BIOCIDAL ACTIVITY AND METHODS OF USE

CROSS-REFERENCES TO RELATED APPLICATIONS

This claims benefit of the filing date of U.S. Provisional Application No. 63/111,509 filed November 9, 2020, the entire content of which is incorporated by reference herein.

FIELD OF THE INVENTION

The present invention generally relates to porous carbon material for use in air filtration systems and devices. Specifically, the invention relates to a hierarchically porous carbon material doped with metal catalysts having biocidal properties for incorporation into filtration systems and devices.

BACKGROUND OF THE INVENTION

Human history has seen its fair share of disease epidemics and pandemics. More recently, outbreaks, such as H1N1, SARS, and COVID-19 have disrupted countless lives and resulted in millions of deaths worldwide. Many of the fastest-spreading and widest-reaching pandemics have been caused by airborne contagions proliferating via community spread. As infected individuals sneeze and cough, droplets and aerosol particles from their lungs carry the contagion. As recent as 2020, the world was in lockdown due to the global COVID-19 pandemic, which is caused by the severe acute respiratory coronavirus 2 (SARS-CoV 2).

As more becomes known about the novel SARS-CoV 2, it is clear that transmission of the virus is due to many mechanisms, including via airborne aerosols. As a result of this most recent pandemic, mask and respirator technology and air filtration systems have come to the forefront. Mask wearing has been commonplace of citizens of nearly every major city around the world and are especially important for healthcare workers on the frontlines caring for the most ill. As a result, there has been much discussion over which masks offer adequate protection, ranging from the N95 mask used in hospitals or the cloth masks worn by some individuals buying groceries or other necessities. In addition, heating ventilation and air conditioning (HVAC) systems in office buildings, schools, homes, and other buildings are being retrofitted with better filtration systems. While all of these air filtering devices and systems have the potential to block or trap aerosols and droplets carrying the virus to at least some extent, they do not actually kill the virus highlighting the need for improvements in filtration technology in combating community spread of airborne disease.

Porous carbon materials have many applications across various fields and industries, including purification and filtration systems. These materials are used to capture or store gases, such as methane, carbon dioxide, or hydrogen; to purify drinking water or air; for metal extraction or purification; in sewage treatment; as a treatment for poisoning, diarrhea, or overdoses; as a catalyst support material; and many others. Furthermore, porous carbon materials can also be found in filters for gas masks, respirators, or in compressed air, and are used in the power industry for the selective capture of carbon dioxide (CO2 sequestration) from power plant flue gas. Typically, the carbon material is processed, or activated, for improved adsorption, functionalities, or to facilitate chemical reactions. The activation process can involve chemical reagents (e.g., using mild or strong acid or base) or activation using gases (e.g., steam activation or ammonia (NH3) activation). However, these carbon materials, while sufficient in capturing or storing gases, do not kill microbial organisms.

On the other hand, certain metal cations, such as Cu ²⁺ , Co ²⁺ , Cd ²⁺ , Ag ⁺ , and Zn ²⁺ are known to exhibit anti-bacterial and/or anti-viral properties. For example, a recent article by Arendsen et al. [“The Use of Copper an Antimicrobial Agent in Health Care, Including Obstetrics and Gynecology” Clinical Microbiology Reviews 32(4):e00125-18 (2019)], notes that copper has been shown to have biocidal effects on a wide range of pathogens, including bacteria, fungi, and viruses. Furthermore, oxides containing bivalent metal ions, such as Mg ²⁺ , Zn ²⁺ , Ni ²⁺ , Pt ²⁺ , and Mn ²⁺ have been shown to interact with and bind to the virus proteins and form metalloproteins thus impacting the viruses survivability and/or pathogenesis. While such material can be used to dope carbon scaffolds to confer biocidal properties to the resulting material, the biocidal activity may not be sufficient to produce cost-effective and efficient filtration material.

Thus, there remains a need in the art for cost-effective and efficient biocidal filtration devices and systems for use in preventing the spread of contagions. SUMMARY OF THE INVENTION

Described herein are hierarchically porous carbon materials with biocidal properties. In particular, hierarchically porous carbon materials are described that are doped with metal catalysts having biocidal activity and, optionally, contain nitrogen in the carbon backbone. The metal catalysts are dispersed across the surface of the carbon phase of the hierarchically porous carbon materials. Moreover, while not intending to be bound by theory, the presence of nitrogen in the carbon backbone may further promote and/or enhance the biocidal activity of the metal catalysts. Furthermore, the hierarchically porous carbon structure provides for more efficient air/fluid flow through and increased surface area. As such, the hierarchically porous carbon materials of the instant disclosure exhibit not only an increased efficiency in sorption as compared to artstandard activated carbon materials, but also increased biocidal activity. Therefore, the hierarchically porous carbon materials provided herein are suitable for use in filtration devices and systems to impart enhanced aerosol and droplet trapping/capturing properties in addition to enhanced microbial-killing efficiency to the filtration devices and systems to significantly reduce disease-causing airborne microorganisms in the circulating environment and prevent community spread of disease.

In one aspect of the invention, provided herein is a biocidal filtration device having a filter member that includes a pyrolyzed hierarchically porous carbon material produced from a self-assembling thermoset polymer composition. The pyrolyzed hierarchically porous carbon material includes a plurality of macropores defined by a wall. These macropores have a diameter of about 0.05 pm to about 100 pm, while the walls of the macropores include a plurality of mesopores defined by a wall, each mesopore having an average diameter of about 2 nm to about 50 nm. Further, the walls of both the macropores and mesopores create a continuous carbon phase. Furthermore, the pyrolyzed hierarchically porous carbon material further comprises a carbon phase surface on which is dispersed about 0.1% to about 30% by wt metal catalyst selected from the group consisting of Cu ²⁺ , Co ²⁺ , Cd ²⁺ , Ag ⁺ , Zn ²⁺ , Mg ²⁺ , Ni ²⁺ , Pt ²⁺ , Mn ²⁺ , copper oxide, zinc oxide, copper oxide/zinc oxide, and a combination thereof. In such an embodiment, the filter member has increased biocidal activity as compared to a filter member in the absence of the pyrolyzed hierarchically porous carbon material. In some embodiments, the self-assembling thermoset polymer composition includes an amine, an aldehyde, and a phenolic compound. In another embodiment, the carbon backbone comprises about 1% to about 10% by wt nitrogen, and the carbon phase surface comprises about 1% to about 20% by wt metal catalyst. In yet another embodiment, the metal catalyst is selected from the group consisting of Cu ²⁺ , Ag ⁺ , Zn ²⁺ , copper oxide, zinc oxide, copper oxide/zinc oxide, and a combination thereof. In some embodiments, the amine is a primary amine, such as, but not limited to 1,6-diaminohexane or lysine. In other embodiments, the aldehyde may be formaldehyde, trioxane, butyraldehyde, or benzaldehyde, and the phenolic compound may be a benzenediol (e.g., 1,3-benzendiol or phenol). Furthermore, the pyrolyzed hierarchically porous carbon material may be made into a powder comprising a plurality of particles having a particle size of less than about 1 mm.

In some embodiments, the filter member further comprises a filter layer comprising fiberglass, metal reinforced fiberglass, cotton, pleated polyester, pleated cotton, nonwoven polypropylene, or nonwoven polyester, and wherein the pyrolyzed hierarchically porous carbon material is disposed on the filter layer. For instance, the filter layer may be made of nonwoven polypropylene or, alternatively, it may be made of fiberglass, metal reinforced fiberglass, pleated polyester, or pleated cotton. In some embodiments, the pyrolyzed hierarchically porous carbon material comprises a plurality of pellets or monoliths.

In another aspect of the invention, the biocidal filtration device described above can be incorporated into a facemask by disposing it between a first and second fabric layer. In yet another aspect, the biocidal filtration device described above can be incorporated into a HVAC or HEPA air filter system or used in the filter cartridge of a respirator.

Another aspect of the invention features a method of reducing an airborne contagion from the environment that includes the steps of providing a biocidal filtration device described above and contacting the biocidal filtration device with a fluid comprising an airborne contagion. In this method the amount of living airborne contagion present in the fluid decreases after contacting the biocidal filtration device for a period of time e.g., 6 hours or 24 hours).

In some embodiments, the fluid comprises air with a plurality of droplets or aerosol on which is disposed the airborne contagion. The contagion may be, for example, a virus, bacteria, or fungi. In one particular embodiment, the airborne contagion is selected from the group consisting of Corynebacterium diphtherias, Bordetella pertussis, Streptococcus pneumoniae, Neisseria meningitidis, Mycobacterium tuberculosis, Staphylococcus sp, Varicella zoster, influenza virus, coronavirus, Measles morbillivirus, Mumps orthorubulavirus, Hantavirus, Pneumocystis pneumonia, and any combination thereof. In another particular embodiment, the airborne contagion is a coronavirus selected from the group consisting of SARS, MERS, COVID-19, and a combination thereof.

Another aspect of the invention features a method of applying hierarchically porous carbon material to a filtration component that includes the steps of (a) providing a sprayable pyrolyzed hierarchically porous carbon composition that includes a solvent solution and a pyrolyzed hierarchically porous carbon powder; (b) providing a filter component; and (c) applying the sprayable pyrolyzed hierarchically porous carbon composition to the filter component at a rate of about 0.5 g to about 2 g per square foot of the filter component. In this aspect, the pyrolyzed hierarchically porous carbon powder is produced from a self-assembling thermoset polymer composition. Moreover, the pyrolyzed hierarchically porous carbon powder comprises a plurality of macropores defined by a wall, wherein the macropores have a diameter of about 0.05 pm to about 100 pm, wherein the walls of the macropores comprise a plurality of mesopores defined by a wall, wherein the mesopores have a diameter of about 2 nm to about 50 nm, and wherein the walls of the macropores and mesopores comprise a continuous carbon phase. The pyrolyzed hierarchically porous carbon material also includes a carbon phase surface on which is dispersed about 0.1% to about 30% by wt metal catalyst selected from the group consisting of Cu ²⁺ , Co ²⁺ , Cd ²⁺ , Ag ⁺ , Zn ²⁺ , Mg ²⁺ , Ni ²⁺ , Pt ²⁺ , Mn ²⁺ , copper oxide, zinc oxide, copper oxide/zinc oxide, and a combination thereof. Further, the pyrolyzed hierarchically porous carbon comprises a plurality of particles having a particle size of less than about 1 mm. In some embodiments, the self-assembling thermoset polymer composition includes an amine, an aldehyde, and a phenolic compound.

In another embodiment, the filter component comprises a filter layer comprising fiberglass, metal reinforced fiberglass, cotton, pleated polyester, pleated cotton, nonwoven polypropylene, or nonwoven polyester, and wherein the pyrolyzed hierarchically porous carbon material is disposed on the filter layer. In other embodiments, the filter layer comprises nonwoven polypropylene or, alternatively, the filter layer comprises fiberglass, metal reinforced fiberglass, pleated polyester, or pleated cotton. In yet others, the filter layer is part of an HVAC system. In some embodiments, the method includes the step of applying the sprayable pyrolyzed hierarchically porous carbon composition to the filter component at a rate of about 1 g per square foot of the filter component. In another embodiment, the carbon backbone comprises about 1% to about 10% by wt nitrogen, and the carbon phase surface comprises about 1% to about 20% by wt metal catalyst. In other embodiments, the metal catalyst is selected from the group consisting of Cu ²⁺ , Ag ⁺ , Zn ²⁺ , copper oxide, zinc oxide, copper oxide/zinc oxide, and a combination thereof. In one embodiment, the solvent solution comprises water, alcohol, or a combination of water and alcohol. For instance, the solvent solution may comprise a 20:80 to 30:70 mixture of water and ethanol.

In yet another aspect of the invention, a sprayable biocidal carbon composition is provided that includes (a) a pyrolyzed hierarchically porous carbon powder that includes a plurality of particles having a particle size of less than about 1 mm and produced from a selfassembling thermoset polymer composition, and (b) a solvent solution. In this aspect, the pyrolyzed hierarchically porous carbon material comprises a plurality of macropores defined by a wall, wherein the macropores have a diameter of about 0.05 pm to about 100 pm, wherein the walls of the macropores comprise a plurality of mesopores defined by a wall, wherein the mesopores have a diameter of about 2 nm to about 50 nm, and wherein the walls of the macropores and mesopores comprise a continuous carbon phase. Further, the pyrolyzed hierarchically porous carbon material includes a carbon phase surface on which is dispersed about 0.1% by wt to about 30% by wt metal catalyst, wherein the metal catalyst is a biocidal metal ion or metal oxide selected from the group consisting of Cu ²⁺ , Co ²⁺ , Cd ²⁺ , Ag ⁺ , Zn ²⁺ , Mg ²⁺ , Ni ²⁺ , Pt ²⁺ , Mn ²⁺ , copper oxide, zinc oxide, copper oxide/zinc oxide, and a combination thereof. The pyrolyzed hierarchically porous carbon powder is suspended in the solvent solution. In another embodiment, the self-assembling thermoset polymer solution includes an organic amine, an aldehyde, and a phenolic compound.

In one embodiment, the concentration of pyrolyzed hierarchically porous carbon powder suspended in the solvent solution is about 0.1 % by wt to about 1% by wt. In another embodiment, the solvent solution comprises an alcohol. In yet another embodiment, the solvent solution comprises ethanol at a concentration of about 60% to about 80% by volume in water. In another embodiment, the carbon backbone comprises about 1% to about 10% by wt nitrogen, and the carbon phase surface comprises about 1% to about 20% by wt metal catalyst (e.g., Cu ²⁺ , Ag ⁺ , Zn ²⁺ , copper oxide, zinc oxide, copper oxide/zinc oxide, or a combination thereof). In another aspect of the invention, a method of incorporating a biocidal carbon composition in a filter component is provided that includes the steps of providing the sprayable biocidal carbon composition described above and spraying the filter component with the sprayable biocidal carbon composition at an application rate of about 0.5 g to about 2 g per ft ² of filter component. In one embodiment, the application rate is about 1 g per ft ² of filter component. In another embodiment, the filter component comprises fiberglass, metal reinforced fiberglass, cotton, pleated polyester, pleated cotton, nonwoven polypropylene, or nonwoven polyester.

Other features and advantages of the invention will be apparent by reference to the drawings, detailed description, and examples that follow.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 depicts a flowchart of an embodiment of the manufacturing method described herein.

Figure 2 depicts a diagram of an embodiment of a continuous method of manufacturing described herein.

