WO2024261675A1

WO2024261675A1 - Singlet oxygen producing device

Info

Publication number: WO2024261675A1
Application number: PCT/IB2024/056013
Authority: WO
Inventors: Daniel Edward Gruenberg
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-06-23
Filing date: 2024-06-20
Publication date: 2024-12-26
Anticipated expiration: 2025-12-23

Abstract

The present invention discloses a singlet oxygen producing device comprising: a pressure vessel; a means for introducing an oxygen-containing gas into the pressure vessel; a magnetic source configured to generate at least a first magnetic field and a second magnetic field wherein the direction of the first magnetic field is oriented substantially opposite to the second magnetic field; a light source configured to emit a light with a wavelength in a range of 200-300 nm; and a metallic catalyst containing molybdenum with a surface roughness of less than 100 nm, wherein the device is configured such that the oxygen-containing gas substantially passes through the resulting opposing magnetic field created by the first and second magnetic field prior to receiving the light emitted from the light source.

Description

SINGLET OXYGEN PRODUCING DEVICE

FIELD OF INVENTION

[0001] The present invention is in the technical field of engineering, particularly reactive oxygen generation. More particularly, the present invention is in the technical field of high concentration gas phase singlet oxygen generation for use in water treatment systems as an oxidant with unique beneficial properties compared to alternatives such as ozone.

BACKGROUND OF THE INVENTION

[0002] Reactive Oxygen Species (ROS) produced from atmospheric air are desirable for certain water treatment applications since they don’t require any chemical costs other than the electricity required to produce them and eliminate complicated logistics and worker safety issues required for alternative methods. Production of high concentration gas phase singlet oxygen has not been reported previously. Ozone, which is produced from atmospheric oxygen either via UV activation using wavelengths less than 200nm, or alternatively by applying a high voltage potential via corona discharge devices, is widely used in various water treatment processes, but it has many draw backs compared to singlet oxygen such as short half-life and low solubility at elevated pH and temperatures. The ability to produce singlet oxygen from atmospheric triplet oxygen would open novel applications for treatment of water, especially cooling tower water where singlet oxygen exhibits biocidal, anti-scaling and anti-corrosion effects, with the ability to eliminate chemicals in cooling water treatment systems. The anti-viral and anti-bacterial effects of singlet oxygen are well documented, but its use has been hindered by the lack of cost-effective means of producing it in the gas phase without the need for aqueous chemistry.

[0003] While various methods for the production of aqueous phase singlet oxygen exist, these all require various chemical inputs and rather complicated or inefficient mechanisms for their production. Irradiation of oxygen gas in the presence of an organic dye as a sensitizer, such as rose bengal, methylene blue, or porphyrins, which are all a photochemical methods, results in its production. Large steady state concentrations of singlet oxygen are reported from the reaction of triplet excited state pyruvic acid with dissolved oxygen in water. Singlet oxygen can also be in non-photochemical, preparative chemical procedures. One chemical method involves the decomposition of triethylsilyl hydrotrioxide generated in situ from triethylsilane and ozone.

(C₂H₅)₃SiH + O₃ (C₂H₅)₃SIOOOH (C₂H₅)₃SiOH + O₂(¹A_g)

Another method uses the aqueous reaction of hydrogen peroxide with sodium hypochlorite:

H₂O₂ + NaOCl O₂(¹A_g) + NaCl + H₂O

A third method liberates singlet oxygen via phosphite ozonides, which are, in turn, generated in situ such as triphenyl phosphite ozonide. Phosphite ozonides will decompose to give singlet oxygen:

(ROM’ + O₃ ( RO) 4’03

(ROM’O . -> (RO)₃PO + O₂(⁵ A_g)

SUMMARY OF THE INVENTION

[0004] The present invention is a reactor that can produce activated singlet state gaseous oxygen from atmospheric ground state triplet oxygen.

[0005] Although there does presently exist methods to produce singlet oxygen in the gas phase, this has never been done previously with atmospheric ground state triplet oxygen as the substrate. This will open new applications of this highly beneficial reaction oxygen species which are capable of producing hydroxyl radicals when dissolved in water and thus providing for a novel advanced oxidation process (AOP) which are characterized by the production of hydroxyl radicals in water.

