Mobile system and method for microwave-assisted surface decontamination

Abstract

A mobile decontamination system and microwave-assisted decontamination method for decontaminating various contaminated surfaces located outside the system are disclosed. The system and method treat the surfaces with a non-toxic chemical formulation followed by brief exposure to microwave irradiation to achieve at least a 6-log reduction in biological contaminants, including viruses and spores of B. anthracis, B. thuringiensis, and P. roqueforti. The formulation comprises percarbonate and a surfactant in water.

Description

Related Applications

[0001] This application is related to and claims the benefit of U.S. Provisional Application No. 63 / 032,726, filed June 1, 2020, and entitled "Microwave-Assisted Method and System for Surface Decontamination." Federally Funded Research and Development

[0002] Portions of this disclosure were made with U.S. Government support under Contract No. HSHQDC-14-C-00050 awarded by the U.S. Department of Homeland Security. The U.S. Government may have certain rights in this disclosure. [Technical Field]

[0003] This disclosure relates to methods and systems for decontaminating various contaminated surfaces, both in enclosed structures and large areas. Specifically, the systems and methods involve treating the surfaces with a non-hazardous chemical formulation, followed by brief exposure to radio frequency radiation (microwaves). [Background technology]

[0004] A recent report from the National Institutes of Health (NIH) and its partners (N. van Doremalen et al., 2020) indicates that the virus that causes coronavirus disease 2019 (COVID-19) is stable in aerosols and on surfaces for hours to days. SARS-CoV-2 was detectable in aerosols for up to 3 hours, on copper for up to 4 hours, on cardboard for up to 24 hours, and on plastic and stainless steel for up to 2–3 days. These results provide important information about the stability of SARS-CoV-2, the virus that causes COVID-19 disease, and suggest that people may become infected with the virus through the air or after contact with contaminated objects. On cardboard, the half-life of SARS-CoV-2 was longer than that of SARS-CoV-1. The estimated half-life of SARS-CoV-2 was approximately 5.6 hours on stainless steel and approximately 6.8 hours on plastic. Rapid and effective surface decontamination methods are needed to limit the spread of COVID-19.

[0005] The commercial aviation industry lost billions of dollars in revenue during the SARS (Severe Acute Respiratory Syndrome) outbreak. The only approved method for decontaminating commercial aircraft involves personnel wearing protective suits with respirators manually wiping down all surfaces on board using a liquid disinfectant (such as diluted bleach). This is a laborious and time-consuming process, making it impractical when large numbers of aircraft require decontamination. Other market segments, such as the travel and hospitality market, have similar needs for treating contamination on cruise ships, buses, trains, and other shared environments. Decontamination of military aircraft using high-temperature, humid air has been tested. Reports suggest that destruction of spores using high-temperature, high-humidity levels required treatment for approximately three to four days. This approach also damages critical systems onboard aircraft. In a pandemic or biological attack situation, there is a significant risk of contamination of aircraft or airborne landing point (APOD) sites. Traditional oxidizing decontaminants can embrittle the aircraft's aluminum or damage sensitive equipment at APODs.

[0006] Turning to the healthcare market, cleaning and disinfection functions are routine throughout the healthcare industry. Patient rooms, operating rooms, and isolation rooms for highly infectious patients require regular disinfection, or in some cases, complete sterilization. Target organisms are typically bacteria, bacterial spores, and viruses, not mold. Ventilation systems may also require regular disinfection. Decontamination of entire buildings is costly and difficult. The Bio-Response Operational Testing and Evaluation (BOTE) project was a multi-agency effort designed to test and evaluate, at the scale of a medium-sized building, the response to an initial public health and law enforcement investigation of an anthrax spore release through environmental remediation. First responders also face challenges with decontamination or disinfection. Decontamination of ambulances transporting patients with infectious diseases such as Ebola virus disease and patients infected with novel coronaviruses (such as COVID-19 patients) is also challenging because ambulances must be repaired before they can return to service.

[0007] Fumigants have been used to decontaminate surfaces exposed to agents released in enclosed structures, such as during the 2001 Amerithrax mail attack. A key challenge during the decontamination of the U.S. Hart Senate Building was the need to maintain a minimum temperature of 70°F and a minimum relative humidity of 65% for the decontamination agent, chlorine dioxide (CD), to ensure stable and effective use. Outside these conditions, CD readily decomposes to produce chlorine. Chlorine is highly reactive and can damage surfaces. Furthermore, CD is toxic to humans. CD concentrations of approximately 700 ppm were used for many hours. The OSHA Permissible Exposure Limit (PEL) for CD is 0.1 ppm, the 15-minute Short-Term Exposure Limit (STEL) is 0.25 ppm, and the NIOSH Immediate Damage to Life and Health (IDLH) level is 5 ppm. Significant damage to building surfaces was reported as a result of the cleanup.

[0008] The use of other fumigants is also problematic. For example, vaporized hydrogen peroxide (VHP) at a concentration of 200 ppm is somewhat less toxic than CD, which has a PEL of 1 ppm, a STEL of 2 ppm, and an IDLH of 75 ppm. Other examples of fumigants for decontamination are methyl bromide and formaldehyde. Methyl bromide is a well-known and highly potent greenhouse gas, requiring complete coverage of structures to minimize atmospheric release. Formaldehyde has only been used in limited applications, such as decontaminating small rooms and laboratory equipment. Formaldehyde is a known carcinogen and is toxic (PEL of 0.75 ppm, STEL of 2 ppm), typically leaving a solid polymeric residue that must be removed from all surfaces to prevent long-term gas release. Fumigants are also not useful for surface decontamination in widespread outdoor release scenarios.

[0009] To decontaminate large-scale (outdoor) surfaces, oxidation has been attempted to inactivate biothreat agents on surfaces. Oxidizing agents include at least one of the following: hydroxyl radicals, gaseous oxygen, ozone, hydrogen peroxide, hypochlorites (bleaching agents such as sodium hypochlorite and calcium hypochlorite), and chlorine, which can be generated on-site if necessary. However, these chemicals damage surfaces and are generally toxic to humans. Due to these undesirable side effects, for example, the U.S. Department of Defense has attempted biological decontamination of ground vehicles using hot, soapy water and decontaminating aircraft interiors using a combination of hot air and high humidity for extended periods. These approaches are not effective at destroying biological contaminants. Furthermore, if biothreat agents are dispersed over a wide area, hazmat response teams find it difficult to decontaminate their equipment and vehicles.