Figure 3 is a photograph showing a textile that is untreated (Panel A) as compared to a textile that is sprayed with 10% ZnO/C, batch 1 (Panel B) or 10% ZnO/C, batch 2 (Panel C).

Figure 4 is a group of photographs of petri dishes plated with untreated S. aureus (Panel A) or S. aureus treated with 10% ZnO/C, batch 1 (Panel B), 10% ZnO/C, batch 2 (Panel C), or 10% ZnO/C, batch 3 (Panel D). The diagram depicts the serial dilutions for each treatment group as arranged from Dilution 1 to 3 (top row, left to right), Dilution 4 to 6 (middle row, left to right), and Dilution 7 (bottom plate).

Figure 5 is a group of photographs of petri dishes plated with untreated E. coli F _amp (Panel A) or A. coli F _amp treated with 10% ZnO/C, batch 1 (Panel B), 10% ZnO/C, batch 2 (Panel C), or 10% ZnO/C, batch 3 (Panel D). The diagram depicts the serial dilutions for each treatment group as arranged from Dilution 1 to 3 (top row, left to right), Dilution 4 to 6 (middle row, left to right), and Dilution 7 (bottom plate).

Figure 6 is a group of photographs showing plaques formed on bacteria after Coliphage T4 nebulization through untreated textile (Panel A) as compared to textile treated with 10% ZnO/C (Panel B). The diagram depicts the serial dilutions for each treatment group as arranged from Dilution 5 and 6 (top row, left to right) and Dilution 7 (bottom plate).

Figure 7 is a photograph of petri dishes showing E. coll growth after Coliphage T4 nebulization on a reference sample (Panel A), textile without carbon or metal catalyst (Panel B), textile sprayed with carbon only (Panel C), textile sprayed with 10% ZnO/C (Panel D), and textile sprayed with 10% CuO/C (Panel E).

DETAILED DESCRIPTION OF THE INVENTION

The inventions described herein spring, in part, from the inventors’ discovery that dispersing metal catalysts on the carbon phase surface of hierarchically porous carbon materials confers enhanced the biocidal activity to the carbon scaffold. Moreover, the presence of nitrogen in the carbon backbone potentially enhances the catalytic activity of the metal catalysts and, thus, their biocidal activity. These metal catalysts, which are described in detail below, exhibit biocidal activity on pathogenic microorganisms, such as bacteria, viruses, and fungi. Moreover, the innovative hierarchically porous structure of the carbon material enhances air/liquid flow through the material and has increased surface area for more efficient microbial inactivation. In this manner, the hierarchically porous carbon material of the present disclosure has both superior gas and aerosol sorption and capture characteristics, as well as increased microbe-killing efficacy. Thus, the hierarchically porous carbon material of the present disclosure can be used as monoliths, chips, pellets, or powder for incorporation into filtration systems, such as facemasks, high efficiency particular air filters (HEPA filters), respirators, and heating ventilation and air conditioning (HVAC) systems to improve the air and aerosol filtering capabilities and reduce circulation of airborne contagions and other contaminants. Moreover, the compositions, devices, and systems disclosed herein can be used to reduce community spread of airborne pathogens, such as influenza, H1N1, SARS, MERS, Covid- 19, Streptococcus, and others. As such, the hierarchically porous carbon material of the instant invention provides a novel and innovative solution to address the need in the art for cost-effective filtration systems that can effectively reduce community spread of airborne disease.

For purposes of this document and for clarity, All percentages referred to herein are percentages by weight (wt. %) unless otherwise noted.

Ranges, if used, are used as shorthand to avoid having to list and describe each and every value within the range. Any value within the range can be selected, where appropriate, as the upper value, lower value, or the terminus of the range.

The term “about” refers to the variation in the numerical value of a measurement, e.g. , temperature, weight, percentage, length, concentration, and the like, due to typical error rates of the device used to obtain that measure. In one embodiment, the term “about” means within 5% of the reported numerical value; preferably, the term “about” means within 3% of the reported numerical value.

As used herein, the singular form of a word includes the plural, and vice versa, unless the context clearly dictates otherwise. Thus, the references “a”, “an”, and “the” are generally inclusive of the plurals of the respective terms. Likewise, the terms “include”, “including” and “or” should all be construed to be inclusive, unless such a construction is clearly prohibited from the context. Similarly, the term “examples,” particularly when followed by a listing of terms, is merely exemplary and illustrative and should not be deemed to be exclusive or comprehensive.

The term “comprising” is intended to include embodiments encompassed by the terms “consisting essentially of’ and “consisting of’. Similarly, the term “consisting essentially of’ is intended to include embodiments encompassed by the term “consisting of’.

The term “absorption” as used herein refers to the incorporation of a substance in one state into another substance of a different state, such as a liquid being absorbed by a solid or a gas being absorbed by a liquid.

The term “adsorption” as used herein refers to the physical adherence or the bonding of ions and molecules onto the surface of another phase.

The term “bi-continuous” as used herein refers to a material or structure containing two separate continuous phases such that each phase is continuous, and in which the two phases are interpenetrating, such that it is impossible to separate the two structures without tearing one of the structures.

The term “biocidal” as used herein refers to the capability of a substance to kill, destroy, deter, inactivate, or otherwise render harmless a harmful organism, such as, but not limited to disease-causing bacteria, viruses, and fungi.

The term “continuous” as used herein to refer to a phase means that all points within the phase are directly connected, so that for any two points within a “continuous” phase, there exists a path which connects the two points without leaving the phase.

The term “continuous” as used herein to refer to a manufacturing process or step means that the manufacturing process or step does not necessitate interruption for reasons other than by business decision. Generally, a continuous process can continue so long as requisite inputs (energy, raw materials, personnel, etc.) are available.

The term “highly branched” as used herein means that the polymer is a three dimensionally interconnected bi-continuous network of carbon polymer ligaments

The term “inert” as used herein refers to a substance that is not chemically reactive.

The term “metal catalyst” as used herein refers to any metal, metal ion, or metal oxide with catalytic activity.

The term “monolith” as used herein refers to a macroscopic, single piece of material typically with one or more dimensional pores (i.e., length, width, and/or height) exceeding about 0.1 mm.

The term “particle” as used herein, generally refers to a discrete unit of material, such as a porous carbon material in particulate form, typically with the dimensions (length, width, and/or height) ranging from about 1 pm to about 1 mm. “Particles” may have any shape (e.g., spherical, ovoid, or cubic).

The term “nanoparticle” as used herein generally refers to a particle of any shape having an average particle size from about 1 nm up to, but not including, 1 pm. The size of “nanoparticles” can be experimentally determined using a variety of methods known in the art, including electron microscopy.

The term “phase” as used herein generally refers to a region of material or a structure that has a substantially uniform composition which is a distinct and physically separate portion of a heterogeneous system. The term “phase” does not imply that the material making up a phase is a chemically pure substance, be merely that physical properties of the material making up the phase are essentially uniform throughout the material, and that these properties differ significantly from the physical properties of another phase within the material or structure. Examples of physical properties include density, index of refraction, and chemical composition. A “phase” as used herein may refer to, e.g., a pore or network of pores, a void, or a wall formed from a solid layer of carbon.

The terms “phase homogeneous,” “homogeneous phase,” or “phase homogeneous end state” refer to a mixture of solids, liquids, or gases in which the substances are in a single phase. For instance, a “phase homogeneous” solution is a very stable mixture in which all solids have been dissolved in the solvent and the solute will not separate/precipitate out or be removed by filtration or centrifugation.

The term “pore-forming solid” refers to a solid material that serves as a seed for facilitating nucleation of a self-assembling polymer structure.

The term “polymeric” as used herein refers to a composition or material comprising one or more polymers, co-polymers, and/or block co-polymers.

The term “pyrolysis” refers to the chemical decomposition of organic materials through the application of heat. “Pyrolysis” is a burning process occurring in the absence or near absence of oxygen (or other oxidants) and is distinct from combustion. “Pyrolysis” often is carried out under an inert atmosphere, such as nitrogen gas, argon gas, or helium gas.

The term “self-assembly” refers to a process in which a disordered system of pre-existing components forms an organized structure or pattern as a consequence of specific, local (physical and/or chemical) interactions among the components themselves without the requirement of external direction.

The term “sorption” as used herein refers to a physical and chemical process by which one substance becomes attached to another substance. Absorption and adsorption are examples of “sorption.”

The term “thermoset” as used herein refers to polymer-based solutions that solidify under certain conditions called curing. This process creates a chemical cross-linking that forms an irreversible chemical bond.

The phrase “conventional means” refers to various equipment, equipment or physical arrangements, computer software, computer or physical applications, construction methods, and others that are well known in the art and readily available to accomplish a given set of parameters. Any single technology, arrangement, method, or others that accomplish a specific goal referred to in this document is interchangeable with another so long as the objectives or parameters required by the process described herein can be met (e.g., using either a 100 gallons-per-minute pump with design discharge pressure 90 pounds per square inch and a 120 gallons-per-minute pump with design discharge pressure of 100 pounds per square inch will suffice so long as both the (hypothetical) inlet conditions of 90 gallons-per-minute and 80 pounds per square inch of pressure are met).

Various publications, including patents, published applications and scholarly articles, are cited throughout the specification. Each of these publications is incorporated by reference herein in its entirety.

Porous Carbon Materials

As discussed above, the filtration devices and systems described herein incorporate hierarchically porous carbon materials doped with a metal catalyst having biocidal activity. In particular, the metal catalyst is dispersed on the surface of the carbon phase of the hierarchically porous carbon material. As one having ordinary skill in the art will appreciate in light of the teachings herein, the carbon materials can be made into any number of shapes and sizes depending on their intended use, including being made into chips or pellets or ground into particles or powder. The hierarchically porous carbon materials can be incorporated into water filters, air filters (e.g., HVAC and HEP A filters), respirators, and facemasks as will be described in detail elsewhere herein. Further, the hierarchically porous carbon materials can be formulated as a sprayable powder for easy and cost-effective application to a variety of filter materials to impart to the filter materials increased sorption and biocidal properties.

It is preferred that the carbon materials be porous, /.< ., containing a plurality of small pores or openings, which increase the surface area of the carbon material (or the carbon phase) enabling better sorption and capture of, e.g., droplets and aerosols carrying contagion. Moreover, the expanded surface area of the hierarchically porous carbon materials is particularly useful as a support for metal oxide/metal ions as catalyst materials having biocidal activity. Suitable metal catalysts include, but are not limited to Cu ²⁺ , Co ²⁺ , Cd ²⁺ , Ag, Zn ²⁺ , Mg ²⁺ , Ni ²⁺ , Pt ²⁺ , Mn ²⁺ , copper oxide, zinc oxide, and copper oxide/zinc oxide. The concentration of metal catalyst present in the hierarchically porous carbon material is in the range from about 0.1% by wt to about 30% by wt, e.g, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30% by wt; preferably, the concentration of metal catalyst is between about 1% by wt to about 20% by wt or between about 5% by wt to about 20% by wt. Preferably, the metal catalyst is silver, copper, zinc, copper oxide, zinc oxide, or a combination of copper oxide and zinc oxide. In one particular embodiment, the metal catalyst is zinc, copper, zinc oxide, or copper oxide.

Furthermore, while not intending to be bound by theory, incorporating nitrogen into the carbon backbone of the porous carbon material may further promote or enhance the catalytic activity of the metal catalyst thereby increasing its biocidal properties. As such, in some embodiments, the hierarchically porous carbon material contains a concentration of nitrogen of between about 0.1% by wt and about 30% by wt, e.g., 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30% by wt; preferably, the nitrogen concentration is between about 1% by wt and about 10% by wt; more preferably, the nitrogen concentration is between about 1% by wt and about 3% by wt. For instance, in one particular embodiment, the hierarchically porous carbon material contains about 1% to about 3% by wt nitrogen, or about 1% to about 2% by wt nitrogen, or about 2% by wt nitrogen, or about 3% by wt nitrogen, or about 4% by wt nitrogen. In another embodiment, the hierarchically porous carbon material contains at least about 1% by wt nitrogen, or at least about 2% by wt nitrogen, or at least about 3% by wt nitrogen. Preferably, the nitrogen source is an organic amine in the initial self-assembling feedstock mixture to produce a final product with the nitrogen incorporated into the carbon backbone of the hierarchically porous carbon material. In other embodiments, the hierarchically porous carbon material can be doped with nitrogen after formation as an alternative to using an organic amine in the initial self-assembly reaction or to supplement the nitrogen already incorporated into the backbone of the hierarchically porous carbon material. In yet other embodiments, the hierarchically porous carbon material does not contain nitrogen, or contains a nitrogen content of less than about 1%, e.g., 0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 0.99%. For instance, coconut shell carbon may be used as the porous carbon material, which has a nitrogen content of about 0.4% to about 0.5%. Thus, in low-nitrogen-containing embodiments, the hierarchically porous carbon material embodiments may contain from about 0% to about 10% nitrogen content; preferably, from about 0.4% to about 2% nitrogen content; or from about 1.5% to about 2%; or from about 0% to about 1% nitrogen content.

The ability of the hierarchically porous carbon material disclosed herein to act as an effective capture agent as well as an effective biocidal agent for killing bacteria, viruses, fungi, or other pathogenic particles is not only because of the metal catalyst biocidal activity, but also because of the increased efficiency of the air flow and surface area properties of the carbon structure. First, the hierarchically porous structure of the carbon material itself greatly increases the surface area of the carbon thereby dramatically enhancing both its sorption/filtering properties as well as increasing the available surface area for contacting disease-causing microorganisms in the air/liquid with the metal catalyst biocidal agent dispersed across the surface of the carbon phase of the material. Second, if nitrogen is present in the hierarchically porous carbon material, it is incorporated into the backbone of the carbon structure rather than merely coating the surface.

The term “hierarchically porous structure” of the carbon material refers to the hierarchical arrangement of the various sizes of pores in the surface of the carbon structure. The carbon materials provided herein will have pores, holes, and/or channels that may or may not extend throughout the entire length of the carbon material, which is sometimes referred to as the continuous carbon phase. The pores can also interconnect, resulting in a network of pores or voids that span the material, permitting the flow of liquid or gas into and through the material, /.< ., a continuous phase of pores or voids. The carbon materials can also be described as bi- continuous (i.e., the carbon structures have two or more continuous phases), meaning that both a voids/pore phase and a carbon phase are continuous throughout the structure. As already noted above, it is additionally preferred that the carbon materials also include metal catalysts having biocidal activity for improving the killing of microbes (e.g., bacteria, viruses, and fungi).