[0006] In the first embodiment, the present invention provides a singlet oxygen producing device comprising: a pressure vessel; a means for introducing an oxygen -containing gas into the pressure vessel; a magnetic source configured to generate at least a first magnetic field and a second magnetic field wherein the direction of the first magnetic field is oriented substantially opposite to the second magnetic field; a light source configured to emit a light with a wavelength in a range of 200-300 nm; and a metallic catalyst containing molybdenum with a surface roughness of less than 100 nm, wherein the device is configured such that the oxygen -containing gas substantially passes through the resulting opposing magnetic field created by the first and second magnetic field prior to receiving the light emitted from the light source.

[0007] Preferably, the metallic catalyst is a nano-catalyst with an ultra-smooth nano finish.

[0008] According to the embodiment, the first and second magnetic fields with the direction substantially opposite to each other generates the opposing magnetic field so as to apply torque on the electron in the oxygen-containing gas. When used in combination with the light source, the device is configured to provide sufficient force and energy on the electron in the gas to allow the formation of singlet oxygen.

[0009] Additionally, the metallic catalyst facilitates the formation by temporarily binding the oxygen molecule to the catalyst surface allowing efficient application of torque on the electron.

[0010] In another embodiment of the present invention, the magnetic field has a magnetic strength of at least 500 gauss, measured at all points where gas passes the first and second magnetic field.

[0011] Preferably, the metallic catalyst comprises a material selected from the group consisting of at least one of the following alloys of stainless steel: 316, 316L, 310MoLN, 316H, 316Ti, 316Cb, 316N, 316LN, 317, 317L, 317LM, 317LMN, 317LN, 2205, 2304, 255, 2507, 422, 434, 436, 440A, 440B, 440C, 444, 904L, Alloy 20, XM-2, XM-17, XM-18, XM-19, XM-27, XM-33, XM- 34.

[0012] With said embodiment, the selected stainless steels have bonding properties that hold dioxygen molecules on the surface of the catalyst which makes it easier for the magnetic field to apply a torque to the electrons to assist in reversing the spin for forming singlet oxygen.

[0013] More preferably, the metallic catalyst contains about 2-3% of molybdenum and polished to a final finish with a surface roughness of less than 50 nm.

[0014] In another embodiment, the number of photons contained in the emitted light is at least as great as a number of ground state oxygen molecules in the oxygen-containing gas. Thus, the number of photons and the ground states oxygen molecule are sufficient to raise the energy level of electron for forming singlet oxygen.

[0015] According to another embodiment, the magnetic source comprises a Samarium-cobalt magnet. [0016] Preferably, the magnetic source comprises a plurality of ring magnets allowing the oxygencontaining gas to pass therethrough.

[0017] The magnet in the embodiment is capable of operating at increased temperatures with varying ability to generate a magnetic field oriented substantially opposite to another field without demagnetizing. Moreover, the magnet will have a prolonged lifespan in used in the device.

[0018] In another aspect, the oxygen-containing gas is further subjected to a third magnetic field and a fourth magnetic field prior to exiting the pressure vessel, the third and the fourth magnetic fields having an opposite polarity to the first and the second magnetic fields.

[0019] Preferably, the oxygen-containing gas substantially passes through another resulting opposing magnetic field created by the third and fourth magnetic fields.

[0020] More preferably, the oxygen-containing gas substantially passes the resulting opposing magnetic field prior to leaving the pressure vessel.

[0021] With the above embodiments, the oxygen-containing gas will be stabilized so as to increase the half-life of the singlet oxygen formed.

[0022] According to another embodiment, the device further comprises a filter configured to remove particulates from the oxygen-containing gas prior to being subjected to the magnetic fields.

[0023] Preferably, the filter comprises a medium efficiency filter and a High-efficiency particulate absorbing (HEPA) or Ultra-low Penetration Air (ULPA).

[0024] With the configuration of the filter, particulates are substantially removed from the oxygencontaining gas which increases the exposure of the gas the light while reducing possible contamination to the catalyst and in the device.

[0025] In addition, the oxygen-containing gas is further supplied to micro/nano bubble generator.

