FR3047992A1 - COMPOSITE MATERIAL FOR PASSIVE SAMPLER AND USE THEREOF. - Google Patents

Abstract

Composite material for the sorption of both hydrophobic and hydrophilic molecules, characterized in that it comprises a silicone-based elastomer matrix capable of absorbing and / or adsorbing ions or molecules with a hydrophobic nature, in which is dispersed at least a polymeric material in the form of solid particles capable of absorbing and / or adsorbing ions or molecules of a hydrophilic nature. A passive sampler comprising such a composite material can be used for the sorption of both hydrophilic ions and molecules and hydrophobic ions or molecules in a liquid medium, aqueous and / or organic, in gaseous (atmospheric) medium, in sediments in biological media or in food matrices.

Description

FIELD OF THE INVENTION

The present invention relates to the field of passive sampling, and more particularly relates to a material for performing extraction or sampling of molecules, as well as the method of producing such a material and its use.

STATE OF THE PRIOR ART

For the analysis and control of micropollutants (molecules), such as pesticides, in the environment, particularly in surface water or groundwater, so-called passive sampled devices have been developed. These devices are installed in the medium to be studied (by immersion) and left in place for several days or weeks, during which time they accumulate the ions or target molecules, by absorption and / or adsorption. This technique makes it possible to pre-concentrate the molecules in the medium to be studied, then to analyze in the laboratory a multiplicity of molecules present in the trace state in the environment.

This passive sampling technique is based on the mechanisms of diffusion of the molecules of the aquatic medium towards the receiving phase of the device. This receiving phase can be a liquid as in the semi-permeable membrane devices (SPMDs), or a microporous adsorbent material in devices called POCIS (Polar Organic Compounds Integrative Samplers: sampled for polar organic molecules), or an absorbent polymer (LDPE membranes: Low Density PolyEthylene, low density polyethylene, or PDMS: PolyDiMethylSiloxane) The receiving phase must have mechanical properties to withstand exposure in a medium subject to high current velocities and presence of debris, without being dispersed or degraded. Some devices, such as POCIS or SPMD, include a membrane to protect the receptor phase.

SBSE (Stir Bar Sorptive Extraction) is an extraction technique used in the laboratory that is based on the sorption of dissolved molecules, most often in aqueous phase, by a magnetic bar covered with a polymer (in particular the PDMS). From this technique of extraction of molecules in a water sample, a passive sampling technique was developed (Passive SBSE) based on the direct immersion of SBSE bars in the medium to be analyzed. The moderately hydrophobic to hydrophobic molecules, which have more affinity for PDMS than for water, then concentrate on the SBSE bar.

However, only two categories of receptor phases are currently available: the receptor phases (for example POCIS) retaining the hydrophilic molecules (0 <logKow <3), and - the receptor phases (PDMS / SBSE, LDPE) or SPMD) retaining hydrophobic molecules (3 <logKow <10).

For example, POCIS concentrates hydrophilic pesticides that have a higher affinity for water, while SBSE concentrates rather hydrophobic pesticides. The analysis of the different types of passive samplers previously exposed in the medium is then carried out in the laboratory. The extraction of the molecules retained on the passive samplings is carried out, either by chemical desorption (for the POCIS or the SBSE), or by thermal desorption (SBSE), for their analysis generally by gas chromatography or high performance liquid chromatography. .

The results obtained, that is to say the ions or molecules detected and analyzed, therefore depend mainly on the passive sampler used and the nature of the material (s) component (s) the receiving phase. Indeed, currently, to extract a large number of molecules having a range of extended polarity, it is necessary to perform pre-concentration steps with several receiver phases of different polarities. This pre-concentration capacity makes it possible to improve the quantification limits for the targeted molecules and to eliminate analytical interferences.

A first aim of the present invention is therefore to propose a single receiver phase, for passive sampling, which makes it possible to widen the range of polarity of the molecules retained, in a single pre-concentration operation.