The pores of the carbon materials are generally classified as micropores, mesopores, or macropores, depending on the size of the pore opening. The carbon materials provided herein may contain pores of any one or more of these sizes. For instance, in some embodiments, the carbon materials may contain micropores, while in others, the carbon materials may contain mesopores, while in still others, the carbon materials may contain macropores. It is preferred, however, that the carbon materials contain a plurality of macropores and/or mesopores, wherein the walls of the macropores and/or mesopores comprise the continuous carbon phase. In some embodiments, the porous materials will also comprise a plurality of micropores. In a particular embodiment, the carbon support structures comprise hierarchical pores, meaning these structures will contain pores spanning two or more different length scales, e.g., contain both macropores and mesopores. For instance, in an embodiment of a hierarchical pore arrangement, the carbon materials will include a plurality of macropores, the walls of which will comprise a plurality of mesopores. Moreover, the walls of the macropores and/or mesopores may also comprise a plurality of micropores.

In some embodiments, the carbon structures comprise a plurality of macropores. Macropores are pores or voids having a diameter greater than about 0.05 pm. For example, the macropores can have a diameter greater than about 0.05 pm, greater than about 0.075 pm, greater than about 0.1 pm, greater than about 0.75 pm, greater than about 1.0 pm, greater than about 1.5 pm, greater than about 2.0 pm, greater than about 2.5 pm, greater than about 5 pm, greater than about 10 pm, greater than about 15 pm, or greater. In some embodiments, the macropores have a diameter of less than about 100 pm (e.g., less than about 100 pm, less than about 90 pm, less than about 80 pm, less than about 70 pm, less than about 60 pm, less than about 50 pm, less than about 40 pm, less than about 30 pm, less than about 25 pm, less than about 20 pm, less than about 15 pm, less than about 10 pm, less than about 7.5 pm, less than about 5pm, less than about 2.5 pm, less than about 2.0 pm, less than about 1.5 pm, less than about 1.0 pm, less than about 0.75 pm, less than about 0.5 pm, less than about 0.25 pm, or less).

The macropores can have a diameter ranging from any of the minimum values to any of the maximum values described above. In some embodiments, the macropores have a diameter of from about 0.05 pm to about 100 pm. In certain instances, the macropores have a diameter of from about 0.5 pm to about 30 pm, from about 1 pm to about 20 pm, from about 5 pm to about 15pm, from about 10 pm to about 30 pm, or from about 0.5 pm to about 15 pm in diameter. The macropores can have a substantially constant diameter along their length.

In some embodiments, the diameter of the macropores is substantially constant from macropore to macropore throughout the material, such that substantially all (e.g., at least 75%, at least 80%, at least 85%, at least 90%, or at least 95%) of the macropores in the material have a diameter that is within 40% of the average macropore's diameter (e.g., within 35% of the average macropore's diameter, within 30% of the average macropore's diameter, within 25% of the average macropore's diameter, within 20% of the average macropore's diameter, within 15% of the average macropore's diameter, or within 10% of the average macropore's diameter).

The walls of the macropores are formed from a continuous carbon phase. In some embodiments, the walls have a thickness of from about 50 nm to about 15 pm, for example, from about 50 nm to about 600 nm, from about 100 nm to about 500 nm, from about 200 to about 400 nm, from about 50 nm to about 200 nm, from about 300 nm to about 600 nm, from about 500 nm to about 5 pm, from about 5 pm to about 10 pm, or from about 5 pm to about 15 pm.

In preferred embodiments, the carbon structures comprise a plurality of mesopores. In some embodiments, the carbon structures will comprise a plurality of macropores and the walls of the macropores will comprise a plurality of mesopores, thereby forming a hierarchically porous material.

Mesopores are pores, holes, voids, and/or channels having a diameter ranging from about 2 nm to about 50 nm. For example, the mesopores can have a diameter greater than about 2 nm, greater than about 3 nm, greater than about 4 nm, greater than about 5 nm, greater than about 7.5 nm, greater than about 10 nm, greater than about 15 nm, greater than about 20 nm, greater than about 25 nm, greater than about 30 nm, or greater. In some embodiments, the mesopores have a diameter of less than about 50 nm (e.g., less than about 40 nm, less than about 35 nm, less than about 30 nm, less than about 25 nm, less than about 20 nm, less than about 15 nm, less than about 10 nm, less than about 7.5 nm, less than about 6 nm, less than about 5 nm, or less). For example, the mesopores can have a diameter ranging from about 2 nm to about 30 nm, from about 10 nm to about 20 nm, from about 15 nm to about 50 nm, from about 2 nm to about 6 nm, or from about 2 nm to about 15 nm in diameter.

The mesopores can have a substantially constant diameter along their length. In some embodiments, the diameter of the mesopores is substantially constant from mesopore to mesopore throughout the material, such that substantially all (e.g., at least 75%, at least 80%, at least 85%, at least 90%, or at least 95%) of the mesopores in the material have a diameter that is within 40% of the average mesopore's diameter (e.g., within 35% of the average mesopore's diameter, within 30% of the average mesopore's diameter, within 25% of the average mesopore's diameter, within 20% of the average mesopore's diameter, within 15% of the average mesopore's diameter, or within 10% of the average mesopore's diameter).

The walls of the mesopores are formed from a continuous carbon phase. In some embodiments, the walls have a thickness of from about 5 nm to about 15 pm, for example, from about 5 nm to about 10 pm, from about 5 nm to about 5 pm, from about 5 nm to about 1 m, from about 5 nm to about 800 nm, from about 5 nm to about 600 nm, from about 5 nm to about 500 nm, from about 5 nm to about 400 nm, from about 5 nm to about 200 nm, from about 5 nm to about 10 nm, from about 5 nm to about 50 nm, or from about 5 nm to about 25 nm. In some instances, the walls have a thickness of greater than 5 nm (e.g., greater than 10 nm, greater than 15 nm, greater than 20 nm, or greater).

In some embodiments, the carbon structures comprise a plurality of micropores. In some embodiments, the walls of the macropores, mesopores, or combinations thereof further contain micropores. Micropores are pores, holes, and/or channels that have a diameter of less than about 2 nm. For example, micropores can have a diameter ranging from about 0.2 nm to 2 nm. The walls of the micropores can be formed from a continuous carbon phase.

The hierarchically porous carbon materials can be formed by any art-standard batch process or as a continuous process as described in international patent application no. PCT/US2020/049756, the content of which is incorporated by reference herein in its entirety. In some embodiments, the structures can be described as hierarchically porous carbon monoliths that can be subsequently ground into a powder or formed into chips or pellets as described elsewhere herein. Further, the hierarchically porous carbon structures described herein can be characterized as possessing two or more continuous phases (e.g., a void phase and a carbon phase). The two or more phases are generally tortuous, such that the two or more phases are interpenetrating. Moreover, imparting mesopores to the carbon structures enhances sorption kinetics.

Preferably, the pores or openings of the porous carbons structures are formed as a result of the self-assembly and polymerization of organic chemical compounds. For instance, during the polymerization reaction, these chemical compounds in the form of monomers will react with other monomer chemical compounds to form a gel-like suspension consisting of bonded, crosslinked macromolecules with deposits of liquid solution (i.e., sol-gel polymerization) or gas (i.e., aerogel polymerization) between them. In a sol-gel polymerization process, the heat curing and drying steps cause the evaporation of the liquid solution deposits thus leaving behind the crosslinked molecular frame. The resulting heat-cured and dried gel is subjected to pyrolysis. In some embodiments, the cured and dried gel is extruded into carbon structures, such as cylinders or monolith structures, having a diameter of about 1 mm to about 6 mm (e.g. and a length from about 0.1 mm to about 10 mm. Preferably, the average length of a carbon monolith is from about 1 mm to about 6 mm (e.g., 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, or 6 mm). For instance, in one particular embodiment, the average length of a carbon monolith produced herein is about 4 mm. In other embodiments, the extruded material is pulverized or ground into smaller particles and subjected to pyrolysis to produce a carbon powder with particle sizes less than about 1 mm (e.g., 0.9 mm, 0.8, mm, 0.7 mm, 0.6 mm, 0.5 mm, 0.4 mm, 0.3 mm, 0.2 mm, 0.1 mm, or smaller). Suitable grinding equipment include, but not limited to, ball-mills or stationary grinders. In other embodiments, the extruded material is formed into a spherical or bead or pellet shape by extrusion followed by spheronization

As noted above, the pores are formed by a self-assembling polymerization process. As such, the carbon-containing components of the polymerization reaction should be chosen based on their ability to react to form the macromolecular structures with hierarchically porous characteristics. Suitable chemical mixtures for producing the hierarchically porous carbon structures will now be described in more detail.

Polymer Compositions

While hierarchically-porous carbon materials may be produced using a variety of suitable polymer compositions, provided herein are chemical mixtures that comprise organic compounds (i.e., compounds containing carbon-hydrogen bonds) that are capable of self-assembly via polymerization to form the macromolecular carbon material that will be further cured, dried, extruded, and pyrolyzed to produce the hierarchically porous carbon monoliths. As one having ordinary skill in the art would recognize, self-assembly is a process whereby a mixture of components (e.g., chemical compounds) forms an organized structure as a consequence of specific interactions among the components themselves. Typically, these compositions will comprise thermoset mixtures of polymers that crosslink together during the self-assembly process. In some embodiments, the thermosets are highly branched. In further aspects, hierarchically porous carbon monoliths or pellets are provided that comprise, optionally, a nitrogen-containing framework for conferring to the carbon structure improved gas or liquid (e.g., droplets or aerosols) sorption. For instance, amine groups may be introduced into the porous carbon material during the polymerization step. In some embodiments, a sol-gel is provided that is produced by curing (e.g., heat-curing) a self-assembled block co-polymer- phenolic resin gel with the majority of the curing done at the reaction step, which is carried out under heat. In turn, the polymeric sol-gel is processed (dried and pyrolyzed) to produce the hierarchically porous carbon material. The instant disclosure refers to polymeric gels, which may include either sol-gels or aerogels containing polymers.

The self-assembling carbon-containing mixtures will comprise a mixture of chemical compounds capable of undergoing polymerization to form the macromolecular carbon structures. As noted above, it may be desirable to incorporate nitrogen in the carbon backbone of the porous carbon structure. Therefore, in one exemplary embodiment, suitable compositions for selfassembly of a hierarchically porous carbon material may include a mixture of an alcohol (-OH), organic amine (-NH2), and an aldehyde (-CHO) (e.g., formaldehyde), and a carbonyl or aromatic compound. A mixture of these classes of carbon-containing compounds will undergo what is known in the art as a Mannich reaction, which is a reaction commonly used in the art for the construction of nitrogen-containing compounds. In a Mannich reaction, an aldehyde and an organic amine can facilitate the amino alkylation of an acidic proton on a carbonyl functional group or aromatic ring to produce a Mannich base. The resulting Mannich base compound can then be polymerized to form the polymeric solution. It is preferable that these self-assembling mixtures will include an organic amine, an aldehyde, and a carbonyl or aromatic compound. In some embodiments, the self-assembling mixture will additionally contain one or more solvents, such as ethanol, methanol, propanol, glycols, a surfactant, and/or deionized (DI) water.

The component that contains the hydroxyl (‘-OH’) group or aromatic ring can be selected from a variety of suitable compounds, including urea, an imide (e.g., succinimide, mal eimide, glutarimide, phthalimide, and melamine) or a phenol (e.g., benzenediols, such as hydroquinone, and benzenetri ols). For instance, these components can be used to produce polyurea gels (e.g., DESMODUR RE polyisocyanate mixed with water and triethylamine), polyimide gels, and/or block co-polymer-phenolic gels. In a preferred embodiment, a block co-polymer-phenolic gel is produced in a Mannich reaction that includes, inter alia, a phenolic compound. Phenolic compounds suitable for use in the mixture include benzenediols (such as resorcinol, catechol, or hydroquinone) or benzenetri ols. In a particular embodiment, the phenolic compound is a benzenediol, which may be selected from one or more of three benzenediol isomers that include 1,2-benzenediol (ortho-benzenediol or Catechol), 1,3-benezenediol (meta-benzenediol or Resorcinol), or 1,4-benezenediol (para-benzenediol or Hydroquinone). In a particular embodiment, the composition includes the benzenediol, Resorcinol. The amount of the carbonyl/aromatic compound present in the reaction ranges from about 5% wt to about 40 % wt, e.g, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, or 40% wt. Preferably, it is present in the amount of about 5% to about 20% wt. For instance, in one particular embodiment, about 10 % to about 12% by weight Resorcinol was included in the reaction. In another other embodiments, about 6 % to about 14% Resorcinol was included in the reaction.

The Mannich reaction also includes an aldehyde and an organic amine component. Thus, provided herein are reaction mixtures that include one or more organic amines for activating an aldehyde. In this manner, and as opposed to simply coating or doping the surface of a carbon scaffold with a nitrogen-containing material, the nitrogen is incorporated into the backbone of the carbon structure to produce a porous carbon material with nitrogen content of about 0.1% to about 30% by wt, e.g., 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30% by wt; preferably, between about 1% by wt and about 10% by wt; more preferably, between about 1% by wt and about 3% by wt or between about 1% by wt and about 2% by wt. Preferably, the organic amine is a protic amine, e.g., a primary or secondary amine. Suitable organic amines for use in a Mannich reaction for production of the self-assembled polymeric gel in the process provided herein include, but are not limited to, amino acids (e.g., L-lysine), melamine, pyrrolidine, polyvinyl pyrrolidine (PVP), 1,6-diaminohexane (DAH), ethylenediamine (EDA), 4-dimethyl amino pyridine (4-DMAP), and dimethylamine (DMA). For instance, in one particular embodiment, DAH or lysine was chosen as the primary amine. The amount of the amine present in the Mannich reaction ranges from about 0.01 % wt to about 40 % wt, e.g., 0.01%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, 30%, 35%, or 40% wt. Preferably, it is present in the amount of about 0.1% to about 5% wt. For instance, in one particular embodiment, about 1.3 % to about 1.6 % by weight DAH is present in the reaction. In another embodiment, the amount of DAH present in the polymer feedstock reaction is between about 0.2% to about 0.4% by wt, or between about 0.7% to about 1% by wt, or between about 2 % to about 2.5% by wt, or between about 2.6 % to about 3.1 % by wt (see, for example Table 1). In another embodiment, about 0.6% to about 0.7% by weight lysine is present in the reaction.