[0010] Decontamination of large areas of surfaces has also been attempted by first exposing them to chemicals such as sodium hypochlorite (bleach) and then to microwave radiation to generate highly reactive oxidizing species that kill biological agents. For example, Raytheon and Los Alamos National Laboratory demonstrated a 6-log kill (reduction, >99.999%) of Bacillus anthracis (Stern) spores on complex surfaces by spraying the surface with diluted household bleach (0.025% sodium hypochlorite) or carbon black and then activating the treated surface for approximately 5 to 120 seconds using 95 GHz irradiation. Greater than a 6-log reduction in anthrax was observed with exposure times greater than 5 seconds. In this hybrid approach, the chemical used prior to exposure to radiofrequency radiation, such as microwaves, can be considered a directed energy enhancer ("DEE"). When exposed to RF radiation, the DEE chemical possesses biocidal properties and generates oxygen-containing radicals that kill biological contaminants. These reactive species can be generated continuously by treating contaminated surfaces with DEE chemicals and exposing them to RF radiation. This hybrid approach offers two distinct advantages over other technologies: (1) it allows the use of very low concentrations of decontaminants, significantly reducing costs and mitigating material compatibility and environmental contamination issues; and (2) the transient active biocide species (oxygen containing radicals) can be continuously regenerated to prevent interactions with materials and the need for reapplication. However, bleach is harmful to surfaces. Furthermore, because carbon black is conductive, it tends to penetrate surface-mounted equipment (e.g., computers) and cause electrical shorts.

[0011] U.S. Patent Application Publication No. 20180007922, "Microwave Decontamination Method and System for Food Surfaces," describes a method and system for decontaminating food surfaces, such as meat pieces. The method involves treating food and / or meat pieces with microwaves in the 0.5-18 GHz range, e.g., 4-18 GHz. This method has been used to treat meat pieces whose surfaces are contaminated with Clostridium botulinum spores or Clostridium botulinum vegetative cells. U.S. Patent Application Publication No. 6,797,242, "Chemical and Biological Decontamination System," discloses a system that generates singlet delta oxygen to neutralize chemical and biological contaminants. This system is capable of decontaminating large volumes of contaminated air and is not limited by the humidity of the air. U.S. Patent Application Publication No. 7,629,918, "Multifunctional Radio-Frequency Directed Energy System," discloses a system comprising a radio-frequency transmitter and antenna that directs high-power electromagnetic energy to a target sufficient to cause high-energy damage or destruction of the target. U.S. Patent No. 8,943,744, "Apparatus and Method for Using Microwave Energy for Insect and Pest Control," discloses an apparatus for using microwave energy to treat sites infested with insects or other small pests. The apparatus includes a microwave energy source, a transmission element, and an antenna connected to a power source and a power controller. A method for using such an apparatus for treating infected sites is also disclosed. Lai et al. (2005) disclose a portable microwave plasma torch operated with an airflow for decontamination of biological warfare agents. Emission spectroscopy of the plasma torch demonstrated that it produced abundant reactive atomic oxygen capable of effectively oxidizing biological agents. Bacillus cereus was selected as a simulant for the biological agent Bacillus anthracis spores in decontamination experiments. Experimental results showed that all spores were killed in less than 8 seconds at a distance of 3 cm from the torch nozzle, 12 seconds at a distance of 4 cm, and 16 seconds at a distance of 5 cm.

[0012] Since then, the threat posed by aerosolized biological agents has remained a major concern for the U.S. government due to the potentially disastrous consequences for life and property. Two major threat scenarios of particular concern are: (1) pathogen release within enclosed structures (e.g., office buildings, airports, mass transit facilities), where HVAC systems can effectively disperse pathogens throughout the structure, and (2) widespread release of agents throughout populated areas such as towns and cities. Exposure to released aerosolized agents can result in mass casualties. Widespread releases make it extremely difficult to protect citizens from initial exposure. Safe, effective, and environmentally friendly solutions are needed to mitigate the long-term effects associated with re-aerosolization and exposure to surface-deposited agents and minimize surface damage. Methods and systems that do not use hazardous chemicals are needed to quickly and cost-effectively decontaminate surfaces, both in enclosed structures and over large areas, without causing material damage or adverse effects to humans. DEE chemical formulations with low chemical toxicity, minimal corrosion, and high environmental tolerance are needed. It is desirable to achieve at least a six-log reduction in biological contaminants using treatment methods at low temperatures, preferably near ambient temperatures. Summary of the Invention

[0013] Exemplary methods and systems are disclosed for decontaminating various surfaces in both enclosed structures and large areas. Specifically, the systems and methods involve treating the surfaces with a non-hazardous chemical formulation followed by briefly exposing the surfaces to radio frequency radiation (microwaves).

[0014] A mobile decontamination system for treating contaminated surfaces located outside of a system is disclosed, the mobile decontamination system including: one or more onboard tanks for storing a directed energy enhancer (DEE) formulation in each of the onboard tanks; a sprayer subsystem removably connected to a fluid manifold and having a plurality of nozzles in fluid communication with the one or more storage tanks for spraying the DEE formulation at a predetermined spray rate and substantially coating the contaminated surface to form a coated surface; a radio frequency (RF) subsystem having a microwave generator configured to generate microwave radiation at a predetermined frequency and a plurality of pyramidal horn antennas for directing the microwave radiation toward the coated surface; a locomotion subsystem having an undercarriage with motorized wheels, at least one of computer vision, GPS, ultrasonic proximity sensor, optical sensor, sonar sensor, and gyroscope; and a robotic platform control system; a power source; and a control system arranged in bidirectional communication with the spray subsystem, the RF subsystem, the locomotion subsystem, and the power source. The nozzle may include at least one of a flat fan nozzle, an extended range flat fan nozzle, an even flat fan nozzle, a twin orifice flat fan nozzle, a flood nozzle, a hollow cone orifice nozzle, and a full cone orifice nozzle. The microwave RF radiation may be characterized by a frequency between about 2.35 GHz and about 2.65 GHz. The microwave irradiation may be characterized by a frequency of about 2.45 GHz. The system may be configured to be remotely controlled by a human operator. The system may be configured to operate substantially autonomously. The microwave generator may have a power output of about 1 W / cm. 2 to about 2 W / cm 2The DEE formulation may have approximately 2.5% PCSR by weight in water. The control system may be configured to control movement of the robotic mobility platform using input from at least one of computer vision, GPS, ultrasonic proximity sensors, optical sensors, sonar sensors, and gyroscopes. The control system may be configured to control at least one of power supply to the microwave generator, transfer of a predetermined amount of DEE formulation from the tank to the plurality of nozzles, focusing of the plurality of nozzles to ensure coating of the contaminated surface, transmission of microwave radiation from a microwave generator through a plurality of horn antennas, and focusing of the microwave radiation onto the coated surface. The control system may be configured to measure the amount of DEE remaining in the one or more tanks using an initial amount of DEE formulation in the one or more tanks, a spray rate from the one or more nozzles, and a spray time corresponding to the one or more spray rates. The control system may further include a data acquisition component and a data transfer component for transferring data to a remote server. The data can include at least one of the following: a composition of the DEE formulation, an amount of the DEE formulation used to treat the contaminated surface, an amount of the DEE formulation remaining in one or more tanks, a frequency of the microwave radiation used, a power density of the microwave radiation, a microwave radiation treatment time, and a type of contaminant. The system power source can be in electrical communication with at least one of a battery pack installed on the system, a power source available onboard the aircraft, and a power source available to ground support when the aircraft is parked at an airport. The system can be powered by a suitable battery pack located onboard the system.

