Device composed of modules and integrated process for the capture of carbon dioxide from atmospheric air or gas mixtures, using alternative adsorbents

Abstract

The present invention relates to a device featuring three assembly configurations and respective processes for carbon dioxide (CO2) removal in direct air capture (DAC) applications from indoor and outdoor environments, and / or concentrated CO2 streams such as biogas and combustion gases. The device is formed by modules in boxes or columns containing desiccant material and adsorbents derived from chitosan and other biomasses, operating as coupled units that function simultaneously. Furthermore, the column arrangement allows for the capture of CO2 from stationary emission sources such as biogas mixtures and combustion gases. One of the invention's differentiators is being a multifunctional process that, in addition to capturing CO2 from gas mixtures with CO2 removal efficiency in the range of 75 – 100%, also removes particulate matter and other atmospheric pollutants. Another differentiator is the utilization and valorization of biomass and waste for the production of adsorbent materials. The invention also comprises a modular configuration with removable cartridges, integrated sensors, and thermal and / or pressure swing regeneration. Additionally, the captured CO2 can be directed to an aqueous mineralization system containing a CaCl2 solution alkalized with NH4OH or MEA, with or without combination with a membrane or chitosan beads, resulting in the formation of high-purity calcium carbonate (CaCO3).

Description

DEVICE COMPOSED OF MODULES AND INTEGRATED PROCESS FOR THE CAPTURE OF CARBON DIOXIDE FROM ATMOSPHERIC AIR OR GAS MIXTURES, USING ALTERNATIVE ADSORBENTSRELATED APPLICATIONS

[0001] This application claims priority to BR Patent Application BR102024014910-6, filed on July 19, 2024, the entire content of which is hereby fully incorporated by reference.Field of the invention

[0002] The present invention relates to a device that has three assembly configurations and its process for removing carbon dioxide (CO2) for Direct Air Capture (DAC) applications from indoor and outdoor environments, or from gas mixture streams. The device uses solid CO2 removal adsorbents, particularly through a CO2 capture module integrated into a storage unit for subsequent direct use or transformation of CO2, enabling its application in the agribusiness, energy, civil construction, pharmaceutical, among other sectors.Background of the Invention

[0003] Carbon dioxide is a fundamental component for the development of life on the planet. However, due to high emissions into the atmosphere, mainly from the burning of fossil fuels, CO2 has become a serious environmental problem as it is considered a primary factor in the intensification of global warming and, consequently, a threat to humanity and nature.

[0004] According to the Intergovernmental Panel on Climate Change (IPCC) , atmospheric CO2 levels have increased by more than 40% over the past centuries, from 280 ppm in the pre-industrial period to levels above 400 ppm, with a corresponding increase in the planet's average temperature of around 1.0 °C. Carbon capture was proposed by the IPCC in 2005 as a necessary technology to slow the growth of atmospheric CO2 concentrations. Over the years, various capture methods have been proposed and developed. Carbon Capture, Utilization, and Storage (CCUS) is a set of technologiesnecessary to enhance the reduction of CO2 concentration in the atmosphere .

[0005] Conventionally, carbon dioxide capture is considered for emissions from large sources, such as fossil fuel power plants, cement factories, oil refineries, and steel mills. In these cases, capture processes are based on gas separation in pre-combustion, post-combustion, and oxy-combustion .

[0006] Furthermore, recently, technologies have been developed for carbon control from the atmosphere, called DAC . In this case, capture processes are dissociated from thermal power plants and industrial facilities, consisting of passing atmospheric air through a system containing the sorbent for CO2 removal.

[0007] Existing technologies for carbon dioxide removal are diverse, involving absorption, adsorption, cryogenic separation, and membrane separation methods. CO2 absorption, using amine solutions such as monoethanolamine (MEA) and diethanolamine (DEA) , is considered the most industrially mature capture technology. Absorption involves contacting the gas stream with the amine solvent. While CO2 has a higher affinity for the liquid phase, other gases form the system's outlet gas stream with low CO2 concentration. Subsequently, the solvent is regenerated by heating and depressurization, promoting the recovery of pure CO2.

[0008] Adsorption technology has gained relevance in recent years due to its operational advantages, including increased life cycle, enhanced regeneration capacity, and reduced energy costs. The adsorption method involves separating CO2 through the use of adsorbents. The CO2 can be adsorbed on different materials, including activated carbons, zeolites, Metal Organic Frameworks (MOFs) , and amino-functionalized solids.

[0009] As an example of adsorbent materials, the patent document BR 112014027575-0 addresses the removal of greenhouse gases from the atmosphere and, in particular, systems and methods for removing carbon dioxide from a gas stream, including ambientair, applying amino-functionalized porous solids containing condensed water in the pores. In this method, adsorbent regeneration occurs at 120 °C and involves vaporization of water from the pores at low pressure, followed by CO2 collection and water condensation in the solid pores for the next adsorption cycle. However, in the process, amine leaching and consequently a reduction in adsorbent efficiency may occur.

[0010] The patent document BR 112022025426-1 describes the use of adsorbents in a process for DAC application. The materials described are inorganic or organic, non-polymeric or polymeric, in particular crosslinked polystyrene sorbents, functionalized with amino groups, exhibiting a specific surface area in the range of 1-20 m2.g-1, preferably additionally a pore volume in the range of 0.05-0.50 cm3.g-1and / or preferably a pore diameter between 50-300 nm and / or preferably a nitrogen content expressed in wt% in the range of 5-50%.

[0011] In one aspect, the present invention differs from the patent document BR 112022025426-1 by applying biochar derived from chitin, chitosan, and other biomasses, impregnated or unimpregnated with amine solutions, exhibiting specific surface areas in the range of 300 - 2,000 m2.g-1, pore volume in the range of 0.01 - 0.9 cm3.g-1, pore diameter in the range of 20 - 200 nm, and nitrogen content expressed as mass percentage in the range of 1 - 10%.

[0012] The patent document BR 112022025426-1 describes the regeneration of adsorbent materials using saturated or superheated steam injection to induce a temperature increase within a range of 60-110 °C. Although saturated or superheated steam injection can be a viable option in certain situations, its disadvantages, including complexity and high energy demand, may make it less attractive. In one aspect, the invention presents a system of internal resistors or heated fluid pipelines inside the devices for more direct and controlled heating, using energy more efficiently and minimizing potential sources of materialcontamination. The combination with device evacuation also enables more complete regeneration, ensuring the efficient removal of adsorbed gases.

[0013] The patent documents BR 102018003076-0 and BR 102014 009903-4 used biomass waste to produce solid carbon dioxide adsorbent material, specifically banana leaf ash and sugarcane bagasse, respectively. The ashes were used as a silicon source to synthesize zeolites, such as LTA zeolite, by alkaline leaching and hydrothermal synthesis methods, with an adsorption capacity of up to 2.9 mmol CO2.g-1. A type A zeolite was obtained from silicon extraction from sugarcane bagasse ash by alkaline fusion and hydrothermal synthesis, and has an adsorption capacity of 5.05 mmol of CO2. g-1zeolite. In one aspect, the invention differs from these described documents because the materials are synthesized by hydrothermal treatment and chemical activation of chitosan and other biomasses, impregnated or unimpregnated, and have CO2 adsorption capacity up to 5.5 mmol.g-1under ambient conditions.

[0014] Once carbon dioxide is separated from other gases, as performed in absorption with amines and other basic solutions, such as in atmospheric air and combustion gases, two main approaches regarding its final disposal have gained prominence over the years: storing it or utilizing it. Historically, the concept of Carbon Capture and Utilization (CCU) has been proposed as a complementary technology to Carbon Capture and Storage (CCS) , aimed at decreasing CO2 emissions and lowering fossil resource consumption .

[0015] The CCU technology can be applied to limit CO2 emissions by utilizing this gas as a raw material in the production of chemical products, or for direct use by the food or cement industries, for example. The captured CO2 can also be applied for the production of synthetic fuels through its processing with renewable hydrogen. In this sense, CCU can, therefore, help integrate the natural gas sector with renewable energy.

[0016] However, CCU processes face several operational and logistical limitations, mainly concerning the costs associated with sorbent regeneration and chemical transformation, which require high energy. The thermodynamic stability of the CO2 molecule makes the integration of capture and utilization processes of this gas difficult.

[0017] The patent document BR 112022021340-9 addresses CCU, wherein direct air capture associated with hydrogen produced by water electrolysis converts CO2 into fuels and chemicals. The product consists of hydrocarbons containing 4 to 24 carbons; additionally, other alternative products can be produced, such as methanol and ammonia. The capture material used can be amine- supported on polymers or oxides (typically silica) , such as tetraethylenepentamine or diethanolamine, both of which are impregnated on MCM-41 silica.

[0018] Beyond the environmental issue discussed above, it is noteworthy that the indoor environment, especially in enclosed buildings, has a higher carbon dioxide level than the outdoor environment, due to high occupancy by people combined with insufficient air renewal. According to research from the International Journal of Indoor Environment and Health, average CO2 concentrations in these environments generally vary between 600 and 1000 ppm, but can exceed 1500 ppm (K. Azuma et al., Environment International 121 (2018) 51-5) .

[0019] It is also noted that high concentrations of CO2 have adverse effects on human health, causing fatigue, headaches, nausea, and drowsiness, among other issues. Consequently, these discomforts lead to a reduction in people's productivity due to a temporary partial loss of cognitive abilities. A study conducted by the National Institute of Environmental Health Sciences assessed the impact of indoor air quality on employees' cognitive abilities. It concluded that people exposed to 1400 ppm of CO2 reduced their cognitive scores by 10% in skills such as strategyand information use (Nature Sustainability, 2019, vol. 2, pp . 691- 701) .

