Magnetic mesoporous materials based on silica (3MS)

Abstract

The invention relates to a magnetic mesoporous material based on functionalised silica (3MS-f), the method comprising the steps of: i) hydrolysing and precondensing, in an acid medium, a silica precursor (SiO2) in the presence of a porogen compound having the formula (POE)n-(POP)m-(POE)n wherein: - POE is a polyoxyethylene block; - POP is a polyoxypropylene block; - n is equal to 20 or 106 and - m is equal to 70; ii) incorporating silica-coated superparamagnetic iron nanoparticles into the precondensed mixture obtained in step i) and continuing the condensation; iii) removing the porogen agent from the obtained condensed structure, whereby an organised magnetic mesoporous material based on silica (3MS) is obtained; iv) functionalising the material (3MS) obtained in the preceding step by covalently grafting at least one reactive function that is capable of forming a weak bond with at least one organic molecule of interest (MIO), the weak bond being selected in particular from among electrostatic bonds between oppositely charged groups such as carboxylate / ammonium, phosphonate / ammonium or sulphonate / ammonium and hydrophobic bonds such as bonds between alkyl chains or between aromatic groups; v) optionally, recovering the functionalised magnetic mesoporous material based on silica (3MS-f) obtained in the preceding step.

Description

[0001] Silica-based Magnetic Mesoporous Materials (3MS)

[0002] Field of invention

[0003] The present invention relates to a process for preparing functionalized Silica-based Magnetic Mesoporous Materials (3MS-f), the Silica-based Magnetic Mesoporous Materials (3MS), in particular functionalized (3MS-f), capable of being obtained by this process and their use for isolating and concentrating Organic Molecules of Interest (MIOs) by applying a magnetic field.

[0004] Technical background

[0005] The agri-food, agricultural and wine-growing industries generate a significant quantity of organic residues or waste, also known as co-products, which can be recovered by extracting molecules of interest with high added value (proteins, polypeptides, polyphenol polysaccharides, colorants, etc.) for various applications, particularly for the cosmetic, pharmaceutical and agri-food industries.

[0006] Several extraction methods (enzymatic, chemical, physical, etc.) exist and allow the isolation of these molecules of interest. However, they most often involve high-performance liquid chromatography (HPLC) techniques, which allow separation by chemical affinity, or dialysis membranes, allowing separation by size. The molecules of interest separated by these usual methods are therefore found in solution but at a very low concentration (a few ppm). Consequently, to these classic separation steps, it is generally necessary to add several concentration steps (centrifugation, filtration, drying, etc.), to remove the solvent.Typically, for a concentration of a product of interest recovered in the order of 10 mg / L by usual extraction techniques, it is necessary to eliminate water, which represents -99.99% of the total weight, which corresponds to hundreds of liters of solvent to recover only a few grams of said molecule of interest. These last two steps are very energy-intensive and thus increase both the environmental impact and the costs of the overall isolation process and therefore ultimately the price of the isolated molecule of interest. Consequently, current separation / isolation methods constitute a considerable obstacle in the recovery of co-products, particularly from the agri-food, agricultural or wine-growing industries.

[0007] There is therefore a real need for a process that allows the isolation and concentration of molecules of biological interest, which is less expensive, more ecological and / or quicker to implement, in particular to promote the recovery of co-products.

[0008] Summary of the invention

[0009] Functionalized (3MS-f) silica-based magnetic mesoporous materials (3MS) have now been discovered, combining both chemical and size selectivity, which allow the easy, selective and rapid isolation of organic molecules of interest, possessing functional groups (-NH2, -COOH, ...) in their structure.

[0010] Furthermore, compared to traditional extraction techniques, they allow a considerable reduction in the quantities of solvent and therefore the energy required to isolate these molecules, thus reducing both the environmental impact and the final cost of the molecules of interest thus isolated.

[0011] In addition, these materials can be regenerated and therefore recycled after their use in the process of isolating the molecule of interest, which further reduces the environmental impact of the process.

[0012] More particularly, the inventors have developed a process for incorporating superparamagnetic iron oxide particles into Organized Mesoporous Structures (OMS) of the SBA-15 or SBA-16 type, while preserving, on the one hand, the porosity and the specific surface area characteristic of these OMS structures, and, on the other hand, the superparamagnetic properties of the incorporated iron oxide particles.

[0013] The materials (3MS) obtained can then be functionalized according to the target MIO molecule, which one wishes to isolate or concentrate, by introducing, in particular inside the pores, a reactive function capable of reacting with at least one of the functional groups present in the chemical structure of the target molecule, to form a weak bond, in particular electrostatic, with the target molecule. The material (3MS-MIO) thus obtained can then be concentrated and recovered, by means of a magnet, thanks in particular to its superparamagnetic properties, then the molecule of interest MIO can then be released by breaking the 3MS-MIO bond, and the material (3MS-f), regenerated to be reused in a new cycle of isolation and concentration of a MIO.For example, in order to isolate a MIO molecule carrying a carboxylic acid functional group (-COOH), the 3MS material can be functionalized by attaching a reactive function (-NH2) to form a functionalized material (3MS-f), in this case a material (3MS-NHs. + ), capable of forming an electrostatic bond between the carboxylate functions (COO-) of the target MIO.