[0026] Preferably, the oxygen-containing gas with the singlet oxygen is supplied to the micro/nano bubble generator after leaving the pressure vessel.

[0027] In another aspect, the singlet oxygen produced from the device of any combination of the foregoing embodiments which is used for water treatment.

[0028] In yet another aspect, the present invention provides a method of producing activated singlet oxygen from atmospheric ground state triplet oxygen as a substrate through a device according to any one of the above-mentioned embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Fig. 1 a flow-diagram of steps of a method in accordance with an embodiment of the present invention.

[0030] Fig. 2 is a perspective view of the singlet oxygen producing device in accordance with a preferred embodiment.

[0031] Fig. 3 is a side view of the magnet source in accordance with a preferred embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0032] It is to be understood that the following detailed description will be directed to embodiments, provided as examples for illustrating the concept of the present invention only. The present invention is in fact not limited to particular embodiments described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of this invention will be limited only by the appended claims.

[0033] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0034] It must be noted that as used herein and in the appended claims, the singular forms “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.

[0035] The term “about” when used before a numerical designation, e.g., dimensions, time, amount, and such other, including a range, indicates approximations which may vary by ( + ) or ( - ) 10 %, 5 % or 1 %, or any sub-range or sub-value there between.

[0036] “Comprising” or “comprises” is intended to mean that the compositions and processes include the recited elements, but not excluding others. “Consisting essentially of’ when used to define compositions and methods, shall mean excluding other elements of any essential significance to the combination for the stated purpose. Thus, a process or product consisting essentially of the elements as defined herein would not exclude other materials or steps that do not materially affect the basic and novel characteristic(s) of the claimed invention. “Consisting of’ shall mean excluding more than trace elements of other ingredients and substantial steps. Embodiments defined by each of these transition terms are within the scope of this invention.

[0037] Referring now to the invention in more detail, in Fig. 1 there is shown a flow diagram of a method to produce gas phase singlet oxygen 100 from atmospheric ground state triplet oxygen. According to an embodiment, the method for produce gas phase singlet oxygen 100 comprises introducing an oxygen-containing gas 110, preferably atmospheric air, into a device for producing singlet oxygen. Preferably, the gas used in this process cannot contain any particles that could contaminate the catalyst or block the UVC source, so the method further comprises the step of filtering the gas 120. Specifically, the system of filters used in step 120 comprises a pre-filter, a medium efficiency filter and a HEPA or ULPA filter to remove >99.8% of particulate matter greater than 0.1 micrometers in diameter. Next, the method comprises pressurizing the gas 130. Specifically, a blower or compressor is used to pressurize the now clean gas without particles so that it can then be passed through a magnet source which will be further described below.

[0038] In an embodiment, the method comprises the step of passing the gas through magnetic fields 140. The magnet source used to generate the magnetic fields is designed to pass the ground state triplet dioxygen molecule which is unique in that it is actually a double radical with two single electrons occupying each P-orbital (Pz and Py) so it is a paramagnetic gas. In order to create singlet oxygen from ground state triplet dioxygen gas, one electron must move so that one P- orbital contains both electrons and the other is completely empty. In order for this to occur, due to the Pauli exclusion principle which disallows electrons of the same spin from occupying the same orbital, one electron must flip its spin when it moves to the other P-orbital.

[0039] Secondly, the method comprises the step of applying energy 150 to the oxygen-containing gas because the electron needs to absorb sufficient energy to move so that both electrons occupy the same P-orbital. The magnet using opposing magnetic fields applies a torque to one of the electrons and the molybdenum containing ferrous steel surface helps by temporarily binding the oxygen molecule to the catalyst surface, allowing efficient application of torque on the electron and an energy source provides sufficient energy to complete the formation of singlet oxygen. The opposing magnetic field used requires a field strength of approximately more than 500 gauss, measured where the gas passes. Alternatively, the magnetic strength can also be in the range of 200-1,000 Gauss. The choice of magnetic material is important here because this reactor operates at increased temperatures and magnets have varying ability to oppose an opposing field without demagnetizing. The best magnetic material to use for this purpose is a Samarium Cobalt magnet. Alternatively, an electromagnet could also be used but this would utilize more electrical power and be less reliable.