[0020] The primary mechanisms for CO2 attenuation in the internal environment include opening windows, when possible, and the insufflation of external air through axial and centrifugal fans, with filters incorporated into the air conditioning system. However, mechanisms in enclosed buildings with high people flow require conditioning of external air, resulting in high energy costs .

[0021] According to the US Environmental Protection Agency Heating, Ventilation and Air Conditioning, 40% of building energy costs are related to the heating, ventilation, and air conditioning (HVAC) system (Energy and Buildings, 2008, v. 40, 394-398; Energy and Buildings, 2018, v. 173, 562-576) . Thus, the implementation of CO2 capture technologies in indoor environments can generate benefits, considering the potential reduction of energy costs through decreased air conditioning operations, as well as a reduction in carbon emissions from buildings resulting from energy consumption .

[0022] As an example of technologies applied to indoor environments, the patent document BR 112013029302-0 includes the provision of a supported sorbent that acts to reduce CO2 from the air in an indoor environment, including an amine-based sorbent. There is the formation of a stream containing CO2 captured from within an enclosed environment. The process includes providing sorbent and support in communication with a heating, ventilation, and air conditioning (HVAC) system.

[0023] The patent document KR 10-2221734 describes a CO2 capture system for an indoor environment containing an adsorbent with amine functional groups and a magnetic body to perform CO2 adsorption and desorption cycles. The regeneration of this adsorbent material is achieved by heating, with heat generated by electromagnetic induction within the magnetic body. The regeneration temperature is in the range of 100-110 °C.

[0024] The patent document JP 2006-061758 describes a device that contains a medium for adsorbing carbon dioxide from indoor air, in which this adsorbent medium comprises a material with a functional group for selective CO2 adsorption. These materials include resins and complexes with functional groups for selective adsorption, in addition to chitosan and ion-exchange resins. The regeneration of these materials is achieved by heating to temperatures of up to 150 °C.

[0025] The patent document KR 10-0764601 describes a process in an indoor environment involving a device and various gas mixture passage configurations capable of capturing CO2, as well as other gases such as CO, through adsorption. The material used in this device is a silica-based molecular sieve, and its regeneration is achieved by heating to a temperature range of 60-100°C.

[0026] The inclusion of multiple gas mixture passage configurations, as described in document KR 10-0764601, can result in an irregular distribution of gases within the device, which can compromise CO2 capture efficiency. Furthermore, the assembly and integration of these different paths can increase the system's complexity, making it more challenging to manufacture, install, and operate on a commercial scale. In contrast, the present invention presents a device with a single regular path for the passage of the gas mixture between the modules, generated by fan arrangements positioned at the inlet and outlet, which offers the possibility of operating at different flow rates in a simpler and more direct approach, facilitating industrial-scale implementation .

[0027] The patent document CN 111375286 describes a process for capturing and utilizing CO2 from systems connected to indoor / enclosed air conditioning. This device features an adsorption plate specially configured to attract and retain CO2 present in ambient air. Additionally, the device contains a heating element positioned to heat the adsorption plate, thereby allowing the release of adsorbed CO2. The adsorbents used can be aminessupported on silica, and after the capture process, CO2 is recovered by heating using the hot exhaust gas from the air conditioner itself.

[0028] The patent document CN 111375286 contains only arrangements of adsorbent plates in parallel, while, in one aspect, the present invention refers to a device for CO2 capture that stands out for its improved efficiency and performance. Furthermore, in another aspect, the present invention incorporates both a CO2 capture module and a desiccant module, as well as a heating system integrated directly into these modules. This configuration allows for uniform heat distribution throughout the solid adsorbent, resulting in more effective regeneration. Additionally, the presence of a heating system in the modules themselves significantly contributes to reducing the time required for complete adsorbent regeneration. Thus, the device provides more efficient CO2 capture from the air, with reduced regeneration times and more optimized operation.

[0029] The patent document US 2023 / 0233989 Al describes a direct air capture system and method with CO2 and water separation. The apparatus has an atmospheric water extraction unit followed by a CO2 capture unit, and can operate reversibly with another similar set, allowing one set to operate in separation mode while the other set operates in regeneration mode. The solid CO2 adsorption material can be inorganic, organic, or a combination of both.

[0030] In one aspect, the invention differs significantly from patent document US 2023 / 0233989 Al. In addition to the distinct arrangement of the apparatuses, the invention offers the possibility of operating with higher CO2 concentrations as input, such as combustion lines and biogas, while the reported document uses a DAC source for CO2 separation. While the reported document operates reversibly, i.e., one stage operates in adsorption and the other operates in regeneration, in one aspect, the present invention can be operated reversibly and can be operated in series, meaning the second module is fed with the outlet stream of thefirst module, and thus both modules operate in adsorption mode or both modules operate in regeneration mode.

[0031] Furthermore, the reported document operates with storage of the CO2 recovered in the process, while, in one aspect, the present invention allows for the storage of separated CO2 and enables the CO2 to be directed to a mineralization column that will transform it into carbonates, which have applications in food and as fertilizers, for example.

[0032] With average operating costs of US$600 per ton of captured CO2, the CO2 capture processes, especially DAC processes, are still considered economically unviable. In addition to operating costs, most processes utilize toxic, high-cost, and fossil-derived adsorbent materials, and the process itself consumes a significant amount of energy and installation space.

[0033] Therefore, in one aspect, the invention highlights a multifunctional process for CO2 capture from gas mixtures, from atmospheric air in indoor or outdoor environments, or from emission sources, carried out in a device composed of integrated modules for captured CO2 removal, in addition to other gases and water vapor. In the process, adsorbent materials derived from biomass, functionalized or impregnated with amines, with CO2 adsorption capacity and CO2 selectivity are applied. The CO2 separation modules are compact and present regeneration conditions by combining heating and depressurization of the system, operating dynamically between CO2 capture and regeneration.

[0034] The CO2 capture system has a CO2 storage unit, opening possibilities for CO2 transformation and use at the point of application. Additionally, the capture device is suitable for use in both indoor and outdoor environments, as well as in industrial processes .Brief Description of the Drawings

[0035] Figure 1 presents a process diagram with possible applications of the system for capture in indoor environments,such as rooms, offices, cafeterias, airports, museums, buildings, with a sterilization and dehumidification step. For outdoor applications such as avenues, highways, fields, regions near industrial facilities, the dehumidification step is also necessary. Finally, for application in industrial emission sources, a pre-treatment step of the process gas is needed for the removal of particulate matter and acid gases (NOx and SOx) . For all these CO2 capture applications, regeneration steps, represented by desorption, and storage of the captured CO2 apply.

[0036] Figure 2 presents the top view of one embodiment of the interior of the carbon dioxide capture device for atmospheric air applications in indoor (Figure 2a) and outdoor (Figure 2b) environments. Featuring the arrangement of inlet fans (1) ; sterilization device (2) ; desiccant module (3) and adsorbent modules (4) ; device outlet (5) ; system exhaust fan (6) . The device is understood as the equipment, and the modules as an integral part of the device.

[0037] Figure 3 represents one embodiment of the desiccant (3) and adsorbent (4) modules of the device containing solid materials arranged inside the modules for water removal and CO2 capture, respectively, from atmospheric air, also represented in Figures 2a and 2b. Figure 3 also presents one embodiment of the device's heating system containing resistance or pipelines for the passage of heated fluids (7) , and the temperature sensor / thermocouple (8) .

[0038] Figure 4 presents an example of a flowchart containing the CO2 capture device (9) , which is composed of the gas treatment and separation steps, and adsorbent regeneration, integrated with the CO2 storage and utilization module (13) , containing a condenser (10) , a compressor (11) , and valves (12) . This flowchart is applicable to both the box-type capture device (Figure 2) and the column-type (Figures 5 to 7) .

[0039] Figure 5 presents one embodiment of the pre-treatment system, which has an arrangement of three columns: (14) , (15) , and (16) . This system is connected to the desiccant (17) and CO2 capture(18) modules and is applied in the pre-treatment of the gas mixture when CO2 capture is derived from industrial process gases.

[0040] Figure 6 presents one embodiment of the carbon dioxide capture device with column modules for industrial process gases and DAC applications. The arrangement of capture modules in columns can be in series (Figure 6a) , where the feed stream from the desiccant module (17) enters the first adsorbent column (18) and the outlet stream from this column enters the second adsorbent column (18) . There is also a parallel arrangement of column capture modules (Figure 6b) , where the feed stream enters the first desiccant module (17) and proceeds to the first adsorbent column (18) , and a distinct feed stream from the first modules enters the second desiccant module (17) and proceeds to the second adsorbent column (18) (Figure 6b) .

[0041] Figure 7 presents one embodiment of the carbon dioxide capture device with column modules for DAC application, highlighting the use of a fan coupled to the outlet of a lid that contains valves connecting to the piping leading atmospheric air into the columns.

[0042] Figure 8 presents one embodiment of the carbon dioxide capture device, with box modules for DAC application, and exhaust gases with hoods that direct the gas inlet to the internal space containing the adsorbent, as well as an outlet hood.

[0043] Figure 9 presents a graph relating the CO2 adsorption capacity of biochar derived from the activation of chitosan hydrochar (CAHTCQ700) and activated chitosan biochar (CAQ700) compared to chitosan and chitosan hydrochar (HTCQ) as a function of adsorption time.