[0014] Thus, the inventors were able to show that when they are introduced during or at the end of the extraction process, these functionalized materials (3MS-f), have the capacity to preferentially fix a molecule of organic interest, by acting on the one hand on the size of the pores of the mesoporous structure which will make it possible to exclude the molecules present in the extract, having a steric hindrance greater than that of the size of the pores and therefore of the target MIO molecule, and on the other hand, by acting on the chemical affinity of the MIO molecule for the reactive function fixed inside the pores resulting in the formation of a weak bond (3MS-MIO).

[0015] Once the organic molecule of interest is fixed on the inorganic material (3MS-MIO), a magnetic field can be applied in order to accelerate the sedimentation of the 3MS-MIO and their concentration.

[0016] After removal of the supernatant, the 3MS-MIO can be washed with aqueous solutions, particularly acidic or basic, to induce a pH change and release the target MIO molecule, on the one hand, and regenerate the (3MS-f) on the other hand, which can be recycled and reused for new MIO extractions.

[0017] These materials (3MS-f) advantageously make it possible to limit the quantities of solvent required for the isolation of target molecules, and consequently the cost of the drying step.

[0018] Furthermore, the selectivity of these materials for the MIO molecule that we wish to isolate can advantageously be modulated depending on the pore size and the functionalization of the materials (3MS-f)-

[0019] The invention thus relates firstly to a process for preparing a magnetic mesoporous material based on functionalized silica (3MS-f), said process comprising the steps of: i) Hydrolysis and precondensation, in an acid medium, of a silica precursor (SiO2) in the presence of a pore-forming compound of formula (POE) n - (POP)m-(POE) n in which:

[0020] - POE is a polyoxyethylene block,

[0021] - POP is a polyoxypropylene block,

[0022] - n is equal to 20 or 106 and - m is equal to 70; ii) Incorporation of silica-coated superparamagnetic iron nanoparticles into the precondensed mixture obtained in step i) and continuation of the condensation; ill) Removal of the pore-forming agent from the condensed structure obtained, whereby an organized magnetic mesoporous material based on silica (3MS) is obtained; iv) Functionalization of the material (3MS) obtained in the previous step, by covalent grafting of at least one reactive function capable of forming a weak bond with at least one organic molecule of interest (MIO), said weak bond being in particular chosen from electrostatic bonds between groups of opposite charges such as carboxylate / ammonium, phosphonate / ammonium, sulfonate / ammonium and hydrophobic bonds such as bonds between alkyl chains or between aromatic groups.v) Optionally, recovery of the functionalized silica-based magnetic mesoporous material (3MS-f) obtained in the previous step.

[0023] In embodiments of the method:

[0024] - the silica precursor is a compound comprising at least one alkoxysilane group, preferably a Si(OR)4 compound, with R, identical or different, representing a C1-C4 alkyl group.

[0025] - step ii) is carried out until a condensation rate of the silica precursor greater than or equal to 80% is obtained.

[0026] - step iii) is carried out by extraction of the pore-forming agent by solvent, in particular via a Soxhlet device.

[0027] - said at least one reactive function is grafted in step iv) by bringing the 3MS material into contact with a compound of formula:

[0028] (R 3 O)4-nSi-(LX)n (I)

[0029] In which:

[0030] X is a reactive function, notably chosen from

[0031] - a protic polar function chosen from an amine or a carboxylic acid, a phosphonic acid or a sulfonic acid, and the salts thereof or

[0032] - a hydrophobic group chosen from alkyl or aromatic groups, in particular phenyl groups L is a divalent spacer group, in particular chosen from a bond, a C1-C6 alkylene group, a C5-C7 arylene group, an aralkylene group, alkylarylene,

[0033] R 3 is H or a C1-C6 alkyl group; n is 1, 2 or 3.

[0034] According to a second aspect, the invention also relates to a magnetic mesoporous material based on functionalized silica (3MS-f), capable of being obtained by the process according to the invention.

[0035] According to a third aspect, the invention relates to a magnetic mesoporous material based on functionalized silica (3MS-f), characterized in that it comprises: a) A mesoporous material of type SBA-15 or SBA-16; b) One or more superparamagnetic iron particles, in particular coated with silica; c) At least one reactive function capable of forming a weak bond with at least one organic molecule of interest (MIO), said weak bond being in particular chosen from electrostatic bonds between groups of opposite charges, and hydrophobic bonds such as bonds between alkyl groups or between aromatic groups, in particular phenyl groups.

[0036] According to a fourth aspect, the invention relates to a magnetic mesoporous material based on non-functionalized silica (3MS) capable of being obtained according to steps i), ii) and ll) of the process according to the invention.

[0037] In embodiments of the functionalized (3MS-f) or non-functionalized (3MS) silica-based magnetic mesoporous materials according to the invention:

[0038] - the specific surface area SBET of the material (3MS-f), measured according to the BET method, is between 400 and 1000 m 2 / g, especially between 400 and 800 m 2 / g.

[0039] - the pore volume of the material (3MS-f) is between 0.7 and 1.1 mL / g, in particular between 0.8 and 1 mL / g.

[0040] - the average pore diameter is between 5 nm and 11 nm.