The reaction composition will also include an aldehyde. Suitable aldehydes include, formaldehyde (e.g., formalin), benzaldehyde, branched and straight butyraldehyde, or an aldehyde-forming compound such as trioxane. The aldehyde can be added to initiate the selfassembly reaction - either all at once or in-line as the reaction proceeds. The amount of the aldehyde present in the reaction ranges from about 1% wt to about 30 % wt, e.g., 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30% wt. Preferably, it is present in the amount of about 10% to about 20% wt. For instance, in one particular embodiment, about 16% to about 17% by weight formaldehyde is present in the reaction.

While not intending to be bound by theory, the proportion of mesopores in the hierarchically porous carbon structure may be influenced by the molar quantity of amine in relation to the carbonyl or aromatic compound. As the molar ratio of amine to carbonyl/aromatic compound increases, the reaction rate increases and, at some point, the reaction time becomes too rapid resulting in the loss of mesopore structure. Therefore, it may be desirable in some embodiments to include in the reaction mixture a ratio of carbonyl or aromatic compounds to amines that favors the production of mesopores. Thus, in particular embodiments, the molar ratio of carbonyl/aromatic compound to amine in the reaction mixture or feedstock will be from about 1 : 1 to about 150: 1. In some embodiments, a greater proportion of mesopores to micropores are preferred and, as such, the molar ratio of carbonyl/aromatic compound to amine in the reaction mixture or feedstock will be from about 5 : 1 to about 100 : 1 , e.g. , about 5: 1, 6: 1, 7: 1, 8: 1, 9: 1,

10: 1, 11 : 1, 12: 1, 13: 1, 14:1, 15: 1, 16: 1, 17: 1, 18: 1, 19: 1, 20: 1, 21 : 1, 22: 1, 23: 1, 24: 1, 25: 1, 26: 1,

27: 1, 28: 1, 29: 1, 30: 1, 31 :1, 32: 1, 33: 1, 34: 1, 35: 1, 36: 1, 37: 1, 38: 1, 39: 1, 40: 1, 41 : 1, 42: 1, 43: 1,

44: 1, 45: 1, 46: 1, 47: 1, 48:1, 49: 1, 50: 1, 60: 1, 70: 1, 80: 1, 90: 1, or 100: 1. In a more preferred embodiment, the molar ratio of carbonyl/aromatic compound to amine in the reaction mixture or feedstock will be from about 20:1 to about 50: 1. For instance, in one non-limiting embodiment, the molar ratio of carbonyl/aromatic compound to amine in the reaction mixture or feedstock is about 40: 1 (e.g., Resorcinol to DAH).

In some embodiments, the reaction composition further comprises one or more surfactants to serve as soft-templates to facilitate self-assembly of the carbon-containing polymers. Suitable surfactants may include ionic or non-ionic surfactants, including, but not limited to poloxamers (e.g., PLURONIC L64, PLURONIC Pl 23, PLURONIC Fl 27, and PLURONIC Fl 08) that can be used as non-ionic surfactants and cetyl trimethyl ammonium bromides (CTABs), steartrimonium bromides (STABs), tetradecyltrimethylammonium bromides (TTABs), cetyltrimethylammonium chlorides (CTACs), and lauryltrimethylammonium bromides (LTABs). Poloxamers are hydrophilic, nonionic copolymer surfactants composed of a central hydrophobic chain of polypropylene oxide) flanked by poly(ethylene oxide) chains. Poloxamers used in the reaction composition may have a molecular mass from about 1,000 g/mol to about 20,000 g/mol and a poly(ethylene oxide) content in the range from about 10% to about 80%. For instance, in one exemplary composition, poloxamer 407 is used (about 12,500 g/mol and about 70% poly(ethylene oxide) content). Ionic surfactants suitable for use herein include CTABs with varying chain lengths like, such as CisTAB and CuTAB. While not intending to be bound by theory, it is believed that the interaction between the surfactant and the amine component help induce the self-assembly of the mesostructures in the carbon monolith. Therefore, it may be desirable in some embodiments to include in the reaction mixture a ratio of amine to surfactant that favors the production of mesopores. In some embodiments, the molar ratio of amine to surfactant in the reaction mixture or feedstock will be from about 1 : 1 to about 200: 1, e.g., about 1 : 1, 2: 1, 3: 1, 4: 1, 5: 1, 6: 1, 7: 1, 8: 1, 9: 1, 10: 1, 15:1, 20: 1, 25: 1, 30: 1, 35: 1, 40: 1, 45: 1, 50: 1, 55: 1, 60: 1, 65: 1, 70: 1, 75: 1, 80:1, 85: 1, 90: 1, 95: 1, 100:1, 110: 1, 120: 1, 130: 1, 140: 1, 150: 1, 160: 1, 170: 1, 180: 1, 190: 1, or 200: 1. In a more preferred embodiment, the molar ratio of amine to surfactant in the reaction mixture or feedstock will be from about 2: 1 to about 75 : 1. For instance, in one non-limiting embodiment, the molar ratio of amine to surfactant in the reaction mixture or feedstock is about 6.8: 1 (e.g., DAH to poloxamer 407).

The production of hierarchically porous carbon material with different concentrations of nitrogen incorporated into the carbon backbone can be achieved by varying the amount of organic amine in the polymer composition. A summary of non-limiting exemplary formulations suitable for producing about 70 to about 80 grams of hierarchically porous carbon material extrudates (following pyrolysis) with different concentrations of nitrogen (approximate) is provided in Table 1.

Table 1: Exemplary Formulations with Varying Final Nitrogen Content

In other embodiments, a pore-forming solid may be added to the mixture as an alternative or in addition to the surfactant component. As one having ordinary skill in the art will recognize, pore-forming solids can function as a seed for nucleation of the self-assembling polymer structure. Suitable pore-forming solids include, but are not limited to, silica beads, wax beads, and Styrofoam beads. It may also be desirable to add a binding agent for the shaping/extrusion step. In one particular embodiment, activated carbon is used as the binding agent.

As noted above, the various mixtures of chemical compounds described herein are mixed to form the organic polymeric solution. However, to produce the desired porous carbon materials suitable as a support for the metal catalyst and for use in a biocidal filtration system, the polymeric solution that results from the self-assembly must still be cured to harden the structure, dried to remove the solvent deposits leaving behind macropores, mesopores, and/or micropores, formed to the desired shape, and pyrolyzed to form the final product. In some embodiments, the shaping of the final product can be performed via a stamp-molding step as part of a batch process. In a preferred embodiment, in order to create a continuous process, the stamp-molding step can be replaced with an extrusion step. However, this requires modification of the drying step followed by the extrusion step. Further still, a reactor, such as a plug-flow reactor or tube-in- tube heat exchanger may be incorporated into a continuous process to provide for efficient reaction conditions allowing for self-assembly and the initiation of curing of the polymeric gel material.

As discussed in detail below, the hierarchically porous carbon material can be formed into any desired shape and, if desired, pelletized to form pellets. The hierarchically porous carbon monoliths, chips, or pellets are then pyrolyzed. The pyrolyzed hierarchically porous carbon is then further activated by treatment with an acid (e.g., nitric acid, hydrochloric acid, sulfuric acid, phosphoric acid, and citric acid) alone or in the presence of heat, a base (e.g., sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium carbonate, potassium carbonate, ammonium carbonate, ammonia gas), or steam. Once the hierarchically porous carbon material is pyrolyzed, it can be further ground into a powder. The hierarchically porous carbon monoliths, chips, pellets, or powder is then doped with a metal catalyst to impart the biocidal activity to the carbon structure.

The manufacturing process will now be described in greater detail.

Exemplary Manufacturing Process

While the reaction, heating, curing, shaping, and pyrolysis steps can be performed using any number of suitable synthesis techniques known in the art, such as the methods described in U.S. Patent No. 9,669,388, Hao et al. [“Structurally Designed Synthesis of Mechanically Stable Poly(benzoxazine-co-resol)-Based Porous Carbon Monoliths and Their Application as High Performance CO2 Capture Sorbents” JACS 133 : 11378-11388 (2011)]; Lu et al. [“Porous Carbons for Carbon Dioxide Capture” in Green Chemistry and Sustainable Technology Ch. 2, pp. 15-77 (2014)], the entire contents of each of which are incorporated by reference herein, in one particular exemplary embodiment, a continuous process for manufacturing hierarchically porous carbon materials is described. The source of carbon for creating the carbon structures is provided by combining organic compounds capable of self-assembly. In general, this process may include steps for mixing, reacting, drying, extruding, reducing the size of the product, pyrolysis, production of powder (optional), acid activation, and incorporation of metal catalyst to produce hierarchically porous carbon materials with biocidal activity from an organic feedstock. Figure 1 depicts a graphical representation of the process overview.

In general, the mixing step includes the mixture of carbon-containing compounds in the appropriate ratios and the appropriate conditions in a vessel using art-standard and conventional means. Suitable polymer compositions are described in greater detail elsewhere herein. In a preferred embodiment, the polymeric compositions are thermoset mixtures of organic compounds capable of crosslinking during self-assembly. In some embodiments, the organic polymer compositions are highly branched, crosslinked, thermoset polymeric mixtures. In general, all components are added in the mixing step, with the exception of the initiator, which can be added after the initial mixing step and immediately prior to the beginning of the reacting step to initiate the self-assembly reaction. In some embodiments, a binding agent, such as activated carbon can be added to the mixture of compounds to improve the binding of the dried polymeric gel when extrusion is used for the shaping and sizing of the dried polymeric gel. In addition, a suitable solvent, a soft template, such as a surfactant, and/or a pore-forming solid may be added to the mixture. All materials (except the initiator) can be introduced in any order to the mixing vessel by any conventional means desired by the operator. The components may be mixed until they reach a phase-homogeneous state.

The resulting carbon-containing mixture from the mixing step is then transported to a reactor (e.g., a plug flow reactor or a tube-in-tube heat exchanger) by conventional means. Typically, an initiator (e.g., formalin) is injected into reaction at this step to facilitate the self-assembly of the carbon polymer mixture. The reaction is allowed to occur for a pre-determined period of time and at the appropriate temperature such that the reactants harden into a semi-dry material (e.g., a cured polymeric gel). As noted above, the self-assembling polymeric gel is heat-cured. The majority of the curing occurs during the reaction step. In some embodiments, at least about 60% to about 90%, e.g., 60%, 65%, 70%, 75%, 80%, 85%, or 90%, or more of the polymeric gel is cured in the reaction step. For the drying step, the polymeric gel is introduced into a vessel capable of removing excess liquids (e.g., solvents, water, etc.). Moreover, the drying step substantially completes the curing of the polymeric gel. This vessel will typically consist of a mechanism for solvent removal as a vapor, as a phase-separated liquid, or both. This vessel can be equipped with agitators, vacuum pumps, above-ambient pressure capabilities, various nozzle geometries, or all of the above to accomplish the goal of liquid removal. The removed material may be re-used in the process, thermally decomposed, or otherwise discarded as waste. The dried polymeric gel is then shaped and formed into a specific geometry prior to pyrolysis, such as, but not limited to chips, monoliths, pellets, and the like. The material can be shaped into any geometry desired using conventional means or standard techniques known in the art, such as, but not limited to extrusion, pour molding, injection molding, casting, and the like.

The next step typically utilizes pyrolysis to process the cured, dried, and shaped product. For pyrolysis, the material should be transported as soon as possible to equipment or device(s), such as, but not limited to, a kiln, oven, furnace, or chamber suitable and configured for heating the material in the absence of oxygen to a temperature of greater than about 500 °C for a period of time sufficient for carbonization of the material. This step, in particular, removes all remaining (unreacted) substances with the exception of carbon to result in a hierarchically porous carbon material. The removed material may be collected and re-used in this process, thermally decomposed, or otherwise discarded as waste.

The hierarchically porous carbon material can be further activated by chemical means, such as treatment with acid, base, or steam. In a preferred embodiment, acid treatment is used to further activate the hierarchically porous carbon material, either at the end of the pyrolysis step (z.e., by flowing acid into the pyrolysis chamber) or following completion of the pyrolysis step. Suitable acids include nitric acid, sulfuric acid, phosphoric acid, citric acid, and hydrochloric acid. In one particular embodiment, 2 M nitric acid is used to further activate the hierarchically porous carbon material.

In certain embodiments, the pyrolyzed hierarchically porous carbon material can then be ground into smaller particles to produce a carbon powder with particle sizes less than about 1 mm using, for example, a ball-mill or stationary grinder. After pyrolysis, the hierarchically porous carbon material in monolith, chip, pellet, or powder form is doped with metal or metal oxide nanoparticles (e.g. , of Cu ²⁺ , Co ²⁺ , Cd ²⁺ , Ag ⁺ , Zn ²⁺ , Mg ²⁺ , Ni ²⁺ , Pt ²⁺ , Mn ²⁺ , copper oxide, zinc oxide, or copper oxide/zinc oxide). The nanoparticles are dispersed on the carbon phase of the hierarchically porous carbon, which serves as a solid support for the nanoparticles.

Shown in Figure 2 is a representation of the continuous production process that includes a mixing tank (TK-1) 20, continuous reactor (RX-1) 30, a drying device (OV-1) 40, a shaping/forming device (EX-1) 50, and a pyrolysis device (RX-2) 60. The process will now be described in further detail.

Mixing

As noted above, the process begins with a mixing step where a feedstock containing the desired reaction components is mixed in a suitable mixing vessel for a predetermined time and at a predetermined temperature. In an embodiment, the feedstock is a thermoset polymeric mixture capable of self-assembly in the presence of an initiator and when subjected to an appropriate reaction temperature and residence time. In a particular embodiment, the feedstock is capable of self-assembling into a highly-branched, crosslinked, thermoset polymeric gel containing carbon. Suitable mixing vessels include any conventional vessel or means known in the art for mixing components, such as a mixing tank. In a preferred embodiment, all non-reacting components of the polymer composition are added to the mixing vessel, with the exception of the initiator, which is preferably held out until after the components are mixed to a phase-homogeneous end state at a desired temperature. In some embodiments, the vessel can first be agitated lightly to encourage mixing after the initial addition of the nonreacting components after which the mixing can be halted and restarted as needed without having an adverse effect on the polymer composition.

Shown in Figure 2 is a mixing step that includes a mixing tank (TK-1) 20 wherein a suitable feedstock of non-reacting components is mixed for a predetermined time in the range from about 1 minute to about 5 hours, or more, e.g., about 1 minute, 5 minutes, 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 35 minutes, 40 minutes, 45 minutes, 50 minutes, 55 minutes, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, or more. Suitable mixing temperatures range from about 10 °C to about 50 °C, e.g., about 10 °C, 15 °C, 20 °C, 25 °C, 30 °C, 35 °C, 40 °C, 45 °C, or 50 °C.