[0044] Figure 10 presents a graph comparing the CO2 adsorption capacity of impregnated pelletized biochar (CIP) with that of activated chitosan biochar (CAQ700) as a function of adsorption time .

[0045] Figure 11 presents a graph of CO2 adsorption capacity data for CHIT-CAQ700-t materials, where t represents the contact time of chitosan with activated carbon in the preparation of the adsorbent material via the impregnation method.

[0046] Figure 12 shows the behavior of the gas mixture in fixed- bed column adsorption, with the outlet coupled to a mass spectrometer. The bed was formed from commercial activated carbon (a) or 5CHIT-CIP-280 (b) .

[0047] Figure 13 presents a graph of CO2 removal efficiency of the prototype column arrangement fed in series as a function of adsorption time. Gas mixture passage process with composition 0.1% CO2, 21.9% O2, and 78.0% N2 at a flow rate of 30 L.tr1at 25 °C.

[0048] Figure 14 presents a graph of CO2 removal efficiency of the box arrangement prototype as a function of adsorption time. Gas mixture passage process with composition 0.1% CO2, 21.9% O2, and 78.0% N2 at a flow rate of 50 mL.min-1at 25 °C.

[0049] Figure 15 presents a graph of calcium carbonate yield in mineralization tests using different aqueous media: CMEA - calcium chloride + MEA; CNH1 - calcium chloride + IM NH4OH; CNH1MEA - calcium chloride + IM NH4OH + MEA; CMB - calcium chloride + chitosan membrane; CMBNH1 - calcium chloride + chitosan membrane + IM NH4OH; CMBMEA - calcium chloride + chitosan membrane + MEA; CMBNH1MEA - calcium chloride + chitosan membrane + IM NH4OH + MEA.Description of the Invention

[0050] In some embodiments, the present invention describes a device with arrangements of: (i) modules in boxes for DAG applications in atmospheric air from indoor or outdoor environments, (ii) in adsorption columns for applications in industrial process streams, or DAG applications, and its carbon dioxide separation process, or (iii) in box modules with massive adsorbent filling. Such a capture device contains modules with desiccant materials and modules with adsorbents for CO2 capture, and is integrated into the CO2 storage or utilization module.

[0051] In the context of the present disclosure, "desiccant" is understood as any solid material of hydrophilic nature capable of retaining moisture present in the gas mixture fed to the device. Examples of desiccants include Type A zeolites, alumina, silica gel, and calcium chloride. The higher the desiccant's ability to remove moisture, the smaller the amount needed, potentially reducing the size and number of modules.

[0052] "Adsorbent" is understood as any porous solid material capable of selectively capturing carbon dioxide present in the gas mixture fed to the device. In one aspect, the present invention developed and applied adsorbents derived from chemical activation or hydrothermal treatment of chitin, chitosan, and other biomasses, functionalized with amino groups or impregnated with amine and polymeric solutions, exhibiting a specific surface area in the range of 300 - 2000 m2.g-1, pore volume in the range of 0.01 - 0.9 cm3.g-1, pore diameter in the range of 20 - 200 nm, nitrogen content expressed as mass percentage in the range of 1 - 10%, and CO2 adsorption capacity in the range of 0.7 - 5.5 mmol.g-1under ambient conditions. These adsorbent materials are efficient and robust for CO2 capture processes within adsorption and desorption cycles .

[0053] In addition to the aforementioned adsorbent materials, adsorbents such as activated carbon, zeolites, aminofunctionalized materials, Metal-Organic Frameworks (MOFs) , metal oxides, amine-modif led silica gel, aerogels, and mesoporous silicas can be applied.

[0054] In one embodiment of the present invention, the composition containing carbon dioxide in the gas stream fed to the system comprises the range of 0.04 - 0.1% CO2 (mass ratio) for direct atmospheric air capture applications in indoor or outdoor environments. The inlet air stream can also contain CO2 concentrations in the range of 10 - 60% CO2 (mass ratio) in stationary source CO2 capture processes, i.e., industrial gas streams. The inlet gas mixture flow rate can vary from 0.02 - 1000m3.h-1, considering the control of the residence time of the mixture in the system as a function of the module format (box or columns) and unit dimensions, and the characteristics of the adsorbents.

[0055] In one embodiment, the present invention features a CO2 capture device in a box format (Figure 2) comprising an external structure, in the form of a rectangular cabinet, made of stainless steel, and internally composed of two distinct parts: a desiccant module and an adsorbent module.

[0056] In one embodiment, the modules are constructed in the shape of a hollow parallelepiped with a stainless steel metallic structure around its perimeter and 304 and 200 mesh stainless steel screens to allow free passage of gases, while providing adequate support for the solid material. In addition, the modules have a temperature sensor and a piping for water vapor and CO2 outlet during regeneration in the central upper part.

[0057] Inside the modules, a solid material suitable for the desired purpose is placed. In this case, desiccant for water removal, and adsorbent for selective CO2 removal. Additionally, the internal part of the module has a resistance arrangement distributed around the solids and another arrangement in the central part. The resistance cartridges have a nominal power between 200-1100 W, as shown in the embodiment represented in Figure 3 (7) . Furthermore, type J temperature sensors are preferably presented inside each module in a central position (8) .

[0058] Particularly for DAC applications in indoor environments (Figure 2a) , the device is characterized by having a sterilization step (2) of the air. This process is fundamental to ensure air quality for people confined to these environments. In one embodiment, it comprises the action of ultraviolet (UV-C) light, used to prevent the reproduction of microorganisms such as viruses, fungi, and bacteria (Figure 2a, (2) ) .

[0059] In said embodiment, the inlet and outlet chambers are made of stainless steel. The inlet chamber is positioned betweenthe inlet (1) and the module (3) , and the outlet chamber is between the module (4) and the outlet (6) . At the ends of the chambers, fan arrangements are coupled, and commercial CO2 sensors are internally positioned to monitor the gas concentration in the gas mixture. In addition, valves, preferably ball valves, are installed at the inlet (1) and outlet (6) of the device.

[0060] Commercial CO2 sensors are housed in the inlet and outlet chambers, and are non-dispersive infrared (NDIR) gas sensors capable of detecting CO2 concentrations in the range of 0-5000 ppm in DAC applications, and detecting 0-60% CO2 in combustion gas mixture applications.

[0061] In one embodiment, coupled to the CO2 capture device (9) there is a storage system, composed sequentially by a condenser (10) , a compressor (11) , and a storage module (13) (Figure 4) . The storage module (cylinder) connects to the capture device via the water vapor and CO2 outlet piping. The cylinder has a hydraulic capacity ranging from 2 to 50 L and a pressure of 60 bar, while the compressor operates up to 60 bar.

[0062] In one embodiment, the present invention also presents a CO2 capture and utilization device in column arrangements, essentially divided into four distinct units (Figure 5) : the arrangement of gas pre-treatment columns represented by columns (14) , (15) , and (16) ; the desiccant module represented by column (17) ; the CO2 capture module, represented by column (18) ; and the CO2 utilization module, represented by column (19) , as shown in Figures 5, 6, and 7.

[0063] In one embodiment, the pre-treatment module is preferably composed of an arrangement of three stainless steel columns (14) , (15) , and (16) , is connected to the desiccant (17) and CO2 capture (18) modules, being activated for the pre-treatment of the gas mixture when the application is CO2 capture from industrial process gas mixtures.

[0064] The column (14) of the pre-treatment module is internally filled with HEPA (High Efficiency Particulate Air) filters, activated carbon filters, ceramic, metal, or fiberglass filters for particulate matter removal. In column (14) , the gas mixture feed source is from the lower end, and the upper end is coupled to the urea mixing and decomposition line, a 1 / 4" stainless steel pipe connecting to column (15) .

[0065] The column (15) of the pre-treatment module has the same dimensions as column (14) and contains the selective catalytic reduction (SCR) catalyst for NOX, composed of noble metals, such as vanadium and platinum, supported on ceramic material. The SCR catalyst is responsible for facilitating the reaction between the reducing agent, usually urea or ammonia, and the nitrous oxides from the industrial process gas mixture. The urea mixing and decomposition line, which connects column (14) and column (15) , is kept heated by an external resistance and continuously receives urea through a spray nozzle. Inside the line, urea decomposition and mixing with the gases to be admitted to column (15) occur from the lower end.

[0066] Coupled to column (15) there is an oven (20) which is responsible for heating the system to the optimal reduction temperature (180 - 250 °C) . At the top of the column, the gas mixture being pre-treated is heated and needs to be cooled. To this end, to take advantage of energy, this stream is admitted into the coils of the desiccant (17) and CO2 capture (18) columns when they are operating in regeneration mode.

[0067] Column (16) of the pre-treatment module also has the same dimensions as column (14) and contains an alkaline solution, such as lime (CaO) or sodium hydroxide (NaOH) solution, which reacts with the SOx in the gas mixture to form sulfites and sulfates. Column (16) receives the SOx-containing gas mixture from the lower end from the outlet of the copper coils in the lower part of the desiccant and CO2 capture modules, in regeneration mode. The pre-treated gas, which exits the upper end of column(16) , is admitted into the desiccant modules (17) through the flow pipes and valves at the lower end of the columns.

[0068] The columns of the desiccant modules (17) , CO2 capture (18) , and mineralization (19) are column arrangements made of a set of tubes manufactured from random copolymer polypropylene (PPR) .

