Washcoated monoliths for carbon capture

Abstract

In one aspect, CO2 adsorbent coatings are described herein. A coating, in some embodiments, comprises a polymeric binder phase and a particulate CO2 sorbent disposed in the polymeric binder phase, wherein the coating has a macroporosity of 0.4-1.5 cm3 / g in pores of diameter ranging from 0.1 μm to 50 μm. Moreover, in some embodiments, the coating comprises a hierarchical pore structure including mesoporosity of 0.005-0.6 cm3 / g in pores of diameter ranging from 5 μm to 100 μm.

Description

[0001] WASHCOATED MONOLITHS FOR CARBON CAPTURE

[0002] RELATED APPLICATION DATA

[0003] The present application claims priority pursuant to 35 U.S.C. § 119(e) to United States Provisional Patent Application Serial Number 63 / 526,044 filed July 11, 2023 which is incorporated herein by reference in its entirety.

[0004] FIELD

[0005] The present invention relates to monolithic structural bodies for gas treatment applications and, in particular, to such structural bodies employing washcoat compositions for the removal of carbon dioxide (CO2) from gas streams.

[0006] BACKGROUND

[0007] Global warming and associated climate change induced by human activities presents an existential threat to numerous ecosystems and the way of human life as it is currently understood. The mining and burning of fossil fuels are chief contributors global warming via the massive release of heat trapping gases, including methane and carbon dioxide. Carbon dioxide accounts for the bulk of greenhouse gas emissions, as the concentration of carbon dioxide has eclipsed the 400 ppm mark in recent years. Current carbon dioxide levels exceed any concentration in the last 800,000 years.

[0008] In view of this alarming trend in atmospheric carbon dioxide concentration, countries and industry have initiated various mitigation strategies to reduce carbon dioxide emissions, as well as methane emissions. Electrification of vehicles and transportation systems has drawn considerable attention. Moreover, the transition to green / renewable sources of energy, including wind and solar, has received significant private and public investment. While promising, these mitigation strategies fail to address carbon dioxide that is currently in the atmosphere. Accordingly, current carbon dioxide levels are left to slow, natural degradation processes.

[0009] SUMMARY

[0010] In one aspect, washcoat compositions are described herein for application to substrates rendering the substrates operable for the capture of carbon dioxide (CO2) from the ambient atmosphere and / or sources of exhaust gases, including exhaust gases from electrical power generation and industrial facilities. In some embodiments, a washcoat composition comprises an organic continuous phase, a polymeric binder at least partially solubilized in the organic continuous phase, and a particulate carbon dioxide (CO2) sorbent dispersed in the organic continuous phase, the particulate CO2 sorbent having a macroporosity of 0.3-4 cm3 / g in pores of diameter ranging from 0.1 to 50 gm.

[0011] In another aspect, CO2 adsorbent coatings are described herein. A coating, in some embodiments, comprises a polymeric binder phase and a particulate CO2 sorbent disposed in the polymeric binder phase, wherein the coating has a macroporosity of 0.4-1.5 cm3 / g in pores of diameter ranging from 0.1 gm to 50 gm. Moreover, in some embodiments, the coating comprises a hierarchical pore structure including mesoporosity of 0.005-0.6 cm3 / g in pores of diameter ranging from 5 nm to 100 nm.

[0012] In another aspect, monolithic structural gas treatment bodies are described herein. In some embodiments, a monolithic structural gas treatment body comprises a substrate and a coating adhered to the substrate, the coating comprising a polymeric binder phase and a particulate carbon dioxide (CO2) sorbent disposed in the polymeric binder phase, wherein the monolithic structural gas treatment body has a macroporosity of 0.3-3 cm3 / g in pores of diameter ranging 0.1 pm to 50 gm. In some embodiments, the monolithic structural gas treatment body exhibits a hierarchical pore structure including mesoporosity of 0.01-0.8 cm3 / g in pores of diameter ranging from 5 nm to 100 nm. Moreover, in some embodiments, the substrate comprises an outer peripheral wall, and a plurality of inner partition walls defining a plurality of flow channels. The coating is adhered to the inner partition walls within the flow channels.

[0013] These and other embodiments are further described in the following detailed description.

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] FIG. 1 illustrates a honeycomb-like monolithic structural gas treatment body according to some embodiments herein.

[0016] FIG. 2 illustrates flow channels defined by the inner partition walls in a honeycomb-like monolithic structural body according to some embodiments herein.

