Device, system, and method for producing advanced oxidation products
10421060 ยท 2019-09-24
Assignee
Inventors
Cpc classification
A61L2209/21
HUMAN NECESSITIES
B01J19/10
PERFORMING OPERATIONS; TRANSPORTING
B01J35/19
PERFORMING OPERATIONS; TRANSPORTING
B01J21/063
PERFORMING OPERATIONS; TRANSPORTING
International classification
A61L9/04
HUMAN NECESSITIES
B01J19/10
PERFORMING OPERATIONS; TRANSPORTING
B01J21/06
PERFORMING OPERATIONS; TRANSPORTING
B01J35/00
PERFORMING OPERATIONS; TRANSPORTING
Abstract
The present invention relates generally to an advanced oxidation process for providing advanced oxidation products to an environment. More particularly, the present invention provides a wick structure and hydrophilic granules for use in an advanced oxidation process, and methods of making the same. The wick structure and hydrophilic granules may be configured to collect and concentrate water vapor, so that the water vapor may subsequently be used to generate advanced oxidation products that react with and neutralize compounds in an environment, including microbes, odor causing chemicals, and other organic and inorganic chemicals.
Claims
1. Hydrophilic granules configured for use in an advanced oxidation process, wherein the granules comprise a base material, wherein the base material is porous and comprises a hydrophilic material, a catalytic material, and a ceramic matrix, wherein the catalytic material comprises titanium dioxide, wherein at least a portion of the titanium dioxide is in anatase crystal form, wherein the hydrophilic material is formulated to absorb and release water and comprises magnesium carbonate.
2. The hydrophilic granules of claim 1, wherein the ceramic matrix comprises cerium oxide and aluminum oxide.
3. The hydrophilic granules of claim 1, wherein greater than 99% of the titanium dioxide is in anatase crystal form.
4. The hydrophilic granules of claim 1, wherein the base material further comprises one or more additional catalytic materials.
5. The hydrophilic granules of claim 4, wherein the one or more additional catalytic materials are selected from the group consisting of rhodium, silver, copper, zinc, platinum, nickel, erbium, yttrium, fluorine, sodium, ytterbium, boron, nitrogen, phosphorus, oxygen, thulium, silicon, niobium, sulfur, chromium, cobalt, vanadium, iron, manganese, tungsten, ruthenium, gold, palladium, cadmium, and bismuth, and combinations thereof.
6. The hydrophilic granules of claim 1, wherein the base material comprises channels and pores, and has an internal surface area of at least 750 m.sup.2 per gram.
7. The hydrophilic granules of claim 2, wherein the cerium oxide and the aluminum oxide form a ceramic matrix that provides structural support.
8. The hydrophilic granules of claim 1, wherein the magnesium carbonate forms a sponge-like structure that is infused with the titanium dioxide.
9. The hydrophilic granules of claim 1, wherein the magnesium carbonate is anhydrous and amorphic.
10. The hydrophilic granules of claim 1, wherein at least a portion of the titanium dioxide is in the form of nanoparticles.
11. Hydrophilic granules configured for use in an advanced oxidation process, wherein the granules comprise a base material, wherein the base material is porous and comprises a hydrophilic material, a catalytic material, and a ceramic matrix, wherein the catalytic material comprises titanium dioxide, wherein at least a portion of the titanium dioxide is in anatase crystal form, wherein the hydrophilic material is formulated to absorb and release water, and wherein the base material is formed by a process comprising the steps of: mixing respective precursors for the hydrophilic material, the catalytic material, and the ceramic matrix; and after the precursors are mixed, heating the base material at a temperature at or above 650 F.
12. The hydrophilic granules of claim 11, wherein the hydrophilic material comprises magnesium carbonate.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings, which are incorporated herein and form part of the specification, illustrate various embodiments of the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the pertinent art to make and use the invention. In the drawings, like reference numbers identify identical or functionally similar elements.
(2) A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
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DETAILED DESCRIPTION OF THE INVENTION
(11) Detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention, which can be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure. Further, the terms and phrases used herein are not intended to be limiting; but rather, to provide an understandable description of the invention.
(12) Overview
(13) A device, system, and method for producing advanced oxidation products utilizing advanced oxidation processes are provided. Advanced oxidation products (AOPs) are much more effective than traditional oxidants at reacting with compounds, such as microbes, odor causing chemicals, and other inorganic and organic chemicals. Advanced oxidation products are considerably stronger than typical cleaning agents such as chlorine. Generally, advanced oxidation products will react with compounds that typically will not react with other common oxidants. The device, system, and method of the present invention are specifically focused at promoting the production of the peroxide species hydrogen peroxide, but can also generate numerous other AOPs. Advanced oxidation products formed by advanced oxidation processes in accordance with various embodiments of the instant invention include, hydroxyl radicals, hydro peroxides, ozonide ions, hydroxides, and super oxide ions.
(14) The first step for forming advanced oxidation products using the devices, systems, and methods of the present invention is targeting the capture of water vapor found within air, e.g. ambient air and/or duct air. Capture of water vapor is facilitated by the use of a novel wick structure, described below in detail. The wick structure of the present invention is comprised of hydrophilic materials coupled with an extremely high internal surface area that promotes extreme absorption of water vapor.
(15) As water vapor from the air is absorbed onto the exterior surface of the wick structure from the ambient air, the gas phase water vapor changes into liquid form. The liquid water is then transported via molecular transport across the thickness of the wick structure, where it is ultimately released, rapidly and continually, into an advanced oxidation reaction chamber (AORC). The actual hydraulic movement across the wick structure is induced by creating a differential moisture concentration gradient within the wick structure itself. As explained in further detail below, the differential moisture concentration gradient driving hydraulic movement is generated by providing heat and ultrasonic energy at the inner surfaces of the wick structure.