Since these passive samplings are intended to be placed in the natural environment (stream, for example), another object of the invention is to provide a receiving phase that is made of a material sufficiently strong to be suitable for such use.

Another object of the invention is to provide a receiver phase for passive sampling that is more economical than devices currently in commerce.

DESCRIPTION OF THE INVENTION For this purpose, the inventors have developed a composite material for the sorption of both hydrophobic and hydrophilic molecules, characterized in that it comprises a silicone-based elastomer matrix capable of absorbing and / or adsorbing hydrophobic ion or molecule in which at least one polymeric material is dispersed in the form of solid particles capable of absorbing and / or adsorbing hydrophilic ions or molecules.

This material is advantageously in the form of plates which can then be subdivided into parallelepipedal rods to be introduced directly into the medium to be sampled. The silicone elastomer matrix is flexible and resistant. Preferably it is formed mainly of a polysiloxane, preferably a polyalkylsiloxane, such as polydimethylsiloxane (PDMS) or a polymethylsiloxane comprising vinyl and / or phenyl and / or fluorinated groups.

Polydimethylsiloxane, commonly known as PDMS, is a hydrophobic organo-mineral polymer of the siloxane family.

This polymer has good mechanical strength, stability in water, tolerance for a wide range of organic solvents (possibly swelling of the polymer but no degradation) and resistance to high temperature. This thermal resistant allows direct thermal desorption of molecules accumulated up to about 300 ° C. It also has a unique flexibility resulting from a low glass transition temperature (Tg = -123 ° C). In addition, this flexibility, coupled with an amorphous structure, allows the diffusion of small molecules in this material. Other polymers may be used to form said elastomer matrix: they belong for example to the following families (according to the standard silicone initials, Technical File No. 2880, 2007); elastomers or silicone rubber comprising the following groups: MQ: only methyl groups such as dimethylpolysiloxane, PMQ: methyl and phenyl groups, PVMQ: methyl, phenyl and vinyl groups, VMQ: methyl and vinyl groups, FMQ: methyl and fluorinated groups, FVMQ: methyl, vinyl and fluorinated groups.

Advantageously, the solid particles of polymeric material, dispersed in said elastomeric matrix, have a particle size less than or equal to 100 micrometers, preferably less than or equal to 60 micrometers, more preferably less than or equal to 30 micrometers. This particle size is preferably greater than or equal to 2 μm.

Indeed the more the particles are fine, the more the incorporation into the matrix is facilitated, and the more the elasticity of the matrix is retained.

Preferably, the polymeric material forming the solid particles is chosen from: a divinylbenzene and / or N-vinylpyrrolidone polymer, a styrene-divinylbenzene copolymer including hydroxyl, vinylpyridine, vinylimidazole, cyanomethylstyrene, amide groups, a divinylbenzene-N copolymer -vinylpyrrolidone including or not quaternary amine groups, a poly (meth) acrylate, alone or in a mixture.

According to an advantageous embodiment, said polymeric material forming the solid particles is a polymer which has both hydrophobic and hydrophilic properties, such as a divinylbenzene-N-vinylpyrrolidone copolymer. Indeed, this copolymer has both an N-vinylpyrrolidone subunit which has a hydrogen binding acceptor site for participating in the sorption of hydrophilic chemicals and a divinylbenzene subunit which can form specific interactions with hydrophobic molecules. thanks to its aromatic groups. The inventors have found, surprisingly, that such a polymeric material containing at least 50 mol% of hydrophobic monomers has the advantage of better incorporation of the particles into the silicone-based elastomer matrix, and results in better cohesion of the constituents. composite material, thereby participating in the resistance of the composite material in the natural environment, for use as a passive sampler in such a medium (watercourse for example).

The solid particles of polymeric material may be present in said silicone matrix in mass proportions of between 1% and 50%, preferably between 2 and 30%, more preferably between 5 and 15%, of the total mass. of the silicone matrix with the solid particles.