[0017] FIG. 3 illustrates a method of determining the average thickness of the outer peripheral wall 10 and inner partition walls 11. FIG. 4 is a scanning electron microscopy image of a flow channel of a monolithic structural gas treatment body, according to some embodiments.

[0018] FIG. 5 is an optical image of a structural gas treatment body according to some embodiments.

[0019] FIG. 6 illustrates a plan view of a module containing monolithic structural gas treatment bodies according to some embodiments.

[0020] FIG. 7 is a CO2 adsorption curve for a monolithic structural gas treatment body described herein according to some embodiments.

[0021] DETAILED DESCRIPTION

[0022] Embodiments described herein can be understood more readily by reference to the following detailed description and examples and their previous and following descriptions. Elements, apparatus and methods described herein, however, are not limited to the specific embodiments presented in the detailed description and examples. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations will be readily apparent to those of skill in the art without departing from the spirit and scope of the invention.

[0023] I. Washcoat Compositions

[0024] In one aspect, washcoat compositions are described herein for application to substrates rendering the substrates operable for the capture of CO2 from the ambient atmosphere and / or sources of exhaust gases. In some embodiments, a washcoat composition comprises an organic continuous phase, a polymeric binder at least partially solubilized in the organic continuous phase, and a particulate CO2 sorbent dispersed in the organic continuous phase, the particulate CO2 sorbent having a macroporosity of 0.3-4 cm3 / g in pores of diameter ranging from 0.1 to 50 pm.

[0025] Turning now to specific components, the particulate CO2 sorbent, in some embodiments, comprises a particulate support and one or more chemical functionalities operable for the adsorption of CO2 associated with the support. The particulate CO2 sorbent, for example, can comprise aminated particles. The aminated particles can comprise primary amines, secondary amines, or combinations thereof. Amine functionalities can be associated with polymeric chains including, linear, branched, grafted, dendritic, and / or hyper-branched chains. Such polymeric chains can be coated onto the particulate support or chemically bound to the particulate support. In some embodiments, for example, the particulate CO2 sorbent is commercially available from Lanxess AG of Cologne, Germany under the LEWATIT® trade designation.

[0026] As set forth above, the particulate CO2 sorbent has a macroporosity of 0.3-4 cm3 / g in pores of diameter ranging from 0. 1 to 50 pm. In some embodiments, the macroporosity is 0.7-3 cm3 / g or 1-2 cm3 / g in pores of diameter ranging from 0.1 to 50 pm. Macroporosity of the particulate CO2 sorbent is determined by obtaining 0.5 g of dried particulate CO2 sorbent. The particulate CO2 sorbent is dried at 110°C for 1 hour under a nitrogen (N2) atmosphere. The dried particulate CO2 sorbent is placed in the sample chamber of a mercury penetrometer. The dried particulate CO2 sorbent is not compacted or pressed prior to placement in the sample chamber. Once in the chamber, the macroporosity is determined via Hg intrusion porosimetry (low- pressure-high pressure).

[0027] In addition to the foregoing macroporosity, the particulate CO2 sorbent, in some embodiments, has an average particle size of 1-100 pm. The particulate CO2 sorbent, in some embodiments, exhibits a particle size distribution having a D10 of 0.5-2 pm. The particulate CO2 sorbent can be milled to achieve the foregoing average particle size and D10. Depending on specific compositional identity of the particulate CO2 sorbent, the milling process can begin with drying the particulate CO2 sorbent to a weight loss of at least 50 percent. The dried particulate CO2 sorbent is then dry ball milled for 18-24 hours, followed by sieving with a 50 mesh screen. The milled particulate CO2 sorbent can exhibit the macroporisity values described above for the particulate CO2 sorbent.

[0028] The particulate CO2 sorbent can be present in the washcoat composition in any desired amount. Considerations governing the amount of particulate CO2 sorbent can include the specific identity of the particulate CO2 sorbent, dispersability of the sorbent in the organic continuous phase, and / or desired loading of the sorbent in coatings produced by application of the washcoat composition to various substrates. In some embodiments, the particulate CO2 sorbent is present in an amount of 5-30 weight percent or 10-20 weight percent of the washcoat composition.

