WO2016142443A2

WO2016142443A2 - Method for the removal of organic contaminants from water

Info

Publication number: WO2016142443A2
Application number: PCT/EP2016/055070
Authority: WO
Inventors: Erik KIEKENS; Nils DE VOS
Original assignee: Avore Nv
Priority date: 2015-03-10
Filing date: 2016-03-10
Publication date: 2016-09-15
Also published as: WO2016142443A3; EP3268314A2; BE1022987A1; BE1022987B1

Abstract

The invention is related to a method for removing organic contaminants from water comprising the steps of: - bringing water that contains organic contaminants into contact with a thermoplastic elastomer and applying a force field, and/or a mechanical force to the thermoplastic elastomer while it is in contact with the water; - separating the water, with a reduced concentration of organic contaminants, from the thermoplastic elastomer.

Description

METHOD FOR THE REMOVAL OF

ORGANIC CONTAMINANTS FROM WATER

Field of the invention.

[0001] The invention concerns a method for the removal of organic contaminants from water.

State of the art.

[0002] Overexploitation of natural resources and the widespread use of chemicals have led to the accumulation of pollutants in our environment. Over the last few decades, air, ground, and water pollution have received more and more attention because of their adverse impacts on ecosystems and the health of humans and animals.

[0003] Substantial volumes of organic fluids, which are used worldwide in the form of fuel, lubricants, chemicals, solvents, pesticides, insecticides, etc., pollute our planet and cause disconcerting levels of contamination.

[0004] The increase in the global transport of oil means that oil spills and slicks are an increasing problem, not only from an economic standpoint, but also because of the ecological impact of the oil and products used to remove the oil.

[0005] The phytotoxicity of some chemicals poses an acute threat to marine fauna, among other things.

[0006] Recent studies have uncovered the presence of small amounts of hormones and endocrine disruptors, pharmaceuticals, and personal care products in surface waters, waste water, and drinking water.

[0007] Endocrine disruptors are of particular interest, which mimic the feminising effects of female (oestrogen) sex hormones. Synthetic oestrogens are primarily present in contraceptives and in preparations for hormone replacement therapy. Synthetic oestrogens are more stable than natural oestrogens, do not biodegrade in a natural way, and consequently find their way into the environment.

[0008] Various methods are known for the treatment of polluted water, including mechanical methods such as natural flotation, forced flotation, filtration, centrifugal gravity separation; electromagnetic methods such as ultrasound, electrolytic methods and separation methods based on electrophoresis; other physical and chemical methods are known such as those based on adsorption, absorption, ion exchange, and coagulation; as well as biological separation methods using microorganisms.

[0009] The conventional treatment methods for the purification of polluted water have already been described in the technical and patent literature.

[0010] US 3,518,183 describes a process for the removal of oil films from the contaminated water surface, wherein finely divided block copolymer is applied to the oil film and after which the oil-impregnated block copolymer is removed from the water. The block copolymer is a copolymer of monovinyl arenes and conjugated dienes, consisting of at least two non-elastomeric monovinyl arene polymer blocks separated by a conjugated diene block.

[0011] US 4,801 ,386 describes a method for the removal of organic and/or inorganic components from water, by making use of a porous material comprised of strands, which consist of a mixture of a thermoplastic material and an inorganic component such as barium sulphate, talc, or silica. The thermoplastic material is a homopolymer or copolymer of ethylene, propylene, styrene, butadiene, isoprene, vinyl chloride, vinyl acetate, and acrylonitrile.

[0012] US 4,941 ,978 describes a method for the removal of oil contamination from water in which an elastomer, consisting of a styrene-ethylene/butylene diblock or triblock copolymer containing 20 to 40 percent styrene, is added to the contaminated water.

[0013] US 6,541 ,569 describes an absorbent polymer material, consisting of a mixture of a block copolymer and a copolymer in which the block copolymer is selected from the group consisting of styrene-butadiene-styrene, styrene-butadiene, and styrene-isoprene- styrene, and in which the copolymer is an ethylene-propylene copolymer. The specific polymer materials will be used for the isolation of hydrocarbon-like contaminants from water.

