Metalloxerogels for selective gas capture

Abstract

The present disclosure relates to metalloxerogels, processes for their preparation, and their use in selective gas capture. The metalloxerogels are reaction products comprising at least one amino substituted silane of Formula 1 and at least one metal salt, optionally together with a substituted silicate, to form a cross-linked metal–silicate sol-gel network having mesoporosity. The composition and ratios of the components may be controlled to tune pore structure and gas selectivity. The metalloxerogels are suitable for capturing gases from gaseous streams or the atmosphere.

Description

[0001] Metalloxerogels for selective gas capture

[0002] FIELD

[0003] The present disclosure generally relates to a metalloxerogel, processes for preparing a metalloxerogel, and applications for metalloxerogels in capturing gases from a gaseous stream or from the atmosphere.

[0004] BACKGROUND

[0005] The selective capture, storage and re-use of gases from the air has become increasingly important in recent decades to help mitigate air pollution and the potentially detrimental effects to human health and the environment. Examples of such gases are ammonia, which is primarily produced in agriculture and intensive livestock farming; carbon dioxide and carbon monoxide, which are produced in various industrial processes, such as those associated with the burning of fossil fuels.

[0006] Although there is increased interest in developing efficient gas capture systems, most systems known to date are inefficient, expensive, complex and not adjustable for different gases.

[0007] Consequently, there is a need to provide a platform technology that allows efficient capture of different gases, including but not limited to carbon dioxide, carbon monoxide, oxygen, ammonia and others.

[0008] SUMMARY

[0009] The present disclosure provides a metalloxerogel, processes for preparing a metalloxerogel), and applications for metalloxerogels. The present inventors have undertaken research and development into methods for capturing gases from gaseous streams or the atmosphere using the metalloxerogels of the present disclosure.

[0010] In one aspect, there is provided a metalloxerogel for selective gas capture comprising one or more metal ions bonded within a cross-linked metal-silicate sol gel network comprising a plurality of pores, wherein the metalloxerogel is a reaction product comprising at least one amino substituted silane of Formula 1 and at least one metal salt, wherein Formula 1 is: R1Si(OR2)2-L-NH2

[0011] Formula 1 wherein:

[0012] R1is a substituted or unsubstituted Ci-ealkyl;

[0013] R2is Ci-ealkyl;

[0014] L is a -Ci-ealkyl- linker group between the silicon and nitrogen atoms; and wherein: the metalloxerogel is selective for gas capture, and the ratio of amino substituted silane to metal ion is between 1 :0.2-1.

[0015] Preferably, the pores are mesoporous. More preferably, at least 50 % of the pores are mesoporous (as measured by N2gas adsorption isotherms, performed at 77K). Even more preferably, at least 50 % of the pores are mesoporous and are between 20 and 50 nm. Porosity and pore size distribution may be measured by N2gas adsorption isotherms, performed at 77K.

[0016] In embodiments, the one or more metal ions may be selected from an alkaline earth metal, a transition metal ion or a post-transition metal ion, or a combination thereof. In an embodiment, the one or more metal ions may be selected from the group comprising or consisting of ionic forms of Ca, Mg, V, Cr, Fe, Co, Ni, Cu, Zn, Al and Ag, or a combination thereof.

[0017] In embodiments, the one or more metal ions may have a % loading of at least 20 mol%. In embodiments, the one or more metal ions may have a % loading of between about 10 mol% to about 50 mol%. The mol% of the metal ion is equal to or less than the mol% of the amino silane.

[0018] In embodiments, the amount of the one or more metal ions may be effective for facilitating gas capture.

[0019] In an embodiment, the metalloxerogel may be a reaction product comprising at least one amino substituted silane, at least one substituted silicate, and at least one metal salt.

[0020] In embodiments, the amino substituted silane may have a % loading of less than or equal to about 90 mol% of the total mol% of the reactants in the metalloxerogel. In embodiments, the amino substituted silane may have a % loading of between about 40 mol% to about 90 mol%.

[0021] In embodiments, the at least one amino substituted silane may be 3-aminopropyl (diethoxy) methyl silane (APEMS).

[0022] In embodiments, the metalloxerogel further comprises at least one substituted silicate as a reagent that forms the reactant product, as described herein. The silicate may be according to Formula 2:

[0023] Si(OR7)4

[0024] Formula 2 wherein:

[0025] R7is Ci-ealkyl.

[0026] In embodiments, the substituted silicate may have a % loading of between about 0 mol% to about 40 mol%. The % loading of the silicate is less than or equal to the mol% of the amino substituted silane.

[0027] In an embodiment or example, the at least one substituted silicate may be tetraethoxysilane (TEOS).

[0028] In an embodiment or example, the metalloxerogel may comprise, consist of or consist essentially of a reaction product comprising (i) an amino substituted silane according to Formula 1; (ii) optionally a substituted silicate according to Formula 2; and (iii) a metal salt wherein the metal ion is selected from the group consisting of ionic forms of Ca, Mg, V, Cr, Fe, Co, Ni, Cu, Zn, Al and Ag.

[0029] In an embodiment or example, the metalloxerogel may comprise, consist of or consist essentially of a reaction product comprising (i) an amino substituted silane, preferably selected from 3-aminopropyl (di ethoxy) methyl silane (APEMS); and (ii) a metal salt wherein the metal ion is selected from the group comprising or consisting of ionic forms of Ca, Mg, V, Cr, Fe, Co, Ni, Cu, Zn, Al and Ag.

[0030] In an embodiment or example, the metalloxerogel may comprise, consist of or consist essentially of a reaction product comprising (i) an amino substituted silane, preferably selected from 3-aminopropyl (di ethoxy) methyl silane (APEMS); (ii) a substituted silicate, preferably tetraethoxysilane (TEOS); (iii) a metal salt wherein the metal ion is selected from the group comprising or consisting of ionic forms of Ca, Mg, V, Cr, Fe, Co, Ni, Cu, Zn, Al and Ag.

[0031] In another aspect, there is provided a process for preparing a metalloxerogel according to any one or more embodiments or examples described herein, the process comprising: (i) mixing an aqueous solution comprising at least one metal salt together with a solvent system comprising at least one amino substituted silane and at least one substituted silicate, optionally one or more additives, to form a wet-gel matrix comprising the one or more metal ions bonded within a cross-linked metal-silicate sol gel network; and (ii) drying the wet-gel matrix to provide a dried metalloxerogel; with the proviso that drying the wet-gel matrix does not involve supercritical CO2.

[0032] In a further aspect, there is provided a process for preparing a metalloxerogel according to one or more embodiments or examples described herein, the process comprising: (i) mixing an aqueous solution comprising at least one metal salt together with a solvent system comprising at least one amino substituted silane in the absence of at least one substituted silicate, optionally one or more additives, to form a wet-gel matrix comprising the one or more metal ions bonded within a cross-linked metal- silicate sol gel network; and (ii) drying the wet-gel matrix to provide a dried metalloxerogel; with the proviso that drying the wet-gel matrix does not involve supercritical CO2

[0033] In embodiments, the process may be a sol gel process and step (ii) comprises: (al) optionally heating the wet-gel matrix to obtain a gel; and (a2) drying the gel by solvent evaporation and / or heat treatment to provide a dried metalloxerogel.

[0034] In another aspect, there is provided a method for selectively capturing a gas from a gaseous stream or atmosphere containing the gas comprising: contacting the gaseous stream or atmosphere with the metalloxerogel according to any one or more embodiments or examples described herein for capturing at least some of the gas from the gaseous stream or atmosphere.

[0035] In embodiments, the gaseous stream or atmosphere may have a gas concentration of less than about 10,000 ppm.

[0036] In embodiments, at least about 50% to 99% of the gas is removed from the gaseous stream or atmosphere. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Preferred embodiments of the present disclosure will be further described and illustrated, by way of example only, with reference to the accompanying drawings in which:

[0038] Figure 1 is an adsorption isotherm of ammonia onto the Series A of metalloxerogel at room temperature.

[0039] Figure 2 is an adsorption isotherm of ammonia onto the Series B of metalloxerogel at room temperature.

[0040] Figure 3 is an adsorption isotherm of ammonia onto the Series C of metalloxerogel at room temperature.

[0041] Figure 4 is an adsorption isotherm of oxygen onto CuCh and CuCl metalloxerogels at room temperature.

[0042] DETAILED DESCRIPTION

[0043] The present disclosure describes the following various non-limiting embodiments, which relate to investigations undertaken to identify processes for selectively capturing a range of different gases from gaseous streams (e.g. atmosphere) containing said gases using metalloxerogels. It has advantageously been found that the metalloxerogels can be used to selectively absorb or adsorb gases from gaseous streams.

[0044] General Definitions and Terms

[0045] In the following description, reference is made to the accompanying drawings which form a part hereof, and which is shown, by way of illustration, several embodiments. It is understood that other embodiments may be utilised, and structural changes may be made without departing from the scope of the present disclosure.

[0046] With regards to the definitions provided herein, unless stated otherwise, or implicit from context, the defined terms and phrases include the provided meanings. Unless explicitly stated otherwise, or apparent from context, the terms and phrases below do not exclude the meaning that the term or phrase has acquired by a person skilled in the relevant art. The definitions are provided to aid in describing particular embodiments, and are not intended to limit the claimed invention, because the scope of the invention is limited only by the claims. Furthermore, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular.

[0047] All publications discussed and / or referenced herein are incorporated herein in their entirety.

[0048] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is solely for the purpose of providing a context for the present disclosure. It is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.

