Adsorbent material for perfluoroalkyl and polyfluoroalkyl substances

Abstract

The present invention relates to an adsorbent material comprising a support consisting of activated carbon or nonwoven nanofibers, said support being impregnated with metal oxide nanoparticles, and said nanoparticles being functionalized by covalent bonding with polyfluoro and / or polyalkyl phosphonic ligands.

Description

[0001] DESCRIPTION

[0002] Material adsorbent of perfluoroalkyl and polyfluoroalkyl substances

[0003] FIELD OF INVENTION

[0004] The general field of the invention is that of materials adsorbing perfluoroalkyl and polyfluoroalkyl substances (PFAS), and their use for the purification of water and gases contaminated by said substances.

[0005] STATE OF THE ART

[0006] Perfluoroalkyl and polyfluoroalkyl substances (designated by their acronym PFAS) are a group of synthetic organofluorine compounds containing one or more per- or poly-fluoroalkyl functional groups. This group of compounds includes a large number of substances, among them perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS).

[0007] These fluorinated compounds have been widely used in various industrial applications and everyday consumer products: textiles, food packaging, firefighting foams, refrigerants, non-stick coatings, cosmetics, medical devices, plant protection products, etc. These compounds have achieved widespread success due to their excellent surfactant properties, their key role as precursors of fluorinated polymers, and their chemical durability, due to the strength of the carbon-fluorine bonds they contain.

[0008] Unfortunately, these same properties make PFAS resistant to degradation in the environment, hence their nickname "forever pollutants." It is estimated that most drinking water today contains PFAS.

[0009] However, studies have established a link between the accumulation of PFAS in human bodies and various adverse effects on human health, including high cholesterol levels, an increased risk of developing kidney or testicular cancer, and the onset of thyroid diseases.

[0010] Thus, the elimination of PFAS has become a public health priority. To date, no industrially scalable technology exists that can destroy and completely eliminate them. Current development efforts are focused on techniques for isolating them in order to decontaminate water and gas.

[0011] Several technologies have been developed to remove PFAS compounds from the environment and drinking water. These include reverse osmosis and nanofiltration. Other technologies utilize adsorbent materials such as activated carbon and ion-exchange resins. Activated carbon is known for its effectiveness in adsorbing per- and polyfluoroalkyl substances (PFAS). The adsorption mechanism of activated carbon relies primarily on physicochemical interactions, such as van der Waals forces and hydrophobic forces, as well as weaker chemical interactions. The PFAS adsorption performance of activated carbon is influenced by several parameters, including the molecular weight and hydrophobicity of the target molecules.

[0012] In general, low molecular weight PFAS, such as perfluoropentanic acid (PFPEA), are less well adsorbed compared to higher molecular weight PFAS, such as perfluorooctanoic acid (PFOA).

[0013] The hydrophobicity of PFAS molecules also plays a crucial role in their adsorption. More hydrophobic molecules, characterized by longer fluorinated chains, exhibit a greater affinity for the hydrophobic surfaces of activated carbon, thus promoting better adsorption.

[0014] In conclusion, activated carbon effectively adsorbs PFAS with long carbon chains (more than 8 carbons) and nonpolar functional groups. Therefore, other adsorbent materials need to be developed to enable the adsorption of PFAS with short carbon chains and / or hydrophilic / polar functional groups.

[0015] The design of new adsorbent materials, based on porous supports functionalized by specific ligands, is currently under study.

[0016] The article (STEBEL, 2019) describes adsorbent materials composed of a porous silica resin (SOMS) functionalized by the bonding of fluorophilic or fluoroalkyl amide groups (F-SOMS) or cationic quaternary groups (QA-SOMS), or in combination with a cationic polymer (Poly-SOMS).

[0017] The article (GAGLIANO, 2020) compares the effects of different adsorbent supports: carbon, ion exchange resins, or metal oxide nanoparticles, which can be functionalized with fluorinated groups.

[0018] International application WO 2020 / 206317 describes adsorbent supports treated with metal oxides, intended to capture perfluoroalkyl substances (PFAS) contained in liquids or gases.

[0019] International application WO 2022 / 109392 describes an apparatus for trapping PFAS. Said apparatus contains adsorbent particles containing at least one compound selected from activated carbon and metal oxides, or a combination of the two.

[0020] International application WO 2023 / 107629 describes an adsorbent material for binding PFAS. This material consists of ceramic particles functionalized by covalent bonding of a functional group to their surface, and also contains a metal selected from silicon (Si), aluminum (Al), titanium (Ti), or zinc (Zn). This application relates to novel adsorbent materials that exhibit improved PFAS adsorption efficiency compared to activated carbon, and furthermore, better selectivity for adsorbing low molecular weight PFAS and / or PFAS with hydrophilic groups.

[0021] DESCRIPTION OF THE INVENTION

[0022] The present invention relates to an adsorbent material comprising a support made of activated carbon or non-woven nanofibers, said support being impregnated with metal oxide nanoparticles, and said nanoparticles being functionalized by covalent bonding with polyfluorinated and / or polyalkylated phosphonic ligands.

[0023] The invention also relates to methods for preparing said adsorbent material.

[0024] According to a first aspect, the process for preparing the adsorbent material according to the invention comprises the following steps: a) immersion of the support in a suspension comprising metal oxide nanoparticles in a solvent, preferably ethanol, to obtain a "loaded support"; b) drying of the loaded support in two sub-steps, first at a temperature between 100°C and 120°C, then at a temperature between 200°C and 240°C; c) immersion of the loaded and dried support in a suspension containing polyfluorinated or polyalkylated phosphonic ligands; d) drying of the support obtained in step (c) at a temperature between 50 and 110°C, thereby enabling the functionalization of the metal oxide nanoparticles; e) washing of the adsorbent material obtained with a suitable solvent, in particular with deionized water.

[0025] According to a second aspect, the process for preparing the adsorbent material according to the invention comprises the following steps: a) preparation of a suspension comprising metal oxide nanoparticles and polyfluorinated and / or polyalkylated phosphonic ligands in a solvent; b) optionally, vacuum drying at 40°C under rotation for evaporation of the solvent; c) immersion of a support in a suspension containing the metal oxide nanoparticles functionalized with said ligands, then continuous homogenization by rotation; d) drying of the loaded support obtained in step (c), preferably at a temperature between 50 and 110°C; e) washing of the adsorbent material obtained with a suitable solvent, in particular with deionized water.