[0029] In addition to the particulate CO2 sorbent, the washcoat composition comprises a polymeric binder at least partially solubilized in the organic continuous phase. The polymeric binder, in some embodiments, comprises one or more thermoplastics. Suitable polymeric binder can be selected according to several considerations, including identities of the particulate CO2 sorbent and organic continuous phase. Polymer of the polymeric binder can be homopolymer or copolymer. Suitable copolymers include alternating copolymers, block copolymers, statistical copolymers or random copolymers. In some embodiments, polymer of the polymeric binder comprises heterocyclic monomeric units or acetal monomeric units. Acetal monomeric units can be cyclic or non-cyclic. In some embodiments, acetal monomeric units are employed in combination with other monomeric units, such as alcohols and / or acetates. Polymer of the polymeric binder, for example, can be polyvinyl butyral (PVB) or derivatives thereof.

[0030] The polymeric binder can be present in the washcoat compositions in any desired amount. Considerations governing the amount of polymeric binder in the washcoat composition can include the identity and desired loading of the particulate CO2 sorbent, identity of the substrate being coated, and the desired mechanical properties of the washcoat applied to the substrate. In some embodiments, the polymeric binder is present in an amount of 0.25-10 weight percent or 0.5-5 weight percent of the washcoat composition.

[0031] Specific identity of the organic continuous phase of the washcoat composition can be dependent on the identities of the polymeric binder and the particulate CO2 sorbent. The continuous organic phase at least partially solubilizes the polymeric binder phase. Moreover, the particulate CO2 sorbent should be stable in the continuous organic phase and be resistant to aggregation. In some embodiments, the organic continuous phase is a polar aprotic solvent. The organic continuous phase, in some embodiments, comprises acetone, alcohol, acetate, dimethyl sulfoxide, ketone, alkylene chloride, or mixtures thereof. The organic continuous phase can provide the balance of the washcoat composition. The washcoat composition can be prepared, in some embodiments, by solubilizing the polymeric binder in the organic continuous phase, followed by addition of the particulate CO2 sorbent. Mechanical agitation can be employed to solubilize or dissolve the polymeric binder and / or disperse the particulate CO2 sorbent in the continuous organic phase.

[0032] II. CO2 Adsorbent Coatings

[0033] In another aspect, CO2 adsorbent coatings are described herein. A coating, in some embodiments, comprises a polymeric binder phase and a particulate CO2 sorbent disposed in the polymeric binder phase, wherein the coating has a macroporosity of 0.4-1.5 cm3 / g in pores of diameter ranging from 0.1 pm to 50 pm. In some embodiments, macroporosity of the coating is 0.6-1.0 cm3 / g in pores of diameter ranging from 0.1 pm to 50 pm. Moreover, coatings described herein can also exhibit a hierarchical pore structure including mesoporosity of 0.005-0.6 cm3 / g in pores of diameter ranging from 5-100 nm. In some embodiments, the mesoporosity is 0.01-0.1 cm3 / g or 0.015-0.05 cm3 / g in pores of diameter ranging from 5-100 nm. Macroporosity of the coatings can be determined by mercury intrusion porosimetry, whereas mesoporosity of the coatings is determined by nitrogen (N2) physisorption. Coating samples for macroporosity and mesopori sty determination were prepared by layering the washcoat composition of Section I above on a substrate. Once sufficient thickness of the coating was achieved by multiple applications of the washcoat composition, a portion of the coating was removed from the substrate for analysis.

[0034] In being formed from the washcoat composition, individual components of the coating are consistent with the description in Section I above. The particulate CO2 sorbent and polymeric binder phase, for example, can each have any composition and / or properties described in Section I above. In some embodiments, the particulate CO2 sorbent exhibits a D10 particle size in the polymeric binder of 0.5-2 pm. The particulate CO2 sorbent can be present in the coating in any desired amount. In some embodiments, the particulate CO2 sorbent is present in an amount of 70-95 weight percent of the coating. Additionally, the polymeric binder can be present in the coating in any desired amount. In some embodiments, the polymeric binder is present in an amount of 5-30 weight percent or 5-15 weight percent.

[0035] Coatings described herein can have any desired thickness. As described above, coating thickness is controlled by the number of washcoat layers applied to a substrate. In some embodiments, a coating has a thickness of 100 pm to 1 mm or 200 pm to 750 pm. Coating thickness can be selected according to several considerations including desired stability of the coating and pressure drop effects induced by the coating when applied to the substrate.