[0041] According to a fifth aspect, the invention relates to the use of a functionalized silica-based magnetic mesoporous material (3MS-f) according to the invention for isolating, concentrating and / or releasing an organic molecule of interest (MIO). In embodiments of this use, the organic molecule of interest (MIO) is selected from amino acids, polyphenols, polypeptides, proteins and oligosaccharides (OS).

[0042] According to yet another aspect, the invention relates to a method for isolating or concentrating an organic molecule of interest (MIO), comprising the steps of: a) Contacting the mixture comprising the MIO to be isolated or concentrated, with a material (3MS-f) according to the invention; b) Separating the mixture and recovering the material (3MS)-(MIO) formed in the previous step; and optionally c) Breaking the bond between the material (3MS) and the (MIO), whereby the (MIO) is released and recovered and the material (3MS-f) regenerated.

[0043] According to yet another aspect, the invention relates to a silica-based magnetic mesoporous material (3MS)-(MIO) obtainable according to steps a) and optionally b) of the method for isolating or concentrating an organic molecule of interest (MIO), according to the invention.

[0044] Other features, aspects, objects and advantages of the present invention will become even more apparent from the following description.

[0045] It is further specified that the expressions "between... and..." and "from... to..." used in this description must be understood as including each of the limits mentioned.

[0046] Brief description of the figures

[0047] Figure 1 is a schematic illustrating the synthesis of 3MS mesoporous silica

[0048] Figure 2 is a schematic illustrating the functionalization of 3MS mesoporous silica with a propylamine group.

[0049] Figure 3 represents the spectrum obtained by X-ray diffraction of a 3MS-f material according to the invention.

[0050] Figure 4 represents the thermogravimetric analysis (TGA) of a 3MS-f and 3MS material according to the invention

[0051] Detailed description

[0052] The invention is now described in more detail and in a non-limiting manner in the following description. By "organized mesoporous silica" or "organized mesoporous structure" is meant a structure consisting of an amorphous silica framework delimiting well-ordered channels and / or cavities of regular sizes. They are characterized by a pore size of 2 to 50 nm, as well as a high specific surface area, sometimes greater than 1000 m 2 .g' 1Organized mesoporous silicas are often synthesized using the cooperative self-assembly mechanism or CTM (Cooperative Templating Mechanism), the principle of which consists of hydrolyzing and then condensing an inorganic precursor (silane) around surfactant micelles in aqueous solution. Depending on the nature of the surfactant used (ionic or non-ionic) and the reaction medium (acidic or basic) in which the synthesis takes place, different families of materials (M41 S, SBA-n, HMS, MSU, etc.) can be obtained.

[0053] The materials (3MS) or (3MS-f) according to the invention belong to the SBA-n family (D. Zhao, J. Feng, Q. Huo, N. Melosh, GH Fredrickson, BF Chmelka, GD Stucky. Science. 1998, 279, 548) and in particular to the SBA-15 or SBA-16 type SMO. This family has larger pores and thicker walls which give it greater hydrothermal stability than the M41 S family generally used.

[0054] By “mesoporous material” is meant a material including pores with a diameter between 2 nm and 50 nm, in particular between 2 and 30 nm.

[0055] By "alkyl" is meant a saturated, linear or branched hydrocarbon group of formula CnH2n+i, where n represents the number of carbon atoms.

[0056] Process for preparing a material (3MS-f)

[0057] According to a first aspect, the invention relates to a process for preparing a magnetic mesoporous material based on functionalized silica (3MS-f), said process comprising the steps of: i) Hydrolysis and precondensation, in an acidic aqueous medium, of a silica precursor (SiO2) in the presence of a pore-forming compound of formula (POE) n -(POP)m-(POE) n in which:

[0058] POE is a polyoxyethylene block, POP is a polyoxypropylene block, n is equal to 20 or 106 and m is equal to 70; ii) Incorporation of silica-coated superparamagnetic iron oxide nanoparticles into the precondensed mixture obtained in step i) and continuation of the condensation; ll) Removal of the pore-forming agent from the condensed structure obtained, whereby an organized silica-based magnetic mesoporous material (3MS) is obtained; iv) Functionalization of the material (3MS) obtained in the previous step, by covalent grafting of at least one reactive function capable of forming a weak bond with at least one organic molecule of interest (MIO), said weak bond being in particular chosen from electrostatic bonds between groups of opposite charges and hydrophobic bonds such as bonds between aromatic groups, or alkyl chains;v) Optionally, recovery of the functionalized silica-based magnetic mesoporous material (3MS-f) obtained in the previous step.;

[0059] By "aromatic group" is meant a system of mono- or bicyclic, substituted or unsubstituted hydrocarbon aromatic ring(s), having in particular from 6 to 12 carbon atoms in the ring. Examples include phenyl and naphthyl. Preferred aryl groups include unsubstituted or substituted phenyl and naphthyl groups. The definition of the term "aryl" encompasses fused ring systems, including, for example, ring systems in which an aromatic ring is fused to a cycloalkyl ring. Examples of such fused ring systems include, for example, indane, indene and tetrahydronaphthalene.