[0040] In step 150, the energy is applied to the gas by means of a light source. Preferably, the light source is configured to emit a light with a wavelength in a range of 200-300 nm. More preferably, the light source is UVC. The UVC source could be a low-pressure mercury, amalgam, or LED source. The amount of UV energy is calculated according to the amount of air flow and the additional energy required per mole of molecular atmospheric dioxygen to produce singlet oxygen. The minimum photon energy required is 94.29 kJ/mol of singlet oxygen. For a flow rate of atmospheric air at 60LPM flow rate, at 30°C and 50% humidity, a low-pressure mercury lamp of at least 80 W will provide sufficient photon energy required for this step.

[0041] Thirdly, the step 150 may further include exposing the oxy gen-containing gas to a metallic catalyst. The inventors have found that the use of nano-polished ferrous stainless steels containing molybdenum will greatly improve the efficiency of the process. A common stainless steel such as 316L which contains about 2-3% of molybdenum when polished to a final finish of Ra<0.05pm obtains special bonding properties that hold the dioxygen molecules on the surface which makes it easier for the magnetic field to apply a torque to the electrons to assist in reversing the spin so both can occupy the same orbital.

[0042] Fig. 2 is a perspective view of the singlet oxygen producing device 1 in accordance with a preferred embodiment of the invention. As shown in the figure, an oxygen-containing gas 2, preferably atmospheric air, is introduced into a filtration system 10 comprising a series of filters finally ending in eliminating >99.8% of particulate matter larger than 0.1 pm prior to entering the compressor 20 or blower. The compressor 20 is capable of creating between 3 and 10m water column of pressure before entering a pressure vessel 30 via an inlet 31. Opposing magnetic fields are created by a magnetic source 40, specifically a plurality of magnets 41, 42, with the strength of more than 500 gauss when measured where the gas passes. Alternatively, the magnetic strength can also be in the range of between about 200 and 1,000 gauss. A metallic catalyst 50, preferably a nano-catalyst, is consisting of nano-polished 316 stainless steel having a surface roughness (Ra) of less than 100 nm. Preferably, the surface roughness is <0.05 pm (<50nm). The pressure vessel 30 contains a light source 60 which is configured to emit UVC light of between 200-300nm in wavelength. Finally, gas phase singlet oxygen exits the pressure vessel 30 via an outlet 32 where it can be moved to its point of use.

[0043] In a preferred embodiment, the oxygen-containing gas with the singlet oxygen is further supplied to a micro/nano bubble generator (not shown) which is mainly utilized for water treatment.

[0044] In more detail, still referring to the invention of Fig. 2, in a specific embodiment, the pressure vessel 30 is a reactor tube made of aluminum to allow efficient heat to transfer out of the reactor.

[0045] With regard to the metallic catalyst 50, the nano-polished 316L or other stainless alloys containing at least 2-3% molybdenum is difficult to polish if less than 200 microns in thickness. A 200 micron thickness 10k finished polishing must be mechanically polished as electropolishing does not give the desired catalytic effect, likely due to the fact that the small grain size resulting from the mechanical polishing process being critical to its function. A 316L stainless steel sheet of 200 microns in thickness is polished starting with 400 grit sand paper, and followed by 800, 1200, 1600 and finally progressively finer buffing compounds, until a nano-diamond finish with an Ra<0.05 microns (<50nm) is obtained.

[0046] In more detail, still referring to the invention of Fig. 2, the light source 60 or the UVC source needs sufficient energy to supply high energy photons with a wavelength of between about 200 and 300 nanometers supplying at least 94.29 kJ/mol of diatomic oxygen flowing through the reactor.

[0047] Fig. 3 shows a side view of the magnetic source 40 and the configuration of a magnet set 41. As shown in Fig. 3, the magnet set 41 comprises the first magnet 41a and the second magnet 41b each having a ring shape. The first magnet 41a is arranged to have the same polarity facing the second magnet 41b. Since the first magnetic field and the second magnetic field are produced by the first magnet 41a and second magnet 41b, the arrangement of the magnets creates the opposing magnetic field 43 where the oxygen-containing gas 2 substantially passes through. Further, the oxygen-containing gas 2 then receives the light emitted from the light source 60 arranged after the magnetic source 40 relative to the traveling direction of the gas 2. Additionally, the oxygencontaining gas 2 is exposed to the surface of the metallic catalyst 50 disposed near the magnetic source 40.

