WO2022269184A1

WO2022269184A1 - Process for producing a mof-based product and powder of grains composed of a mof-based product

Info

Publication number: WO2022269184A1
Application number: PCT/FR2022/051196
Authority: WO
Inventors: Giovanni MASSASSO; Patrick NGUYEN VAN NUOI
Original assignee: Saint-Gobain Centre De Recherche Et D'etudes Europeen
Priority date: 2021-06-21
Filing date: 2022-06-20
Publication date: 2022-12-29
Also published as: FR3124093A1

Abstract

A process for producing a MOF-based product comprises mixing raw materials to form a starting batch, said starting batch comprising a MOF powder and a polysaccharide gellable by a gelling agent, the mass ratio of the amount of said polysaccharide to the total amount of said polysaccharide and of the MOF powder or powders in said mixture being not less than 0.1% and not more than 10%, shaping said starting batch by a technique selected from extrusion, strip casting and screen-printing, to give a preform, and contacting said preform with said gelling agent and gelling said polysaccharide, to give said MOF-based product. In a powder of grains, said grains consist of MOF-based products, each of said products comprises particles bound by a binder, said binder comprises a gelled polysaccharide, said particles are MOF-based particles, and said powder has a mean circularity of less than 0.90.

Description

DESCRIPTION

TITLE: Process for making MOF product and grain powder into MOF product

Technical area

The present invention relates to a process for manufacturing an MOF product and grain powder into an MOF product.

Prior technique

In a well-known way, a metallo-organic network, or "Metal Organic Framework", most often called "MOF" according to the English abbreviation, is a material consisting of metal ions or metal clusters and organic ligands, organized in to form a porous crystal lattice.

Their high microporosity and specific surface make it possible to envisage many industrial applications, particularly in the fields of gas storage or separation, as well as in catalysis. However, MOFs are conventionally presented in the form of powders, which makes them difficult to use in said applications.

Patent GB2490473 describes products based on MOF in the form of spheres, the MOF particles being bound by a gelled alginate.

There is a need for MOF-based products, in particular powders, obtained by shaping an MOF powder, said products being able to be easily handled, having a high adsorption capacity, for a mass of MOF substantially identical.

An object of the invention is to meet, at least partially, this need.

Disclosure of Invention

According to the invention, this object is achieved by means of a method for manufacturing a product based on MOF comprising at least the following steps: a) mixing of raw materials to form a starting charge, said starting charge comprising an MOF powder, or a mixture of at least two MOF powders, and a polysaccharide which can be gelled under the action of a gelling agent, the mass ratio of the quantity of said polysaccharide to the total quantity of said polysaccharide and of the or MOF powders in said mixture being greater than or equal to 0.1% and less than or equal to 10%, b) shaping said starting charge according to a shaping technique chosen from extrusion, tape casting and screen printing, so as to obtain a preform, c) bringing said preform into contact with said gelation and gelation of said polysaccharide so as to obtain said MOF-based product, d) optionally, drying of said MOF-based product.

The inventors have discovered that the process according to the invention allows the manufacture of products based on MOF, having a surprisingly high adsorption capacity per gram of MOF contained in said product. In particular, it has been discovered that the selection of the shaping technique in step b) associated with gelation of the polysaccharide, preferably alginate, makes it possible to achieve this result, unlike the beads manufactured according to GB2490473 in a drip process (or "dripping" in English).

It has been discovered in particular that the shaping of said product according to one of the techniques described above and leading in particular to products whose shapes deviate from the sphere, unexpectedly makes it possible to improve its absorption capacity.

According to preferred but non-limiting embodiments of the present invention, which can, where appropriate, be combined with each other:

- the mass ratio of the amount of polysaccharide to the total amount of said polysaccharide and of the MOF powder(s) is greater than or equal to 1% and less than or equal to 8%; the MOF particles are particles of an MOF or a mixture of at least two populations of MOF particles chosen from MOF-O, MOF-2, MOF-3, MOF-4, MOF-5, MOF-6, MOF-7, MOF-8 MOF-9, MOF-11, MOF-12, MOF-20, MOF-25, MOF-26, MOF-31, MOF-32, MOF-33, MOF-34, MOF-36 , MOF-37, MOF-38, MOF-39, MOF-47, MOF-49, MOF-69a, MOF-69b, MOF-74, MOF-101 , MOF-102, MOF-107, MOF-108, MOF -110, MOF-177, MOF-j, MOF-n, IRMOF-1, IRMOF-2, IRMOF-3, IRMOF-4, IRMOF-5, IRMOF-6, IRMOF-7, IRMOF-8, IRMOF-9 , IRMOF-10, IRMOF-11 , IRMOF-12, IRMOF-13, IRMOF-14, IRMOF-15, IRMOF-16, IRMOF-17, IRMOF-18, IRMOF-19, IRMOF-20, AS 16, AS27- 2, AS32, AS54-3, AS61-4, AS68-7, BPR43G2, BPR48A2, BPR49B1, BPR68D10, BPR69B1, BPR73E4, BPR76D5, BPR80D5, BPR92A2, BPR95C5, UiO-66, UiO-67, UiO-68, N013, N029, NO305, NO306A, NO330, N0332, N0333, N0335, N0336, HKUST-1, MIL-100 and MIL101;

- the polysaccharide comprises a group capable of forming an ionic bond with a gelling agent, said group being chosen from a carboxylate group COO or a sulfonate group S0 ₃ ;

- the polysaccharide capable of forming an ionic bond with a gelling agent comprises a group capable of forming an ionic bond with a gelling agent chosen from divalent cations, trivalent cations, tetravalent cations, organic molecules comprising at least two groups each having an elementary or partial positive charge, and mixtures thereof;

- the polysaccharide is an alginate or a pectin, preferably an alginate;

- the starting charge consists of the MOF powder(s), the polysaccharide capable of forming an ionic bond with a gelling agent, a solvent, an acid, a base, a organic binder, a plasticizer, a lubricant and pore-forming particles;

- the gelling agent is chosen from Ca, Sr, Ba and mixtures thereof, preferably Ca;

- in step b), the starting charge is shaped by screen printing;

- the method comprises a step d) of drying.