[0015] A method for treating a contaminated surface located outside the system is disclosed, the method comprising: providing the mobile decontamination system; spraying a DEE formulation onto the contaminated surface to substantially coat the contaminated surface to form a coated surface, the DEE formulation having about 2.5% by weight of PCSR in water; and exposing the coated surface to microwave radiation for a predetermined exposure time to substantially decontaminate the coated surface and produce a treated surface, the treated surface being characterized by at least a 6-log reduction in contaminants. The DEE formulation may further comprise about 1% by weight of a surfactant. The contaminated surface may include at least one of metal, concrete, plastic, and wood. The contaminated surface may include at least one of a surface in a hospital room, an aircraft, or an office building. The surface contaminant may comprise at least one of 229E (alphacoronavirus), NL63 (alphacoronavirus), OC43 (betacoronavirus), HKU1 (betacoronavirus), MERS-CoV, SARS-CoV, and SARS-coronavirus-2. The microwave irradiation may be characterized by a frequency between about 2.35 GHz and about 2.65 GHz. The microwave irradiation may be characterized by a frequency of about 2.45 GHz. The microwave irradiation may be characterized by a thermal power output of about 500 W to about 2000 W. The predetermined exposure time for microwave irradiation exposure may be between about 10 seconds and about 45 seconds. The predetermined exposure time for microwave irradiation exposure may be between about 15 seconds and about 30 seconds.

[0016] A microwave-assisted surface decontamination method for treating surfaces contaminated with contaminants is disclosed, teetha method for producing a treated surface characterized by at least a 6-log reduction in contaminants, comprising spraying a DEE formulation onto the contaminated surface to substantially coat the contaminated surface to form a coated surface, the DEE formulation having about 2.5% by weight PCSR in water, waiting a predetermined hold time, and exposing the coated surface to microwave radiation for a predetermined exposure time to substantially decontaminate the coated surface and produce a treated surface, the treated surface being characterized by at least a 6-log reduction in contaminants, the predetermined hold time can be between about 15 seconds and about 45 seconds.

[0017] A DEE formulation for use in microwave-assisted surface decontamination is disclosed, which may have about 2.5 wt. % PCSR in water, and may further have about 1 wt. % surfactant in water.

[0018] Other features and advantages of the present disclosure will become apparent to those skilled in the art upon examination of the following detailed description, which is set forth in part in the following description and the accompanying drawings, in which preferred aspects of the disclosure are described and illustrated, and which, in part, are taken in conjunction with the accompanying drawings, or may be learned by the practice of the present disclosure. The advantages of the present disclosure may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims. [Brief explanation of the drawings]

[0019] The foregoing aspects and many of the attendant advantages of the present disclosure will be more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings. [Figure 1] FIG. 1 is a schematic diagram of an exemplary microwave-assisted method for surface decontamination. [Figure 2] FIG. 2 is a perspective view of an exemplary microwave-assisted apparatus for surface decontamination. [Figure 3]FIG. 3 is a perspective view of another exemplary microwave-assisted apparatus for surface decontamination. [Figure 4] FIG. 4 is a perspective (exploded) view of an exemplary microwave-assisted decontamination apparatus with a graphical user interface. [Figure 5] FIG. 5 is a perspective view of an exemplary microwave-assisted decontamination apparatus with a graphical user interface.

[0020] All reference numbers, identifiers, and callouts in the figures are incorporated herein by this reference as if fully set forth herein. Failure to number elements in the figures is not intended as a waiver of any rights. Non-numbered references may also be identified by the alphabetic letter of the figure or appendix.

[0021] The following detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments in which the disclosed systems and methods may be practiced. These embodiments, which may be understood as "examples" or "options," are described in sufficient detail to enable one skilled in the art to practice the invention. The embodiments may be combined, other embodiments may be utilized, or structural or logical changes may be made without departing from the scope of the invention. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of the invention is defined by the appended claims and their legal equivalents.

[0022] In this disclosure, the singular (equivalent to the English terms "a" or "an") is used to include one or more, and the term "or" is used to refer to a non-exclusive "or" unless otherwise specified. Furthermore, expressions or terms used herein and not otherwise defined should be understood to be for descriptive purposes only and not for limiting purposes. Unless otherwise specified in this disclosure, for purposes of interpreting the scope of the term "about," the margin of error associated with disclosed values (dimensions, operating conditions, etc.) is ±10% of the value set forth in this disclosure. The margin of error associated with values disclosed as percentages is ±1% of the stated percentage. The word "substantially" used before certain words includes the meanings "a significant portion of the specified range" and "most but not all of what is specified." Detailed Description

[0023] Particular aspects of the present invention are described below in considerable detail for the purposes of explaining the organization, principles, and operation of the disclosed methods and systems. However, various modifications may be made and the scope of the invention is not limited to the exemplary aspects described.