(16) Upon arriving at the inner surface of the wick structure, the liquid water then quickly transforms back to the gas phase as vaporized water. This gas-liquid-gas phase pump (GLG-Pump) mechanism is designed specifically to collect the exterior ambient humidity and then release and concentrate it inside the AORC.
(17) AOPs may then be formed from the water vapor in the AORC by several different methods. In exemplary embodiments, multi-wavelength UV light sources (10-400 nm) are targeted onto the inner surface of the wick structure. AOPs are generated when light energy from the ultraviolet light source reacts with oxygen, ozone (if desired), water present on or in the wick structure, and one or more photocatalytic materials provided integrally in the wick structure. The inventors have surprisingly found that use of the novel wick structure described herein also allows for generation of AOPs alternatively using visible (400 nm-750 nm), or other forms of light such as near infrared light (750 nm-2500 nm). AOPs may also be produced via targeted ultrasonic sonolysis reactions within the wick structure itself, and also within the AORC. Additional sonolysis and photocatalytic reactions can take place in a secondary AOP reaction chamber, in accordance with alternative embodiments of the disclosed devices, systems, and methods
(18) These various method steps, and the components utilized therein, will be described in further detail below.
(19) Wick Structure
(20) The wick structure comprises a base material including a hydrophilic material, a catalytic material, and a ceramic matrix. The base material of the wick structure is full of tiny channels and connected pores equating to a huge internal surface area, in excess of 750 m.sup.2 per gram. The higher the porosity of the base material, the more effective the hydraulic attraction (water absorption), and the more surface area available for photocatalytic reactions to occur.
(21) The wick structure may be provided in several different forms, as shown in
(22) In preferred embodiments, the surface area of exterior surface of the wick structure is at least 50% greater than that of the surface area of the interior surface. This ensures that the collected vapor will be concentrated when delivered to the inner surface of the wick structure.
(23) The body of the wick structure, whether in molded or granular form, comprises a base material comprising a hydrophilic material, a catalytic material, and a ceramic matrix. The characteristics of each of these wick structure components are described below.
(24) The hydrophilic material of the wick structure is formulated to have the unique ability to absorb high quantities of water vapor (i.e. to be extremely hydrophilic). Notably, the hydrophilic material is formulated to also re-release the vast majority of this absorbed water back into the air. It is preferred that the hydrophilic material in the wick structure comprises anhydrous magnesium carbonate. Additionally, it is preferred that the magnesium carbonate is amorphous. In testing performed by the inventors, it was found that the magnesium carbonate can be formulated to re-release up to 95% of the absorbed water, in exemplary embodiments of the instant invention.
(25) The catalytic material in the wick structure plays a key role in catalyzing the formation of advanced oxidation products within and at the surface of the wick structure. The catalytic material is preferably titanium dioxide. At least a portion of the titanium dioxide in the wick structure is in anatase crystal form. In exemplary embodiments, almost all of the titanium dioxide is in anatase crystal form, i.e. at least 90%, at least 95%, or at least 99% of the titanium dioxide is in anatase crystal form. In exemplary embodiments, at least a portion of the titanium dioxide is in the form of nanoparticles.
(26) The ceramic matrix provides structural support, and allows for production of a more rigid final material. Preferably, the ceramic matrix comprises cerium oxide and aluminum oxide (Al.sub.2O.sub.3). The cerium oxide acts as a binder with the Al.sub.2O.sub.3. Additionally, the cerium oxide has inherent hydration properties, i.e. it is hydrophilic, and thus further enhances the effect of the MgCO.sub.3 described above. The cerium oxide also has inherent catalytic properties.
(27) In addition, one or more known catalytic enhancers or dopants can optionally be added during the process of forming the wick structure, such that the catalytic enhancer(s) or dopant(s) are integrated into the final wick structure. Known catalytic enhancers and dopants appropriate for inclusion in the wick structure include, but are not limited to, rhodium, silver, copper, zinc, platinum, nickel, erbium, yttrium, fluorine, sodium, ytterbium, boron, nitrogen, phosphorus, oxygen, thulium, silicon, niobium, sulfur, chromium, cobalt, vanadium, iron, manganese, tungsten, ruthenium, gold, palladium, cadmium, and bismuth, and combinations thereof.
(28) A unique feature of the wick structure base material is its ability to be cast into unique shapes and forms. This allows for precision control of its final shape and, by design, also its structural strength. The structure's shape and design can be altered based on the average humidity of the ambient environment of its intended use. For example, by increasing the ratio of the outer surface area to inner surface area, a targeted increase in available AORC water vapor will occur internal to the wick structure. For example, in a ambient environment with an average relative humidity of 35%, increasing the outer to inner surface ratio to 3:1 can achieve a 99.9% relative humidity microclimate at the inner surface.
(29) Scanning electron micrographs of a base material for a wick structure are shown in
(30) As further illustrated in the micrographs, the surface of the wick structure base material is generally irregular and uneven, creating microprojections extending from the surface. The presence of such microprojections further increases the effective surface area. In
(31) Reflected Electro Mechanical Energy System
(32) In exemplary embodiments of the invention, a Reflected Electro Mechanical Energy System is used to facilitate movement of liquid water across the thickness of the wick structure, and also to produce AOPs via sonolysis reactions. As shown in
(33) The one or more ultrasonic energy emitters provide ultrasonic energy in two simultaneous waves. The first wave has a frequency in the range of 20-30 kHz, and the second wave has a frequency in the range of 1.5-4 MhZ. Preferably, the frequency of the first wave is 26 kHz and the frequency of the second wave is 2 Mhz. The number and power of the ultrasonic emitters is determined by the size of final required structure. Those of ordinary skill in the art will recognize the size of the final structure can be configured depending on the reaction output desired and the space to output ratio required for the AOP process.