As discussed herein, the feedstock composition will be capable of self-assembly via polymerization. Suitable self-assembly polymer compositions include, but are not limited to, a mixture of an alcohol, an organic amine, an aldehyde, and a carbonyl or aromatic compound. In some embodiments, the compositions further include a surfactant, solvent, pore-forming solid, and/or a binding agent. In a preferred embodiment, the aldehyde is held out of the mixture until just prior to the reacting step. As summarized in Figure 2, once the feedstock mixture has reached a phase homogeneous end state (e.g., fully dissolved in solution) at a desired temperature, e.g., about 10 °C to about 50 °C, the material is then transported to the continuous reactor (RX-1) 30 via transporter member 22, which can be a conventional or art-standard transporter such as, but not limited to, belt conveyer, pneumatic conveyor, pipe, tube, or pump (e.g., vacuum pump or peristaltic pump). Once the phase-homogeneous feedstock mixture is in the continuous reactor (RX-1) 30, the reaction can be initiated.

Reacting

The reacting step includes initiating the self-assembly reaction of the polymer solution with the addition of an initiator compound. As one having ordinary skill in the art would appreciate, the identity of the initiator compound typically depends on the particular composition being self-assembled. For instance, in one embodiment, the initiator compound is an aldehyde, such as formalin or formaldehyde. The reaction of the phase-homogeneous mixture with the initiator is typically carried out in a reactor. For the reaction to take place, time at the appropriate temperature is required in order to harden the reactants into a semi-dry material (or gel). Moreover, as noted above, the majority of the curing is completed during the reaction step. In a preferred embodiment, the reactor is a plug-flow type reactor or a tube-in-tube heat exchanger of sufficient length. Other suitable reactors may include a tube-in-shell heat exchanger.

These types of reactors can be built from conventional piping or tubing (e.g., steel, rubber, or plastic) or can be adapted from commercially available piping or tubein-tube heat exchangers. In one embodiment, a reactor may be used and held at one or more temperatures (e.g., zones) to allow for the reaction to take place and product gel to form. For instance, the reactor can be adapted to apply one or more temperature zones along its length such that as the self-assembling reactant mixture is flowed through the piping, it is exposed to different temperatures. In one embodiment, the reactor has one temperature zone in the range from about 40 °C to about 130 °C, e.g., 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, 125 °C, or 130 °C. In some embodiments, the reaction temperature is from about 60 °C to about 100 °C, or from about 75 °C to about 85 °C. For instance, in one embodiment, the self-assembling mixture includes a phenolic compound, surfactant, alcohol, amine, and aldehyde and the reaction temperature is from about 60 °C to about 120 °C. In a particular embodiment, the reaction temperature is about 120 °C. In another particular embodiment, the reaction temperature is 80 °C to 82 °C. In another embodiment, the reactor has two or more temperature zones, each of which is in the range from about 40 °C to about 130 °C, e.g., 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, 125 °C, or 130 °C. In such embodiments, the temperature zones can each be at different temperatures. The length of the reactor piping/tubing may vary depending on the scale of the production and the number of temperature zones desired. The length of the reactor is typically at least about 1 ft to about 100 ft, e.g. , 1 ft, 5 ft, 10 ft, 15 ft, 20 ft, 25 ft, 30 ft, 35 ft, 40 ft, 45 ft, 50 ft, 55 ft, 60 ft, 65 ft, 70 ft, 75 ft, 80 ft, 85 ft, 90 ft, 95 ft, or 100 ft. While the optimal length of the reactor will vary with temperature, in a particular embodiment, a reactor with a temperature zone at about 75 °C to about 85 °C or about 100 °C to about 120 °C is preferably about 50 ft. There may be multiple heating (or cooling) zones depending on the specific conditions necessary for each discreet formulation to react, self-assemble, cure, dry or extrude in the reactor. One or all of these unit operations may be performed in the primary reactor or in sequentially connected equipment designed for the purpose of performing these steps.

Sufficient residence time of the mixture in the reactor is required to ensure that the self-assembling reaction mixture has polymerized to a semi-hardened, gel-like material. As noted above, about 60% to about 90%, or more; preferably, about 80% to about 90% of the polymeric gel is cured in the reaction step. The selection of residence time will depend on various factors, such as temperature, pressure, polymeric composition, and the like and it is well within the purview of the skilled artisan to optimize the residence time parameters. Typical residence time is in the range from about 1 minute to about 120 minutes, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, or 120 minutes. In a preferred embodiment, the residence time is in the range from about 1 minute to about 60 minutes. In a more preferred embodiment, the residence time is in the range from about 1 minute to about 10 minutes or about 5 minutes to about 10 minutes.

In some embodiments, the reactor is held at a specific pressure, which can be measured at any given point along the reactor and held constant by way of manipulating equipment or process parameters in order to keep all reactants in the liquid state. The pressure of the system may be in the range from about 0 psi to 100 psi, preferably, from about 0 psi to about 15 psi. In other embodiments, static mixers or agitation is used to prevent the solution from phase separating.

As shown in Figure 2, the phase-homogeneous mixture is transported from the mixing tank (TK-1) 20 to the continuous reactor (RX-1) 30 by way of the transporter member 22. In the particular embodiment depicted in Figure 2, the continuous reactor (RX-1) 30 is a plug-flow reactor. As the phase-homogeneous mixture is fed into the continuous reactor (RX-1) 30, the initiator (e.g., formalin or trioxane) 24 is added to the mixture (e.g., in-line injector 26) to initiate the self-assembly reaction. In this particular embodiment, the reaction components (with initiator) travel through RX-1 30 while being heated to operating temperature in range of about 40 °C to about 130 °C. In some embodiments, the operating temperature is in the range of about 60 °C to about 100 °C.

Drying

Upon exit from the reactor, the self-assembled polymeric gel material proceeds to the drying step by conventional means of transport, such as, but not limited to, belt conveyer, pneumatic conveyor, pipe, tube, or pump (e.g., vacuum pump or peristaltic pump). For the drying step, the polymeric gel is then introduced into a vessel or vessels capable of removing excess liquids (e.g., solvents, water, etc.). This vessel(s) will typically consist of a mechanism for solvent removal as a vapor, as a phase- separated liquid, or both. This vessel(s) can be equipped with agitators, vacuum pumps, above-ambient pressure capabilities, various nozzle geometries, or all of the above to accomplish the goal of liquid removal. The removed material may be re-used in the process, thermally decomposed, or otherwise discarded as waste.

During the drying step, the unreacted compound(s) (e.g., the aldehydic compound) and the solvent phase begin to be evaporated off resulting in the formation of dried porous polymeric gel phase. In some embodiments, the polymeric gel is dried at a temperature in the range from about 40 °C to about 150 °C, e.g., 40 °C, 45 °C, 50 °C, 55 °C, 60 °C, 65 °C, 70 °C, 75 °C, 80 °C, 85 °C, 90 °C, 95 °C, 100 °C, 105 °C, 110 °C, 115 °C, 120 °C, 125 °C, 130 °C, 135 °C, 140 °C, 145 °C, or 150 °C for a time period of about 1 minute to about 15 hours or more, e.g., about 1 minute, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, or more. In one embodiment, the drying temperature is from about 75 °C to about 140 °C; in another embodiment, the temperature is about 100 °C to about 130 °C. Furthermore, the drying time can be as short as about 1 minute to about 10 minutes, or about 5 minutes to about 10 minutes. In a particular embodiment, the cured polymeric gel is dried at a temperature in the range from about 45 °C to about 60 °C for about 5 hours to about 12 hours. In another embodiment, the cured polymeric gel is dried at a temperature of about 120 °C for about 5 minutes to 10 minutes. In another particular embodiment, the cured polymeric gel is dried at a temperature in the range from about 75 °C to about 85 °C for a period of about 5 minutes to about 30 minutes. As noted above, in a preferred embodiment, the curing of the polymeric gel is substantially completed in the drying step.

The drying may be performed in art standard drying equipment/vessels. In a particular embodiment, a devolatilizing extruder is used in combination of varying temperatures and pressures to achieve liquid removal. Liquid is removed as a vapor by lowering pressure and/or elevating temperature in specific zones of the extruder that are specially designed for this operation.

Figure 2 depicts the drying of the output material that is transported from the reactor RX-1 30 to the drying device OV-1 40 via transporter member 32, which can be a conventional transporter (e.g. , belt conveyer, pneumatic conveyor, pipe, tube, or pump). Once in the OV-1 40, the unreacted aldehydic compound and the solvent phase begin to be evaporated off (i.e., solvent removal 35) resulting in the formation of dried porous polymeric gel phase. The drying step may be performed in the OV-1 40, at a temperature in the range from about 40 °C to about 140 °C for a time period of about 1 minute to about 10 hours or more. In particular embodiment, the drying is performed in the OV-1 40 at a temperature in the range from about 75 °C to about 85 °C for a period of time of about 5 minutes to about 30 minutes. In another particular embodiment, the drying is performed in the OV-1 40 at a temperature of about 120 °C for about 5 to 10 minutes.

In other embodiments, additional drying may be performed before or after the extruder (z.e. , the sizing/forming step) to further remove volatiles (e.g., solvent removal 35’) or harden the material. In one embodiment, this may be performed with a continuous oven, tunnel or other system designed for time and temperatures appropriate for processing of the extrudates.

Sizing/Forming

In this step, the cured and dried polymeric gel is shaped and formed into a specific geometry prior to pyrolysis. The material can be shaped into any geometry and size desired using art-standard techniques, such as extrusion, pour molding, inj ection molding, casting, extrusion-spheronization, pelletization, and the like. This step may be performed under various temperatures or pressures or a range of both.

In one embodiment, an extruder is utilized to form the material. An extruder applies hydraulic force to a material along a longitudinal axis by forcing the material against a die face at the end of a chamber. The die of the extruder is fashioned to provide backpressure on the auger(s) of the extruder and also to force the material into the desired dimension and/or geometries. For instance, in a particular embodiment, the hierarchically porous carbon material is in the shape of a cylinder. The material exiting the extruder is then cut at a specific time to achieve the specific shapes desired. Exemplary extruders include, but are not limited to, screw extruders (e.g., single or twin extruders, axial/radial-type extruders), continuous Sev extruders, food extruders, sieve extruders, basket extruders, roll extruders (e.g., one/two/rotating perforated roll extruders), ram extruders, pressure extruders, hydraulic extruders, or devolatilizing extruders. For instance, in a particular aspect, the extruder is a devolatilizing extruder configured to cure the polymeric gel and dry the cured polymeric gel, and the like. The die of the extruder may be selected from any size and shape to give the extruded gel the desired shape and diameter. In an embodiment, the die aperture is a rectangle, square, triangle, hexagon, star, hollow tube, or circle. Moreover, the diameter of the die aperture can be from about Im to about 10mm, e.g. , 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm.

In another embodiment, the polymeric gel is shaped and formed into a spherical or bead or pellet shape by extrusion followed by spheronization. For instance, the sizing/forming step may include an extruder and a pelletizer that is attached to a spheronizer (such as a Marumizer spheronizer) for spheronizing the extruded polymer.

In Figure 2, the dried polymeric gel is fed into the sizing and forming equipment EX-1 50 by transporter member 42, which can be a conventional means of transporter. In this embodiment, EX-1 50 is an extruder, such as a devolatilizing extruder, of sufficient capacity and function to shape the extrudate into the desired shapes with the desired dimensions. This extruder may include temperature and pressure controls for the precise control of the temperature and pressure in portion of the extruder and/or throughout the entire extruder. For instance, the extruder may be specifically designed to remove liquids from the denser, extrudable material. In some embodiments, the extruder can perform both temperature/pressure control and liquid removal. In this embodiment, the polymeric solution is transported from the output of OV-1 40 to EX-1 50 by transporter means 42 utilizing pressure. Once the polymeric gel is extruded and sized, it is conveyed or otherwise fed into the pyrolysis furnace.

In another embodiment, both the drying and extrusion step is performed in the extruder, such as in a devolatilizing extruder, of sufficient capacity and function to shape the extrudate into the desired shapes with the desired dimensions. As such, the polymeric gel is dried and fully cured by the completion of the extrusion process.

Pyrolysis

Following extrusion, the extruded polymeric gel is subjected to high heat for the production of the carbon monolith/pellets/extrudates/beads. While the process provided herein encompasses the use of combustion and/or pyrolysis to administer the high heat to be applied to the extruded polymeric gel to produce the final porous carbon materials, it is preferable to utilize pyrolysis. The flow of inert gases may be used to produce an inert atmosphere that favors pyrolysis over combustion at high temperatures. For instance, in an embodiment, the flow of inert gas, such as nitrogen gas, argon gas, or helium gas, may be used to maintain an inert atmosphere within a kiln or furnace during pyrolysis. Suitable equipment/devices for pyrolysis include kilns, ovens, furnaces, or pyrolysis chambers known in the art. In a particular embodiment, a specially designed furnace is used that can vary temperature, pressure, and residence time within the furnace to accomplish the pyrolysis.

For the pyrolysis step, the extruded polymeric carbon gel material should be transported as soon as possible to equipment or device(s) designed for the purpose of heating the material in the absence of oxygen to a temperature of greater than 500 °C, e.g., 501°C, 510 °C, 520 °C, 530 °C, 540 °C, 550 °C, 560 °C, 570 °C, 580 °C, 590 °C,

600 °C, 610 °C, 620 °C, 630 °C, 640 °C, 650 °C, 660 °C, 670 °C, 680 °C, 690 °C, 700

°C, 710 °C, 720 °C, 730 °C, 740 °C, 750 °C, 760 °C, 770 °C, 780 °C, 790 °C, 800 °C,

810 °C, 820 °C, 830 °C, 840 °C, 850 °C, 860 °C, 870 °C, 880 °C, 890 °C, 900 °C, 910

°C, 920 °C, 930 °C, 940 °C, 950 °C, 960 °C, 970 °C, 980 °C, 990 °C, 1,000 °C, 1,050 °C, 1, 100 °C, 1, 150 °C, 1,200 °C, 1,250 °C, 1,300 °C, 1,350 °C, 1,400 °C, or greater, until the material is fully carbonized. Preferably, the temperature is in the range from about 500 °C to about 1,300 °C; more preferably, between about 600 °C and 1,000 °C. For instance, in one particular embodiment, the temperature for pyrolysis is about 800 °C. In another embodiment, the temperature for pyrolysis is as high as about 1,200 °C.

