Materials and methods for removing atmospheric carbon

Abstract

The subject invention relates to systems and their use in filtering air while simultaneously capturing carbon dioxide from the air. More specifically, the subject invention provides a filter comprising an air-permeable substrate and a component that converts atmospheric CO2 into a non-corrosive salt. The filter can be used passively in closed environments having access to air flow, as well as actively in air purifiers, HVAC systems and vacuums. Advantageously, the subject invention can be utilized by individuals in their homes and businesses as a way to contribute to reducing the negative impacts of climate change.

Description

[0001] DESCRIPTION

[0002] MATERIALS AND METHODS FOR REMOVING ATMOSPHERIC CARBON

[0003] CROSS-REFERENCE TO RELATED APPLICATION

[0004] This application claims priority to U.S. Provisional Application No. 63 / 725,234, filed November 26, 2024, which is incorporated herein by reference in its entirety.

[0005] BACKGROUND OF THE INVENTION

[0006] Environmental contaminants can adversely affect the health of humans and animals who inhale the contaminated air. For example, contaminants such as airborne viruses, bacteria, molds, and other microorganisms, as well as chemical pollutants such as volatile organic compounds (VOC), can cause eye, nose, and throat irritation, headache, fatigue, dizziness, breathing difficulties, asthma attacks, pathogen-related disease, and other symptoms and long-term effects, such as cancer. The effects caused by inhalation of contaminated air can be particularly harmful in enclosed indoor spaces.

[0007] Therefore, providing a means for decontaminating or purifying indoor air in buildings (for example, commercial, residential, and industrial buildings) is important to improve indoor air quality. Many air purification devices for removal of pollutants from indoor air have been used, such as central heating, ventilating, and air-conditioning (HVAC) filters, high- efficiency particular air (HEP A) filters, photo-electrochemical oxidation (PECO) filters, ultraviolet (UV) light, ionization systems, and others. However, traditional filters such as HVAC and HEPA filters do not mitigate increased levels of CO2 in indoor air, which has been shown to increase discomfort and fatigue, increase respiratory issues, reduce sleep quality, decrease productivity and reduce cognitive function.

[0008] Carbon dioxide is a “greenhouse gas,” or “GHG,” which enters the atmosphere through burning fossil fuels (coal, natural gas, and oil), solid waste, trees and wood products, and also as a result of certain chemical reactions, e.g., the manufacture of cement. Especially since the Industrial Revolution began in the 1700s, human activity has contributed to the amount of greenhouse gases in the atmosphere by burning fossil fuels, cutting down forests, and conducting other industrial activities. Many greenhouse gases emitted into the atmosphere remain there for long periods of time ranging from a decade to many millennia. Over time these gases are removed from the atmosphere by chemical reactions or by emissions sinks, such as the oceans and vegetation that absorb greenhouse gases from the atmosphere. World leaders have atempted to curb the increase of GHG emissions through treaties and other inter-state agreements. One such atempt is through the use of carbon credit systems. A carbon credit is a generic term for a tradable certificate or permit representing the right to emit one ton of carbon dioxide, or an equivalent GHG. In a typical carbon credit system, a governing body sets quotas on the amount of GHG emissions an operator can produce. Exceeding these quotas requires the operator to purchase extra allowances from other operators who have not used all of their carbon credits.

[0009] One goal of carbon credit systems is to encourage companies to invest in more green technology, machinery and practices in order to benefit from the trade of these credits. Under the Kyoto Protocol of the United Nations Framework Convention On Climate Change (UNFCCC), a large number of countries have agreed to be bound internationally by policies for GHG reduction, including through trade of emissions credits. While the United States is not bound by the Kyoto Protocol, and while there is no central national emissions trading system in the U.S., some states, such as California and a group of northeastern states, have begun to adopt such trading schemes.

[0010] Most people around the world are aware and concerned with the growing threat of climate change, primarily driven by the increase in CO2 levels in the atmosphere. Every human being on the planet contributes to the CO2 increase. This can be determined in terms of a “personal carbon footprint.” For most people, the options around reducing their footprint have to do with making changes to their lifestyle choices, choosing more sustainable options, and more recently, buying carbon credits from the voluntary carbon markets. People are increasingly looking for sustainable alternatives in their buying choices. Many of these choices however, are expensive or inconvenient, thus limiting widespread adoption. And finally, all these options relate to emissions avoidance, i.e., they focus on reducing their carbon footprint by choosing less carbon intensive options. Almost none of the choices currently available to the average individual deal with active CO2 removal from the atmosphere.

[0011] To put this in perspective, increasing emissions avoidance aim to reduce further increases in atmospheric CO2 levels; however, to ultimately reduce the amount of CO2 in the atmosphere in short to medium term timelines, atmospheric CO2 removal is required. The later (atmospheric CO2 removal through Carbon Capture Utilization and Storage, and Direct Air Capture) has largely been the domain of large industrial conglomerates or government funded initiatives because of the infancy in available technologies, as well as the associated expenses involved. Therefore, there is a need for technologies that everyday consumers can implement in their daily lives to contribute to the global efforts for atmospheric CO2 removal.

[0012] BRIEF SUMMARY OF THE INVENTION The subject invention provides cost-effective devices and methods for removing CO2 from air with overall carbon neutral or carbon negative effects.

[0013] In one embodiment, the subject invention provides air filtration systems that capture atmospheric carbon dioxide (CO2) in addition to providing a level of air quality suitable for use in enclosed environments, including, but not limited to, homes, residential buildings, commercial buildings, hotels, cars, buses, trains, airplanes, cruise ships, educational facilities, offices, and government buildings.

[0014] In certain embodiments, the subject invention provides a filter that captures and mineralizes indoor CO2. The filter can be utilized on its own as a standalone carbon-capture filter or it can be integrated into, for example, a high-efficiency particular air (HEP A) filter or an ultralow particulate air (ULPA) filter such that it can also function as a filter for collecting particles of air impurities such as, for example, particulate matter and smoke, pollen, mold, dust, airborne pathogens (including viruses such as COVID and the common cold), pet fur and dander, and volatile organic compounds (VOC). Unlike other air purification systems in the art, which seek to simply avoid further CO2 emissions, the present device actively removes CO2 from the atmosphere with a carbon neutral or carbon negative method.