[0049] Throughout this disclosure, unless specifically stated otherwise or the context requires otherwise, reference to a single step, composition of matter, group of steps or group of compositions of matter shall be taken to encompass one and a plurality (i.e., one or more) of those steps, compositions of matter, groups of steps or groups of compositions of matter. Thus, as used herein, the singular forms “a”, “an” and “the” include plural aspects unless the context clearly dictates otherwise. For example, reference to “a” includes a single as well as two or more; reference to “an” includes a single as well as two or more; reference to “the” includes a single as well as two or more and so forth.

[0050] Those skilled in the art will appreciate that the disclosure herein is susceptible to variations and modifications other than those specifically described. It is to be understood that the disclosure includes all such variations and modifications. The disclosure also includes all of the examples, steps, features, methods, compositions, coatings, processes, and coated substrates, referred to or indicated in this specification, individually or collectively, and any and all combinations or any two or more of said steps or features.

[0051] The term “and / or”, e.g., “X and / or Y” shall be understood to mean either “X and Y” or “X or Y” and shall be taken to provide explicit support for both meanings or for either meaning. Unless otherwise indicated, the terms “first,” “second,” etc. are used herein merely as labels, and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Moreover, reference to a “second” item does not require or preclude the existence of lower-numbered item (e.g., a “first” item) and / or a higher-numbered item (e.g., a “third” item).

[0052] As used herein, the phrase “at least one of’, when used with a list of items, means different combinations of one or more of the listed items may be used and only one of the items in the list may be needed. The item may be a particular object, thing, or category. In other words, “at least one of’ means any combination of items or number of items may be used from the list, but not all of the items in the list may be required. For example, “at least one of item A, item B, and item C” may mean item A; item A and item B; item B; item A, item B, and item C; or item B and item C. In some cases, “at least one of item A, item B, and item C” may mean, for example and without limitation, two of item A, one of item B, and ten of item C; four of item B and seven of item C; or some other suitable combination.

[0053] As used herein, the term “about”, unless stated to the contrary, typically refers to + / - 10%, for example + / - 5%, of the designated value.

[0054] It is to be appreciated that certain features that are, for clarity, described herein in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features that are, for brevity, described in the context of a single embodiment, may also be provided separately or in any sub-combination.

[0055] Throughout the present specification, various aspects and components of the invention can be presented in a range format. The range format is included for convenience and should not be interpreted as an inflexible limitation on the scope of the invention. Accordingly, the description of a range should be considered to have specifically disclosed all the possible sub-ranges as well as individual numerical values within that range, unless specifically indicated. For example, description of a range such as from 1 to 5 should be considered to have specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 5, from 3 to 5 etc., as well as individual and partial numbers within the recited range, for example, 1, 2, 3, 4, 5, 5.5 and 6, unless where integers are required or implicit from context. This applies regardless of the breadth of the disclosed range. Where specific values are required, these will be indicated in the specification.

[0056] Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

[0057] Throughout this specification, the term “consisting essentially of’ is intended to exclude elements which would materially affect the properties of the claimed composition.

[0058] Throughout this specification the word “consisting of’ will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, and the exclusion of any other element, integer or step, or group of elements, integers or steps.

[0059] The terms “comprising”, “comprise” and “comprises” herein are intended to be optionally substitutable with the terms “consisting essentially of’, “consist essentially of’, “consists essentially of’, “consisting of’, “consist of’ and “consists of’, respectively, in every instance.

[0060] Herein the term “about” encompasses a 10% tolerance in any value or values connected to the term.

[0061] The reference to “substantially free” generally refers to the absence of that compound or component in the composition other than any trace amounts or impurities that may be present, for example this may be an amount by weight % in the total composition of less than about 1%, 0.1%, 0.01%, 0.001%, or 0.0001%. The compositions as described herein may also include, for example, impurities in an amount by weight % in the total composition of less than about 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.01%, 0.001%, or 0.0001%. For example, this may be an amount by vol. % in the total gaseous stream of less than about 0.001%, or 0.0001%. For example, the gaseous streams as described herein may also include, for example, impurities in an amount by vol. % in the total gaseous stream of less than about 0.01%, 0.001%, or

[0062] 0.0001%.

[0063] Herein “weight %” may be abbreviated to as “wt.%”. The term “alkyl” includes straight-chained and branched, and includes both unsubstituted and substituted alkyl groups. In one example, the alkyl groups are straight-chained and / or branched alkyl groups. Unless otherwise indicated, the alkyl groups typically contain from 1 to 6 carbon atoms. The alkyl groups may for example contain carbon atoms from 1 to 6, 1 to 5, 1 to 4, 1 to 3 or 1 to 2. Examples of “alkyl” as used herein include, but are not limited to, methyl, ethyl, n-propyl. n-butyl, n-pentyl, isobutyl, t-butyl, isopropyl, cyclopentyl, cyclohexyl and the like. Unless otherwise noted, alkyl groups may be mono- or polyvalent. The alkyl groups may be optionally substituted and / or optionally interrupted by one or more heteroatoms. The alkyl groups may be referred to as “-alkyl-“ in relation to use as a bivalent or polyvalent linking group.

[0064] The term "alkylsilyl" represents an alkyl group that is linked to the rest of the molecule through the silicon atom, which may be unsubstituted or substituted with up to three independently selected alkyl groups in which each alkyl group is as defined supra.

[0065] It will be appreciated by a person of skill in the art that the term “metal”, as used throughout this specification, refers to chemical elements that form metallic structures under ordinary conditions. Metal ions, as referred to herein, may include metallic elements from group 1 to group 17 of the Periodic Table of Elements. Unless specified otherwise, metal ions of the present disclosure may include alkali metal ions, earth alkali metal ions, transition metal ions and post-transition metal ions. Unless specified otherwise, the metal is in its ionic form as a positively charged metal cation.

[0066] Unless specified otherwise, the term “salt” refers to a chemical compound comprising an ionic assembly of positively charged cations and negatively charged anions. When the cation is a metal cation it may be referred to as “metal salt” or “metal ion”. Typical anions forming the salt include inorganic and organic anions, including but not limited to chloride, fluoride, iodide, acetate, sulfate, carbonate, hydroxide, and oxide.

[0067] The term “selective” in the context of gas absorbance or capture refers to the absorbance or capture of a particular gas in preference to other gases present in a gaseous stream. For example, the term “selective” may mean that more than 50% of a particular gas is preferentially absorbed from a mixture of gases. Preferably, more than 60%, or more than 70%, or more than 80%, or more than 90% of a particular gas is selectively absorbed from a mixture of gases. Alternatively, the selective absorption may be expressed in a range. For example, between about 50% to about 99%, or between about 60% to about 99%, or between about 70% to about 99%, or between about 80% to about 99%, or between about 90% to about 99% of a particular gas may be absorbed from a mixture of gases.

[0068] Metalloxerogels and processes for preparing the same

[0069] The present disclosure relates to metalloxerogels and various applications in the selective capture of gases from the atmosphere and / or gaseous streams.

[0070] It will be appreciated that the selection of each component of the metalloxerogel, as well as the process conditions, plays an important role in defining the properties of the metalloxerogels of the present disclosure. In some embodiments, the metalloxerogel may be capable of selective gas capture. The present inventors have surprisingly found that the metalloxerogel composition can be tailored to provide improved control and selectivity for increased gas absorption or adsorption efficiency.

[0071] The metalloxerogels described herein are designed to provide a highly tunable and efficient platform for selective gas capture. These materials may be formed through a sol-gel process involving amino substituted silanes and metal ions, optionally in combination with substituted silicates. One or more advantages of the present invention according to at least some embodiments or examples as described herein lies in the ability to precisely control the ratio of these components, which may directly influence the porosity, surface area, and gas adsorption characteristics of the resulting metalloxerogel. It has been found that maintaining an excess of amino substituted silane relative to the metal ion, the metalloxerogels form open, porous networks that may facilitate rapid gas diffusion and high adsorption capacity. This excess may ensure that metal ions are well -dispersed and coordinated within the matrix, avoiding aggregation and promoting uniform distribution of active sites. The amino groups may serve as coordination points for metal ions, enabling the formation of stable, flexible structures that are not overly crosslinked. The use of amino substituted silanes with two alkoxy groups (i.e., where n = 2) further contributes to reduced crosslinking density of the siloxane backbone. This can allow the metalloxerogels to retain their structural integrity during drying, minimizing shrinkage and cracking, and resulting in materials with consistent pore architecture and mechanical robustness.

[0072] The optional addition of a substituted silicate can act as a covalent crosslinker that can be used to modulate the rigidity and density of the network. However, the metalloxerogels can be effectively synthesized without the substituted silicate, offering flexibility in formulation and enabling the formation of linear polymer segments that are held together primarily by metal-amine coordination. This is particularly advantageous for applications requiring low-density, high-surface-area materials.

[0073] It will be appreciated that the present metalloxerogels are suitable for a wide range of gas capture applications, including the adsorption of ammonia (NH3), carbon monoxide (CO), oxygen (O2), ethylene oxide (EO), nitrogen oxides (NOX), hydrogen (H2), water (H2O), hydrogen fluoride (HF). In another embodiment, the gas may be selected from oxygen (O2) or ammonia (NH3). In another embodiment, the gas may be ammonia (NH3) and / or oxygen (O2) and the metalloxerogel may be a copper comprising metalloxerogel. In another embodiment, the gas may be oxygen (O2) and the metalloxerogel may be a copper comprising metalloxerogel. In yet another embodiment, the gas may be ammonia (NH3) and the metalloxerogel may be a zinc comprising metalloxerogel. In another embodiment, the gas may be ammonia (NH3) and the metalloxerogel may comprise Cu(I), Cu(II), or Zn(II). In another embodiment, the gas may be carbon monoxide (CO) and the metalloxerogel may comprise Cu(I). In another embodiment, the gas may be oxygen (O2) and the metalloxerogel may comprise Cu(I), Cu(II), Co(II), or Fe(II). In another embodiment, the gas may be nitric oxide (NO) and the metalloxerogel may comprise Fe(IVIII), Zn(II), or Ag(I). In another embodiment, the gas may be nitrogen dioxide (NO2) and the metalloxerogel may comprise Fe(II / III) or Zn(II). In another embodiment, the gas may be water (H2O) and the metalloxerogel may comprise one or more metal ions. In another embodiment, the gas may be hydrogen fluoride (HF) and the metalloxerogel may comprise Cu(I), Cu(II), Zn(II), or Fe(II / III). In yet another embodiment, the gas may be a toxic industrial chemical (TIC) selected from ethylene oxide (EO) or hydrogen (EE), and the metalloxerogel may comprise Cu(I), Cu(II), Zn(II), or Fe(IVIII). Their performance can be tailored by adjusting the ratios of amino substituted silane, metal ion, and substituted silicate, allowing for fine control over pore size distribution, surface chemistry, and gas selectivity.