In particular, a product finally obtained according to the manufacturing process according to the invention advantageously has a circularity Ci of less than 0.90, and preferably less than 0.88, or even less than 0.86. A sum of products according to the invention can advantageously constitute, at least partially and preferably entirely, the grains of a powder which is also the subject of the present invention. Preferably at least 50% by number and preferably at least 80%, or even at least 90%, and even more preferably substantially all of the grains of said powder are products capable of being obtained or obtained according to a process according to invention.

The invention thus also relates to a grain powder, said grains being made up of MOF-based products, each of said products comprising particles linked by a binder, said binder comprising a gelled polysaccharide, said particles being essentially, preferably being, MOF particles, said powder having an average circularity of less than 0.90.

Preferably, at least a portion and preferably all of the products of said powder are obtained or capable of being obtained by a process as described above.

By "MOF-based product" is meant that said product may comprise particles of a single MOF or a mixture of at least two populations of MOF particles, preferably at least two of said populations of MOF particles are in one different MOF, in particular chosen from the following list.

- The powder has an average circularity of less than 0.88, or even less than

0.86;

- said binder comprises a gelled polysaccharide comprising a group establishing an ionic bond with divalent cations, trivalent cations, cations tetravalent, organic molecules comprising at least two groups each having an elementary or partial positive charge, and mixtures thereof;

- said gelled polysaccharide is a gelled alginate or a gelled pectin; said MOF particles are particles of an MOF or a mixture of at least two populations of MOF particles chosen from MOF-O, MOF-2, MOF-3, MOF-4, MOF-5, MOF-6, MOF-7, MOF-8 MOF-9, MOF-11, MOF-12, MOF-20, MOF-25, MOF-26, MOF-31, MOF-32, MOF-33, MOF-34, MOF-36 , MOF-37, MOF-38, MOF-39, MOF-47, MOF-49, MOF-69a, MOF-69b, MOF-74, MOF-101 , MOF-102, MOF-107, MOF-108, MOF -110, MOF-177, MOF-j, MOF-n, IRMOF-1, IRMOF-2, IRMOF-3, IRMOF-4, IRMOF-5, IRMOF-6, IRMOF-7, IRMOF-8, IRMOF-9 , IRMOF-10, IRMOF-11 , IRMOF-12, IRMOF-13, IRMOF-14, IRMOF-15, IRMOF-16, IRMOF-17, IRMOF-18, IRMOF-19, IRMOF-20, AS16, AS27-2 , AS32, AS54-3, AS61-4, AS68-7, BPR43G2, BPR48A2, BPR49B1 , BPR68D10, BPR69B1 , BPR73E4, BPR76D5, BPR80D5, BPR92A2, BPR95C5, UiO-66, UiO-67, UiO-68, N013, N029 , NO305, NO306A, NO330, N0332, N0333, N0335, N0336, HKUST-1, MIL-100 and MIL101;

- the MOF-based product of the grains of the powder contains a mass quantity of MOF particles greater than or equal to 90% and less than or equal to 99.9%, based on the mass of said MOF-based product after drying , said drying being carried out for 12 hours:

- at the MOF degradation temperature minus 5°C or at the lowest MOF degradation temperature minus 5 °C, if said temperature is less than 100 °C, or

- to 100 'O if the degradation temperature of the MOF minus 5 'O or the lowest degradation temperature of the MOFs minus 5 'O is greater than or equal to 100 'O.

The invention finally relates to a device for filtering liquids, a device for filtering gases, a device for storing liquids, a device for storing gases, a catalyst support, comprising a powder according to the invention or a powder of grains comprising and preferably consisting of MOF-based products obtained or capable of being obtained by a process according to the invention.

Definitions

- By MOF powder is conventionally meant a set of MOF particles.

- The term "polysaccharides", according to the classic definition, refers to polymers composed of sequences of saccharide units linked by glycosidic bonds.

- The term "gellable polysaccharide" under the action of a gelling agent, a polysaccharide capable of forming a gel under the action of said gelling agent. - A gelled polysaccharide results from the association of polysaccharide chains under the action of a gelling agent. By way of example, alginate has the formula (CeFLO^ _ri . Alginate is a polyosidic chain comprising carboxylate groups (COO ). Ca ²⁺ calcium ions (gelling agent) react with two strands of alginate , that is to say with the carboxylate groups COO , leading to the polymerization of the alginate chains and the bonding of the molecules to each other.The reaction thus allows the creation of a gel.

- The term “MOF degradation temperature” refers to the start temperature of the last mass loss peak of the MOF (in other words, the peak found at the highest temperatures), as observed in thermogravimetric analysis (TGA ).

- The term "median size" of a powder of grains or particles means the size dividing said grains or said particles of the powder, into first and second populations equal in number, these first and second populations comprising only grains, respectively particles having a size greater than or equal to, or less than, respectively, the median size. The median size can for example be determined using a laser particle sizer.

- We call "circularity" of a product or a grain observed in a powder, the ratio PD/R _G , Pr designating the perimeter of the said product or grain as observed, and PD designating the perimeter of the disc having the same surface than that of said product or grain as observed. The circularity depends on the viewing direction.

As represented in FIG. 1, to evaluate the circularity “Ci” of a grain G, the perimeter PD of the disk D having an area A _p equal to the area A _G of the grain G is determined on a photograph of this grain. The perimeter P _r of this grain is also determined. The circularity is equal to the ratio of PD/R _G .

