Solid material having multiple open voids, including geopolymers and solid particles, and method for producing the same.

Abstract

The present invention relates to a solid material having open, multiple, and at least partially interconnected porosity, comprising an inorganic matrix made from microporous and mesoporous geopolymers, defining at least partially interconnected open macropores bounded by sides or walls made from the microporous and mesoporous geopolymers, and containing particles of at least one solid compound different from the geopolymer distributed within the macropores and / or sides or walls. Methods for preparing the material are also disclosed. The present invention also relates to a method for separating at least one metal or metalloid cation from a liquid medium containing it, wherein the liquid medium is placed in contact with the material.

Description

[Technical Field]

[0001] The present invention relates to a solid material having multiple open voids, also known as a material having hierarchical open voids, which includes a geopolymer and solid particles distributed within the voids.

[0002] More specifically, the present invention relates to a solid material having multiple open voids, comprising a mineral, inorganic matrix made from microporous and mesoporous geopolymers, wherein at least partially interconnected open macropores are defined, defined by sides or walls made from microporous and mesoporous inorganic geopolymers, and particles of at least one distinct and separate solid compound, different from the geopolymer, are distributed in the macropores and / or sides or walls.

[0003] The Matrix is ​​also referred to as the "skeleton."

[0004] The particles may be active particles, particularly inorganic solid metal cation exchange compounds, adsorbent particles, or catalyst particles.

[0005] The material according to the present invention may be in the form of a monolith in particular.

[0006] The present invention also relates to a method for preparing the said material.

[0007] The present invention may be applied to numerous fields, such as catalysts, metal cation separation, or extraction on a solid phase by integrating particles of selective adsorbents such as zeolites.

[0008] More specifically, the present invention may be applied to the field of treating spills, particularly liquid spills, and especially to treating radioactive liquid spills, with a particular aim of removing metal cations, such as strontium cations, from them.

[0009] Accordingly, the present invention also relates to a method for separating metal cations, particularly radioactive or toxic metal cations, contained in a medium, particularly a liquid medium, using the aforementioned materials. [Background technology]

[0010] Methods using fixed beds require the development of materials with multiple voids to optimize the transport properties for the target ions or molecules, and which are large enough to act as a bed while minimizing head loss as much as possible. These materials with multiple voids are particularly macroporous materials, which contain active sites consisting of nanometer, submicron, or micron-sized active particles within their voids.

[0011] The preparation of these porous materials containing nanometer, submicron, or micron-sized active particles in their voids may be carried out by granulation from nanometer, submicron, or micron-sized active particles and an inorganic binder obtained elsewhere, according to the first method.

[0012] Next, the entire mixture is cold-compressed, and the binder imparts cohesive force to the powder mixture. The binder is used in a dry state in the direct compression method, or in an aqueous medium in the wet granulation method. In the wet granulation method, active particles in the nanometer, submicron, or micron range are suspended with the binder to ensure cohesive force, and are usually followed by extrusion molding or heat treatment, such as drying or sintering. The most frequently used inorganic binders are clay-based. This method is industrial and simple. This method is also applicable to any type of particle. However, with this method, it is impossible to obtain a controlled porosity of the material, resulting in poor transport properties (hydrodynamic and diffusion properties) for fixed-bed applications. In addition, the "tablets" thus obtained have low mechanical strength (Patent Document 1).

[0013] The preparation of these porous materials, which contain active particles on the nanometer, submicron, or micron scale within their voids, may be carried out by the second method by converting other porous materials, such as silica gel, porous glass, or porous silica obtained by a sol-gel process.

[0014] This second method involves having a substrate, appropriately controlling its porosity, and subjecting it to chemical treatment in order to obtain the required properties of active particles in the nanometer, submicron, or micron range (Non-Patent Documents 1 and 2).

[0015] This method is difficult to replace for all types of active particles because each type of particle has a different composition and therefore requires specific processing. The method is complex and requires several steps, making it difficult to replace industrially. Furthermore, this method can cause void clogging, resulting in poor access to the active site.

[0016] The preparation of these porous materials containing nanometer, submicron, or micron-sized active particles within their voids may be carried out by a third method, which involves functionalizing the porous material. This method consists of pre-functionalizing a porous material that acts as a "framework," and then gradually growing the active material on the framework structure from the pre-functionalized graft (Patent Document 2 and Non-Patent Document 3).

[0017] In this case as well, this method is complex, requires several steps, and is difficult to substitute with any type of particle. This method can also cause pore clogging.

[0018] The preparation of these porous materials containing nanometer, submicron, or micron-sized active particles in their voids may be carried out by impregnating a substrate porous material with a suspension containing nanometer, submicron, or micron-sized active particles according to the fourth method (Patent Documents 3 and 4).

[0019] This method is easy to implement but requires several impregnation steps. In these impregnation steps, on the one hand, clogging of the pores of the substrate porous material occurs, and on the other hand, it is difficult to completely control the amount of particles inserted into the substrate or the uniformity of the insertion of particles into the pore network, so the management is complicated. Finally, poor adhesion of the particles to the substrate may be observed, which can induce the release of active particles during the use of the material in a fixed bed effluent treatment operation. Furthermore, this type of synthesis can result in materials with low mechanical strength (Patent Document 3).

[0020] The preparation of these porous materials containing active particles in nanometer, submicron or micron units may be carried out according to a fifth method using a water-in-oil emulsion containing active particles in nanometer or submicron units, and the emulsion is stabilized by the presence of a surfactant, or active particles (pickering emulsion), or a combination of these two. The inorganic oxide precursor in the aqueous phase makes it possible to add cohesive force to the mixture by forming a skeleton when the oil phase is extracted (Patent Documents 5 and Patent Document 6). This method involves a sol-gel type synthesis that requires the skeleton to be made of an oxide (mainly using silica), is complicated to control, uses relatively expensive precursors (alkoxides), and is difficult to industrialize.

[0021] Furthermore, this method is limited to the insertion of active particles of small size (up to several hundred nm), and the synthesis may be very difficult for some categories of active particles and may be difficult to manage industrially.

[0022] Finally, in the alveolar porous structure of the obtained material, good hydrodynamic transport characteristics for fixed bed applications are not obtained, and potentially, the access of the treated effluent to some of the active particles incorporated into the material skeleton becomes difficult.

[0023] Therefore, from the above points, for materials having multiple voids, especially for materials having interconnected macrovoids that are mechanically strong and can uniformly incorporate active particles, there are still unmet requirements. These active particles need to be easily accessible to the effluent circulating within the macrovoids and have a higher accessibility than at least the materials of the prior art.

[0024] There is also a need for materials that can have a wide variety of shapes and sizes, for example, sizes ranging from millimeters to tens of centimeters.

Prior Art Documents

Patent Documents

[0025]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Non-Patent Documents

[0026]

Non-Patent Document 1

[0027] A first objective of the present invention is, in particular, to address the requirements for such materials.

[0028] The object of the present invention is to provide a material that does not have the drawbacks, limitations, and disadvantages of prior art materials, particularly the materials described in the prior art documents cited above, and that solves the problems of these materials.

[0029] Furthermore, there is a need for a material preparation method that is reliable, involves a limited number of steps, is versatile, and can be adapted to all kinds of active particles, regardless of their properties and size (e.g., nanometer, micron, or submicron units). In particular, this method must be reproducible and easy to implement so that it can be easily adapted to an industrial scale.

[0030] A second object of the present invention is, in particular, to satisfy the requirements for such a method. [Means for solving the problem]

[0031] The first and other objectives described above are achieved, according to the present invention, by a solid material comprising an (inorganic) matrix made of microporous and mesoporous geopolymers, which is open, multiple, and has at least partially interconnected voids. In the matrix, open macropores that are at least partially interconnected are defined, separated by sides (surfaces, fronts) or walls made of microporous and mesoporous geopolymers, and particles of at least one separate solid compound different from the geopolymers are distributed within the macropores and / or sides or walls.