[0026] According to a third aspect, in the case where the support is made of non-woven polymer nanofibers, the process for preparing the adsorbent material according to the invention comprises the following steps: a) preparation of a suspension comprising metal oxide nanoparticles and polyfluorinated and / or polyalkylated ligands in a solvent; b) optionally, vacuum drying at 40°C under rotation, for evaporation of the solvent; c) homogenization of the polymer in solution using a mixer, and addition of the metal oxide nanoparticles functionalized with polyfluorinated and / or polyalkylated phosphonic ligands; d) electrospinning of the polymer loaded with the functionalized nanoparticles obtained in step (c) to obtain nanofibers; e) drying of the nanofibers obtained in step (d), preferably at a temperature between 120 and 170°C, to obtain cross-linking of the polymer;f) washing the resulting adsorbent material with a suitable solvent, in particular deionized water.;

[0027] The invention also relates to a method for capturing perfluoroalkyl and polyfluoroalkyl substances (PFAS) comprising bringing a liquid or gas likely to contain PFAS into contact with the adsorbent material as defined above, or as obtained by any of the methods described above.

[0028] Finally, the invention relates to the use of the adsorbent material according to the invention, or as obtained by one of the processes according to the invention, to capture perfluoroalkyl and polyfluoroalkyl substances (PFAS) present in a liquid or a gas.

[0029] DESCRIPTION OF THE FIGURES

[0030] Figure 1 shows the quantification of the zirconium dioxide (ZrO2) content of the loaded activated carbon support (after step (b)) by thermogravimetric analysis. This support was loaded with two quantities of ZrO2: 20% by weight (CA-ZrO2-01, dashed line) and 2% by weight (CA-ZrO2-03, solid line), relative to the total weight of the loaded support. At this concentration, the results reveal a residual content of 2.6% by weight, very close to the theoretical target value of 2%. This proximity between the measured and theoretical values ​​confirms efficient and controlled fixation of zirconium dioxide in the activated carbon.

[0031] Figure 2 shows the specific surface area of ​​activated carbon loaded with 20% by weight of ZrC>2 (point at 20%) and with 2% by weight of ZrC>2 (point at 2%). The graph also shows the initial specific surface area (before loading) at 0%.

[0032] Figure 3 illustrates the adsorption rate (%) of the PFOA compound by functionalized ZrC>2 metal oxide (left, 96%) and by uncharged activated carbon (right, 75%).

[0033] Figure 4 illustrates the performance tests performed with functionalized ZrC>2 metal oxide used for PFOA adsorption. 1) Percentage of PFOA adsorption as a function of the initial PFOA concentration (54, 140, and 300 ppm = mg L⁻¹) -1 ) simulating different pollution conditions; 2) Recovery rate (%) as a function of the initial concentration of PFAS (Co, in ppm).

[0034] Figure 5 illustrates the measurement of the adsorption isotherm Qmax (mmol / g) of the functionalized metal oxide (grey squares) in parallel with the Langmiur model (black triangles).

[0035] Figure 6 illustrates the adsorption selectivity of virgin (uncharged) activated carbon for 14 different PFAS: PFBA, PFPeA, PFHxA, PFBS, PFHpA, PFPeS, PFOA, PFNA, PFHxS, PFHpS, PFDA, PFOS, PFUnDA, and PFUnDS. The breakthrough percentage represents the percentage of PFAS compound released as a function of the number of washes (volume of water added / volume of activated carbon). The breakthrough percentage must be less than 10% for PFAS adsorption to be considered satisfactory. This figure illustrates that uncharged activated carbon only effectively adsorbs high molecular weight PFAS (C8 to C11).

[0036] Figure 7 illustrates the adsorption selectivity of the functionalized metal oxide. It represents the adsorption rate of PFOA (at C8), PFPeA (at C5) and an organic pollutant (bisphenol A) by virgin activated carbon (left) and by the functionalized ZrCh metal oxide (right).

[0037] DETAILED DESCRIPTION OF THE INVENTION

[0038] The adsorbent material according to the invention is innovative in that it contains specific ligands, including fluorinated phosphonic acids such as fluoroalkyl(ClO)phosphonic acid and pentafluorobenzylphosphonic acid, or hydrophobic fatty-chain ligands, or fluorinated ionic liquids. These ligands were chosen for their unique chemical properties, which increase the affinity of the adsorbent supports for PFAS.

[0039] The method adopted to functionalize the surface of the adsorbents involves grafting a metal oxide (MO X Preferably zirconium dioxide (ZrO2), in the form of nanoparticles or microparticles, is grafted with polyfluorinated and / or polyalkylated phosphonic ligands. This grafting process creates new adsorption sites, thereby increasing the selectivity and performance of the adsorbents.

[0040] The functionalization of these metal oxides with specific ligands improves the affinity of adsorbent materials for PFAS by multiplying the active sites and modifying the chemical surface of the material to promote interaction with these contaminants. This approach enables better capture and removal of PFAS in water treatment applications.

[0041] More specifically, the present invention relates to an adsorbent material comprising a support made of activated carbon or non-woven nanofibers, said support being impregnated with metal oxide nanoparticles, and said nanoparticles being functionalized by covalent bonding with polyfluoroalkyl and / or polyalkylated phosphonic ligands. This material is intended to adsorb per- and polyfluoroalkyl substances (PFAS) present in a liquid or gas, in order to purify said liquid or gas of these undesirable substances. For the purposes of this invention, "perfluoroalkyl and polyfluoroalkyl substances," also sometimes referred to as perfluorinated compounds, means synthetic organofluorinated substances.According to the OECD / UNEP (Organisation for Economic Co-operation and Development / United Nations Environment Programme) definition, PFAS are molecules formed from a chain of carbon atoms of varying lengths, linear, branched, or cyclic, and containing at least one saturated and fully fluorinated fluorinated group, either methyl or methylene. Various functional groups may be added to this fluorocarbon skeleton, giving these molecules distinct physical, chemical, and toxicological properties.

[0042] PFAS are toxic to humans and the environment. They are highly persistent pollutants that are widely present in water, air, soil, rain and ecosystems, as well as in human and animal organisms.

[0043] PFAS are distinguished according to their molecular mass.

[0044] Among the high molecular weight PFAS, that is to say with a molecular weight greater than 400 g / mol, the following PFAS can be cited: perfluorooctanoic acid (PFOA), perfluorononanoic acid (PFNA), perfluorohexanesulfonic acid (PFHxS), perfluorooundecanoic acid (PFUnA or PFUnDA), perfluorononanesulfonic acid (PFNS), perfluorooctanesulfonate (PFOS or SPFO), perfluorooctanesulfonamide (PFOSA), perfluorodecanoic acid (PFDA), perfluoroheptanesulfonic acid (PFHpS) and perfluorooundecanesulfonic acid (PFUnDS).

[0045] Examples of low molecular weight PFAS, i.e., with a molecular weight of less than 400 g / mol, include: heptafluorobutyric acid (HFBA or PFBA); perfluoroheptanoic acid (PFHpA); perfluoropentanoic acid (PFPeA); undecafluorohexanoic acid (PFHxA), perfluoro-n-heptanoic acid (PFHpA), perfluorobutane sulfonic acid (PFBS) and perfluoropentane sulfonic acid (PFPeS).