[0015] The CO2-absorbing agent can be for example calcium hydroxide or magnesium hydroxide, in the form of, for example, pellets or rocks. The receptacle can include a sensor that determines, and preferably provides a notification, when the contents of the receptacle need to be replaced.

[0016] In a specific embodiment, the device comprises a housing having a first end comprising an inlet for receiving air, and second end opposite the first end, wherein the second end comprises an outlet for exhausting air. The housing provides an air flow path for the flow of air into the inlet and out of the outlet. In some embodiments, the device utilizes a blower and / or an air induction fan to draw air into the inlet.

[0017] Within the housing, the device preferably comprises at least one filter positioned within the housing between the first end and the second end such that the air flow path passes through the at least one filter. Preferably, the at least one filter is a carbon-capture filter according to the subject invention.

[0018] In preferred embodiments, the combination carbon-capture and air filtration system is powered using renewable energy, such as solar energy or geothermal energy, thereby reducing the overall carbon footprint of operating the system.

[0019] Advantageously, in certain embodiments, the subject invention can be utilized by individuals in their homes and businesses as an everyday source of air filtration and as a way to contribute towards efforts of reducing atmospheric greenhouse gases through Direct Air Capture (DAC). Furthermore, the subject invention can be adapted for use in a multitude of home appliances, and given the sheer global volume of said appliances, use of the described device and methods can contribute to a meaningful difference in the fight against climate change.

[0020] The technology of the subject invention can also be utilized for CO2 removal from mid to large scale CO2 emitters, such as biogas plants and ships.

[0021] Biogas plants use biomass from, for example, manure, agricultural waste, wastewater and trash to make biogas, which is typically a combination of methane, CO2 and H2S.

[0022] The biogas that is produced in such plants is often burned to produce electricity; however, because of increasing concerns of CO2 emissions, it is advantageous to capture and dispose of the CO2 that is produced by biogas plants. Current methodologies for such capture and disposal typically involve capturing CO2, which is then put in water and either used as input stock for industrial use (e.g., carbonation of drinks or conversion to plastics), or shipped to a permanent underground storage location.

[0023] This is not an efficient process because of the expense, and carbon utilization, associated with shipping the CO2 to a distant storage facility and pumping it into a location with the hope that it will remain there.

[0024] In accordance with the subject invention, an end product that is valuable in, for example, pharmaceuticals, food, agriculture and / or construction is created. Further, in preferred embodiments, the carbon capture system is carbon negative (by, for example, utilizing a waste source and also green energy), which makes it very beneficial to the environment.

[0025] In one embodiment, biogas (preferably after going through an H2S scrubber to remove H2S that would otherwise react with Ca(OH)2 and Mg(0H)2) is sent in a forced stream through the CCh-absorbing agent of the subject invention, which rapidly absorbs the CO2 and turns it into its carbonate forms.

[0026] The remaining stream is purified methane, which, in one embodiment, can be piped to collection points and then processed later to turn it into green hydrogen to, for example, be used in the manufacture of plastics or combusted to make electricity.

[0027] A further embodiment of the subject invention involves the shipping industry where CO2 can be removed from the exhaust of a water-borne vessel. Shipping is a hard-to-abate industry sector; every opportunity to reduce the carbon footprint in the shipping industry is beneficial.

[0028] Large water-borne vessels, such as cruise ships, ferries, cargo ships / freighters and naval ships, typically have a desalination plant, which provides an onboard source of brine. Using, for example, green energy from onboard sources (e.g., Magnus turbines, solar, or wave action), the CC>2-removing material can be created from brine, it can then be inserted into the ship’s exhaust stream. The carbonate precipitate created by the removal of CO2 from the exhaust stream can then be commercially used, or preferably, put into the ocean to combat ocean acidification.

[0029] Advantageously, the net result of the carbon capture and storage methods of the subject invention is carbon neutral or, preferably, carbon negative. Importantly, the C Ch-absorbing material can be produced using a carbon negative process.

[0030] There are existing technologies that use both calcium and magnesium hydroxide to capture CO2; however, with these existing technologies the CaOI and MgOI are typically produced in a highly carbon intensive manner. Because of that carbon intensive process, the CO2 absorbers are used for CO2 absorption in a closed loop “capture” system, i.e., after the CO2 is captured and turned into carbonate, the carbonate is heated and the CO2 is released back into water where it is stored to be transported to an industrial plant for its industrial utilization, or to underground storage. When the CO2 is released from the heating, the material becomes its oxide / hydroxide form again and is used again in the same process (but never put to external commercial use). This is in direct contrast to the methods of the subject invention, which are carbon negative and produce commercially valuable materials.

[0031] Advantageously, the subject invention can be fashioned completely with green (and / or sustainable) materials, resulting in a low-carbon footprint associated with producing and using the invention. In preferred embodiments, the entire process of producing and using the invention results in a net removal effect on atmospheric CO2.

[0032] BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 depicts a schematic of airflow (from left to right) through an air purifier device according to an embodiment of the subject invention.

[0034] Figure 2 shows the air filter receptacle system.

[0035] Figure 3 shows the localized carbon capture and storage system of the subject invention as applied to a biogas plant.

[0036] Figure 4 shows a cost-efficient and self-sufficient carbon capture system for ships.

[0037] DETAILED DESCRIPTION OF THE INVENTION

[0038] The subject invention provides devices and methods for removing CO2 from air using carbon-negative systems and methods.

[0039] More specifically, in one embodiment, the subject invention provides air filtration systems capable of capturing atmospheric carbon dioxide (CO2) in addition to providing a level of air quality suitable for use in any substantially enclosed environment, including, but not limited to, homes, residential buildings, commercial buildings, hotels, cars, buses, trains, airplanes, educational facilities, offices, and government buildings.

[0040] The technology of the subject invention can also be utilized for efficient and environmentally-friendly removal of CO2 from mid or large scale CO2 emitters, such as biogas plants and ships.