Thereby

The more elongated the grain, the lower the circularity.

- The "average circularity" Ci ₅ o of a set of grains is the arithmetic mean of the circularities of the grains of this set, said circularities being able to be evaluated using a device of the Morphologi® G3 type marketed by the company Malvern . According to the invention, the average circularity is determined from at least 1000 grains of the powder, so that the direction of observation does not or substantially does not impact the value thereof.

All percentages herein are percentages by weight, unless otherwise indicated. The adsorption of a powder of MOF-based product grains can be conventionally measured using a breakthrough curve, making it possible to determine the maximum mass quantity of a molecule (for example toluene) that can be adsorbed. Adsorption is expressed as the ratio of said amount to the mass of MOF particles present in the MOF product of the powder grains.

The verbs “contain”, “understand” and “present” must be interpreted in a broad, non-limiting way, unless otherwise indicated.

Figure 1 describes the elements taken into account for the determination of the circularity Ci of a grain.

Figure 2 shows the number distribution of the circularity of the grains of the powder according to comparative example 1.

Figure 3 shows the number distribution of the circularity of the grains of the powder according to example 2 according to the invention.

Figure 4 shows 10 2D shots of the grains of the powder according to comparative example 1.

Figure 5 shows 10 2D shots of the grains of the powder according to example 2 according to the invention.

detailed description

A method according to the invention will now be detailed.

In step a), the starting charge comprises at least one MOF powder.

In one embodiment, the starting charge comprises an MOF powder.

In one embodiment, the starting charge comprises at least two MOF powders, preferably at least two of said MOF powders are in a different MOF.

Preferably, the MOF is chosen from MOF-0, MOF-2, MOF-3, MOF-4, MOF-5, MOF-6, MOF-7, MOF-8, MOF-9, MOF-11, MOF-12 , MOF-20, MOF-25, MOF-26, MOF-31 , MOF-32, MOF-33, MOF-34, MOF-36, MOF-37, MOF-38, MOF-39, MOF-47, MOF -49, MOF-69a, MOF-69b, MOF-74, MOF-101, MOF-102, MOF-107, MOF-108, MOF-110, MOF-177, MOF-j, MOF-n, IRMOF-1 , IRMOF-2, IRMOF-3, IRMOF-4, IRMOF-5, IRMOF-6, IRMOF-7, IRMOF-8, IRMOF-9, IRMOF-10, IRMOF-11 , IRMOF-12, IRMOF-13, IRMOF -14, IRMOF-15, IRMOF-16, IRMOF-17, IRMOF-18, IRMOF-19, IRMOF-20, AS16, AS27-2, AS32, AS54-3, AS61-4, AS68-7, BPR43G2, BPR48A2 , BPR49B1 , BPR68D10, BPR69B1 , BPR73E4, BPR76D5, BPR80D5, BPR92A2, BPR95C5, UiO-66, UiO-67, UiO-68, N013, N029, NO305, NO306A, NO330, N0332, N0333, N0365, HK , MIL-100 and MIL101. Preferably, the MOF is chosen from UiO-66 and HKUST-1.

Preferably, the median size of the MOF powder is greater than 0.1 μm and/or less than 100 μm. Preferably, the degradation temperature of the MOF, or even of each MOF, is greater than 120° C., preferably greater than 130° C., preferably greater than 140° C. In one embodiment, the degradation temperature of the MOF, or even of each MOF, is less than 250°C, preferably less than 200°C.

The starting charge contains a polysaccharide comprising a group capable of forming an ionic bond with a gelling agent for the formation of a gelled polysaccharide, in particular in an amount such that the mass ratio of the amount of said polysaccharide to the total amount of said polysaccharide and of the MOF powder(s) is greater than or equal to 0.1% and less than or equal to 10%. Preferably, said mass ratio is greater than or equal to 0.5%, preferably greater than or equal to 1%, preferably greater than or equal to 2%, and preferably less than or equal to 8%, preferably less than or equal to 7%.

Preferably, the group of the polysaccharide capable of forming an ionic bond with a gelling agent is chosen from a carboxylate group COO— or a sulfonate group S0 ₃ , more preferably said group is a carboxylate group COO—. Preferably, the polysaccharide comprises a group capable of forming an ionic bond with a gelling agent chosen from divalent cations, trivalent cations (for example an Fe or Al cation), tetravalent cations, organic molecules comprising at least two groups each having an elementary or partial positive charge, in particular polyacids (such as citric acid, oxalic acid or maleic acid, in particular in a medium having a pH of less than 2, or even less than 1 ), and mixtures thereof, preferably chosen from divalent cations, trivalent cations, and mixtures thereof, preferably chosen from alkaline-earth cations, preferably chosen from Ca, Sr, Ba cations and mixtures thereof. Preferably, the polysaccharide comprises a group capable of forming an ionic bond with a Ca cation.

Preferably, the polysaccharide comprising a group capable of forming an ionic bond with a gelling agent is chosen from alginates and pectins.

Preferably, the polysaccharide comprising a group capable of forming an ionic bond with a gelling agent is chosen from alginates, preferably from sodium alginates, potassium alginates, ammonium alginates, and mixtures thereof. Preferably the alginate is an ammonium alginate.

Preferably, the starting charge contains an MOF powder and a polysaccharide comprising a group capable of forming an ionic bond with a gelling agent. In the process according to the invention, the polysaccharide comprising a group capable of forming an ionic bond with a gelling agent, preferably alginate, can be provided in the form of a solution. In the process according to the invention, the MOF powder(s) and the polysaccharide capable of forming an ionic bond with a gelling agent can be provided in the form of a suspension or any other form comprising said powders and said polysaccharide. As is well known to those skilled in the art, the starting charge may comprise, in addition to the MOF powder(s) and the polysaccharide comprising a group capable of forming an ionic bond with a gelling agent, a solvent and/or an organic binder and or a plasticizer and/or a lubricant and/or pore-forming particles, the natures and quantities of which are adapted to the shaping method of step b).