[0069] In one embodiment, the desiccant module (17) comprises two or more PPR tubes internally filled with solid desiccants such as molecular sieves, silicas, and zeolites for removing water from the gas mixture. The capture module (18) comprises two or more tubes, internally filled with solid adsorbents selective to CO2. Before entering the capture module, it is necessary to remove moisture from the gas mixture. For this process, the columns of the desiccant module are arranged in series in relation to the columns of the CO2 capture module, that is, columns (17) contain desiccant material and receive pre-treated gas mixture.

[0070] In the embodiment of the device with two desiccant columns and two CO2 capture columns, they can operate in the following ways: (a) one desiccant column and one CO2 capture column operate in series (Figure 6(a) ) , while the other pair remains in standby or regeneration mode. (b) In another operating arrangement, the two desiccant columns and the two CO2 capture columns operate concomitantly in parallel (Figure 6(b) ) , where each set of modules receives the gas mixture from different or identical feed lines of the gas mixture.

[0071] At the ends of the columns, there are threaded polyamide caps containing flow valves to allow the passage of gases during separation and the closure of the columns during regeneration. While the columns operate in capture mode, the inlet and outlet valves remain open, whereas in regeneration mode, the valves are closed, and the modules are heated to release the CO2 retained in the solid adsorbent and water vapor from the desiccants.

[0072] In the inlet and outlet piping of the desiccant and CO2 capture modules, chambers are installed with commercial non- dispersive infrared (NDIR) CO2 sensors capable of detecting CO2 concentrations in the range of 0-5000 ppm for DAC applications, and detecting 0-60% CO2 for combustion gas mixture applications.

[0073] Furthermore, for regeneration to occur, there is a coil made of a 1 / 4" copper tube running along the entire internal part of the columns. The inlet and outlet of the coil are at the lower end cap of the column. During regeneration, the copper tube is fed with heated water from a thermostatic bath or can connect to the transfer line of the heated gas mixture coming from column (15) or another heated fluid from an industrial process stream.

[0074] In DAC applications, the presence of a fan is necessary to conduct air into the columns (Figure 7) . The fan must be coupled to the lower inlet of the desiccant column (17) , and must have a minimum flow rate of 100 mL.min-1. The fan has a polyamide lid containing 1 / 2" valves and connects to the lower lid of column (17) through a piping. Additionally, in this configuration, electrical resistance capable of reaching an internal temperature of 80-100 °C in the column is also applied for the regeneration process .

[0075] The utilization module (13) , as shown in Figure 4, comprising a column manufactured from DPR (19) , is internally filled with alkaline metal oxides or hydroxides or alkaline earth metal hydroxides for the mineralization of captured CO2 (Figure 6) . The column has the same dimensions as the adsorption columns, however, it does not have the regeneration components.

[0076] As presented for the box arrangement, in the column arrangement there is also a CO2 utilization system connected to the capture system, which is formed by a condenser (10) , a compressor (11) , and a storage module (13) (Figure 4) . The storage module, comprising cylinders, is connected to the capture device via the CO2 piping, which is recovered during the regeneration step. The cylinder has a hydraulic capacity ranging from 2 to 50L and a pressure of 60 bar, while the compressor operates up to 60 bar. This cylinder is connected at the other end to the mineralization column.

[0077] In one embodiment, the present invention also comprises modular equipment for CO2 capture, in a box format (Figure 8) , consisting of an external structure preferably made of galvanized carbon steel or stainless steel, and internally composed of an adsorbent medium (21) and electrical terminals for thermal regeneration and / or pressure swing. Type J thermocouple temperature sensors are strategically positioned inside the module, enabling real-time thermal control.

[0078] In one embodiment, the equipment has a geometry preferably composed of a prismatic central section (21) and truncal-pyramidal ends (22) , presenting gas inlet and outlet at opposite ends of the body (22) (Figure 8) . The gas flow is continuous and transversal to the hood inlet, and each capture module can be operated independently or in conjunction with other interconnected units.

[0079] In one embodiment, the internal functional adsorbent module is constructed with removable modular elements, in the form of cubic cartridges, blocks, or boxes (typical dimensions of 1,000 x 813 x 1,000 mm) , preferable with a stainless steel metallic structure and lateral metallic screen cladding (23) , allowing the passage of gases and adequate support for the adsorbent and / or desiccants materials.

[0080] Inside these cartridges (21) are inserted solid adsorbent materials selective for CO2, such as functionalized activated carbon, zeolites, supported amines, or biopolymerderived composites. The same module can be adapted to contain desiccants (silicas, molecular sieves) for moisture removal, according to the needs of the gas stream.

[0081] The ends of the equipment are equipped with inlet and outlet chambers (22) , preferably made of stainless steel, wherecentrifugal fans for flow induction and control valves, for example, ball valves, are installed. Safety valves and sensors are also positioned in these chambers, allowing CO2 detection in ranges of 0-5000 ppm (DAC environments) or 0-60% (industrial gases) , ensuring continuous monitoring of system efficiency.

[0082] In all CO2 capture and utilization devices, whether in box or column formats, a control and monitoring panel is provided. This panel features two on / off buttons to independently activate the two fan arrangements and two variable speed switches for independent control of fan flow in DAC applications.

[0083] The fan arrangements at the inlet and outlet of both box and column systems use fans with a maximum flow rate of 1000 m3.tr and operate in different modes in the capture device: (a) the two inlet and outlet arrangements operating concomitantly at the same speed; (b) only one of the inlet or outlet fan arrangements operating; and (c) the inlet and outlet fan arrangements operating at maximum speed. Operating modes (a) and (b) are optimized according to the gas mixture composition, adsorbent solid characteristics, and processed air volume. Operating mode (c) is applied for cooling and conditioning the system post-regeneration.

[0084] In one embodiment, still in the device, there is a temperature control and monitoring system with an on / off button and digital temperature indicators and controllers connected to type J temperature sensors and electrical resistances, which are distributed internally for each desiccant and CO2 capture module. The components of the control and monitoring panel are mounted in a box, and a bivolt outlet powers the entire system.

[0085] In CO2 capture mode, the fans and temperature indicators are activated by the on / off buttons identified on the control and monitoring panel. In addition, in capture mode, the ball valves are opened manually or automatically to allow the flow of the gas mixture .

[0086] In one embodiment, still in the capture device, the CO2 sensors installed at the inlet and outlet are switched on independently via an on / off button. Before starting the process, these sensors are calibrated and programmed for continuous monitoring of CO2 quantity at the inlet and outlet of the device. The CO2 quantity data monitored in the inlet and outlet chambers are recorded in tables and graphs and transferred in PDF, Excel, or TXT format to a computer via USB cable, or via Bluetooth.

[0087] In one embodiment, in regeneration mode, the fans and CO2 sensors are turned off using on / off buttons. The temperature indicators remain on, and the controllers are activated and programmed for an operating range of 60-100 °C. Before starting the regeneration process, the ball valves are manually or automatically closed to seal the device.

[0088] In one embodiment, in the storage module, when the regeneration system reaches the programmed temperature, the compressor is activated by an on / off button on the equipment itself, and the valve at the end of the storage module connected to the transfer line is opened. When the pressure drops below 0.2 bar at the compressor inlet, the storage device valve is closed, and the compressor is turned off.

[0089] To restore the system to capture mode, all temperature controllers are turned off, and the fans in operating mode (c) are activated to cool the system by suctioning atmospheric air itself until the ambient temperature is reached.

[0090] In one aspect, the device can be installed both indoors and outdoors, fixed to the floor, wall, or benches, and even in central air conditioning systems and exhaust systems. The device is powered by electricity through one or more outlets in a bivolt configuration. Additionally, in some embodiments, the box-type capture device requires a minimum space of 1 m2for every 1 ton of CO2 captured per year, while the column device requires a minimum of 5 m2for every 1 ton of CO2 captured per year, and the storage or reuse module requires a minimum area of 4 m2.

[0091] The number of modules needed and the size of the devices are adjustable according to the characteristics of the gas mixture fed to the system and the retention capacities of the desiccant and CO2 adsorbent.

[0092] In one embodiment of the present invention, a CO2 capture device in box mode is highlighted. The steps described below are common for atmospheric air, DAC, indoor, and outdoor applications. In the case of indoor environments, air sterilization with UV-C lamps is typically performed beforehand.

[0093] In one embodiment, after entering the device, the gas mixture undergoes a dehumidification process. This process occurs through the action of molecular sieves arranged in a module called a desiccant (3) . The number of modules needed is adjustable according to the moisture characteristics of the gas mixture fed to the system and the water retention capacities of the desiccant.

[0094] After passing through the desiccant module, the gas stream, with a moisture content in the range of 0 - 10%, proceeds to the capture module (4) . The solid adsorbent materials are housed in the capture modules (4) in such a way that they are packed or held in hollow structures, called monoliths, or in pellet configuration, aerogels, or supported on polymeric membranes.

[0095] The saturation of the solid materials contained in the modules detailed in Figure 3 is verified by sensors, specified previously, which measure the CO2 and water vapor content in the inlet and outlet streams of the device. Periodically, the CO2 and H2O content in the outlet stream equals that of the inlet, indicating the saturation of the materials, or reaches CO2 concentration levels up to the maximum desirable limit for the application .

[0096] In this scenario, regeneration of desiccant and adsorbent materials becomes necessary. In order to regenerate these materials and recover water and CO2, Temperature-SwingAdsorption (TSA) and Pressure-Swing Adsorption (PSA) processes are performed for module regeneration and H2O and CO2 recovery.