[0036] III. Monolithic Structural Gas Treatment Bodies

[0037] In another aspect, monolithic structural gas treatment bodies are described herein. In some embodiments, a monolithic structure gas treatment body comprises a substrate and a coating adhered to the substrate, the coating comprising a polymeric binder phase and a particulate CO2 sorbent disposed in the polymeric binder phase, wherein the monolithic structural gas treatment body has a macroporosity of 0.3-3 cm3 / g in pores of diameter ranging 0.1 pm to 50 pm. In some embodiments, macroporosity of the gas treatment body ranges from 0.4-2 cm3 / g. The monolithic structural gas treatment body can also exhibit a hierarchical pore structure including mesoporosity of 0.01-0.8 cm3 / g in pores of diameter ranging from 5 nm to 100 nm. In some embodiments, the mesoporosity is 0.1-0.5 cm3 / g in pores of diameter ranging from 5 nm to 100 nm.

[0038] As set forth hereinabove, the coating adhered to the substrate is formed by application of the washcoat composition of Section I to the substrate. In being formed from the washcoat composition, individual components of the coating are consistent with the description in Section I above. The particulate CO2 sorbent and polymeric binder phase, for example, can each have any composition and / or properties described in Section I above. In some embodiments, the particulate CO2 sorbent exhibits a D10 particle size in the polymeric binder of 0.5-2 pm. The particulate CO2 sorbent, in some embodiments, is present in an amount of 10-50 weight percent of the monolithic structural gas treatment body. Moreover, the polymeric binder phase, in some embodiments, is present in an amount of 1-10 weight percent of the monolithic structural gas treatment body.

[0039] Additionally, the substrate, in some embodiments, comprises an outer peripheral wall, and a plurality of inner partition walls. The inner partition walls are arranged inside the dimensions defined by the outer peripheral wall, and plurality of flow channels are defined by the inner partition walls, the flow channels extending longitudinally through the monolithic substrate. FIG. 1 illustrates a honeycomb-like monolithic substrate according to some embodiments herein. The honeycomb-like substrate in the embodiment of FIG. 1 comprises an outer peripheral wall 10 and a plurality of inner partition walls 11. The inner partition walls 11 define a plurality of flow channels 12 extending longitudinally through the honeycomb-like monolithic substrate.

[0040] FIG. 2 illustrates flow channels 12 defined by the inner partition walls 11 in a honeycomb-like monolithic substrate according to some embodiments herein. The inner partition walls 11 and their junctures with the outer peripheral wall serve as boundaries for adjacent flow channels 12. When a portion of the outer peripheral wall 10 serves as a boundary for a flow channel 12, that portion may be referred to as an outer peripheral wall segment 13. As illustrated in FIGS. 1 and 2, the flow channels 12 establish a flow channel density or cell density over the inlet and outlet faces of the substrate. A monolithic substrate described herein can have any desired cell density or flow channel density. The monolithic substrate can have a cell density of at least 85 cpsi. In some embodiments, the monolithic substrate has a cell density of 100 cpsi to 900 cpsi. For example, the monolithic substrate can have a cell density of 100 cpsi to 500 cpsi, 140 cpsi to 450 cpsi, or 170 cpsi to 500 cpsi. Additionally, length of the flow channels or cells, in some embodiments, is at least 100 mm or at least 110 mm. In some embodiments, length of the flow channels of cells of the monolithic substrate is at least 120 mm or at least 125 mm. In some embodiments, flow channels of the monolithic substrate can have lengths up to 1200 mm or 1500 mm.

[0041] Inner partition wall thickness of a monolithic substrate, in some embodiments, is 0.1 mm to 0.3 mm. In some embodiments, the inner partition wall thickness can be 0.1 mm to 0.25 mm, 0.1 mm to 0.2 mm, 0.15 mm to 0.25 mm, or 0.15 mm to 0.2 mm. The thickness of the outer peripheral wall and inner partition walls are determined with a caliper or micrometer with a resolution of 0.01 mm. FIG. 3 illustrates a method of determining the average thickness of the outer peripheral wall 10 and inner partition walls 11. The thickness of the outer peripheral wall 10 is measured in twelve (12) different locations on the substrate. The twelve measuring locations comprise three points on each side of the square outer peripheral wall as demonstrated in FIG. 3. The average thickness of the outer peripheral wall 10 is calculated by averaging the values obtained from the twelve (12) measurements. Similarly, the average thickness of the inner partition walls 11 is determined by initially measuring the thickness of the inner partition walls 11 at twelve (12) different locations throughout the substrate body. The inner partition walls 11 are measured in the horizontal and vertical directions as displayed in FIG. 3. The average thickness of the inner partition walls 11 is calculated by averaging the values obtained in the twelve measurements.