The residence time for pyrolysis can range from about 10 minutes to about 14 hours, e.g., 10 minutes, 15 minutes, 20 minutes, 25 minutes, 30 minutes, 45 minutes, 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, 3.5 hours, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, 10.5 hours, 11 hours, 11.5 hours, 12 hours, 12.5 hours, 13 hours, 13.5 hours, or 14 hours. In a preferred embodiment, the residence time is about 1 hour to about 12 hours. This step, in particular, removes all remaining substances with the exception of carbon to result in a hierarchically porous carbon material. The removed material may be collected and re-used in this process, thermally decomposed, or otherwise discarded as waste.

As represented by Figure 2, the extruded polymeric gel is transported from EX-1 50 to the pyrolysis furnace RX-2 60 via conventional transporter member 52. Pyrolysis furnace RX-2 60 is utilized to pyrolyze the cured and dried extrudates. In the embodiment shown in Figure 2, the pyrolysis furnace RX-2 60 is maintained in the absence or near absence of oxygen (or other oxidant gases) to prevent combustion. In this embodiment, the extrudate is pyrolyzed under nitrogen gas at a temperature of about 800 °C with a residence time of about 10 hours.

In some embodiments, the hierarchically porous carbon material produced by the pyrolysis step can be in the form of a monolith. In other embodiments, the hierarchical porous carbon material produced by the pyrolysis step can be cut or ground into any desirable shape or form. For instance, the pyrolyzed carbon material can be ground up into small particles of less than about 0.1 mm in diameter (e.g., a powder).

Following pyrolysis, the hierarchically porous carbon can be further activated by acid, base, or steam treatment. Suitable acids include, but are not limited to, nitric acid, phosphoric acid, sulfuric acid, hydrochloric acid, and citric acid. For instance, 2 M nitric acid can be used to activate the pyrolyzed hierarchically porous carbon material. In some embodiments, acid can be flowed into the pyrolysis chamber during the end of the pyrolysis process. In other embodiments, the acid treatment is performed after pyrolysis is complete. In yet other embodiment, the acid treatment is performed under heat.

Addition of Metal Catalyst

The final step in the process involves doping of the pyrolyzed hierarchically porous carbon material with metal or metal oxide catalysts with biocidal activity, which can be performed as part of the continuous process above or performed separately. Hierarchically porous carbon material in the form of monoliths, chips, or pellets are preferably doped with metal or metal oxide catalysts in the form of nanoparticles according to the method described in U.S. Patent No. 9,669,388, the entire contents of which is incorporated by reference herein. The metal-containing nanoparticles can be evenly dispersed throughout the hierarchically porous carbon material such that the distance between adjacent particles deposited on the carbon phase is relatively constant. In a preferred embodiment, the discreet nanoparticles are evenly dispersed in the walls of the macropores and mesopores. As noted above, the nanoparticles are formed from a catalytically active metal or metal oxide with biocidal properties including, but not limited to, Cu ²⁺ , Co ²⁺ , Cd ²⁺ , Ag ⁺ , Zn ²⁺ , Mg ²⁺ , Ni ²⁺ , Pt ²⁺ , Mn ²⁺ , copper oxide, zinc oxide, copper or oxide/zinc oxide. The concentration of metal catalyst present in the hierarchically porous carbon material is typically in the range from about 0.1% by wt to about 30% by wt, e.g., 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30% by wt; preferably, the concentration of metal catalyst is between about 1% by wt to about 20% by wt or about 5% by wt to about 20% by wt. Preferably, the metal catalyst is silver, copper oxide, zinc oxide, or a combination of copper oxide and zinc oxide.

The metal salt can be used in solution, hydrate or solvent form, or neat. This can be accomplished by contacting the porous carbon material with the metal salt at above the salt’s melt temperature, but below the salt’s decomposition temperature. Alternatively, the metal salt can be part of a solution comprising the metal salt and a solvent. It is preferable that the metal salt include a metal ion with biocidal properties, such as of Cu ²⁺ , Co ²⁺ , Cd ²⁺ , Ag ⁺ , Zn ²⁺ , Mg ²⁺ , Ni ²⁺ , Pt ²⁺ , or Mn ²⁺ . The counterion of the metal salt can be a nitrate, acetate, sulfate, chloride, carbonate, bromide, iodide, phosphate, sulfite, phosphite, or nitrite. Suitable solvents include, but are not limited to alcohols, polyols, carboxylic acids, esters, aldehydes, ketones, and the like. The weight or molar ratio of metal salt to solvent can be from about 1 : 1000 to about 10: 1, e.g., 1 : 1000, 1 :750, 1 :500, 1 :250, 1 :200, 1 : 150, 1 : 100, 1 :75, 1 :50, 1 :40, 1 :30, 1 :25, 1 :20, 1 : 15, 1 : 10, 2: 10, 3: 10, 4: 10, 5: 10, 6:10, 7: 10, 8: 10, 9: 10, 10:9, 10:8, 10:7, 10:6, 10:5, 10:4, 10:3, 10: 1, or 1 : 1.

The hierarchically porous carbon material is generally contacted with a composition comprising a metal salt or metal oxide at a reduced pressure (e.g., with the use of a vacuum) to remove all air from the template and dissolved gases from the metal salt solution can produce an even spatial distribution of the metal salt and, consequently, metal nanoparticles throughout the porous carbon material. Once the spatial distribution of the metal salt in the porous template is attained, the metal salt is then reacted to form discrete nanoparticles evenly distribute in the carbon phase. The metal salt may be reacted by any art-standard method, such as with a reducing agent, with heat, addition of a supercritical fluid, and the like.

Metal oxide nanoparticles, including, but not limited to copper oxide, zinc oxide, or a combination of copper oxide and zinc oxide, can be formed by contacting the metal salt with an oxidizing agent, such as an oxidizing atmosphere or gas (e.g., oxygen, air, carbon dioxide, and the like). Hierarchically porous carbon material in powder form can be doped with metal or metal oxide catalysts according to art-standard techniques. In one embodiment, the pyrolyzed hierarchically porous carbon material can then be ground into smaller particles to produce a carbon powder with particle sizes less than about 1 mm (preferably, less than about 0.5 mm or less than about 0.1 mm) using, for example, a ball-mill or a stationary grinder. The hierarchically porous carbon powder is then contacted with a composition comprising a metal salt or metal oxide such that the metal catalyst infiltrates into the porous carbon material. For example, the incipient wetness impregnation method can be performed using a metal precursor, such as copper (II) nitrate trihydrate to dope the surface of the carbon phase with Cu ²⁺ . For instance, in one embodiment, the desired amount of metal salt/metal precursor can be dissolved in suitable solvent, such as deionized water. The amount of metal salt/metal precursor starting material may be about 5-fold to about 10-fold greater than the mass of the carbon powder material. The hierarchically porous carbon powder is then added; preferably, while the metal salt/metal precursor is under constant stirring. Typically, the solution is then heated to a temperature of about 75 °C to about 90 °C (preferably, between about 80 °C to about 85 °C) and stirred until the solvent solution evaporates leaving behind a dried powder. The dried powder may then be heated to a suitable decomposition temperature, preferably under an inert gas, such as, but not limited to, nitrogen gas. Suitable decomposition temperatures range from about 250 °C to about 400 °C; preferably, the decomposition temperature is from about 300 °C to about 350 °C. Suitable heating times range from about 4 hours to about 8 hours. In one particular embodiment, the dried hierarchically porous carbon powder doped with metal catalyst is heated at about 300 °C to about 320 °C for 6 hours, followed by an additional 2 hours of heating under nitrogen gas. In other embodiments, the hierarchically porous carbon powder is contacted with a metal salt or metal oxide under vacuum pressure. Non-limiting exemplary processes for doping hierarchically porous carbon material with metal catalysts using the incipient wetness impregnation method are provided in Example 1.

In some embodiments, the hierarchically porous carbon material may not contain nitrogen or may contain a very low nitrogen content (e.g., the hierarchically porous carbon material is assembled without using an organic amine and/or contains less than 1% nitrogen). It may therefore be desirable to add exogenous nitrogen to the hierarchically porous carbon material. As such, the hierarchically porous carbon can be doped with nitrogen in addition to or as an alternative to using an organic amine in the initial self-assembly reaction as the source of nitrogen. Suitable doping techniques are known in the art and included, for example, an incipient wetness impregnation. For instance, impregnation can be used to dope the hierarchically porous carbon material with nitrogen from a nitrogen source, such as, but not limited to polyvinyl pyrrolidone (PVP) or 4-dimethylaminopyridine (4-DMAP) at about 1% to about 20% by wt. Using such methods, the above-described process for creating the hierarchically porous carbon material is modified to perform the nitrogen doping step prior to pyrolysis. The dried porous carbon extrudates are added to a solvent solution containing the nitrogen source (e.g., PVP in DI water or 4-DMAP in acetone) and subjected to evaporation prior to pyrolysis. A summary of a non-limiting exemplary nitrogen doping process using impregnation with PVP or 4-DMAP is provided in Table 2.

Table 2: Impregnation of Nitrogen in hierarchically porous carbon extrudate.

Therefore, in some embodiments, the final hierarchically porous carbon material in monolith, pellet, chip, or powder form will be doped with both nitrogen from the organic amine in the feedstock mixture and one or more metal catalysts including, but not limited to Cu ²⁺ , Co ²⁺ , Cd ²⁺ , Ag ⁺ , Zn ²⁺ , Mg ²⁺ , Ni ²⁺ , Pt ²⁺ , Mn ²⁺ , copper oxide, zinc oxide, copper oxide/zinc oxide, or a combination thereof. The concentration of nitrogen present in the hierarchically porous carbon material is in the range from about 0.1% by wt to about 30% by wt; preferably, the concentration of nitrogen is between about 1% to about 3% by wt. The concentration of metal catalyst present in the hierarchically porous carbon material is in the range from about 0.1% by wt to about 30% by wt, e.g., 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, or 30% by wt; preferably, the concentration of metal catalyst is between about 1% by wt to about 20% by wt or about 5% by wt to about 20% by wt. Preferably, the metal catalyst is silver, copper oxide, zinc oxide, or a combination of copper oxide and zinc oxide.

This continuous process is especially amenable to automation, either specific steps or the entire process. All process steps of the method can be continuous and automated, requiring very little, if any, process interruption by operators, only requiring monitoring by means of computer or PLC panel.

Application Formulations and Filter Systems Containing Hierarchically Porous Carbon Material

As described above, the hierarchically porous carbon materials of the instant disclosure can be incorporated into filtration systems, including facemasks (e.g., N95 masks, surgical masks, cloth masks), respirators, HEPA filters, or HVAC systems. Facemasks, such as N95 masks and surgical masks typically are made from nonwoven fabric while cloth masks are made from common fabrics, such as cotton. Other masks and filter fabrics can be made from nonwoven polyester. For instance, N95 masks are made of nonwoven polypropylene fibers and are capable of trapping or capturing at least 95% of aerosol particles having a particle size of at least 0.3 microns in diameter. Air filters can be made from glass fibers, metal reinforced fiberglass, spun fiberglass, pleated paper or cloth e.g., cotton), pleated polyester, or other unwoven synthetic fibers. The ability of air filters to block small particles can be determined by their minimum efficiency reporting value (MERV) rating or other rating system commonly used in the art. For instance, an air filter with a MERV rating of 14 or higher can block or trap at least 95% of aerosol particles having a particle size of at least 0.3 microns in diameter. Regardless of the filtration ratings, the filter components in air filters, masks, and respirators do not actually kill bacteria, viruses, fungi, or other disease-causing microorganisms.

Thus, it is desired to incorporate the hierarchically porous carbon materials of the instant disclosure into the filter component of the air filter or respirator or into the fabric of the facemask to not only improve the droplet or aerosol trapping capability of the filter or mask, but to impart a biocidal function to the filter or mask. As discussed above, incorporating nitrogen in the carbon backbone of the porous carbon material potentially promotes/enhances the biocidal activity of the metal catalyst dispersed on the surface of the carbon phase. Furthermore, the increased surface area of the porous structure and distribution of the metal catalyst throughout the carbon phase increases the efficiency of the air/liquid flow through the porous carbon material thereby increasing the availability of biocidal metal for contact with the contagioncarrying aerosols, droplets, or liquid, and, therefore, the contagion-killing efficiency. For instance, an individual wearing a mask treated with the hierarchically porous carbon materials of the instant disclosure will be significantly more protected against influenza, COVID-19, and other airborne contagions because the pathogen-carrying droplets and aerosols are trapped in the carbon pores, which kills the virus itself due to the presence of the biocidal metal catalyst. Likewise, HEPA or HVAC filters treated with the hierarchically porous carbon materials of the instant disclosure will significantly decrease community spread of airborne contagion as circulating air passing through the hierarchically porous carbon-treated air filter both traps contagion-carrying aerosols and inactivates or kills the contagion itself.

The hierarchically porous carbon materials can be applied to an existing filter component using any suitable application method, such as, but not limited to, coating, rolling, or spraying application techniques. For instance, the hierarchically porous carbon materials can be formulated for coating or rolling by admixing the hierarchically porous carbon with a suitable solvent, such as water, alcohol (e.g., methanol, ethanol, propanol), acetone, or a combination thereof.

For sprayable formulations, the hierarchically porous carbon can first be ground into a fine powder as described above. About 0.1% by wt to about 2% by wt, e.g., 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, or 2%, of the hierarchically porous carbon powder is suspended in a suitable solvent including, but not limited to water, alcohol (e.g., ethanol, methanol, isopropanol), or a combination of both. In a preferred embodiment, about 0.1% by wt to about 1% by wt hierarchically porous carbon powder is admixed with a solution of water and ethanol to produce a powder suspension. In some embodiments, the solution is water. In another embodiment, the solution is absolute ethanol. A preferred solvent solution is about 1% to about 99%, e.g., 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, or 99% by volume ethanol in water; more preferably, it is about 60% by volume ethanol in water or about 80% by volume ethanol in water (e.g., a ratio of 70:30 to 80:20 ethanol to water). Conventional spray devices can be used for application, such as spray bottles, paint guns, and the like. For instance, suitable spray bottles include 14 ml / 0.47 oz Small Fine Mist Spray Bottle or loz Amber Glass Spray Bottles (Berlin Packaging, LLC, Chicago, Illinois). In other embodiments, conventional powder sprayers can be used wherein the hierarchically porous carbon powder is sprayed without the need for solvent (or with the addition of small amounts of water or other liquid to ensure adequate dispersal). For instance, a powder dust sprayer can be used for a solvent free system, such as the Harris Powder duster (PF Harris Manufacturing, Cartersville, Georgia). Large scale spray devices are also suitable for use herein, such as, but not limited to high-capacity spraying robots, rotary spraying machines, elliptical spraying machines, and spray booths.