Preferably the solvent is water. The amount of solvent is adapted to the shaping process implemented during step b).

The starting charge optionally contains an organic binder facilitating the constitution of the preform, preferably in a content of between 0.1% and 10%, preferably between 0.2% and 2% by mass based on the mass of the MOF powder(s) and the polysaccharide comprising a group capable of forming an ionic bond with a gelling agent. All the organic binders conventionally used for the manufacture of porous ceramic products can be used, for example polyvinyl alcohol (PVA) or polyethylene glycol (PEG), methylstearate, ethylstearate, waxes, polyolefins, oxides of polyolefins, glycerin, propionic acid, maleic acid, benzyl alcohol, isopropanol, butyl alcohol, a dispersion of paraffin and polyethylene, and mixtures thereof.

The starting charge optionally contains a plasticizer, also facilitating the constitution of the preform.

Preferably, the content of plasticizer is between 1% and 10%, preferably between 1% and 5%, by mass based on the mass of the MOF powder(s) and of the polysaccharide comprising a group suitable forming an ionic bond with a gelling agent. The plasticizer can constitute an organic binder.

All the plasticizers conventionally used for the manufacture of porous ceramic products can be used, for example polyethylene glycol, polyolefin oxides, hydrogenated oils, alcohols, in particular glycerol and glycol, esters, starch, and their mixtures.

The starting charge optionally contains a lubricant, also facilitating the constitution of the preform.

Preferably, the lubricant content is between 1% and 10%, preferably between 1% and 5% by mass based on the mass of the MOF powder(s) and the polysaccharide comprising a group capable of form an ionic bond with a gelling agent. All the lubricants conventionally used for the manufacture of porous ceramic products can be used, for example petroleum jelly and/or waxes.

The starting charge optionally contains pore-forming particles, well known to those skilled in the art, which are intended to be eliminated during the process according to the invention, thus leaving room for pores. Their quantity and their dimensions are chosen so as in particular to adjust the pore volume in the MOF-based product obtained at the end of step c) or d). Preferably, said pore-forming particles are made of a material soluble in the solvent.

The pH of the starting charge can be adjusted to a value preferably greater than 1, preferably greater than 2, and/or less than 7, preferably less than 6. Conventionally, the pH of the starting charge can be adjusted by adding an acid and/or a base.

The presence and nature of the binder and/or the lubricant and/or the plasticizer depend in particular on the shaping technique used in step b).

In a preferred embodiment, the starting charge does not contain any constituents other than the MOF powder(s), the polysaccharide comprising a group capable of forming an ionic bond with a gelling agent, a solvent, a acid, a base, an organic binder, a plasticizer, a lubricant and pore-forming particles.

In one preferred embodiment among all, the starting charge does not contain any constituents other than the MOF powder(s), the polysaccharide comprising a group capable of forming an ionic bond with a gelling agent, a solvent , an acid and a base.

Preferably, the polysaccharide comprising a group capable of forming an ionic bond with a gelling agent and the solvent, preferably water, are mixed so as to obtain an intimate mixture. Then the other constituents of the starting charge, in particular the MOF powder(s), any binder, lubricant, plasticizer and pore-forming particles are added with stirring. The amount of solvent, preferably water, can be added several times, in a determined amount depending on the technique chosen for shaping. The acid or the base, optional, are then introduced to adjust the pH of the suspension.

The mixing of the various constituents can be carried out according to any technique known to those skilled in the art, for example in a mixer, preferably in a high-intensity mixer or in a Z-arm mixer, in a turbulat, in a jar mill with balls, preferably alumina balls. Preferably, the mixing is carried out in a high intensity mixer or in a Z-arm mixer.

The total mixing time is preferably greater than 5 minutes, and preferably less than 30 minutes, preferably less than 20 minutes. In step b), the starting charge is shaped according to a shaping technique chosen from extrusion, strip casting, screen printing, so as to obtain a preform.

In a preferred embodiment, the shaping is carried out by screen printing.

Extrusion, tape casting, screen printing, are shaping techniques well known to those skilled in the art.

Extrusion is a forming technique in which a feedstock is forced through a die. Within the meaning of the present description, extrusion comprises a 3D printing technique in which a filament of the starting charge is extruded from a nozzle of generally reduced size, the nozzle and/or the support receiving the filament move, this technique being referred to as “robocasting” in English.

Tape casting, or "tape casting" in English, is a shaping technique consisting in spreading a starting charge on a flat surface, the spreading of the starting charge being obtained by the relative movement of a tank or sabot containing said starting charge and a support. The starting charge is thus rolled by its passage between the blade of the tank and the support, the height of the knife of the tank relative to the support determines the thickness of the starting charge deposited.

Serigraphy, or "screen printing" in English, is a shaping technique consisting in obtaining objects by spreading a material under pressure through a perforated screen.

At the end of step b), the preforms obtained can form a powder having an average circularity of less than 0.90, preferably less than 0.88, preferably less than 0.86, or even less than 0.84 , or even less than 0.82.

In one embodiment, the preforms are in the form of cylinders.

In step c), the preform is brought into contact with a solution comprising a gelling agent, capable of causing the polysaccharide to gel, so as to obtain the MOF-based product.

The solution comprising a gelling agent capable of causing the polysaccharide to gel is well known to those skilled in the art.