[0042] Thin inner partition walls can assist in achieving high cpsi without sacrificing open frontal area of the monolithic substrate and / or inducing undesirable pressure drop sustained by gas flow through the monolithic substrate when coated with the CO2 adsorbent coatings described herein. The open frontal area (OF A) of the monolithic substrate is that portion of the body cross-section available for gas flow on a cross-sectional surface normal to the direction of gas flow. An increased open frontal area can result in more efficient fluid flow characteristics within the monolithic body, which can decrease the pressure drop sustained by fluids passing through the monolithic structural gas treatment body. A monolithic honeycomb-like substrate described herein can have an OFA of at least 65 percent. In some embodiments, the monolithic substrate has an OFA of at least 70 percent or at least 80 percent. OFA of a monolithic substrate can range from 65-90 percent, 65-85 percent, 70-90 percent, 70-80 percent, 75-85 percent, or 80- 90 percent, in some embodiments.

[0043] The honeycomb-like monolithic substrate, in some embodiments, can also have a hydraulic diameter of at least 100 mm. The hydraulic diameter of the monolithic substrate is defined as being equal to the cross-sectional area perpendicular to the direction of flow of the substrate multiplied by four and divided by the value of the outer perimeter of the outer peripheral wall. When the monolithic honeycomb-like substrate displays a circular cross- sectional geometry, the hydraulic diameter is equal to the diameter of the circular cross-sectional area. In the case of a square cross-sectional geometry, the hydraulic diameter is equal to the length or width of a side. Accordingly, the hydraulic diameter characterizes the size of the monolithic substrate and resultant coated monolithic structural gas treatment body, with larger values of hydraulic diameter corresponding to larger monolithic structural gas treatment bodies. In some embodiments, the monolithic structural gas treatment body has a hydraulic diameter of at least 120 mm or at least 130 mm. The hydraulic diameter of the monolithic structural gas treatment body can range from 100 mm to 150 mm, from 120 mm to 150 mm, or from 130 mm to 150 mm. In some embodiments, hydraulic diameter of the monolithic structural gas treatment body can be greater than 150 mm. Hydraulic diameter of the monolithic structure gas treatment body can have an upper limit of 300 mm, in some embodiments.

[0044] The washcoat composition of Section I hereinabove is applied to the honeycomb-like monolithic substrate and monolithic substrates other geometries to fabricate monolithic structural gas treatment bodies. Thickness of the coating can be controlled by the number of washcoat applications. The honeycomb-like monolithic substrate, for example, can be dipped in the washcoat composition for application of the coating. When applied to the honeycomb-like substrate, the coating can coat the entire length of the flow channels, in some embodiments. Moreover, the coating, in some embodiments, can exhibit a uniform or substantially uniform thickness along the length of the flow channels. In being substantially uniform, coating thickness varies less than 10 percent or less than 5 percent along channel length. In some embodiments, coating thickness exhibits a gradient in a direction normal to the flow channel axis. For example, the coating can be thicker in the corners of a flow channel and thinner along the walls of the flow channel. FIG. 4 is a scanning electron microscopy image of a flow channel of a monolithic structural gas treatment body, according to some embodiments. As provided in the micrograph, the coating is thicker in channel corners relative to channel walls. In some embodiments, a coating has a thickness of 100 pm to 1 mm or 200 pm to 750 pm. Coating thickness can be selected according to several considerations, including desired stability of the coating and pressure drop effects induced by the coating when applied to the substrate. FIG. 5 is an optical image of a structural gas treatment body according to some embodiments. As provided in FIG. 5, the coating is adhered to the inner partition walls of the structural gas treatment body.

[0045] In addition to thin inner partition walls, large hydraulic diameter, and porosity provided by the hierarchical pore structure, a monolithic structural gas treatment body described herein also exhibits transverse compressive strength sufficient to permit use of the monolithic body in industrial gas treatment applications. Insufficient transverse compressive strength can preclude arrangement or packing of the monolithic structural gas treatment bodies in modules and / or other configurations for industrial gas treatment applications. When arranged in modules, the monolithic structural gas treatment bodies experience compressive forces resulting from pressure between the gas treatment bodies as they are assembled side-by-side with or without sealing material, and also when stacked on top of each other, with or without sealing material, to form an array large enough to treat a meaningful amount of gas. FIG. 6 illustrates a plan view of a module containing monolithic structural gas treatment bodies according to some embodiments. The module 20 comprises an open metal framework 22 for supporting monolithic structural bodies 24 disposed therein. The monolithic structural gas treatment bodies 24 are arranged side- by-side. In some embodiments, packing material, cement, or silicone resides between one or more sides of adjacent monolithic bodies to prevent gas flow around the monolithic bodies.