[0060] By "alkyl chain" or "alkyl group" is meant a straight or branched chain of formula -CnH2n+i preferably having from 6 to 12 carbon atoms, such as 3-methylpentyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, hexyl, octyl, etc.

[0061] [Step i)]

[0062] The pore-forming agent used in step i) is either the triblock copolymer Pluronic® P123 of formula POE20POP70POE20 or Pluronic® F127 (also called Poloxamer 407) of formula POE106POP70POE106.

[0063] In particular, as reported in the literature, Pluronic® P123 of formula allows the synthesis of Organized Mesoporous Structures (OMS) of SBA-15 type with 2D-hexagonal structure (P6mm) while Pluronic® F127 allows access to SMO structures of SBA-16 type with 3D-cubic structure (Im3m).

[0064] SBA-15 type SMOs reported in the literature generally have large pores ranging from 50 to 300 Å, perfectly calibrated, and modulated by playing on the presence of pore expanders, the synthesis conditions, a specific surface area that can reach up to 1000 m 2 / g and thick walls (several nanometers) which gives the material good hydrothermal stability.

[0065] SBA-16 type SMOs reported in the literature possess volumetric properties similar to those of SBA-15.

[0066] Step i) of hydrolysis and precondensation comprises the steps of:

[0067] 11) dispersion of the pore-forming agent in an acid medium, in particular at a temperature between 30 and 50°C;

[0068] 12) addition, dispersion and precondensation of the silica precursor in the mixture obtained in step ii), in particular at a temperature between 90°C and 150°C.

[0069] Step ii) is carried out in particular at an acidic pH. The concentration of strong acid can be between 1 mol / L and 2 mol / L, in particular around 1.6 mol / L.

[0070] The acid used in step ii) is in particular a mineral acid, such as hydrochloric acid.

[0071] According to embodiments, the molar concentration of the pore-forming agent in the water is between 3 mmol / L and 8 mmol / L, in particular between 4.5 mmol / L and 6 mmol / L.

[0072] Step ii) aims to solubilize the pore-forming agent in the aqueous solution. This step is typically carried out with stirring and / or for a duration tii of between 1 and 3 hours.

[0073] Step i2) comprises the addition of the silica precursor to the pore-forming agent solution obtained in step ii). This addition is generally carried out with stirring.

[0074] The silica precursor may be a compound comprising at least one alkoxysilane group, preferably a Si(OR)4 compound, with R, identical or different, representing a C1-C4 alkyl group. Examples of silica precursors include tetraethylorthosilicate (TEOS) and tetramethoxysilane (TMOS). The molar ratio of the silica precursor to the pore-forming agent may vary depending on the pore size, pore volume and / or specific surface area desired. Preferably, it is between 50 and 200, especially between 50 and 100.

[0075] Step i2) can be carried out until the formation of a dispersed solid phase, visible to the naked eye, corresponding to the formation of suspended silica particles resulting from the hydrolysis and condensation of the precursor and resulting in opacification of the reaction mixture. The evolution of the turbidity of the mixture can also be monitored continuously by spectrophotometry, for example by turbidimetry or opacimetry.

[0076] Alternatively, step i2) can be carried out until a condensation rate of the silica precursor of at least 40% is obtained.

[0077] The term "precursor condensation rate" means the molar ratio of the number of condensed bonds to the number of condensable bonds. This condensation rate can be monitored and calculated by NMR.

[0078] The inventors were indeed able to observe that it was important not to add the superparamagnetic iron oxide particles before precondensation of the silica precursor, so as not to compromise the formation of the organized mesoporous structure of the SBA-15 or SBA-16 type. Thus, they were able to observe that when these iron oxide particles were added at the same time as the silica precursor to the aqueous solution containing the pore-forming agent P123, the solid phase obtained at the end of the condensation of the precursor did not have an organized mesoporous structure of the SBA-15 type.

[0079] Furthermore, it is also preferable to introduce the superparamagnetic iron oxide particles at a not too advanced stage of the condensation of the silica precursor so as to promote a homogeneous distribution of the particles within the organized mesoporous structure.

[0080] Typically, step i2) is carried out for a duration ti2 of between 1 and 3 hours.

[0081] [Step ii)]

[0082] Step ii) corresponds to the addition of superparamagnetic iron oxide particles (FesC).

[0083] These iron oxide particles can be prepared according to methods well known in the state of the art, in particular according to the process described in Massart et al., Preparation of aqueous magnetic liquids in alkaline and acidic media, IEEE Transactions on Magnetics, Vol. Mag-17, No. 2, March 1981.

[0084] Superparamagnetic iron oxide particles (FesC) are generally about 5 to 10 nm in size. They are present in the reaction medium in the form of aggregates whose size is less than 100 nm.

[0085] The particles used in the process are previously coated with a layer of silica, so as to protect them from the acidic conditions required for the synthesis of the organized mesoporous structure. This silica coating can be obtained using conventional methods such as that described in Preparation and Properties of Uniform Coated Colloidal Particles. VII. Silica on Hematite, Journal of Colloid and Interface Science, Vol. 150. No. 2, May 1992.

[0086] The process for preparing the silica-coated superparamagnetic iron oxide particles may in particular comprise the steps of:

[0087] - Contacting an aqueous suspension of superparamagnetic iron oxide particles with ammonia;

[0088] - Addition of a silica precursor to the mixture obtained in the previous step; and

[0089] - Recovery of the superparamagnetic iron particles coated with silica thus obtained.