The gelling agent is preferably chosen from divalent cations, trivalent cations, tetravalent cations, organic molecules comprising at least two groups each having an elementary or partial positive charge, in particular polyacids (such as acid citric acid, oxalic acid or maleic acid, in particular in a medium having a pH of less than 2, or even less than 1), and mixtures thereof, preferably chosen from divalent cations, trivalent cations, and their mixtures, preferably chosen from alkaline-earth cations, preferably chosen from Ca, Sr, Ba cations and mixtures thereof. Preferably the gelling agent is a Ca cation.

The solution containing the gelling agent is preferably chosen from a solution comprising a divalent cation salt or a solution comprising a trivalent cation salt.

Preferably, the solution comprising a divalent cation salt or a trivalent cation salt is chosen from an iodide solution of said cation and/or a chloride solution of said cation. Preferably, the gelation solution is a solution comprising an alkaline-earth cation iodide and/or an alkaline-earth cation chloride. More preferably, the gelation solution is a solution comprising an alkaline earth cation chloride, preferably a solution comprising calcium chloride.

In a preferred embodiment, the gelling solution is a calcium chloride solution, the calcium chloride concentration of which is preferably greater than 1 mol/l, preferably greater than 2 mol/l of solution.

The bringing into contact can for example be carried out by immersing the preform in a bath of gelling solution or by spraying the preform with the gelling solution.

In one embodiment, step b) and step c) are combined, in particular when the metal ion of the MOF is a gelling agent capable of causing the polysaccharide to gel. For example, MOF HKUST-1 has copper cations capable of acting as a polysaccharide gelling agent.

At the end of step c), a product based on MOF is obtained. Said MOF-based product can form a powder of grains of MOF-based products having, preferably, an average circularity of less than 0.90, preferably less than 0.88, preferably less than 0.86, or even less to 0.84, or even less than 0.82.

In one embodiment, said MOF-based product may be in the form of cylinders.

Preferably, the preform is shaped so that the largest dimension of the MOF-based product is less than 100 mm, preferably less than 80 mm, preferably less than 50 mm, preferably less than 30 mm, or even less than 10 mm and or that the smallest dimension of the MOF product in a plane perpendicular to the direction of the largest dimension is greater than 100 µm (micrometers).

Preferably more than 50%, preferably more than 60%, preferably more than 70%, preferably more than 80%, preferably more than 90%, preferably more than 99%, by number, of the grains of product based on MOF of the powder according to the invention have a greatest dimension less than 100 mm, preferably less than 80 mm, preferably less than 50 mm, preferably less than 30 mm, preferably less than 20 mm, or even less than 10 mm, and more preferably, a smaller dimension, in a plane perpendicular to the direction of the largest dimension, greater than 100 p.m.

Preferably, the powder of MOF-based product grains has a median size greater than 0.1 mm, preferably greater than 0.3 mm, preferably greater than 0.5 mm, and preferably less than 5 mm, of preferably less than 4 mm, preferably less than 3 mm, preferably less than 2 mm.

In step d), optional, the MOF-based product is dried.

Preferably, the maximum temperature reached during said drying is greater than 20°C, preferably greater than 40°C, and preferably less than:

- the MOF degradation temperature minus 5'O or the lowest MOF degradation temperature minus 5'O, preferably lower than the MOF degradation temperature minus 10'O or the lowest MOF degradation temperature minus l O'O, if the degradation temperature of the MOF minus 5'O or the lowest degradation temperature of the MOFs minus 5°C is lower than ISO'O, or lower than 135°C, preferably lower than ISO' O, or even less than ^O'O, even less than 100 'O, even less than 80 'O, if the MOF degradation temperature minus 5 'O or the lowest MOF degradation temperature minus 5°C is higher or equal to 135 'O .

Preferably again, the drying cycle has a plateau at said maximum temperature reached. The holding time at the level is preferably greater than 1 hour, preferably greater than 2 hours, preferably greater than 5 hours, or even greater than 10 hours, or even greater than 15 hours, and preferably less than 30 hours, or even less at 8 p.m., or even less than 3 p.m. Drying is preferably carried out in air, at atmospheric pressure.

When the MOF powder used in step a) is a UiO-66 powder, the degradation temperature of said MOF being substantially equal to 400°, the maximum temperature reached during optional step c) is preferably below 135°C.

At the end of step d), a product based on dry MOF is obtained, said product forming a powder of grains of products based on MOF having, preferably, an average circularity of less than 0.90, preferably less than 0.88, preferably less than 0.86, or even less than 0.84, or even less than 0.82.

For example, the average circularity can be greater than 0.60, or even greater than 0.65, or even greater than 0.70.

In one embodiment, said product is in the form of cylinders. The method according to the invention can also comprise an optional machining step occurring after step c) and/or after step d). This machining step makes it possible in particular to modify the shape and/or the surface condition of the MOF-based product. Any state-of-the-art machining technique can be used, including sawing, wire cutting, laser cutting, drilling and punching. Preferably, when the shaping technique chosen in step b) is strip casting, the method according to the invention comprises such a machining step.

The process as just described makes it possible in particular to obtain a product, in particular a powder, as described below.

The invention also relates to a grain powder, said grains being constituted by MOF-based products, each of said products comprising particles linked by a binder, said binder comprising a gelled polysaccharide, said particles being essentially, preferably being, particles of MOF, said powder having an average circularity of less than 0.90.

Preferably, said powder comprises, and preferably consists of, products obtained or capable of being obtained by a process as described above. Preferably at least 50% by number and preferably at least 80%, or even at least 90%, and even more preferably substantially all of the grains of said powder are products capable of being obtained or obtained according to a process according to invention.

Preferably, the grain powder according to the invention has an average circularity of less than 0.88, preferably less than 0.86, or even less than 0.84, or even less than 0.82.