[0046] For the purposes of this invention, "support" means an adsorbent material serving as a support for other elements or functional groups that can be grafted onto said support by covalent bonds.

[0047] The choice of adsorbent support can vary depending on the desired configuration and application requirements, with options ranging from electrospun membranes or nanofibers to ceramic membranes, textile absorbents and different formats of activated carbon (granulated, extruded or powdered).

[0048] Granulated activated carbon (GAC) has established itself as a leading solution, but there is an ongoing need to improve its performance so that GAC is even more effective at removing PFAS compounds from the environment and drinking water. Ceramic membranes are also known to those skilled in the art as a preferred substrate for attaching functional elements and thus increasing the adsorption capacity of this adsorbent support.

[0049] A third support envisaged within the meaning of the invention consists of nonwoven nanofibers, that is to say, an array of nanofibers forming a surface and whose cohesion is ensured by physical and / or chemical methods, excluding weaving and knitting. Within this surface, the nanofibers can be oriented directionally (anisotropically) or randomly (isotropically); in the context of the present invention, they will preferably be oriented randomly. These nonwoven nanofibers are made of a polymeric material, composed of a single polymer or a mixture of several polymers.

[0050] These polymers are of synthetic or bio-based origin.

[0051] Examples of synthetic polymers include polyacrylic acid (PAA) and polyvinyl alcohol (PVA).

[0052] Among bio-based polymers, any polysaccharide polymer with hydroxyl or amine groups capable of interacting with ZrO2 can be used. Of these natural polymers, cellulose, chitosan, and mixtures thereof are preferred.

[0053] Preferably, these nanofibers are made up of a mixture of several polymers.

[0054] Preferably, these nanofibers are made up of a mixture of polyacrylic acid, polyvinyl alcohol and chitosan.

[0055] Nonwoven nanofibers are an advantageous substrate because their random structure offers high porosity, increased specific surface area, and a homogeneous fiber distribution, enabling better interaction with pollutants or target molecules. This configuration also promotes enhanced filtration and adsorption performance, while reducing the constraints associated with the complex manufacturing of woven materials.

[0056] According to another embodiment of the invention, the support consists of:

[0057] (i) either natural non-woven nanofibres, in particular made of natural polymers such as cellulose, chitosan or a mixture of both,

[0058] (ii) either natural non-woven nanofibres, in combination with synthetic fibers and / or minerals.

[0059] This support, which includes or is made of natural nanofibers, offers several advantages:

[0060] • excellent compatibility with functionalized ZrO2 nanoparticles;

[0061] • the presence of chemical functions allowing for better anchoring of the nanoparticles; and

[0062] • the biodegradability of the material as well as its low environmental impact. When the support is made of non-woven nanofibers composed of or comprising a natural polymer, the material according to the invention is more ecological, more compatible with natural environments, and has a very high active surface area.

[0063] For the purposes of this invention, "impregnated support" or "loaded support" refers to an adsorbent support as defined above, onto which chemical elements have been fixed. These will be, in particular, metallic nanoparticles.

[0064] For the purposes of this invention, "metallic nanoparticles" means particles of nanometric size, that is to say, having a diameter between 1 and 1000 nanometers, preferably between 1 and 100 nanometers, and more preferably between 1 and 10 nanometers, made up of one or more metallic oxides.

[0065] Metallic nanoparticles will be chosen from zirconium dioxide (ZrCh), zinc oxide (ZnO), titanium dioxide (TiCh), aluminium oxide (Al2O3), iron oxide (Fe2C>3, FesCU), cerium dioxide (CeCh), magnesium oxide (MgO) and manganese dioxide (MnCh).

[0066] According to a preferred embodiment of the invention, the metal oxide nanoparticles are zirconium dioxide (ZrCh) nanoparticles.

[0067] This nanometric or micrometric metal oxide serves as an interface between the ligand and the adsorbent support, facilitating grafting onto the latter.

[0068] Zirconium dioxide (ZrCh) is used not only for its ability to form strong bonds with phosphonic acid groups, but also for its remarkable stability under extreme pH conditions and even under irradiation.

[0069] According to one embodiment of the invention, the ZrC>2 nanoparticles are in the form of nanoparticles with an average size of 6 nm, dispersed in an aqueous suspension, preferably at 20% by weight. This concentration allows for a homogeneous distribution of the nanoparticles, ensuring their efficient integration within the adsorbent support.

[0070] By "functionalized nanoparticles" we mean, in the sense of the invention, nanoparticles on which functional chemical groups, also referred to as "ligands" because they have a binding affinity with ligand / receptor type PFAS, have been grafted by covalent bonding.

[0071] The ligands in question are polyfluorinated and / or polyalkylated phosphonic ligands, also referred to in this application as "polyfluorinated and / or polyalkylated groups," meaning they contain at least one chemical group comprising at least two fluorine (F) atoms and / or at least one alkyl group, with the general formula CnH2n+1, where n > 3. These ligands also contain a phosphonic acid functional group. The integration of a phosphonic acid functional group within the ligand structure ensures stable grafting to the surface of metal oxides. The phosphonic acid forms strong and stable bonds with zirconium dioxide (ZrCh). In this application, the terms "polyfluorinated and / or polyalkylated phosphonic ligands" and "polyfluorinated and / or polyalkylated ligands" are used interchangeably and refer to the same chemical groups.

[0072] Polyfluorinated ligands are chosen in particular from:

[0073] - fluoroalkyl phosphonic groups, in other words fluorinated phosphonic acid of general formula R-(CH2)nP(O)(OH)2, where R represents a polyfluoroalkyl chain, and n is an integer corresponding to the number of CH2 groups (preferably between 0 and 10);

[0074] - phosphonic fluoroaryl groups, in other words fluorinated phosphonic acid of general formula R-(CH2)nP(O)(OH)2, where R represents a polyfluorinated aromatic substituent, and n is an integer corresponding to the number of CH2 groups (n >0).

[0075] Polyalkylated groups are notably chosen from among the phosphonic groups with the general formula CnH2n+1-P(O)(OH)2, where CnH2n+1 corresponds to a linear or branched chain comprising at least 6 carbon atoms, such as the hexyl group (C6HI3), the dodecyl group (Cl2H 25), or other long-chain alkyls, used for their hydrophobicity and their ability to form organized structures on surfaces.

[0076] According to one embodiment of the invention, the nanoparticles are functionalized by covalent bonding with polyalkyl phosphonic, fluoroaryl phosphonic or fluoroalkyl phosphonic groups.

[0077] Preferably, the ligands of the adsorbent material of the invention are polyfluorophosphonic ligands, and more particularly are fluoroalkyl phosphonic groups.