[0090] The thickness of the silica layer formed around the superparamagnetic iron particles can vary depending in particular on the molar ratio between the superparamagnetic iron oxide particles and the silica precursor.

[0091] In embodiments, the superparamagnetic iron nanoparticle aggregates are coated with a silica layer with a thickness of between 1 and 10 nm, in particular between 2 nm and 5 nm.

[0092] In embodiments, the silica-coated superparamagnetic iron nanoparticles have a size between 5 and 10 nm and the aggregates have a size less than 120 nm, generally on the order of 100 nm.

[0093] Advantageously, the silica coating on the iron oxide particles helps preserve the magnetic properties of the particles during the process, which notably uses particularly acidic conditions, capable of dissolving the iron oxide nanoparticles.

[0094] Furthermore, it helps promote the incorporation and fixation of iron oxide particles within the organized network of the mesoporous structure. As a result, the iron oxide particles are less exposed and therefore less likely to be degraded by the surrounding environment, compared to the configuration where the iron oxide nanoparticles would only be attached to the surface of the mesoporous structure. Thus, the magnetic properties of the 3MS material are better preserved over time.

[0095] Step ii) can be carried out at a temperature TÜ between 70°C and 100°C, in particular at 80°C.

[0096] The condensation step in step ii) continues until a condensation rate of the silica precursor greater than or equal to 60% is obtained.

[0097] The material (3MS) thus obtained can then be recovered. It is generally in the form of particles, in particular micro- or nanoparticles.

[0098] In embodiments, prior to step iii), the suspension containing the material (3MS) obtained in step ii) is neutralized and washed, in particular until a conductivity close to that of water is obtained, typically less than 10 microsiemens / cm.

[0099] [Step iii)]

[0100] Step iii) comprises the removal of the pore-forming agent from the resulting condensed structure.

[0101] This elimination is preferably carried out by extraction of the pore-forming agent by solvent, in particular via a Soxhlet device.

[0102] Unlike calcination extraction methods, solvent extraction advantageously preserves the superparamagnetic iron oxide particles from possible degradation, and extracts the pore-forming agent without degrading it, so that it can be reused / recycled to prepare new 3MS or 3MS-f materials.

[0103] Thus, according to one embodiment, the pore-forming agent in solution in the extraction solvent is recovered, and in particular recycled by implementation in step i) of the process according to the invention.

[0104] [Step iv)]

[0105] Step iv) comprises the functionalization of the 3MS material obtained by at least one reactive function. The latter is in particular chosen so as to be able to form a weak bond, of the electrostatic or hydrophobic bond type, with at least one of the functions carried by the molecule of interest, for example a carboxylic acid or amine function. According to embodiments, in step iv), said at least one reactive function grafted onto the 3MS material obtained in step iii) is chosen from:

[0106] - a polar protic group chosen from an amine or a carboxylic acid, a phosphonic acid or a sulfonic acid,

[0107] - a hydrophobic group chosen from aromatic groups, in particular phenyl groups, or alkyl groups;

[0108] Said at least one reactive function can be grafted in step iv) by bringing the 3MS material into contact with a compound of formula:

[0109] (R 3O)4-nSi-(LX)n (I)

[0110] In which:

[0111] X is a reactive function, notably chosen from:

[0112] - a protic polar function chosen from an amine or a carboxylic acid, a phosphonic acid or a sulfonic acid, or a salt thereof, or

[0113] - a hydrophobic group chosen from aromatic groups, in particular phenyl groups, or alkyl groups;

[0114] L is a divalent spacer group, in particular chosen from a bond, a C1-C6 alkylene group, a C5-C7 arylene group, an aralkylene group, alkylarylene,

[0115] R 3 is H or a C1-C6 alkyl group; n is 1, 2 or 3.

[0116] Thus, the functionalization step can be carried out by condensation of a compound comprising an alkoxysilane function, such as a compound of formula (I) with the silanol functions present on the surface of the 3MS material.

[0117] This functionalization can be carried out in particular in a suitable organic solvent, for example toluene. It is generally carried out at a temperature compatible with the molecule carrying the reactive function that one wishes to graft, that is to say a temperature that makes it possible to avoid the degradation of this molecule and lower than the boiling point of the solvent. For example, the functionalization can be carried out at a temperature that can be between 70°C and 100°C.

[0118] [Step v)]

[0119] Step v) includes the recovery of the functionalized material (3MS- f) obtained in the previous step.

[0120] Material (3MS-f) can be washed with alcohol and then dried. Materials (3MS-f) and (3MS)

[0121] According to a second aspect, the invention relates to a magnetic mesoporous material based on functionalized silica (3MS- / ), capable of being obtained by the method according to the invention.

[0122] According to yet another aspect, the invention relates to a magnetic mesoporous material based on functionalized silica (3MS- / ), characterized in that it comprises: a) An organized mesoporous structure of the SBA-15 or SBA-16 type; b) One or more superparamagnetic iron particles, in particular coated with silica; c) At least one reactive function capable of forming a weak bond with at least one organic molecule of interest (MIO), said weak bond being in particular chosen from

[0123] - an electrostatic bond based on carboxylate / ammonium, phosphonate / ammonium, or sulfonate / ammonium interactions

[0124] - a hydrophobic bond based on interactions between aromatic groups, notably phenyl or alkyl groups.