[0032] The terms “geopolymer” or “geopolymer matrix or skeleton” within the scope of the present invention refer to a dry, solid porous material obtained after curing of a mixture containing a finely ground material (i.e., generally an aluminosilicate source) and a salt solution (i.e., an activating solution), wherein the mixture is a porous material capable of setting and curing over time. This mixture is also called a “geopolymer mixture,” “geopolymer composition,” or “geopolymer paste.” The curing of the geopolymer is the result of the dissolution / polycondensation of the finely ground material of the geopolymer mixture in a salt solution, such as a high-pH salt solution (i.e., an activating solution).

[0033] More specifically, the geopolymer, geopolymer matrix, or backbone is an amorphous aluminosilicate inorganic polymer. The polymer is obtained from a reactive material that essentially contains silica and aluminum (i.e., aluminosilicate source), is activated by a strongly alkaline solution (activating solution), and has a low solid / solution mass ratio in the formulation. The structure of the geopolymer consists of a Si-O-Al lattice formed of tetrahedra in which silicate (SiO4) and aluminate (AlO4) are bonded at their vertices by oxygen atom sharing. Within this lattice, AlO4 - There exists one or more charge-compensating cations, also known as compensating cations, which enable the compensation of the negative charge of the complex. The compensating cations are advantageously selected from the group consisting of alkali metals, such as lithium (Li), sodium (Na), potassium (K), rubidium (Rb), and cesium (Cs), alkaline earth metals, such as magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba), and mixtures thereof.

[0034] According to the present invention, the geopolymers defined above are macroporous, mesoporous, and macroporous, and generally have a density of 1.5 g / cm³. 3 Less than 1.2 g / cm³, especially 1.2 g / cm³. 3 Less than 0.9 g / cm³ 3 Less than, more specifically, 0.6 g / cm³ 3 It has a density of less than 1.

[0035] The term "macroporous geopolymer" refers to a geopolymer having macropores, the term "mesoporous geopolymer" refers to a geopolymer having mesopores, and the term "microporous geopolymer" refers to a geopolymer having micropores.

[0036] According to the present invention, the term "macropore" refers to a pore with an average size greater than 500 Å, which is generally defined by the diameter of the cross-section (since pores generally have a circular cross-section); the term "mesopore" refers to a pore with an average size of 20 to 500 Å; and the term "micropore" refers to a pore with an average size of less than 20 Å, for example, 5 to 10 Å. Note that 1 nm = 10 Å.

[0037] Mesovoids typically account for 20–33% by volume of the total voids in geopolymers.

[0038] The geopolymer forming the framework and matrix of the material according to the present invention also includes macropores defined within the framework and matrix.

[0039] Macrovoids typically account for 20–80% by volume of the total voids in geopolymers.

[0040] Voids can be measured by nitrogen adsorption-desorption or mercury intrusion.

[0041] Microvoids typically account for less than 15% by volume, especially less than 10% by volume, and particularly 5-10% by volume, relative to the total voids of the geopolymer.

[0042] In geopolymers, the total voids, corresponding to macrovoids, mesovoids, and microvoids, account for more than 70% by volume, particularly more than 75% by volume, and especially more than 80% by volume, relative to the total volume of the geopolymer.

[0043] The material according to the present invention is an open, multilayered solid material having voids that are at least partially or even entirely interconnected (i.e., macro voids, micro voids, and meso voids), and is also referred to as a hierarchically open material having voids that are at least partially or entirely interconnected.

[0044] More precisely, the material according to the present invention has open and connected (or interconnected) voids.

[0045] According to the present invention, this void is multilayered, that is, it simultaneously includes macro voids, micro voids, and meso voids.

[0046] These voids are also open, meaning they are accessible to fluids such as effluents positioned to come into contact with the material. These voids are also at least partially connected (interconnected), or even fully interconnected, meaning fluids can pass through the material via interconnected pores. These voids also allow access to particles.

[0047] The concept of open voids applies to all pore sizes in materials, namely macropores, micropores, and mesopores. Pores (macropores, micropores, and mesopores) are open, and regardless of pore size, they are all at least partially connected, interconnected with one another, or even completely connected and interconnected with one another.

[0048] Therefore, macropores may be interconnected and connected to mesopores and / or micropores, mesopores may be interconnected and connected to micropores and / or macropores, and micropores may be interconnected and connected to macropores and / or mesopores.

[0049] The opening and interconnection of macropores are not solely caused by the presence of micropores and mesopores. Two macropores can also be interconnected.

[0050] In summary, the interconnection of macropores is independent of the presence of mesopores and micropores.

[0051] Surprisingly, the presence of particles, particularly active particles, in the material according to the present invention significantly enhanced the interconnection of macropores compared to the same material without particles. Furthermore, it was observed that the material according to the present invention, unlike the same material without particles, does not contain partially closed alveolar macropores (see Examples).

[0052] Advantageously, the geopolymer used within the scope of the present invention has percolating macropores that connect a first main surface of the geopolymer material to a second main surface of the material.

[0053] According to the present invention, the term "main surface" refers to the outer portion of the material that defines the edge of the material to the surrounding environment. The main surface typically has cavities, particularly unoccluded cavities visible to the naked eye.

[0054] The material according to the present invention has a specific structure not described or suggested in the prior art, and further comprises a specific material, namely, a geopolymer that constitutes the skeleton which is the matrix of the material according to the present invention.

[0055] The material according to the present invention further comprises particles of at least one solid compound different from the geopolymer, such as active particles, which are accessible within the matrix.

[0056] According to the present invention, in addition to the mere presence of particles of at least one solid compound different from the geopolymer, such as active particles, it is important that the properties and size of the particles of at least one solid compound different from the geopolymer can be selected, as they are substantially boundaryless and independent of the geopolymer matrix.

[0057] In fact, the material according to the present invention can first be defined as a material having multiple or hierarchical voids, or a material having voids of different scales, more specifically three scales, comprising a matrix or framework defined by microporous and mesoporous sides (surfaces, fronts) or walls, with at least partially interconnected open macropores (in other words, open, at least partially interconnected macrovoids). Thus, the material according to the present invention includes combinations of macrovoids, mesovoids, and microvoids. Furthermore, in the material according to the present invention, the macropores are open and at least partially interconnected, or even completely interconnected, and do not have a purely alveolar structure, which is surprisingly due to the presence of particles of at least one solid compound different from geopolymers in the material according to the present invention.

[0058] In the material according to the present invention, open and interconnected macropores enable the transport of fluids such as effluents in the material, and when these particles are located inside the walls and sides of the macropores, the open and interconnected mesopores and micropores themselves ensure that particles of at least one solid compound different from the geopolymer can easily access them.

[0059] In other words, the interconnectivity between multiple voids and macropores allows for a highly favorable optimization of fluid transport, such as effluent, and accessibility to particles within the material.

[0060] It should be noted that good interconnection can result in good accessibility for particles of at least one solid compound distinct from the geopolymer, but this is not systematic. Therefore, while substantial interconnection of macropores is possible, the particles become completely embedded in the walls and sides, resulting in agglomeration. If the walls and sides are neither mesoporous nor microporous, then these particles will be inaccessible, and the material will be unsatisfactory. In the material according to the present invention, good accessibility for particles is always obtained thanks to open and interconnected micropores and mesopores, and especially macropores.

[0061] The mechanical strength of the material according to the present invention is ensured by a mechanically very strong geopolymer backbone (generally an aluminosilicate).

[0062] In general, geopolymer matrices have many advantages over metal oxide matrices.

[0063] The synthesis of geopolymers is easier to control than the synthesis of metal oxides by sol-gel processes.

[0064] The synthesis of geopolymers requires less expensive precursors than those used to synthesize metal oxides (primarily alkoxides).