To treat air filters (e.g., HEPA or HVAC filters), the filter material is sprayed with a mixture of hierarchically porous carbon powder suspended in a solvent solution. Likewise, fabric or cloth facemasks can be sprayed with the mixture of hierarchically porous carbon powder in the same fashion. The suspended hierarchically porous carbon powder may be applied at a concentration of about 0.1 grams to about 2 grams (e.g., 0.1 grams, 0.2 grams, 0.3 grams, 0.4 grams, 0.5 grams, 0.6 grams, 0.7 grams, 0.8 grams, 0.9 grams, 1 gram, 1.1 grams, 1.2 grams, 1.3 grams, 1.4 grams, 1.5 grams, 1.6 grams, 1.7 grams 1.8 grams, 1.9 grams, or 2 grams) of carbon per square foot filter. Preferably, the concentration is about 0.1 g to about 1 g per ft ² of filter; more preferably, the concentration is about 1 g per ft ² of filter. The electrostatic characteristics of the carbon material allows it to stick or adhere to the filter or fabric surface without any additional adhesive. As such, the air filter or facemasks exhibit biocidal characteristics in addition to enhanced droplet or aerosol capture capabilities. In one embodiment, the hierarchically porous carbon-treated fabric for a facemask is sandwiched between two antistatic fabric layers to create a three-layered arrangement where the middle fabric layer is treated with the hierarchically porous carbon powder of the instant disclosure. In this embodiment, the hierarchically porous carbon-treated fabric layer can be adhered to the inner and outer fabric layers with suitable adhesive or stitching; preferably, the hierarchically porous carbon-treated fabric surface is oriented such that the treated surface faces outward from the wearer’s mouth and nose. In another embodiment, the hierarchically porous carbon-treated fabric layer is the inner mask layer adhered or stitched to one or more outer fabric layers; preferably, with the treated surface of the hierarchically porous carbon-treated fabric layer facing outward from the wearer’s mouth and nose. In yet another embodiment, a sachet in which hierarchically porous carbon material of the instant invention is enclosed is disposed between two mask fabric layers. In this manner, filters and facemasks incorporating the material of the instant invention can be used to significantly prevent community spread of airborne diseases.

In another embodiment, hierarchically porous carbon chips or pellets are used to modify respirators or air filtration systems. For instance, the activated carbon can be replaced with the hierarchically porous carbon chips or pellets of the instant invention in the filter cartridge of a respirator to impart biocidal functionality in addition to enhanced air filtration characteristics. In yet another embodiment, hierarchically porous carbon chips or pellets can be added during manufacturing of automotive filters or other air filters to absorb smells and other contaminants and kill or otherwise inactivate airborne contagions.

Therefore, the air filter devices and systems incorporating the hierarchically porous carbon materials disclosed herein can be used to prevent or reduce circulation of airborne disease-causing microorganisms including, but not limited to bacteria (e.g., Corynebacterium diphtherias, Bordetella pertussis (whooping cough), Streptococcus pneumoniae, Neisseria meningitidis, Mycobacterium tuberculosis, Staphylococcus sp.), viruses (e.g., Varicella zoster (chicken pox), influenza viruses (such as H1N1 (Spanish flu and Swine flu), H2N2, H3N2 (Bird flu), H5N1, H7N7, H1N2, H9N2, H7N2, H7N3, H10N7, H7N9, H6N1), coronaviruses (SARS, MERS, COVID-19), Measles morbillivirus, Mumps orthorubulavirus, Hantavirus), and fungi (e.g., Pneumocystis pneumonia).

The following examples are provided to describe the invention in greater detail. They are intended to illustrate, not to limit, the invention.

Example 1: Preparation of Hierarchically Porous Carbon Materials Doped with Biocidal Metal Catalysts and Reagents Used in Examples 2-5.

Preparation of hierarchically porous carbon powder

To test the biocidal activity of the hierarchically porous carbon material, hierarchically porous carbon material containing between 1.5% and 1.9% nitrogen was produced. At room temperature, 112 g resorcinol crystals and 47.5g poloxamer F127 were added to a solvent mixture containing 337.5 g 200 proof ethanol and 337.5 g deionized (DI) water. This mixture was stirred until the solid components were fully dissolved. To this mixture, 15 g of 1,6- diaminohexane (DAH) crystals was added while stirring and allowed to dissolve. This mixture was then transferred to a reactor where 170.2 g formalin was added. The polymeric solution was then subject to curing at 76 °C for 15 hours and dried at 51 °C for 8 hours. The dried polymer was extruded and pyrolyzed to 800 °C under N2 in a furnace. The pyrolyzed carbon extrudates produced by this method had a total weight of about 70 g to about 80 g and contained about 1.5 to about 1.9 g nitrogen.

The hierarchically porous carbon material was then treated with 2 M nitric acid and then crushed through a stationary grinder. The coarse carbon particulates were transferred to a ballmill (loaded with 60 chrome plated SS balls diam 1/2”) and ground for 24 hours. After 24 hours, a fine powder (0-74 microns) was obtained. The fine powder was used for the catalyst synthesis without further treatment.

Production of hierarchically porous carbon powder doped with metal catalyst

To produce a hierarchically porous carbon powder doped with 10% zinc oxide, 2.7 g of zinc acetate was dissolved in 80 mL deionized (DI) water in a beaker. The beaker was placed on a stirring hot plate and stirred (300 rpm) until the metal salt completely dissolved in the DI water and the solution was transparent. Under constant stirring, 9 g of activated hierarchically porous carbon powder was separately weighed and added to the aqueous zinc acetate solution. To ensure sufficient mixing of the powder in the metal salt solution, the rpm of the stirring was increased as needed and then reduced to 300 rpm. The solution was heated at 80 °C by adjusting the temperature setting on the hot-plate. Stirring was continued at this temperature until the water evaporated. Stirring was reduced to 90 rpm as the water volume reduced to about 50 mL, and then continued until the carbon/catalyst powder dried completely. The dried carbon/catalyst powder was then transferred to a ceramic boat and placed in a programmable furnace at a temperature of about 320 °C with a heat ramp of about 6 h and then soaked at 320 °C for 2 hours under N2 flow.

To produce a hierarchically porous carbon powder doped with 20% zinc oxide, 5.4 g of zinc acetate was dissolved in 80 mL deionized (DI) water in a beaker. The beaker was placed on a stirring hot plate and stirred (300 rpm) until the metal salt completely dissolved in the DI water and the solution was transparent. Under constant stirring, 8 g of activated hierarchically porous carbon powder was separately weighed and added to the aqueous zinc acetate solution. To ensure sufficient mixing of the powder in the metal salt solution, the rpm of the stirring was increased as needed and then reduced to 300 rpm. The solution was heated at 80 °C by adjusting the temperature setting on the hot-plate. Stirring was continued at this temperature until the water evaporated. Stirring was reduced to 90 rpm as the water volume reduced to about 50 mL, and then continued until the carbon/catalyst powder dried completely. The dried carbon/catalyst powder was then transferred to a ceramic boat and placed in a programmable furnace at a temperature of about 320 °C with a heat ramp of about 6 h and then soaked at 320 °C for 2 hours under N2 flow.

To produce a hierarchically porous carbon powder doped with 10% copper oxide, 3.0 g of copper(II) nitrate trihydrate was dissolved in 80 mL DI water in a beaker. The beaker was placed on a stirring hot plate and stirred (300 rpm) until the metal salt completely dissolved in the DI water and the solution was transparent. Under constant stirring, 9 g of activated hierarchically porous carbon powder was separately weighed and added to the aqueous copper salt solution. To ensure sufficient mixing of the powder in the metal salt solution, the rpm of the stirring was increased as needed and then reduced to 300 rpm. The solution was heated at 80 °C by adjusting the temperature setting on the hot plate. Stirring was continued at this temperature until the water evaporated. Stirring was reduced to 90 rpm as the water volume reduced to about 50 mL, and then continued until the carbon/catalyst powder dried completely. The dried carbon/catalyst powder was then transferred to a ceramic boat and placed in a programmable furnace at a temperature of about 310 °C with a heat ramp of about 6 h and then soaked at 320 °C for 2 hours under N2 flow.

Preparation of Nutrient Agar plates

To prepare nutrient agar plates, 8 g of dehydrated Nutrient Broth (e.g., BD BACTO nutrient broth, BD Diagnostics) was added to two beakers of 500 mL deionized (DI) water. A stir bar and 15 g of dehydrated agar were added to each beaker. The beakers were moved to a hot plate and allowed to stir with heat until homogenized. Once homogenized, the volume was filled to 1 L with DI water. The contents of each beaker was poured into a 1 L screw top bottle. The bottles were autoclaved at 121°C and 15 psi for 15 minutes and cooled to 48°C ±1°C. In procedures using E. coli F _am p, 10 mL of Amp/Strep antibiotics was added to the cooled agar. Prior to pouring, the molten agar was swirled or mixed slowly on a stir plate. Then, 15-20 mL of molten nutrient agar was poured into 100 petri dishes (plates) or until no nutrient agar remained. The plates were allowed to cool undisturbed until set.

Preparation o f 2X Nutrient Agar

To prepare the 2X nutrient agar, 16 g of dehydrated Nutrient Broth (e.g., BD BACTO nutrient broth, BD Diagnostics) was first added to a beaker of 500 mL deionized (DI) water. A stir bar and 18 g of dehydrated agar was added to the beaker. The beaker was moved to a hot plate and allowed to stir with heat until homogenized. Once homogenized, the volume was filled to 1 L with DI water. The contents of the beaker was poured into a 1 L screw top bottle. The bottle was autoclaved at 121 °C and 15 psi for 15 minutes and cooled to 48°C ±1°C. Prior to pouring, the molten agar was swirled or mixed slowly on a stir plate. Then, 10 mL of molten nutrient agar was poured into 100 sterile 50 mL centrifuge tubes and put in a 45°C ±1°C water bath until use.

Preparation of 10% ZnO/C Spray Solution

First, 0.3 g of Batch 1, 2 or 3 10% ZnO/C material was added to a tared spray bottle that delivers 1.25 mL per spray. Next, 37.5 grams of DI water and 112.5 grams of absolute ethanol were added to the spray bottle. The sprayer was then screwed onto the bottle, and the bottle was vigorously shaken for a minimum of 60 seconds to create a suspension.

Preparation of 10% CuO/C Spray Solution

First, 0.3 g of 10% CuO/C material was added to a tared spray bottle that delivers 1.25 mL per spray. Next, 37.5 grams of DI water and 112.5 grams of absolute ethanol were added to the spray bottle. The sprayer was then screwed onto the bottle, and the bottle was vigorously shaken for a minimum of 60 seconds to create a suspension. Preparation of Blank Spray Solution

To a tared spray bottle that delivers 1.25 mL per spray, 37.5 grams of DI water and 112.5 grams of absolute ethanol was added. The bottle was shaken vigorously for a minimum of 60 seconds to maintain procedural consistency.

Preparation o f Textile

Textiles were cut into 12-inch x 12-inch squares. Once cut, textiles were placed each into a 4-inch, circular embroidery hoop, referred to as “sample holder”, and pulled to be taut within the sample holder. Textile samples including their respective sample holders were weighed. Weight was noted as “Unsprayed weight.” Spray Solutions were shaken for a minimum of 5 minutes to ensure suspension of any solid compounds. Textile samples were sprayed until visually coated, approximately 3-4 sprays, with either a blank spray solution, a 10% CuO/C containing spray solution, or a 10% ZnO/C Batch 1, 2, or 3 containing spray solution, as described above, to produce blank textiles and treated textiles, respectively. Each textile sample was prepared in triplicate and labeled on the sample holder. The textiles were allowed to dry in oven at 40 °C for 4hrs. The textiles and holders were weighed after drying and weights were noted as “Dry weight”. The weights of 10% ZnO/C sprayed textiles and 10% CuO/C sprayed textiles should have increased by a minimum of 0.04 grams to ensure complete coverage and a maximum amount of 0.06 grams. The spraying and drying was repeated until the desired weight range was reached. Shown in Figure 3 are photographs of a blank textile (panel A) as compared to textiles sprayed with 10% ZnO/C (panels B and C).

Preparation of Ampicillin/Streptomycin

The amp/strep solution was prepared by first dissolving 1 g of ampicillin sodium salt and 1 g streptomycin sulfate in 100 mL of DI water and filtering through a sterile 0.22-pm-pore-size membrane filter assembly. Next, 5 mL of sterile Amp/Strep was dispensed per 15 mL centrifuge tube. The tubes were dated and stored frozen at 20°C. A vial was thawed at room temperature or rapidly in a 36°C ± 1.0°C water bath and mixed well prior to use. Preparation of Phosphate Buffered Saline (PBS)(1 L)

The PBS was prepared by first adding 8 g sodium chloride, 0.2 g potassium chloride, 1.42 g sodium phosphate, and 0.24 potassium phosphate to 800 mL of DI water in a 1 L beaker with a stir bar. The beaker was placed on a stir plate and allowed to stir until homogenized. The volume was then adjusted to 1 L with DI water. The unsterile PBS was then poured into a 1 L screw top bottle and autoclaved at 121°C and 15 psi for 15 minutes. The PBS was allowed to cool to room temperature before use.

Preparation of Bacteria Cultures

All cultures were prepared as follows. The organism selected for each set of cultures was selected based on the set of tests that were being prepared at the time. The procedure for each of E. coli F _amp . ". pneumoniae, and S. aureus followed the same culture preparation steps and only differed in the use of antibiotics in E. coli F _am p and the growth time in S. aureus (changed from 18-20 hours to 24-36 hours).

From frozen bacterial stock, 1 mL of bacteria stock was thawed in a 37°C ±1°C incubator for 1 minute. The frozen stock was added to 25 mL of TSB and incubated at 37°C ±1°C while shaking overnight. 25 mL of sterile TSB was dispensed into a 125-mL shaker flask. The flask was inoculated with 250 pL of overnight bacteria culture. If preparing a E. coli F _am p culture, 250 pL of Amp/Strep lOOx stock antibiotics prepared as above was added. The flask was incubated at 37°C ±1°C and was shaken at 100 to 150 rpm overnight (18 to 20 hours or 24-36 for S. aureus).