[0014] US 7,297,267 describes an oil-absorbing filter element, consisting of a first portion which contains a unitary permeable oleophilic medium of a first polymeric material, and a second portion, which contains particles of a second oleophilic polymer. Both oleophilic polymers are thermoplastic elastomers, selected from the group consisting of styrene-ethylene/butylene-styrene, styrene-ethylene/propylene-styrene, styrene-butadiene- styrene, and styrene-isoprene-styrene block copolymers, and combinations thereof. The filter element enables the isolation of oils, hydrocarbons, solvents, and other contaminants from a contaminated water stream. [0015] US 6,582,608 describes a method for the removal of organic contaminants from liquids in which the contaminated fluids are brought into contact with dimensionally-stable particles of a polymer mixture, consisting of 55 to 95 percent by weight of a thermoplastic elastomer, from 5 to 45 percent by weight of a thermoplastic polymer, and from 0 to 12 percent by weight of a filler. The thermoplastic elastomer is selected from the group consisting of polystyrene-butadiene copolymers, polystyrene-butadiene-polystyrene triblock copolymers, polystyrene-isoprene-polystyrene triblock copolymers, and polystyrene grafts of thermoplastic polymers. The thermoplastic polymer is a polystyrene, a polyolefin, or mixtures thereof.

[0016] WO 82/02342 describes a process for removing at least one hydrocarbon composition from a mixture containing this hydrocarbon composition, during which the mixture is brought into contact with at least one elastomer, under conditions that cause the elastomer to absorb at least one portion of the hydrocarbon composition. The mixture may be a water/hydrocarbon mixture. An embodiment of the invention is the removal of hydrocarbons from water, such as waste water. The elastomer is a natural, recycled, vulcanised or synthetic rubber. Examples of synthetic elastomers are styrene-butadiene rubber, butyl rubber, nitrile rubber, ethylene-propylene copolymers, fluorine elastomers, and polyacrylates.

[0017] The use of ultrasonic vibration energy for the treatment of waste water is already known.

[0018] US 3,537,655 describes a method for the treatment of waste water such as sewage water, by the mechanical grinding of solid particles present in the waste water, then fractionating the resulting particles further, and partially sterilising the water by means of ultrasonic vibration energy.

[0019] WO 2013/043046 concerns an ultrasonic separator for the separation of sludge particles from a liquid in which a liquid channel, provided with an inlet and an outlet comprises one or more probes for obtaining a three-dimensional structure of nodes, which captures the particles and consequently separates them from the liquid.

[0020] US 4,961 ,860 describes a method for the destruction of dangerous microorganisms in water, wherein the water is isolated in a holding tank and is then subjected to ultrasonic vibrations set at a frequency between 15 and 150 kHz for a period of at least 12 seconds. The ultrasonic vibrations are derived from multiple probes, mounted on one or more arms that rotate in the contaminated water tank.

[0021] Methods for the removal of small amounts of hormones and endocrine disruptors have already been described.

[0022] US 2007/0209999 describes a system for the treatment of waste water comprising a bioreactor, which comprises a bacterial population and an adsorbent, particularly active carbon in powder form. The examples in this application illustrate the removal of endocrine disruptors.

[0023] EP 1857541 B1 describes estrogenic compound degrading microorganisms and a method for breaking down these estrogenic compounds in domestic waste water and waste water from livestock farms

[0024] The removal of estrogenic substances from sewage water using cyclodextrin polymers is described by Kyoko Oishi and Ayumi Moriuchi in "Science of The Total Environment, Vol 409 Part 1 of 1 December 2010, Pag. 112-115"

[0025] WO 2008/039360 describes a method for the destruction of pharmaceuticals and personal care products, such as estrogenic compounds, antibiotics, and other aqueous solutions using ultrasonic vibrations.

[0026] US 7491339 describes a method for the destruction of harmful substances in water by irradiation with ultraviolet light, in which photocatalysis with titanium dioxide is used. It was shown that this method efficiently destroys β-estradiol, present in low concentrations in drinking water and domestic water.

[0027] The characterisation of MIP (molecularly imprinted polymer) and NIP

(non-imprinted polymer), submicron particles developed for the removal of 173-estradiol from water is described by PC Edward Lai, Zackery The Maleki and Shuyi Wu in "Journal of Applied Polymer Science, Volume 116, Part 3, 5 May 2010, pag. 1499-1508 ".