[0097] In one embodiment, TSA and PSA processes occur within a temperature range of 60 °C to 100 °C and at pressures below 500 mmHg, respectively. For regeneration, the solids are heated by resistance cartridges controlled up to a temperature of 60 °C or up to 100 °C (7) . After heating for approximately 0.5 h, a compressor is used to reduce the pressure below 0.2 bar in the capture columns, so that by pressure difference CO2 is transferred from the CO2 capture box to the storage module.

[0098] In one embodiment, during the regeneration operation, the device operates in a closed system, which is ensured through valves installed at the inlet (1) and outlet (6) of the device (Figure 2) , properly sealed during this operation. The pressure of the box system is monitored to observe when it is necessary to transfer the gas containing CO2 and H2O from the box to the water removal and CO2 storage unit. It is highlighted that, during the regeneration process in an indoor environment, the sterilization unit is thermally isolated from the modules to avoid loss of UV-C light activity.

[0099] In one embodiment, the CO2 and H2O mixture is directed to the condensing unit for H2O separation (10) , as shown in Figure 4, and the CO2 is directed to the storage unit (13) through the opening of a pressure control valve (12) with the aid of a compressor (11) . Coupled to the storage module, a pressure indicator and controller must be inserted, showing when the pressure inside the module reaches the maximum pressure of 60 bar. When the limit of 60 bar is reached, it is necessary to change the storage module manually. In addition to the sensor, a safety and relief valve is also installed, operating as a safeguard in cases of overpressure.

[0100] In one embodiment of the invention, multiple units of the box device can be used to increase the overall sorption capacity of the process. Furthermore, for the process to beconducted in a continuous regime, the devices must operate in cycles, utilizing at least two devices. Thus, while one device undergoes gas adsorption, the other undergoes the regeneration of solid materials, resulting in the release of retained carbon dioxide and water vapor.

[0101] In one embodiment, after gas storage, the pressure control valve (12) is manually or automatically closed, the modules are cooled to ambient temperature by insufflating external air, with the inlet and outlet of the capture module open, thus enabling a new cycle. The CO2 can be used directly or converted for subsequent use in industrial sectors such as agribusiness, civil construction, pharmaceuticals, or as a raw material in the production of synthetic fuels.

[0102] In one embodiment of the invention, a CO2 capture system is also highlighted, particularly for applications involving gas mixtures from industrial processes, such as combustion gas and biogas streams (Figure 5) . In this context, the embodiment of the invention presents dynamic operation between adsorption columns with channels for energy integration and a mineralization column.

[0103] In one embodiment of the invention, particularly for industrial process mixtures containing CO2 in the range of 8 - 60% (w w-1) , in the column device, the gas mixture undergoes a pretreatment (Figure 5) for particulate matter removal in column (14) and acid gas NOx and SOx removal in columns (15) and (16) , respectively .

[0104] The industrial process gas mixture first enters column (14) , which contains HEPA filters, activated carbon filters, or a combination of both, for the retention of particulate matter between 2.5 and 10 micrometers.

[0105] After particulate matter removal, the gas mixture stream needs to be heated to 100 - 180 °C and mixed with ammonia vapor for NOx removal. This process occurs in the urea mixing and decomposition line with heat recovery from the industrial processitself, or from an additional heat source. The NOx removal reaction involves injecting a reducing agent, such as ammonia (NH3) or urea, into the gas mixture stream containing nitrogen oxides.

[0106] The gas mixture containing the reducing agent enters column (15) for NOx removal (denox) in the presence of a selective catalytic reduction (SCR) catalyst, composed of noble metals, such as vanadium and platinum, supported on ceramic material. The reaction occurs in the temperature range from 180 to 250°C, in which nitrogen oxides react with the reducing agent to form nitrogen (N2) and water (H2O) :4NO(g) + 4NH3(V) + O2(g) 4N2(g) + 6H2O(v)

[0107] In one embodiment, there is the possibility for the heated gas mixture stream exiting column (15) to first pass through the hot fluid pipes of the column that is in standby mode, transferring heat to the regeneration process (Figure 5) . Or the pre-treated and heated stream can be cooled in a heat exchanger. Subsequently, the cooled stream passes through an SOx removal bed, column (1 ) .

[0108] In one embodiment, SOx removal (desox) involves contacting the gas mixture with an alkaline solution, such as lime (CaO) or sodium hydroxide (NaOH) solution, which reacts with the SOx in the gas mixture to form sulfites and sulfates. The reaction occurs at the interface between the gas mixture and the alkaline solution, simplified as follows:

[0109] Subsequently, the sulfite can be oxidized to sulfate by oxygen or other oxidizing agents.SO32”(aq) + 202(g) SO42“(aq)

[0110] In one embodiment, the pre-treated mixture enters the CO2 capture device, passing through the columns in series that are operating to remove water vapor (desiccant) and CO2 (adsorbent) . Periodically, the CO2 content in the outlet stream reaches maximumvalues for the process, indicating the saturation of the materials. The saturation of the adsorbents contained in the columns is verified by sensors that measure the gas composition at the inlet and outlet, especially the CO2 concentration at the outlet of the adsorbent column.

[0111] In one embodiment, in order to regenerate the desiccant and adsorbent materials, TSA and PSA processes are combined for module regeneration and CO2 recovery. TSA and PSA processes occur at a temperature range of 60°C - 100°C, and pressure below 0.2 bar .

[0112] In one embodiment, particularly during regeneration, there are internal pipes within the columns containing heated fluid that are in contact with the solids to be regenerated. The regeneration process of the materials in the columns lasts approximately 0.5 h. The columns are cooled by passing fluid through internal pipes that are in contact with the adsorbent solids or by air flow from the environment itself using fan arrangements. From then on, the column is ready for a new adsorption cycle.

[0113] In one embodiment, during the regeneration step, the column in standby mode operates in a closed system through valves installed at the inlet and outlet of the column, which are properly sealed during this operation. The compressor acts on the storage cylinder, reducing the internal pressure of the columns to values less than 0.2 bar.

[0114] Furthermore, in one embodiment, it is possible to operate two or more desiccant and adsorbent modules simultaneously, ensuring that CO2 capture remains continuous. In this case, while the saturated columns are undergoing the regeneration process and then entering standby mode, other columns are operating in CO2 capture mode.

[0115] In addition to the parallel operation of the columns, i.e., one column operating in adsorption and another inregeneration or standby, in one embodiment, it is possible for the columns to operate in a series arrangement (Figure 6a) . In the case of series operation, the first adsorbent column (18) is fed with the process gas and the second adsorbent column (18) is fed with the outlet stream of the first adsorbent column.

[0116] After the capture and storage process, in one embodiment, the CO2 is directed to utilization, which involves mineralization through columns filled with alkaline metal oxides or alkaline metal hydroxide solutions. This step is also illustrated in Figure 4. Coupled to the mineralization module, a pressure controller must be placed for control and limitation of carbonate production. When the limit is reached, it is necessary to change the storage column manually.

[0117] In one embodiment, the mineralization system is based on an inorganic salt in an aqueous medium, specifically using calcium chloride (CaC12) solutions as a mineralizing precursor. In this configuration, the CO2 is bubbled into a 0.1 M CaC12 solution, which is previously added to alkalizing agents such as ammonium hydroxide (NH4OH) or monoethanolamine (MEA) , and can be combined with a chitosan membrane or sphere, in order to promote the elevation of the solution's pH and favor the precipitation of high- purity calcium carbonate (CaCCh) . The process occurs in closed reactors or vertical columns under continuous or batch regime, operating at ambient temperature and atmospheric pressure.

[0118] In one embodiment, the invention also contemplates a CO2 capture system with a focus on industrial applications, particularly for treating gases containing between 2% and 20% CO2 (w / w) , such as in combustion streams, forced ventilation, or fermentation processes. The system utilizes modular equipment (Figure 8) that allows for isolated operation or multiple modular capture units, enabling continuous operation in parallel or in series .

[0119] In one embodiment, the gas mixture containing CO2 is admitted into the equipment through one of the ends of the mainbody, with a truncal-pyramidal geometry, and led along the functional module. Internally, there are cartridges or modular blocks containing solid adsorbent materials selective to CO2. The gas passes through the blocks by means of perforated side screens (200 mesh) , promoting efficient contact between the flow and the adsorbent bed.

[0120] In one embodiment, during the capture process, CO2 sensors monitor the gas concentration in the inlet and outlet streams. When the CO2 concentration exceeds the pre-established limit, it indicates the exhaustion of the bed's capacity, characterizing the saturation of the adsorbent.

[0121] In one embodiment, to ensure continuous operation, the system includes a second identical module (or set of modules) , allowing one module (or set of modules) to operate in capture while the other is in regeneration or standby mode. The arrangement can also operate with modules arranged in series, increasing capture efficiency.

[0122] In one embodiment, regeneration of the beds can be performed by three distinct modes: by pressure swing (PSA) , by temperature swing (TSA) , or by a combination of both. In PSA mode, control valves reduce the internal pressure of the system below 0.2 bar, facilitating the desorption of retained CO2. In TSA mode, electrical resistances from 200 to 1100 W raise the bed temperature to ranges between 60 and 100 °C, promoting the release of CO2 by breaking physical-chemical interactions.

[0123] In one embodiment, in combined regeneration (TSA-PSA) , both mechanisms occur simultaneously, reducing desorption time and increasing process efficiency. The regenerated CO2 is conducted through the central upper piping and can be directed to a compressed and pressurized storage system.

[0124] The average regeneration time for the bed varies between 30 and 60 minutes, depending on the operating conditions and the type of solid material used. In one embodiment, after regeneration,the system is cooled by forced air flow or by activating internal coils containing a cooling fluid.