In these proportions, the physical and chemical properties of the silicone matrix are generally conserved.

A mass proportion of 5 to 15% is particularly advantageous for particles having a particle size of between approximately 30 μm and 60 μm.

Said solid particles of polymeric material are advantageously dispersed within the silicone-based matrix in at least one zone close to the periphery (ie incorporated in at least one zone close to the external surface, and not exclusively on the surface) of said matrix.

When said matrix is of small thickness (for example in the form of a plate or rod approximately 0.5 to 3 mm thick), said solid particles made of polymeric material are preferably distributed homogeneously throughout said matrix . But preferably the matrix is not in the form of a film or a membrane (whose thickness is generally around a few tens of micrometers), which matrix is too fragile and not able to hold said solid particles in place.

The present invention also relates to a passive sample for the sorption of both ions and hydrophilic molecules and hydrophobic ions or molecules by means of a receiving phase, characterized in that the receiving phase comprises the composite material such as described above. Such a receiving phase can be exposed directly in the natural environment with any means of attachment (drilling or clamping of the composite material) or it can be integrated in a device comprising support elements of the receiving phase.

According to an advantageous embodiment, the receiving phase of the passive sampler consists essentially of said composite material according to the invention.

The present invention also relates to the use of the composite material as described above for the sorption of both hydrophilic ions or molecules and hydrophobic ions or molecules in a liquid medium, aqueous and / or organic, in a medium gaseous (eg atmospheric), in sediments, in biological media or in food matrices.

This use of the composite material may be aimed at absorbing and / or adsorbing at the same time ions or molecules having an octanol / water partition coefficient log Kow of between 0.0 and 10.0, preferably between 0.6 and 5, 5. Thus during the same exposure in the medium to be studied, it is possible to retain on said composite material a multiplicity of ions or molecules in a wide range of polarity.

Said molecules may especially be herbicides, fungicides, insecticides, organophosphorus compounds, aromatic hydrocarbons, such as polycyclic aromatic hydrocarbons (PAHs), organo-halogenated compounds such as polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs). ), polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), perfluorinated compounds (PFCs), detergents such as alkylphenols, surfactants, plasticizers such as phthalate esters and / or bisphenols, pharmaceuticals such as beta-blockers, antidepressants, lipid-lowering drugs, analgesics, antibiotics, bronchodilators, chemotherapy products, hormones, cosmetics, or a mixture of several of these.

The composite material according to the invention may also be used for the preconcentration of ions or hydrophilic and / or hydrophobic molecules in the form of traces (from a few ng / L to mg / L), for example in a natural medium or for an application in an analysis laboratory.

Alternatively, the composite material according to the invention can also be used to depollute an environment containing hydrophilic and / or hydrophobic ions or molecules.

The present invention also relates to the method of manufacturing the composite material as described above, the method comprising the following successive steps: i) - mixture of siloxane monomers or oligomers, preferably alkylsiloxane, optionally including a crosslinking agent and / or a catalyst, with solid particles of a polymeric material, homogenization of the assembly, ii) - placing the mixture obtained in step i) in an open mold, iii) - polymerization and crosslinking of the polysiloxane, preferably polyalkylsiloxane, to form the silicone-based matrix in which the solid polymer particles are dispersed.

The method is simple to implement and makes it possible to produce an implantable composite material in situ in the natural environment. In addition, the use of such a material is more economical because it requires only a single receiving phase and a single pre-concentration step.

BRIEF DESCRIPTION OF THE FIGURES The invention will be better understood on reading the following description of exemplary embodiments, with reference to the appended figures which are histograms showing the yields of extraction of pesticides, by comparing the yields of different receiving phases with those of the composite material according to the invention, more particularly:

FIG. 1 compares the Test1 and Test2 receptor phases with the PDMS / HLB material according to the invention;

FIG. 2 compares the PDMS / C12, PDMS / ABN, PDMS / MAX and PDMS / HLB receptor phases with the PDMS base matrix without polymeric solid particles;

FIG. 3 compares the PDMS / HLB receptor phase according to the invention with the PDMS basic matrix without polymeric solid particles and with HLB polymer particles alone.