[0024] Treating contaminated surfaces with the exemplary DEE formulations disclosed herein, followed by exposure to RF irradiation, can be used to destroy viruses, such as MS2 bacteriophage, which is commonly used as a surrogate for pathogenic human viruses, such as SARS-Coronavirus-2. These exemplary treatment methods can be used to destroy viruses, such as MS2 bacteriophage, which is used as a surrogate for pathogenic human viruses, such as SARS-Coronavirus-2. The viruses can include at least one of 229E (alphacoronavirus), NL63 (alphacoronavirus), OC43 (betacoronavirus), HKU1 (betacoronavirus), MERS-CoV, SARS-CoV, and SARS-Coronavirus-2. MS2 bacteriophage viruses are significantly more difficult to inactivate or destroy than enveloped viruses, such as SARS-Coronavirus-2. Without being bound by theory, MS2 bacteriophage may infect bacterial hosts, such as E. coli. Once inside the host cell, they can hijack the host cell and use the cell's resources to propagate into new phages. Once MS2 phage assembly is complete, the host cell lyses. The DEE formulations disclosed herein are effective at destroying viruses on various surfaces when the treated surfaces are exposed to RF radiation. An exemplary DEE formulation for killing viruses can have about 2.5% by weight of percarbonate-based stain remover (PSCR) in water. An exemplary PCSR is commercially available as OxiClean (Church & Dwight Co., Inc.). The PCSR preferably has about 66% by weight sodium percarbonate (e.g., 2Na2CO3:3H2O2, sodium carbonate perhydrogen hydrate) and about 34% by weight sodium carbonate. The surface treated with the exemplary DEE formulation can then be exposed to about 2.45 GHz RF radiation for about 10 seconds to about 45 seconds. Alternatively, the surface treated with the exemplary DEE formulation may be exposed to RF radiation at about 2.45 GHz for about 15 seconds to about 30 seconds. Further details are provided in Example 1 of this disclosure.The DEE formulation may also include copper and iron salts in water. Furthermore, an exemplary DEE formulation for decontaminating virus-contaminated surfaces may be unbleached. An exemplary DEE formulation for virus decontamination may be surfactant-free. For decontaminating porous surfaces, such as virus-contaminated wood, an exemplary DEE formulation may include a surfactant to ensure penetration of the DEE formulation into the pores. An exemplary surfactant may include the commercially available Tween 80 (Sigma-Aldrich) surfactant, which is a polyethylene sorbitol ester also known as polysorbate 80, PEG(80) sorbitan monooleate, and polyoxyethylene sorbitan monooleate. Tween 80 is used in detergents, soaps, cosmetics, mouthwash, and ice cream and is a substantially harmless chemical. The surfactant may have a calculated molecular weight of 1310 Daltons. Typically, the fatty acid composition is approximately 70% oleic acid by weight, with the remainder being primarily linoleic, palmitic, and stearic acids. The oleic acid concentration is typically ≧58.0% by weight. Exemplary DEE formulations and treatment methods can be used to decontaminate surfaces contaminated with pathogenic human viruses, such as SARS-coronavirus-2.

[0025] An exemplary mobile decontamination system 200 (FIGS. 2-5) is disclosed, which may be in the form of a mobile cart 201. The system may include a container (not shown) holding a predetermined amount of DEE formulation and fluidic components (e.g., pumps, valves, etc.) for transferring the DEE formulation from the container to a manifold 204, which is in fluid communication with one or more spray nozzles 202. An exemplary DEE formulation includes approximately 2.5% by weight percarbonate-based stain remover (PSCR) in water. An exemplary PCSR is commercially available as OxiClean (Church & Dwight Co., Inc.). Another exemplary DEE formulation includes approximately 2.5% by weight PCR and approximately 1% by weight surfactant in water. The surfactant distributes the chemicals across the surface. An exemplary surfactant may include commercially available Tween 80 (Sigma Aldrich) surfactant. The nozzle 202 may be oriented to ensure rapid and complete (or substantially complete) exposure of the contaminated surface to the spray of the DEE formulation. Microwave radiation (e.g., a frequency of about 2.35 GHz to about 2.65 GHz, preferably about 2.45 GHz) from a microwave generator (not shown) can be directed toward the spray surface using a pyramidal horn antenna 203. The antenna orientation can also be adjusted / changed to quickly irradiate the contaminated surface after DEE spray treatment. The DEE formulation container and microwave generator can be housed within a cart 201 and accessed using a door 205. The cart can incorporate a fan system 206 ( FIG. 3 ) with one or more fans 207 to disperse the DEE formulation exiting one or more nozzles 202. The spray nozzles 202 can comprise small-scale agricultural sprayers or nozzles. The flow or spray patterns from these nozzles are well characterized, and various types of nozzles can be selected to produce the precise spray pattern needed to quickly cover or treat the contaminated surface or area with the DEE formulation.Nozzle types may include, but are not limited to, a flat fan nozzle, an extended range flat fan nozzle, a flat fan nozzle, a twin orifice-flat fan nozzle, a flood nozzle, a hollow cone orifice nozzle, and a full cone orifice nozzle. An exemplary system 200 may include a sprayer subsystem having a nozzle 202, a pump 208, a fan system 206, a manifold 204, and a DEE formulation container 209 ( FIG. 4 ). Multiple containers 209 may be used in the exemplary system. The pump 208 may include at least one of a centrifugal pump, a diaphragm pump, a piston pump, a roller pump, and an irrigation pump.

[0026] One or more fans 207 may be removably attached to the cart to decontaminate small spaces within enclosed structures. Alternatively, the fan system 206 may be tethered to the cart for decontamination of larger spaces or large areas. The tether is configured to provide two-way communication with a control system (system master controller). The airflow rate output from the one or more fans 207 may be adjusted depending on the size of the space to be decontaminated. Preferably, the airflow rate of the one or more fans 207 is between about 150 cubic feet per minute and about 250 cubic feet per minute and may be varied to optimize the dispersion and deposition of the DEE formulation on the contaminated surface. In addition to the one or more fans, the fan system 206 may include power components for operating the fans and control components for communicating with the system master controller. Components such as the power supply, magnetron, controller, and microwave transmission elements, as well as controllers for transporting and spraying the DEE formulation, are preferably housed within the cart 201. The master controller may control the cart movement, spraying, operation of the fan system, and microwave processing steps. Commercially available magnetrons may be used, such as resonant cavity magnetrons designed for domestic microwave ovens rated at 500 W to 2 kW. The exemplary system 200 may be used to substantially decontaminate surfaces in an enclosed area (e.g., a room). The system may be scaled up to cover a wide area (1 km 2 For a typical DEE formulation containing about 1% by weight surfactant and about 1% by weight PCSR in water, about 2500 kg of DEE (2000 kg of solid PCSR such as OxiClean and 500 kg of Tween 80 surfactant) can be treated with a 1 km 2This may be sufficient to decontaminate an area of 1000 m2, representing a 10-fold reduction in chemicals required when using conventional chemicals such as Spor-Klenz without microwave irradiation. Spor-Klenz may have an approximately 6% hydrogen peroxide solution, and approximately 0.525% hypochlorite solution (Steris Life Sciences) is used. For an exemplary DEE formulation containing 0.06 M copper(II) chloride in water, 2500 kg of copper(II) chloride is needed to decontaminate an area of 1 km2. 2 This will be sufficient to substantially decontaminate the surface of the area. The exemplary DEE formulations disclosed herein are benign to both surfaces and humans. The DEE formulation sprayer may be in the form of a sprayer. The antenna 203 may be operated using an RF control system 210, a power converter 211, and one or more power sources 212. The exemplary cart 200 uses a control system 210, which may have an RF subsystem with the antenna 203 and one or more power sources (microwave generators) 212, to control the frequency of the RF radiation, the frequency band of the RF radiation, the power density (W / cm 2 or mW / cm 2 ), and RF irradiation exposure time.