[0078] Polyfluorinated ligands are notably chosen from fluoroalkyl (C10)phosphonic acid and pentafluorobenzylphosphonic acid.

[0079] According to a preferred implementation, the groups are fluoroalkyl phosphonic groups, which are in particular derived from fluoroalkyl phosphonic acid.

[0080] Preferably, the phosphonic polyfluorinated ligands are derived from (C10)phosphonic fluoroalkyl acid of CAS number 252237-39-1, which is commercially available, and notably distributed by the company SPECIFIC POLYMERS.

[0081] According to another preferred implementation, the groups are phosphonic fluoroaryl groups, which are in particular derived from pentafluorobenzylphosphonic acid.

[0082] Pentafluorobenzylphosphonic acid, CAS number 137174-84-6, is commercially available; it is notably distributed by companies such as TCI Chemicals or Sigma-Aldrich.

[0083] The adsorbent material is thus a composite material, consisting of at least three components: a support, metal oxide nanoparticles, and polyfluoro and / or polyalkylated phosphonic ligands / groups. In a preferred embodiment, the adsorbent material comprises, or consists of, activated carbon as a support, zirconium dioxide nanoparticles, and, as polyfluoro ligands, ligands derived from fluoroalkyl (C10)phosphonic acid.

[0084] According to another embodiment, the adsorbent material comprises, or consists of, non-woven nanofibers made of a mixture of polymers as a support, zirconium dioxide nanoparticles and, as polyfluorinated ligands, ligands derived from fluoroalkyl (C10)phosphonic acid.

[0085] According to another embodiment, the adsorbent material comprises, or consists of, non-woven nanofibers made of one or more natural polymer(s) as a support, zirconium dioxide nanoparticles and, as polyfluorinated ligands, ligands derived from pentafluorobenzylphosphonic acid.

[0086] Ligands are chemical entities of low weight compared to the total weight of the composite material (support + nanoparticles + ligands); the structural characterization of the adsorbent material presented below is therefore based on two relative quantities: that of the support and that of the functionalized metal oxide nanoparticles.

[0087] According to a preferred embodiment of the invention, the adsorbent material comprises between 90% and 99% by weight of adsorbent support made of activated carbon and between 1% and 10% by weight of functionalized metal oxide nanoparticles, relative to the total weight of the adsorbent material.

[0088] According to another preferred embodiment of the invention, the adsorbent material comprises between 60% and 99% by weight of adsorbent support made of non-woven nanofibers, and between 1% and 40% by weight of functionalized metal oxide nanoparticles, relative to the total weight of the adsorbent material.

[0089] Preferably, the adsorbent material of the invention is characterized in that the metal oxide nanoparticles represent between 1% and 5% by weight relative to the total weight of the adsorbent material, and more preferably represent 2% by weight relative to the total weight of the adsorbent material.

[0090] Processes for preparing the adsorbent material

[0091] The fixation conditions and the concentration of zirconium dioxide (ZrCh) in the activated carbon were carefully optimized to ensure homogeneous and stable integration of the nanoparticles within the activated carbon matrix.

[0092] This optimization relies on precise adjustments of several critical parameters, including pH, reaction time, and the mass / volume ratios of the metal oxide relative to the support. These parameters were adjusted to prevent any release of ZrC>2 nanoparticles during use, thus ensuring consistent and reliable performance of the adsorbent material while preserving the integrity of the activated carbon's active surface.According to a first embodiment, the process for preparing an adsorbent material according to the invention comprises the following steps: a) immersion of the support in a suspension comprising metal oxide nanoparticles in a solvent, preferably ethanol, to obtain a "loaded support"; b) drying of the loaded support in two sub-steps, first at a temperature between 100°C and 120°C, then at a temperature between 200°C and 240°C; c) immersion of the loaded and dried support in a suspension containing polyfluorinated and / or polyalkylated phosphonic ligands; d) drying of the "functionalized" support obtained in step (c), preferably at a temperature between 50 and 110°C; e) washing of the adsorbent material obtained with a suitable solvent, in particular with deionized water.

[0093] Preferably, step (b) of drying the loaded support lasts between 6 and 15 hours, preferably between 8 and 12 hours.

[0094] Preferably, step (d) of drying the functionalized support lasts between 4 and 12 hours, preferably between 6 and 10 hours.

[0095] According to a second embodiment, the process for preparing an adsorbent material according to the invention comprises the following steps: a) preparation of a suspension comprising metal oxide nanoparticles and polyfluorinated and / or polyalkylated phosphonic ligands in a solvent; b) optionally, vacuum drying at 40°C under rotation; c) immersion of a support in a suspension containing the metal oxide nanoparticles functionalized with polyfluorinated and / or polyalkylated ligands, then continuous homogenization by rotation; d) drying of the support obtained in step (c), preferably at a temperature between 50 and 110°C; e) washing of the adsorbent material obtained with a suitable solvent, in particular with deionized water.

[0096] The solvent used in step (a) will be chosen by the person skilled in the art based on the solubility of the ligand(s). In particular, it may be chosen from ethanol, water, or a mixture of the two.

[0097] The optional step (b) optimizes and accelerates the binding of the ligand(s) to the metal oxide nanoparticles. The polyfluorinated and / or polyalkylated ligands used inherently exhibit a high affinity for metal oxides, particularly ZrC>2. Therefore, the functionalization of the metal oxides can be carried out at room temperature. However, to ensure more homogeneous binding of the ligands, step (b) accelerates and homogenizes the binding of the ligand(s) to the metal oxide nanoparticles. Step (b) involves heating the mixture from step (a) to evaporate the solvent. This drying / heating step preferably lasts between 1 and 6 hours, and more preferably between 2 and 4 hours.

[0098] The functionalized metallic nanoparticles obtained at the end of steps (a) or (b) are then resuspended before step (c).

[0099] Steps (d) and (e) are identical to those presented previously.

[0100] In the case where the support is made of non-woven polymer nanofibers, a specific process for preparing the adsorbent material according to the invention is implemented.

[0101] The process for preparing an adsorbent material according to the invention from a non-woven nanofiber support comprises the following steps: a) preparation of a suspension comprising metal oxide nanoparticles and polyfluorinated and / or polyalkylated phosphonic ligands in a solvent; b) optionally, vacuum drying at 40°C under rotation; c) homogenization of the polymer in solution using a mixer, and addition of the metal oxide nanoparticles functionalized by said polyfluorinated and / or polyalkylated ligands; d) electrospinning of the polymer loaded with the functionalized nanoparticles obtained in step (c) to obtain nanofibers; e) drying of the nanofibers obtained in step (d), preferably at a temperature between 120 and 170°C, to obtain cross-linking of the polymer; f) washing of the adsorbent material obtained with a suitable solvent, in particular deionized water.