[0041] There are existing technologies that use both calcium and magnesium hydroxide to capture CO2; however, with these existing technologies the CaOlT and MgOtT are typically produced in a highly carbon intensive manner. Because of that carbon intensive process, the CO2 absorbed are used for CO2 absorption in a closed loop “capture” system, i.e., after the CO2 is captured and turned into carbonate, the carbonate is heated and the CO2 is released back into water where it is stored to be transported to an industrial plant for its industrial utilization, or to underground storage. When the CO2 is released from the heating, the material returns to its oxide / hydroxide form again, and is used again in the same process (but never put to external commercial use). This is in direct contrast to the methods of the subject invention, which are carbon negative and create valuable products.

[0042] Advantageously, the subject invention can be practiced in large part, or completely, with green (and / or sustainable) materials, resulting in a low-carbon footprint associated with practicing the invention. In certain embodiments, the entire process of producing and using the invention results in a net removal effect on atmospheric CO2.

[0043] Very few options exist currently to permanently store CO2 at scale other than geological storage, which is very expensive for small and medium scale emitters.

[0044] Advantageously, the subject invention provides a localized capture and storage solution that utilizes waste streams to create a CO2 removal system that is cost effective, carbon negative, and rapidly scalable. By being localized, lengthy and carbon intensive shipments of captured CO2 are avoided. In addition to this technology qualifying for both ETS and Voluntary Market carbon credits, the output is a valuable product for other industries.

[0045] The methods and systems of the subject invention are fundamentally different from conventional carbon capture and utilization systems, especially alkaline-based ones, because they utilize green energy to make the alkaline absorbents from a waste source (e.g., desalination water brine or salt production waste water brine). Thus, the captured / precipitated CO2 in the form of carbonate is carbon negative and does not need to be then transformed into another medium for transport and ultimate storage. The resulting carbonates also have commercial value.

[0046] Preferred CO2 absorbents are Ca(OH)2 and / or Mg(0H)2 because they capture higher amounts of CO2, and are valuable in their carbonate form as, for example, a soil amendment in farming, as a nutritional supplement for livestock, and as a key ingredient in construction. They are also safer and non-toxic.

[0047] More specifically, calcium and magnesium carbonates are used in soil to neutralize acidity and supply essential nutrients to plants. They are also essential supplements for livestock for building healthy bodies, muscle and tissue growth.

[0048] Further, calcium provides structural support for cell walls, regulates enzyme activity, and acts as a messenger to trigger responses to stress and development. It is essential for bone growth, promoting cell division, and improving the uptake and translocation of other nutrients.

[0049] Magnesium is a core component of chlorophyll, which is vital for photosynthesis. It also activates enzymes, aids in energy transfer, transports carbohydrates, and helps maintain structural integrity in cell components like membranes and ribosomes.

[0050] Construction projects rely heavily on calcium carbonate, where it is the primary ingredient in the manufacture of cement. It is an essential mineral component for the production of plaster, mortar and concrete. It is also used in flue gas desulfurization and water treatment, and as fdler and pigment in products such as plastics, paints, and paper, and serves as a supplement and antacid in pharmaceuticals and healthcare.

[0051] Additionally, magnesium carbonate is used to produce lightweight building materials such as wall panels and fireproof boards. Due to its heat resistance and fire resistance, magnesium carbonate has become an efficient component of building materials, providing better structural safety and durability.

[0052] Magnesium carbonate is also widely used in other industries, such as rubber, chemical industry, food, and paper-making.

[0053] Further, the alkaline products of the methods of the subject invention can be used to combat ocean acidification. The ocean is naturally alkaline, with a pH measurement of 8.15 in 1950 that has now reduced to 8.05 in 2020, which is a 30% increase in acidity. This is from absorbing the excess anthropogenic CO2 generated by human activity (oceans have been absorbing about 30% of the emitted CO2). This acidification seriously impacts marine life, which have follow-on impacts on the global ecosystem in general. Acidification makes it harder for organisms such as oysters, clams, corals, and pteropods to build and maintain their calcium carbonate structures. Many keystone fish species are affected in their ability to detect predators, making them vulnerable. The growth of new coral reefs is slowed, and existing reefs are weakened, eroded, and start to die - seriously impacting marine diversity. Coral reefs account for 25% of all marine life. Thus, the precipitated carbonate can be used for many economically and / or environmentally useful purposes including farming, the livestock industry, health applications, and construction and other industries, as well as reducing the alkalinity of oceans.

[0054] Selected Definitions

[0055] As used herein, a HEPA filter is a “high efficiency particulate air” filter capable of removing at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles. HEPA filters have a most penetrating particle size (MPPS) of 0.3 pm (meaning particles that are larger or smaller can also be trapped).

[0056] As used herein, a ULPA filter is an “ultra-low particulate air” filter capable of removing at least 99.999% of dust, pollen, mold, bacteria, and any airborne particles with a MPPS of 0.12 pm.

[0057] As used herein, “MERVs” stands for Minimum Efficiency Reporting values, which report a filter’s ability to capture larger particles between 0.3 and 10 pm. Higher MERV ratings indicate better trapping of smaller-sized particles.

[0058] As used herein, a “green” compound or material means at least 95% derived from natural, biological and / or renewable sources, such as plants, animals, minerals and / or microorganisms, and furthermore, the compound or material is at least partially biodegradable. Additionally, in some embodiments, “green” compounds or materials are minimally toxic to humans and can have a LD50>5000 mg / kg.

[0059] As used herein, “enhancing” means improving or increasing.

[0060] As used herein “preventing” or “prevention” of a situation or occurrence means delaying, inhibiting, suppressing, forestalling, and / or minimizing the onset, extensiveness or progression of the situation or occurrence. Prevention can include, but does not require, indefinite, absolute or complete prevention, meaning it may still develop at a later time. Prevention can include reducing the severity of the onset of such a situation or occurrence, and / or stalling its development to a more severe or extensive situation or occurrence.

[0061] Ranges provided herein are understood to be shorthand for all of the values within the range. For example, a range of 1 to 20 is understood to include any number, combination of numbers, or sub-range from the group consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, as well as all intervening decimal values between the aforementioned integers such as, for example, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, and 1.9. With respect to sub-ranges, “nested sub-ranges” that extend from either end point of the range are specifically contemplated. For example, a nested sub-range of an exemplary range of 1 to 50 may comprise 1 to 10, 1 to 20, 1 to 30, and 1 to 40 in one direction, or 50 to 40, 50 to 30, 50 to 20, and 50 to 10 in the other direction.

