FILTER COMPRISING A HYDROPHOBIC, OLEOPHILE, AND SUBLIMABLE COMPOUND, ITS PREPARATION PROCESSES AND USES

Abstract

The present invention relates to a filter comprising a hydrophobic, oleophilic, and sublimable compound, in particular superhydrophobic, superoleophilic, and sublimable, its preparation methods and its uses.

Description

Title of the invention: FILTER COMPRISING A HYDROPHOBIC, OLEOPHILIC, AND SUBLIMABLE COMPOUND, ITS PREPARATION METHODS AND ITS USES

[0001] The present invention relates to a filter comprising a hydrophobic, oleophilic, and sublimable compound, in particular superhydrophobic, superoleophilic, and sublimable, its preparation methods and its uses.

[0002] Water pollution by greases and oils in high concentrations is caused by many industrial sectors such as the food industry, petrochemicals, textiles, metallurgy, pharmaceuticals, biology, mechanics, paper industry, etc.

[0003] These fats and oils regularly cause irreparable damage to the environment and biological ecosystems, but also to water distribution networks. Indeed, they float on the surface of the water and degrade the biotope and the ecosystem by preventing the oxygenation of the environment, asphyxiating the fauna and flora. And when fats and oils accumulate in the network, they can damage it and risk releasing toxic gases, harming the health of sanitation personnel.

[0004] In this context, developments to find solutions that effectively separate these pollutants from water have accelerated in recent decades. Common techniques involve physical and chemical methods such as sedimentation, centrifugation, adsorption, absorption, etc. There are also biological methods using microorganisms to clean water or electrochemical techniques using electrolysis.

[0005] Among these techniques, absorbent materials are particularly studied because they have the advantage of not requiring energy for their implementation, of being simple to use and of not generating secondary pollution such as new liquid effluents to be treated. "Conventional" absorbent materials are generally divided into three categories: i) natural organic adsorbents, ii) inorganic adsorbents, iii) polymeric adsorbents. However, it is noted that in general, natural organic adsorbents have a low absorption capacity, inorganic adsorbents generate secondary pollution, and polymeric adsorbents have low hydrophobicity and low absorption efficiency.

[0006] The limitations of traditional separation technologies have led research to develop new materials, with specific wetting conditions to be more efficient. Among the techniques explored, electro-fabrication Spinning is studied because it allows the production of media composed of micro or nanofibers that can be formulated with a wide variety of materials (synthetic polymers, cellulose, titanium composites, silver, etc.). For example, different materials such as PLA (polylactic acid), CA, PEG (Polyetylene Glycol), PSU (Polysulfone) or PVDF (polyvinylidene fluoride) are studied for the manufacture of filters with the aim of obtaining recyclable products. However, these materials have disadvantages such as insufficient wetting performance, unsatisfactory mechanical properties, and low resistance to chemicals.

[0007] Thus, over the last decades, functional filters based on porous materials have been developed in many forms (membrane, periodic structure in the form of a 3D mesh, sponge, filter paper, etc.) with the aim of combining advantages such as low density, controlled wettability, high porosity, and a large specific surface area. Membrane separation has been a relatively active sector for its practical side because it allows both the interception and adsorption of the pollutant. This technique has the advantage of consuming little energy, being simple to implement, separating efficiently, and opening up new strategies for environmental decontamination.

[0008] For example, membrane filtration is used in the treatment of cutting fluids used in metalworking. These fluids are generally aqueous, used in the form of a “classic” emulsion (mineral oil based), a microemulsion (mineral oil and synthetic fluid) and finally a true solution (synthetic fluid). Used fluids present a very significant source of pollution which results in an impossible discharge of these fluids to a treatment plant. Membrane technology allows the production of a purified permeate (clarified and deoiled) which can be treated by the treatment plant.

[0009] After use, the filter containing the membrane filtration element becomes waste, the treatment of which depends on the material absorbed and the materials constituting the absorbent. In this context and in response to the increased interest in well-being, the notions of sustainability and respect for the environment, suppliers of filtration systems are striving to develop new filter media with recyclable materials, without toxic products, with the lowest possible environmental impact and which, ideally, would ultimately be a waste that can be recovered elsewhere or biodegradable. A typical recycling chain for oil-contaminated filters includes, after implementation of the filters, collection and transport, sorting and draining, grinding and recovery of the oil, and finally the recovery of the material or energy.