(34) For added effect, a frequency hopping scheme can also be employed. A single ultrasonic driver is provided, wherein the driver varies the sonic transducer's emitted frequencies. The frequencies can be varied electronically, using various off-the-shelf IC chips in a custom circuit for the application. Alternatively, the frequencies can be varied mechanically by using multiple single frequency sonic transducers in an array, each one with a different frequency to get a similar net effect. Frequency hopping enhances evaporation rates by inducing resonant responses from the different mediums within the wick structure.
(35) The digital reflectors 13 are configured to direct and evenly disperse the produced ultrasonic energy 25 onto the interior walls of the wick structure 11, as illustrated in
(36) The digital reflectors 13 may comprise a plurality of smaller planar convex reflectors 24 that are specifically angled to reflect and disperse the ultrasonic energy onto targeted points or surfaces of the interior surface of the wick structure 33. There may be several thousand individual planar convex reflectors at the surface of each digital reflector. Typically, reflector panels are 0.0009 square inches or less, with center angles of 85 degrees.
(37) The ultrasonic energy emitter(s) 14 and the digital reflector(s) 13 are configured such that transmitted sonic waves 25 make contact with a reflector 13, and the sonic waves 25 are subsequently deflected toward specific targeted surfaces of the wick structure 11, while also being dispersed in a conical pattern. Each reflected wave will angle outward and then overlap the path of its adjacent reflector plane, effectively spreading the sonic energy 25 across the entire inner wall 33 of the wick structure 11 at multiple path angles. By deflecting the sonic energy into multiple sonic pathways and angles of contact, the digital reflector 13 design essentially bathes the entire irregular micro surfaces of the wick structure inner surface 33 with sonic energy. This reflector design essentially simulates the presence of thousands of individual ultrasonic emitting sources, all directed to specific locations across the entire wick structure inner surface. Using this multipath digital reflector design in lieu of a single flat unidirectional reflector completely eliminates any line of sight shadowing of the rough wick structure surfaces. In other words, the reflector design disclosed herein provides for much more complete surface coverage, and with a much lower output power requirement, to achieve the same coverage achieved by other configurations having additional components and complexity.
(38) The high frequency sonic waves striking the hydrophilic surfaces of the wick structure initiate micro oscillations of the water molecules within the airspaces of the wick structure. This process is most effective when pore and inter granule spacing is greater than of 0.04 microns, with 0.10 to 10 microns being considered ideal. The induced oscillation energy forms micro partial vacuum points within the wick structure itself, which in turn lowers the partial pressure at these locations. This causes water molecules from the wick's higher pressure outer surface to move towards the lower pressure zones near the wick's interior surface.
(39) The ultrasonic energy will also cause water droplets to begin to spontaneously cavitate at the interior surface of the wick structure. This cavitation process occurs in the water at the interior surface of the wick structure, and also in the water trapped within the smaller pores and spaces of the individual wick structure granules contained within the interior side of the wall of the wick structure. The ideal pore size to effect cavitation is from 0.003 to 0.39 microns.
(40) In the cavitation process, micro air bubbles form and rapidly expand within the water droplets. Once each air bubble is unable to expand any further, it rapidly collapses, releasing a large amount of energy as heat. These intense micro point sources of heat (as high as 4000K) cause a localized increase in temperatures of the wick structure, specifically within the region of the wick structure adjacent to the internal surface. Notably, a very high pressure wave is released upon bubble implosion. The increased temperature in turn lowers the water vapor pressure of the internal chamber side air in close proximity to these heated wick structure surfaces, promoting vaporization of the water from the inner surfaces of the wick into the air. In addition, this same cavitation process (the rapidly collapsing air bubbles) directly causes ultrasonic atomization of the water droplets into the air. This occurs when micro droplets of water are violently expelled into the surrounding air spaces upon implosion (cavitation), leading to their instantaneous evaporation into the surrounding air. The vaporization of water at the inner surfaces of the wick structure creates a moisture gradient across the thickness of the wick structure.
(41) Each of the processes mediated by the Reflective Electro Mechanical Energy System, including the moisture gradient, the heating of the inner surfaces due to cavitation, the vapor pressure reduction, the sonic cavitation, and the sonolysis, combine to pull water molecules from the wick structure's outer surface to the internal wick structure walls, and subsequently into the interior surfaces of the wick structure. This makes the water molecules available for forming AOPs.
(42) AOPs are formed in this system in several ways. When the cavitation process occurs, as described above, a large amount of energy is released. This released energy interacts directly with the effected water droplet (i.e. the water droplet undergoing cavitation) and the individual water molecules disposed within the walls of the wick structure, adjacent to the energy release. This causes instantaneous dissociation of the water and, ultimately, recombination into various AOPs, including hydroxyl radicals, super oxides, peroxides, and hydroxides. The produced AOPs are highly reactive, and will react with and destroy other undesirable organic and inorganic chemicals found in the environment. This results in a cleaning and purifying treatment of the surrounding air of an environment. These advanced oxidation product are very short lived and highly reactive such that after reacting with the compounds in an environment the advanced oxidation products will (over a short period of time) revert to safe and harmless oxygen and water molecules.