[0074] Unlike conventional systems that rely on high silicate content where the amino silane backbone has a high degree of cross linking creating rigid 3D networks, the present invention enables the formation of porous, crosslinked networks, useful for selective gas adsorption, desorption or gas storage. This versatility may provide for metalloxerogels suitable for integration into compact, low-pressure devices for environmental monitoring, industrial filtration, and aerospace applications.

[0075] In some embodiments or examples, the metalloxerogel may have a BET surface area in a range of from about 10 m2 / g to about 1000 m2 / g, for example from about 100 m2 / g to about 900 m2 / g. The metalloxerogel may have a BET surface area (m2 / g) of at least about 10, 20, 50, 100, 200, 300, 400, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950 or 1000. In other embodiments or examples, the metalloxerogel may have a BET surface area (m2 / g) of less than about 1000, 950, 900, 850, 800, 750, 700, 650, 600, 550, 500, 400, 300, 200, 100, 50, 20, or 10. Combinations of these surface area values to form various ranges are also possible, for example the metalloxerogel may have a BET surface area of between about 20 m2 / g to about 900 m2 / g, about 50 m2 / g to about 800 m2 / g, for example about 450 m2 / g to about 850 m2 / g. The BET surface area may be measured by N2 gas adsorption isotherms, performed at 77K.

[0076] It may be beneficial to define the metalloxerogels by their density. It will be appreciated that density is defined herein as bulk density of the metalloxerogel powder. The bulk density may be measured in accordance with ASTM C29, or for example, as follows: a 1 mL vile is filled with metalloxerogel powder and the weight of metalloxerogel fitting into the 1 mL vile is measured. It will be understood that 1 g of metalloxerogel in a 1 mL vile corresponds to a metalloxerogel having a density of 1 g / cm3. In some embodiments or examples, the density of the metalloxerogel may be in a range of from about 0.02 g / cm3to about 3.0 g / cm3, for example from about 0.1 g / cm3to about 1.5 g / cm3. The density of the metalloxerogel may be at least about 0.02, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75, 0.8, 0.85, 0.9, 0.95, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7,

[0077] 2.8, 2.9 or 3.0 g / cm3. In other embodiments or examples, the density of the metalloxerogel may be less than about 3.0, 2.9, 2.8, 2.7, 2.6, 2.5, 2.4, 2.3, 2.2, 2.1, 2.0,

[0078] 1.9, 1.8, 1.7, 1.6, 1.5, 1.4, 1.3, 1.2, 1.2, 1.0, 0.95, 0.9, 0.85, 0.8, 0.75, 0.7, 0.65, 0.6, 0.55, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.1, 0.05 or 0.02 g / cm3. Combinations of these density values to form various ranges are also possible, for example the metalloxerogel may have a density of between about 0.02 g / cm3to about 2.6 g / cm3, about 0.05 g / cm3to about 1.5 g / cm3, about 0.15 m2 / g to about 0.7 g / cm3, for example, about 0.2 m2 / g to about 0.6 m2 / g, or about 0.3 m2 / g to about 2.4 m2 / g. It will be appreciated that the density of the metalloxerogel can be optimised by variation in the amount of the covalent crosslinker (e.g. the substituted silicate component, TEOS) and / or the amount of metal / amino substituted silane. Higher density metalloxerogels would be most suited for application where weight is a consideration. Formulations with high density can be used for gas adsorption-desorption devices that may fit into restricted spaces or environments. These types of devices can be typically used in space, aerospace, underwater vehicles or platforms. For example, in aerospace or space applications where metalloxerogels can be used to capture gas from atmospheric air. Formulations with low density may be suitable when space is not an issue.

[0079] The metalloxerogel can be provided in a range or morphologies. Illustrative examples of suitable morphologies may include particles, powders, pellets, beads, coatings, sheets / layers, cast blocks, cylinders, discs, porous membranes and monoliths. For example, the metalloxerogel may be provided as a plurality of pellets. For example, the metalloxerogel may be provided as a film / coating layer, a gel layer where the gaseous stream may be flowed thereon or through the layer. Such layers may be a provided as a rolled sheet or a 3D substrate. Alternatively, the metalloxerogel layer may also be provided as a monolith comprising a plurality of porous channels, wherein the gaseous stream flows through. Other layer or coating morphologies and geometries are also applicable.

[0080] In one embodiment or example, the metalloxerogel may comprise a plurality of particles. The term “particle” (also referred to as “particulate”) refers to the form of discrete solid units. The units may take the form of flakes, fibres, agglomerates, granules, pellets, powders, beads, spheres, pulverized materials or the like, as well as combinations thereof. The particles may have any desired shape including, but not limited to, cubic, rod like, polyhedral, spherical or semi-spherical, rounded or semirounded, angular, irregular, and so forth. The particle morphology can be determined by any suitable means such as optical microscopy.

[0081] In some embodiments or examples, the metalloxerogel may be a plurality of particles, powders, pellets, beads, granules, coatings, or sheets / layers. For example, the metalloxerogel may be provided as a plurality of particles, powders, pellets. In one example, the metalloxerogel may be provided as a plurality of pellets.

[0082] In another embodiment, the metalloxerogel may be self-supporting. The term “self-supporting” as used herein refers to the ability of the metalloxerogel to maintain its morphology in the absence of a support material (e.g. scaffold). For example, the metalloxerogel may comprise a plurality of particles, wherein the particles maintain their morphology in the absence of a scaffold support. The self-supported nature of the metalloxerogel may provide certain advantages, for example allows particles of metalloxerogel to be contacted with the gaseous stream using a fluidized bed reactor. Accordingly, in one embodiment or example, the metalloxerogel does not comprise a separate support structure, such as a separate porous support structure. This does not preclude from the metalloxerogel itself being porous in nature. Thus, it will be understood that, where the metalloxerogel is “self-supporting”, there is no support material (e.g. scaffold) exogenous to the metalloxerogel.

[0083] In yet another embodiment, the metalloxerogel may be provided as layer within a column, wherein the gaseous stream may be flowed through the column and passes through the metalloxerogel layer. The layer may not be limited to any particular metalloxerogel morphology. In one example, a suitable column may be packed with a plurality of metalloxerogel particles to form a packed bed with sufficient interstitial space between adjacent particles to allow a flow of gas therethrough. Alternatively, the metalloxerogel may be provided in flow with the gaseous stream (e.g. a fluidised bed reactor). In yet another embodiment, the metalloxerogel may be provided as a coating composition on a substrate. In some embodiments or examples, the substrate may be planar, for example a planar sheet. In a particular example, the substrate may be a flexible sheet. A planar substrate provides a two-sided element onto which the metalloxerogel coating composition can be applied. Each substrate may be coated with the metalloxerogel coating composition on two opposing sides. The planar substrate can have any configuration. In some embodiments or examples, the planar substrate may comprise a flat solid surface. In other embodiments or examples, the planar substrate may comprise one or more apertures, designed to assist gas flow through and around the substrate. In a particular embodiment or example, the substrate may comprise a mesh, for example, micro wire mesh. The use of a mesh provides a multitude of apertures, (e.g. micro size apertures), thereby providing a high surface area on which the metalloxerogel coating composition can be applied, whilst also providing a suitable flow path having a reasonably low pressure drop across the substrate (relative to the size and configuration of the mesh) compared to other configurations, for example, packed beds.

[0084] The metalloxerogel may comprise one or more metal ions bonded within a crosslinked metal-silicate sol gel network. In some embodiments, the one or more metal may be selected from alkali metal ions, alkaline earth metal ions, transition metal ions, posttransition metal ions, or a combination thereof.

[0085] In embodiments, the metalloxerogel may be a reaction product comprising at least one amino substituted silane and at least one metal salt. The inventors have surprisingly found that a metalloxerogel with the desired properties can form from an amino substituted silane and a metal. While not essential for the formation of a metal- silicate network, it may be beneficial to further add a substituted silicate as a reagent when forming the metalloxerogel reaction product. Hence, in embodiments, the metalloxerogel may be a reaction product comprising at least one amino substituted silane, at least one substituted silicate and at least one metal salt. Without wishing to be bound by theory, it is hypothesised that the pore size of the metalloxerogel can be optimised for selective gas adsorption by varying the amount of the at least one amino substituted silane and the amount of the metal. It has been surprisingly found that the amount of metal ion may further facilitate the formation of a mesoporous structure through crosslinking with the substituted silicate component forming a cross-linked metal-silicate sol gel network. In an embodiment, the metalloxerogel may comprise a plurality of pores, wherein at least 50 % of the pores are mesoporous (as measured by N2 gas adsorption isotherms, performed at 77K). In other words, at least 50 % of the pores are greater than 2 nm. Preferably, at least 50 % of the pores are mesoporous and are between 20 and 50 nm. It will be understood that porosity and pore size distributions of the metalloxerogels may be measured by N2 gas adsorption isotherms, performed at 77K.