[0125] According to yet another aspect, the invention relates to a silica-based magnetic mesoporous material (3MS) obtainable according to steps i), ii), iii) and iv) of the process according to the invention. This material is in particular useful as an intermediate for the preparation of the materials (3MS- / ) according to the invention.

[0126] Advantageously, the characteristics of these materials, such as functionalization, porosity, pore volume and / or specific surface area can be modulated according to the target molecule that one wishes to isolate and / or the extraction medium in which it is found, in particular by varying the synthesis conditions of the process according to the invention.

[0127] The specific surface area SBET of the material (3MS- / ) or (3MS), measured according to the BET method, can be between 400 and 1000 m 2 / g, especially between 400 and 800 m 2 / g.

[0128] The pore volume of the material (3MS- / ) or (3MS) can be between 0.4 and 1.1 mL / g, in particular between 0.8 and 1 mL / g.

[0129] The average pore diameter of the material (3MS- / ) or (3MS) can be between 5 nm and 11 nm. This diameter can be measured using methods well known in the field of mesoporous materials, in particular by nitrogen physisorption. Use of the materials (3MS-f) and (3MS)

[0130] According to yet another aspect, the invention relates to the use of a functionalized silica-based magnetic mesoporous material (3MS- / ) according to the invention for isolating and / or concentrating an organic molecule of interest (MIO).

[0131] The organic molecule of interest (OMI) to be isolated and / or concentrated can be a molecule of plant origin, for example from co-products of the agri-food industry or even from wine or wine-making co-products.

[0132] The use of materials (3MS-f) can thus advantageously contribute to the recovery of industrial co-products.

[0133] The organic molecule of interest (OMI) to be isolated and / or concentrated may be, for example, a medicinal or cosmetic substance.

[0134] It can be chosen from amino acids, polyphenols, polypeptides, proteins, oligosaccharides (OS).

[0135] Process for isolating and / or concentrating an organic molecule of interest (MIO)

[0136] According to yet another aspect, the invention relates to a method for isolating or concentrating an organic molecule of interest (MIO), comprising the steps of: a) Contacting the mixture comprising the MIO to be isolated and / or concentrated, with a material (3MS-f) according to the invention, so as to form a material (3MS)-(MIO); b) Separating the mixture and recovering the material (3MS)-(MIO) formed in the previous step; and c) Breaking the bond between the material (3MS) and the (MIO), whereby the (MIO) is released and recovered and the material (3MS- / ) regenerated.

[0137] [(3MS-f) functionalized with a protic polar function]

[0138] According to one embodiment, the material (3MS- / ) is functionalized with a protic polar function.

[0139] Step a) is then generally carried out in an aqueous medium, under pH conditions favorable to the formation of an electrostatic bond between the reactive function of the material (3MS- / ) and at least one function of the organic molecule of interest.

[0140] Step b) can advantageously be carried out by applying an external magnetic field. In this context, step c) can be carried out by adding an acidic or basic solution so as to modify the pH of the aqueous solution and break the electrostatic bond between the material (3MS) and the molecule of interest (MIO).

[0141] [(3MS-f) functionalized with a hydrophobic group]

[0142] According to another embodiment, the material (3MS-f) is functionalized with a hydrophobic group.

[0143] Step a) is then generally carried out in an aqueous medium. MIOs having a hydrophobic reactive function will react with a hydrophobic reactive function of the material (3MS-f) to form hydrophobic bonds.

[0144] Step b) can be advantageously carried out by applying an external magnetic field.

[0145] In this context, step c) can be carried out by immersing the recovered material (3MS-f) in an organic solution, in particular an alcohol or a ketone so as to break the hydrophobic bond between the material (3MS) and the molecule of interest (MIO).

[0146] Magnetic mesoporous material based on silica (3MS)-(MIO) obtainable according to the process of the invention

[0147] According to yet another aspect, the invention relates to a magnetic mesoporous material based on silica (3MS)-(MIO) capable of being obtained according to steps a) and optionally b) of the method according to the invention.

[0148] This material may be particularly useful for the storage and / or release of the MIO molecule.

[0149] Example 1: Preparation of a material (3MS-f): (3MS-NH2)

[0150] Step 1: Synthesis of superparamagnetic iron oxide nanoparticles: FesO4

[0151] Solution A: 10 mL of a 0.150 M aqueous solution of iron(III) chloride, 6H2O are prepared in a Schlenk tube under nitrogen flow.

[0152] Solution B: 10 mL of a 0.075 M aqueous solution of iron(ll) chloride, 4H2O are prepared in a Schlenk tube under nitrogen flow. With mechanical stirring, both solutions A and B are added simultaneously to a three-necked flask, under nitrogen flushing and in the presence of a condenser. The mixture is brought to 80°C. At this temperature, 20 mL of 2 mol / L ammonia are added. The mixture is stirred for 2 hours at 80°C. The pH is approximately 12 (12+ / - 0.3).