Preparation of Bacteriophage Cultures- MS2 and T4

An overnight bacteria stock culture of either E. coli F _amp or E. coli B was prepared for Coliphage MS2 or T4, respectively, as described above. Between 18-20 hours post inoculation, 50 pL of stock MS2 or T4 was added to the culture, and the infection time was noted. Next, 4 cultures per experiment were infected to ensure the phage did not inactivate itself when left without a host for extended periods of time. At 24 hours post bacteriophage infection, the cultures were put in 50 mL centrifuge tubes. The culture was centrifuged at 3,500 rpm for 30 minutes to pellet cellular debris. The supernatant was removed and saved in new sterile 50 mL centrifuge tubes and stored at 4 °C until ready to use.

Example 2: Anti-Bacterial Activity of Hierarchically Porous Carbon Material (K. pneumoniae and A aureus).

To test the biocidal activity of hierarchically porous carbon material with metal catalyst on bacteria, 3 batches of 10% ZnO/C were prepared as described in Example 1 and used to determine the needed exposure time to kill two separate bacteria species, K. pneumoniae and S. aureus. These bacteria were selected due to the United States Environmental Production Agency’s “Product Performance Test Guidelines OCSPP 810.2500: Air Sanitizers Efficacy Data Recommendations”. The procedure followed the same steps for both bacterium and only differed in the growth time in S. aureus.

First, 85 agar plates were prepared as above and labeled. In addition, 500 mL of sterile PBS was prepared as above, and 0.9 mL was aliquoted into 85 pre-sterilized, prelabeled, 1.2 mL Eppendorf tubes. A Bunsen burner was set up and ignited. Absolute ethanol was added to a shallow dish to be used to sterilize the metal cell spreader between each plate. Next, 9.990 mL of PBS was added to a 50 mL centrifuge tube, and 10 pL of the desired culture prepared above was added to the 9.990 mL of PBS to create a 1/1000 diluted culture. To four 15 mL centrifuge tubes, 2 mL of the diluted culture was added. The tubes were labeled as control, ZnO/C Batch 1, ZnO/C Batch 2, and ZnO/C Batch 3. Then, 55 mg of pre-sterilized ZnO/C was added to the respective tube. The amount of ZnO/C that was added per batch for each set in the K. pneumoniae test is summarized in Table 3 A, while the amount of ZnO/C that was added per batch for each set in the S. aureus test is summarized in Table 4A. A timer was started and immediately 0.5 mL was removed from each tube and put in Eppendorf tubes labeled with the respective batch label and 0 mins.

Dilutions and plating began while the 2-hour timepoint was still running. The 0 min. timepoints were serially diluted 10-fold by adding 0.1 mL of the stock to the corresponding prelabeled 1.2 mL Eppendorf tube containing 0.9 mL of sterile PBS to create Dilution 1. 0.1 mL of Dilution 1 was added to 0.9 mL of sterile PBS to create Dilution 2. This was repeated until there were 7, 10-fold dilutions. 0.1 mL was removed from Dilution 7 and discarded so all tubes would now contain 0.9 mL per dilution. 0.1 mL of each dilution was pipetted onto its corresponding, pre-labeled agar plate and spread using a metal cell spreader by turning the plate under the cell spreader until fully and evenly coated. The cell spreader was sterilized between each by submerging the cell spreader in the prepared dish of ethanol and flaming it using the Bunsen burner. The dilution and plating steps were repeated with ZnO/C Batch 1, ZnO/C Batch 2, and ZnO/C Batch 3 at 0 minutes. Next, 0.5 mL was removed from each tube at 10 minutes and 2 hours and placed in their respective label plus the timepoint. The dilution and plating steps were repeated for the remaining timepoints for the controls and the ZnO/C treated tubes. The plates were allowed to dry after plating before inverting and placing in a 37°C ±1°C incubator for 24 hours for K. pneumoniae and 24-36 hours for S. aureus. The colonies were counted and used to calculate the bacterial titers for the untreated and treated plates at different exposure times. Table 3B-D shows the bacterial titers of K. pneumoniae recovered for the treated versus untreated at each time point. Table 3B, 3C, and 3D show the first, second and third set of K. pneumoniae respectively. Table 4B-D shows the bacterial titers of S. aureus recovered for the treated versus untreated at each time point. Table 4B, 4C, and 4D show the first, second and third set of S. aureus respectively. In each set, treatment of the bacteria with 10% ZnZO/C resulted in a significant reduction in colony forming units (CFUs) as compared to controls, resulting in nearly 100% reduction by 120 minutes.

Shown in Figure 4 are plates showing bacterial colony growth for untreated S. aureus (Panel A) as compared to S. aureus treated with 10% ZnO/C for 120 minutes (panels B-D). The serial dilutions are left to right and top to bottom from Dilution 1 to Dilution 7. Many fewer colonies can be seen in the S. aureus treated as compared to the untreated plates at all dilutions.

Table 3. K. pneumoniae treated with hierarchically porous carbon material.

A.

B. c.

D.

Table 4. S. aureus treated with hierarchically porous carbon material.

A.

B.

C.

D.

Example 3: Anti-Bacterial Activity of Hierarchically Porous Carbon Material (E. coli).

To test the biocidal activity of hierarchically porous carbon material with metal catalyst on bacteria, 2 batches of 10% ZnO/C were prepared as described above and used to determine the needed exposure time to kill E. coli Famp. Escherichia coli F _am p was selected as the test bacteria due to its previous use in the full Environmental Production Agency study titled, “Efficacy of 10% Zinc Oxide on Carbon against Airborne Bacteria” and due to its antibiotic resistance to decrease likelihood of culture contamination.

First, 63 agar plates were prepared as described above with the addition of Amp/Strep antibiotics and labeled. Also, 500 mL of sterile PBS was prepared as described above, and 0.9 mL was aliquoted into 85 pre-sterilized, prelabeled, 1.2 mL Eppendorf tubes. A Bunsen burner was set up and ignited. Absolute ethanol was added to a shallow dish to be used to sterilize the metal cell spreader between each plate. Next, 19 mL of PBS was added to a 50 mL centrifuge tube, and 1 mL of the overnight E. coli F _amp culture prepared above was added to the 19 mL of PBS to create a 1/20 diluted culture. To four 15 mL centrifuge tubes, 2 mL of the diluted culture was added. The tubes were labeled as control, ZnO/C Batch 1 and ZnO/C Batch 2. Then, 55 mg of pre-sterilized ZnO/C was added to the respective tubes. A timer was started and immediately 0.5 mL was removed from each tube and put in Eppendorf tubes labeled with the respective batch label and 0 mins.

Dilutions and plating began while the 2-hour timepoint was still running. The 0 min timepoints were serially diluted 10-fold by adding 0.1 mL of the stock to the corresponding prelabeled 1.2 mL Eppendorf tube containing 0.9 mL of sterile PBS to create Dilution 1. Next, 0.1 mL of Dilution 1 was added to 0.9 mL of sterile PBS to create Dilution 2. This was repeated until there were 7, 10-fold dilutions. Then, 0.1 mL was removed from Dilution 7 and discarded so all tubes would now contain 0.9 mL per dilution. Next, 0.1 mL of each dilution was pipetted onto its corresponding, pre-labeled agar plate and spread using a metal cell spreader by turning the plate under the cell spreader until fully and evenly coated. The cell spreader was sterilized between each by submerging the cell spreader in the prepared dish of ethanol and flaming it using the Bunsen burner. The dilution and plating steps were repeated with ZnO/C Batch 1 and ZnO/C Batch 2 at 0 minutes. Next, 0.5 mL was removed from each tube at 10 minutes and 2 hours and placed in their respective label plus the timepoint. The dilution and plating steps were repeated for the remaining timepoints for the controls and the ZnO/C treated tubes. The plates were allowed to dry after plating before inverting and placing in a 37°C ±1°C incubator for 24 hours. The colonies were counted and used to calculate the bacterial titers for the untreated and treated plates at different exposure times.

Shown in Figure 5 are plates showing bacterial colony growth for untreated E. coll F,-,m _P (Panel A) as compared to E. coll F _am p treated with 10% ZnO/C for 120 minutes (panels B-D). The serial dilutions are left to right and top to bottom from Dilution 1 to Dilution 7. No colonies can be seen in the E. coll F _amp treated as compared to the untreated plates.

Example 4: Anti-Viral Activity of Hierarchically Porous Carbon Material (Anti-Viral Efficacy).

To test the anti-viral activity of hierarchically porous carbon material with metal catalyst, 10% ZnO/C powder was prepared as described above and used to test the viability of Coliphage MS2, which is known to replicate in and destroy E. coll F _amp bacterial cells. Textiles were prepared as described above with 10% ZnO/C Batch 1, 10% ZnO/C Batch 2, and 10% ZnO/C Batch 3. In addition, 1 L of 2X Nutrient agar was prepared as stated previously and cooled to 42°C ±1°C. Then, 10 mL of 2X Nutrient agar was aliquoted into 95 pre-sterilized, 50 mL centrifuge tubes and placed in a 42°C ±1°C water bath. To 2 L of sterilized PBS, 10 mL of 4M magnesium chloride was added to make a sterile magnesium chloride solution. Next, 9.9 mL of the sterile PBS-MgCl solution was aliquoted into 95 pre-sterilized 15 mL centrifuge tubes. The tubes were labeled tubes as Blank a-c, 1-7, Batch la-c, 1-7, Batch 2a-c, 1-7, Batch 3a-c, 1-7 and Control, 1-7. Also, 10 mL of PBS solution was added to a separate tube to serve as a temperature control tube.

A PARI Vios PRO Nebulizer System with LC Plus was set up in properly ventilated biosafety cabinet and was clamped in place. A 12-inch length piece of 3/4-inch inner diameter, clear, Tygon PVC tubing was affixed to the outlet of the nebulizer. With a laboratory clamp, the resting height of the outlet tubing was adjusted until it was exactly 1/4 inch above a textile sample with a petri dish beneath it. To sterilize the nebulizer, 1.5 mL of absolute ethanol was added to the nebulizer solution cup and allowed to run until the nebulizer cup was completely empty. To ensure no ethanol remained in the nebulizer cup, the nebulizer was left to dry for 20 minutes before proceeding. 10 mL of sterile PBS-MgCl solution was added to 13 petri dishes and labeled as (3) Blank a-c, (3) ZnO/C Batch la-c treated, (3) ZnO/C Batch 2a-c treated, (3) ZnO/C Batch 3a-c treated, and Control. Each petri dish was covered with the corresponding textile sample, leaving the control without a textile sample. Then, 4 mL of MS2 stock phage was added to the nebulizer for each test plate and was allowed to run until the nebulizer was empty. This was repeated until all were completed.

The infected PBS-MgCl solution test sample was removed from each petri dish and stored in a 15 mL centrifuge tube with their respective labels plus the word “stock”. Each stock was serially diluted 10-fold by adding 1.1 mL of stock to the corresponding prelabeled 15 mL tube previously prepared containing 9.9 mL of sterile PBS-MgCl to create serial dilution 1. Next, 1.1 mL of dilution 1 was added it to 9.9 mL of sterile PBS-MgCl to create serial dilution 2. This was repeated using dilution 2 to create dilution 3 and repeated until a total of 7, 10-fold dilutions were made. Then, 1.1 mL was removed from dilution 7 and discarded so the volume of all tubes was equal to 9.9 mL. The dilutions were placed in a 36°C ±1°C water bath until the temperature flask reached equilibrium with the water temperature. Next, 1 mL of E. coll Famp overnight culture, as prepared in Example 1, was added to each dilution tube, and was placed in a 42°C ±1°C water bath for a minimum of 3 minutes and a maximum of 10 minutes.

Each tube was mixed with a 10 mL aliquot of 2X Nutrient agar previously prepared and transferred to prelabeled petri dish. The dilution and plating steps were repeated until all test plates were mixed with the prepared 2X Nutrient agar and allowed to set. The control samples were run by nebulizing MS2 directly onto the petri plate with sterile PBS-MgCl solution without any test material to ensure viability of virus was maintained throughout the experiment. The control dilutions were performed to determine viral titer. The solidified petri dishes were placed inverted into a 37°C ±1°C incubator for 24 hours. After 24 hours, the plaques were counted, and the virus titer was determined for each set. The mean plaque forming unit (PFU)/replicate was calculated 2.35xl0 ⁹ from the untreated textiles as compared to only 1.96 xlO ⁵ PFU/replicate from the textiles treated with 10% ZnO/C. Figure 6 shows the PFUs on dilution 5, 6, and 7 plates for the untreated group (Panel A) as compared to the 10% ZnO/C-treated group (Panel B)

Example 5: Anti-Viral Activity of Hierarchically Porous Carbon Material.

To test the anti-viral activity of hierarchically porous carbon material (1.5 to 1.9% N) doped with metal catalyst, 10% ZnO/C and 10 % CuO/C powder were prepared as described in Example 1 and used to test the viability of Coliphage T4, which is known to replicate in and destroy E. coll bacterial cells. Suspensions of 10% ZnO/C, 10% CuO/C, and carbon only were prepared as described above. Textiles were sprayed as described in Example 1 with 10% ZnO/C, 10% CuO/C, and carbon only solutions. One textile was left untreated to serve as a control.

Five Nutrient Agar plates were prepared as described in Example 1. E. coll B samples were diluted 1/10 by first aliquoting 900 pL sterile water into 5 sterile Eppendorf tubes and then adding 100 pL of the E. coll B cell culture (Carolina Biological Supply Company, Burlington, NC). Each of the five agar plates was aliquoted with 1 mL of the 1/10 E. coll B dilution and tilted until the E. coll B culture coated the total area of the plate (surface area of plate = 58 cm ² ). One plate was used as a reference plate, and each textile and hoop sample was placed on the remaining four plates. Next, Coliphage T4 (500 pL) was nebulized through the textiles onto plates grown with E. coll B using PARI Vios Pro Nebulizer system with LC. For the reference plate, Coliphage T4 (500 pL) was nebulized directly onto the plate. Then, 0.75% Nutrient agar at 42 °C was poured on top of each plate and allowed to solidify. Each of the plates were covered and left in the incubator at 37 °C for 24 hours.

Figure 7 shows the plates from each of the reference, textile only, textile with carbon only, textile with 10% ZnO/C, and textile with 10% CuO/C samples. The reference plate showed minimum E. coll growth on the agar surface indicating active Coliphage T4 (Figure 7A). In comparison, the plates from the textiles sprayed with 10% ZnO/C and 10% CuO/C exhibited comparatively greater E. coll growth than the reference plate (Figures 7D and 7E). The plate from the textile only (no carbon or metal catalyst) sample exhibited E. coll growth comparable of that to the reference plate (see Figure 7B). The plate from the textile with carbon only (no metal catalyst) sample exhibited approximately half of the E. coll growth as the 10% ZnO/C and 10% CuO/C samples (see Figure 7C).