[0125] In one embodiment, during regeneration, inlet and outlet valves remain closed, ensuring module sealing. The regeneration flow is maintained in a closed circuit, with control by temperature and pressure sensors. The structural materials of the modules are stainless steel or galvanized steel, with screens and seals resistant to temperatures of up to 200 °C and pressures of up to 5 bar, ensuring system integrity under various operating conditions .

[0126] The modular geometry embodiment allows more than two pieces of equipment to be connected in series or parallel, optimizing the process scale. Additionally, the system can be adapted for integration with mineralization lines, where the desorbed CO2 is directed to reactors containing alkaline metal oxides or alkaline solutions, aiming to convert it into stable carbonates .Examples of Embodiment of the Invention

[0127] The examples described below are used for illustration purposes only and do not limit the mode of execution. Depending on the necessary conditions, other operational parameters may be applied, and different results may be obtained.

[0128] Example 1: In one embodiment of the present invention, adsorbents derived from chitosan and cellulose with high specific area in the range of 600-1100 m2.g-1, nitrogen content in the range of 1-8% are applied as adsorbents in pellet or powder form, in a packed bed column configuration, for direct air capture processes or industrial gas mixtures. In the system, the adsorbents are surrounded by pipes containing water for heating and cooling during the regeneration process.

[0129] This embodiment particularly involves the application of a gas mixture with a composition of 0.1% CO2, 78.9% N2, and 21% O2 that enters the system at an operational inlet and outlet flowrate of 0.04 and 0.03 nd.tr1, respectively, and can enter the system at a maximum flow rate of 10 nd.tr1. Flow rates greater than 10 nd.tr1do not result in efficient CO2 separation, as the residence time of the gas mixture in the column drastically decreases.

[0130] Particularly, in one embodiment of the invention, for direct air capture in both indoor and outdoor environments, materials containing primary amine functional groups, which can be derived from chitosan or other organic compounds, are indicated. For some embodiments, adsorbents or mixtures of adsorbents derived from chitosan were specifically applied, which were synthesized by the methods described below:

[0131] In the first method, chitosan undergoes hydrothermal treatment, where a mixture of chitosan and water in a 1:10 mass ratio is placed in an autoclave reactor. The mixture is then heated to 180 °C under autogenous pressure (approximately 2 bar) for 48 hours. After the reaction, the autoclave was immediately cooled with water and the content was filtered. The solid product was collected, washed until pH~7, and dried at 110°C for 2 hours. The resulting solid material was named HTCQ. The obtained hydrochar has a specific surface area of 2 m2.g-1, basicity of 2.4 mmol.g-1(Boehm titration) , and adsorption capacity of 0.45 mmol.g-1at 25°C and 1 bar (Figure 8) .

[0132] In the second method, chitosan or chitosan hydrochar is impregnated with a 1:1 mass ratio of K2CO3 : chitosan . For every 3 g of K2CO3, 10 mL of deionized water was used to prepare the solution. The mixture was dried in an oven at 110°C for 24 h. The impregnated sample was transferred to a stainless steel tubular reactor and, under N2 flow at 100 mL.min-1, was heated from 25 to 300°C (8°C.min~ !) and maintained at this temperature for 30 minutes. Then, under the same N2 conditions, the material was activated at a temperature of 700°C at a heating rate of 10°C.min~1, and held at the final temperature for 60 minutes. After cooling the system, the solid was removed from the reactor and washed with hot water until the solution was neutral to remove inorganic compounds.

[0133] Finally, the solid was dried in an oven at 110°C for 4 h. The obtained porous biochar have a specific surface area in the range of 600 - 2000 m2.g-1, chemical composition 50 - 65% C, 3 - 4% H, 2 - 8% N and 30 - 44% 0, basicity of 0.9 mmol g-1(Boehm titration) and adsorption capacity in the range of 4.5 - 5.5 mmol g-1at 25°C and 1 bar (Figure 9) . By this method, activated chitosan biochar (CAQ700) and hydrochar (CAHTCQ700) were obtained.

[0134] In the third method, a pelletized biochar derived from cellulose was added to the mixture of chitosan and K2CO3 solution prepared with 2% acetic acid. The mass ratio follows a 20:1:1:15 ratio of biochar : chitosan : K2CO3 : 2% acetic acid, respectively. The mixture with pelletized biochar was dried in an oven at 110°C for 24 h. Subsequently, the material was subjected to the same treatment steps as those described in the second method above. By this method, impregnated pelletized biochar (CIP) was obtained. The obtained porous biochar has a specific surface area in the range of 850-1000 m2.g-1, basicity of 1.3 mmol.g-1(Boehm titration) and adsorption capacity of 1.8 mmol.g-1at 25 °C and 1 bar (Figure 10) .

[0135] In the fourth method, a solution of chitosan at a concentration of 2% (w.v-1) in 2% (v.v-1) acetic acid and CAQ700 was prepared in a mass ratio of 1:2 ( chitosan : chacoal ) . The mixture was maintained in an ultrasonic bath for 30 minutes and then heated at 60°C for 2 hours. Subsequently, the mixture was cooled in a thermostatic bath regulated to 10°C. The mixture was neutralized with 0.1 mol In1NaOH solution, filtered and washed until pH 7. The solid product was dried at 70°C in a stove. The biochar was impregnated with chitosan solubilized in acetic acid for 24, 48 and 120 h. In this method, the effect of polymer solubilization time was evaluated. The obtained biochar has a specific surface area in the range of 400 to 600 m2.g-1, basicity of 1-3 mmol.g-1(Boehm titration) , and adsorption capacity in the range of 0.25 - 3 mmol.g-1at 25°C and 1 bar (Figure 11) . The impregnated biocharswere named CHIT-CAQ700-t , where "t" is the solubilization time of chitosan in 2% acetic acid.

[0136] For the evaluation of these materials, CO2 adsorptiondesorption tests were conducted using a thermogravimetric analyzer (TGA) . 5-12 mg of sample was weighed in a platinum crucible and, subsequently, the sample was subjected to heating at a rate of 10°C min-1from ambient temperature to 180°C, under a flow of 50 mL min-1of N2, remaining heated for 1 hour. Then, the treated sample was saturated with pure CO2 under a flow of 50 mL min-1at 25°C.

[0137] In the fifth method, a chitosan solution at a concentration of 5% - 20% (w.v-1) in 2% (v.v-1) acetic acid was prepared, aiming to achieve between 5% - 20% (w.w-1) of chitosan in biochar. Chitosan solubilization in acid solution occurs under continuous mechanical stirring for 6h and then subjected to an ultrasonic bath for 20 minutes. Subsequently, the chitosan solution was mixed with the dry pelletized biochar in a flat- bottomed container, and the mixture was left to rest for 12 hours at ambient temperature, thereby characterizing the impregnation.

[0138] After the impregnation period, the mixture was neutralized with an aqueous solution of 0.5 mol.L-1NaOH in a volume equal to that of the acid used in the chitosan solubilization process. The excess solution was removed by gravity filtration. The resulting impregnated material was then dried in a stove at a temperature between 100 °C and 150 °C for a sufficient time to obtain a material with a humidity of less than 5%.

[0139] The dried material was subjected to pyrolysis at temperatures between 280°C - 600°C for 1 hour, under a continuous argon flow of 2 L.min-1for every 1 kg of solid material. The obtained material presented a porous structure characteristic of pelletized biochar, in addition to functionalization with nitrogenous groups derived from the thermal decomposition of chitosan .

[0140] These impregnated biochars were designated as XCHIT-CIP- T, where "X" represents the chitosan content and "T" denotes the pyrolysis temperature.

[0141] The biochars obtained by this method had a specific surface area in the range of 919 to 1084 m2.g-1and CO2 adsorption capacity in the range of 1.3 to 1.8 mmol.g-1, under conditions of 25°C and 1 bar. For characterization, the material was applied as an adsorbent phase in a fixed-bed column system, with the outlet coupled to a mass spectrometer. The gas mixture used for evaluation contained a synthetic mixture containing 0.1% CO2, 20.9% O2 and 79% N2. The system was operated with 1 g of adsorbent at a constant volumetric flow rate, achieving 100% CO2 removal efficiency during the adsorption period and a saturation time of up to 1 hour. The system's performance curve is represented in Figure 12.

[0142] For the evaluation of the CO2 separation process, the first column was filled with 95% GIF and 5% CAQ, and the second column with 100% CAQ.

[0143] In the column system embodiment, CO2 sensors were coupled to the inlet and outlet. In Figure 13, it is verified that 100% of the CO2 was removed from the feed mixture, in the interval of 0 - 5 h. During this time, the CO2 content at the outlet remains around 400 ppm, the average CO2 concentration in the atmosphere, or even below 400 ppm.

[0144] When the outlet concentration is 400 ppm above the inlet CO2 concentration (1000 ppm) , it is known that the saturation time has been reached, and the desorption process is necessary to regenerate the material. Particularly under the conditions and configurations of the process in Example 1, the saturation time is 7 hours .

[0145] In this embodiment of the present invention, the regeneration step of the adsorbents in the columns is carried out by increasing the temperature through the passage of hot water, but it is not limited to hot water. In the process, particularly,the CO2 desorption is carried out under vacuum in the range of 200 - 500 mbar and at a temperature in the range of 50 - 70 °C.

[0146] The desorbed CO2 was directed to mineralization in a third column (18) containing 1 kg of calcium oxide.