[0086] In embodiments, the metalloxerogel may be effective for facilitating gas capture. While it is known in the art that the amino group can facilitate carbon dioxide gas capture, it has been surprisingly found that the incorporation of one or more metal ions into the cross-linked metal-silicate sol gel network facilitates formation of a tuneable structure that allows the selective capture of a range of other gases, different to carbon dioxide, such as sorption of toxic industrial gases or adsorption of industrially useful gasses such as ammonia and oxygen. It has therefore been found that the metalloxerogels of the present disclosure are a platform technology which can be used and tuned to target specific gases and remove them from a gaseous stream or the atmosphere. One or more advantages of the present disclosure according to at least some embodiments or examples as described herein is that the amount of metal ion can be adjusted to form an metalloxerogel comprising either water absorbing properties, water resisting properties, or a combination of both within the same framework. It has been found that although metalloxerogels with low amounts of metal ion content will be hydrophobic, the metalloxerogels made with higher amounts of metal ion content will show increased water sorption, due to exposed metal sites, therefore the water absorbing / water resisting properties may be tuneable.

[0087] In some embodiments or examples, the backbone of the metalloxerogel comprises a reaction product of at least one amino substituted silane and at least one metal. In other embodiments or examples, the backbone of the metalloxerogel comprises a reaction product of at least one amino substituted silane, at least one substituted silicate and at least one metal. The backbone may comprise a siloxane backbone with a plurality of pendant groups selected from amino alkyl groups and alkyl groups. It will be appreciated that due to the hydrophobic alkyl groups present in the siloxane backbone, and only two siloxane bonds available per silicon atom, the metalloxerogels, as described herein, may generally have a lower cross-linking density and higher deformability than those derived from the conventional tetraalkoxysilanes. These advantageous characteristics may provide greater potential for further engineering the fine structures of the metalloxerogels for achieving low volume shrinkage by the drying process without the use of further solvent exchange and surface modification.

[0088] In embodiments, there is provided a metalloxerogel for selective gas capture comprising one or more metal ions bonded within a cross-linked metal-silicate sol gel network comprising a plurality of pores, wherein the metalloxerogel is a reaction product of at least one amino substituted silane according to Formula 1 and at least one metal salt, wherein Formula 1 is: R1Si(OR2)2-L-NH2, wherein: R1is substituted or unsubstituted Ci-ealkyl; R2is Ci-ealkyl; L is a -Ci-ealkyl- linker group between the silicon and nitrogen atoms; andwherein: the metalloxerogel is selective for gas capture, and the ratio of amino substituted silane to metal ion is between 1 :0.2-1.

[0089] In embodiments, the amount of the amino substituted silane may be in a range of from about 40 mol% to about 90 mol%.

[0090] In an embodiment, the metaalloxerogel may further comprise a substituted silicate according to Formula 2: Si(OR7)4, wherein: R7may be Ci-ealkyl which is used in combination with the amino silane and metal salt to form the metalloxerogel reaction product. In some embodiments or examples, the amount of substituted silicate may be in a range between about 0 mol% to about 40 mol% based on the total mol% of reagents forming the metalloxerogel. The mol% of silicate is less than or equal to the mol% of the amino silane.

[0091] In an embodiment, the metal salt may be an alkali metal salt, an alkaline earth metal salt, a transition metal salt, or a post-transition metal salt, or a combination thereof.

[0092] In an embodiment or example, the metal-silica metalloxerogel may comprise, consist essentially of or consist of a reaction product comprising (i) at least one amino substituted silane, preferably 3-aminopropyl (diethoxy) methyl silane (APEMS); (ii) optionally at least one substituted silicate, preferably tetraethoxysilane (TEOS); and (iii) at least one metal ion, wherein the metal ion is selected from the group consisting of ionic forms of Ca, Mg, V, Cr, Fe, Co, Ni, Cu, Zn, Al and Ag, or a combination thereof.

[0093] In some embodiments or examples, there is provided a process for preparing a metalloxerogel. In particular, the present disclosure provides a process for preparing a metalloxerogels, as described herein, from the reaction product comprising at least one amino substituted silane, optionally at least one substituted silicate, and at least one metal salt. In some embodiments, the process for preparing a metalloxerogel may comprise or consist of: (i)(a) mixing an aqueous solution comprising at least one metal salt together with a solvent system comprising at least one amino substituted silane, preferably according to Formula 1, and at least one substituted silicate, preferably according to Formula 2 (Series B and C), optionally a buffer, optionally one or more additives, to form a wet-gel matrix comprising the metalloxerogel; and (ii) drying the wet-gel matrix to provide a dried metalloxerogel, with the proviso that drying the wetgel matrix does not involve supercritical CO2. In some embodiments or examples, step (i) further comprises step (i)(b) rinsing the wet-gel matrix prior to step (ii). Rinsing the wet gel enables solvent exchange and the removal of by-products within the pores of the materials. Alternatively, the process for preparing a metalloxerogel may comprise or consist of: (i)(a) mixing an aqueous solution comprising at least one metal salt together with a solvent system comprising at least one amino substituted silane, preferably according to Formula 1, without the inclusion of a silicate according to Formula 2 (Series A), optionally a buffer, optionally one or more additives, to form a wet-gel matrix comprising the metalloxerogel; and (ii) drying the wet-gel matrix to provide a dried metalloxerogel, with the proviso that drying the wet-gel matrix does not involve supercritical CO2. In some embodiments or examples, step (i) further comprises step (i)(b) rinsing the wet-gel matrix prior to step (ii). Rinsing the wet gel enables solvent exchange and the removal of by-products within the pores of the materials. One or more advantages of the present process according to at least some embodiments or examples as described herein is that the process is a scalable one pot synthesis with short reaction times (e.g. approx. 6 hours for some formulations compared to 48 hours or more) and gelation times (e.g. approx. 5 to 30 minutes) to prepare mesoporous metalloxerogels capable of gas capture. The synthesis and washing steps require an oven or water bath and rudimentary reaction vessels. No specialised gasses or pressure vessels are necessary for the described process, and the typical density of the preferred candidates may be in the range of 0.3 to 0.8g / mL, allowing smaller volume of metalloxerogel to be used in practical manifestations of a gas capture apparatus. Furthermore, the drying does not require supercritical drying using CO2, freeze drying or any other harsh drying conditions. Hence, the financial advantages in both synthesis cost and equipment costs are greatly advantageous.

[0094] For example, in step (i)(a), the mixing may proceed at ambient temperature for at least 24 hours or may be heated to between about 60°C and about 80°C for about 6 hours. In step (i)(b), rinsing the wet-gel matrix in a sufficient amount of water to exchange solvent (e.g. ethanol) with water allows the wet-gel matrix to dry (in step (ii)) to form an open porous gel (e.g. a dried metalloxerogel). Failure to remove the solvent may result in a “hard” gel with poor performance. The wet-gel matrix rinsed in sufficient amounts of water to remove the solvent can be dried at room temperature and heated between about 80°C and 100°C to remove any residual water.

[0095] In some embodiments or examples, the process may be a sol gel process and step (ii) may comprise or consists of: (al) optionally heating the wet gel matrix to obtain a gel; and (a2) drying the gel by solvent evaporation and / or heat treatment to provide a dried metalloxerogel.

[0096] In other embodiments or examples, the process may comprise an alternate step (ii) which may comprise: (bl) wherein the wet gel matrix may be applied to a substrate to form a wet-gel film coating the substrate; and (b2) drying the wet-gel film by solvent evaporation and / or heat treatment to provide a dried silica-based coated substrate. In an embodiment or example, the drying step (ii) may be vacuum drying or ambient pressure drying at below 80 °C. It will be appreciated that the drying step (ii) does not involve supercritical CO2.

[0097] In step (i) an alcogel or step (al) a sol gel (e.g. a colloidal solution) may be formed from the process that gradually evolves towards the formation of a gel -like diphasic system containing both the liquid phase and the solid phase whose morphologies may range from discrete particles to continuous polymer networks (ageing process). In some embodiments or examples, the particle density may be low such that an amount of liquid may need to be removed initially for the gel -like properties to be recognized. In another embodiment or example, centrifugation may be used to accelerate the process of phase separation and gel formation to form the aged alcogel or aged sol gel. Removal of the remaining liquid (solvent) phase may require a drying step (for example, step (ii) and step (a2)).

[0098] Faster gelation at a higher temperature may involve accelerated chemical reactions and cluster aggregation, leading to relatively larger voids (or pores) in the metalloxerogel, while slower gelation at a lower temperature may give rise to smaller voids (or pores).

[0099] Without wishing to be bound by theory, it is hypothesised that the addition of a substituted silicate increases the rigidity of the metal-silicate network structure as it forms covalent bonds to four other silicon atoms. The amino substituted silane may form only two covalent bonds in the siloxane network structure allowing flexibility.

[0100] Prior to step (al) and (bl) the wet-gel matrix may be heated to a suitable temperature and maintained at the temperature (ageing process). In some embodiments or examples, the wet-gel matrix may be heated in a range between about 20°C and about 100°C. The temperature of the wet-gel matrix may be at least about 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95 or 100°C. The temperature of the wet-gel matrix may be less than about 100, 95, 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, 40, 35, 30, 25 or 20°C. Combinations of these heating temperatures are also possible, for example between about 20°C to about 30°C, about 25°C to about 80°C, or about 75°C to about 85°C.

[0101] At least according to some embodiments or examples as described herein, the wet-gel matrix may be heated to the desired temperature by immersing the reaction vessel in an oven at the required temperature and the solution allowed to reach the required temperature.