[0102] The solvent used in step (a) will be chosen by the person skilled in the art based on the solubility of the ligand(s). In particular, it may be chosen from ethanol, water, or a mixture of the two.

[0103] The optional step (b) optimizes and accelerates the binding of the ligand(s) to the metal oxide nanoparticles. The polyfluorinated and / or polyalkylated phosphonic ligands used inherently exhibit a high affinity for metal oxides, particularly ZrC>2. Therefore, the functionalization of the metal oxides can be carried out at room temperature. However, to ensure more homogeneous binding of the ligands, step (b) accelerates and homogenizes the binding of the ligand(s) to the metal oxide nanoparticles.

[0104] Step (b) consists of heating the suspension from step (a) to evaporate the solvent. This drying / heating step preferably lasts between 1 and 6 hours, and more preferably between 2 and 4 hours. The functionalized metal nanoparticles obtained from steps (a) or (b) are then added to the polymer in step (c), either as a dried powder or after resuspension.

[0105] Step (d) of electrospinning the polymer is carried out under the classic conditions, well known to those skilled in the art, to obtain nanofibers.

[0106] The polymer crosslinking is then obtained by drying in step (e), for a period of between 10 and 30 minutes.

[0107] According to a particular implementation, said polymer is made up, in part or in whole, of natural polymer(s), in particular chosen from cellulose, chitosan or one of their mixtures.

[0108] According to one embodiment, the natural nanofibers are dissolved or dispersed before the electrospinning step of the polymer (d).

[0109] According to another embodiment, the functionalized nanoparticles are integrated directly into natural nanofibers that have been previously molded, carded or extruded.

[0110] Preferably, and as shown in the examples, the processes described above are carried out using a specific molar ratio (ligands:metal oxide).

[0111] Thus, according to a preferred embodiment of the invention, the process for preparing the adsorbent material is characterized in that the molar ratio of ligands to metal oxide used is between 1:20 and 1:80, said molar ratio being preferably 1:50.

[0112] Process for capturing perfluoroalkyl and polyfluoroalkyl substances (PF AS)

[0113] The present invention also relates to a method for capturing per- and poly-fluoroalkyl substances (PFAS) comprising bringing a liquid or gas capable of containing PFAS into contact with the adsorbent material according to the invention, or as obtained by one of the methods according to the invention.

[0114] Capture or adsorption, in the sense of the invention, means the attachment of PFAS to the material according to the invention, by physico-chemical interactions of the type of non-covalent bonds; said non-covalent bonds being nevertheless sufficiently strong to resist the flow of the liquid or gas.

[0115] The uptake rate (or adsorption capacity) is assessed using "breakthrough rate" or "percentage breakup" measurements. For these measurements, a bed of adsorbent material is pressurized and purged with a gas or liquid. Once the system reaches equilibrium, substances to be adsorbed (called "adsorbates") are added to the inlet liquid or gas. The change in concentration of these substances in the effluent at the outlet of the fixed-bed adsorber is monitored as a function of the effluent volume.

[0116] A satisfactory capture rate is considered to correspond to a breakthrough percentage at the system outlet of less than 10%. According to one embodiment of the process of the invention, the PFAS captured by the material of the invention are low molecular weight, high molecular weight, or a mixture of both. For the purposes of the invention, "high molecular weight PFAS" means PFAS with a molecular weight greater than 400 g / mol, for example, the following PFAS: PFOA, PFNA, PFHxS, PFUnDA, and PFNS.

[0117] For the purposes of this invention, "low molecular weight PFAS" means PFAS with a molecular weight of less than 400 g / mol. Examples of PFAS belonging to this category include: PFBA, PFPeA, PFHxA, PFHpA, PFBS, and PFPeS.

[0118] Advantageously, the process of the invention is adapted to capture low molecular weight PFAS.

[0119] Finally, this application relates to the use of the adsorbent material as defined above, or as obtained by one of the processes defined above, to capture per- and poly-fluoroalkyl substances (PFAS) present in a liquid or a gas.

[0120] Liquids likely to contain PFAS include water polluted and / or contaminated by PFAS, particularly polluted and / or contaminated groundwater and surface water located near industrial sites, landfills, or fire training areas where fluorinated firefighting foams have been used. Drinking water may also contain PFAS, especially if it comes from contaminated sources or if the treatment processes used do not allow for their effective removal. Furthermore, domestic and industrial wastewater represent a major source of contamination, particularly wastewater from manufacturing activities such as the production of waterproof textiles, non-stick coatings, or fluorinated foams.Leachate from landfills and industrial effluents containing PFAS, generated during processes such as electroplating or semiconductor manufacturing, are also contaminated liquids. Finally, some commercial or household liquids, such as cleaning products, waterproofing sprays, and specialized chemical solutions, may contain PFAS, thus increasing their dispersion in the aquatic environment.

[0121] Among the gases likely to contain PFAS, industrial emissions are the primary source, particularly those from the manufacturing processes of fluorinated materials such as non-stick coatings, waterproof textiles, and fire-fighting foams. Gases emitted by the incomplete incineration of PFAS-containing waste, such as food packaging or used chemicals, can also release these compounds as vapors or volatile particles. Emissions from wastewater treatment plants, especially vapors from contaminated sludge, represent another significant source of airborne contamination. Furthermore, some fluorinated gases used as refrigerants, solvents, or propellants may contain PFAS or their precursors. Aerosols containing fluorinated substances, such as stain-resistant or water-repellent sprays, also contribute to the dispersion of PFAS in the air.Finally, accidental emissions, for example during the storage or transport of fluorinated chemicals, as well as gases produced by the thermal degradation of fluorinated materials, constitute potential sources to monitor in order to limit the spread of these persistent contaminants in the atmosphere.

[0122] Geotextile comprising the material of the invention

[0123] The adsorbent material according to the invention can advantageously be integrated into a technical geotextile, thus forming a barrier device for the preventive protection of soils, groundwater and aquifers.

[0124] According to one of its aspects, the present invention relates to a geotextile comprising the adsorbent material according to the invention, said material being incorporated into a textile matrix.

[0125] For the purposes of this invention, "geotextile" refers to a textile material in the form of a flexible, permeable, and resistant sheet, used in civil engineering, construction, and landscaping. This material primarily serves to filter, separate, drain, protect, or reinforce soils. It allows water to pass through while preventing the migration of fine particles, making it essential for soil stabilization and preventing contamination. Geotextiles are available in woven and non-woven versions and are most often made of synthetic fibers.

[0126] The geotextile according to the invention can advantageously be used to intercept perfluoroalkyl and polyfluoroalkyl substances (PFAS) present in infiltrating waters, before they reach the aquifer, thus enabling non-intrusive in situ remediation.

[0127] According to one embodiment, the adsorbent material is incorporated into a non-woven or woven textile matrix, in the form of:

[0128] • of a functionalized particulate adsorbent material (1-500 g / m²) 2 ),

[0129] • said material being dispersed in the textile matrix according to processes of integration of granular fillers in geotextile products.