[0062] As used herein, “reduction” refers to a negative alteration, and the term “increase” refers to a positive alteration, wherein the negative or positive alteration is at least 0.25%, 0.5%, 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 70%, 75%, 80%, 85%, 90%, 95%, or 100%.

[0063] As used herein, “reference” refers to a standard or control condition.

[0064] The transitional term “comprising,” which is synonymous with “including,” or “containing,” is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. By contrast, the transitional phrase “consisting of’ excludes any element, step, or ingredient not specified in the claim. The transitional phrase “consisting essentially of’ limits the scope of a claim to the specified materials or steps “and those that do not materially affect the basic and novel characteristic(s)” of the claimed invention. Use of the term “comprising” contemplates other embodiments that “consist” or “consist essentially” of the recited component(s).

[0065] Unless specifically stated or clear from context, as used herein, the term “or” is understood to be inclusive. Unless specifically stated or obvious from context, as used herein, the terms “a,” “and” and “the” are understood to be singular or plural.

[0066] Unless specifically stated or obvious from context, as used herein, the term “about” is understood as within a range of normal tolerance in the art, for example within 2 standard deviations of the mean. About can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value.

[0067] The recitation of a listing of chemical groups in any definition of a variable herein includes definitions of that variable as any single group or combination of listed groups. The recitation of an embodiment for a variable or aspect herein includes that embodiment as any single embodiment or in combination with any other embodiments or portions thereof. All references cited herein are hereby incorporated by reference in their entirety.

[0068] Reducing Carbon Footprint

[0069] A “carbon footprint” is a measure of the total amount of carbon dioxide (CO2) and other GHGs emitted directly or indirectly by a human activity or accumulated over the full life cycle of a product or service. As just one example, a product that requires transportation over many miles by truck may have a larger carbon footprint than an alternative product that does not require longdistance transportation. Carbon footprints can be calculated using a Life Cycle Assessment (LCA) method, or can be restricted to the immediately attributable emissions from energy use of fossil fuels. A life cycle assessment (LCA, also known as life cycle analysis, ecobalance, and cradle-to-grave analysis) is the investigation and valuation of the environmental impacts of a given product or service caused or necessitated by its existence. The life cycle concept of the carbon footprint means that it is all- encompassing and includes all possible causes that give rise to carbon emissions. In other words, all direct (on-site, internal) and indirect emissions (off-site, external, embodied, upstream, downstream) need to be taken into account.

[0070] Normally, a carbon footprint is expressed as a CO2 equivalent. Carbon dioxide equivalency is a quantity that describes, for a given mixture and amount of GHG, the amount of CO2 that would have the same global warming potential (GWP), when measured over a specified timescale (generally, 100 years). Carbon dioxide equivalency thus reflects time-integrated radiative forcing. The carbon dioxide equivalency for a gas is obtained by multiplying the mass and the GWP of the gas. The following units are commonly used: a) By the UN climate change panel IPCC: billion metric tonnes of CO2 equivalent (GtCCh eq); b) In industry: million metric tonnes of carbon dioxide equivalents (MMTCDE); c) For vehicles: g of carbon dioxide equivalents / km (gCDE / km).

[0071] For example, the GWP for methane is 21 and for nitrous oxide 310. This means that emissions of 1 million metric tonnes of methane and nitrous oxide respectively is equivalent to emissions of 21 and 310 million metric tonnes of carbon dioxide.

[0072] Various methods exist in the art for calculating or estimating carbon footprints and may be employed in the subject invention.

[0073] Products and processes having a “low-carbon footprint” result in GHGs emitted per unit time that approach net-zero over the full life cycle of producing a system, component or product, through and until the system, component or product is ultimately used by human consumers. The net CO2 and / or other GHG emissions can be, for example, less than about: 50%, 25%, 15%, 10%, 8%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.01%, 0.001% or 0% greater than net-zero emissions.

[0074] In some embodiments, “low-carbon footprint” includes products or processes that result in negative GHG emissions due to, for example, their contribution to CO2 capture.

[0075] In some embodiments, the term “carbon footprint” is interchangeable herein with the terms “carbon intensity” and “emission intensity,” which are measures of the emission rate of a given GHG relative to the “intensity” of a specific activity or industrial process. The emissions intensity can include amount of emissions relative to, for example, amount of fuel combusted, amount of an industrial product produced, total distance traveled, and / or number of economic units generated. Emissions intensity is measured across the entire life cycle of a product. For example, the emissions intensity of fuels is calculated by compiling all of the GHG emissions emitted along the supply chain for a fuel, including all the emissions emitted in exploration, mining, collecting, producing, transporting, distributing, dispensing and burning the fuel.

[0076] Carbon Dioxide Removal Materials

[0077] In preferred embodiments, the CO2-absorbing agent used according to the subject invention is a base. In specific embodiments, the CCf-absorbing agent is calcium hydroxide, calcium oxide, magnesium hydroxide or magnesium oxide. Advantageously, these bases can be made using low carbon-intensity processes.

[0078] In specific embodiments, the CO2-absorbing material is produced by, for example, a low carbon-intensity process. For example, to obtain carbon negative calcium and magnesium oxide / hydroxide, several methods exist. One method utilizes an electrochemical process that uses 100% renewable / green energy and CaCF / MgCE containing brine. Another is a chemical process that uses green inputs for the calcium and magnesium chlorides in the brine to react with and make calcium and magnesium hydroxide. Another option is to use natural sources such as brucite, basalt (both of which naturally contain magnesium hydroxide), or portlandite (which naturally contains calcium hydroxide).

[0079] In the presence of moisture, these compounds react with CO2to produce carbonate salts, which are suitable for disposal in an environmentally-friendly manner.

[0080] For example, the carbonate precipitate can be disposed of by, for example, placement into a landfill, or soil, or utilized as a low-carbon ingredient in cement production. They can also be disposed of in bodies of water, which has the advantage of mitigating acidification of the water.

[0081] The CO2-absorbing agent can be in the form of, for example, pellets or rocks.