EXAMPLES

Preparation of the receiving phases

Several receptor phases were prepared according to the method of the present invention (Example 1) or according to the method described in Kermani FR et al., Water Quality Research J. of Canada, pp 85-98, 2013 (Comparative Example 2 ).

Example 1

The silicone-based matrix is PDMS (polydimethylsiloxane) prepared using the Sylgard® 184 kit (Dow Corning). To the liquid mixture before polymerization are added the solid particles of different polymers, mentioned in Table 1 below, in the mass proportions of between 5 and 15%. After homogenization for about 15 minutes in order to properly integrate the particulate filler into the silicone oil mixture, the resulting mixture, which has a texture close to a "cake dough", is then left to stand for about an hour in a vacuum chamber at room temperature (20 ° C) to remove any air bubbles formed during mixing. Then the whole is transferred into a glass petri dish in a homogeneous layer of 3 mm thick, which is then placed as horizontally as possible in an oven at 80 ° C for at least 24 hours (instead of a recommended hour) by the manufacturer). For better crosslinking on both sides, the composite material is returned before the end of this period of 24 hours.

The various solid particles tested are either commercial polymers or polymers synthesized in the laboratory.

SDB: Styrene divinylbenzene

Table 1

All the materials tested are macroscopically homogeneous, except that containing the particles of MAX which had some roughness on the surface.

For the rest of the experiments and the results of Example 3, the prepared receptor phases are noted in abbreviated form, with parentheses in mass proportions matrix / particles: PDMS / HLB (85/15), PDMS / ABN (85/15) , PDMS / MAX (91/9) and PDMS / C12 (94/6).

Example 2 (comparative):

Silicone rods polymerized to PDMS without the addition of polymer particles were used as a support for the HLB polymer particles. The PDMS rods were soaked in a mixture of heptane and liquid PDMS (Sylgard®184 Kit) to act as "glue" on the silicone support. Two different proportions were tested (called Testl and Test2 in Table 2 below). A test in pure heptane was also performed (Test3). After depositing a film of this mixture, the rods are stirred in a test tube containing HLB particles (size 30 μm as in Example 1). The stems are then placed in petri dishes and placed as horizontally as possible in an oven at 80 ° C for at least 24 hours.

Table 2

The materials obtained according to this method No. 2 (Test1, Test2, Test3) are not completely homogeneous at the surface because of the difficulty in obtaining a homogeneous thin film. The amount of HLB phase fixed on these materials can be estimated by difference between the mass of the support (PDMS) before and after HLB phase deposition (Test1 = 26.6 mg, Test2 = 29.0 mg, Test3 = 1.0 mg ).

The retention capacities of the materials prepared according to the above two methods were then evaluated in the laboratory for several families of pesticides in the water.

Example 3

Twenty-five pesticides were selected to evaluate the retention capacity of synthesized materials. This list (Table 3) represents pesticides (fungicides, herbicides or insecticides) with a wide range in terms of polarity of the molecules (-0.06 <log KoW <5.51).

Source: University of Hertfordshire, Pesticide Properties DataBase, http://sitem.herts.ac.uk/aeru/footprint/en/index.htm

Table 3

All the new materials synthesized, presented in Tables 1 and 2, have been tested for their retention capacity for the molecules studied. An additional test was carried out with 30 micron HLB powder dispersed in solution (25 mg, the equivalent of the HLB mass contained in 170 mg of PDMS / HLB (85/15)).