[0102] At least according to some embodiments or examples as described herein, the wet-gel matrix may be maintained at the temperature in step (al) and (bl) for about 3 hours to about 24 hours. The wet-gel matrix may be maintained at the temperature of step (al) and (bl) for at least about 3, 6, 9, 12, 15, 18, 21 or 24 hours. The wet-gel matrix may be maintained at the temperature of step (al) and (bl) for less than 24, 21, 18, 15, 12, 9, 6 or 3 hours. Combinations of these times are also possible, for example between about 6 hours and about 12 hours.

[0103] In some embodiments or examples, the wet-gel matrix may then be cooled to ambient temperature for step (al) and (bl). In an embodiment or example, the wet -gel matrix may be cooled to ambient temperature.

[0104] In an example, after formation of the wet-gel, residual solvent and organic reaction products may be removed to avoid plasticizing the wet-gel matrix. These are interchanged with water by breaking up the matrix and soaking in at least 10 times excess of water, for no less than 1 hour. The water interchange may protect the wet-gel matrix from collapsing and also may allow any unreacted silanes to form Si-O-Si bonds. Insufficient interchange of water may result in gels that do not resemble typical metalloxerogels dried using traditional methods. The incorporation of amino substituted silanes such as those of Formula 1 (e.g. 3 -aminopropyl (di ethoxy) methyl silane) means that the solvated matrix still has plastic properties, unlike the traditional metalloxerogels where all the silicon atoms are covalently bound to no fewer than three other oxygen atoms.

[0105] Conventional processes may use super-critical CO2 as part of the drying process of silica-based gels. However, supercritical drying is performed at high pressure and increases manufacturing costs, thereby providing an obstacle in commercialization of silica-based gels.

[0106] One or more advantages of the present process according to at least some embodiments or examples as described herein is that the wet-gel matrix may be dried to obtain a dried metalloxerogel by minimising the effects previously observed with other drying processes. The drying process described by the present disclosure may be performed in various advantageous ways, including reduced pressure drying, ambient pressure or in a vacuum drying, or various combinations thereof. Preferably, vacuum drying or ambient pressure drying in an oven at below about 80 °C. For step (ii) the wet-gel matrix may be dried at a temperature suitable to produce a dried metalloxerogel. In an example, when the wet-gel matrix is dried using reduced pressure drying, the drying equipment may be controlled at about 40 to about 60°C, or about 55°C, the initial drying pressure may be ambient atmospheric pressure, and the vacuum pump may be turned on to start vacuum drying (-80kPa) for at least about 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hour, 18 hours, 20 hours, 22 hours or 24 hours, to produce the dry metalloxerogel. In another example, when the wet-gel matrix is dried using ambient pressure or in an oven, the temperature may be controlled at between about 40°C to about 80°C, or at between at about 40°C to about 60°C, or about 50°C and the wet-gel matrix is maintained under ambient pressure or in a vacuum for at least about 4 hours, 6 hours, 8 hours, 10 hours, 12 hours, 14 hours, 16 hour, 18 hours, 20 hours, 22 hours or 24 hours, to produce the dry metalloxerogel.

[0107] In some embodiments or examples, the solvent may be water, a non-aqueous solvent, or a combination thereof. A variety of non-aqueous solvents may be used in step (i)(a) and step (i)(b) of the process, including alcohols containing between 1 and 6 carbon atoms. In an embodiment or example, the solvent may be selected from methanol, ethanol, propanol, butanol, isobutyl alcohol, t-butyl alcohol, pentanol, hexanol, and combinations thereof. In one embodiment or example, ethanol may be used as the solvent. For example, ethanol may be used in combination with water in the process. Water in various ratios may also be involved to accomplish the sol-gel reactions. Water may also be a product of some of these reactions. The ratios and solvents may be adjusted so that precipitation or phase separation can be avoided.

[0108] In some embodiments or examples, the process may further comprise step (iii) an activation step. The metalloxerogels prepared by the process may be activated at temperature in a range or about 80°C to about 160°C. The activation temperature may be at least about 80, 90, 100, 110, 120, 130, 140, 150 or 160°C. The activation temperature may be less than about 160, 150, 140, 130, 120, 110, 100, 90 or 80°C. Combinations of these activation temperatures are possible, for example the activation temperature may be between about 80°C to about 160°C, between about 90°C to about 150°C, or between about 100°C to about 140°C. Amino substituted silane

[0109] In some embodiments or examples, the amino substituted silane may comprise at least one or more aliphatic amine groups (e.g. an amine wherein no aromatic ring groups are directly bound to the nitrogen atom of the amine).

[0110] In some embodiments or examples, the amino substituted silane may be according to Formula 1 :

[0111] R1mSi(OR2)2-L-NH2

[0112] Formula 1 wherein:

[0113] R1may be substituted or unsubstituted Ci-ealkyl;

[0114] R2may be Ci^alkyl;

[0115] L is a -Ci-ualkyl- linker group between the silicon and nitrogen atoms; and wherein: the metalloxerogel is selective for gas capture, and the ratio of amino substituted silane to metal ion is between 1 :0.2-1.

[0116] In some embodiments or examples, the amino substituted silane may comprise a Ci-ealkyl which may be provided by any alkyl as described above or herein having a 1 to 6 atom chain.

[0117] In some embodiments or examples, the amino substituted silane may comprise a Ci-4alkyl which may be provided by any alkyl as described above or herein having a 1 to 4 atom chain.

[0118] The alkyl groups of the amino substituted silane may comprise between 1 and 4 carbon atoms. The alkyl groups may be methyl, ethyl, propyl, n-butyl, t-butyl or other higher carbon alkyl groups. In some embodiments or examples, the amino substituted silane may be 3 -aminopropyl (di ethoxy) methyl silane (APEMS)

[0119] In embodiments, the amount of the amino substituted silane may be in a range of from about 40 mol% to about 90 mol%. The amount of the amino substituted silane may be at least about 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 or 90 mol%. In other embodiments or examples, the amount of the amino substituted silane may be less than or equal to about 90, 85, 80, 75, 70, 65, 60, 55, 50, 45, or 40 mol%. Combinations of these values to form various ranges are also possible, for example the amount of amino substituted silane may have a mol% value of between about 40 mol% to about 80 mol%, about 40 mol% to about 70 mol%, for example about 50 mol% to about 80 mol%.

[0120] Substituted silicate

[0121] A substituted silicate may be included in the metalloxerogel matrix and may produce complex structures with unique properties relevant to the resulting metalloxerogel. The substituted silicate may be according to Formula 2:

[0122] Si(OR7)4

[0123] Formula 2 wherein:

[0124] R7is Ci-ealkyl.

[0125] In some embodiments or examples, the substituted silicate may comprise a Ci- ealkyl which may be provided by any alkyl as described above or herein having a 1 to 6 atom chain.

[0126] The alkyl groups of the substituted silicate may comprise between 1 and 6 carbon atoms. The alkyl groups may be methyl, ethyl, propyl, n-butyl, t-butyl or other higher carbon alkyl groups. The substituted silicate of the present disclosure may be selected from a tetraalkoxy silane. For example, the substituted silicate may be tetramethyl orthosilicate, tetraethyl orthosilicate (TEOS), or combinations thereof.

[0127] In some embodiments or examples, the amount of substituted silicate may be in a range between about 0 mol% to about 40 mol% based on the total metalloxerogel. The amount of substituted silicate may be at least about 0, 5, 10, 15, 20, 25, 30, 35, or 40 mol%. The amount of substituted silicate may be less than or equal to about 40, 35, 30, 25, 20, 15, 10 or 5 mol%. Combinations of these amounts are possible, for example the amount of substituted silicate may be between about 10 mol% to about 40 mol%, between about 15 mol% to about 30 mol%, or between about 20 mol% to about 40 mol%. The mol% of silicate will be less than the mol% of the amino silane when forming a metalloxerogel reaction product, as described herein. The ratio of amino silane: silicate in the metalloxerogel is 1 :0-0.7. Metal ions and Metal Salts

[0128] The metalloxerogel may comprise one or more metal ions bonded within a crosslinked metal-silicate sol gel network. In some embodiments, the one or more metal ions may be selected from alkali metal ions, alkaline earth metal ions, transition metal ions, post-transition metal ions, or a combination thereof. Alkali metal ions may include ionic forms of lithium, sodium, potassium, rubidium, caesium or francium. Alkaline earth metal ions may include ionic forms of beryllium, magnesium, calcium, strontium, barium or radium, or a combination thereof. The transition metal ions may include group 3 to group 12 transition metal ions, period 4 transition metal ions, such as ionic forms of scandium, titanium, vanadium, chromium, iron, cobalt, nickel, copper or zinc, or a combination thereof, period 5 transition metal ions, such as ionic forms of yttrium, zirconium, niobium, molybdenum, technetium, ruthenium, rhodium, palladium, silver or cadmium, or a combination thereof, period 6 transition metal ions, such as ionic forms of lutetium, hafnium, tantalum, tungsten, rhenium, osmium, iridium, platinum, gold, or mercury, or a combination thereof. The post-transition metal ions may include ionic forms of aluminium, gallium, indium, thallium, tin, lead, bismuth, polonium or astatine, or a combination thereof. In an embodiment, the one or more metal ions may be selected from ionic forms of magnesium, vanadium, iron, cobalt, copper, zinc, rhodium, palladium, silver, platinum, gold and aluminium, or a combination thereof. For example, the one or more metal ions may be selected from ionic forms of magnesium, calcium, titanium, vanadium, chromium, iron, cobalt, copper, zinc, and aluminium, or a combination thereof.