[0130] The integration of the adsorbent material within the geotextile can be carried out according to:

[0131] • one deposit per bed,

[0132] • a mechanical insertion into the fiber during the production of the textile matrix,

[0133] • incorporation in the form of thermally sealed reactive pouches,

[0134] • Or a combination of mechanical insertion and heat sealing.

[0135] The geotextile thus produced is intended to capture perfluoroalkyl and polyfluoroalkyl substances (PFAS) transported by infiltrating waters.

[0136] In a preferred embodiment, the material incorporated into the textile matrix comprises polyfluoro ligands derived from pentafluorobenzylphosphonic acid. Such ligands exhibit a very high affinity for both high and low molecular weight PFAS. The optimal load of functionalized material can vary between 5 and 500 g / m². 2 depending on the pollution scenarios, ensuring an effectiveness period ranging from 10 years to over 100 years depending on the mass fluxes of PFAS observed in the infiltration waters.

[0137] The present invention also relates to the use of the geotextile as described above, as a barrier to prevent the migration of perfluoroalkyl and polyfluoroalkyl substances (PFAS) into soils, groundwater, and / or aquifers. Such a geotextile according to the invention constitutes a robust, passive, durable, and economical solution for:

[0138] • the protection of sensitive areas,

[0139] • the decontamination of contaminated industrial sites,

[0140] • the protection of stormwater management facilities,

[0141] • the protection of fire training areas, and

[0142] • the protection of landfill leaching zones.

[0143] EXAMPLES

[0144] The effectiveness of the adsorbent materials according to the invention is demonstrated in the examples below. A significant increase in the adsorption capacity of PFAS is observed after the functionalization of the adsorbent support, via the attachment of functionalized metal oxide nanoparticles.

[0145] In these examples, the chosen medium is granular activated carbon, with a specific surface area of ​​approximately 1100 m². 2 / g, obtained from the manufacturer BIJIN. The metal oxide nanoparticles are made of Zirconium dioxide (ZrU2).

[0146] Example 1. Fixation of zirconium dioxide onto activated carbon

[0147] The fixation conditions and the concentration of zirconium dioxide (ZrC>2) in the activated carbon were carefully optimized to ensure homogeneous and stable integration of the nanoparticles within the activated carbon matrix.

[0148] This optimization relies on precise adjustments of several critical parameters, including pH, reaction time, and the mass / volume ratios of the metal oxide relative to the support. These parameters were adjusted to prevent any release of ZrC>2 nanoparticles during use, thus ensuring consistent and reliable performance of the adsorbent material while preserving the integrity of the activated carbon's active surface. The ZrC>2 content was quantified using thermogravimetric analysis (TGA), allowing for the measurement of the proportion of incorporated ZrC>2.

[0149] The results presented in Figure 1 reveal a residual content of 2.6 wt%, very close to the theoretical target value of 2%. This proximity between the measured and theoretical values ​​confirms the efficient and controlled fixation of zirconium dioxide in the activated carbon, thus demonstrating the reliability of the optimized fixation conditions. Furthermore, the textural analysis of the modified activated carbon (Figure 2) indicates a slight reduction in specific surface area after the incorporation of ZrC>2. This decrease testifies to the successful fixation of the nanoparticles in the matrix, without compromising the overall adsorption capacity of the activated carbon at a content of 2 wt%. Indeed, despite this slight decrease in active surface area, the material retains a substantial number of adsorption sites available for water treatment applications, thus ensuring that the modified ZrC>2 continues to meet the performance requirements for PFAS removal.

[0150] When the ZrC>2 content is maintained at 2 wt%, nanoparticle fixation is optimally achieved under moderately acidic pH conditions, around 6, and at room temperature. These conditions promote a stable interaction between the ZrC>2 nanoparticles and the activated carbon surface, contributing to a homogeneous and stable particle distribution within the matrix and ensuring increased efficiency in water treatment applications.

[0151] Example 2. Process for functionalizing metal oxide nanoparticles

[0152] The functionalization was carried out while maintaining a ligand / ZrCh molar ratio of 1 / 50, optimized to maximize surface coverage without excessive saturation.

[0153] The functionalization process began with step (a): dissolving the ligand in absolute ethanol, followed by the gradual, drop-by-drop addition of this solution to the aqueous suspension of ZrC>2. This controlled process ensures homogeneous dispersion of the ligand around the suspended nanoparticles. Once the addition was complete, the mixture was subjected to constant agitation for 6 hours, ensuring complete interaction between the ligand and the surface of the ZrC>2 nanoparticles.

[0154] In the next step (b), the ethanol was removed by vacuum evaporation at 40°C using a rotary evaporator, resulting in a dry powder of functionalized nanoparticles, ready for incorporation into adsorbent supports.

[0155] It is important to note that this functionalization was initially performed on suspended ZrC>2 nanoparticles. However, this process can also be applied to ZrC>2 nanoparticles after their incorporation into the adsorbent support.

[0156] Example 3. PFOA Adsorption Test

[0157] To evaluate the adsorption performance of functionalized zirconium dioxide (functionalized ZrC>2) compared to that of virgin activated carbon, two adsorption experiments were conducted using the same perfluorooctanoic acid (PFOA) solution at a concentration of 54 mg L⁻¹ -1 (ppm). For each test, the adsorbent concentration was set at 1 g-L. 1 , whether for functionalized ZrC>2 or virgin activated carbon, in order to maintain comparable experimental conditions.

[0158] The mixtures were agitated for 4 hours, allowing sufficient contact time for adsorption equilibrium to be established between the adsorbent and the suspended PFOA. Subsequently, each mixture was centrifuged to efficiently separate the adsorbent from the liquid phase. The resulting supernatant was carefully collected and analyzed to determine the residual PFOA concentration.

[0159] Analyses of the PFOA solution before and after adsorption were carried out by gas chromatography coupled to tandem mass spectrometry (GC-MS-MS), a highly sensitive and specific detection method, allowing precise measurement of the reduction in PFOA concentration in each case.

[0160] The results, presented in Figure 3, show a higher adsorption efficiency for functionalized ZrU2 compared to virgin activated carbon. The adsorption efficiency of unfunctionalized ZrC>2 nanoparticles is zero and is therefore not shown in Figure 3.

[0161] These results suggest that functionalizing ZrC>2 significantly improves its affinity for PFOA, likely due to specific interactions between the ligand's fluorinated groups and the perfluorinated chains of PFOA. This observation supports the potential of functionalized ZrC>2 as an advanced adsorbent material for treating perfluorinated contaminants in water.