[0010] It should be noted, however, that this recycling chain can be improved since the filters are ultimately destroyed and the materials recovered for recycling are not not necessarily to manufacture new filters. This chain is therefore more part of a so-called linear economy (extract, manufacture, consume, throw away) than in a truly circular economy (eco-design, responsible consumption, extending the product's lifespan, sorting / recycling).

[0011] One objective of the invention is thus to provide new filters for filtering greases and oils while being able to be easily recycled, particularly within the framework of a circular economy.

[0012] Thus, the invention relates to a filter consisting of, or comprising a filter support and on its surface, a hydrophobic, oleophilic, and sublimable compound.

[0013] Said compound can thus be removed by sublimation and reapplied to new filter supports or in filter molds, easily and without loss of properties of the new filters obtained.

[0014] By "filter" is meant in particular a device, namely a filtering medium, in contact with which in particular water contaminated with oil is capable of being de-oiled.

[0015] This filter can therefore comprise a filter support, which carries on all or part of its surface the hydrophobic, oleophilic, and sublimable compound. In this case, the filter (which can also be called “filter medium”) comprises the filter support and the hydrophobic, oleophilic, and sublimable compound.

[0016] In another case, this filter is made up of said hydrophobic, oleophilic, and sublimable compound. In this case, the filter is devoid of filter support. It is the compound itself which forms the filter.

[0017] By "hydrophobic compound" is meant in particular a compound for which the contact angle of a drop of water on the surface of said compound is greater than or equal to 70°.

[0018] The hydrophobic compound may, for example, be weakly hydrophobic, moderately hydrophobic, strongly hydrophobic, or superhydrophobic.

[0019] By "weakly hydrophobic compound" is meant in particular a compound for which the contact angle of a drop of water on the surface of said compound is greater than or equal to 70°, and less than 90°.

[0020] By "moderately hydrophobic compound" is meant in particular a compound for which the contact angle of a drop of water on the surface of said compound is greater than or equal to 90°, and less than 120°.

[0021] By "strongly hydrophobic compound" is meant in particular a compound for which the contact angle of a drop of water on the surface of said compound is greater than or equal to 120°, and less than 150°. By "superhydrophobic compound" is meant in particular a compound for which the contact angle of a drop of water on the surface of said compound is greater than or equal to 150°.

[0022] This contact angle can be measured by techniques well known to man of the trade, for example by goniometry. This is a technique which typically consists of depositing a small liquid drop, for example with a volume of 1 to 10 pl, on the surface and measuring the angle formed between the tangent to the drop at the point of contact and the surface).

[0023] By "oleophilic compound" is meant in particular a compound for which the contact angle of a drop of oil, for example hexadecane, on the surface of said compound is less than or equal to 60°.

[0024] The oleophilic compound may, for example, be weakly oleophilic, moderately oleophilic, strongly oleophilic, or superoleophilic.

[0025] By "weakly oleophilic compound" is meant in particular a compound for which the contact angle of a drop of oil, for example hexadecane, on the surface of said compound is greater than 30 and less than or equal to 60°.

[0026] By "moderately oleophilic compound" is meant in particular a compound for which the contact angle of a drop of oil, for example hexadecane, on the surface of said compound is greater than 10 and less than or equal to 30°.

[0027] By "highly oleophilic compound" is meant in particular a compound for which the contact angle of a drop of oil, for example hexadecane, on the surface of said compound is greater than 5 and less than or equal to 10°.

[0028] By "superoleophilic compound" is meant in particular a compound for which the contact angle of a drop of oil, for example hexadecane, on the surface of said compound is less than or equal to 5°.

[0029] This contact angle can be measured by techniques well known to those skilled in the art, for example by goniometry, as described above.

[0030] A person skilled in the art will be able to adapt the interaction time between the fluid to be filtered and the filtering medium depending on the more or less hydrophobic character (from weakly hydrophobic to superhydrophobic) and the oleophilic character (from weakly oleophilic to superoleophilic), to obtain the desired filtration efficiency.