[0065] Geopolymer matrices possess superior mechanical strength compared to metal oxide matrices.

[0066] Geopolymer matrices contain mesopores, while metal oxide matrices do not. Creating mesopores in metal oxides requires the addition of additional compounds to the emulsion formulation, thus complicating the system.

[0067] In conclusion, the material according to the present invention has hierarchical voids, is mechanically robust, and, in particular, due to the existing interconnectivity between macropores, incorporates particles, generally active particles (for example, for specific applications in the context of processing fluids such as liquid or gaseous effluents), providing enhanced accessibility of the fluid, such as the effluent being processed, to the particles distributed within the material.

[0068] In other words, the material according to the present invention has open and interconnected macropores into which particles of at least one solid compound different from the geopolymer are inserted, and these particles are accessible.

[0069] Advantageously, the material according to the present invention may be in the form of particles such as granules, granules, or beads (in this case, these particles are not particles of at least one separate solid compound different from the geopolymer), or in the form of a monolith.

[0070] The material particles or monoliths may have sizes ranging from 300 microns (μm) to 10 or tens of centimeters, for example, 10, 10, 30, 40, 50, or even 100 centimeters (generally defined by their maximum dimensions, e.g., their diameter).

[0071] Therefore, the term size generally refers to the maximum dimensions of a material particle or monolith.

[0072] Sizes of 300-500 microns are particularly suitable for use in fixed-bed systems with column packing.

[0073] According to the present invention, the term monolith means a solid object having an average size of at least 1 mm.

[0074] Advantageously, the particles of at least one solid compound different from the geopolymer may have an average size, for example, a diameter of 2 nm to 100 μm, preferably 10 nm to 10 μm.

[0075] The term "size" also in this specification means the maximum dimension, e.g., diameter, of particles of at least one solid compound distinct from the geopolymer.

[0076] The particle size of at least one solid compound distinct from the geopolymer may be selected for a specific target application.

[0077] Advantageously, the particles of at least one solid compound different from the geopolymer may be selected from the group consisting of nanometer particles, submicron particles, and micron particles.

[0078] According to the present invention, the term "nanometer particle" means a particle whose average size, generally defined by its diameter, is 2 to 100 nm; the term "submicron particle" means a particle whose average size, generally defined by its diameter, is 100 nm to 1 μm; and the term "micron particle" means a particle whose average size, generally defined by its diameter, is 1 to 100 μm.

[0079] The particles of at least one solid compound different from the geopolymer may be entirely inorganic mineral particles, i.e., particles consisting of only one or more inorganic solid compounds (100%).

[0080] The particles of at least one solid compound distinct from the geopolymer may be partially organic particles, i.e., particles comprising one or more inorganic solid particles and one or more organic solid compounds, which is particularly true for "MOF" particles (see below).

[0081] Advantageously, the particles of at least one solid compound different from the geopolymer may be particles of an active compound, or simply active particles.

[0082] The term "active particles" or particles of an active compound generally refers to particles that can act in chemical, physical, or physicochemical processes such as chemical reactions, sorption phenomena, and catalytic processes, particularly for the treatment of liquid or gaseous effluents, such as catalysis or extraction, in contrast to inactive particles.

[0083] Preferably, these active particles are selected from the group consisting of particles of at least one solid metal cation exchange compound, catalyst particles, and adsorbent compound particles.

[0084] Advantageously, the solid metal cation exchange compound may be selected from the group consisting of zeolites, alkaline silicate salts, coordination polymer (metal-organic structure) particles, and mixtures thereof.

[0085] There are no restrictions on the shape of particles of at least one solid compound different from geopolymers.

[0086] Advantageously, the particles of at least one solid compound different from the geopolymer may have a spherical or ellipsoidal shape, or a needle-like shape.

[0087] Advantageously, the content of particles of at least one solid compound different from the geopolymer is 0.1 to 30% by mass, preferably 5 to 15% by mass, relative to the total mass of the material.

[0088] According to the present invention, the second objective described above is achieved by the method for preparing materials according to the present invention described above.

[0089] This preparation method involves at least the following sequential steps: a) A step of preparing an oil-in-water emulsion formed from droplets of an oil phase dispersed in a continuous aqueous phase by mechanical stirring with shearing of a mixture comprising an oil phase and an aqueous phase, wherein the aqueous phase comprises an activating solution, an aluminosilicate source capable of forming a geopolymer by dissolution / polycondensation (of the aluminosilicate source in the activating solution), and optionally a surfactant, and at least one particle of a solid compound (different from the geopolymer) is present at the interface formed by the droplets of the oil phase dispersed in the continuous aqueous phase of the emulsion, b) A step of allowing the emulsion to stand, forming and shaping it to obtain a selected size and shape, and forming a geopolymer matrix by polycondensation, c) A step of obtaining the material according to the present invention by removing the oil phase. Includes.

[0090] Advantageously, the emulsion is formed and molded within a mold of a selected size and shape.

[0091] The method according to the present invention includes a specific sequence of specific steps that have not been described or suggested in the prior art cited above.

[0092] The method according to the present invention enables the synthesis and preparation of materials according to the present invention, namely materials having hierarchical voids, being mechanically robust, and incorporating particles, particularly active particles (e.g., active particles having specific applications in the context of treating liquid or gaseous effluents), thereby providing enhanced accessibility of the particles to fluids such as the effluent being treated.

[0093] The method according to the present invention makes it possible to synthesize the material in a controlled shape and size, for example, in the range of 1 millimeter to several tens of centimeters (see above), without requiring a post-synthesis grinding or compression step.

[0094] In particular, it is important to note that the method according to the present invention enables the synthesis of materials without imposing any restrictions on the size and shape of the materials.

[0095] Therefore, for example, the only thing that limits the size of the final material formed, i.e., the object made of the material, is the size of the mold that can be used in step b).

[0096] The method according to the present invention is characterized in particular by the use of reagents required for the synthesis of geopolymer-based inorganic binders in a continuous phase of an emulsion containing particles of at least one solid compound different from the geopolymer, such as active particles.

[0097] According to the present invention, the emulsion preparation method is optimized to enable better interconnectivity between macropores of the geopolymer backbone, and therefore to provide better access for the fluid circulating in the material to the active particles.

[0098] According to the present invention, an emulsion having an aqueous activated solution of a geopolymer as a continuous phase is stabilized in a novel and unexpected way using a protocol comprising particles of at least one solid compound different from the geopolymer, such as active particles and optionally a surfactant, and at least one sequence, such as two homogenization sequences.

[0099] The latter two parameters (i.e., stabilization using a protocol that includes particles and optionally a surfactant, as well as at least one homogenization sequence) enable the formation of pores, particularly macropores that are non-alveolar, better interconnected, and allow better access to the active particles.

[0100] In other words, in the method according to the present invention, in step a), an oil-in-water emulsion is prepared, more specifically an oil phase dispersed in a continuous aqueous phase, the aqueous phase comprising an activating solution and an aluminosilicate source capable of forming a geopolymer by dissolution / polycondensation. The emulsion is stabilized in the presence of particles of at least one solid compound different from the geopolymer, particularly the activating particles. It may also be necessary to add a surfactant that can act synergistically with the particles to stabilize the emulsion.

[0101] By controlling the parameters of this emulsion, particularly the size of the oil droplets, it becomes possible to control the final voids in the material through control of different processes (including processes a3) and a4) described below).

[0102] By inserting an aluminosilicate source, it becomes possible to obtain a geopolymer-type inorganic binder in the aqueous phase of an emulsion through a dissolution / polycondensation process.

[0103] The emulsion prepared in step a) generally contains 40% to 80% by volume, preferably 50% to 60% by volume, of the oil phase relative to the total volume of the emulsion.

[0104] The concentration of solid particles in the emulsion may be 0.05% to 20% by mass, preferably 1% to 10% by mass.