(43) Because of the unique ability of the wick structure to absorb high amounts of water, large quantities of water are present in the wick structure, and water is the primary compound available for reaction at the inner surfaces of the wick structure, where the sonolysis reactions occur. The water vapor adjacent to the inner surfaces of the wick structure reacts with the AOP products to produce a more stable moleculehydrogen peroxide (H.sub.2O.sub.2). For example, the reaction of two hydroxyl radicals creates H.sub.2O.sub.2. Additionally, the reaction of one superoxide ion (O.sup.2) with two water molecules produces two molecules of H.sub.2O.sub.2. This results in the production of high amounts of hydrogen peroxide in the AORC. Hydrogen peroxide is a strong oxidizer that can kill microbes, such as bacteria, mold, viruses, and can also react with chemicals in the environment to reduce odors. After hydrogen peroxide has been produced in the AORC, it travels out into airspaces external to the duct or unit, and will continue to treat air within these spaces, and surfaces within these spaces. This is a distinct advantage of the devices of the instant invention over conventional UV and PCO reactors. The vapor pressure reducing activities on the interior side of the wick structure also enhance the transfer of the air mass through the device. The micro projections of the wick structure protruding into the flowing air cause an increase in the surface air turbulence. This action also increases and aids in the effective airflow and mixing at the surface boundaries. The process reduces the surface boundary layers, allowing more air to actively flow into and pass out of the surfaces and structural projections. This micro mixing effect coupled with the high mass transfer of the air flow further increases the evaporation rate, thereby increasing the transfer of the liquid water from the wick structure into a water vapor within the inner AOP chamber environment. Each of these processes combine to pull additional water molecules from the wick structure's outer surface to the internal wick structure walls, and subsequently into the AOP chamber interior.
(44) Heat Source
(45) The actual hydraulic movement and concentration across the wick structure is induced by creating a differential moisture concentration gradient within the wick structure itself. As explained above, a differential moisture concentration gradient may be formed within the wick structure by supplying targeted high frequency ultrasonic energy to mechanically oscillate the trapped water molecules bound within the internal surfaces of the wick structure. Additionally, a moisture gradient may be generated by specifically heating the inner surface of the wick structure. Heating only the surfaces of the inner wall of the wick structure results in lowering the surface vapor pressure of the interior surface of the wick structure, promoting hydraulic movement across the wall thicknesses. Heating is controlled to ensure that only the inner surface of the wick structure, including the internal channels just below the inner surface, are thermally effected. A microclimate effect at the inner surface of the wick structure is the desired outcome. It is not desired to uniformly warm the entire wall thickness of the wick structure, because a temperature gradient must be maintained in order for this secondary moisture pump process to be effective.
(46) The heat required to heat the inner surface of the wick structure may be produced by specific thermal devices positioned adjacent to the wick structure. The thermal devices may be heaters, such as high resistance wire. Alternatively, the heat may be recovered from system components. Notably, the provision of targeted high frequency ultrasonic energy to the inner surface of the wick structure will also heat this surface. As explained above, the lower pressure at the inner wick surface caused by the provision of ultrasonic energy causes water droplets in this region to spontaneously cavitate. When this cavitation occurs, micro air bubbles form and rapidly expand within the water droplets. Once the air bubble is unable to expand any further, it rapidly collapses releasing a large amount of energy as heat. These intense micro point sources of heat (as high as 4000K) cause a localized increase in temperatures of the inner surfaces of the wick structure. In other embodiments, heat energy radiated from the light sources as infrared energy can also be harnessed to heat the inner wall surfaces of the wick structure, working in tandem with the sonolysis heating.
(47) Activation Light Source
(48) In addition to the advanced oxidation reactions induced by the ultrasonic sonolysis, additional AOP reactions will also take place in the system using the in situ photocatalytic surfaces of the wick structure. These additional advanced oxidation reactions occur as a direct result of applied light energy reacting with the photocatalytic surfaces. Additional reactions will also occur within the air plasma itself as the light energy reacts with the water and water-derived components (H and O) in the air.
(49) Light energy is applied to the interior surfaces of the wick structure. The photocatalysts that are integrated directly into the wick structure react with the applied light energy. A broad wavelength of light, generally from 100-2500 nm (ultraviolet, visible, near infrared), can be used to initiate these reactions, with best results occurring when light is provided at least one of the following wavelengths: 254 nm, 280 nm, 350 nm, 365 nm, 420 nm, 450 nm, or combinations thereof, or when light is provided in the visible or infrared range Those of skill in the art will recognize that varying the amounts of the co-catalysts in the final design will change the photocatalyst activation band gap and associated capabilities (i.e. increasing the effective light wavelength for its band gap activation). Those of skill in the art will also understand that, if desired, a combination of 185 nm light and 254 nm light may be provided to optionally provide an additional AOP pathway by way of the ozone decomposition reaction, further increasing the AOP potential.
(50) The activation light source can be any suitable light producing device, including but not limited to: low pressure mercury vapor sources, medium pressure mercury vapor sources, low pressure amalgam sources, LEDs, excimer sources, pulsed mercury/xenon arc, metal halide arc, lasers, etc. In one embodiment a low pressure mercury vapor source is preferred, as the heat generated by this type of lamp is adequate to result in the desired microclimate effect via warming the inner wall surfaces of the wick structure during its illumination.
(51) In some embodiments, an ultraviolet light source may be used as the activation light source. In other embodiments, a visible light source may be used as the activation light source. The band gap energy required for AOP surface activation of the catalytic materials within the wick structure can be adjusted by providing different dopants in the wick structure base material.