[0082] In a preferred embodiment, the base is calcium hydroxide. Calcium hydroxide (or calcium oxide in the presence of moisture) rapidly absorbs CO2in the atmosphere to produce calcium carbonate (CaCCF):

[0083] CaO + H2O Ca(OH)2

[0084] Ca(OH)2+ CO2CaCO3+ H2O

[0085] Calcium carbonate is a common substance found in rocks, most notably in chalk and limestone, eggshells, mollusk shells, shellfish skeletons and pearls, and is considered non- hazardous by the U.S. Environmental Protection Agency (EPA), as well as several regulatory counterparts worldwide. It is also stable at temperatures up to 800°C before it decomposes and re- releases CO2.

[0086] Advantageously, in some embodiments, calcium hydroxide is utilized due to its low carbon footprint. The low carbon footprint character of the calcium hydroxide can be due to, for example, the source of the raw materials used for producing it. The calcium ions that form the calcium hydroxide can be sourced from brine effluents from desalination plants where the salt water is known to have high amounts of calcium ions in its various mineral forms. It can also be sourced from other waste sources, such as limestone-based construction waste, mollusk shells and industrial brine effluents.

[0087] Additionally, calcium hydroxide (and its non-hydrated version, calcium oxide) can be produced using an electrolysis reaction that can readily be powered by 100% renewable energy, such as solar and / or wind.

[0088] In certain embodiments, the chemical base is magnesium hydroxide and its non-hydrated oxide, magnesium oxide. These compounds are similar to calcium hydroxide, but can be more expensive to produce; therefore, in preferred embodiments, additional care is taken to ensure that the compound is produced and obtained using low-carbon footprint methods.

[0089] In certain embodiments, calcium hydroxide and magnesium hydroxide, and their oxide forms, are preferred over other strong bases, such as sodium hydroxide (NaOH) or potassium hydroxide (KOH), which can be highly corrosive and can cause severe bums when contacted with skin, respiratory damage when breathed in, and blindness if contacted with the eye. Additionally, such strong bases could potentially degrade the holding vessel, causing handling issues.

[0090] Furthermore, calcium hydroxide and magnesium hydroxide, and their oxide forms, are more stable than strong bases such as NaOH and KOH and less likely to decompose back to CO2 in mildly raised temperatures and / or in the presence of water.

[0091] In certain embodiments, given the high temperature stability of calcium carbonate and magnesium carbonate precipitates, and their general inert nature, these compounds can serve as carbon sinks when they are, for example, disposed of into landfills, utilized in cementitious materials or applied as soil amendments to improve the fertility of acidic soils.

[0092] Removal of Carbon Dioxide from Enclosed Environments

[0093] The subject invention provides filters that capture and mineralize indoor CO2, and methods of using the filters. The filter can be utilized on its own as a standalone carbon-capture filter or it can be integrated into, for example, a high-efficiency particular air (HEP A) filter or an ultra-low particulate air (ULPA) filter such that it can also function as a filter for collecting particles of air impurities such as, for example, particulate matter and smoke, pollen, mold, dust, airborne pathogens (including viruses such as COVID and the common cold), pet fur and dander, and volatile organic compounds (VOC).

[0094] In certain embodiments, the carbon-capture fdter comprises an air-permeable, or porous, substrate embedded with a CO2-absorbing agent, such as calcium hydroxide and magnesium hydroxide, as described above. The CO2-absorbing agent can be in the form of, for example, loose powder, granules, or pellets, which can be mixed with a substrate or embedded between layers of the substrate.

[0095] The substrate can be synthetic or naturally-derived; however, preferred materials are recycled, re-used and / or biodegradable. The pore size of the fdter substrate can vary between, for example, 0.001 pm to 10 pm, though preferably the pore size is less than about 1 pm, more preferably less than about 0.5 pm, and more preferably less than about 0.3 pm.

[0096] The CC>2-absorbing agent can be added to the substrate in the form of, for example, loose powder or pellets, which can be mixed with the substrate or embedded between layers of the substrate. The ratio of substrate to CCf-absorbing agent within the fdter, by weight, is 1:X or X: 1, where X= a positive integer from 1 to 100,000, from 1 to 75,000, from 1 to 50,000, from 1 to 25,000, from 1 to 10,000, from 1 to 7,500, from 1 to 5,000, from 1 to 2,500, from 1 to 1,000, from 1 to 750, from 1 to 500, from 1 to 250, from 1 to 100, from 1 to 75, from 1 to 50, from 1 to 25, from 1 to 10, or from 1 to 5.

[0097] In certain embodiments, the substrate can be recycled, re-used and / or biodegradable. Nonlimiting examples of substrate materials include non-woven or woven textile, paper, wood, bamboo, glass / quartz wool, honeycomb structured cellulose, activated or porous carbon, zeolites (microporous aluminosilicates), fibers or comminuted materials sourced from plants or agricultural products, such as fibers or comminuted materials sourced from the husks, shells, stems, roots, leaves (or fronds or leaflets), cores, trunks, inflorescences, fruit, pulp, empty fruit bunches, seeds (pit), or the offshoots of various other plants or agricultural products (e.g., the seeds / nuts and / or seed / nut shells or hulls of almond, brazil, cocoa bean, coconut, cotton, flax, grass, linseed, maize, millet, oat, peach, apricot, date pit / date stones, peanut, rye, soybean, sunflower, walnut, wheat; rice straw; rice bran; rice husk including rice husk ash; crude pectate pulp; peat moss fibers; flax; cotton; cotton linters; wool; sugar cane; jute stick; neem leaves; paper; bagasse; bamboo; com stalks; wood / wood chips / wood fibers / wood pulp; bark; straw such as wheat straw; pine cone; cork; dehydrated vegetable matter; whole ground com cobs; com stalks; com cob light density pith core; com cob ground woody ring portion; com cob chaff portion; cotton seed stems; flax stems; wheat stems; sunflower seed stems; soybean stems; maize stems; rye grass stems; millet stems; cellulosic fibers; cellulose; coconut palm materials such as coconut shells, coconut husks; and oil palm materials such as palm oil fuel ash, palm oil fibers, palm oil shells, and palm oil empty fruit brunches); animal-based fibers (e.g., wool); polymers (e.g., biopolymers such as cellulose, lignin, chitosan, starch, polylactic acid, polyhydroxyalkanoates, rubber, gelatin, guar, or xanthan gum); plastics (e.g., bioplastics manufactured using lignin, cellulose, seaweed, algae, sugarcane, fungi, or hemp); metals; resin materials (plastics) such as polypropylenes (PP), polyethylenes (e.g., polyethylene, polyethylene terephthalates (PET), polytetrafluoroethylenes (PTFE), polyvinylidene fluorides, polyimides and polyamide-imides, perfluoralkoxy polymer resins, fluorinated ethylene propylene (FEP), ethylene tetrafluoroethylene (ETFE)); or any existing filter materials.