Preferably, the binder of the product based on MOF of the grains of the powder according to the invention comprises, preferably consists essentially of, a gelled polysaccharide comprising a group establishing an ionic bond with the divalent cations, the trivalent cations, the cations tetravalent, organic molecules comprising at least two groups each having an elementary or partial positive charge, in particular polyacids (such as for example citric acid, oxalic acid or maleic acid, in particular in a medium having a lower pH than 2, or even less than 1), and mixtures thereof, preferably chosen from divalent cations, trivalent cations, and mixtures thereof, preferably with alkaline-earth cations, preferably chosen from Ca, Sr, Ba and mixtures thereof, preferably a Ca cation.

Preferably said gelled polysaccharide is a gelled alginate or a gelled pectin, preferably a gelled alginate. In the product based on MOF of the grains of the powder according to the invention, the gelled polysaccharide, in particular the gelled alginate, contained in the binder can for example be revealed by steric exclusion chromatography.

In a preferred embodiment, the product based on MOF of the grains of the powder according to the invention consists of particles bound by a binder consisting essentially, preferably consisting of a gelled polysaccharide, preferably a gelled alginate or a pectin gelled, preferably a gelled alginate, said particles being essentially, preferably being MOF particles.

Preferably, the MOF particles of the product based on MOF of the grains of the powder according to the invention are particles of an MOF or a mixture of at least two populations of MOF particles chosen from MOF-O, MOF- 2, MOF-3, MOF-4, MOF-5, MOF-6, MOF-7, MOF-8 MOF-9, MOF-11, MOF-12, MOF-20, MOF-25, MOF-26, MOF -31, MOF-32, MOF-33, MOF-34, MOF-36, MOF-37, MOF-38, MOF-39, MOF-47, MOF-49, MOF-69a, MOF-69b, MOF-74 , MOF-101, MOF-102, MOF-107, MOF-108, MOF-110, MOF-177, MOF-j, MOF-n, IRMOF-1, IRMOF-2, IRMOF-3, IRMOF-4, IRMOF -5, IRMOF-6, IRMOF-7, IRMOF-8, IRMOF-9, IRMOF-10, IRMOF-11, IRMOF-12, IRMOF-13, IRMOF-14, IRMOF-15, IRMOF-16, IRMOF-17 , IRMOF-18, IRMOF-19, IRMOF-20, AS16, AS27-2, AS32, AS54-3, AS61-4, AS68-7, BPR43G2, BPR48A2, BPR49B1 , BPR68D10, BPR69B1 , BPR73E4, BPR76D5, BPR80D5, BPR92A2 , BPR95C5, UiO-66, UiO-67, UiO-68, N013, N029, NO305, NO306A, NO330, N0332, N0333, N0335, N0336, HKUST-1, MIL-100 and MIL101, preferably chosen from UiO-66 and HKUST-1.

In one embodiment, when the MOF-based product of the grains of the powder according to the invention comprises a mixture of at least two populations of MOF particles, at least two of said populations of MOF particles are in a different MOF .

Preferably, in the MOF-based product of the grains of the powder according to the invention, the degradation temperature of the MOF, or even of each MOF, is greater than 120° C., preferably greater than 130° C., preferably greater than at 140' W. In one embodiment, the degradation temperature of the MOF, or even of each MOF, is less than 250°C, preferably less than 200°C.

Preferably, in the MOF-based product of the grains of the powder according to the invention, the mass ratio of the amount of gelled polysaccharide to the total amount of said gelled polysaccharide and of the MOF particles is greater than or equal to 0.1% , preferably greater than or equal to 0.5%, preferably greater than or equal to 1%, preferably greater than or equal to 2%, and less than or equal to 10%, preferably less than or equal to 8%, preferably less or equal to 7%, after drying for 12 hours: - at the MOF degradation temperature minus 5 'O or at the lowest MOF degradation temperature minus 5 'O, if said temperature is below 100°C, or at 100°C if the MOF degradation temperature minus 5'O or the lowest degradation temperature of MOFs minus 5'O is greater than or equal to 100°C.

Preferably, in the MOF-based product of the grains of the powder according to the invention, the quantity by mass of MOF particles is greater than or equal to 90%, preferably greater than or equal to 92%, preferably greater than or equal to 93%, and less than or equal to 99.9%, preferably less than or equal to 99.5%, preferably less than or equal to 99%, preferably less than or equal to 98%, based on the mass of said product based on MOF after drying, said drying being carried out for 12 hours:

- at the MOF degradation temperature minus 5'O or at the lowest MOF degradation temperature minus 5'O, if said temperature is less than 100°C, or

- at 100°C if the degradation temperature of the MOF minus 5'O or the lowest degradation temperature of the MOFs minus 5'O is greater than or equal to 100°C.

The MOF-based product grains of the powder according to the invention may be in the form of cylinders.

Preferably more than 50%, preferably more than 60%, preferably more than 70%, preferably more than 80%, preferably more than 90%, preferably more than 99%, by number, of the grains of product based on MOF of the powder according to the invention have a greatest dimension of less than 100 mm, preferably less than 80 mm, preferably less than 50 mm, preferably less than 30 mm, or even less than 10 mm, and of more preferably, a smaller dimension, in a plane perpendicular to the direction of the larger dimension, greater than 100 μm.

Preferably, the powder according to the invention has a median size greater than 0.1 mm, preferably greater than 0.3 mm, preferably greater than 0.5 mm, and preferably less than 5 mm, preferably less than 4 mm, preferably less than 3 mm, preferably less than 2 mm.

Examples

The following non-limiting examples are given for the purpose of illustrating the invention.

Measurement protocol

The toluene adsorption capacity of the examples is measured conventionally from a breakthrough curve carried out in a fixed bed, at room temperature, in a glass reactor having a diameter equal to 14 mm, with a gas flow composed of helium containing 100 ppm of toluene, injected at a flow rate of 6 liters per hour, the quantity of the products of the examples being between 0.6 g and 1 g, said products being dried beforehand at 50° C. for 15 minutes.