(52) Preferably, a broad spectrum ultraviolet light source is used to strike the surface of the interior surfaces of the wick structure, as well as to energize the surrounding atmosphere of an environment. The ultraviolet energy strikes the inner surfaces of the wick structure and activates production of hydroxyl radicals, super oxide ions and hydro peroxide on the surface. Because of the unique formulation of the wick structure, large quantities of water are collected from the air surrounding the outer surfaces of the wick structure and released into the AORC. The ultraviolet light energy energizes the catalytic molecules at the inner surface of the wick structure, causing the surface to react with water molecules primarily on the surface of the wick structure and also in the surrounding air, and causing them to split into AOPs such as hydroxyl radicals, super oxide ions, hydro peroxides, etc. in an advanced oxidation process. In this process, not only is the target surface active, but also is the air space between the inner surface of the wick structure and the ultraviolet light energy source.
(53) Electrodes
(54) In another embodiment, actively generated ions are introduced within the sonic field, i.e. the inner volume of the AORC wherein sonic energy is present. Introduction of these ions within the vaporization and sonolysis zone further enhances the production of the desired AOP products. These additional ions released directly within the flowing plasma of the wick structure and AORC increases the availability of the overall ionized molecular species. The hydro reactive molecules formed from the vaporization, catalytic, and sonolysis reactions are further destabilized by the high availability of this additional ionization energy. The addition of this ionization energy acts as a promoter to further drive or push the AOP reactions to produce more hydro peroxides, including hydrogen peroxide, within the AORC.
(55) To produce the ions, actively charged ion emitters, e.g. electrodes, are positioned near or on the digital reflector surfaces. It is desirable that these ion emitters are resistant to corrosion in the harsh AOP environment. The ion emitters can be either multipoint carbon fiber, or non-oxidizing metal such as high grade stainless steel, Inconel, or even titanium). The ion emitters may also be gold plated electrodes. The ion emitters are supplied with a voltage in the range of 1.5 K to 5 K volts, with a current not exceeding 1000 micro amps. Both positive and negatively charged ions are released, either from single or multiple locations within the sonic field.
(56) Secondary Advanced Oxidation Reaction Chamber
(57) In exemplary embodiments, a secondary and separate AORC can be positioned directly downstream from the wick structure, ultra sonic transducer(s), reflector assemblies, and other system components. The pretreated high humidity and ionically charged air flows from the wick structure assembly and into the secondary advanced oxidation reaction chamber. Here the very high humidity air goes through additional advanced oxidation processes.
(58) The secondary AORC consists of additional high surface area photocatalytic targets to further react with the high humidity air. This structure can consist of folded pleats with air passages, arrayed fins, or other suitable surfaces to provide maximum light conversion into AOP reactants. The key advantage to this secondary chamber addition is that the overall dimensions can be changed to accommodate higher amounts of AOP reactants (e.g. water). The design can include multiple light sources, larger cross sections of reactive surfaces, and a longer reaction chamber length. It can be more easily constructed to accommodate longer required reaction retention times, enabling a higher contaminant concentration treatment.
(59) Exemplary Embodiments
(60) The various components described above may be incorporated into a device for producing AOPs. Various embodiments of such devices are described herein. The devices are intended to be used as modular systems that can either be used singularly or in plurality (limited only by the specific application). The devices may be adapted to conform to multiple types of installations.
(61) In one embodiment of the invention, a device is provided for performing advanced oxidation reactions within an advanced oxidation reaction chamber using a Reflected Electro Mechanical Energy System. Although the device may be configured to produce a variety of AOP species, the design of this system is specifically configured to promote the production of the peroxide species hydrogen peroxide. This effect is achieved by actively collecting and concentrating water via a wick structure for the purpose of its conversion into hydrogen peroxide molecules. In this device, the wick structure is formed containing catalytic materials integral to its structure. Placement points for advanced oxidation photo catalytic surfaces are formed in situ, and in co-existence within the designed hydrating system. This unique placement of catalysts inside the hydrating structure and it associated crevices and pores further aids in the promotion of the advanced oxidation process's (AOP's). The in situ AOP reaction cycles formed are driven towards the increased production of hydrogen peroxide as they now occur within the same locations as the hydrating source, providing abundant water vapor to react with and subsequently form the hydro peroxide species. This entire device and process is accomplished using a multi-step system and approach.
(62) In one embodiment of the invention, shown in
(63) Referring now to
(64) A second air mass, which is typically lower flow than the first air mass, is also simultaneously flowed along the interior surface of the wick structure 11. Air moving along this inner air path 21 mixes with the AOPs produced, and helps to distribute them. Specifically, air flowing inside the AORC pulls and mixes the AOPs and water vapor released from the inner pores and surfaces of the wick structure into the second air mass.
(65) The second air mass is combined with the first air mass after passing through the AORC. The faster flowing first air mass (external to the wick structure) creates a low pressure zone, in essence a low or partial vacuum zone, as it passes the exit point of the second air mass (internal to the AORC). The creation of this low pressure zone actively pulls the second air mass stream into the first air mass stream, resulting in thorough and efficient mixing over a very short distance. After the first and second air masses have been combined, the combined air containing AOPs is released externally from the apparatus, and exists into ambient air (either duct or other space), so that the AOPs contained within the air mass can be further reacted and/or conveyed external to the AORC chamber for air and surface treatments.