[0028] A method and a device for the removal of organotin components, such as tributyltin from a water/sediment mixture are described in DE 19 952 558. Via this method, the mixture is warmed to a temperature of 240°C under increased pressure, using a steam treatment. The method leads to the destruction of organotin components. Object of the invention.

[0029] The various methods already described exhibit a number of limitations or drawbacks with respect to purification capacity, economic aspects, upscaling, and the regeneration of the applied materials and the resulting waste.

[0030] The main object of this invention is to provide a method, which is not subject to the limitations or disadvantages of the already existing methods.

[0031] The object of this invention is to provide an economically attractive method for the removal of organic contaminants from water, which is characterised by a high purification capacity, wherein several impurities may be removed at the same time and the material employed in this method may be regenerated in an efficient manner. Main characteristics of the invention.

[0032] The invention involves a method as described in the appended claims.

[0033] The invention brings a novel method to light for the removal of organic impurities from water, in which organic impurities refer to hydrocarbons, mineral oils, organometals, and products which have a steroid skeleton or a steroid-derived skeleton.

[0034] The method is based on bringing the contaminated water into contact with a thermoplastic elastomer, preferably a block copolymer, which contains styrene-based hard sequences, wherein the thermoplastic elastomer, while it is in contact with the contaminated water, is subjected to a mechanical force and/or a force field. The application of the force and/or force field results in an improvement regarding the removal of the contaminant from the water and its storage in the elastomer, when compared to a treatment during which no force (field) is applied. The force field is preferably an ultrasonic force field. The mechanical force may be such that particles of the elastomer are compressed or otherwise elastically or plastically deformed. According to the invention, the force and/or force field are actively applied to the mixture of contaminated water and elastomer, i.e. the force and/or force field and thereby the level of the energy input into the mixture of water and elastomer is actively controlled. For this reason, the force and/or force field are preferably applied when the elastomer and the contaminated water are present in a container. According to a preferred embodiment, the thermoplastic elastomer is applied in the form of particles. The particle size is preferably between 0.1 mm and 2 mm. According to another embodiment, the thermoplastic elastomer is first treated according to the process of electrospinning which produces a woven polymer mat, consisting of microscopic polymer fibers, i.e. nanofibers. The term 'nanofibers' may be read in the present context as 'fibers obtainable by the electrospinning technique'. According to this embodiment, contaminated water is pumped through one or more of these polymer mats, thereby exhibiting a force on the elastomer fibers which enhances the removal of organic contaminants in accordance with the invention. The polymer mat thereby produces an additional filtration effect on floating contaminant particles in the water.

[0035] In an additional step, the thermoplastic elastomer, which contains the contaminants, may be stripped of these impurities, for example, via an extraction process, by a steam treatment, or by treatment with hot air, after which the purified thermoplastic elastomer may be reused in the water purification process. Detailed description of the invention.

[0036] The present invention involves a method for the removal of organic contaminants from water, wherein a thermoplastic elastomer is brought into contact with the contaminated water.

[0037] In the context of this invention, contaminated water preferably means contaminated surface water, drinking water, domestic and industrial waste water, and effluents and/or influents from water treatment plants, in which the concentration of organic contamination is 50 g/l or less, more preferably 10 g/l or less, more preferably 1 g/l or less, more preferably 500 mg/l or less, more preferably 100 mg/l or less, more preferably 1 mg/l or less, more preferably 500 g/l or less, more preferably 100 g/l or less, more preferably 1 pg/l or less, more preferably 500 ng/l or less, more preferably 100 ng/l, more preferably 10 ng/l or less, or even 1 ng/l or less.

[0038] The concentration of organic contamination is preferably at least 1 pg/l, more preferably at least 10 pg/l, more preferably at least 100 pg/l, more preferably at least 1 ng/l, more preferably at least 10 ng/l, more preferably at least 100 ng/l, more preferably at least 1 g/l, more preferably at least 10 pg/l, more preferably at least 100 pg/l, more preferably at least 1 mg/l, more preferably at least 10 mg/l, more preferably at least 100 mg/l, more preferably at least 1 g/l, more preferably at least 10 g/l.