[0046] In some embodiments, the monolithic structural gas treatment body exhibits a transverse compressive strength of at least 500 g / cm2. Transverse compressive strength of the monolithic structural gas treatment body can also have a value selected from Table I. Table I - Transverse Compressive Strength (g / cm2)

[0047] The transverse compressive strengths of the monolithic structural bodies of the present invention may be measured with a compressive testing apparatus such as Tinius Olson 60,000 lb. Super “L” Compression Testing Machine that displays a maximum compression load of 30,000 kg and can be obtained from Tinius Olsen of Willow Grove, Pa. Samples for transverse compressive strength testing may be prepared by cutting a monolithic structural body into sections typically of 150 mm in length, but at least 50 mm in length, wherein each section can serve as an individual test sample.

[0048] Ceramic wool of 6 mm thickness may be spread under and over the pressure surface of the sample, and the wrapped sample set in a vinyl bag in the center of the pressure plates. The pressure plates used in the testing may be stainless steel with dimensions of 160 mm x 160 mm. Transverse compression strength is quantified with the side surface on the bottom with the compressive load applied in the direction parallel to the cross-section of the honeycomb structure and perpendicular to the partition walls. The compressive load is thus applied in the direction normal to the direction of flow in the flow channels. The compressive load can be applied as delineated in Table II.

[0049] Table II - Compressive Loads

[0050] The maximum transverse compressive load W (g) withstood by the samples is registered by the apparatus. The transverse compressive strength is subsequently calculated from the maximum compressive load in grams-force (gf) by dividing the value of the maximum compressive load by the surface area over which the load was applied. In embodiments where the monolithic structural body does not lie flat, such as when the body has an overall circular or oval cross-sectional geometry, a subsection of the body is cut from the overall sample for testing. The subsection is cut so as to produce a sample with upper and lower flat surfaces. The remainder of the strength testing proceeds in a manner consistent with that previously described.

[0051] Monolithic substrates of structural gas treatment bodies described herein, in some embodiments, are fabricated from an inorganic oxide composition. In some embodiments, the inorganic oxide comprises at least one of titania (TiCh), alumina (AI2O3), and zirconia (ZrCh). In some embodiments, the inorganic oxide composition is titania based or alumina based. Alumina of the inorganic oxide can comprise one or more polymorphs, including gamma alumina. In being titania or alumina based, titania or alumina is the inorganic oxide present in the highest amount of the composition. In some embodiments, for example, an alumina based inorganic oxide composition comprises alumina in an amount of 40-100 wt.%. Similarly, a titania based inorganic oxide composition, in some embodiments, comprises titania in an amount of 40-100 wt.%.

[0052] The substrate, in some embodiments, comprises the inorganic oxide composition in an amount of 50-100 wt.%. In some embodiments, the inorganic oxide of the carrier does not substantially include oxides of tungsten, vanadium, and / or molybdenum. For example, the inorganic oxide of the substrate comprises less than 5 wt.%, less than 3 wt.%, less than 1 wt.% of oxides of tungsten, vanadium, and / or molybdenum. Moreover, the inorganic oxide composition, in some embodiments, includes less than 100 ppm iron or iron compounds, the iron or iron compounds operable for the oxidation and / or other degradation of CO2 capture functionalities, such as amine functionalities, coated on the substrate. The monolithic substrate may further comprise fillers and / or reinforcement agent, such as glass or ceramic fibers. Alternatively, the monolithic substrates of structural gas treatment bodies described herein can be fabricated from a polymeric material, include thermoplastics and / or thermosets.

[0053] Monolithic structural gas treatment bodies described herein, in some embodiments, have a CO2 adsorption capacity of at least 65 percent of CO2 adsorption capacity of the particulate CO2 sorbent in virgin form. For example, a monolithic structural has treatment body can have a CO2 adsorption capacity of 85-95 percent of CO2 adsorption capacity of the particulate CO2 sorbent in virgin form. Virgin form of the particulate CO2 sorbent refers to the state of the sorbent as received from the commercial supplier or, if not commercially available, prior to any processing of the sorbent for incorporation into a washcoat composition or coating. The same testing conditions are employed for the monolithic structural gas treatment body and virgin sorbent when determining the respective CO2 adsorption capacities.