[0105] The oil phase of a mixture generally consists of one or more oils. The term "oil" is well known and widely used by those skilled in the art.

[0106] The method according to the present invention can be appropriately carried out with any type of oil.

[0107] Advantageously, the oil phase of the mixture generally consists of one or more linear or branched alkanes having 7 to 22 carbon atoms, preferably 12 to 16 carbon atoms, such as dodecane and hexadecane.

[0108] Preferably, the oil phase of the mixture consists of dodecane.

[0109] The mechanical stirring carried out in step a) is mechanical stirring accompanied by shearing.

[0110] Advantageously, the shear rate may be 1,000 to 20,000 rpm, preferably 2,000 to 15,000 rpm, and a more preferable shear rate may be 10,000 rpm.

[0111] The size of the macrovoids in the material may be controlled by acting on the shear rate of the emulsion. As the shear rate increases, the size of the macrovoids decreases.

[0112] The mechanical stirring with shearing performed in step a) (mechanical stirring performed together with shearing) may be carried out in different ways, each of which allows for the acquisition of specific pores. In practice, higher shearing rates promote the formation of smaller macropores compared to lower shearing rates. Therefore, the shearing of the emulsion may be mechanical shearing using a homogenizer or ultrasonic shearing using ultrasound.

[0113] Preferably, the mechanical stirring with shearing carried out in step a) is performed using an emulsifying apparatus, such as an Ultraturrax® dispersion-homogenization apparatus. Step a) can be described as the step of emulsifying the above mixture.

[0114] In other words, the term mechanical stirring with shear generally refers to mechanical stirring using a stirring device equipped with an impeller rod, or preferably a homogenizing or dispersion device (e.g., Ultra-Turrax, IKA® type) which can be equipped with a dispersion rod having a rotor / stator system.

[0115] As already identified above, advantageously, the shear rate set by the homogenization or dispersion device may be 1,000 to 20,000 rpm, preferably 2,000 to 15,000 rpm, and a more preferable shear rate may be 10,000 rpm.

[0116] The expressions "aluminosilicate source" and "reagent material essentially containing silica and aluminum" are similar and can be used interchangeably in this invention.

[0117] The reagent materials essentially containing silica and aluminum that can be used to prepare the geopolymer matrix of the material according to the present invention are, advantageously, solid sources containing amorphous aluminosilicates. These aluminosilicates are selected in particular from natural aluminosilicate minerals such as illite, stilbite, kaolinite, pyrophyllite, andalusite, bentonite, kyanite, milanite, grovenite, amesite, cordierite, feldspar, and allophane, calcined natural aluminosilicate minerals such as metakaolin, synthetic glass based on pure aluminosilicate, alumina cement, pumice, calcined by-products or residues from industrial processes such as fly ash or blast furnace slag obtained when iron ore is converted into cast iron in a blast furnace, respectively, and mixtures thereof.

[0118] The term "activating solution" refers to a high-pH sodium chloride solution, which is well known in the field of geopolymer formation. The latter is a strongly alkaline aqueous solution that may optionally contain a silicate compound particularly selected from the group consisting of silica, colloidal silica, and quartz glass.

[0119] The terms "activating solution," "high pH salt solution," and "strongly alkaline solution" are similar and can be used interchangeably in this invention.

[0120] The terms "strongly alkaline" or "high pH" refer to a solution with a pH greater than 9, especially greater than 10, particularly greater than 11, and more specifically greater than 12. In other words, the activated solution is of a pH greater than 0.01 M, especially greater than 0.1 M, particularly greater than 1 M, and more specifically 5-20 M of OH - It has a concentration.

[0121] The activating solution contains the above-mentioned compensating cation or a mixture of compensating cations in the form of an ionic solution or a salt. Therefore, the activating solution is particularly selected from aqueous solutions of sodium silicate (Na2SiO3), potassium silicate (K2SiO2), sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca(OH)2), cesium hydroxide (CsOH), and derivatives thereof.

[0122] In step b), the emulsion is left to stand and allowed to stand so that the geopolymer skeleton can be formed by polycondensation in the continuous phase of the emulsion.

[0123] During this standing and settling process, the size and shape of the final material are determined by the processability of the synthetic emulsion. Therefore, monoliths, beads, or granules are obtained according to the processability of the emulsion.

[0124] The term "workability" refers to the ability of an emulsion to be formed and molded (for example, using a mold) at a specific time interval before it hardens and forms the final material, that is, while the emulsion still has a liquid or gelled appearance before it hardens and forms the material.

[0125] This step can be carried out by leaving the emulsion obtained in step b) at a temperature of 10 to 60°C, for example 40°C, for a sufficient time for the material according to the present invention to form. This time may be, for example, 2 hours to 3 weeks, for example 24 hours to 7 days.

[0126] In step c), the oil phase still present in the pores of the material is removed.

[0127] The oil phase can be removed by any technique known to those skilled in the art.

[0128] The oil phase can be removed, in particular, by washing in a Soxhlet extractor, followed by drying, treatment with a supercritical fluid such as supercritical CO2, hydrothermal treatment, heat treatment, or a combination of these different treatments.

[0129] Washing can remove organic residues from the oil phase, and these organic residues are basically located within the macropores.

[0130] This cleaning can be carried out with an organic solvent, such as THF, acetone, or a mixture thereof, such as a THF-acetone mixture, preferably a 50-50 mixture of THF and acetone.

[0131] This cleaning may be carried out over a period of 12 to 36 hours, for example, 24 hours.

[0132] Preferably, this washing is carried out by refluxing an organic solvent.

[0133] Drying can be carried out by evaporating the organic solvent used for washing at room temperature over a period of time typically 5 to 10 days, for example, 7 days.

[0134] Alternatively, drying may be carried out by heating to a temperature of, for example, 90°C.

[0135] Drying may be carried out using a supercritical fluid such as supercritical CO2.

[0136] In the method according to the present invention, a macroporous material (where macro voids are generated by the oil phase), which is a material according to the present invention, i.e., a material used particularly for stabilizing emulsions (but also for the desired applications of the material), preferably active particles, in particular nanometer, submicron, or micron particles, is obtained with the synergistic assistance of an optional surfactant. The voids, mechanical strength (conferred by the geopolymer backbone of the material), shape and size of the material, and the properties and size of the active particles are therefore controlled simultaneously.

[0137] This method is easy to implement and can be easily replaced industrially.

[0138] For the purpose of summary, the advantages and unexpected effects of the method according to the present invention, with respect to the manufacture and preparation of materials according to the present invention, namely materials having multiple voids containing active particles, are listed below, in particular. Some of these advantages of the method of the present invention are advantages related to the materials that can be obtained by this method and are substantially already described above.

[0139] The interconnectivity between multiple voids and macropores can be fully controlled by controlling the emulsion (especially the size of the oil droplets), thereby optimizing the transport characteristics of fluids such as effluents within the material, and the accessibility of the fluid to active particles.

[0140] • Mesovoids and microvoids in the geopolymer matrix ensure increased access to active particles that can be incorporated into the sides and wall cores of the material's macropores.

[0141] • The mechanical strength of the final material is ensured by a robust aluminosilicate geopolymer backbone.

[0142] It is very important to note that the method according to the present invention can be carried out with any type of particles, especially active particles, regardless of the properties, size, particularly 2 nm to 100 μm, preferably 10 nm to 10 μm, and particle size distribution (which may be nanometers, submicrons, or even microns).

[0143] To achieve this, all that is needed is to adjust the parameters to obtain and stabilize the starting emulsion.

[0144] The size of the active site directly corresponds to the size (nanometers, submicrons, or microns) of particles incorporated into the material formulation according to the present invention, which can be obtained elsewhere.

[0145] • The size of the resulting molded final material is entirely modular and depends, for example, on the mold used in step b).