[0039] In the present invention, organic contaminants refer to hydrocarbons, mineral oils, organometallic compounds, and natural or synthetic substances, which comprise a steroidal skeleton or derivative of a steroidal skeleton.

[0040] In the present invention, mineral oil refers to paraffin oils, naphthenic oils, and aromatic oils, containing C10-C60, preferably C10-C40 n-alkanes, cycloalkanes, and aromatic alkanes.

[0041] Specific examples of mineral oils, which may be isolated from contaminated water by using this invention, may be found as crude oil, fuel, such as used for ship engines, kerosene, gasoline, fuel oil, gas oil, hydraulic oil, lubricant and coolant.

[0042] In this invention, hydrocarbons refers to C1-C60, preferably C4-C50, and more preferably C6-C40 saturated and unsaturated aliphatic hydrocarbons and aromatic hydrocarbons that may comprise one or more oxygen, nitrogen, sulphur, phosphorus atom(s) and/or ketone, aldehyde, ester amide function(s) in the hydrocarbon skeleton and/or may comprise one or more halogen-, sulphur-, oxygen-, phosphorus-, and nitrogen-containing substituents.

[0043] Specific examples of hydrocarbons, which can be isolated from contaminated water using the invention, are benzene, toluene, ethylbenzene, xylene, naphthalene, anthracene, phenols, nitrophenols, and halogenated benzenoid structures, which include insecticides and pesticides.

[0044] The method of the present invention is preferably applicable for the removal of aromatic compounds such as benzene, toluene, ethyl benzene and xylene, and aliphatic compounds such as hexane, decane, and their isomers, from contaminated water.

[0045] In this invention, organometallic compounds refer to organoaluminium compounds such as diethylaluminium chloride, diisobutylaluminium hydride, ethylaluminium sesquichloride, triethylaluminium and trimethylaluminium; organogermanium compounds such as germanabenzene and tetraethylgermanium; organomercury compounds such as diphenylmercury, dimethylmercury, ethylmercury, phenylmercuric acetate, phenylmercuric nitrate, merbromin, methylmercury, and thiomersal; organolithium compounds such as n- butyllithium, s-butyllithium, tertbutyllithium, phenyllithium, n-hexyllithium, methyllithium, and propynyllithium; organolead compounds such as tetraethyl lead and tetramethyl lead; organomagnesium compounds such as allylmagnesium bromide, dimethylmagnesium, phenylmagnesium bromide; organopalladium compounds, such as tris(dibenzylideneacetone)dipalladium(0); organotin compounds such as azocyclotin, dibutyl tin oxide, stannabenzene, tributyl tin chloride, and tributyl tin hydride; organozinc compounds such as dimethylzinc.

[0046] A specific example of an organometallic compound, which may be isolated from contaminated water by using this invention, is tributyl tin hydroxide, tributyl tin chloride, and tributyl tin oxide.

[0047] In the present invention, natural or synthetic substances which contain a steroid skeleton or a skeleton derived therefrom refer to substances which have a

2,3,4,5,6,7,8,9,10,1 1 ,12,13,14,15,16, 17-hexadecahydro-1 H-cyclopenta[a]phenanthrene skeleton or a skeleton derived therefrom, wherein said skeleton :

• may comprise one or more unsaturated double bonds,

• may comprise one or more methyl, hydroxy I, aldehyde, amine, amide (-NH- CO-R), or oxygen (= O to form a ketone function, or -O- to form an oxirane structure) substituents,

• specifically comprises substituents in position 17, selected from the group consisting of hydrogen, hydroxyl, oxygen, a hydrocarbon substituent comprising 1 to 10 carbon atoms, which may contain one or more unsaturated bonds and/or 1 or more heteroatoms, and which may form a bond with position 16 and an aromatic substituent, comprising 1 to 10 carbon atoms and which may contain one or more heteroatoms and/or substituents.

[0048] The steroid substances, in the context of the present invention, include the group consisting of secosteroids, norsteroids and homosteroids, and include natural or synthetic hormones, such as glucocorticoids, mineralocorticoids, androgens, oestrogens, progestogens, and vitamin D.