[0098] In certain embodiments, the air purifier device comprises one or more layers through which the air passes. See FIG. 1. For example, in addition to the carbon-capture filter, the layers can include a pre -filtration layer, a HEPA or ULPA layer, an activated charcoal layer, and / or a fragrance -emitting layer comprising, e.g., essential oils, which are located within the housing downstream from the air inlet. In some embodiments, the pre-filtration layer is contacted with the flowing air first, and may be utilized to filter out larger particles (e.g., 5-10 pm, or greater) of, for example, particulate matter, smoke, pollen, mold, dust, airborne pathogens, pet fur and dander, and volatile organic compounds (VOC). Additional layers can then be situated downstream of the pre-filtration layer to filter out smaller particles.

[0099] In certain embodiments, the filter can be a segmented filter having the CCE-absorbing agent embedded in cells making up various geometric patterns, such as, for example, stripes, checks, or chevron, wherein alternating segments are base-free. Accordingly, after full precipitation of carbonates, air can still pass through the filter by way of the segments that are free of the CCE-absorbing agent.

[0100] In a specific embodiment, the device comprises a housing having a first end comprising an inlet for receiving air, and second end opposite the first end, wherein the second end comprises an outlet for exhausting air. The housing provides an air flow path for the flow of air into the inlet and out of the outlet. In some embodiments, the device utilizes a blower and / or an air induction fan to draw air into the inlet.

[0101] In certain embodiments, the air purifier device comprises within the housing one or more layers positioned across the path of airflow. For example, in addition to the carbon-capture filter, the layers can include a pre-filtration layer, a HEPA or ULPA layer, and / or an activated charcoal layer, which are located within the housing downstream from the air inlet. Preferably, the HEPA or ULPA filter has a MERV rating of 8 or higher, preferably 11 or higher, even more preferably 14 or higher.

[0102] FIG. 2 shows a schematic of a receptacle-type system in which the CCE-absorbing material is placed. It can be in any shape / form, and not necessarily associated with a filter. The carbon-capture filter, whether standalone or integrated, can be located downstream or upstream of particulate filtration.

[0103] In some embodiments, the pre -filtration layer is contacted with the flowing air first, and may be utilized to filter out larger particles of, for example, particulate matter, smoke, pollen, mold, dust, airborne pathogens, pet fur and dander, and volatile organic compounds (VOC). Additional layers can then be situated downstream of the pre -filtration layer to filter out smaller particles. The carbon-capture filter can be located downstream or upstream of particulate filtration.

[0104] The housing can be made of, for example, glass, plastic, polymer, wood, metal, stone or ceramic. Preferably, the housing is a sustainable, recycled, reclaimed and / or biodegradable material, such as, for example, coconut husk, wood, bamboo, plastics (e.g., bioplastics manufactured using lignin, cellulose, seaweed, algae, sugarcane, fungi, or hemp) and / or metals.

[0105] The dimensions of the housing can depend upon the environment in which it is used. For example, the efficiency of an air purifier is measured in cubic feet per minute (CFM), where the CFM value indicates how many cubic feet of air the purifier can turnover per minute. Typically, about 100 CFM is required for each 250 square feet of space in an environment.

[0106] In one embodiment, the subject invention utilizes a refillable receptacle system that can be positioned in an air flow path or forced air systems such as HVAC, vacuum cleaners and the like. This can be, for example, a deep perforated bowl or a deep rectangular shaped receptacle that contains the CCF-absorbing agent. Some water can be introduced in the form of, for example, a spray (either built into the air purifier or external).

[0107] In some embodiments, the air purifier comprises a display for turning the device on and off, and / or for controlling the speed of air flow through the system. The device can also contain a means for detecting when a filter or layer within the device requires replacement, as well as an indicator, such as a light or alert for the same.

[0108] Furthermore, in some embodiments, the device can comprise an indicator providing users with a measure of the total amount of CO2 captured through use of the device, further taking into account the carbon footprint of producing and powering the device. This information can also be transmitted to a mobile application through a wireless network communication, so that users might also see their total CO2 captured and the cumulative CO2 captured by users of the device across the world.

[0109] Further provided herein are methods for filtering air of particles while simultaneously absorbing CO2 from the atmosphere using a carbon-capture filter of the subject invention. In some embodiments, the method is passive, wherein the filter is placed in an enclosed environment having access to airflow and simply left in place for a period of time until all of the CO2- absorbing agent has been converted to carbonate salt.

[0110] In certain embodiments, the method is active, wherein the filter is placed in an electrically-powered device that moves air, such as an air purifier, an HVAC system, a window A / C unit, an automobile heating and A / C unit, a vacuum cleaner, a hair dryer, or a fan. Air is then induced to pass directly through the filter by way of operation of the air-moving device for a period of time until all of the CCf-absorbing agent has been converted to carbonate, and / or the filter has become saturated with particulate impurities. The filter can be placed at a location in the air-moving device such that outbound flowing air passes through the filter, such as, for example, a vent or exhaust opening.

[0111] Preferably, the air-moving device is powered using renewable energy, such as solar energy, hydropower, wind energy or geothermal energy, and / or a rechargeable battery powered by a renewable source of energy. In certain embodiments, the methods utilize an air purifier device described herein.

[0112] Advantageously, the subject invention can be utilized by individuals in their homes and businesses as an everyday source of air filtration and as a way to contribute towards efforts to reduce atmospheric greenhouse gases through Direct Air Capture (DAC). Furthermore, the subject invention can be adapted for use in home appliances.