[0146] The method according to the present invention is carried out under mild conditions, at low temperatures, generally at room temperature and atmospheric pressure. The method according to the present invention uses inexpensive and non-toxic reagents, particularly for the activating solution and aluminosilicate source. The reaction medium is basically aqueous.

[0147] The method according to the present invention is simple, reliable, easy to implement, and uses inexpensive and readily available reagents. The method according to the present invention can be carried out with simple equipment and apparatus. In particular, the method according to the present invention is one in which all steps (including steps a3 and a4 below) can be carried out in a single reactor. In other words, the method according to the present invention may be described as a "one-pot" method.

[0148] Therefore, if the vessel and reactor used to generate the emulsion in step a) are later used as a mold in steps b) and c), step b) can be carried out in a single reactor and vessel, which is the same reactor used in step a).

[0149] The method according to the present invention can be easily implemented on an industrial scale.

[0150] Advantageously, prior to step a), the following sub-steps a1) to a4) are taken to prepare a mixture containing the oil phase and the aqueous phase. a1) A step of preparing an aqueous solution of particles of at least one solid compound (different from the geopolymer), preferably active particles, in water or an aqueous solution containing a surfactant, a2) Adding an oil phase to the aqueous suspension of particles obtained at the end of step a1), thereby obtaining a two-phase mixture containing an aqueous phase consisting of an oil phase and an aqueous suspension, and a3) Adding an aqueous activating solution (alkali silicate) to the aqueous phase of the two-phase mixture obtained at the end of step a2), a4) A step of adding an aluminosilicate source capable of forming a geopolymer by dissolution / polycondensation to the aqueous phase of the two-phase mixture obtained at the end of step a3) and This will be executed.

[0151] Generally, the aqueous suspension of particles prepared in step a1) has a particle concentration of 2 g / L to 1000 g / L.

[0152] The particle concentration in the suspension is selected according to the final concentration of particles of at least one solid compound different from the geopolymer, which is desired in the prepared material.

[0153] The surfactant may be selected from anionic, cationic, nonionic surfactants, or mixtures thereof. An example of a surfactant is tetradecyltrimethylammonium bromide (TTAB).

[0154] In the aqueous suspension prepared in step a1), the surfactant concentration is generally 0.1% to 20% by mass relative to the mass of the particles.

[0155] Advantageously, after step a2) and before step a3), the two-phase mixture comprising an oil phase and an aqueous phase consisting of an aqueous suspension is subjected to mechanical stirring with shearing, and / or after step a3) and before step a4), the two-phase mixture is subjected to mechanical stirring with shearing.

[0156] This mechanical stirring, involving shearing, has already been described in detail above.

[0157] The present invention also relates to the use of materials according to the present invention for catalyzing chemical reactions, filtering fluids, or separating or extracting substances contained in fluids. The fluid may be in any physical state, and may be in particular a liquid or gaseous state.

[0158] The material according to the present invention may, in particular, be used in a method for separating, not exclusively, at least one metal cation or metalloid cation from a liquid medium containing it, wherein the liquid medium is placed in contact with the material according to the present invention.

[0159] This medium may be a liquid or a gaseous medium.

[0160] The material according to the present invention is particularly suitable for such applications due to its excellent properties, such as excellent exchange capacity, excellent selectivity, and high reaction rate.

[0161] This excellent effect can be obtained with a small amount of active particles, such as particles of inorganic solid metal cation exchange compounds like zeolites.

[0162] In addition, the excellent mechanical strength and mechanical stability properties of the material according to the present invention, resulting from its specific structure, enable the continuous implementation of conditioning and separation methods within a column, and thus can be easily incorporated into existing equipment, for example, in a processing chain or line involving multiple steps.

[0163] Advantageously, the liquid medium may be an aqueous liquid medium such as an aqueous solution.

[0164] The liquid medium may be a treatment liquid or industrial waste liquid.

[0165] Advantageously, the liquid medium may be selected from liquids and effluents obtained from the nuclear industry and facilities and operations using radionuclides.

[0166] Generally, the cation may be present at a concentration of 0.1 picogram to 500 mg / L, preferably 0.1 picogram to 100 mg / L.

[0167] The term "metal" also encompasses isotopes of the metal, particularly radioactive isotopes, and the term "metalloid" also encompasses isotopes of the metalloid, particularly radioactive isotopes.

[0168] Advantageously, the cation may be a cation of an element selected from alkali metals, alkaline earth metals, transition metals, heavy metals, rare earths (scandium, yttrium and lanthanides), actinides, noble gases, and their isotopes, particularly their radioactive isotopes.

[0169] Zeolites are particularly suitable for the separation of such cations.

[0170] For example, the cation may be a cation of an element selected from Sr, Cs, Co, Ag, Ru, Fe and Tl and their isotopes, particularly their radioactive isotopes.

[0171] In particular, the cation is 134 Cs, or 137 Cs, or 90 a cation of Sr.

[0172] This method has all the advantages inherent in the materials according to the invention used in the method and has already been described above.

[0173] Hereinafter, the present invention will be described in more detail, particularly with specific embodiments which are the subject of the examples. [Brief explanation of the drawing]

[0174] [Figure 1] This figure shows images obtained by scanning electron microscopy (SEM) of submicron particles of zeolite LTA prepared in Example 1. The scale applied to Figure 1 is 1 μm. [Figure 2] This figure shows a photograph of a monolith containing a geopolymer incorporating submicron particles of zeolite LTA prepared in Example 1 using Protocol P0. [Figure 3A] This figure shows an SEM image of the inside of the monolith prepared in Example 1. The scale applied to Figure 3A is 70 μm. [Figure 3B] This figure shows an SEM image of the inside of the monolith prepared in Example 1A. The scale applied to Figure 3B is 70 μm. [Figure 4] This graph shows the pore size distribution of two geopolymers: a pure synthetic geopolymer (Example 1B) (Curve A), a geopolymer synthesized with zeolite using P0 (Example 1) (Curve B), and a geopolymer synthesized with P0 without zeolite (Example 1A) (Curve C). The x-axis represents pore size (unit: nm), and the y-axis represents dV / dlog(D) pore volume (unit: cm3 / g·nm). [Figure 5] This graph shows the diffraction patterns of submicron zeolite LTA (curve A), zeolite-free geopolymer synthesized with P0 (Example 1A) (curve B), and geopolymer containing zeolite LTA synthesized with P0 (Example 1) (curve C). The x-axis represents 2θ (unit: °), and the y-axis represents intensity (arbitrary unit). [Figure 6A] This figure shows an SEM image of the geopolymer monolith prepared in Example 2 according to Protocol P1. The scale applied to Figure 6A is 70 μm. [Figure 6B] This figure shows an SEM image of the geopolymer monolith prepared in Example 2 according to Protocol P2. The scale applied to Figure 6B is 70 μm. [Figure 6C]This figure shows an SEM image of the geopolymer monolith prepared in Example 2 according to Protocol P3. The scale applied to Figure 6C is 70 μm. [Figure 7] This graph shows the pore size distribution in the monoliths prepared in Example 2 according to protocols P1, P2, and P3. The x-axis represents pore size (unit: nm), and the y-axis represents dV / dlog(D) pore volume (unit: cm3 / g·nm). [Figure 8] This bar graph shows the Kd (unit: mL / g) values ​​(Example 3) determined for geopolymer zeolites (without submicron zeolite particles) prepared according to protocol P0 and geopolymer monoliths (with zeolite particles) prepared according to protocols P0, P1, P2, and P3. [Figure 9] This figure shows an SEM image of the micron zeolite particles used in Example 4. The scale applied to Figure 9 is 5 μm. [Figure 10] This graph shows the diffraction patterns (Example 4B) of micron particles of zeolite 4A (curve A), a geopolymer without zeolite 4A particles prepared according to protocol P3 (curve B), and a geopolymer containing zeolite 4A particles prepared according to protocol P3 (curve C). The x-axis represents 2θ (unit: °), and the y-axis represents intensity (arbitrary unit). [Figure 11] This graph shows the particle size distribution analysis of the nanometer particles of CST used in Example 5. The x-axis represents size (in μm), and the y-axis represents percentage (in numbers). [Figure 12] This graph shows the diffraction patterns of CST nanoparticles (curve A), a CST-free geopolymer prepared according to protocol P3 (curve B), and a geopolymer containing CST nanoparticles prepared according to protocol P3 (curve C) (Example 5B). [Figure 13] This graph shows the nitrogen adsorption isotherms generated for pure geopolymers. The x-axis represents relative pressure (P / P°), and the y-axis represents nitrogen adsorption amount (unit: cm³ / g). [Modes for carrying out the invention]

[0175] The present invention will be described below with reference to the following examples, which are for illustrative purposes only and not intended to be limiting. [Examples]

[0176] (Example 1) In this embodiment, the production of a monolithic material containing a submicron zeolite-incorporated geopolymer according to the present invention is carried out.