[0129] A metal salt is a chemical compound consisting of an ionic assembly of positively charged cations and negatively charged anions. The positively charged cation can be any of the metal ions as discussed above. A person of skill in the art would be able to determine suitable counter anions for the chosen metal ions, including inorganic and organic counterions. The negatively charged anions may include but are not limited to acetate, chloride, fluoride, bromide, iodide, citrate, nitrate, gluconate, carbonate, sulfate, hydroxide, and oxide. In some embodiments or examples, when the metal ion is calcium (II), the metal salt may be a calcium(II) salt, such as calcium sulfate, calcium chloride, or calcium phosphate.

[0130] In some embodiments or examples, when the metal ion is magnesium (II), the metal salt may be a magnesium(II) salt, such as magnesium sulfate, magnesium chloride, magnesium bromide, magnesium iodide, magnesium nitrate, magnesium acetate or magnesium citrate.

[0131] In some embodiments or examples, when the metal ion is an ionic form of vanadium, the metal salt may be a vanadium(III), a vanadium(IV) or vanadium(V) salt, such as vanadium oxide sulfate, vanadium oxide, vanadium chloride and vanadium sulfate.

[0132] In some embodiments or examples, when the metal ion is an ionic form of chromium, the metal salt may be a chromium(II) salt or a chromium(III) salt, such as chromium nitrate, chromium acetate or chromium sulfate.

[0133] In some embodiments or examples, when the metal ion is an ionic form of iron, the metal salt may be an iron(II) salt or iron(III) salt, such as iron sulfate, iron chloride, iron nitrate and iron acetate.

[0134] In some embodiments or examples, when the metal ion is an ionic form of cobalt, the metal salt may be a cobalt(II) salt, such as cobalt sulfate, cobalt chloride, cobalt nitrate or cobalt acetate.

[0135] In some embodiments or examples, when the metal ion is an ionic form of nickel, the metal salt may be a nickel(II) salt, such as nickel sulfate, nickel chloride, nickel nitrate or nickel acetate.

[0136] In some embodiments or examples, when the metal ion is an ionic form of copper, the metal salt may be a copper(II) salt, such as copper sulfate, copper chloride, copper nitrate or copper acetate.

[0137] In some embodiments or examples, when the metal ion is zinc(II), the metal salt may be a zinc(II) salt, such as zinc sulfate, zinc chloride, zinc nitrate or zinc acetate.

[0138] In some embodiments or examples, when the metal ion is aluminium (III), the metal salt may be an aluminium(III) salt, such as aluminium sulfate, aluminium chloride, aluminium nitrate or aluminium acetate. In some embodiments or examples, when the metal ion is an ionic form of silver, the metal salt may be a silver(I) salt, such as silver nitrate or silver fluoride.

[0139] In embodiments, the one or more metal ions may have a % loading of at least 10, 20, 25, 30, 35, 40, 45, 50 mol%. In embodiments, the one or more metal ions may have a % loading of in between about 10 mol% to about 50 mol%, or between about 20 mol% to about 50 mol%, or between about 30 mol% to about 50 mol%, or between about 40 mol% to about 50 mol%, or between about 20 mol% to about 40 mol%, or between about 30 mol% to about 40 mol%. In embodiments, the one or more metal ions may have a % loading of less than or equal to 50, 45, 40, 35, 30, 25, 20 or 10 mol%.

[0140] Without wishing to be bound by theory, it is hypothesised that the amino groups of the amino substituted silane unit coordinate or bind to the metal ions. It may be therefore beneficial to express the metal ion loading as ratio between amino substituted silane and metal ions. In embodiments, the ratio of amino substituted silane to metal ion may be between 1 :0.2-1.

[0141] In embodiments, the ratio of amino substituted silane to metal ion may be selected from 1 :0.2, 1 :0.25, 1 :0.33, 1 :0.4, 1:0.5, 1 :0.66, 1 :0.75, 1 :0.8, 1 :0.9, or 1 : 1. Combinations of these values to form various ranges are also possible, for example, the ratio of amino substituted silane to metal ion may be in a range between 1 :0.2 and 1 : 1, or expressed as a range selected from any two of the listed values.

[0142] In embodiments, the ratio of substituted silicate to metal ion may be selected from 0: 1, 0.1 : 1, 0.2: 1, 0.3: 1, 0.5: 1, or 0.7:1. Combinations of these values to form various ranges are also possible, for example, the ratio of substituted silicate to metal ion may be in a range between 0:1 and 0.6: 1, or expressed as a range selected from any two of the listed values.

[0143] In embodiments, the ratio of amino substituted silane to substituted silicate may be selected from 1 :0.7, 1 :0.6, 1 :0.5, 1 :0.4, 1 :0.3, 1 :0.2, 1 :0.1, or 1 :0. Combinations of these values to form various ranges are also possible. The ratio of amino substituted silane to substituted silicate may be in a range between 1 :0-0.7.

[0144] In embodiments, the ratio of amino substituted silane to metal ion to substituted silicate may be selected from 1 :0.2:0, 1 :0.2:0.1, 1 :0.3:0.2, 1 :0.5:0.3, 1 :0.6:0.4, 1 :0.7:0.5, or 1 :1 :0.6. Combinations of these values to form various ranges are also possible. The ratio of amino substituted silane to metal ion to substituted silicate may be in a range between 1 :0.2-l :0-0.7.

[0145] Form

[0146] The metalloxerogel of the present disclosure can also be made into a composite, for use in gas adsorption, absorption, or storage, by mixing a dry or wet composition of the metalloxerogel with one or more additives, optionally a lubricant, optionally a buffer, and optionally a solvent. The one or more additives may be selected from a binder, optionally a metal organic framework (MOF), and a nanoparticle. The additive may be in an amount of about 5 to about 35 wt. % based on the total weight of the metalloxerogel. In some embodiments or examples, the composite may be self- supporting in the form of a pellet, bead, sheet or granule. In other embodiment, the composite may be applied as a coating composition, paste or film on a substrate.

[0147] The nanoparticles may be selected from the group comprising carbon-based nanoparticles (e.g. fullerenes and carbon nanotubes), metal-based nanoparticles (e.g. alkali and noble metals), ceramic nanoparticles, polymeric nanoparticles, lipid-based nanoparticles, quantum dots, silica nanoparticles, graphene, or combinations thereof. The nano-magnetic particles may be selected from the group comprising iron oxides, ferrite, or combinations thereof. The binders may be selected from the group comprising cellulose-based polymers, silane-based polymers, cellulose-siloxane-based polymers, polyglycol-based polymers, epoxy-based polymers, colloidal silica, polyvinyl pyrrolidone, polyvinyl alcohol, polyethylene imine, or combinations thereof. The binders may be selected from commercial binders. It will be appreciated that other components may form part of the commercial binder. In an example, the binders may include other components such as a lubricant. A lubricating agent may be used as required to adjust the viscosity of the aerogel formulation to, for example, an extrudable material. For example, the other components may include dicalcium phosphate, silicon dioxide, dextrose monohydrate and magnesium stearate. The buffers may be selected from the group comprising (NFL^CCh, NH4CH3CO2, NH3, NH4HCO3, carbon dioxide. Gas capture from gaseous streams or an atmosphere

[0148] The metalloxerogel of the present disclosure can be used to capture gases from gaseous streams or an atmosphere. It has been surprisingly found that the incorporation of certain metal ions allows capture of a target gas from gaseous streams or an atmosphere. Hence, the composition of the metalloxerogel can be precisely tailored in order to capture the desired target gas from a gaseous stream or an atmosphere. It has been surprisingly found that not only the selection of the metal ion but also the optimisation of the amino substituted silane to metal ion ratio can allow for effective and efficient gas capture.

[0149] In embodiments, the gas may be selected from the group comprising or consisting of ammonia (NH3), carbon monoxide (CO), oxygen (O2), ethylene oxide (EO), nitrogen oxides (NOX), hydrogen (H2), water (H2O), hydrogen fluoride (HF).

[0150] The metalloxerogels described herein may be tailored to selectively capture a wide range of gases depending on the choice of metal ion incorporated into the metalloxerogel matrix. It has been found that specific metal ions confer affinity toward particular gases, enabling targeted gas capture applications, for example, Cu(I) may be effective for CO capture; Fe(IEIII), Zn(II), and Ag(I) for NO; Fe(II / III) and Zn(II) for NO2; Cu(I), Cu(II), or Zn(II) for NH3; Cu(I), Cu(II), Co(II), or Fe(II) for O2; and Cu(I), Cu(II), Zn(II), or Fe(II / III) for toxic industrial chemical gases such as EO, IL, or HF, as shown in Table 1 :

[0151] Table 1

[0152] _ Metals _ Gas _

[0153] Cu(I) carbon monoxide (CO)

[0154] Fe (II / III), Zn(II), and Ag(I) NO

[0155] Fe(II / III), Zn(II) NO2most metals Water (H2O)

[0156] Cu(I), Cu(II), Zn(II) ammonia (NH3)

[0157] Cu(I), Cu(II), Co(II), Fe(II) oxygen (O2)

[0158] Toxic Industrial Chemicals

[0159] Cu(I), Cu(II), Zn(II), Fe(II / III) _ (TICs) _

[0160] In embodiments, when the metal ion is copper(II) or a mixed metal comprising copper(II), the metalloxerogel may be used to capture ammonia gas (NH3) and / or oxygen (O2) from a a gaseous stream and / or the atmosphere. In an embodiment, when the metal ion is copper(II) or a mixed metal comprising copper(II), the metalloxerogel may be used to capture ammonia gas (NFF) from a gaseous stream or an atmosphere. In another embodiment, when the metal ion is copper(II) or a mixed metal comprising copper(II), the metalloxerogel may be used to capture oxygen (O2) from a gaseous stream or an atmosphere. The isotherms presented in Figures 1, 2 and 3 demonstrate ammonia absorption at 20 °C. It has been surprisingly found that equilibrium ammonia absorption increases with ammonia pressure, and the amount of ammonia absorbed increases with the copper concentration. It can be seen that the increase in ammonia absorption reaches its maximum (A70 and B70) with minimal increases in the gas absorption upon further increase in copper (A100 or B 100). The isotherm presented in Figure 4 demonstrates oxygen absorption at 298 K. It has been found that equilibrium oxygen absorption increases with oxygen pressure, and the amount of oxygen absorbed varies with the copper concentration and oxidation state. The Cu(I)Cl A60 formulation showed the highest oxygen uptake, with CuCh A50 also performing well. CuCh A40 and Cu(I)Cl A80 displayed comparatively lower uptakes. These results may suggest that oxygen sorption is influenced by both copper concentration and oxidation state.

