABS), polycarbonate, cellulose, and poly (methyl methacrylate).

Item 15. an apparatus for generating non-hydrated Purified Hydrogen Peroxide Gas (PHPG) when installed in a heating, ventilation and air conditioning (HVAC) system, the apparatus comprising:

a. breathable substrate structure comprising a grid having an open area of 20% to 60%, 25x10^-6A pore size of from meter (microns) to 220 microns, a line thickness of from 48 microns to 175 microns, and having a catalyst on the surface; and

b. a light source comprising Ultraviolet (UV) light at a wavelength greater than 187 nanometers (nm);

wherein in operation air flows from the HVAC system through the air permeable substrate structure and the device produces PHPG and directs the PHPG away from the air permeable substrate structure having the catalyst on its surface and into a space being heated, ventilated and conditioned.

Item 16 the apparatus of item 15, wherein the air flow comprises an incident angle to the substrate structure of at least 14 °.

Item 17 the device of item 15, further comprising a filter to block ultraviolet light having a wavelength of 188 nanometers or less.

Item 18 the apparatus of item 15, wherein the air has a residence time on the catalyst surface of less than 1 second.

Item 19. a breathable substrate structure, comprising:

a. having an open area percentage of 10% to 60% and 25x10 after coating^-6A grid of pore sizes in the range of meters (microns) to 220 microns, and

b. a catalyst located on a surface of the mesh,

wherein the catalyst is a metal or metal oxide catalyst selected from the group consisting of titanium dioxide, copper oxide, zinc oxide, iron oxide, tungsten trioxide, and mixtures thereof.

Item 20. the apparatus of item 1, wherein the mesh comprises an open area of 30%, a pore size of 51 microns, and a line thickness of 61 microns.

Item 21. the apparatus of item 1, wherein the mesh comprises an open area of 37%, a pore size of 102 microns, and a line thickness of 114 microns.

Item 22 the apparatus of item 1, wherein the mesh comprises an open area of 45%, a pore size of 152 microns, and a line thickness of 130 microns.

Item 23. the apparatus of item 1, wherein the mesh comprises an open area of 41%, a pore size of 203 microns, and a line thickness of 152 microns.

Item 24. the apparatus of item 15, wherein the mesh comprises an open area of 30%, a pore size of 51 microns, and a line thickness of 61 microns.

Item 25. the apparatus of item 15, wherein the mesh comprises an open area of 37%, a pore size of 102 microns, and a line thickness of 114 microns.

Item 26 the apparatus of item 15, wherein the mesh comprises an open area of 45%, a pore size of 152 microns, and a line thickness of 130 microns.

Item 27. the apparatus of item 15, wherein the mesh comprises an open area of 41%, a pore size of 203 microns, and a line thickness of 152 microns.

Item 28 the breathable substrate structure of item 19, wherein the mesh comprises an open area of 30%, a pore size of 51 microns, and a line thickness of 61 microns.

Item 29 the breathable substrate structure of item 19, wherein the mesh comprises an open area of 37%, a pore size of 102 microns, and a line thickness of 114 microns.

Item 30 the breathable substrate structure of item 19, wherein the mesh comprises 45% open area, a pore size of 152 microns, and a line thickness of 130 microns.

Item 31 the breathable substrate structure of item 19, wherein the mesh comprises an open area of 41%, a pore size of 203 microns, and a line thickness of 152 microns.

Item 32 the apparatus of item 1, wherein the source of ultraviolet light is a Light Emitting Diode (LED).

It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable subcombination or as suitable in any other described embodiment of the invention. Certain features described in the context of various embodiments are not to be considered essential features of those embodiments, unless the embodiment is not practiced without these elements.

Various embodiments and aspects of the present invention as delineated hereinabove and as claimed in the claims section below are supported experimentally in the following examples. The following examples are presented for illustration and are not to be construed as limiting.

Examples

Example 1 measurement of PHPG, ozone, VOC, temperature and humidity:

all PHPG concentration readings were performed with Draeger product. Pac III, Polytron 7000 or Draeger tubes were used in all tests, generally according to the manufacturer's instructions. The Polytron displays a digital reading as air is drawn across the grid sensor. Draeger tubes are most often cut at both ends and used in an ACCURO ™ pump. The tube was pumped 100 times and PHPG levels were determined by observing the discoloration in the crystal according to the manufacturer's instructions. PAC III has proven generally less effective in the measurement of very low PHPG levels.

Measurements of ozone, VOC, temperature and humidity were all achieved using standard devices. It was found that Draeger tubes designed to detect hydrogen peroxide concentrations as low as 0.10ppm after 2000 cubic centimeters of air intake provided lower concentration readings accurate to within 0.005ppm when larger volumes were drawn by calibrated pumps-e.g., a Draeger tube indicating 0.10ppm after 4000 cubic centimeters of intake measured an approximate PHPG concentration of 0.05 ppm, and a Draeger tube indicating 0.10ppm after 6000 cubic centimeters of intake measured an approximate PHPG concentration of 0.033 ppm.