[0177] More precisely, in this embodiment, submicron particles of zeolite LTA (known as an efficient and selective adsorbent of Sr in aqueous media) according to the present invention are incorporated into a macroporous geopolymer matrix, i.e., a "framework".

[0178] • Synthesis of submicron particles of zeolite LTA The protocol for synthesizing submicron particles of zeolite LTA is as follows: - Dissolve 2.65 g of NaOH pellets (sold by Sigma-Aldrich®) and 5.75 g of NaAlO2 powder (sold by VWR®) separately in 26.25 mL and 35 mL of water, respectively. Next, the two solutions are mixed in an autoclave while being vigorously stirred for several minutes. Next, 2 g of SiO2 powder (Aerosil® 380, available from Evonik Industries®) is added to the autoclave, and the autoclave is hermetically sealed. - Heat treatment is performed at 40°C for 20 hours, followed by 70°C for 24 hours. - The resulting powder is finally collected by filtration, washed with water, and dried overnight at 80°C.

[0179] Submicron particles of zeolite LTA with a size of 300-500 nm are ultimately obtained (see Figure 1).

[0180] • Manufacturing of materials in the form of monoliths containing geopolymers incorporating submicron particles of zeolite LTA. The protocol for synthesizing a material containing a geopolymer incorporating the above-mentioned synthesized zeolite LTA submicron particles is protocol P0, which first includes the following sequence of steps. - Step 1: 617 mg of zeolite LTA powder (consisting of submicron particles) is dissolved in a surfactant, namely tetradecyltrimethylammonium bromide (TTAB) (sold by Sigma-Aldrich®) at a concentration of 34.8 g / L. -1 It was added to 1.774 mL of concentrated aqueous solution. The concentrated aqueous solution with the powder added was placed in an ultrasonic bath for 15 minutes. - Step 2: Next, add 5 mL of oil phase, i.e., dodecane (sold by Sigma-Aldrich®), to the concentrated aqueous solution to which the powder has been added. - Step 3: Add 2.12 mL of a solution based on an aqueous solution of modified potassium silicate, consisting of 81% by mass of a commercially available inorganic binder called Betol® K5020T (available from Wollner®), and composed of 30% by mass of SiO2, 18% by mass of K2O, 52% by mass of H2O, and 19% by mass of KOH (85%, sold by Sigma-Aldrich®). - Step 4: Add 2.64g of metakaolin powder (BASF Metamax®). - So-called "UT" process 5: The mixture is finally sheared for 1 minute at a shearing rate of 10,000 rpm using an Ultra-Turrax® homogenizer equipped with an S25N-18G dispersion head.

[0181] In this way, an emulsion is obtained at the end of step 5.

[0182] This viscous emulsion was placed in a cylindrical mold with a diameter of 1 cm and left to stand for 48 hours.

[0183] After demolding, a solid monolithic cylindrical material with a height of approximately 4 cm and a diameter of 1 cm is obtained.

[0184] Next, the monolithic material is washed in a Soxhlet extractor with a 50-50 THF-acetone mixture to remove dodecane, and then dried at 80°C.

[0185] After 24 hours of drying, a solid and rigid monolith retaining its dimensions is obtained (Figure 2).

[0186] (Example 1A) In this example, the material is manufactured in the form of a monolith, similar to Example 1 but without submicron particles of zeolite LTA. This monolith is synthesized according to the same protocol as in Example 1, called protocol P0.

[0187] (Example 1B) In this embodiment, a pure geopolymer (pure synthetic geopolymer) is produced according to protocol P0, without submicron zeolite, without TTAB, and without adding oil to form an emulsion.

[0188] The resulting geopolymer was 71.3 m 2 ·g -1 It has a specific surface area of ​​.

[0189] (Example 1C) In this embodiment, the properties of the materials prepared in Examples 1, 1A, and 1B are determined.

[0190] The interiors of the two monoliths prepared in Example 1 and Example 1A were observed using a scanning electron microscope (SEM). The obtained images are shown in Figures 3A and 3B.

[0191] The following can be observed. - In the absence of zeolite particles, the material has alveolar pores that are unconnected (or have very few interconnections). - In the presence of zeolite, the microstructure of the material is completely different. The pores no longer have an alveolar structure, and their interconnections are strengthened.

[0192] The monoliths prepared in Examples 1 and 1A were analyzed by nitrogen adsorption-desorption to determine their specific surface area (BET model) and pore size distribution (<60 nm, BJH model). For the geopolymer containing zeolite (material of Example 1) and the geopolymer without zeolite (material of Example 1A), 34.4 and 37.8 m were obtained. 2 ·g -1 The specific surface area is measured.

[0193] Figure 4 shows the mesopore size distribution of both materials.

[0194] This figure also shows the mesopore size distribution of the pure geopolymer prepared in Example 1B.

[0195] Pure synthetic geopolymers (Example 1B) and materials prepared using protocol P0 without zeolite (Example 1A) have a pore size distribution centered around 19-20 nm, while materials synthesized using protocol P0 with zeolite (Example 1 according to the present invention) are observed to have a centered pore size of approximately 27 nm.

[0196] Therefore, the presence of zeolite in the formulation can increase the size of mesopores.

[0197] Figure 13 shows the adsorption isotherm of a pure geopolymer. This isotherm has a type IV shape according to the IUPAC classification, and the shape of the curve at low pressure indicates the presence of micropores in the geopolymer structure.

[0198] Next, the two monoliths prepared in Example 1 and Example 1A were ground into powder form and subjected to X-ray diffraction (XRD) analysis.

[0199] XRD analysis will also be performed on pure submicron zeolite LTA powder.

[0200] The results of these analyses are shown in Figure 5. (Note: Figure 5 refers to a "pure geopolymer," which is a geopolymer synthesized without submicron zeolite, without TTAB, and without adding oil to form an emulsion (the geopolymer of Example 1B).

[0201] The three diffraction patterns shown in Figure 5 demonstrate that the submicron particles of zeolite LTA are indeed incorporated into the structure of the macroporous geopolymer in the material prepared in Example 1 according to the present invention.

[0202] (Example 1D) In this example, the effectiveness of the materials prepared in Example 1 and Example 1A according to the present invention in removing strontium (Sr)-containing spills was investigated.

[0203] In other words, in this embodiment, the materials prepared in Example 1 and Example 1A according to the present invention were tested for their use as Sr adsorbent materials.

[0204] Therefore, it is possible to perform a Sr sorption test in solution to demonstrate that the zeolite LTA inserted into the geopolymer skeleton of the material prepared in Example 1 is indeed effective.

[0205] The parameter used to measure strontium sorbation is Kd (partition coefficient in mL / g units), which is calculated according to the following formula.

[0206]

number

[0207] In this formula, - [Sr] init and [Sr] fin These represent the initial and final Sr concentrations (mg / L) in the solution, respectively. - V is the volume of the solution (mL), - m is the mass (g) of the material.