[0054] Additionally, the coating comprising the polymeric binder phase and particulate CO2 sorbent can exhibit desirable adherence to the monolithic substrate. In some embodiments, adhesion of the coating can be measured by completing two or more cycles of soaking the monolithic structural gas treatment body in water. The monolithic structural gas treatment body is weighed in dry form followed by soaking in room temperature deionized water for 24 hours. The monolithic structural gas treatment body is removed from the water and weighed. The monolithic structural gas treatment body is then dried at 65°C for 10 hours. The dried monolithic structural gas treatment body is then weighed to determine coating loss. In some embodiments, the monolithic structural gas treatment body exhibits less than 2 weight percent or less than 1 weight percent coating loss after at least two soaking cycles.

[0055] These and other embodiments are further illustrated in the following non-limiting examples.

[0056] EXAMPLE 1 - Washcoat Composition

[0057] Particulate CO2 sorbent was obtained from Lanxess AG under the LEWATIT® trade designation and dry ball milled according to the procedure set forth above. Macroporosity of the milled particulate CO2 sorbent was then determined by mercury porosimetry as described herein. The milled particulate CO2 sorbent had a macroporosity of 1.54 cm3 / g and a DIO in the range of 1.4-2 pm.

[0058] Polyvinyl butyral (PVB) binder was obtained from Eastman Chemical of Kingsport, Tennessee under the BUTVAR® trade designation. 12 grams of the PVB binder was dissolved in 500 g of acetone continuous phase with stirring for 30 minutes. 90.50 grams of the particulate CO2 sorbent was then added to the acetone solution to complete the washcoat composition. Loading of the PVB binder was 2.0 weight percent, and loading of the particulate CO2 sorbent was 15.0 weight percent. EXAMPLE 2 - Monolithic Structural Gas Treatment Body

[0059] A honeycomb y-alumina substrate was obtained having the properties in Table III.

[0060] Table III - Substrate Properties

[0061] The honeycomb substrate was dipped in the washcoat composition of Example 1 over 7 cycles. Honeycomb was initially dried using through air flow room temperature air for at least 2 minutes to ensure that the interior of the part is cooled to room temperature. Honeycomb was submerged in slurry for 30-90 seconds. Once removed the channels were cleared with airflow though the cells, and the coated honeycomb was allowed to dry with through air flow for 15 minutes to Ihr. Once complete, the part was further dried at 65°C and low humidity for 1 to 30 hours. The resulting monolithic structural gas treatment body is pictured in FIG. 4.

[0062] The monolithic structural gas treatment body exhibited a macroporosity of 0.57 cm3 / g in pores of 1-50 pm, and a mesoporosity of 0.20 cm3 / g in pores of 5-100 nm in diameter. The monolithic structural gas treatment body also exhibited a surface area (BET) of 65 m2 / g.

[0063] The monolithic structural gas treatment body was subsequently tested for CO2 capture according to the conditions:

[0064] 1. Gas stream - ambient air or simulated air at 35°C with 450 ppm CO2, 20% O2, and 2% H2O by volume; and

[0065] 2. Space velocity of gas stream - 37,000 hr'1.

[0066] The CO2 adsorption profile of the monolithic structural gas treatment body is provided in FIG. 7. The virgin LEWATIT® CO2 sorbent was also tested under the same conditions. The virgin sorbent was tested in the as received state from Lanxess AG. As illustrated in FIG. 7, the monolithic structural gas treatment body exhibited a CO2 adsorption capacity of 0.69 mmol / g of coating, and the virgin sorbent exhibited a CO2 adsorption capacity of 0.77 mmol / g of sorbent. This correlated to at 90.79% CO2 adsorption capacity retention by the monolithic structural gas treatment body relative to the virgin sorbent.

[0067] The monolithic structural gas treatment body was also tested for coating adhesion according to the water soak testing described above. The monolithic structural gas treatment body did not lose any coating over two cycles of the soak testing.

[0068] Various embodiments of the invention have been described in fulfillment of the various objectives of the invention. It should be recognized that these embodiments are merely illustrative of the principles of the present invention. Numerous modifications and adaptations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the invention.

Claims

CLAIMS1. A coating comprising: a polymeric binder phase and a particulate carbon dioxide (CO2) sorbent disposed in the polymeric binder phase, wherein the coating has a macroporosity of 0.4-1.5 cm3 / g in pores of diameter ranging 0.1 pm to 50 pm.