(66) Notably, the unique features of the surface of the wick structure base material also enhance movement of air through the device. As shown in
(67) The device of
(68) In other embodiments, the apparatus may alternatively be mounted via an attached plate to facilitate treatment of air in many different types of installations, such as in an HVAC system (e.g., in an AC duct system). One such embodiment is shown in
(69) An air intake 906 receives air from the building environment, which includes pollutants, odors, mold, bacteria, virus, and other undesired chemicals. As this air passes through the duct 904 it is exposed to the apparatus 902, the light source, and the advanced oxidation processes, which will substantially clean and purify the air. This air, in combination with a portion of the advanced oxidation products created in the apparatus 902, is then driven through the remaining AC duct 904. The portion of the AOPs moving with the air continue to reduce the residual pollutants as they travel down the duct 904 with the air. Any remaining advanced oxidation products then exit 908 into the room, where they continue to quickly reduce any additional ambient pollutants encountered. Additionally, if a UV light source is used, germicidal UV light rays help destroy microorganisms, such as germs, molds, viruses, and bacteria passing through the AC duct 904. In this way, the advanced oxidation process apparatus 902 in this application, thereby cleans and purifies air for use in a building environment. Additionally, this apparatus will also kill microbes on surfaces external to the device, such as door knobs, duct surfaces, or other stainless steel surfaces. This feature is a key advantage over prior art devices.
(70) An example embodiment of a device for producing AOPs that is appropriate for mounting in a duct is shown in
(71) An alternative embodiment of a device for producing AOPs that is appropriate for mounting in a duct is shown in
(72) To facilitate ease of assembly and repair, one or more components of the devices of the instant invention may be manufactured as modular units. In
(73) An additional alternative embodiment of the devices for producing AOPs of the instant invention is shown in
(74) At the tip of the cone 83, the water exits the wick structure but stays in liquid form until exiting onto a sonic anvil 84 where it is then immediately hit with a narrow directed beam of high amplitude ultrasonic energy. The water is instantaneously vaporized by sonolysis cavitation, creating advanced oxidation reactions via the water itself, without the addition of a photo catalyst reactor or UV source.
(75) Air flow in this embodiment of the device is shown by arrows. Air travels vertically downward from the cone apex, transporting the vaporized water components that recently went through the sonolysis reactions back through the sonic beam. This air mass, moving from the cone apex 83 towards the ultrasonic transducer 84, creates a countercurrent plasma of air that is continually bombarded with ultrasonic energy, promoting the formation of AOPs until the air passes out of the sonic path and moves around and past the transducer. Here the sonolysis induced AOP reactants will continue to react with and also oxidize unwanted chemical compounds in the moving air mass. The countercurrent flow provides increased residence time for the reactions to take place and treatment to occur. Notably, because the same ambient air vapor is collected, and then re-released, there is no net effect on the overall humidity of the ambient environment, while still providing an effective air cleaning device.
(76) The embodiment of
(77) In an alternative embodiment, the apparatus may also be used to target and repel nuisance rodents and insects. In this embodiment, ultrasonic energy can be reflected and directed to external surfaces, with the specific intention of targeting the external environment of the ambient spaces containing the wick structure. More specifically, the inner duct space that the wick structure and the AORC are located in is targeted. This is made possible by modifying the digital reflector and a portion of its target points within the wick structure. As shown in
(78) The specific reflectors located on the main digital reflector array are angled and positioned to facilitate these sound waves exiting the wall. Releasing ultrasonic energy into these ambient duct spaces induces uncomfortable environmental conditions to household pests, including rodents and even susceptible insects. This simple modification in effect causes the AORC and wick structure system to also become a sonic pest deterrent system (as well as an advanced oxidation reactor). In one embodiment of this design the ultrasonic transducers can be configured to emit additional frequencies in the 24 through 60 kHz range. Ideally, varying these emitted frequencies and their amplitude throughout a randomly generated pattern. Doing this will cause the most discomfort to the nuisance pests, as this prevents environmental conditioning to a predictive sonic environment. The pests are prevented from becoming accustomed to either a single steady frequency or a simple patterned generation cycle of multiple frequencies at a constant amplitude.
(79) According to particular embodiments, the devices diagrammed in
(80) Method of Forming the Wick Structure
(81) Referring now to
(82) The wick structure may be formed from the following precursor materials: magnesium oxide (MgO), titanium tetraisopropoxide (TTIP, Ti{OCH(CH.sub.3).sub.2}.sub.4), cerium oxide (CeO.sub.2), and aluminum oxide (Al.sub.2O.sub.3). Catalytic enhancers including rhodium, silver, copper, zinc, platinum, nickel, erbium, yttrium, fluorine, sodium, ytterbium, boron, nitrogen, phosphorus, oxygen, thulium, silicon, niobium, sulfur, chromium, cobalt, vanadium, iron, manganese, tungsten, ruthenium, gold, palladium, cadmium, and bismuth, and combinations thereof may also be included with the precursor materials for increased catalytic effect of the final structure.
(83) In the first step of the process 61, the precursors, optionally including one or more catalytic enhancers, are combined with a solvent to form a reaction mixture. In one embodiment, the precursors are added to the reaction mixture in this ratio: 27 parts TTIP:74 parts MgO:4 parts cerium oxide:up to 1 part Al.sub.2O.sub.3. It is noted that the relative abundance of MgCO.sub.3 and TiO.sub.2 in the final wick structure matrix can be controlled by adjusting the initial mix ratio of the precursor materials. Changing the ratio of MgCO.sub.3 and TiO.sub.2 in the final wick structure will change the water absorbance vs. photo reactivity ratio in the final wick structure. The inventors of the instant application have found that a 3:1 ratio of MgCO.sub.3 to TiO.sub.2 in the final structure is optimal.