[0208] The protocols used for these sorbation tests are as follows: - Add 50 mg of the material (monolithic form) to 50 mL of matrix (aqueous solution) containing 0.05 mol / L NaNO3, 50 ppm Ca (added in the form of Ca(NO3)2 salt), 2 ppm Cs (added in the form of CsNO3 salt), and 2 ppm Sr (added in the form of Sr(NO3)2 salt). - Stir the entire mixture in a rotary agitator for 24 hours. - After stirring, 15 ml of the supernatant is extracted using a syringe, and this sample is filtered through a 0.22 μm syringe filter. Subsequently, the residual Sr concentration is analyzed by inductively coupled plasma (ICP).

[0209] A geopolymer monolith without zeolite (Example 1A) has a Kd of 1128 mL / g, while a geopolymer monolith containing zeolite LTA particles (Example 1 according to the present invention) has a Kd of 5024 mL / g. These results demonstrate that zeolite LTA particles embedded in a macroporous geopolymer (Example 1 according to the present invention) enable a substantially five-fold improvement in contamination removal.

[0210] This clearly demonstrates the possibility of access to zeolite particles by contaminated spills.

[0211] (Example 2) In this embodiment, in order to investigate the effect of the manufacturing method on the macrovoids of the monolithic material, monolithic materials containing a geopolymer incorporating submicron zeolite are prepared by various methods.

[0212] Therefore, to observe the effect of the manufacturing method on the interconnectivity of macrovoids and macropores in the material, one or two additional steps, called "UT" steps, were added to different steps of Protocol P0 (referred to as steps 1, 2, 3, 4, and 5 ("UT") in Example 1).

[0213] Therefore, we tested three new protocols, called protocols P1, P2, and P3, and they are listed in Table 1 below.

[0214] The amount of added material is the same as that used in Example 1. Therefore, the final materials obtained using protocols P0, P1, P2, and P3 have exactly the same final chemical composition.

[0215] [Table 1]

[0216] It is important to note that in the specific context of Examples 1 and 2, the descriptions of protocols P0, P1, P2, P3 and P4 presented herein can be readily generalized, and in particular, the specific conditions of different processes can be readily generalized with respect to the “means for solving the problem” described above.

[0217] Regardless of the protocol used, the emulsion was systematically stabilized, then placed in a mold and left to stand for 48 hours to allow the geopolymer skeleton to set and form a cylindrical monolith several centimeters high and 1 cm in diameter.

[0218] After washing with a 50-50 THF-acetone mixture in a Soxhlet extractor for 24 hours to remove dodecane, the monolith was dried at 80°C for 24 hours.

[0219] Next, the interior of each of the obtained monoliths is observed using a scanning electron microscope (SEM).

[0220] The obtained images are shown in Figures 6A, 6B, and 6C.

[0221] The following can be observed. - Protocol P1 (Figure 6A) produces so-called "alveolar" material in which the pores appear to be slightly interconnected. - Protocol P2 (Figure 6B) generates intermediate microstructures with alveolar pore residues, as well as non-alveolar and more interconnected pores. - Protocol P3 (Figure 6C) produces mostly non-alveolar and strongly interconnected pores.

[0222] The monoliths are analyzed by nitrogen adsorption-desorption to determine their specific surface area (Brunauer, Emmett, and Teller models, "BET") and pore size distribution (<60 nm, Barrett, Joyner, and Halenda models, "BJH"). For materials prepared according to protocols P1, P2, and P3, the values ​​were 33.1, 30.6, and 31.5 nm, respectively. 2 ·g -1 Measure the specific surface area.

[0223] Figure 7 shows the pore size distribution (<60 nm) for the three materials.

[0224] The pore size distribution of each material is centered at 27 nm, similar to that obtained for materials synthesized using zeolite and P0.

[0225] Therefore, changes to the synthesis protocol do not appear to affect the mesopore size distribution.

[0226] Therefore, these results clearly demonstrate the effect of reversing the manufacturing process on the interconnectivity of macrovoids and macropores in the material, without altering the mesovoids of the walls.

[0227] These results indicate that protocol P3 is the preferred protocol, followed by protocol P0, then protocol P2, and finally protocol P1.

[0228] (Example 3) This example examines the influence of the manufacturing method on the effectiveness of decontamination of monolithic materials containing geopolymers with submicron zeolite LTA particles.

[0229] For this purpose, the effectiveness of materials prepared according to protocols P1, P2, and P3 for decontaminating strontium-containing spills was investigated.

[0230] A "batch" experiment similar to the one conducted in Example 1D was performed.

[0231] Figure 8 shows the Kd values ​​obtained for materials prepared according to protocols P1, P2, and P3.

[0232] Figure 8 also shows the Kd values ​​obtained from a zeolite-free geopolymer monolith (prepared in Example 1A according to Protocol P0) (1128 mL / g Kd, see Example 1C), and the Kd values ​​obtained from a geopolymer monolith containing zeolite LTA particles prepared according to Protocol P0 (Example 1 according to the present invention, 5024 mL / g Kd, see Example 1D).

[0233] Figure 8 shows a clear difference between Kd values. This is due to the varying internal void microstructures of the material, which allow the activated zeolite particles to access more or less of the effluent that needs to be removed.

[0234] therefore, - Materials prepared according to protocols P0 and P3 have a non-alveolar, more interconnected microstructure and a higher Kd value. - The material prepared according to protocol P1 has a highly alveolar structure with few interconnections and a Kd of only twice that of the zeolite-free material. - The material prepared according to protocol P2 has an intermediate microstructure, and therefore produces an intermediate Kd.

[0235] Here again, these results indicate that protocol P3 is the preferred protocol, followed by protocol P0, then protocol P2, and finally protocol P1.

[0236] (Example 4) In this embodiment, the production of a monolithic material containing a geopolymer incorporating micro-sized zeolite according to the present invention is carried out.

[0237] More precisely, in this embodiment, micronized particles of zeolite 4A (known as an efficient and selective adsorbent of Sr in aqueous media) according to the present invention are incorporated into a macroporous geopolymer matrix.

[0238] The micron particles of Zeolite 4A are commercially available particles manufactured by CTI (Ceramiques Techniques Industrielles).

[0239] Figure 9 shows SEM images of these particles, which are 4–5 μm in size.

[0240] Using manufacturing protocol P3 (described in Example 2), the mass of the submicron zeolite was replaced with an equal mass of micron zeolite.

[0241] Thus, a viscous emulsion is obtained at the end of the final stage of protocol P3 (step "UT").

[0242] This viscous emulsion is placed in the mold and left to stand for 48 hours.

[0243] After demolding, a monolithic material is obtained.

[0244] Next, the monolithic material is washed in a Soxhlet extractor with a 50-50 THF-acetone mixture to remove dodecane, and then dried at 80°C.

[0245] After 24 hours of drying, a cylindrical monolith with a height of several centimeters and a diameter of 1 cm is obtained.

[0246] Next, the monolith is crushed into a powder form. Then, X-ray diffraction (XRD) analysis is performed.

[0247] (Example 4A) In this example, the material is produced in the form of a monolith similar to Example 4 but without micron-sized particles of zeolite 4A. This monolith is synthesized according to the same protocol as Example 4, called Protocol P3, without including micron-sized zeolite, without including TTAB, and without adding oil to form an emulsion.

[0248] Next, the monolith is crushed into a powder form. Then, X-ray diffraction (XRD) analysis is performed.

[0249] (Example 4B) [[ID=二十]]In this example, X-ray diffraction (XRD) analysis of the powders obtained at the end of Examples 4 and 4A is performed.

[0250] XRD analysis is also performed on micron-sized zeolite 4A powder.

[0251] The results of these XRD analyses are shown in Figure 10. (Note: In Figure 10, it refers to "pure geopolymers", which are geopolymers synthesized without including micron-sized zeolite, without including TTAB, and without adding oil to form an emulsion (the geopolymers of Example 4A).