[0031] By "sublimable compound" is meant a compound capable of sublimating, in particular at a temperature of 0 to 150°C.

[0032] This sublimation can be carried out at atmospheric pressure, for example approximately 1013.25 hPa, or at a pressure lower than atmospheric pressure, in particular at a pressure lower than the saturated vapor pressure of the compound at the temperature considered, in particular under vacuum, for example at a pressure lower than 100, 10, 1, or even 0.1 Pa.

[0033] According to one embodiment, the hydrophobic compound is a superhydrophobic compound.

[0034] According to one embodiment, the oleophilic compound is a superoleophilic compound.

[0035] According to one embodiment, the invention relates to a filter consisting of, or

[0036]

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[0041]

[0042]

[0043] comprising a filter support and on its surface, a superhydrophobic, super-oleophilic, and sublimable compound. According to one embodiment, the filter as defined previously comprises a filter support and on its surface, a hydrophobic, oleophilic, and sublimable compound, in particular superhydrophobic, superoleophilic, and sublimable. According to a particular embodiment, the filter support is made of or comprises a material chosen from: - Polymers, in particular chosen from polypropylene (PP), polycarbonate (PC), poly(methyl methacrylate) (PMMA), Nylon, polyetheretherketone (PEEK), polyethylene (PE), for example high density polyethylene (HDPE), poly(vinyl chloride) (PVC), polyurethane (PU), and their mixtures; - Natural materials, notably chosen from cotton, rice husk, coconut fibers, hemp, and their mixtures; - Metals, in particular chosen from aluminum, nickel, copper, steel, and their alloys; - Ceramic materials, in particular based on silica, zirconia, titanium oxide, alumina, or their mixtures; - Composite materials, in particular composite materials comprising carbon fibers, glass fibers and / or natural fibers, for example of a natural material as defined above, and an organic matrix, in particular polymer, ceramic and / or metallic, for example of a material as defined above. According to a particular embodiment, the filter support is in the form of fibers, powder, granules, plate(s), sheet(s), membrane(s), periodic structure in the form of a 3D mesh, sponge, or filter paper. According to a more particular embodiment, the filter support is in the form of fibers. The fibers may be made of or include synthetic, organic, inorganic, composite materials or mixtures thereof. These may, for example, be textile fibres, the diameter of which is in particular between 10 and several hundred microns, micro-textile fibres, the diameter of which is in particular between 1 and 10 pm, or nanometric fibres, the diameter of which is in particular between 10 nm and several hundred nm. The fiber filter media have in particular: - a thickness ranging from 2 to several tens of mm; - a porosity of 80 to 98%; and / or - a weight ranging from 50g / m2 to 1500g / m2. According to another more particular embodiment, the filter support is in the form of powder.

[0044] These powders can be ceramic, mineral, polymer, composite powders, or mixtures thereof.

[0045] The particle size of the powders is in particular understood: - from 0.1 to 5 pm, in particular for so-called high-efficiency filter supports; - from 5 to 20 pm, in particular for so-called standard filter supports; - from 20 to 50 pm, in particular for so-called economical filter supports; or - from 50 pm to 1 mm, in particular for so-called coarse filter supports.

[0046] The porosity of the filter supports in powder form is in particular approximately 40%, in particular for so-called high-efficiency filter supports, or between 50 and 60%, in particular for so-called standard filter supports.

[0047] According to another more particular embodiment, the filter support is in the form of granules.

[0048] These granules can have a diameter of 0.5 to 2 mm, in particular for so-called standard filter supports, or of 0.1 to 0.5 mm, in particular for so-called high-performance filter supports.

[0049] According to another more particular embodiment, the filter support is in the form of plate(s).

[0050] The plates may be made of or comprise a material selected from ceramic, metal, polymer, and / or composite.

[0051] The plates may in particular be square or rectangular plates.

[0052] The largest dimension of these plates, in particular the diagonal for square or rectangular plates, is between 5 and several tens of cm or even several meters.

[0053] The filter support may comprise a plurality of plates, in particular parallel plates, in particular spaced 1 to 5 mm apart.