To facilitate the comparison of the retention capacities of the synthesized materials, these were cut into rods (rectangular parallelepipeds) of approximately 20 x 3 x 3 mm for a weight of approximately 170 mg ± 2.5%, except for the materials of the method of Comparative Example 2 which weighs about 195 mg (170 mg of HLB coated PDMS).

The comparison was carried out batchwise in a brown glass flask containing 50 ml of Evian® water doped with 25 pesticides (individual concentration of the order of 1 to about 10 μg / l) in which a rod is introduced. to test. The solution is stirred with a magnetic bar covered with Teflon. Control vials (n = 3) make it possible to control the potential degradation of the molecules or the adsorption possibilities on the walls of the bottle and the magnetized bar. The measurement of the concentration of pesticides in water is carried out by direct injection into UHPLC-MS / MS.

A previous kinetic study confirmed that equilibrium was reached in 48 hours with PDMS depending on the molecule studied and a contact period of 7 days was chosen to take a margin of safety. The retention capacity for each pesticide studied was evaluated by calculation of the extraction yield per molecule and for a given material after 7 days of experimentation. The amount accumulated in the material is calculated by difference between the equilibrium aqueous concentration in the batch and the pesticide concentration in the control water under the same conditions. The extraction yield is obtained by calculating the ratio of the amount accumulated in the material to the amount of pesticides present in the aqueous phase of the control vial at the same time.

Appearance / holding of materials

Particles appeared on the surface of the water after 7 days of batch stirring for the materials Test1, Test2 and Test3; this phenomenon is particularly important for Test3. The "sticking" of the HLB particles on the surface of the silicone-based material is therefore not effective, the particles were partly separated from the material during the pesticide extraction tests; and this particularly when using only heptane (Test3).

The other materials, synthesized according to the process of the present invention (Example 1), for which the particulate polymeric materials were incorporated into the silicone-based matrix, have completely withstood any erosion that may be caused by agitation in the process. 'experimentation.

Sorption performance

The extraction yields calculated from the experiment are shown in Figures 1 and 2 provided in the appendix. The experiments were carried out in a single copy and the uncertainties calculated for the extraction yield (expressed with a standard deviation) are estimated thanks to the coefficients of variation of the concentration measurements in the control batches (n = 3). These results were compared with the extraction yields previously calculated in other experiments. The results are repeatable with coefficients of variation less than 15%.

With the HLB phase

When the receiver phases comprising HLB particles prepared with the methods of Examples 1 and 2 are compared, it is found that for masses close to HLB (Test I = 26.6 mg, Test2 = 29.0 mg and PDMS / HLB = 0.15 x 170 mg = 25.5 mg), the extraction yields of the pesticides studied are comparable, despite the fact that the particles prepared according to the process of the present invention lead to a composite material where a large part of the particles HLBs are incorporated within the PDMS matrix and do not appear on the surface of said matrix.

Surprisingly also, a greater extraction capacity (at least 10% higher) for the PDMS / HLB material seems to be released for four molecules: DCA, LINU, MTC and ATC. This result is probably related to a specific interaction between the composite material and these molecules according to their physicochemical properties. There would therefore be additional interactions that enhance sorption when the HLB phase is inserted into the silicone phase and not at the surface.

In addition, the synthesis protocol of composite material according to the invention by forming a homogeneous composite material has the advantage of being a simpler process to implement and repeatable than the deposition of a film on the surface, and leads to a material that allows to better fix the particulate phase. The result is a stronger material, which is very suitable for sampling in laboratory conditions and especially in the natural environment.

With the other phases

The best extraction yields are obtained with the HLB phase and the MAX phase, averaging at least 20% higher than other materials. The proportion of MAX phase is however lower than the proportion of HLB (9% against 15%) which would indicate that the MAX phase has an even greater sorption potential for pesticides than HLB (however, as indicated above the material PDMS / MAX has some roughness on the surface).

The C12 and ABN phases introduced in particulate form in the PDMS matrix also improve the sorption of pesticides compared to the PDMS alone but less intensively and for a smaller number of molecules.