[0147] Example 2: In another embodiment of the present invention, commercial cellulose-derived adsorbents with an adsorption capacity of 1.6 mmol.g-1, in pellet form, are applied to evaluate the CO2 removal process in a box (Figure 2) from a gas mixture in an outdoor or indoor environment. The adsorbents were covered by a metallic structure called capture modules (4) and surrounded by a heating resistance during the regeneration step. Cooling is performed by suctioning the ambient air itself.

[0148] This embodiment particularly involves the application of a gas mixture with a composition of 0.04 - 0.4% CO2, in N2 and O2, which enters the box by suction resulting from the operation of a 4 fans arrangement at the inlet and 4 fans at the outlet.

[0149] For the CO2 separation process, the first module (3) was filled with a molecular sieve for water removal. The three subsequent modules (4) were filled with the adsorbent, specifically commercial activated carbon.

[0150] To evaluate the system, CO2 sensors were coupled to the inlet and outlet of the box. From Figure 14, it can be seen that up to 75% of the CO2 was removed from the feed mixture, in the interval of 0 - 1 h using commercial cellulose-derived adsorbent. It is worth noting that other adsorbent materials can be used to increase the CO2 removal efficiency.

[0151] When the outlet concentration is equal to the inlet concentration, it is known that the saturation time has been reached, and the desorption process is necessary to regenerate the material. Particularly under the process conditions and configurations, the saturation time exceeds 7 hours.

[0152] The regeneration step of the adsorbents in the columns is carried out by increasing the temperature using resistance oranother heat source. In the process, particularly, the CO2 desorption is carried out at a temperature in the range of 80 - 100 °C.

[0153] The desorbed CO2 is directed to a storage unit, particularly a gas cylinder.

[0154] Example 3: In another embodiment of the present invention, carbon dioxide (CO2) mineralization tests were conducted in a 0.1 M calcium chloride (CaC12) aqueous solution, aiming at the formation of calcium carbonate (CaCCh) under continuous gaseous CO2 flow in an open reactor.

[0155] The system containing captured CO2 was coupled to 250 mL recipients containing 100 mL of CaC12 solution and different combinations of additives, including monoethanolamine (MEA) , ammonium hydroxide (NH4OH) and chitosan membrane. The formed precipitate was separated by filtration, dried in a stove and weighed for yield calculation.

[0156] The addition of 0.4 M NH4OH resulted in an average yield of 18%. With 10 mL of virgin MEA, the achieved yield was 66%. The use of 1 M NH4OH alone generated an average yield of 80%. The combination of 10 mL of 1 M NH4OH with 10 mL of virgin MEA resulted in a yield of 91%.

[0157] The application of isolated chitosan membrane did not result in precipitate formation (0% yield) . When combined with NH4OH or MEA, yields ranged from 35% to 86%. The combination of chitosan membrane with both additives (1 M NH4OH and virgin MEA) showed an average yield of 86%. The control (without additives) did not form precipitate.

[0158] The data demonstrate that the combined use of MEA and NH4OH in an aqueous CaC12 medium promotes the efficient formation of calcium carbonate, configuring a mineralization route applicable to the fixation of captured CO2. Figure 15 presents a comparison of the yields obtained under the different evaluated conditions .

[0159] Infrared spectroscopy (IR) confirmed the chemical identity of calcium carbonate, with characteristic vibrational bands of the carbonate ion (CO32-) , including an intense asymmetric stretching near 1410 cur1, symmetric stretching around 1060 cur1, and out-of-plane bending in the region of 870 cur1.

[0160] The calcium carbonates presented purity superior to 99.9% by mass and were compatible with analytical grade calcium carbonate, with characteristic thermal decomposition in the range of 700 to 800°C. Purity was determined based on the mass loss associated with CO2 release (CaCCh decomposition) , confirming the chemical identity of the product as CaCOs with an estimated purity of 100%.

[0161] A device for removing and capturing carbon dioxide (CO2) from direct air capture (DAC) on indoor or outdoor environments, from gas mixture streams, or industrial process gases, the device comprising at least one desiccant module (3, 17) , at least one adsorbent CO2 capture module (s) (4, 18) , at least one storage and / or utilization module (s) (13, 19) , wherein the device can be arranged in box modules or column modules, depending on the use. The device arranged in box modules further comprises: at least one air sterilization module (2) , at least one inlet and one outlet chambers, with the inlet chamber (s) located between the inlet (s)(I) and desiccant module (s) (3) and the outlet chamber (s) located between adsorbent CO2 capture module (s) (4) and the outlet (s) (6) , preferably wherein it also comprises valves (12) , preferable the valves are installed at the inlet (s) (1) and outlet (s) (6) , and the storage system comprising: condenser (s) (10) , compressor ( s )(II) , and a storage or utilization module (13) .

[0162] The device can also be arranged in a modular box format, with an external body preferably composed of a prismatic central section (21) and truncal-pyramidal ends (22) , having gas inlet (s) and outlet (s) at opposite ends of the body (22) , internally containing a functional module with removable modular elements in the form of cartridges, blocks or boxes (23) , wherein said modularelements are filled with adsorbent and / or desiccant materials, or has a thermal and / or pressure swing regeneration system(s) , with the gas flow being continuous and transversal to the lateral faces of the modular elements (23) , wherein, the at least one lateral face of the modular elements (23) is preferably perforated, more preferably is a perforated screen, with the possibility of isolated operation or to connect multiple modular element units. The device further comprises at least one CO2 sensor, at least one temperature sensor, at least one centrifugal fan, and / or at least one control valve. Additionally, the box modules- are arranged in parallel to each other, with resistance arrangements distributed around the solid materials and the presence of temperature sensors inside each module, preferably in a central position.

[0163] The device in box modules arrangement, internally containing two distinct modules: a functional module filled with removable modular elements with adsorbent and / or desiccant medium, and a thermal and / or pressure swing regeneration system module, and the device being further equipped with temperature and CO2 sensors, wherein they are preferably installed in the gas inlet and outlet chambers, together with centrifugal fans and control valves .

[0164] The device arranged in column modules further comprises: gas pre-treatment columns (14, 15 and 16) , preferably wherein the pre-treatment column (s) (14) is a filter column comprising HEPA filters, activated carbon filters, ceramic and / or fiberglass filters; the pre-treatment column (s) (15) is a heatable column comprising a selective catalytic reduction (SCR) catalyst; and the pre-treatment column (s) (16) comprises alkaline solutions. The device further comprises at least one central resistance or coils containing fluid positioned internally to the desiccant module (17) and CO2 capture module (18) ; at least one temperature sensor inside each column, preferably in a central position; at least one fan at the inlet and at least one fan at the outlet of the columns; at least one CO2 sensor; and at least one control valve. Theutilization module (19) is a mineralization module (19) , filled with oxides or hydroxides of alkaline or alkaline earth metals.

[0165] The column modules are arranged in series or parallel; wherein a second identical module or set of modules are arranged in series to increase capture efficiency or are arranged in parallel to operate continuously, allowing one module or set of modules to operate in capture mode while the other is in regeneration or standby mode.

[0166] A process for removing carbon dioxide (CO2) from a gas mixture, particularly from atmospheric air in indoor or outdoor environments, as well as from other emission sources such as industrial process gases, combustion gas, and biogas, by means of a cyclic CO2 separation process using the device of any of claims 1 to 10, wherein the process preferably applying adsorbents materials selective to CO2 in a column or box module systems comprising continuous operation from the following sequential steps: (a) treating the gas mixture by means of sterilization (2) followed by dehumidification (3) using desiccant material particularly when in indoor environment applications; or solely by dehumidification (17) particularly when in outdoor environments in a direct air capture (DAC) process; or combining CO2 adsorption with chemical processes for the removal of other gases (14) , (15) , (16) , and (20) , such as NOx and SOx; (b) contacting the treated gas mixture with the adsorbent material for CO2 removal by flow through the adsorption modules, whether in a column or box module, operating under ambient pressure and temperature conditions; (c) isolating the dehumidification and adsorption system for desiccant regeneration and CO2 desorption; (d) increasing the temperature to values between 60-100°C with injection of heated fluid (air or water) in coils, or other forms of heat transfer through resistance cartridges, magnetic body, or recovered heat from an industrial process; (e) reducing the system pressure to values below 0.2 bar with vacuum pump activation; (f) separating the desorbed CO2 from water vapor by condensation (10) and storing it in storage modules(13) , or, subsequently, being directed to utilization (13) , converting it into inorganic carbonates through mineralization; and (g) reducing the system temperature to ambient conditions by passing ambient air or another cold stream, to initiate a new CO2 adsorption cycle.

[0167] The adsorbent materials derived from chemical activation and hydrothermal treatment of chitin, chitosan, or other biomasses, functionalized with amines or polymeric solution, have a specific surface area in the range of 300 - 2000 m2.g-1, a pore volume in the range of 0.01 - 0.9 cm3.g-1, a pore diameter in the range of 20 - 200 nm, a nitrogen content expressed as mass percentage in the range of 1 - 10%, and a CO2 adsorption capacity in the range of 0.7 - 5.5 mmol.g-1under ambient conditions. The carbon dioxide composition in the gas mixture entering the device system comprises the range of 0.04 to 95%, and the gas mixture flow rate comprises the range of 0.02 to 1000 m3.h-1.

[0168] The process involves inserting at least one air sterilization module using UV-C ultraviolet light, preceding the dehumidification module, particularly in indoor environment applications; inserting gas mixture treatment units for the removal of particulate matter and acidic gases, preceding the dehumidification unit, particularly in combustion gas or biogas applications; inserting at least one dehumidification unit preceding the carbon dioxide capture module ensures that the gas mixture passes through the adsorbent material with a moisture content in the range of 0 - 10%.