[0049] The natural or synthetic substances specifically referred to in this invention, which contain a steroid skeleton or a skeleton therefrom, preferably comprise a 2,3,4,5,6,7,8,9,10,1 1 , 12,13,14,15,16, 17-hexadecahydro-1 H-cyclopenta[a]~ phenantrene skeleton which has one or more unsaturated double bonds, one or more methyl substituents, one or more hydroxyl groups, and which comprises substituents in position 17, selected from the group consisting of hydrogen, hydroxyl, oxygen (0=, to form a ketone function), a C1-C10 hydrocarbon substituent, a C1-C10 unsaturated hydrocarbon substituent, which contains 1 or more double and/or triple bonds, and a heteroaromatic substance.

[0050] Specific examples are modified steroids, such as cholesterol, for example, present in cosmetics and personal care products, abiraterone, an anti-androgen, and endocrine disrupting substances, like oestrogens such as estriol, estradiol, oestrone, and ethinyl estradiol.

[0051] According to one embodiment, the thermoplastic elastomer used in this invention is a block copolymer, preferably a triblock copolymer consisting of hard and soft sequences, wherein the hard sequences are obtained by polymerisation of monovinylarene and wherein the soft sequences are obtained by polymerisation of alkylenes or by copolymerisation of alkylenes and monovinylarene.

[0052] In the event that the alkylene is a conjugated diene, an unsaturated thermoplastic elastomer is obtained; in the event that the alkylene is a monoalkene, a saturated thermoplastic elastomer is obtained.

[0053] The monovinylarene is preferably selected from the group consisting of styrene, omethyl styrene, and vinyl toluene. The monovinylarene is preferably styrene.

[0054] The alkylene is preferably selected from the group consisting of ethylene, propylene, butylene, isobutylene, pentene, hexene, octene, butadiene, isoprene, 2,3-dimethyl-1 ,3-butadiene, piperylene, 3-butyl-1 ,3 -octadieen, and phenyl-1 ,3-butadiene. The alkylene is preferably butadiene, isoprene, for the formation of an unsaturated thermoplastic elastomer; or ethylene, propylene, or butylene for the formation of a saturated thermoplastic elastomer.

[0055] The block copolymers, to be used in the method according to the present invention, are preferably selected from the group consisting of styrene-butadiene- styrene, styrene-isoprene-styrene, styrene-isobutylene-styrene, styrene-ethylene-butylene- styrene, styrene -ethylene-propylene-styrene, styrene-ethylene-ethylene-propylene-styrene.

[0056] The thermoplastic elastomers preferably used in the method of this invention are prepared as described in, for example, WO 1995/35335 or WO 1997/40079, and may be prepared by anionic polymerisation in a non-polar solvent with the addition of a polar cosolvent or a potassium salt.

[0057] The thermoplastic elastomer of this invention preferably contains between 10 and 60 percent by weight of hard sequences, more preferably between 15 and 50 percent by weight of hard sequences, and even more preferably between 20 and 40 percent by weight of hard sequences.

[0058] The thermoplastic elastomers preferably used in the method of this invention are characterised by a melt index (melt flow rate) (ASTM D1238, 200°C / 5 kg) of between 2 and 50 g/10 min, preferably between 5 and 20 g/10 min.

[0059] The thermoplastic elastomers preferably used in the method of this invention are block copolymers in which the soft sequence have a molecular weight between 2,000 and 250,000 g/mol and a glass transition temperature, as determined by differential scanning calorimetry, of 25°C or lower and in which the hard sequence has a molecular weight of between 1 ,000 and 200,000 g/mol and a glass transition temperature above 25°C.

[0060] The soft sequences preferably have a glass transition temperature, as determined by differential scanning calorimetry, of between 25 and -1 10°C, preferably between 5 and -100°C, and more preferably between -10 and -90°C or even between -20 and -90°C.

[0061] It is obvious that the thermoplastic elastomers used in the method of this invention may include other components and/or additives such as thermoplastic homopolymers and/or copolymers, thermosetting polymers, fillers, wetting agents, surfactants, foaming agents, anti-foaming agents, pigments, dyes, anti-static agents, stabilisers, antioxidants, flame retardants, and flow enhancers.