The result is expressed in mg of toluene per gram of MOF present in the characterized product (the products of Examples 1 and 2 contain a mass quantity of MOF particles equal to 95%).

The average circularity of the powders of the examples is measured on a Morphologi® G3 device marketed by the company Malvern, after having poured the powder to be analyzed onto the glass plate provided for this purpose, so as to obtain a monolayer, using an equal magnification at 2.5x.

Manufacturing protocol

The following raw materials were used for Examples 1 and 2:

- a powder of MOF UiO-66, marketed by the company Sigma Aldrich, having a median size equal to 1.3 μm, an ammonium alginate powder, marketed under the name E 401 by the company Matalgin,

- anhydrous calcium chloride marketed by the company Sigma Aldrich.

The powder of example 1, comparative, was shaped according to a conventional technique of drop by drop (or "dripping" in English) in the following manner. An aqueous suspension comprising, in mass percentages based on the MOF powder and the alginate, 5% ammonium alginate, was prepared. A mixer was used for this preparation: a solution containing the ammonium alginate was first formed by mixing the alginate and distilled water in a determined quantity to obtain at the end of the mixing an aqueous suspension comprising 20 % MOF powder by mass. Then, the MOF powder was added to said solution. The pH of the suspension was then adjusted to a value equal to 4.5 using 1 M NaOH.

The suspension was forced through a calibrated hole and at a flow rate making it possible to obtain, after drying, beads having, after drying, a median diameter of about 1.2 mm. The drops of suspension fell into a gelation bath of 2.7M calcium chloride, reacting with the ammonium alginate. The green beads were collected, washed, then dried at 50°C for 24 hours.

The grain powder of Example 2, according to the invention, was obtained using the process according to the invention, by screen printing in the following manner. In step a), 0.1 g of ammonium alginate is mixed in 8 g of distilled water using a paddle stirrer, then 1.9 g of MOF UiO-66 powder are added and the whole is kept under stirring for one hour, after the pH of the starting charge has been adjusted to a value equal to 4.5 by adding 1 M NaOH. the form of a homogeneous suspension. HAS step b), the starting charge is spread on a metal grid with a thickness equal to 1 mm and perforated with circular holes with a diameter equal to 1.5 mm, then scraped using a spatula on each side of the grid so that said starting charge fills the holes of said grid. The grid is then said to be “loaded”. In step c), the gelling agent in the form of a 2.7M calcium chloride solution is sprayed onto the charged grid and causes the ammonium alginate to gel. One hour after spraying the gelling agent on the charged grid, said grid is rinsed with demineralised water. Then in step d), after 24 hours of maintenance at room temperature, the grid is dried for 24 hours at 50 ^q C. The grains of MOF-based product present in the holes of the grid are then recovered at the using tapping on the grid. Said grains of the powder according to the invention are in the form of cylinders with an average length equal to 0.7 mm and an average diameter equal to 1.3 mm, as observed with a binocular.

Table 1 below summarizes the results obtained. [Table 1]

( ^* ): comparison

The analysis of figure 2 shows a single peak centered on a circularity of approximately 0.92, characteristic of a spherical shape of the grains, as can be deduced from figure 4, for which all the images reported are discs, whatever or the positioning of the grain. The analysis of figure 3 shows two distinct peaks corresponding to the two possible positions of the grain of cylindrical shape during the analysis: either on its circular face (peak centered on a circularity of approximately 0.89), as for the grain 5.1, or on one side of said cylinder (peak centered on a circularity of approximately 0.75), as for grain 5.2, as observed in the photographs shown in figure 5.

A comparison of Example 1, comparative, manufactured according to the teaching of GB2490473, and Example 2 (according to the invention), shows that the powder according to the invention, manufactured according to the method according to the invention, has an adsorption capacity equal to 14.2 mg/g of MOF present in the powder of the example, greater by 94.6% than that of the powder of comparative example 3, equal to 7.4 mg/g of MOF present in the powder of the example. This surprising result shows the impact on the adsorption capacity of the process according to the invention and of the powder according to the invention.

Of course, the invention is not limited to the embodiments described, provided for illustration purposes only.

Claims

1 . Process for manufacturing an MOF-based product comprising at least the following steps: a) mixing raw materials to form a starting charge, said starting charge comprising an MOF powder or a mixture of at least two MOF and a polysaccharide which can be gelled under the action of a gelling agent, the mass ratio of the quantity of said polysaccharide to the total quantity of said polysaccharide and of the MOF powder(s) in the said mixture being greater than or equal to 0.1% and less than or equal to 10%, b) shaping said starting charge using a technique chosen from extrusion, tape casting and screen printing, so as to obtain a preform, c) bringing said preform into contact with said gelling agent and gelling said polysaccharide so as to obtain said MOF-based product.

2. Process for the manufacture of a product based on MOF according to the preceding claim, in which the mass ratio of the quantity of said polysaccharide to the total quantity of said polysaccharide and of the MOF powder(s) is greater than or equal to 1% and less than or equal to 8%.