[0153] The suspension is washed by centrifugation / redispersion several times so that the conductivity of the solution is less than 10 pS / cm.

[0154] The pH of the suspension is then lowered to pH 3 by dropwise addition of 2 M HCl. The size of the iron oxide aggregates is approximately 100 nm (measured by DLS, Malvern, Nano ZS, UK).

[0155] Step 2: Coating of iron oxide nanoparticles with a layer of silica: FesO4@SiO2

[0156] 200 mg of iron oxide are taken from the suspension at pH 3 (volume taken approximately 20 mL).

[0157] The collected suspension is dispersed in an EtOH / water mixture (150 mL / 40 mL) for 30 min by mechanical stirring.

[0158] 3 mL of 2 mol / L ammonia are then added to the suspension dropwise and the whole is stirred for 15 min.

[0159] 300 mg of TEOS (silicon tetraethoxide) are added dropwise to the previous mixture at room temperature. The whole is stirred for 24 hours at room temperature.

[0160] The suspension is then washed several times with an ethanol / water mixture (250 mL / 250 mL).

[0161] The size of iron oxide aggregates is about 100 nm (measured by DLS, Malvern, Nano ZS, UK).

[0162] Step 3: Synthesis of magnetic mesoporous silica: FesO4@SiO2 / SBA15

[0163] Step 1: Synthesis Preparation 7: 1.5 g of copolymer P123 are dissolved in 40 mL of 2 mol / L HCl by mechanical stirring at 40°C for 2 hours.

[0164] 3.12 g of TEOS are added dropwise to the solution under mechanical stirring. The solution is brought to 100°C in a glass flask.

[0165] Preparation 2: 200 mg of FesC fSJSiC are dispersed in 9 mL of water and 1 mL of 1 mol / L HCl and stirred for 30 min at room temperature.

[0166] After placing preparation 1 at 100°C for 2 hours (obtaining a milky solution), preparation 2 is added. The mixture is then left at 100°C for a further 22 hours.

[0167] The pH of the mixture is raised to pH 7 by adding sodium hydroxide (NaOH, 1 mol / L). The suspension is then washed several times by centrifugation / redispersion cycles until the conductivity of the suspension is close to that of pure water (conductivity < 10 pS / cm).

[0168] Step 2: Extraction of the copolymer

[0169] The P123 copolymer is extracted from the silica particles in the presence of organic solvent (ethanol) for 48 hours (Soxhlet method). The sample is then dried in an oven overnight at 80°C.

[0170] The sample is then characterized by nitrogen physisorption at 77K (Micromeritics ASAP 2020, Nocross, GA). The sample is degassed beforehand at 363K under vacuum. The specific surface area of ​​the sample is calculated using the BET method in a pressure range P / Po = 0.06 to 0.25. The pore size distribution and pore volume are obtained with the BJH method using an adsorbed nitrogen volume at P / Po = 0.75.

[0171] Physicochemical properties of silica particles: BET surface area: ~ 800 m 2 / g; pore volume: ~ 1 g / mL; pore diameter: ~ 5.3 nm.

[0172] Step 4: Functionalization of magnetic mesoporous silica 200 mg of FesC fSJSiC / SBA15 are dispersed in 10 mL of anhydrous toluene at 80°C. 2 mL of aminopropyltriethoxysilane (APTES, Sigma-Aldrich) are then added dropwise. The mixture is kept at 80°C for 24 hours then washed 3 times in ethanol and dried in an oven at 60°C for 24 hours. The sample is then characterized by nitrogen physisorption at 77K (Micromeretics ASAP 2020, Nocross, GA). The sample is degassed beforehand at 363 K under vacuum. The specific surface area of ​​the sample is calculated using the BET method in a pressure range P / Po = 0.06 to 0.25. The pore size distribution and pore volume are obtained with the BJH method using an adsorbed nitrogen volume at P / P0 = 0.75.For more information on the BJH method, please refer to the article: BARRETT, EP; JOYNER, LG; HALENDA, PP “The Determination of Pore Volume and Area Distributions in Porous Substances I Computations from Nitrogen Isotherms”, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, Year 1951, Volume 73 Issue 1 Page 373-380.

[0173] Physicochemical properties of mesoporous silica particles with amine functions: BET surface area: ~ 700 m 2 / g; pore volume: ~ 0.9 g / mL; pore diameter: ~ 5 nm.

[0174] Example 2: Adsorption / desorption of phenylalanine

[0175] Adsorption and desorption tests of a model molecule, phenylalanine (PhA) (one of the essential amino acids), were carried out to test 3MS-NH2 obtained in Example 1.

[0176] Adsorption test (PhA@3MS-NH2): 4 ml of a 0.8 g / l phenylalanine solution was mixed with 50 mg of 3MS-NH2 at neutral pH. After 24 h of mixing, the solid was separated from the supernatant using a magnet. The supernatant was analyzed by dynamic light scattering (DLS, Malvern Nano ZS, UK) to verify the absence of 3MS-NH2 particles. The liquid phase was determined by UV-visible spectrophotometry (Shimadzu, UV2550, Japan): approximately 79% of phenylalanine was adsorbed. Desorption test: 50 mg of 3MS-NH2 on which phenylalanine was adsorbed (PhA@3MS-NH2) was dispersed in 4 mL of water at pH 2. After 24 h of mixing, the solid phase was separated from the liquid phase using a magnet. The supernatant was analyzed by DLS (Malvern, Nano ZS, UK) to verify that there were no more particles in the liquid phase. The liquid phase was analyzed by UV-visible spectrophotometry: approximately 93% of the initially adsorbed PhA was desorbed.