[0054] According to another more particular embodiment, the filter support is in the form of sheet(s).

[0055] The sheets may be made of or comprise a material selected from organic, inorganic, composite materials, or mixtures thereof.

[0056] The sheets have in particular a thickness of 50 to 200 μm.

[0057] The pore size of the sheets is for example from 0.1 to 10 nm (in particular in the context of microfiltration), 1 to 100 nm (in particular in the context of ultrafiltration), or less than 1 nm (in particular in the context of nanofiltration).

[0058] According to another more particular embodiment, the filter support is in the form of membrane(s).

[0059] The membranes may be made of or comprise a material selected from ceramics, polymers, composites, and mixtures thereof.

[0060] The pore size of the membranes is for example from 0.1 to 100 nm (in particular in the context of microfiltration), 1 to 100 nm (in particular in the context of ultrafiltration), or less than 1 nm (in particular in the context of nanofiltration).

[0061] According to another more particular embodiment, the filter support is in the form of a periodic structure in the form of a 3D mesh.

[0062] As an example, the mesh of the periodic structure can be chosen from the meshes

[0063] cubic, quadratic, orthorhombic, monoclinic, triclinic, rhombohedral, hexagonal, and / or random.

[0064] The periods along the 3 orthogonal axes can be from 0.01 mm to 10 mm.

[0065] According to another more particular embodiment, the filter support is in the form of a sponge.

[0066] Sponges typically have random open porosity, pores from a few hundred nm to a few hundred microns, porosity rate from 5 to 60%

[0067] According to another more particular embodiment, the filter support is in the form of filter paper.

[0068] The weight of such a filter paper is in particular from 100 to 300 g / m2 (in particular for medium filters), from 300 to 700 g / m2 (in particular for fine filters), or greater than 700 g / m2 (in particular for ultrafilters).

[0069] According to a particular embodiment, the ratio R of the mass of compound to the total mass of the filter is greater than or equal to 0.1%, and less than 100%.

[0070] According to one embodiment, the filter as defined above consists of a hydrophobic, oleophilic, and sublimable compound, in particular superhydrophobic, super-oleophilic, and sublimable.

[0071] According to a more particular embodiment, the filter support is in the form of granules, flakes or plate(s). According to another more particular embodiment, the filter has a specific surface area of ​​from 1 m2 / g to 10000 m2 / g, in particular 100 to 2000 m2 / g.

[0072] According to another more particular embodiment, the filter has a roughness Ra of from 0.1 to 10 pm.

[0073] According to a particular embodiment, the compound is cyclododecane.

[0074] According to a particular embodiment, the invention relates to a filter as defined previously for water deoiling.

[0075] According to another aspect, the invention also relates to the use of a hydrophobic, oleophilic and sublimable compound, in particular superhydrophobic, superoleophilic and sublimable, for the preparation of a filter.

[0076] All the embodiments mentioned above with regard to the filter also apply alone or in combination, for the following.

[0077] According to a particular embodiment, the filter is a filter for de-oiling water.

[0078] According to a particular embodiment, the filter is a recyclable filter and / or one made from recycled compound.

[0079] According to another aspect, the invention also relates to a method for preparing a filter as defined above, which comprises a step of depositing a hydrophobic, oleophilic and sublimable compound, said compound being in particular superhydrophobic and / or superoleophilic.

[0080] This deposition can be carried out using techniques well known in the prior art.

[0081] According to a particular embodiment, the filter comprises a filter support and at its surface, a hydrophobic, oleophilic, and sublimable compound, in particular superhydrophobic, superoleophilic, and sublimable, and the deposition step is a step of impregnating a filter support with said hydrophobic, oleophilic and sublimable compound, a step of dipping a filter support in said hydrophobic, oleophilic and sublimable compound, or a step of projection or application, for example using a brush, roller, sprayer or other, of said hydrophobic, oleophilic and sublimable compound on a filter support.

[0082] According to a particular embodiment, the deposition step is carried out using a solution of the compound in a solvent, for example hexane and / or heptane.

[0083] Solvents such as, for example, hexane or heptane make it possible to obtain, if necessary, very concentrated solutions, in particular up to 98% (v / v).