[0113] In some embodiments, the carbon-capture filter comprises a means for placing the filter into an environment containing CO2. For example, in one embodiment, the filter comprise a means for affixing the filter to a source of air flow. The filter can be placed into a container through which air is capable of passing, wherein the container is affixed to, or within, for example, a trash can, a wall or cabinet, aromatherapy diffuser, an air purifier, an air filter, an engine filter, a HVAC system, a window A / C unit, a vacuum cleaner, a hair dryer, a fan or a vent. The container can be affixed using, for example, adhesive, a clip, screws, nails, or other known fasteners, depending upon the location.

[0114] In some embodiments, the filter can be permanently affixed at a location, and the filter can then be exchanged for a new filter once the carbonates are saturated. In other embodiments, the filter and the means for affixing the filter are permanently joined such that when the filter requires replacing, the entire package is removed and disposed of. Advantageously, the methods of the subject invention can be utilized to reduce the levels of CO2 in an enclosed environment, thereby contributing to reduced atmospheric GHG as well as reducing potential health effects that can result from excess ambient CO2, such as, for example, headaches, dizziness, breathing difficulty, increased heart rate, elevated blood pressure, asphyxiation, eye irritation, sore or dry throat, rhinitis, sneezing, and / or coughing.

[0115] In certain embodiments, once the base has been completely converted into carbonate, the methods can further comprise disposing of the carbon-capture filter and / or its contents.

[0116] In certain embodiments, the carbon-capture filter is them replaced with a new loaded carbon-capture filter comprising a fresh C Ch-absorbing material. Advantageously, in some embodiments, the carbonate precipitate can serve as a carbon sink, effectively sequestering CO2 in, for example, landfills, soil or cementitious materials.

[0117] Removal of Carbon Dioxide from Biogas Emissions

[0118] The technology of the subject invention can also be utilized for CO2 removal from medium to large scale CO2 emitters, such as biogas plants. These plants use biomass from, for example, manure, agricultural waste, wastewater and trash to make biogas, which is typically a combination of methane, CO2 and H2S. The ratio of CH4 to CO2 can be, for example, 80:20 to 50:50 depending upon the age of the plant and the type of feedstock.

[0119] The biogas that is produced in such plants is often burned to produce electricity; however, because of increasing concerns of CO2 emissions, it would be advantageous to capture and dispose of the CO2. Current methodologies for such capture and disposal typically involve capturing CO2, which is put in water and then either used as input stock for industrial use (e.g., carbonation of drinks and conversion to plastics), or shipped to a permanent underground storage location.

[0120] This is not an efficient process because of the expense and carbon utilization associated with shipping the CO2 to a distant storage facility and pumping it into a location with the hope that it will remain there.

[0121] In accordance with the subject invention, an end product that is valuable in, for example, pharmaceuticals, food, agriculture and construction is created. In preferred embodiments, the carbon capture system is carbon negative (by, for example, utilizing a waste source and also green energy), which makes it very beneficial to the environment.

[0122] In one embodiment, biogas (preferably after going through a H2S scrubber to remove H2S that would otherwise react with Ca(OH)2 and Mg(OH)2) is sent in a forced stream through the CC>2-absorbing agent of the subject invention, which rapidly absorbs the CO2 and turns it into its carbonate forms. Temperature can be adjusted to achieve the most cost-effective mineralization rate to capture and store CO2 emissions (e.g., a 15 metric ton capture and storage system can cater to an average-sized biogas plant in Germany that produces 4,000 metric tons of CO2 per year).

[0123] The remaining stream is purified methane, which can be piped to collection points and then processed later to turn it into green hydrogen to, for example, be used in the manufacture of plastics or combusted to make electricity.

[0124] A schematic depiction of the capture of CO2 from biogas plants is shown in FIG. 3.

[0125] An example of this embodiment uses customized trucks to take the CCf-absorbing material from where it is made (typically near a desalination plant or salt production facility), to a biogas plant where it is connected to the biogas stream. After the carbonate precipitation is complete (optionally using sensors to check the rate), the truck drives to where the carbonates will be used. A different truck can then check into the pad to continue the process. The trucks can be electric to reduce the footprint of this operation. This system is advantageous compared to shipping water with CO2 many miles to far away storage sites.

[0126] Removal of Carbon Dioxide from Shipping Exhaust

[0127] A further embodiment of the subject invention involves the shipping industry, where removal of CO2 from the exhaust of a water-borne vessel can help reduce the carbon footprint of operating the ship.

[0128] Shipping is a hard-to-abate sector; every opportunity to reduce the carbon footprint is beneficial. As the primary transport option of global commerce, millions of vessels handling freight and / or passengers call on ports around the world each year. Even with significant investment in abatement technologies, GHG emissions are still projected to increase from 2025 levels.

[0129] Large water-borne vessels, such as cruise ships, ferries, cargo ships / freighters and naval ships, often have a desalination plant, which provides potable water for the passengers and the ship’s operation, and also an onboard source of brine.

[0130] Using green energy from onboard sources (e.g., Magnus turbines, solar power, and wave action), the CCf-absorbing material (e.g., calcium hydroxide or magnesium hydroxide) can be created.

[0131] Waste heat from various shipboard processes can be used to accelerate the mineralization rate so that larger volumes of CO2 can be captured. For example the ship engine and / or compressor are readily-available sources of heat. Waste heat from the engine can be leveraged to accelerate mineralization rate, and consequently the amount of CO2 captured. The temperature can be adjusted to achieve the most cost-effective mineralization rate to capture and store CO2 emissions.

[0132] Calcium and Magnesium Hydroxide can be produced in large enough quantities and poured into made-for-purpose baffles in which they absorb exhaust CO2 and turn it into carbonates.

[0133] The CC>2-absorbing material can then be placed in the exhaust stream of the ship using the materials and methods described herein. The resulting high purity carbonates can be stored and sold at shore, or delivered into the ocean. Because the carbonates are alkaline, they can help counter the ongoing acidification of the ocean (due to climate change).