[0162] Example 4. Study of adsorption isotherms

[0163] The study of adsorption isotherms is crucial for understanding the performance of an adsorbent material in contaminant treatment. Isotherms allow us to analyze the relationship between the amount of solute adsorbed by the adsorbent and the concentration of the solute remaining in solution at a constant temperature. These experimental curves provide essential information on the adsorption capacity, interaction mechanisms, and surface characteristics of the adsorbent.

[0164] Among the isotherms frequently used in adsorption chemistry, the Langmuir isotherm is one of the most common, particularly because of its relevance to homogeneous adsorbent surfaces.

[0165] The Langmuir isotherm relies on several simplifying assumptions. It assumes that adsorption is a unimolecular process, meaning that each solute molecule is adsorbed onto a single active site. This model also assumes that: the adsorbent surface is homogeneous, with energetically equivalent adsorption sites; once a site is occupied by a molecule, no other adsorbate can bind to it; and adsorption and desorption are in dynamic equilibrium.

[0166] The equation for the Langmuir isotherm is written as follows: where: oq e is the amount of adsorbate adsorbed per unit mass of adsorbent at equilibrium (mg / g), o Qmax represents the maximum adsorption capacity (mg / g), o KL is the Langmuir constant (L / mg), which reflects the affinity of the adsorbent for the adsorbate, o Ce is the concentration of the adsorbate in solution at equilibrium (mg / L).

[0167] The Langmuir isotherm allows for a precise measurement of the adsorption capacity of a material for a given solute.

[0168] By fixing the concentration of the solute, it is possible to determine the maximum amount that the adsorbent can adsorb before saturation, thus providing critical information for industrial applications where adsorption performance is essential.

[0169] The Langmuir model is particularly useful for homogeneous adsorbents and applications where monolayer is possible.

[0170] The Langmuir isotherm is a fundamental tool for characterizing the performance of adsorbents, particularly for materials with a homogeneous surface where unimolecular adsorption is observed. By providing detailed information on the adsorption capacity and affinity of the material for the solute, the Langmuir isotherm helps optimize the selection and conditions of use of adsorbents, thus contributing to the efficiency of treatment processes in diverse fields such as water and industrial effluent treatment.

[0171] Batch adsorption tests were conducted to evaluate the PFOA capture performance of functionalized zirconium dioxide (ZrCh) under standardized test conditions to ensure reproducibility of results.

[0172] The experiments were carried out at a stirring speed of 300 revolutions per minute (rpm) for 30 minutes, ensuring homogeneous contact between the adsorbent and the PFOA solution.

[0173] The concentration of the adsorbent was set at 1 gL. 1 , while the initial PFOA concentrations were 54, 140, and 300 mg-L 1 , simulating different pollution conditions to evaluate adsorption efficiency as a function of concentration: see figure 4(1). The results obtained made it possible to model adsorption according to the Langmuir model, showing that adsorption initially takes place in a homogeneous manner, with a high affinity between functionalized ZrU2 and PFOA molecules, until the formation of a complete monolayer corresponding to a 100% coverage.

[0174] Beyond this saturation of the monolayer, a multilayer adsorption begins to form, allowing the material to continue to adsorb PFOA molecules, although the efficiency gradually decreases due to the crowding of active sites.

[0175] As illustrated in Figure 4(1), experimental data show an adsorption efficiency of PFOA of over 95% for an initial concentration less than or equal to 54 mg L -1 , which highlights the high affinity of functionalized ZrC>2 for PFOA under low contamination conditions.

[0176] Figure 4(2) illustrates the evolution of the recovery rate (%) as a function of the initial concentration (Co) of PFOA, expressed in ppm (mg.L -1The results reveal a progressive and marked increase in the coverage rate with increasing initial concentration, suggesting a positive correlation between Co and the efficiency of the adsorption process. At an initial concentration of 54 ppm, the coverage rate is relatively low, reaching only 40%. Despite this moderate value, the result indirectly indicates a high adsorption capacity, suggesting that only a fraction of the available surface area is initially utilized. At Co = 140 ppm, the coverage rate rises to 89%, reflecting near-saturation of the adsorbent surface, likely due to the almost complete occupation of available adsorption sites. Finally, at Co = 300 ppm, the coverage rate reaches 147%, thus exceeding 100%.This result indicates the formation of a multilayer of adsorbates, confirming that, following the saturation of the sites in the first monolayer, interactions between adsorbed molecules promote the deposition of additional layers. This trend highlights amplified adsorption phenomena, potentially associated with intermolecular interactions.

[0177] Figure 5 illustrates the adsorption isotherm of PFOA on functionalized ZrC>2, compared to the theoretical Langmuir model. The x-axis (C e in mrnol.L" 1 ) represents the equilibrium concentration of the compound in solution, while the ordinate axis (Q e en mrnol.g" 1 ) indicates the amount adsorbed per unit mass of the adsorbent. Experimental data (represented by the gray curve) show a rapid increase in Q e at low concentrations of C e, suggesting a strong initial affinity between the adsorbent and the adsorbate. However, at high concentrations, the curve tends to stabilize, indicating a progressive saturation of the available adsorption sites on ZrC>2.

[0178] In comparison, the Langmuir model (black dotted curve) reproduces the experimental data well at low concentrations, but diverges at high C values e This divergence could reflect the presence of additional adsorption mechanisms, such as multilayer adsorption or intermolecular interactions not taken into account in the Langmuir model, which assumes monolayer adsorption on a homogeneous surface.

[0179] The maximum adsorption capacity, reaching 129 mg of PFOA per gram of functionalized ZrC>2, confirms the high performance of this material, with monolayer saturation at this maximum capacity.

[0180] Based on these results, it is estimated that one gram of functionalized zirconium dioxide can retain approximately 2.10 20 PFOA molecules. This is significantly higher than what is estimated for one gram of activated charcoal, which retains approximately 6.10 18 PFOA molecules.

[0181] These observations demonstrate the robustness of the adsorption capacity of functionalized ZrC>2, not only in low to medium contamination conditions, but also in highly contaminated environments where multilayer formation becomes possible.

[0182] Example 5. Selectivity of PFAS adsorption by the material according to the invention

[0183] Figure 6 illustrates the adsorption selectivity of virgin activated carbon towards 14 different PFAS. It is clear that only PFAS with long chains (11 carbons) have a breakthrough rate of less than 10% after washing the adsorbent material.

[0184] To evaluate the selectivity of zirconium dioxide (ZrCh) after its functionalization, a comparative study was carried out with virgin activated carbon as a control.

[0185] A mixture of PFAS was prepared containing:

[0186] - Perfluoropentanoic acid (PFPa) as a model of low molecular weight (5 carbons) PFAS,

[0187] - perfluorooctanoic acid (PFOA) as a model high molecular weight molecule (8 carbons), and

[0188] - bisphenol A as a model of an organic pollutant.