[0084] According to a particular embodiment, the impregnation, dipping or projection or application is carried out at a temperature of 10 to 50°C, and / or under a pressure of 1 mbar to 100 bar, in particular at atmospheric pressure.

[0085] Atmospheric pressure means in particular a pressure of 1013.25 hPa or 1 atm.

[0086] This temperature (this also being true for the pressure) is the temperature at which the deposition itself is carried out, for example the temperature of the atmosphere in which the deposition takes place.

[0087] According to a particular embodiment, the filter comprises a filter support and on its surface, a hydrophobic, oleophilic, and sublimable compound, in particular superhydrophobic, superoleophilic, and sublimable, and the deposition step is a step of liquid or solid condensation on a filter support of said hydrophobic, oleophilic and sublimable compound.

[0088] This deposition by condensation can be carried out at atmospheric pressure, by varying the deposition temperature, as is well known to those skilled in the art.

[0089] More generally, those skilled in the art know how to obtain the desired condensation deposition rate as required by varying the temperature and / or pressure applied.

[0090] For example, to accelerate deposition by condensation, it is possible to work at low temperature and overpressure.

[0091] According to a particular embodiment, the condensation takes place at a temperature of -20°C to 20°C, in particular from 0 to 10, 15°C, and / or under a pressure of 1 bar to 100 bar, in particular at atmospheric pressure.

[0092] According to a particular embodiment, the filter is made up of a superhydrophobic, superoleophilic, and sublimable compound, in particular superhydrophobic, superoleophilic, and sublimable, and the deposition step is a step of deposition of said compound in a mold of said filter.

[0093] According to a particular embodiment, the deposition is carried out at a temperature of 18 to 25°C, and / or under a pressure of 1 bar to 100 bar, in particular at atmospheric pressure.

[0094] According to another aspect, the invention also relates to a method for recycling a filter as defined above, which comprises (i) a step of sublimation of said compound.

[0095] The contaminants of the filter, in particular the oils as defined in the present description, are not capable of being sublimated, allowing the obtaining of the superhydrophobic, superoleophilic, and sublimable compound, in particular superhydrophobic, superoleophilic, and sublimable, in the pure state, in particular ready without any other purification step for the preparation of other filters according to the invention.

[0096] Sublimation is also likely to leave the surface of the filter media intact.

[0097] This sublimation can be carried out at atmospheric pressure, by varying the deposition temperature, as is well known to those skilled in the art.

[0098] More generally, those skilled in the art know how to obtain the desired sublimation speed as required by varying the temperature and / or pressure applied.

[0099] For example, to accelerate sublimation, it is possible to increase the temperature and work at low pressure.

[0100] According to a particular embodiment, the sublimation takes place at a temperature of from 20 to 100°C, and / or under a pressure of from 1 mbar to 1 bar, in particular at a temperature of from 40 to 70°C and / or at atmospheric pressure.

[0101] The sublimation of the compound can for example be characterized by measuring the variation of its mass over time by determining the change in mass between two weighings.

[0102] According to another aspect, the invention also relates to a method of recycling a filter as defined above, which comprises, after step (i), a step (ii) of preparing a filter as described above, in which the compound is at least partially that obtained at the end of step (i).

[0103] In this case, the compound sublimed in the recycling process is deposited as described in relation to the preparation process. In particular, when the filter comprises a filter support, the latter is distinct in the two processes.

[0104] The hydrophobic, oleophilic, and sublimable compound, in particular superhydrophobic, superoleophilic, and sublimable, obtained at the end of step (i) can be condensed to be stored and used later, in particular during a filter preparation process according to the invention.

[0105] The hydrophobic, oleophilic, and sublimable compound, in particular superhydrophobic, superoleophilic, and sublimable, obtained at the end of step (i), in the gaseous state, can be directly used in the filter preparation process according to the invention, as defined above, for example by condensation.

[0106] Examples of such recycling methods according to the invention are illustrated in Figures 1 and 2.

[0107] According to another aspect, the invention also relates to the use of a filter as described above, for deoiling water.

[0108] This water is contaminated with oil.