Example 2 PHPG apparatus for testing breathable substrates

The PHPG generating device 20 as illustrated in fig. 2A to 2B, which comprises a housing 205, an air-permeable substrate 201, an air distribution mechanism 203, and a light source 203, was used for testing. By adding 10 to 35% of TiO in the anatase form₂The breathable substrate 201 was prepared by dip-coating a polyester mesh in a slurry in water and allowed to air dry. To prevent clogging of the openings of the mesh, air is blown through the air permeable substrate. The air distribution mechanism was set at its highest setting and provided an air flow of approximately 115 cubic feet per minute. Room humidity was maintained at about 55%. The PHPG generating unit was operated in a 140 square foot enclosed room with an 8 foot ceiling for 1 hour and then the steady state level of PHPG was measured. Without continued operation of the PHPG generating device, the PHPG dissipates and is undetectable in about 5 minutes. Ozone was not detected in any of the tests.

Example 3 Effect of grid Change on PHPG production

By replacing TiO as provided in Table 4₂The coated breathable substrate 201 and tested as described in example 2, exhibited the effect of grid variation on PHPG production.

TABLE 4 comparison of breathable substrates

Line thickness (inches)	Hole size (inch)	Strand/inch	Line thickness (mu m)	Hole size (mu m)	Strand/cm	Open area%	PHPG (ppm)
								0.0019	0.001	460	48	25	181	21	0.1
0.0024	0.002	280	61	51	110	30	0.4
								0.0045	0.004	140	114	102	55	37	0.3
0.0051	0.006	109	130	152	43	45	0.3
								0.006	0.008	80	152	203	31	41	0.6
0.013	0.012	50	330	305	20	37	n/d
								0.016	0.032	24	406	813	9	58	n/d

n/d = not detected.

Example 4 Effect of incident Angle on PHPG yield

The device according to example 2 was modified by attaching a 10-inch aluminum adapter (adaptor) capable of rotating the gas permeable substrate 201 as a cover cap (shroud) to the top of the device. A breathable substrate having 152 micron lines and 41% open area was placed in the device. The initial steady state level of PHPG measured at 90 ° air flow was 0.7 ppm. The breathable substrate 201 was rotated in increments of 2 ° within the hood and the steady state level of PHPG was measured until no more hydrogen peroxide was detected by the polytron. From about 90 deg. to about 68 deg. (e.g., 22 deg. from vertical) PHPG production is maintained. Starting at about 68 deg., the PHPG level steadily decreases from 68 deg. to about 14 deg. at about 0.1 ppm/10 deg.. When the incident angle of the air flow was below 14 °, no PHPG generation was detected.

While the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims.

All publications, patents, and patent applications mentioned in this specification are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.

Claims (10)

1. An apparatus for generating non-hydrated Purified Hydrogen Peroxide Gas (PHPG), the apparatus comprising:

a. a housing;

b. an air distribution mechanism providing an air flow;

c. breathable substrate structure comprising a grid having an open area of 20% to 60%, 25x10^-6A pore size of from meter (microns) to 220 microns, a line thickness of from 48 microns to 175 microns, and having a catalyst on the surface;

d. a light source comprising Ultraviolet (UV) light at a wavelength greater than 187 nanometers (nm); and is

Wherein

The air stream passes through the air permeable substrate structure; and is

The device, when operated, produces non-hydrated PHPG and directs it out of the shell.

2. An apparatus for generating non-hydrated Purified Hydrogen Peroxide Gas (PHPG) when installed in a heating, ventilation and air conditioning (HVAC) system, the apparatus comprising:

a. breathable substrate structure comprising a grid having an open area of 20% to 60%, 25x10^-6A pore size of from meter (microns) to 220 microns, a line thickness of from 48 microns to 175 microns, and having a catalyst on the surface; and

b. a light source comprising Ultraviolet (UV) light at a wavelength greater than 187 nanometers (nm);

wherein in operation air flows from the HVAC system through the air permeable substrate structure and the device produces PHPG and directs the PHPG away from the air permeable substrate structure having the catalyst on its surface and into a space being heated, ventilated and conditioned.

3. The apparatus of claim 1 or 2, wherein the air flow comprises an angle of incidence to the substrate structure of greater than 14 °.

4. The apparatus of claim 1 or 2, wherein the air stream comprises air having a humidity of at least 5%.

5. The device of claim 1 or 2, wherein the air permeable substrate structure is a mesh having an open area percentage of 30% to 40%.

6. The apparatus of claim 1 or 2, wherein the ultraviolet light irradiates the air permeable substrate structure with light having an intensity of 0.1 watts per square inch to 150 watts per square inch at the substrate surface.

7. The device of claim 6, wherein the intensity is 2.5 to 7.4 watts per square inch.

8. The device of claim 1 or 2, wherein the ultraviolet light comprises a wavelength of 190 nanometers to 460 nanometers.

9. The device of claim 8, further comprising a filter that blocks ultraviolet light having a wavelength of 188 nanometers or less.

10. A breathable substrate structure comprising:

a. having an open area percentage of 10% to 60% and 25x10 after coating^-6A grid of pore sizes in the range of meters (microns) to 220 microns, and

b. a catalyst located on a surface of the mesh,

wherein the catalyst is a metal or metal oxide catalyst selected from the group consisting of titanium dioxide, copper oxide, zinc oxide, iron oxide, tungsten trioxide, and mixtures thereof.