[0027] The cart 201 can be configured to be remotely operated by a human operator. The cart can be substantially autonomous, meaning it can sense its environment and move with minimal human input. It can use multiple sensors to sense its surroundings and for navigation, including, but not limited to, radar, computer vision, GPS, ultrasonic proximity sensors, optical sensors, sonar, and gyroscopes. The robotic locomotion subsystem can include an undercarriage including sensors, motors, and wheels within the cart 201. The cart 201 and the sprayer subsystem, RF subsystem, and locomotion subsystem can be controlled using a graphical user interface 213 and a control system 210 that communicate bidirectionally with each other. The system 200 can be built on a robotic platform, such as a six-wheel drive (6WD) all-terrain robotic platform (SuperDroid Robots, Fuquay-Varina, NC). The motors and drivetrain of the robotic platform can be controlled using a robotic platform control system, which can be configured to receive commands from and communicate with the control system 210. The sprayer subsystem and control system 210 can be configured to measure the amount of DEE remaining in the container 209 using at least one of the initial amount of DEE formulation, one or more spray rates from the nozzle 202, and spray times corresponding to the one or more spray rates. During surface treatment, the spray rate can be constant or can be varied using a predetermined spraying protocol. Upon reaching a predetermined consumption amount, the control system 210 can issue an alert via the user interface 213 and replace or refill the container 209. The power converter 211 can be used to power the robotic movement subsystem, for example, using 100V, 400Hz power available on military and civilian aircraft, or 28VDC on military aircraft. The DEE container 209, control system 210, microwave generator 213, and power converter 211 can be housed within the cart 201 (FIGS. 4-5).In another exemplary cart 201 with multiple DEE formulation containers 209, one or more different DEE formulations can be provided in one or more containers.

[0028] Microwave generators that produce microwave radiation at approximately 2.45 GHz are commercially available. For example, such generators are used in household microwave ovens. For aircraft decontamination, an important consideration in selecting the microwave frequency and power density is to ensure that the aircraft's electronics are not damaged during the decontamination process. For example, military aircraft electronics must be tested to meet MIL-STD-461G standards. Radars, communication systems, and jammers are all part of the airspace under combat operations. The ASR-9 aircraft surveillance radar used by the Federal Aviation Administration operates between approximately 2.7 GHz and approximately 2.9 GHz. The RF power density required using a commercially available microwave generator that outputs microwave RF radiation at approximately 2.45 GHz is approximately 1 W / cm. 2 and approximately 2 W / cm 2 The RF power density can be characterized by an upper limit between 1 / R 2 Since the power density decreases as a function of , where R is the distance from the RF generator, we can set the power density at a distance of 10 cm from the contaminated surface inside the aircraft to 1 W / cm 2 Assuming this, the power density is 0.1 mW / cm at a distance of 10 m. 2 and is significantly lower than the transmit power density near a mobile phone.

[0029] FIG. 1 shows a schematic diagram of an exemplary method 100 for microwave-assisted surface decontamination using an exemplary DEE formulation disclosed herein. The type of surface and the nature of the decontaminating agent can be determined in step 101. An approximate concentration of the contaminant can also be determined in step 101. An exemplary surface can include at least one of metal, concrete, plastic, and wood. An exemplary contaminant (spores and / or vegetative cells) can include at least one of B. anthracis, B. thuringiensis, and P. roqueforti. Based on the information collected in step 101, an exemplary DEE formulation disclosed herein can be selected for surface coating in step 102. In addition to the previously disclosed DEE formulations, another DEE formulation effective for decontaminating various types of surfaces can include PCSR, copper(II) chloride, and bleach in water. The DEE formulation may have about 1% to about 10% by weight of PCSR, about 0.05M to about 0.1M copper(II) chloride, and at least about 100 ppm of bleaching agent, with the remainder being water. Other DEE formulations may have about 1% to about 10% by weight of PCSR, about 0.06M copper(II) chloride, and at least about 250 ppm of bleaching agent, with the remainder being water. The bleaching agent content is preferably about 250 ppm to about 1000 ppm. The selected DEE formulation may then be applied to the contaminated surface by spraying or other suitable means in step 103. Subsequently, in step 104, the contaminated surface coated with the DEE formulation may be exposed to radio frequency (microwave) radiation. The method may include a hold time, defined as the period between coating the surface with the DEE formulation and exposing the coated surface to RF radiation in step 104. The irradiation frequency is preferably 2.45 GHz, which can be generated using a commercially available microwave generator. The coated surface can be exposed to irradiation for at least 10 seconds. The exposure time can be between about 10 seconds and about 120 seconds. Alternatively, the exposure time can be between about 30 seconds and about 60 seconds.At least one of the treated surface sample and one or more calibrated test sample strips can be analyzed in step 105 to determine the concentration of contaminants. One or more test sample strips can be placed adjacent to the surface to be decontaminated. Examples of test sample strips include, but are not limited to, biological indicator spore strips provided by Mesa Labs (Bozeman, Montana). If at least a 6-log reduction in contaminants is achieved, the surface can be considered decontaminated and method 100 can be stopped. If step 105 indicates that additional processing is required, at least one of steps 103 and 104 can be repeated in step 106. In step 106, the DEE formulation can be modified (e.g., a different DEE formulation can be used) to enhance the destruction of surface contaminants. The duration of microwave radiation exposure can also be extended to achieve at least a 6-log reduction in biological contaminants.