[0109] This contamination can be: - from a few ppm (parts per million, or mg / L) to around a hundred ppm, particularly for slightly contaminated water, for example runoff water around industrial areas, or rainwater falling on oil / gas sites; - from 100 to 1000 ppm, particularly for moderately contaminated water, for example wastewater from service stations, mechanical maintenance activities, or vehicle washing; - above 1000 ppm, particularly for highly contaminated water, for example drainage water around crude oil storage areas, industrial effluents coming directly from petroleum processes.

[0110] By “oil” is meant at least one compound in the form of oil, which is in particular derived from the industrial sector, such as the food industry, petrochemicals, textiles, metallurgy, pharmaceuticals, biology, mechanics, or the paper industry.

[0111] This oil can be: - Free; it floats on the surface of the water (its density being lower than that of water); - Dispersed; the size of the oil drops dispersed in the water being in particular from 100 to 1000 pm; - Emulsified; the size of the oil drops dispersed in the water being in particular from 1 to 100 pm; - Dissolved; the size of the oil drops dissolved in water being notably less than Ipm.

[0112] According to another aspect, the invention also relates to a method for de-oiling water comprising a step of bringing a filter as defined above into contact with water contaminated with oil.

[0113] According to a particular embodiment, the contacting takes place at a temperature of 5 to 50°C, and / or for a duration of 1s to 10min.

[0114] This duration, corresponding in particular to the so-called residence time of the oil-contaminated water in the filter, or of contact of the oil-contaminated water with the filter, depends, as is well known to those skilled in the art, and generally: - the fluid flow rate (oil-contaminated water): the higher the flow rate, the shorter the residence time; - filter design; - where applicable, the size of the pores of the filter: the finer the pores, the greater the fluid takes time to pass through them; - the filter pressure drop: the higher it is, the longer the residence time. DEFINITIONS

[0115] As used herein, the value ranges in the form of "xy" or "from x to y" or "between x and y" include the bounds x and y, as well as the integers between these bounds. For example, "1-5", or "from 1 to 5" or "between 1 and 5" designates in particular the integers 1, 2, 3, 4 and 5. Preferred embodiments include each individual integer in the value range, as well as any subcombination of these integers. For example, preferred values ​​for "1-5" may include the integers 1, 2, 3, 4, 5, 1-2, 1-3, 1-4, 1-5, 2-3, 2-4, 2-5, etc.

[0116] As used herein, the term "about" refers to a range of values ​​within ± 10% of a specific value. For example, the term "about 20" includes values ​​of 20 ± 10%, or values ​​from 18 to 22.

[0117] For the purposes of this description, percentages refer to percentages by mass relative to the total mass of the formulation, unless otherwise indicated. FIGURES

[0118] [Fig. 1] illustrates an example of circular recycling according to the present invention.

[0119] The steps in this example of a recycling chain are as follows:

[0120] (1) Use: Implementation of new or recycled filters functionalized with the 3S material (a superhydrophobic, superoleophilic, and sublimable compound), according to the invention;

[0121] (2) Collection and transport;

[0122] (3) Sorting, draining and extraction of oil: Manual sorting is carried out to separate the different filter categories. Draining allows the oil contained in the filters to be recovered. A centrifugation step or other physicochemical action (optional) can be applied in addition to extract the oil remaining after draining (will depend on the viscosity of the oil or the mixture considered). The collected oil can be regenerated in a specialized plant in step (4).

[0123] (4) Removal of 3S material from de-oiled filters: Freed from oil in step previous, the 3S material can be recovered for reuse. The material is for example sublimated at room temperature or near and condensed on a new filter in step (5).

[0124] (5) Surface functionalization with 3S material of new filters: The material 3S in its gas phase is deposited on the filter surface by condensation. The 3S material in the gas phase comes in particular from step (4). Another option is to impregnate the filter support with the 3S material in its liquid phase.

[0125] (6) The functionalized filters are then conditioned and packaged to be repackaged. used and subsequently recycled in a truly circular economic loop, minimizing raw materials, energy consumed, waste and discharges, extending use, developing new jobs, etc.

[0126] [Fig.2] illustrates another example of circular recycling according to the present invention.