Claims

Demands 1. Process for preparing a functionalized silica-based magnetic mesoporous material 3MS-f, said process comprising the steps of: i) Hydrolysis and precondensation, in acidic medium, of a silica precursor (SiO2) in the presence of a porous compound of formula (POE) n - (POP)m-(POE) n in which: POE is a polyethylene block. POP is a polyoxypropylene block, n is equal to 20 or 106 and m is equal to 70; ii) Incorporation of silica-coated superparamagnetic iron nanoparticles into the pre-condensed mixture obtained in step i) and further condensation; ill) Removal of the porogen from the condensed structure obtained, thereby obtaining an organized magnetic mesoporous material based on silica 3MS; iv) Functionalization of the 3MS material obtained in the previous step, by covalent grafting of at least one reactive function capable of forming a weak bond with at least one organic molecule of interest (OMI), said weak bond being chosen in particular from electrostatic bonds between oppositely charged groups such as carboxylate / ammonium, phosphonate / ammonium, sulfonate / ammonium and hydrophobic bonds such as bonds between alkyl chains or between aromatic groups.v) Optionally, recovery of the functionalized 3MS-f silica-based magnetic mesoporous material obtained in the previous step.

2. A process according to any one of the preceding claims, wherein the silica precursor is a compound comprising at least one alkoxysilane group, preferably a Si(OR)4 compound, with R, identical or different, representing a C1-C4 alkyl group.

3. A process according to any one of the preceding claims, wherein step ii) is carried out until a condensation rate of the silica precursor is greater than or equal to 80%.

4. A method according to any one of the preceding claims, wherein step iii) is carried out by solvent extraction of the porogenous agent, in particular via a Soxhlet device.

5. A method according to any one of the preceding claims, wherein said at least one reactive function is grafted in step iv) by contacting the 3MS material with a compound of formula: (R 3 O)4-nSi-(LX)n (I) In which: X is a reactive function, notably chosen from - a polar protic function chosen from an amine or a carboxylic acid, a phosphonic acid or a sulfonic acid, and salts thereof or - a hydrophobic group chosen from among alkyl or aromatic groups, particularly phenyl groups L is a divalent spacer group, notably chosen from among a bond, an alkylene group in C1-C1, an arylene group in C5-C7, an aralkylene group, alkylarylene, R 3 is H or an alkyl group in C1-C6; n is 1, 2 or 3.

6. Functionalized silica-based magnetic mesoporous material 3MS-f, which can be obtained by the process as defined in claims 1 to 5.

7. 3MS-f functionalized silica-based magnetic mesoporous material, characterized in that it comprises: a) A mesoporous material of type SBA-15 or SBA-16; b) One or more silica-coated superparamagnetic iron particles; c) At least one reactive function capable of forming a weak bond with at least one organic molecule of interest (OMI), said weak bond being in particular selected from electrostatic bonds between oppositely charged groups, and hydrophobic bonds such as bonds between alkyl groups or between aromatic groups, in particular phenyl groups.

8. Non-functionalized silica-based magnetic mesoporous material 3MS obtainable according to steps i), ii) and ill) of the process as defined in claims 1 to 5.

9. A silica-based magnetic mesoporous material functionalized with 3MS-f or non-functionalized with 3MS according to any one of claims 6 to 8, wherein the specific surface area SBET of the 3MS-f material, measured according to the BET method, is between 400 and 1000 m² 2 / g, particularly between 400 and 800 m 2 / g.

10. Magnetic mesoporous material based on silica 3MS or 3MS-f, according to any one of claims 6 to 9, wherein the pore volume of the material is between 0.4 and 1.1 mL / g, in particular between 0.8 and 1 mL / g.

11. Magnetic mesoporous material based on silica 3MS or 3MS-f, according to any one of claims 6 to 10, wherein the average pore diameter is between 5 nm and 11 nm.

12. Use of a functionalized 3MS-f silica-based magnetic mesoporous material according to any one of claims 6, 7, and 9 to 11 to isolate, concentrate and / or release an organic molecule of interest (MIO).

13. Use according to claim 12, wherein the organic molecule of interest (OMI) is selected from amino acids, polyphenols, polypeptides, proteins, oligosaccharides (OS).

14. A process for isolating or concentrating an organic molecule of interest (MIO), comprising the steps of: a) Contacting the mixture comprising the MIO to be isolated or concentrated with a 3MS-f material as defined in any one of claims 6, 7, and 9 to 11; b) Separating the mixture and recovering the 3MS-(MIO) material formed in the previous step; and optionally c) Breaking the bond between the 3MS material and the (MIO), thereby releasing and recovering the (MIO) material and regenerating the (3MS- / ) material.

15. Magnetic mesoporous material based on silica 3MS-(MIO) capable of being obtained according to steps a) and optionally b) of the process according to claim 14.

Images