(84) The solvent used in the reaction mixture is preferably methanol, but ethanol and inorganic acid additions can also be used in conjunction with the methanol. Variations in the amounts of solvent and acid components may yield longer solution times, thereby affecting the final porosity of the wick structure. It is noted that the higher the rate of porosity in the final wick structure, the more effective the hydraulic attraction (higher water absorption), and the more surface area available for the photocatalytic reactions to occur. The inventors have found that a higher porosity is achieved by increasing the dissolution rate of the CO.sub.2 gas into the solvent. In the reaction mixture provided above, 48 parts of methanol would be provided with the 27 parts TTIP:74 parts MgO:4 parts cerium oxide:up to 1 part Al.sub.2O.sub.3.
(85) One method of controlling the dissolution of CO.sub.2 gas into the solvent in the reaction process is by controlling atmospheric pressure of the reaction chamber. As the reactor vessel pressure increases, the solubility of the methanol increases (Henry's law). At atmospheric pressure methanol already has five times the CO.sub.2 solubility as compared to water's CO.sub.2 solubility. Secondarily, this process can be aided further by altering the inherent solubility of the methanol itself. Prior to adding the methanol to the reactor, to increase its solubility further, it can actually be chemically altered with a small addition of aluminum oxide (Al.sub.2O.sub.3). A 0.05% by weight addition of aluminum oxide will dramatically increase the methanol's solubility to CO.sub.2 (doing this additional step will actually increase the methanol's CO.sub.2 solubility by nearly 10%). Alternatively, SiO.sub.2 may be added at the same rate. However, Al.sub.2O.sub.3 is preferred, as addition of this material results in a higher porosity (as well as also requiring less external energy, due to the lower gas pressures for the equivalent solubility). The use of Al.sub.2O.sub.3 also has the benefit of aiding in increasing the wick structure's inherent wall strength.
(86) The reaction mixture is provided in a modified gas atmosphere (MGA) reaction chamber. The reaction chamber comprises an internal mixing mechanism to facilitate the continual mixing of components during the reaction process. Mixing may be achieved using devices known to those skilled in the art, such as a paddle blade mixer. The mixing is preferably performed at a speed not exceeding 450 RPM, in order to reduce wall splattering and to ensure optimal mixing of all constituents throughout the reaction. The reaction chamber must also have a suitable means of detecting and displaying both pressure and temperature, as well as gas addition ports, flushing ports, a secondary process component addition port (pressure isolated), and a viewing port. A high pressure relief valve is also recommended.
(87) After the reaction mixture is placed in the reaction chamber, oxygen is purged from the chamber using CO.sub.2 gas, to provide a reaction atmosphere of pure CO.sub.2 gas. Mixing is then initiated, in step 62. The internal pressure of the reactor is raised to a minimum pressure of 45 PSI, while the reactants are simultaneously heated to a temperature of 140 F. (60 C.). Pressure release steps are often required to maintain a maximum pressure of 45 PSI, until the final reaction temperature is reached and stabilized. The reaction pressure, temperature and mixing is maintained for a minimum of four hours, and results in the formation of a flowing slurry. During the reaction time, the MgO is transformed to MgCO.sub.3, and the titanium tetraisopropoxide is simultaneously transformed into anatase titanium dioxide (TiO.sub.2). The MgCO.sub.3 and the TiO.sub.2 comprise a reacted matrix within the slurry with cerium oxide dispersed throughout (with small amount of Al.sub.2O.sub.3, added in methanol step and at precursor mixing)
(88) In step 63, after the reaction phase is completed, up to an additional 3.75 parts aluminum (III) oxide is optionally added to and fully mixed into the slurry. This step of adding aluminum (III) oxide specifically after the reactions producing magnesium carbonate and titanium dioxide have occurred and while the base material is still in a flowing slurry results in a more rigid final wick structure. The addition of aluminum (III) oxide at this stage in the process is advantageous when the final wick structure matrix is designated for mold casting because the addition of aluminum (III) oxide at this stage of production yields a material which is mold stable and releasable. In embodiments wherein the final wick structure will not be shaped via mold casting, the step of adding aluminum (III) oxide can be omitted, further increasing final porosity per gram of the wick base material.
(89) Additionally and independently, in step 64, one or more secondary photocatalytic reaction enhancers, selected from rhodium, silver, copper, zinc, platinum, nickel, erbium, yttrium, fluorine, sodium, ytterbium, boron, nitrogen, phosphorus, oxygen, thulium, silicon, niobium, sulfur, chromium, cobalt, vanadium, iron, manganese, tungsten, ruthenium, gold, palladium, cadmium, and bismuth, and combinations thereof can be added to the slurry during this stage of production, if desired. These enhancers should be added through the material additives port.
(90) After the optional addition of aluminum (III) oxide, SiO.sub.2, and/or secondary catalytic enhancers, the process heat is discontinued, and the CO.sub.2 reactant pressure is raised to 200 PSI. The slurry is mixed for an additional 10 minutes, further increasing the amount of dissolved CO.sub.2 in the slurry. After the additional 10 minutes, the mixing is discontinued and the chamber is depressurized through a series of stepped pressure releases. Specifically, the pressure is reduced in increments of 10 PSI at intervals which range from 5 minutes to 2 hours, until the pressure of the chamber is reduced to a final pressure of 15 PSI. The optimal length of the pressure reduction intervals varies depending on the final mix proportions of the reaction mixture. This pressure is then maintained for the remainder of this phase of production, referred to herein as the congealing phase.