[0189] The initial concentrations of these compounds in the mixture were respectively 1600 ppb for PFPeA, 1020 ppb for PFOA, and 540 ppb for bisphenol A.

[0190] For each experiment, the concentration of the adsorbent was standardized to 1 g-L. 1, both for functionalized ZrÛ2 and for virgin activated carbon, thus guaranteeing comparable experimental conditions.

[0191] The mixtures were stirred for 4 hours, providing sufficient contact time for adsorption equilibrium to be established. Following this phase, each mixture was centrifuged to efficiently separate the adsorbent from the liquid phase. The supernatant was carefully collected and analyzed to determine the residual concentrations of the adsorbed compounds.

[0192] The analyses were carried out using gas chromatography coupled with tandem mass spectrometry (GC-MS-MS), a detection method renowned for its high sensitivity and specificity, allowing for the precise measurement of the reduction in the concentration of the various pollutants after adsorption.

[0193] The results, presented in Figure 7, indicate a significantly higher adsorption efficiency for functionalized ZrÛ2 compared to virgin activated carbon, regardless of the PFAS.

[0194] Advantageously, low molecular weight PFPeA is adsorbed much better by functionalized ZrC>2 than by activated carbon.

[0195] LIST OF BIBLIOGRAPHICAL REFERENCES

[0196] Stebel, EK, Pike, KA, Nguyen, H., Hartmann, HA, Klonowski, MJ, Lawrence, MG, ... & Edmiston, PL (2019). Absorption of short-chain to long-chain perfluoroalkyl substances using swellable organically modified silica. Environmental Science: Water Research & Technology, 5(11), 1854-1866.

[0197] Gagliano, E., Sgroi, M., Falciglia, P. P., Vagliasindi, F. G., & Roccaro, P. (2020). Removal of poly- and perfluoroalkyl substances (PFAS) from water by adsorption: Role of PFAS chain length, effect of organic matter and challenges in adsorbent regeneration. Water research, 171, 115381.

[0198] WO 2020 / 206317

[0199] WO 2022 / 109392

[0200] WO 2023 / 107629

Claims

23 DEMANDS 1. Adsorbent material comprising a support made of activated carbon or non-woven nanofibres, said support being impregnated with metal oxide nanoparticles, and said nanoparticles being functionalized by covalent bonding with polyfluorinated and / or polyalkylated phosphonic ligands.

2. Adsorbent material according to claim 1, characterized in that the metal oxide nanoparticles are zirconium dioxide (ZrU2) nanoparticles.

3. Adsorbent material according to any one of claims 1 or 2, characterized in that the nanoparticles are functionalized by covalent bonding with phosphonic polyalkyl, phosphonic fluoroalkyl or phosphonic fluoroaryl groups.

4. Adsorbent material according to claim 3, characterized in that the fluoroalkyl phosphonic groups are derived from fluoroalkyl phosphonic acid.

5. Adsorbent material according to claim 3, characterized in that the phosphonic fluoroaryl groups are derived from pentafluorobenzylphosphonic acid.

6. Adsorbent material according to any one of claims 1 to 5, characterized in that the support is made of: (i) natural non-woven nanofibers, in particular made of polymers such as cellulose, chitosan or a mixture of both, or (ii) natural non-woven nanofibers in combination with synthetic fibers and / or minerals.

7. Adsorbent material according to any one of claims 1 to 6, characterized in that the metal oxide nanoparticles represent between 1% and 5% by weight relative to the total weight of the adsorbent material, and preferably represent 2% by weight relative to the total weight of the adsorbent material.

8. A process for preparing an adsorbent material according to any one of claims 1 to 7, comprising the following steps: a) immersing the support in a suspension comprising metal oxide nanoparticles in a solvent, preferably ethanol, to obtain a charged support; b) drying the charged support in two sub-steps, first at a temperature between 100°C and 120°C, then at a temperature between 200°C and 240°C; c) immersing the charged and dried support in a suspension containing polyfluorinated and / or polyalkylated phosphonic ligands; d) drying of the functionalized support obtained in step (c), preferably at a temperature between 50 and 110°C; e) washing of the adsorbent material obtained with a suitable solvent, in particular with deionized water.

9. A method for preparing an adsorbent material according to any one of claims 1 to 7 comprising the following steps: a) preparing a suspension comprising metal oxide nanoparticles and polyfluorinated and / or polyalkylated phosphonic ligands in a solvent; b) optionally, drying under vacuum at 40°C under rotation for evaporation of said solvent; c) immersing a support in a suspension containing the metal oxide nanoparticles functionalized with said ligands, then continuous homogenization by rotation; d) drying the loaded support obtained in step (c), preferably at a temperature between 50 and 110°C; e) washing the adsorbent material obtained with a suitable solvent, in particular with deionized water.

10. A method for preparing an adsorbent material according to any one of claims 1 to 7, characterized in that the support consists of non-woven polymer nanofibers, comprising the following steps: a) preparation of a suspension comprising metal oxide nanoparticles and polyfluorinated and / or polyalkylated phosphonic ligands in a solvent; b) optionally, vacuum drying at 40°C under rotation for evaporation of said solvent; c) homogenization of the polymer in solution using a mixer, and addition of the metal oxide nanoparticles functionalized with polyfluorinated and / or polyalkylated ligands; d) electrospinning of the polymer loaded with the functionalized nanoparticles obtained in step (c) to obtain nanofibers; e) drying of the nanofibers obtained in step (d), preferably at a temperature between 120 and 170°C; f) washing the adsorbent material obtained with a suitable solvent, in particular deionized water.

11. A method for preparing an adsorbent material according to claim 10, characterized in that said polymer is made up partially or completely of a natural polymer, in particular selected from cellulose, chitosan and mixtures thereof.

12. A preparation process according to any one of claims 8 to 11, characterized in that the molar ratio ligands: metal oxide used is between 1:20 and 1:80, said molar ratio preferably being 1:

50.

13. A method for capturing perfluoroalkyl and polyfluoroalkyl substances (PFAS) comprising bringing a liquid or gas capable of containing PFAS into contact with the adsorbent material according to any one of claims 1 to 7.

14. A method for capturing perfluoroalkylated and polyfluoroalkylated substances (PFAS) according to claim 13, characterized in that the PFAS are of low or high molecular weight, and are in particular selected from perfluorooctanoic acid (PFOA) and perfluoropentanoic acid (PFPEA).

15. Use of the adsorbent material according to any one of claims 1 to 7, for capturing perfluoroalkyl and polyfluoroalkyl substances (PFAS) present in a liquid or gas.

16. Geotextile comprising the adsorbent material according to any one of claims 1 to 7, said material being incorporated into a textile matrix.

17. Use of the geotextile according to claim 16, as a barrier to prevent the migration of perfluoroalkyl and polyfluoroalkyl substances (PFAS) into soils, groundwater and / or aquifers.

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