[0048] Preferably, as shown in Fig. 2, another of magnet set 42 is disposed near the end of the pressure vessel 30 with the similar configuration to the magnet set 41 in Fig. 3. This magnet set 42 is configured generate the third and the fourth magnetic fields to stabilize and increase the half-life of the singlet oxygen formed in the oxy gen-containing gas 2 prior to exiting the pressure vessel 30 for further use.

[0049] The process to create singlet oxygen, in contrast to other ROS such as ozone, works better at higher temperatures. A reactor operating at 60°C works approximately twice as efficiently than one operating at 30°C. This is a very surprising result. Actual operating temperatures are limited by materials used in the reactors, but 60-70°C gives good operational efficiency while still being within the temperature range for wire insulation, plastic electrical connectors, etc.

[0050] The light source can be any type such as LED, excimers, etc. and the scope of this invention shall not be limited by the UVC source used. The magnetic source used is ideally provided as a samarium cobalt type permanent magnet but in practice electromagnets or other types of permanent magnets can be used.

[0051] The advantages of the present invention include, without limitation, a novel type of AOP which works at higher temperatures and pH compared to ozone, and a method of providing commercial quantities of singlet oxygen for use in water treatment processes without the use of chemicals and require only atmospheric diatomic oxygen and electricity as inputs.

[0052] In broad embodiment, the present invention is used to produce singlet oxygen for cooling water treatment, pool water treatment, drinking water treatment, hydroponics or irrigation water treatment and for the treatment of water used in aquaculture or aquatic plants and animals.

[0053] While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention.

Claims

1. A singlet oxygen producing device comprising: a pressure vessel; a means for introducing an oxy gen-containing gas into the pressure vessel; a magnetic source configured to generate at least a first magnetic field and a second magnetic field wherein the direction of the first magnetic field is oriented substantially opposite to the second magnetic field; a light source configured to emit a light with a wavelength in a range of 200-300 nm; and a metallic catalyst containing molybdenum with a surface roughness of less than 100 nm, wherein the device is configured such that the oxygen-containing gas substantially passes through the resulting opposing magnetic field created by the first and second magnetic field prior to receiving the light emitted from the light source.

2. The device of claim 1, wherein the magnetic field has a magnetic strength of at least 500 gauss, measured at all points where gas passes the first and second magnetic field.

3. The device of claim 1 or 2, wherein the metallic catalyst comprises material selected from the group consisting of at least one of the following alloys of stainless steel: 316, 316L, 310MoLN, 316H, 316Ti, 316Cb, 316N, 316LN, 317, 317L, 317LM, 317LMN, 317LN, 2205, 2304, 255, 2507, 422, 434, 436, 440A, 440B, 440C, 444, 904L, Alloy 20, XM-2, XM-17, XM-18, XM-19, XM-27, XM-33, XM-34.

4. The device of any one of claims 1 to 3, wherein the number of photons contained in the emitted light is at least as great as a number of ground state oxygen molecules in the oxygencontaining gas.

5. The device of any one of claims 1 to 4, wherein the magnetic source comprises a Samariumcobalt magnet.

6. The device of any one of claims 1 to 5, wherein the magnetic source comprises a plurality of ring magnets allowing the oxygen-containing gas to pass therethrough.

7. The device of any one of claims 1 to 6, wherein the oxygen-containing gas is further subjected to a third magnetic field and a fourth magnetic field prior to exiting the pressure vessel, the third and the fourth magnetic fields having an opposite polarity to the first and the second magnetic fields.

8. The device of any one of claims 1 to 7, further comprising a filter configured to remove particulates from the oxygen-containing gas prior to being subjected to the magnetic fields.

9. The device of any one of claims 1 to 8, wherein the oxygen-containing gas is further supplied to a micro/nano bubble generator.

10. The device of any one of claims 1 to 9, wherein a singlet oxygen produced from the device is used for water treatment.