[0252] The three diffraction patterns shown in Figure 10 indicate that the micron-sized zeolite 4A particles are indeed incorporated into the structure of the macroporous geopolymers.

[0253] (Example 4C) In this example, the effectiveness of the material prepared in Example 4 according to the present invention for the removal of contamination of the effluent containing strontium (Sr) was examined.

[0254] For this purpose, a "batch" test similar to the one performed in Example 1D was conducted.

[0255] A Kd of 5528 mL / g was obtained, exceeding the Kd of 1128 mL / g for the geopolymer without active particles (see Example 1D), demonstrating the effectiveness of the material.

[0256] (Example 5) In this example, the production of a monolithic material containing a geopolymer incorporating nanometer crystalline silicate (CST) particles according to the present invention is carried out.

[0257] More precisely, in this embodiment, nanometer particles of crystalline silicate titanate (CST), known as an efficient and selective adsorbent of Sr in aqueous media, are incorporated into a macroporous geopolymer "skeleton" matrix according to the present invention.

[0258] Nanometer CST particles are commercially available particles manufactured by UOP.

[0259] Figure 11 shows the laser particle size distribution analysis of these particles, indicating that the particle size in the solution after ultrasonic dispersion is approximately 10–20 nm.

[0260] Using manufacturing protocol P3 (described in Example 2), the mass of the submicron zeolite was replaced with an equal mass of CST.

[0261] Thus, at the end of the final stage of protocol P3, a viscous emulsion is obtained (step "UT").

[0262] This viscous emulsion is placed in the mold and left to stand for 48 hours.

[0263] After demolding, a monolithic material is obtained.

[0264] Next, this monolithic material is washed in a Soxhlet extractor with a 50-50 THF-acetone mixture to remove dodecane and then dried at 80 °C.

[0265] After 24 hours of drying, a cylindrical monolith several centimeters in height and 1 cm in diameter is obtained.

[0266] Next, the monolith is ground into a powder form.

[0267] (Example 5A) In this example, a material in the form of a monolith similar to that of Example 5 but without nanometer CST particles is produced. This monolith is synthesized according to the same protocol as Example 5, called Protocol P3.

[0268] Next, the monolith is ground into a powder form.

[0269] (Example 5B) In this example, X-ray diffraction (XRD) analysis of the powders obtained at the end of Examples 5 and 5A is performed.

[0270] XRD analysis is also performed on the nanometer CST powder.

[0271] The results of these XRD analyses are shown in Figure 12. (Note: In Figure 12, reference is made to a pure diopolymer, which is a diopolymer synthesized without including CST, without including TTAB, and without adding oil to form an emulsion (the diopolymer of Example 4A).

[0272] These three diffraction patterns show that the nanometer CST particles are indeed incorporated into the structure of the macroporous diopolymer.

[0273] (Example 5C) In this example, the effectiveness of the material prepared in Example 5 according to the present invention for the removal of contamination of an effluent containing strontium (Sr) was examined.

[0274] For this purpose, a "batch" test similar to the one performed in Example 1D will be conducted.

[0275] A Kd of 4732 mL / g was obtained, exceeding the 1128 mL / g Kd of the geopolymer without active particles (see Example 1D), demonstrating the effectiveness of the material.

Claims

1. A solid material having open multiple voids and at least partially interconnected voids, comprising a matrix made of microporous and mesoporous geopolymers, wherein open macropores are defined, at least partially interconnected, separated by sides or walls made of microporous and mesoporous geopolymers, and particles of at least one solid compound different from the geopolymer are distributed within the macropores and / or sides or walls. A material comprising particles of at least one solid compound different from the aforementioned geopolymer, having an average size of 10 nm to 10 μm.

2. The material according to claim 1, which is in the form of particles or monoliths.

3. The material according to claim 1 or 2, wherein the particles of at least one solid compound different from the geopolymer are selected from the group consisting of nanometer particles, submicron particles, and micron particles.

4. The material according to any one of claims 1 to 3, wherein particles of at least one solid compound different from the geopolymer are active particles that can act in a chemical, physical, or physicochemical process.

5. The material according to claim 4, wherein the active particles are selected from the group consisting of at least one solid metal cation exchange compound particle, catalyst particle, and adsorbent compound particle.

6. The material according to claim 5, wherein the solid metal cation exchange compound is selected from the group consisting of zeolites, alkaline silicotitanates, coordination polymer (metal-organic structure) particles, and mixtures thereof.

7. The material according to any one of claims 1 to 6, wherein the amount of particles of at least one solid compound different from the geopolymer is 0.1 to 30% by mass with respect to the total mass of the material.

8. A method for preparing a material according to any one of claims 1 to 7, comprising at least the following sequential steps: a) A step of preparing an oil-in-water emulsion formed from droplets of the oil phase dispersed in a continuous aqueous phase by mechanical stirring with shearing of a mixture containing an oil phase and an aqueous phase, wherein the aqueous phase comprises an activating solution, an aluminosilicate source capable of forming a geopolymer by dissolution / polycondensation, and optionally a surfactant, and at least one solid compound particle is present at the interface formed by the droplets of the oil phase dispersed in the continuous aqueous phase of the emulsion, b) A step of allowing the emulsion to stand, forming and shaping it to obtain a selected size and shape, and forming a geopolymer matrix by polycondensation, c) A step of obtaining the material according to any one of claims 1 to 7 by removing the oil phase. Methods that include...

9. The method according to claim 8, wherein the oil phase of the mixture comprises one or more linear or branched alkanes having 7 to 22 carbon atoms.

10. Prior to step a), the following sequential sub-steps a1) to a4) are taken to prepare a mixture containing the oil phase and the aqueous phase: a1) A step of preparing an aqueous solution of particles of at least one solid compound in water or an aqueous solution containing a surfactant, a2) An oil phase is added to the aqueous suspension of particles obtained at the end of step a1), thereby obtaining a two-phase mixture containing an aqueous phase consisting of an oil phase and an aqueous suspension, and a3) A step of adding an aqueous activating solution to the aqueous phase of the two-phase mixture obtained at the end of step a2), a4) A step of adding an aluminosilicate source capable of forming a geopolymer by dissolution / polycondensation to the aqueous phase of the two-phase mixture obtained at the end of step a3) and The method according to claim 8 or 9, wherein the above is carried out.

11. The method according to claim 10, wherein, after step a2) and before step a3), a two-phase mixture comprising an oil phase and an aqueous phase comprising an aqueous suspension is subjected to mechanical stirring with shearing, and / or after step a3) and before step a4), the two-phase mixture is subjected to mechanical stirring with shearing.

12. Use of the material according to any one of claims 1 to 7 for catalyzing a chemical reaction, for filtering a fluid, or for separating or extracting a substance contained in a fluid.

13. A method for separating at least one metal cation or metalloid cation from a liquid medium containing the same, wherein the liquid medium is placed in contact with a material according to any one of claims 1 to 7.

14. The method according to claim 13, wherein the liquid medium is an aqueous liquid medium.

15. The method according to claim 13 or 14, wherein the liquid medium is selected from liquids and spills originating from the nuclear industry and facilities and operations using radionuclides.

16. The method according to any one of claims 13 to 15, wherein the cation is present at a concentration of 0.1 picograms to 500 mg / L.

17. The method according to any one of claims 13 to 16, wherein the cation is a cation of an element selected from alkali metals, alkaline earth metals, transition metals, heavy metals, rare earth elements, actinides, noble gases, and their isotopes.

18. The method according to any one of claims 13 to 17, wherein the cation is a cation of an element selected from Sr, Cs, Co, Ag, Ru, Fe, and Tl and their radioactive isotopes.

19. The aforementioned cation, 134 Cs, or 137 Cs, or 90 The method according to claim 18, wherein the cation is Sr.

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