Example 4

To try to understand the contribution of each phase (PDMS and HLB) for the sorption of pesticides with the composite material according to the invention, these materials were tested separately and in equivalent amount (PDMS = 170 mg, HLB = 25 , 5 mg and PDMS / HLB = 25.5 mg of HLB dispersed in 144.5 mg of PDMS). The HLB phase alone is tested in the dispersed state in the solution which maximizes the contact surface between this material and the pesticides.

The results, collected and presented in Figure 3, make the following observations. At comparable mass, PDMS has a significant affinity (R> 40%) only for molecules with a log Kow> 3 (and AZS); and this affinity is optimal (close to 100%) for molecules with a log Kow> 4.2. At equivalent HLB phase mass, extraction yields with the PDMS / HLB material are similar to those obtained with the HLB phase alone for the majority of molecules, that is to say close to 100%. The yields are less than about 20% for four molecules (DCPMU, DMM, NFZ-d, NFZ), which may be due to a lower availability of the HLB phase in the PDMS matrix compared to the HLB powder dispersed directly. in the aqueous medium. Nevertheless, the yields are at least 10% higher for five molecules (DFF, LINU, ATZ, DCA, SMZ). The improvement of the extraction yield for the FDF certainly seems logical because the PDMS has a better affinity for this molecule than the HLB phase. On the other hand, for LINU, ATZ, SMZ and especially DCA, the improvement results from a synergy between the two materials which is surprising.

Example 5 (comparative)

Rods of PDMS modified by addition of a PDMS-PEG (polyethylene glycol) copolymer were prepared. PEG is a polymer of hydrophilic nature.

The base of the modified PDMS rods is the Sylgard 184. kit. Ternary mixtures with the PDMS base, the 10% crosslinker (m / m) and different weight percentages of the PDMS / PEG copolymer were made. These mixtures are then heated under the same synthesis conditions as Examples 1 and 2. The hypothesis is that the polyethylene glycol imparts a hydrophilic character to the copolymer with the PDMS. The presence of oxygen atoms indeed favors dipole-dipole type interactions and hydrogen bonds. The PDMS-PEG copolymer retained for the modification of the PDMS rods is poly [dimethylsiloxane-co-methyl (3-hydroxypropyl) siloxane] -GT'aff-poly (ethylene glycol) ethyl ether (Sigma-Aldrich) which contains 80% by weight of polyethylene glycol units whose formula is shown below:

Rods having different proportions of the PDMS-PEG copolymer corresponding to 1, 3, 5 and 10% by weight of PEG are synthesized, in order to test the widening of the polarity range of the extracted pesticides.

Experiments with PDMS rods alone have shown good ability to extract some of the most hydrophobic pesticides, but most of the hydrophilic pesticides (log Kow <3) are little or not retained on PDMS rods.

The extraction capabilities of the PDMS / PEG rods were then tested (in triplicate) and compared to those of the PDMS rods. The tests performed for different percentages of each were designed to evaluate the effect of modifier concentration on pesticide extraction yields.

There is no significant difference in extraction yields regardless of the percentage of PDMS-PEG. In addition, a slight decrease in the extraction yields of the most hydrophobic molecules is observed for PDMS / PEG rods compared with PDMS. This can be explained by the fact that the modification with a more polar polymer causes a decrease in the affinity of the most hydrophobic pesticides for the stem. In conclusion, the modification of these stems with PEG did not, however, make it possible to increase the extraction yield of the most polar pesticides.