[0030] Exemplary directed energy enhancers ("DEEs"), when exposed to radiofrequency radiation, generate reactive oxidizing species (oxygen radicals, including but not limited to singlet oxygen, OH, and OOH radicals). These oxidizing species then destroy biological agents, including, but not limited to, Bacillus anthracis (anthrax) and molds (e.g., Penicillium roqueforti) in the form of spores or vegetative species. Spores generally resist heat, desiccation, chemicals, and radiation. Bacteria can form endospores approximately 6-8 hours after exposure to adverse conditions. Normal growing cells that form endospores are called vegetative cells. Spores are metabolically inactive and dehydrated.

[0031] An exemplary DEE chemical composition may include copper(II) chloride, ascorbic acid, and at least one of a salt in water. The salt concentration may be between about 0.5M and about 1.5M, preferably about 1M. 1M generally means one mole of solute per liter of solution. The salt may include sodium chloride. Copper(II) chloride dihydrate may be used to generate copper(II) ions in solution. The copper(II) chloride concentration may be between about 0.05M and about 1M, preferably between about 0.06M and 0.6M. The ascorbic acid concentration may be about 1M. These chemicals are commonly available food additives, household chemicals, and approved insecticides and fungicides. For example, copper salts may be common biocides / fungicides suitable for use in certified organic foods. Ascorbic acid is a chemical component of vitamin C. Without being bound by any theory, these exemplary compositions are highly effective DEE chemical formulations because they generate reactive oxidizing species when exposed to radio frequency (microwave) radiation.

[0032] In addition to copper(II) salts, other salts may be used to generate metal ions in solution. Exemplary metal salts include, but are not limited to, cathelite (tin oxide), manganite (manganese oxide), transition metal oxides including iron, chromium, and cobalt oxides, nickel oxide, zinc oxide, lanthanide oxides, semiconductors such as p-doped and n-doped silicon, gallium arsenide, indium tin oxide, silicon carbide, and refractory metal nitrides and oxides, or mixtures thereof.

[0033] Another exemplary DEE chemical composition may have about 0.6 M copper(II) chloride and about 0.1 M ascorbic acid in water. Another exemplary DEE chemical composition may have about 0.6 M copper(II) chloride, about 0.1 M ascorbic acid, and about 1 wt. % surfactant, with the remainder being water. Another exemplary DEE chemical composition may have about 0.6 M copper(II) chloride, about 0.1 M ascorbic acid, about 1 wt. % surfactant, and about 1 M salt in water.

[0034] Another exemplary DEE chemical composition may include at least one of a surfactant and a percarbonate-based stain remover ("PCSR"). An exemplary PCSR is commercially available as OxiClean (Church & Dwight Co., Inc.). The PCSR preferably includes about 66% by weight sodium percarbonate (e.g., 2Na2CO3:3H2O2) and about 34% by weight sodium carbonate. The surfactant concentration in the exemplary DEE formulation may be about 1% to 10% by weight, preferably about 1% by weight. The PCSR concentration in the exemplary DEE formulation may be between about 1% and about 10% by weight.

[0035] Another exemplary DEE formulation may include at least one of copper(II) chloride, a surfactant, PCSR, and sodium chloride in water. The sodium chloride concentration in the DEE formulation may be between about 0.5M and about 1.5M, preferably about 1M. The copper(II) chloride concentration may be between about 0.05M and about 1M. The surfactant concentration may be between about 0.5% and about 1% by weight. The surfactant concentration may be about 1% by weight. The PCSR concentration may be between about 1% and about 10% by weight. Another exemplary DEE composition may include about 0.06M copper(II) chloride, about 1% by weight surfactant, between about 1% and about 10% by weight PCSR, and about 1M salt in water. The salt may include sodium chloride.

[0036] Another exemplary DEE composition may include at least one of a surfactant and a bleaching agent in water. An exemplary bleaching agent is concentrated Clorox Regular Bleach, which has about 6% by weight sodium hypochlorite (NaOCl). The surfactant concentration may be between about 0.5% and about 1% by weight. The bleaching agent concentration may be between about 1% and 10% by weight.

[0037] Another exemplary composition may include at least one of copper(II) chloride, a surfactant, a bleaching agent, and sodium chloride in water. The surfactant concentration may be between about 0.5% and about 1% by weight. The bleaching agent composition may be between about 1% and 10% by weight. The sodium chloride composition may be between about 0.5M and about 1M. The copper(II) chloride concentration may be between about 0.05M and 1M. Another exemplary composition may include about 0.06M copper(II) chloride, about 1M sodium chloride, about 1% by weight surfactant, and about 1% to about 10% by weight bleach in water.

[0038] Another exemplary composition may include at least one of copper(II) chloride, ascorbic acid, and a surfactant in water. The surfactant concentration may be between about 0.5% and about 1% by weight. The ascorbic acid concentration may be between about 0.01M and about 1M. The copper(II) chloride concentration may be between about 0.05M and 1M. Another exemplary DEE composition may include about 0.06M copper(II) chloride in water. Another exemplary DEE composition may include about 0.06M copper(II) chloride, about 1M sodium chloride, and about 0.1M ascorbic acid.

[0039] Another exemplary composition may include copper(II) chloride, hydrogen peroxide, and at least one of a surfactant in water. The surfactant concentration may be between about 0.5% and about 1% by weight. The hydrogen peroxide concentration may be between about 0.01M and about 1M. The copper(II) chloride concentration may be between about 0.05M and 1M. Another exemplary composition may include about 0.06M copper(II) chloride, about 1M sodium chloride, about 1% by weight surfactant, and about 0.1M hydrogen peroxide.

[0040] Another exemplary DEE composition may include at least one of a surfactant and PCSR in water. The surfactant concentration may be between about 0.5% and about 1% by weight. The PCSR concentration may be between about 1% and about 10% by weight. Another exemplary composition may include about 1% by weight surfactant and about 10% by weight PCSR in water. Another exemplary composition may include about 1% by weight surfactant and about 1% by weight PCSR in water.