[0161] In embodiments, when the metal ion is zinc(II) or a mixed metal comprising Zn(II), the metalloxerogel may be used to capture ammonia gas (NH3) from a a gaseous stream or an atmosphere.

[0162] One or more advantages of the present disclosure according to at least some embodiments or examples as described herein is that the metalloxerogels may be designed to be highly selective to a gas of interest. For example, the earth’s atmosphere is composed of about 78% nitrogen (N2) and 21% oxygen (O2) and 1% other gases. It has been surprisingly found that the metalloxerogels of the present disclosure have O2 selectively. For example, the metalloxerogels may selectively absorb oxygen (O2) over nitrogen (N2). In an embodiment, the metalloxerogels may absorb O2 from a gaseous stream or atmosphere in environments with a O2 concentration of less than about 21 vol. %.

[0163] Similarly, ammonia (NH3) can be found mixed with nitrogen (N2) and carbon dioxide (CO2). It has been surprisingly found that the metalloxerogels of the present disclosure have NH3 selectivity. For example, the metalloxerogels may selectively absorb ammonia (NH3) over nitrogen (N2) and carbon dioxide (CO2).

[0164] The gaseous stream or atmosphere is contacted with the metalloxerogel. The gaseous stream may have a suitable flow rate to contact (e.g. pass through) the metalloxerogel. Alternatively, the gaseous stream may come into contact with the metalloxerogel without any back pressure or flow rate being applied (e.g. the gaseous stream may organically diffuse into the metalloxerogels upon contact). In some embodiments or examples, the gaseous stream may be an atmosphere surrounding the metalloxerogels. In some embodiments, the gaseous stream passes through the metalloxerogel (e.g. enters from a first side or face on the metalloxerogel and exits from different side or face). In one embodiment, the gaseous stream (e.g. atmosphere) diffuses into the metalloxerogel upon contact with the metalloxerogel.

[0165] In some embodiments or examples, the low concentration gaseous stream has an initial gas concentration prior to contacting the metalloxerogel and has a final gas concentration after contacting the metalloxerogel (also referred to herein as an effluent gaseous stream and / or effluent gas concentration). It will be appreciated that as the gas is absorbed into the metalloxerogel from the gaseous stream, the concentration of the gas in the effluent stream will be lower than the initial gas concentration of the gaseous stream prior to contact (e.g. passing through) with the metalloxerogel.

[0166] The concentration of the gas in the gaseous stream can be measured by any suitable means, for example gas chromatography-mass spectroscopy, isotopic analyser (e.g. using a G2201-i Isotopic Analyzer (PICARRO) and / or infrared spectrometer (e.g. an in-line calibrated cavity ring-down IR spectrometer).

[0167] Adsorption / absorption apparatus

[0168] In some embodiments or examples, there is provided an adsorption or gas absorption apparatus for capturing a gas from a gaseous stream or atmosphere comprising: a chamber enclosing at least one metalloxerogel, as described herein, the chamber comprising an inlet through which a gaseous stream can flow to the metalloxerogel and an outlet through which the effluent gaseous stream can flow out from the metalloxerogel. The at least one metalloxerogel may be located between the inlet and outlet of the chamber. The gases are as described above.

[0169] It will be appreciated that the metalloxerogel formulation for any given application may be chosen based on density of the metalloxerogel. The metalloxerogel formulations with high densities may be suitable for any device. For example, metalloxerogel formulations with high density can be used to prepare adsorptiondesorption devices that fit into restricted spaces or environments. These types of devices can be typically used in space, aerospace, underwater vehicles or platforms. Whereas metalloxerogel formulations with low density may be more suitable when space is not an issue.

[0170] The adsorption apparatus of the present disclosure is advantageously compact and can be located much closer to end users, thereby allowing disruptive supply opportunities and better customer value.

[0171] Processes for gas capture / release and regeneration of metalloxerogels

[0172] The gas may be captured from the gaseous stream by being adsorbed or absorbed into a metalloxerogel. In some embodiments or examples, the metalloxerogel may be capable of adsorbing or absorbing between about 10 mg of the gas per g of metalloxerogel (mg / g) to about 300 mg / g. In some embodiments or examples, the metalloxerogel may be capable of absorbing at least about 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 150, 200, 250 or 300 mg / g of the gas. In other embodiments or examples, the metalloxerogel may be capable of adsorbing or absorbing less than about 300, 250, 200, 150, 120, 100, 90, 80, 70, 60, 50, 40, 30, 20 or 10 mg / g of the gas. Combinations of these adsorption or absorption values are possible, for example the metalloxerogel may be capable of adsorbing or absorbing between about 10 mg / g to about 80 mg / g, between about 20 mg / g to about 70 mg / g, or between about 100 mg / g to about 300 mg / g, or between about 200 mg / g to about 300 mg / g of the gas. For example, the metalloxerogel may be capable of adsorbing or absorbing about 2 mg / g at 0.02 mbar to about 100 mg / g at 1110 mbar (at 298K).

[0173] In some embodiments, at least about 50% of the gas may be removed from the gaseous stream (e.g. at least about 50% of the gas is adsorption or absorbed into the metalloxerogel from the gaseous stream). In some embodiments or examples, at least about 50%, 85%, 90%, 95%, 99% or 99.9% of the gas is removed from the gaseous stream. In some embodiments, between about 50% to about 99% of the gas is removed from the gaseous stream.

[0174] As described above, before contact with the metalloxerogel, the gaseous stream has an initial gas concentration. After contact with the metalloxerogel, the effluent gaseous stream has an effluent gas concentration. The concentration of the gas in the effluent gaseous stream following contact with the metalloxerogel may be measured to determine the concentration of the gas remaining in the gaseous stream.

[0175] The concentration of a gas in the effluent gaseous stream may be measured by any suitable means, for example using an in-line calibrated cavity ring-down IR spectrometer.

[0176] The adsorption or absorption processes as disclosed herein may be conducted at ambient temperatures, for example ranging from about 10 to 40°C. For example, ambient temperature may be between 15 and 30°C, or 20 to 25°C. The processes may be conducted generally around typical atmospheric pressures (e.g. between about 20 and 100 kPa) or at low pressures (e.g. between about 0.01 and 0.05 kPa).

[0177] In one embodiment, the metalloxerogel may be regenerated by desorbing an adsorbed gas by methods known in the art. The desorbed metalloxerogel may be reused to adsorb and desorb a selective gas as required. An advantage of the metalloxerogel, as described herein, may be their ability to be used multiple times in adsorption - desorption cycles to selectively capture a gas, which can be used for industrial purposes.

[0178] It will be appreciated by persons skilled in the art that numerous variations and / or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive. EXAMPLES

[0179] In order that the disclosure may be more clearly understood, particular embodiments of the invention are described in further detail below by reference to the following non-limiting experimental materials, methodologies and examples.

[0180] Example 1: Preparation of Metalloxerogels

[0181] The metalloxerogels were prepared using (i) at least one amino substituted silane and a metal ion that can form complexes with these amines, or (ii) at least one amino substituted silane, at least one substituted silicate, and a metal ion that can form complexes with these amines. The amino substituted silane and the substituted silicate presented in the examples below are 3 -aminopropyl(di ethoxy )methylsilane (APEMS) and tetraethyl orthosilicate (TEOS). It will be appreciated that the methods described below can be used with other amino silanes according to Formula 1 and substituted silicates according to Formula 2, as described herein. for example, three metalloxerogel series A, B and C are prepared as shown below in Table 2.

[0182] Table 2. Ratio of APEMS to TEOS

[0183] To the silane solution, the aqueous metal salt solution is added to form covalent crosslinked aerogel material with interconnecting metal-amine bonds. The metal ion content can be varied as described below. Most of these materials must be made in a single reaction step (Method 1); however, Series A can be made in a two-step process (Method 2) as polymers made of APEMS alone do not form a gel in the absence of the metal.

[0184] For simplicity, the examples below use CuCE, however, any metal ion that binds to primary amines can be used interchangeably. Method 1. One step method for Series A, B and C.

[0185] Metalloxerogel Series A - CuCh

[0186] Two solutions were made, Solution 1 containing the silanes dissolved in ethanol, and Solution 2 containing the metal salt dissolved in water.

[0187] Solution 1 : 1 mol / L (191.34g / L) of 3-Aminopropyl(diethoxy)methylsilane (APEMS) was dissolved in ethanol by stirring.

[0188] Solution 2: A IM CuCh (134.45g / L) solution was combined with water as described in Table 3.

[0189] Table 3. Solution 2 for synthesis of Series A metalloxerogels.

[0190] Then 100 mL of Solution 1 was combined with 100 mL of Solution 2 and the mixture was stirred overnight at room temperature producing a solid product. The solid produced was filtered, and then taken up into 200 mL of water, stirred and refiltered. The filtered product was dried at 80°C to form a powder.

[0191] Metalloxerogel Series B - CuCh

[0192] Solution 1 : 0.8 mol / L (153.07g / L) of 3-Aminopropyl(diethoxy)methylsilane (APEMS) and 0.2 mol / L tetraethyl orthosilicate (TEOS) (41.67g / L) were combined in ethanol and stirred until uniform.