[0134] The other byproduct of production is bleach, which can be used for cleaning the ship, or have the excess sold at shore as a high purity, very low carbon product

[0135] The oceans absorb 30% of all emitted CO2 (as part of the carbon cycle). Oceans are getting increasingly acidified (going from 8.15 to 8.05 between 1950 and now, and accelerating further), which negatively impacts ocean life and fisheries; therefore, the addition of the alkaline carbonates is good for the marine environment.

[0136] There are international efforts and carbon credits available to encourage maintaining the alkalinity of the oceans. Carbonates are naturally alkaline and are already a part of the ocean ecosystem, hence, dumping them overboard helps the ocean health and, through carbon credits and grants, provides a revenue source for the operator.

[0137] The technology of the subject invention is different from conventional carbon capture and utilization systems, especially alkaline-based ones, because the subject invention utilizes green energy to make the alkaline absorbents from a waste source (e.g., desalination water brine or salt production waste water brine). Thus, the captured / precipitated CO2 in the form of carbonate is carbon negative and does not need to be then transformed into another medium for transport and ultimate storage. Alkaline absorbents such as NaOH, KOH, Ca(OH>2 and Mg(OH)2 are normally manufactured in a carbon intensive manner, thus their use is strictly reduced to capturing the CO2 in closed loop systems.

[0138] A schematic depiction of the capture of CO2 from ship exhaust biogas plants is shown in

[0139] FIG. 4 EXAMPLE 1: Removal of CO2 from Passenger Ship Exhaust

[0140] Large ships have large desalination plants to cater to its passengers, which in turn provides substantial volumes of brine.

Claims

CLAIMSWe claim:

1. An air filter for reducing atmospheric carbon dioxide in the air, comprising a CO2- absorbing agent embedded in an air-permeable substrate, wherein the CCf-absorbing agent is a base selected from calcium hydroxide, calcium oxide, magnesium hydroxide and magnesium oxide; wherein the substrate is a reclaimed, recycled and / or biodegradable air-permeable material; wherein the substrate has a pore size of 0.001 pm to 10 pm; and wherein the base is embedded in the substrate in the form of a loose powder, pellets or beads.

2. The air filter of claim 1, wherein the filter comprises cells that contain the base, which alternate with cells that do not contain the base.

3. An air purifying device for reducing atmospheric carbon dioxide in the air while simultaneously removing a contaminant particle from the air, the device comprising a housing having a first end and a second end, wherein the first end comprises an inlet and the second end comprises an outlet, wherein the first end comprises a blower and / or a fan for inducing the flow of air into the inlet and directing the air through the housing towards and out of the outlet, and wherein the device further comprises an air filter according to claim 1 positioned within the housing such that the air passing from the inlet towards the outlet contacts the air filter.

4. The air purifying device of claim 3, further comprising one or more additional layers positioned within the housing such that the air passing from the inlet towards the outlet contacts the one or more additional layers, wherein one or more of the layers is selected from a prefiltration layer, a HEPA layer, an ULPA layer, an activated charcoal layer and a fragrance layer.

5. The air purifying device of claim 3, wherein the device is powered using a source of renewable energy or a rechargeable battery that is charged using a source of renewable energy.

6. The air purifying device of claim 3, comprising a wireless network connection that can be connected to a mobile application such that users can track how much carbon dioxide has been captured through operation of the device.

7. The air purifying device of claim 3, wherein production and operation of the device results in negative net-carbon dioxide emissions.

8. A method for removing a contaminant from air in an enclosed environment and simultaneously capturing CO2 from the air, the method comprising placing a carbon capture fdter according to claim 1 into the environment such that air from the environment flows through the fdter.

9. The method of claim 8, wherein air is forced through the fdter by an air-moving device.

10. The method of claim 8, wherein the fdter is left in the environment until all of the CO2- absorbing agent has been converted to carbonate.

11. The method of claim 10, wherein the method further comprises disposing of the carbonate and / or the fdter comprising the carbonate in a landfill, in soil and / or in a cementitious material to sequester carbon therein.

12. A method for removing CO2 from a biogas stream wherein said method comprises contacting the biogas stream with a CCf-absorbing agent selected from calcium hydroxide, calcium oxide, magnesium hydroxide and magnesium oxide.

13. The method according to claim 12, wherein, before contacting the biogas stream with said CC>2-absorbing agent, H2S is removed from the biogas stream.

14. The method according to claim 12, wherein the C Ch-absorbing agent is CaOtT or MgOIT and, as a result of the removal of CO2 from the biogas stream by said CCf-absorbing agent, calcium carbonate and / or magnesium carbonate is formed.

15. The method according to claim 14, wherein the CaOH2and / or MgOH2is produced using a low carbon-intensity method.

16. The method according to claim 12, wherein heat produced by a biogas facility is used to heat the biogas stream that is contacted with said CCf-absorbing agent.

17. The method according to claim 14, wherein said calcium carbonate and / or magnesium carbonate is stored in a landfill, used in agriculture, used in livestock production, used as a health supplement and / or disposed of in a body of water.

18. The method according to claim 17, wherein the method, from production of the CO2- absorbing agent through disposal / use of the calcium carbonate and / or magnesium carbonate is carbon negative.

19. A method for removing CO2 from an exhaust from a ship wherein said method comprises contacting the exhaust with a CCf-absorbing agent selected from calcium hydroxide, calcium oxide, magnesium hydroxide and magnesium oxide.

20. The method according to claim 19, wherein, before contacting the exhaust with said CO2- absorbing agent, soot is removed from the exhaust.

21. The method according to claim 12, wherein the CCf-absorbing agent is CaOl or MgOlT and, as a result of the removal of CO2 from the exhaust by said CCT-absorbing agent, calcium carbonate and / or magnesium carbonate is formed.

22. The method according to claim 14, wherein the CaOlT and / or MgOlT is produced using a low carbon-intensity method.

23. The method according to claim 14, wherein heat produced by the ship is used to heat the exhaust that is contacted with said GCA-absorbing agent.

24. The method according to claim 14, wherein said calcium carbonate and / or magnesium carbonate is stored in a landfill, used in agriculture, used in livestock production, used as a health supplement and / or disposed of in a body of water.

25. The method according to claim 17, wherein the method, from production of the CO2- absorbing agent through disposal / use of the calcium carbonate and / or magnesium carbonate is carbon negative.

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