[0041] The microwave radiation may have a frequency less than about 300 MHz and at least about 300 GHz, such as from about 300 MHz to about 300 GHz, from about 1 GHz to about 125 GHz, or from about 2.4 GHz to about 95 GHz. The frequency may be substantially a single frequency, such as about 2.4 GHz, about 10 GHz, about 50 GHz, or about 95 GHz. Alternatively, the frequency may vary over a range during the exposure period, such as from about 1 GHz to about 125 GHz or from about 2.4 GHz to about 95 GHz. In some embodiments, about 2.45 GHz is used to treat extended surfaces, such as the surface of a ground or building. In other embodiments, about 95 GHz is used to treat delicate and / or complex surfaces.

[0042] Raytheon Company is developing a series of full-scale, field-deployable 95 GHz systems to support the Active Denial System (a U.S. Department of Defense non-lethal weapons program). These systems can be used to decontaminate surfaces using the exemplary methods disclosed herein. The 95 GHz systems feature output powers of 100 W (watts), 400 W, and 100,000 W. The 100 W system is a continuous wave system with a fixed focus and fixed power output. Power density can be adjusted by varying the antenna distance from the target. The 400 W system is a variable focus and variable power, pulsed output system that can vary average power by changing the duty cycle. The 100 kW system is a large vehicle-mounted system with a significant range (over 500 m) and the ability to vary its output power.

[0043] Without being bound by any particular theory, irradiation of the exemplary DEE formulation sprayed onto the contaminated surface may generate at least one of highly reactive singlet oxygen and hydroxyl radicals (including, but not limited to, OH, OOH radicals), presumably through the decomposition of hydrogen peroxide released from the PCSR in solution. This destroys biological contaminants. Copper(II) chloride is used to convert copper to Cu during the decomposition of peroxide. 2+ The decomposition of hydrogen peroxide using transition metal elements is commonly known as Fenton chemistry. Cu 2+ Cu was generated during the decomposition of peroxide by microwave irradiation. 3+ is oxidized to Cu and reduced to Cu 2+ Instead, follow the Cu-Fenton process to 2+ Cu + and Cu 2+ Microwave irradiation is thought to accelerate the underlying redox chemistry.

[0044] The exemplary decontamination systems and methods can be used to mitigate insect infestations in hospitality markets in an environmentally friendly manner. Of particular interest is the remediation of bed bug (Cimex lectularius) infestations. Additionally, the exemplary decontamination systems and methods can be used for hospital room decontamination, defense sector equipment decontamination, commercial aircraft decontamination, and first responder / hazardous materials equipment decontamination, including when the contaminant is a virus such as the COVID-19 coronavirus.

[0045] Contaminated surfaces, including but not limited to concrete, wood, soil, galvanized metal, glass, plastic, and painted wallboard, can be treated using the methods disclosed herein to achieve at least a 6-log reduction in biological contaminants, such as the anthrax simulant B. thuringiensis. The decontamination method is effective over a wide range of ambient temperatures and humidities, particularly low / low humidity (about 0°C to about 25°C and about 5% to about 40% relative humidity), normal temperature / medium humidity (about 20°C to about 30°C and 40% to 50% relative humidity), and high temperature / high humidity conditions (about 30°C to about 50°C and about 50% to about 95% relative humidity).

[0046] Example 1: Disruption of MS2 Bacteriophage Virus Using Representative DEE Formulations and Exposure to RF (Microwave) Radiation at Approximately 2.45 GHz Plaque assays for enumeration of active MS2 bacteriophage virus (ZeptoMetric Corp., catalog number 0810066) were performed using the E. coli host cell line C3000 (ATCC 15597). Briefly, MS2 bacteriophage was pipetted onto glass disk coupons containing E. coli grown on agar media to mimic common surfaces in buildings, public places, etc., and allowed to dry. The glass disks were treated with an exemplary DEE formulation containing approximately 2.5% by weight of a percarbonate-based stain remover (PSCR) in water. An exemplary PCSR is commercially available OxiClean (Church & Dwight Co., Inc.). The PCSR preferably contains approximately 66% by weight sodium percarbonate (e.g., 2Na2CO3:3H2O2, sodium carbonate perhydrogen hydrate) and approximately 34% by weight sodium carbonate. The glass disks were then exposed to approximately 2.45 GHz RF microwave radiation for approximately 15 to 30 seconds. A >6-log reduction in MS2 was observed with this treatment, indicating that the MS2 virus was inactivated with high levels of effectiveness at both the 15- and 30-second treatment times. A control study was conducted using glass disks containing MS2 treated with water. No reduction in MS2 virus count was observed when exposed to approximately 2.45 GHz RF radiation. Similarly, treatment of glass disks with MS2 containing an exemplary DEE formulation having approximately 2.5% by weight PSCR did not result in a significant reduction in virus count when the disks were not exposed to approximately 2.45 GHz RF radiation.

[0047] The Abstract is provided to comply with 37 C.FR § 1.72(b) to enable the reader to quickly determine the nature and gist of the technical disclosure from a broad perspective, and should not be used to interpret or limit the scope or meaning of the claims.

[0048] While this disclosure has been described in connection with preferred modes of practicing it, those skilled in the art will recognize that many modifications can be made thereto without departing from the spirit of this disclosure. Accordingly, it is not intended that the scope of this disclosure be limited by the foregoing description.

[0049] It is also understood that various modifications can be made without departing from the essence of this disclosure. Such modifications are implicitly included in the description and remain within the scope of this disclosure. It is understood that this disclosure is intended to result in patents covering many aspects of the disclosure, both individually and as a system as a whole, and in method and apparatus modes.

[0050] Moreover, each of the various elements of this disclosure and claims may also be achieved in a variety of ways, and this disclosure should be understood to encompass each such variation, whether it be any device implementation variation, method or process implementation, or simply a variation of any of these elements.

[0051] In particular, it should be understood that each element term may be expressed by equivalent apparatus or method terms, even if only the function or result is the same. Such equivalent, broader, or more general terms should be considered included in the description of each element or operation. Such terms may be substituted where necessary to make clear the implicitly broader scope to which this disclosure is entitled. It should be understood that all operations may be expressed as a means for taking that operation or as an element that causes that operation. Similarly, each physical element disclosed should be understood to encompass a disclosure of the operation that the physical element facilitates.

[0052] Furthermore, for each term used, unless its usage in this application is inconsistent with such interpretation, the common dictionary definition contained, for example, in at least one standard technical dictionary recognized by artisans and the most recent edition of Random House Webster's Unabridged Dictionary, should be understood to be incorporated herein for each term and all definitions, alternative terms, and synonyms.