[0193] Solution 2: A IM CuCh (134.45g / L) solution was combined with water as described in Table 4. Table 4. Solution 2 for synthesis of Series B metalloxerogels.

[0194] Then 100 mL of Solution 1 was combined with 100 mL of Solution 2 and the mixture was stirred overnight at room temperature producing a solid product. The solid produced was filtered, and then taken up into 200 mL of water, stirred and refiltered. The filtered product was dried at 80°C to form a powder.

[0195] Metalloxerogel Series C - C11CI2

[0196] Solution 1 : 0.6mol / L (114.80g / L) of 3-Aminopropyl(diethoxy)methylsilane (APEMS) and tetraethyl orthosilicate (TEOS) 0.4mol / L (83.33g / L) were combined in ethanol and stirred until uniform.

[0197] Solution 2: A IM CuCh (134.45g / L) solution was combined with water as described in Table 5.

[0198] Table 5. Solution 2 for synthesis of Series C metalloxerogels.

[0199] Then 100 mL of Solution 1 was combined with 100 mL of Solution 2 and the mixture was stirred overnight at room temperature producing a solid product. The solid produced was filtered, and then taken up into 200 mL of water, stirred and refiltered. The filtered product was dried at 80°C to form a powder.

[0200] Method 2. Two step method for Series A

[0201] As the polymer of APEMS does not form any crosslinks in the absence of TEOS or metal ions, the synthesis of the Series A metalloxerogels can be split into two steps. This is nearly identical to the method above, with a small quantity of water being added to the Solution (1) and allowing it to stir overnight, before the aqueous salt solution is added. This method is less sensitive to acidic metal ions, with the materials made this way being nearly identical to the single step method.

[0202] Metalloxerogel Series A - C11CI2

[0203] Step T. Solution 1 was prepared by combining 1 mol / L (191.34g / L) of 3- Aminopropyl(di ethoxy )methylsilane (APEMS) in ethanol with 1.5 moles (27g / L) of water, and allow to stir overnight. Solution 2 was made by combining IM CuCh (134.45g / L) solution with water as described in Table 6.

[0204] Table 6. Solution 2 for synthesis of Series A metalloxerogels.

[0205] Step 2: 103 mL of Solution 1 was combined with 100 mL of Solution 2 and the mixture was stirred overnight at room temperature producing a solid product. The solid produced was filtered, and then taken up into 200 mL of water, stirred and refiltered. The filtered product was dried at 80°C to form a powder. Metalloxerogel Series A - Cu(I)Cl

[0206] Step T. Solution 1 was prepared by combining 1 mol / L (191.34g / L) of 3- Aminopropyl(diethoxy)methylsilane (APEMS) in ethanol with 1.5 moles (27g / L) of water, and allow to stir overnight.

[0207] Step 2 Given poor solubility of CuCl in water, Solution 2 was prepared by slowly adding powdered Cu(I)Cl with vigorous stirring to lOOmL of Solution 1 (i.e. 100 mmoles of APEMS), as shown in Table 7. The metalloxerogel precipitated and was then filtered and washed with water.

[0208] Table 7. Solution 2 for synthesis of Cu(I)Cl metalloxerogels.

[0209] CuCl(s)

[0210] Metalloxerogel (mmoles)

[0211] A20 20

[0212] A30 30

[0213] A40 40

[0214] A50 50

[0215] A60 60

[0216] A70 70

[0217] A80 80

[0218] A90 90

[0219] A100 100

[0220] Divalent species Mg, Co, Cu and Zn easily formed products for A-10 through A-100 and all of B and C series, with metal ions of higher valences (such Al(III), V(III) and Fe(III)) forming metalloxerogels easily with series B and C, more specifically with B20-B40 and C20-C40.

[0221] Example 2: Dynamic gas Capture Performance

[0222] Breakthrough experiments will be performed on a custom rig consisting of Mass flow controllers with humidity control, Swagelok stainless steel tubing, a glass column with sintered frit and an IR spectrometer. 1.5 g to 3.0 g of Activated metalloxerogel will be loaded into the glass column and packed down while a glass wool filter is placed on top of the material. The Mass flow controllers will be set to the desired flow rate. The gas, such as ammonia, carbon dioxide or carbon monoxide, will be flowed through the Mass flow controller at a concentration of 1000 ppm to 10,000 ppm and the output through the column will be directly measured into the detector of an IR spectrometer.

[0223] The experiment will reach its endpoint when the IR spectrometer reached a level of 25 ppm of gas.

Claims

1. CLAIMS:

1. A metalloxerogel comprising one or more metal ions bonded within a crosslinked metal-silicate sol gel network comprising a plurality of pores, wherein the metalloxerogel is a reaction product comprising at least one amino substituted silane according to Formula 1 and at least one metal salt, wherein Formula 1 is:R1Si(OR2)2-L-NH2Formula 1 wherein:R1is a substituted or unsubstituted Ci-ealkyl;R2is Ci-ealkyl;L is a -Ci-ealkyl- linker group between the silicon and nitrogen atoms; and wherein: the metalloxerogel is selective for gas capture, and the ratio of amino substituted silane to metal ion is between 1 :0.2-1.

2. The metalloxerogel according to claim 1, wherein the reaction product further comprises at least one substituted silicate.

3. The metalloxerogel according to claim 1 or claim 2, wherein the ratio of amino substituted silane to metal ion to substituted silicate is between L0.2-L0-0.7.

4. The metalloxerogel according to any one of the preceding claims, wherein the one or more metal ions is selected from ionic forms of an alkali metal, an alkaline earth metal, a transition metal or a post-transition metal, or a combination thereof.

5. The metalloxerogel according to any one of the preceding claims, wherein the one or more metal ions is selected from the group consisting of ionic forms of Ca, Mg, V, Cr, Fe, Co, Ni, Cu, Zn, Al and Ag, or a combination thereof.

6. The metalloxerogel according to any one of the preceding claims, wherein the one or more metal ions has a % loading of at least 20 mol%.

7. The metalloxerogel according to any one of the preceding claims, wherein the one or more metal ions has a % loading between about 10 mol% to about 50 mol%.

8. The metalloxerogel according to any one of the preceding claims, wherein the amount of the one or more metal ions is effective for facilitating gas capture.

9. The metalloxerogel according to any one of the preceding claims, wherein the amino substituted silane has a % loading of between about 40 mol% to about 90 mol%.

10. The metalloxerogel according to any one of claims 2 to claim 9, wherein the substituted silicate has a % loading of between about 0 mol% to about 40 mol%.

11. The metalloxerogel according to any one of the preceding claims, wherein the at least one amino substituted silane is 3-aminopropyl (diethoxy) methyl silane (APEMS).

12. The metalloxerogel according to any one of claims 2 to 11, wherein the at least one substituted silicate is according to Formula 2:Si(OR7)4Formula 2 wherein:R7is Ci-ealkyl.

13. The metalloxerogel according to any one of claims 2 to 12, wherein the at least one substituted silicate is tetraethoxy silane (TEOS).

14. The metalloxerogel of any one of the preceding claims, wherein at least 50 % of the pores are mesoporous (as measured by N2 gas adsorption isotherms, performed at 77K).

15. A process for preparing a metalloxerogel according to any one of claims 1 to 14, the process comprising:(i) mixing an aqueous solution comprising at least one metal salt together with a solvent system comprising at least one amino substituted silane according to Formula 1 and optionally at least one substituted silicate according to Formula 2, optionally one or more additives, to form a wet-gel matrix comprising the one or more metal ions bonded within a cross-linked metal-silicate sol gel network comprising amine groups; and(ii) drying the wet-gel matrix to provide a dried metalloxerogel; with the proviso that drying the wet-gel matrix does not involve supercritical CO2.

16. A process for preparing a metalloxerogel according to claim 15, the process comprising:(i) mixing an aqueous solution comprising at least one metal salt together with a solvent system comprising at least one amino substituted silane according to Formula 1 and at least one substituted silicate according to Formula 2, optionally one or more additives, to form a wet-gel matrix comprising the one or more metal ions bonded within a cross-linked metal-silicate sol gel network comprising amine groups; and(ii) drying the wet-gel matrix to provide a dried metalloxerogel; with the proviso that drying the wet-gel matrix does not involve supercritical CO2.

17. The process according to claim 15 or 16, wherein the process is a sol gel process and step (ii) comprises:(al) optionally heating the wet-gel matrix to obtain a gel; and(a2) drying the gel by solvent evaporation and / or heat treatment to provide a dried metalloxerogel.

18. A method for capturing a gas from a gaseous stream or atmosphere containing the gas comprising:contacting the gaseous stream or atmosphere with the metalloxerogel according to any one of claims 1 to 14 for capturing at least some of the gas from the gaseous stream or atmosphere.

19. The method according to claim 18, wherein the gas is selected from the group consisting of ammonia (NH3), carbon monoxide (CO), oxygen (O2), ethylene oxide (EO), nitrogen oxides (NOX), hydrogen (H2), water (H2O), and hydrogen fluoride (HF).

20. The method according to claim 19, wherein (i) the gas is ammonia (NH3) and / or oxygen (O2) and the metalloxerogel is a copper based metalloxerogel; (ii) the gas is oxygen (O2) and the metalloxerogel is a copper based metalloxerogel; or (iii) the gas is ammonia (NH3) and the metalloxerogel is a zinc based metalloxerogel.

21. The method according to any one of claims 18 to 20, wherein the gaseous stream or atmosphere has a gas concentration of less than about 10,000 ppm and / or at least about 50% to 99% of the gas is removed from the gaseous stream or atmosphere.

Images