3. Process for manufacturing a product based on MOF according to one of the preceding claims, in which the MOF particles are particles of an MOF or a mixture of at least two populations of MOF particles chosen from MOF -0, MOF-2, MOF-3, MOF-4, MOF-5, MOF-6, MOF-7, MOF-8 MOF-9, MOF-11, MOF-12, MOF-20, MOF-25, MOF-26, MOF-31, MOF-32, MOF-33, MOF-34, MOF-36, MOF-37, MOF-38, MOF-39, MOF-47, MOF-49, MOF-69a, MOF- 69b, MOF-74, MOF-101, MOF-102, MOF-107, MOF-108, MOF-110, MOF-177, MOF-j, MOF-n, IRMOF-1, IRMOF-2, IRMOF-3, IRMOF-4, IRMOF-5, IRMOF-6, IRMOF-7, IRMOF-8, IRMOF-9, IRMOF-10, IRMOF-11, IRMOF-12, IRMOF-13, IRMOF-14, IRMOF-15, IRMOF- 16, IRMOF-17, IRMOF-18, IRMOF-19, IRMOF-20, AS16, AS27-2, AS32, AS54-3, AS61-4, AS68-7, BPR43G2, BPR48A2, BPR49B1, BPR68D10, BPR69B1, BPR73E4, BPR76D5, BPR80D5, BPR92A2, BPR95C5, UiO-66, UiO-67, UiO-68, N013, N029, NO305, NO306A, NO330, N0332, N0333, N0335, N0336, HKUST-1, MIL-100 and MIL101.

4. A method of manufacturing a product based on MOF according to one of the preceding claims, in which the polysaccharide comprises a group capable of forming an ionic bond with a gelling agent, said group being chosen from a carboxylate group COO or a sulphonate group S0 ₃ .

5. Process for the manufacture of a product based on MOF according to one of the preceding claims, in which the polysaccharide capable of forming an ionic bond with a gelling agent comprises a group capable of forming an ionic bond with a gelling agent chosen from divalent cations, trivalent cations, tetravalent cations, organic molecules comprising at least two groups each having an elementary or partial positive charge, and mixtures thereof.

6. Process for the manufacture of a product based on MOF according to one of the preceding claims, in which the polysaccharide is an alginate or a pectin, preferably an alginate.

7. Process for the manufacture of a product based on MOF according to one of the preceding claims, in which the starting charge consists of the powder(s) of MOF, of the polysaccharide capable of forming an ionic bond with a gelling agent, a solvent, an acid, a base, an organic binder, a plasticizer, a lubricant and pore-forming particles.

8. Process for the manufacture of a product based on MOF according to one of the preceding claims, in which the gelling agent is chosen from Ca, Sr, Ba and their mixtures, preferably Ca.

9. A method of manufacturing a product based on MOF according to one of the preceding claims, in which, in step b), the starting charge is shaped by screen printing.

10. A method of manufacturing an MOF-based product according to one of the preceding claims, comprising a step d) of drying said MOF-based product.

11. Grain powder, said grains consisting of MOF-based products, each of said products comprising particles bound by a binder, said binder comprising a gelled polysaccharide, said particles being MOF particles, said powder having a lower average circularity at 0.90.

12. Powder according to the preceding claim, comprising, or consisting of, products obtained or capable of being obtained by a process according to one of claims 1 to 10.

13. Powder according to one of claims 11 and 12, having an average circularity of less than 0.86.

14. Powder according to one of claims 11 to 13, in which the said binder comprises a gelled polysaccharide comprising a group establishing an ionic bond with the divalent cations, the trivalent cations, the tetravalent cations, the molecules organic compounds comprising at least two groups each having an elementary or partial positive charge, and mixtures thereof.

15. Powder according to one of claims 11 to 14, in which said gelled polysaccharide is a gelled alginate or a gelled pectin.

16. Powder according to one of claims 11 to 15, in which said MOF particles are particles of an MOF or a mixture of at least two populations of MOF particles chosen from MOF-0, MOF-2, MOF -3, MOF-4, MOF-5, MOF-6, MOF-7, MOF-8, MOF-9, MOF-11, MOF-12, MOF-20, MOF-25, MOF-26, MOF-31, MOF-32, MOF-33, MOF-34, MOF-36, MOF-37, MOF-38, MOF-39, MOF-47, MOF-49, MOF-69a, MOF-69b, MOF-74, MOF- 101, MOF-102, MOF-107, MOF-108, MOF-110, MOF-177, MOF-j, MOF-n, IRMOF-1, IRMOF-2, IRMOF-3, IRMOF-4, IRMOF-5, IRMOF-6, IRMOF-7, IRMOF-8, IRMOF-9, IRMOF-10, IRMOF-11, IRMOF-12, IRMOF-13, IRMOF-14, IRMOF-15, IRMOF-16, IRMOF-17, IRMOF- 18, IRMOF-19, IRMOF-20, AS16, AS27-2, AS32, AS54-3, AS61-4, AS68-7, BPR43G2, BPR48A2, BPR49B1, BPR68D10, BPR69B1, BPR73E4, BPR76D5, BPR80D5, BPR92A2, BPR95C5, UiO-66, UiO-67, UiO-68, N013, N029, NO305, NO306A, NO330, N0332, N0333, N0335, N0336, HKUST-1, MIL-100 and MIL101.

17. Powder according to one of claims 11 to 16, in which the MOF-based product of the grains of said powder contains a mass quantity of MOF particles greater than or equal to 90% and less than or equal to 99.9%, based on the mass of said MOF product after drying, said drying being carried out for 12 hours: at the MOF degradation temperature minus 5'O or at the lowest MOF degradation temperature minus 5'O, if said temperature is less than 100°C, or -100°C if the degradation temperature of the MOF minus 5′O or the lowest degradation temperature of the MOFs minus 5′O is greater than or equal to 100°C.

18. Device for filtering liquids or gases, comprising a powder according to one of claims 11 to 17 or a powder of grains consisting of MOF-based products obtained or capable of being obtained by a process according to one of claims 1 to 10.

19. Device for storing liquids or gases comprising a powder according to one of claims 11 to 17 or a powder of grains consisting of MOF-based products obtained or capable of being obtained by a process according to one of claims 1 to 10.

20. Catalyst support comprising a powder according to one of claims 11 to 17 or a powder of grains consisting of MOF-based products obtained or obtainable by a process according to one of claims 1 to 10.