[0169] The solid materials are arranged in box modules or adsorption columns such that they are packed or supported in hollow structures, called monoliths, or in a configuration of pellets, aerogels, or supported on polymeric membranes. The outlet stream contains a carbon dioxide concentration in the range of 0.04 - 0.1% in combustion gas or biogas applications, and carbon dioxide in the range of 0.001 - 0.01% in atmospheric air applications.

[0170] The process involves operations in Temperature Swing Adsorption (TSA) and Pressure Swing Adsorption (PSA) , with regeneration temperatures between 80-100 °C and pressures below 0.2 bar, respectively, and an approximate duration of 0.5 hours. The action of resistance cartridges with a nominal power between 200-1100 W or a magnetic body, inserted into the modules for desorption of carbon dioxide and water vapor retained in the modules .

[0171] The process comprises a step of mineralization of the captured carbon dioxide, performed by passing a CO2 gas stream through an aqueous solution of calcium chloride (CaC12) at 0.1 M, previously alkalized with ammonium hydroxide (NH4OH) and / or monoethanolamine (MEA) , combined with a chitosan membrane or sphere, in order to promote the precipitation of high-purity calcium carbonate (CaCCh) ; the process being conducted in reactors or vertical columns, at room temperature and atmospheric pressure, in continuous or batch mode.

Claims

CLAIMS1. A DEVICE for removing and capturing carbon dioxide (CO2) from direct air capture (DAC) on indoor or outdoor environments, from gas mixture streams, or industrial process gases, the device comprising at least one desiccant module (3, 17) , at least one adsorbent CO2 capture module (s) (4, 18) , at least one storage and / or utilization module (s) (13, 19) , wherein the device can be arranged in box modules or column modules, depending on the use.

2. A DEVICE according to claim 1, wherein the device are arranged in box modules and further comprises: at least one air sterilization module (2) , at least one inlet and one outlet chambers, with the inlet chamber (s) located between the inlet (s)(I) and desiccant module (s) (3) and the outlet chamber (s) located between adsorbent CO2 capture module (s) (4) and the outlet (s) (6) , preferably wherein it also comprise valves (12) , preferable the valves are installed at the inlet (s) (1) and outlet (s) (6) , and the storage system comprising: condenser (s) (10) , compressor ( s )(II) , and a storage or utilization module (13) .

3. A DEVICE according to claim 1 or 2, wherein it is arranged in a modular box format, with an external body preferably composed of a prismatic central section (21) and truncal-pyramidal ends (22) , having gas inlet (s) and outlet (s) at opposite ends of the body (22) , internally containing a functional module with removable modular elements in the form of cartridges, blocks or boxes (23) , wherein said modular elements are filled with adsorbent and / or desiccant materials, or has a thermal and / or pressure swing regeneration system(s) , with the gas flow being continuous and transversal to the lateral faces of the modular elements (23) , wherein, the at least one lateral face of the modular elements (23) is preferably perforated, more preferably is a perforated screen, with the possibility of isolated operation or to connect multiple modular element units.

4. A DEVICE according to any of claims 1 to 3, wherein the device further comprises at least one CO2 sensor, at least onetemperature sensor, at least one centrifugal fan, and / or at least one control valve.

5. A DEVICE according to any of claims 1 to 4, wherein the modules are arranged in parallel to each other, with resistance arrangements distributed around the solid materials and the presence of temperature sensors inside each module, preferably in a central position.

6. A DEVICE according to claim 3, wherein it internally containing two distinct modules: a functional module filled with removable modular elements with adsorbent and / or desiccant medium, and a thermal and / or pressure swing regeneration system module, and the device being further equipped with temperature and CO2 sensors, wherein they are preferably installed in the gas inlet and outlet chambers, together with centrifugal fans and control valves .

7. A DEVICE according to claim 1, wherein the device are arranged in column modules and further comprises: gas pretreatment columns (14, 15 and 16) , preferably wherein the pretreatment column (s) (14) is a filter column comprising HEPA filters, activated carbon filters, ceramic and / or fiberglass filters; the pre-treatment column (s) (15) is a heatable column comprising a selective catalytic reduction (SCR) catalyst; and the pre-treatment column (s) (16) comprises alkaline solutions.

8. A DEVICE according to claim 1 or 7, wherein the device further comprises at least one central resistance or coils containing fluid positioned internally to the desiccant module (17) and CO2 capture module (18) ; at least one temperature sensor inside each column, preferably in a central position; at least one fan at the inlet and at least one fan at the outlet of the columns; at least one CO2 sensor; and at least one control valve.

9. A DEVICE according to any of claims 1, 7 or 8, wherein the utilization module (19) is a mineralization module (19) , filled with oxides or hydroxides of alkaline or alkaline earth metals.

10. A DEVICE, according to any of claims 1, 7, 8 or 9, wherein the column modules are arranged in series or parallel;wherein a second identical module or set of modules are arranged in series to increase capture efficiency or are arranged in parallel to operate continuously, allowing one module or set of modules to operate in capture mode while the other is in regeneration or standby mode.

11. A PROCESS for removing carbon dioxide (CO2) from a gas mixture, particularly from atmospheric air in indoor or outdoor environments, as well as from other emission sources such as industrial process gases, combustion gas, and biogas, by means of a cyclic CO2 separation process using the device of any of claims 1 to 10, wherein the process preferably applying adsorbents materials selective to CO2 in a column or box module systems comprising continuous operation from the following sequential steps :(a) treating the gas mixture by means of sterilization (2) followed by dehumidification (3) using desiccant material particularly when in indoor environment applications; or solely by dehumidification (17) particularly when in outdoor environments in a direct air capture (DAC) process; or combining CO2 adsorption with chemical processes for the removal of other gases (14) , (15) , (16) , and (20) , such as NOx and SOx;(b) contacting the treated gas mixture with the adsorbent material for CO2 removal by flow through the adsorption modules, whether in a column or box module, operating under ambient pressure and temperature conditions;(c) isolating the dehumidification and adsorption system for desiccant regeneration and CO2 desorption;(d) increasing the temperature to values between 60-100°C with injection of heated fluid (air or water) in coils, or other forms of heat transfer through resistance cartridges, magnetic body, or recovered heat from an industrial process;(e) reducing the system pressure to values below 0.2 bar with vacuum pump activation;(f) separating the desorbed CO2 from water vapor by condensation (10) and storing it in storage modules (13) , or,subsequently, being directed to utilization (13) , converting it into inorganic carbonates through mineralization; and(g) reducing the system temperature to ambient conditions by passing ambient air or another cold stream, to initiate a new CO2 adsorption cycle.

12. A PROCESS according to claim 11, wherein the adsorbent materials derived from chemical activation and hydrothermal treatment of chitin, chitosan, or other biomasses, functionalized with amines or polymeric solution, have a specific surface area in the range of 300 - 2000 m2.g-1, a pore volume in the range of 0.01 - 0.9 cm3.g-1, a pore diameter in the range of 20 - 200 nm, a nitrogen content expressed as mass percentage in the range of 1 - 10%, and a CO2 adsorption capacity in the range of 0.7 - 5.5 mmol.g~1under ambient conditions.

13. A PROCESS according to claim 11, wherein the carbon dioxide composition in the gas mixture entering the device system comprises the range of 0.04 to 95%, and the gas mixture flow rate comprises the range of 0.02 to 1000 nd.tc1.

14. A PROCESS according to claim 11, wherein inserting at least one air sterilization module by UV-C ultraviolet light preceding the dehumidification module, particularly in indoor environment applications.

15. A PROCESS according to claim 11, wherein inserting gas mixture treatment units for the removal of particulate matter and acidic gases, preceding the dehumidification unit, particularly in combustion gas or biogas applications.

16. A PROCESS according to claim 11, wherein inserting at least one dehumidification unit preceding the carbon dioxide capture module ensures that the gas mixture passes through the adsorbent material with a moisture content in the range of 0 - 10% .

17. A PROCESS according to claim 11, wherein the solid materials are arranged in box modules or adsorption columns such that they are packed or supported in hollow structures, calledmonoliths, or in a configuration of pellets, aerogels, or supported on polymeric membranes.

18. A PROCESS according to claim 11, wherein the outlet stream contains a carbon dioxide concentration in the range of 0.04 - 0.1% in combustion gas or biogas applications, and carbon dioxide in the range of 0.001 - 0.01% in atmospheric air applications .

19. A PROCESS according to claim 11, wherein the operation is in Temperature Swing Adsorption (TSA) and Pressure Swing Adsorption (PSA) , with a regeneration temperature between 80-100 °C and pressure below 0.2 bar, respectively, with an approximate duration of 0.5 h.

20. A PROCESS according to claim 11, wherein the action of resistance cartridges with a nominal power between 200-1100 W or a magnetic body, inserted into the modules for desorption of carbon dioxide and water vapor retained in the modules.

21. A PROCESS according to any of claims 11 to 20, wherein it comprised a step of mineralization of the captured carbon dioxide, performed by passing a CO2 gas stream through an aqueous solution of calcium chloride (CaC12) at 0.1 M, previously alkalized with ammonium hydroxide (NH4OH) and / or monoethanolamine (MEA) , combined with a chitosan membrane or sphere, in order to promote the precipitation of high-purity calcium carbonate (CaCOs) ; the process being conducted in reactors or vertical columns, at room temperature and atmospheric pressure, in continuous or batch mode.

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