[0127] The steps in this example of a recycling chain are as follows:

[0128] (1) Use: Implementation of new or recycled filters functionalized with the 3S material (a superhydrophobic, superoleophilic, and sublimable compound), according to the invention;

[0129] (2) Collection and transport;

[0130] (3) Removal of 3S material from filters: The 3S material can be removed from the filters by sublimation. The material is for example sublimated at or near room temperature and further condensed for storage and later reuse or directly into a new filter in step (5) depending on the design of the plant and filters;

[0131] (4) Sorting, draining and extraction of oil: Manual sorting is carried out to separate the different filter categories. Draining allows the oil contained in the filters to be recovered. A centrifugation step or other physicochemical action (optional) can be applied in addition to extract the oil remaining after draining (will depend on the viscosity of the oil or the mixture considered). The collected oil can be regenerated in a specialized plant in step (4).

[0132] (5) Surface functionalization with 3S material of new filters: The material 3S in its gas phase is deposited on the filter surface by condensation. The 3S material in the gas phase comes in particular from step (4). Another option is to impregnate the filter support with the 3S material in its liquid phase.

[0133] The functionalized filters are then conditioned and packaged to be used again and subsequently recycled in a truly circular economic loop, minimizing raw material, energy consumed, waste and discharges, extending use, developing new jobs, etc. EXAMPLES

[0134] Example 1: Protocol for manufacturing a membrane from cotton impregnated with cyclododecane

[0135] A filter according to the invention was obtained as follows:

[0136] 1) Put 1g of cyclododecane (in flakes) in an aluminum mold and heat to 90°C on a hotplate;

[0137] 2) Once the cyclododecane is liquid, introduce a cotton square, the cyclo liquid dodecane impregnates the cotton;

[0138] 3) Once the cotton is impregnated, it is brought back to room temperature.

[0139] A drop of water placed on the cotton square impregnated with cyclododecane shows that the surface of the filter thus obtained is superhydrophobic according to the present invention.

[0140] Furthermore, a drop of hexadecane deposited on the cotton square impregnated with cyclododecane shows that the surface of the filter thus obtained is superoleophilic according to the present invention.

[0141] Example 2: Protocol for manufacturing a membrane obtained by condensation of cyclododecane on cotton

[0142] Another filter according to the invention was obtained as follows: 1. Put 1g of cyclododecane (in flakes) in a glass or aluminum dish; 2. Place the cup in a sealed enclosure at 30-40°C with a cotton square inside placed on a thermoelectric cooling system (Peltier module) 3. Once the cyclododecane is in a gaseous state, adjust the temperature of the cotton using the Peltier module to a temperature of 5°C to proceed with the condensation of the cyclododecane on the cotton square.

[0143] Here again, a drop of water placed on the cotton square impregnated with cyclododecane shows that the surface of the filter thus obtained is superhydrophobic according to the present invention.

[0144] And a drop of hexadecane placed on the cotton square impregnated with the cyclo- dodecane shows that the surface of the filter thus obtained is superoleophilic according to the present invention.

[0145] Example 3: Protocol for manufacturing a cyclododecane membrane

[0146] 1) Put 1g of cyclododecane (in flakes) in an aluminum mold and heat to 90°C on hot plate;

[0147] 2) Once the cyclododecane is liquid, remove the mold from the hotplate and place it on a cold surface, for example at a temperature of 10-15°C;

[0148] 3) Unmold the membrane which is ready to be used.

[0149] The rough surface of the membrane can be observed under an optical microscope.

[0150] Here again, a drop of water placed on the cotton square impregnated with cyclododecane shows that the surface of the filter thus obtained is superhydrophobic according to the present invention.

[0151] And a drop of hexadecane deposited on the cotton square impregnated with cyclododecane shows that the surface of the filter thus obtained is superoleophilic according to the present invention.

[0152] Example 4: Demonstration of the selective absorption capacity of cotton impregnated with cyclododecane according to Example 1

[0153] Protocol:

[0154] - Insert the membrane into the water contaminated with oil (2 ml of oil in 20 ml of water);

[0155] - Leave the membrane in the contaminated water for 2 minutes;

[0156] - Remove the membrane that has separated the oil from the water by absorption.