(91) In step 65, the congealing phase, the initial conversion of the slurry to a solid phase begins. This stage of production may take up to 5 days, and is halted at first indications of solidification. During this time, the reaction chamber is kept closed and no mixing is performed. Further, the pure CO.sub.2 atmosphere of the vessel is maintained, and the pressure is kept at a stable 15 PSI. As long as ambient temperatures are maintained at approximately 70 to 80 F. (21 to 27 C.), no external heat is applied.
(92) The pressure reduction steps described above produce successive micro off gassing events (effervescence) of the CO.sub.2 gas into the wick structure slurry base material during the congealing phase. This stepped effervescence event increases the internal surface area of the solidifying matrix. If the solidifying process is delayed, a re-pressurization step and repeat of this stepped process is performed.
(93) Once the material begins to congeal it can then be cast poured into molds of desired geometries, if desired, according to step 66. Ideally this step is also performed under a 15 PSI CO.sub.2 atmosphere.
(94) Once the slurry has solidified, the chamber is finally fully depressurized and brought to ambient air conditions. It is then removed from the reactor vessel, either present in molds or in granular form.
(95) The next step 67 is the drying phase, which comprises two stages. The preliminary drying phase is referred to herein as the low temperature drying process. In this process, the material that is either cast within the molds (the high Al.sub.2O.sub.3 product), or in unmolded granular form (with the very low Al.sub.2O.sub.3) and is heated to 160 F. (71 C.) for 36 hours. This step drives off any remaining solvent and further hardens the entire mass.
(96) In exemplary embodiments, the material may additionally be soaked in deionized water (Millipore prepared) to completely hydrolyze any remaining titanium IV into anatase titanium dioxide. However, performance of this additional step will increase preparation costs due to longer drying times required to slowly expunge excess water, and will also result in diminished pore sizes in the internal structures prior to calcination.
(97) After the initial low temperature drying process, a final calcination step (high temperature drying step) is performed to fully activate the components of the wick structure. The calcination step serves several important functions. First, this step removes any remaining inorganic material from the internal wick structures (crevices and pores) thereby greatly increasing the final porosity and water absorbance of the material (up to 50% greater surface area). This step is also essential to fully activate the formed TiO.sub.2, ensuring anatase crystallization, and to prepare the surface of the TiO.sub.2 crystals for eventual photo activation. This calcination step further binds the cerium oxide (CeO.sub.2), and aluminum oxide (Al.sub.2O.sub.3) into a hard ceramic matrix, greatly increasing the overall strength of the wick structure.
(98) The calcination step is performed by slowly increasing the temperature of the wick structure from ambient temperature to 650 F. (343 C.) over the course of 8 hours. It is essential that the initial temperature ramp up to 650 F. be performed very slowly. Proceeding too quickly at this step will cause the materials to expand too rapidly (especially if there is any fluid, i.e. water left over from the Titania IV hydration reaction additions, etc.) and will cause physical damage to the materials and the pore structures (i.e. micro steam induced explosions cause by trapped water in the tiny pores not yet fully opened by the calcination process). Thus, it is highly desirable to level off the ramp temperature increase and hold the temperature at 180 F. (82 C.) for 3 hours before continuing with the original cure ramp rate. Once the temperature is at 650 F. (343 C.), the temperature is maintained for 12 hours to fully activate the system components. A higher calcination temperature may be used to help reduce process time. However, the temperature should never exceed 1000 F. (538 C.) at any time during this process. At temperatures above 1000 F. (538 C.), the anatase crystals will be converted into less desirable rutile crystals. Also, a 60 minute hold time is the minimum required to achieve the desired calcination effect to the MgCO.sub.3 in the wick structure.
(99) The inventors of the instant application have performed the calcination process in a kiln fired at 20% excess oxygen, and alternatively with material being purged in a kiln with a 100% nitrogen atmosphere. Activation occurred in both tests, and produced the desired properties in the final wick structure. However, it was found that the 20% excess oxygen environment provided a better overall result for the desired hybrid performance (hydration enhancement and catalyst activation).
(100) Once the calcination step completed, temperatures are ramped down at 100 F. (38 C.) per hour until ambient temperature is reached. After the wick structure has cooled, the dried material is removed either as fully activated granules, or is released/removed from the molds as ready to use wick structure.
(101) Summary
(102) The advanced oxidation processes, as provided by alternative embodiments of the present invention in view of the discussion above, consist of reactions with any combination of hydroxyl radicals, super oxide ions, hydro peroxides, ozonide ions, and hydroxides, and other such advanced oxidation products, that revert back to oxygen and hydrogen after the oxidation of the pollutants. Additionally, in certain alternative embodiments, germicidal UV light rays can additionally help destroy microorganisms, such as germs, molds, viruses, and bacteria. In this way, the advanced oxidation processes, and optionally in combination with any germicidal U.V. light rays, clean and purify an environment by reducing microorganisms, odors, and other undesirable chemicals in the environment. The advanced oxidation processes, as provided by the alternative embodiments of the present invention, can be very useful in many different applications, as should be obvious to those of ordinary skill in the art in view of the discussion above.
(103) While there has been illustrated and described what are presently considered to be the preferred embodiments of the present invention, it will be understood by those of ordinary skill in the art that various other modifications may be made, and equivalents may be substituted, without departing from the true scope of the present invention. Additionally, many modifications may be made to adapt a particular situation to the teachings of the present invention without departing from the central inventive concept described herein. Furthermore, an embodiment of the present invention may not include all of the features described above. Therefore, it is intended that the present invention not be limited to the particular embodiments disclosed, but that the invention include all embodiments falling within the scope of the appended claims.