[0053] Additionally, the use of the transitional phrase "comprising" is used to maintain the "open-ended" claims herein in accordance with conventional claim interpretation. Thus, unless the context requires otherwise, "comprising" is intended to mean the inclusion of a recited element or step or group of elements or steps, but not the exclusion of other elements or steps or group of elements or steps. Such terms should be interpreted in the broadest manner to afford applicant the broadest scope legally permissible.

[0054] [References] 1. Lai W. et al. "Decontamination of biological warfare agents by a microwave plasma torch," Physics of Plasmas 12, 023501 (2005). 2. N. van Doremalen, et al. Aerosol and surface stability of HCoV-19 (SARS-CoV-2) compared to SARS-CoV-1. N. Engl. J. Med. 2020; 382:1564-1567.

Claims

1. 1. A mobile decontamination system for treating contaminated surfaces located external to the mobile decontamination system, comprising: one or more onboard tanks, each of which stores a Directed Energy Enhancer (DEE) formulation (hereinafter referred to as a "DEE formulation"), wherein the DEE formulation is a benign DEE formulation; a sprayer subsystem removably connected to a fluid manifold and having a plurality of nozzles in fluid communication with the one or more storage tanks for spraying the benign DEE formulation and substantially coating the contaminated surface to form a coated surface; a radio frequency subsystem (RF subsystem) having a microwave generator configured to generate microwave radiation at a predetermined frequency and a plurality of pyramidal horn antennas for directing the microwave radiation toward the coated surface; a locomotion subsystem having an undercarriage with wheels driven by motors, at least one of computer vision, GPS, ultrasonic proximity sensors, optical sensors, sonar sensors, and gyroscopes, and a robotic platform control system; Power supply and a control system arranged in bidirectional communication with the sprayer subsystem, the radio frequency subsystem, the mobile subsystem, and the power source, the control system first substantially coating the contaminated surface with the benign DEE formulation, waiting a predetermined hold time, and then directing the microwave radiation to the coated surface.

2. The system of claim 1 , wherein the microwave radiation is characterized by a frequency between about 2.35 GHz and about 2.65 GHz.

3. 10. The system of claim 1, wherein the system is configured to be remotely controlled by a human operator.

4. 10. The system of claim 1, wherein the benign DEE formulation has about 2.5% by weight of a percarbonate-based stain remover (PCSR) in water.

5. 10. The system of claim 1, wherein the control system is configured to control movement of the robotic mobility platform using input from at least one of computer vision, GPS, ultrasonic proximity sensors, optical sensors, sonar sensors, and gyroscopes.

6. 10. The system of claim 1, wherein the control system is configured to control at least one of powering the microwave generator, transferring a predetermined amount of the benign DEE formulation from the tank to the plurality of nozzles, focusing the plurality of nozzles to ensure coating of the contaminated surface, transmitting microwave radiation from the microwave generator through a plurality of horn antennas, and focusing the microwave radiation onto the coated surface.

7. 7. The system of claim 6, wherein the control system measures the amount of the benign DEE formulation remaining in the one or more tanks using an initial amount of the benign DEE formulation in the one or more tanks, a spray rate from the one or more nozzles, and a spray time corresponding to the spray rate.

8. 10. The system of claim 1, further comprising a data acquisition component and a data transfer component for transferring data to a remote server, wherein the data comprises at least one of a composition of the benign DEE formulation, an amount of the benign DEE formulation used to treat a contaminated surface, an amount of the benign DEE formulation remaining in one or more tanks, a frequency of microwave radiation used, a power density of microwave radiation, a microwave radiation treatment time, and a type of contaminant.

9. 10. The system of claim 1, wherein the power source is capable of electrical communication with at least one of a battery pack onboard the system, a power source available on board the aircraft, and a power source available to ground support when the aircraft is parked at an airport.

10. 10. The system of claim 1, wherein the one or more vehicle-mounted tanks, the sprayer subsystem, the radio frequency subsystem, the mobility subsystem, the power source, and the control system are housed within a mobile cart.

11. 1. The system for treating a contaminated surface located outside the system, comprising: a plurality of nozzles removably connected to the fluid manifold and in fluid communication with a DEE formulation storage container for spraying the DEE formulation onto the contaminated surface to substantially coat the contaminated surface, the nozzles being adjustable in orientation, and the DEE formulation being a benign DEE formulation; a plurality of pyramidal horn antennas for directing microwaves from the microwave generator substantially onto the coated surface.

12. The system of claim 11 , wherein the system is housed in a mobile cart.

13. 1. A microwave-assisted surface decontamination method for treating a contaminated surface containing one or more surface contaminants, comprising: spraying a DEE formulation onto the contaminated surface using a decontamination system to substantially coat the contaminated surface to form a coated surface, the contaminated surface being located outside the system and the DEE formulation being a benign DEE formulation; waiting for a predetermined holding time; and exposing the coated surface to microwave radiation for a predetermined exposure time to substantially decontaminate the coated surface and produce a treated surface.

14. 14. The method of claim 13, wherein the predetermined hold time is between about 15 seconds and about 45 seconds.

15. 14. The method of claim 13, wherein the benign DEE formulation has a PCSR of about 2.5% by weight in water.

16. 16. The method of claim 15, wherein the benign DEE formulation further comprises about 1% by weight of a surfactant in water.

17. 14. The method of claim 13, wherein the treated surface is characterized by at least a 6-log reduction in contaminants.

18. The decontamination system is a mobile cart, one or more on-board storage tanks for storing said benign DEE formulation in each tank; an atomizer subsystem in fluid communication with the one or more on-board storage tanks; a radio frequency subsystem including a microwave generator and a plurality of pyramidal horn antennas, the orientation of the pyramidal horn antennas being adjustable; 14. The method of claim 13, further comprising the mobile cart for housing a control system.

19. 14. The method of claim 13, wherein the contaminated surface comprises at least one of a surface in a building, an aircraft, an ambulance, and an outdoor large area.

20. 14. The method of claim 13, wherein the one or more surface contaminants comprise at least one of 229E (alphacoronavirus), NL63 (alphacoronavirus), OC43 (betacoronavirus), HKU1 (betacoronavirus), MERS-CoV, SARS-CoV, and SARS-coronavirus-2.

21. 14. The method of claim 13, wherein the microwave radiation is characterized by a frequency between about 2.35 GHz and about 2.65 GHz.

22. 14. The method of claim 13, wherein the predetermined exposure time is between about 10 seconds and about 45 seconds.

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