Claims (15)

1. Composite material for the sorption of both hydrophobic and hydrophilic molecules, characterized in that it comprises: an elastomer matrix based on silicone, capable of absorbing and / or adsorbing ions or molecules of a hydrophobic nature, in which is dispersed at least one polymeric material in the form of solid particles capable of absorbing and / or adsorbing hydrophilic ions or molecules. Composite material according to Claim 1, characterized in that the silicone-based elastomer matrix is formed predominantly of a polysiloxane, preferably a polyalkylsiloxane, such as polydimethylsiloxane (PDMS) or a polymethylsiloxane comprising vinyl groups and / or phenyl and / or fluorinated. 3. Composite material according to any one of the preceding claims, characterized in that the solid particles of polymeric material have a particle size less than or equal to 100 micrometers, preferably less than or equal to 60 micrometers, more preferably less than or equal to 30 micrometres. micrometers. 4. Composite material according to any one of the preceding claims, characterized in that said polymeric material forming the solid particles is chosen from: a polymer of divinylbenzene and / or N-vinylpyrrolidone, a styrene-divinylbenzene copolymer including hydroxyl groups , a divinylbenzene-N-vinylpyrrolidone copolymer including or not quaternary amine groups, a poly (meth) acrylate, alone or in a mixture. 5. Composite material according to any one of the preceding claims, characterized in that said polymeric material forming the solid particles is a polymer which has properties both hydrophobic and hydrophilic, such as a copolymer of divinylbenzene-N-vinylpyrrolidone. 6. Composite material according to any one of the preceding claims, characterized in that the solid particles of polymeric material are present in said silicone matrix in mass proportions of between 1% and 50%, preferably between 2 and 30%, more preferably between 5 and 15%, of the total mass of the matrix with the particles. 7. composite material according to any one of the preceding claims, characterized in that said solid particles of polymeric material are dispersed within the silicone-based matrix at least in a zone near the periphery of said matrix. 8. Composite material according to any one of the preceding claims, characterized in that said solid particles of polymeric material are distributed homogeneously throughout said matrix, preferably when said matrix is thin. Passive sampling for the sorption of both hydrophilic ions or molecules and hydrophobic ions or molecules by means of a receiving phase, characterized in that the receiving phase comprises the composite material according to any one of the preceding claims. . 10. Use of the composite material according to any one of claims 1 to 8 for the sorption of both hydrophilic ions or molecules and hydrophobic ions or molecules in a liquid medium, aqueous and / or organic, in a gaseous medium, in a sediments, in biological media or in food matrices. 11. Use of the composite material according to claim 10, for absorbing and / or adsorbing at the same time ions or molecules having an octanol / water partition coefficient: log Kow of between 0.0 and 10.0, preferably between 0 and 10. , 6 and 5.5. 12. Use according to claim 11, characterized in that said molecules comprise herbicides, fungicides, insecticides, organophosphorus compounds, aromatic hydrocarbons, such as polycyclic aromatic hydrocarbons (PAHs), organohalogen compounds such as polychlorinated biphenyls (PCBs), polybrominated biphenyls (PBBs), polychlorinated dibenzodioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), perfluorinated compounds (PFCs), detergents such as alkylphenols, surfactants, plasticizers such as phthalate and / or bisphenols, pharmaceuticals such as beta-blockers, anti-depressants, lipid-lowering agents, analgesics, antibiotics, bronchodilators, chemotherapy products, hormones, cosmetics, or a mixture of several of these . 13. Use of the composite material according to one of claims 10 to 12 for the pre-concentration of ions or hydrophilic and / or hydrophobic molecules in trace amounts. 14. Use of the composite material according to one of claims 10 to 12, for the depollution of an environment containing hydrophilic and / or hydrophobic ions or molecules. 15. A method of manufacturing a composite material according to any one of claims 1 to 8 comprising the following successive steps: i) - mixture of monomers or oligomers siloxane, preferably alkylsiloxane, optionally including a crosslinking agent and / or a catalyst, with solid particles of a polymeric material and homogenization of the assembly, ii) - placing the mixture obtained in step i) in an open mold, iii) - polymerization and crosslinking of the polysiloxane, preferably the polyalkylsiloxane, to form the silicone-based matrix in which the solid particles of polymeric material are dispersed.