2. The coating of claim 1, wherein the particulate CO2 sorbent has a D10 particle size of 1-3 pm.

3. The coating of claim 2, wherein the particulate CO2 sorbent has a D90 particle size of less than 50 pm.

4. The coating of claim 1, wherein CO2 sorbent is present in an amount of at least 70 weight percent of the coating.

5. The coating of claim 1, wherein CO2 sorbent is present in an amount of at least 80 weight percent of the coating.

6. The coating of claim 1, wherein CO2 sorbent is present in an amount of 70-95 weight percent of the coating.

7. The coating of claim 1, wherein polymeric binder phase is present in an amount of 5-15 weight percent of the coating.

8. The coating of claim 1 having a hierarchical pore structure including mesoporosity 0.005- 0.6 cm3 / g in pores of diameter ranging from 5-100 nm.

9. The coating of claim 8, wherein the mesoporosity is 0.01-0.1 cm3 / g.

10. The coating of claim 1, wherein the particulate CO2 sorbent comprises aminated particles.

11. The coating of claim 10, wherein the aminated particles are polymeric.

12. The coating of claim 1, wherein the polymeric binder is a thermoplastic.

13. The coating of claim 1, wherein polymer of the polymeric binder comprises heterocyclic monomeric units.

14. The coating of claim 1, wherein polymer of the polymeric binder comprises acetal monomeric units.

15. A monolithic structural gas treatment body comprising: a substrate; and a coating adhered to the substrate, the coating comprising a polymeric binder phase and a particulate carbon dioxide (CO2) sorbent disposed in the polymeric binder phase, wherein the monolithic structural gas treatment body has a macroporosity of 0.3-3 cm3 / g in pores of diameter ranging 0.1 pm to 50 pm.

16. The monolithic structural gas treatment body of claim 15, wherein the particulate CO2 sorbent has a DIO particle size of 1-3 pm.

17. The monolithic structural gas treatment body of claim 15, wherein the coating is present in an amount of 10-70 weight percent of the monolithic structural gas treatment body.

18. The monolithic structural gas treatment body of claim 15, wherein the coating is present in an amount of 40-60 weight percent of the monolithic structural gas treatment body.

19. The monolithic structural gas treatment body of claim 15, wherein the particulate CO2 sorbent is present in an amount of 10-50 weight percent of the monolithic structural gas treatment body.

20. The monolithic structural gas treatment body of claim 15, wherein the polymeric binder phase is present in an amount of 1-10 weight percent of the monolithic structural gas treatment body.

21. The monolithic structural gas treatment body of claim 15 having a hierarchical pore structure including mesoporosity 0.01-0.8 cm3 / g in pores of diameter ranging from 5-100 nm.

22. The monolithic structural gas treatment body of claim 15, wherein the particulate CO2 sorbent comprises aminated particles.

23. The monolithic structural gas treatment body of claim 15, wherein polymer of the polymeric binder comprises heterocyclic monomeric units.

24. The monolithic structural gas treatment body of claim 15, wherein polymer of the polymeric binder comprises acetal monomeric units.

25. The monolithic structural gas treatment body of claim 15, wherein the substrate comprises an outer peripheral wall, and a plurality of inner partition walls defining a plurality of flow channels.

26. The monolithic structural gas treatment body of claim 15 having a CO2 adsorption capacity of at least 65 percent of CO2 adsorption capacity of the particulate CO2 sorbent in virgin form.

27. The monolithic structural gas treatment body of claim 15 having a CO2 adsorption capacity of 85-95 percent of CO2 adsorption capacity of the particulate CO2 sorbent in virgin form.

28. The monolithic structural gas treatment body of claim 15, wherein the coating does not delaminate from the substrate after one or more cycles of soaking in water for 24 hours.

29. The monolithic structural gas treatment body of claim 15 having one or more of the following structural features:(a) hydraulic diameter of at least 100 mm;(b) at least 85 cells per square inch (cpsi); (c) open frontal area of at least 65 percent; and / or(d) transverse compressive strength of at least 500 g / cm2.

30. The monolithic structural gas treatment body of claim 15, wherein the substrate comprises one or more inorganic oxides.

31. The monolithic structural gas treatment body of claim 25, wherein the inner partition walls of the substrate have average thickness of the inner partition walls of 0.1 mm to 0.3 mm.

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