[0157] For the cotton control not treated with the 3S material, the oil remained in the water and there was no separation. In the case of the cotton membrane impregnated according to the invention, the oil is completely absorbed.

[0158] Example 5: Demonstration of the selective absorption capacity of the membrane manufactured from cyclododecane according to Example 3

[0159] Protocol:

[0160] - Insert the membrane into the water contaminated with oil (2 ml of oil in 20 ml of water);

[0161] - Leave the membrane in the contaminated water for 2 minutes;

[0162] - Remove the membrane containing the oil from the water.

[0163] Here too, the oil is completely absorbed after contact with the membrane of the invention.

[0164] Example 6: Demonstration of the ability to transfer by sublimation the 3S material of the invention

[0165] In its gas phase, the 3S material can condense on a cold surface.

[0166] Protocol:

[0167] - Positioning of Ci2H24, granulometry >100qm, on a heating plate at 60°C opposite a container containing ice.

[0168] - After a few minutes, the Ci2H24 is condensed on the cold part.

Claims

Claims

1. Filter consisting of, or comprising a filter support and on its surface, a hydrophobic, oleophilic, and sublimable compound.

2. Filter according to claim 1, comprising a filter support and on its surface, a hydrophobic, oleophilic and sublimable compound.

3. Filter according to claim 2, wherein the filter support is made of or comprises a material chosen from: - Polymers, in particular chosen from polypropylene (PP), polycarbonate (PC), poly(methyl methacrylate) (PMMA), Nylon, polyetheretherketone (PEEK), polyethylene (PE), for example high density polyethylene (HDPE), poly(vinyl chloride) (PVC), polyurethane (PU), and mixtures thereof; - Natural materials, in particular chosen from cotton, rice husk, coconut fibers, hemp, and mixtures thereof; - Metals, in particular chosen from aluminum, nickel, copper, steel, and alloys thereof; - Ceramic materials, in particular based on silica, zirconia, titanium oxide, alumina, or mixtures thereof;- Composite materials, in particular composite materials comprising carbon fibers, glass fibers and / or natural fibers, for example of a natural material as defined above, and an organic matrix, in particular polymer, ceramic and / or metallic, for example of a material as defined above.;

4. A filter according to any one of claims 1 to 3, wherein the filter support is in the form of fibers, powder, granules, plate(s), sheet(s), membrane(s), periodic structure in the form of a 3D mesh, sponge, or filter paper.

5. Filter according to any one of claims 1 to 4, in which the ratio R of the mass of compound to the total mass of the filter is greater than or equal to 0.1%, and less than 100%.

6. Filter according to claim 1, consisting of a hydrophobic, oleophilic and sublimable compound.

7. Filter according to claim 6: in which the filter media is in the form of granules, of flakes or plate(s); - which has a specific surface area of ​​from 1 m2 / g to 10000 m2 / g, in particular 100 to 2000 m2 / g; and / or - which has a roughness Ra of from 0.1 to 10 pm.

8. A filter according to any one of claims 1 to 7, wherein the compound is cyclododecane.

9. A method of preparing a filter according to any one of claims 1 to 8, which comprises a step of depositing a hydrophobic, oleophilic and sublimable compound, the depositing step being in particular, when the filter comprises a filter support and on its surface, a hydrophobic, oleophilic and sublimable compound: - a step of impregnating a filter support with said hydrophobic, oleophilic and sublimable compound, - a step of dipping a filter support in said hydrophobic, oleophilic and sublimable compound, - a step of spraying or applying, for example using a brush, roller or the like, said hydrophobic, oleophilic and sublimable compound onto a filter support, - a step of liquid or solid condensation on a filter support of said hydrophobic, oleophilic and sublimable compound, - or the depositing step being in particular, when the filter consists of a superhydrophobic, superoleophilic compound,and sublimable: a step of depositing said compound in a mold of said filter.,

10. A method of recycling a filter according to any one of claims 1 to 8, which comprises (i) a step of sublimation of said compound.

11. Recycling method according to claim 10, comprising, after step (i), a step (ii) of preparing a filter according to claim 9, in which the compound is that obtained at the end of step (i).

12. A method of deoiling water comprising a step of contacting a filter according to any one of claims 1 to 8 with oil-contaminated water.