[0062] Without being bound to any theory, it is stated that the polymer chains of the thermoplastic elastomers are physically cross-linked by association of the hard polyvinylarene sequences, wherein the organic contamination is absorbed into the soft sequences.

[0063] The glass transition temperature of the soft sequences must be sufficiently low so that, during the purification process, these soft sequences are mobile enough to absorb and/or adsorb the contaminants. On the other hand, the glass transition temperature of the hard sequences should be high enough to ensure that the thermoplastic elastomers do not cake during the purification process.

[0064] The density of the thermoplastic elastomer to be used in the method of this invention is preferably between 0.5 and 1 .5 g/cm³ and more preferably between 0.8 and 1 .3 g/cm³.

[0065] The thermoplastic elastomer is preferably used in granular, tubular, or powder form, but may, in principle, have any physical form. [0066] In the method of the present invention, the contaminated water is brought into contact with the thermoplastic elastomer: either stationary, during which a certain amount of elastomer is added to a certain amount of contaminated water, or non-stationary, during which water is pumped, at a given flow rate, through the thermoplastic elastomer. In both cases, either stationary or non-stationary, the thermoplastic elastomer in contact with the contaminated water is subjected to a force field or to a mechanical force. Preferably, during the stationary as well as the non-stationary method, the elastomer remains in a container during the contact with the contaminated water. First the application of a force field will now be described, with reference to the preferred embodiment, according to which an ultrasonic force field is applied.

[0067] To this end, for example, one or more containers are provided with one or more ultrasonic probes and/or transducers connected to one or more ultrasonic generators with a nominal power of between 100 and 10,000 W, preferably between 200 and 2,000 W, which produce waves with frequencies in the range from 10 kHz to 1 MHz, preferably from 15 kHz to 500 kHz, more preferably from 20 kHz to 200 kHz. The ultrasonic probe(s) may optionally be provided in combination with one or more reflectors.

[0068] In order to obtain maximum efficiency of the ultrasonic treatment, it is important that the ultrasonic force field is applied over as large an area as possible of the thermoplastic elastomer in contact with contaminated water. Preferably, the ultrasonic wave field is applied to the entire portion of thermoplastic elastomer which is in contact with the contaminated water.

[0069] In an embodiment of the stationary method, one or more containers are used, each provided with at least one opening for filling and/or emptying the container and with one or more ultrasonic probes and/or transducers. The containers may be filled with contaminated water and be emptied of pure water separately and independently of each other.

[0070] Between 10^"7 and 100 g, preferably between 10^"5 and 80 g, more preferably between 10^"3 and 60 g, or even between 10^"1 and 50 g of the thermoplastic elastomer is added to the one or more containers per 100 g of contaminated water, depending on the degree of pollution and the type of contaminant, wherein the thermoplastic elastomer in contact with the contaminated water is subjected to ultrasonic vibration energy for a period of between 1 second and 24 hours, preferably between 10 seconds and 10 hours, depending on the degree of pollution and the type of contaminant, wherein the ultrasonic force field is applied continuously or with one or more interruptions. The thermoplastic elastomer in contact with the contaminated water may be stirred continuously or intermittently during the entire period of contact. [0071] Then, the ultrasonic force field is switched off and purified water is separated from the thermoplastic elastomer, for example by filtration.

[0072] Contaminated water may be added to the thermoplastic elastomer again, followed by ultrasonic treatment, and separation of pure water. The sequences of filling, purification, and separation may be repeated until a decrease in the purifying capability of the thermoplastic elastomer is observed.

[0073] In an embodiment of the non-stationary method, one or more containers is used, each provided with at least one opening for filling and/or emptying the container, and one or more ultrasonic probes and/or transducers, and wherein one or more containers are partially or completely filled with thermoplastic elastomer. Each of the containers is configured to be placed in a circuit, wherein liquid flows through the container. This can happen through the openings for filling and emptying or via specifically-prepared flow openings. Devices are provided (e.g., sieves or the like) in order to ensure that the thermoplastic elastomer in the containers remains in place, while the polluted water flows through the circuit. For the case of multiple containers, these are connected in series and/or parallel.

[0074] In the non-stationary method, the contaminated water is pumped through the thermoplastic elastomer, which is located in one or more containers. The water is pumped, for example, in an upward direction, wherein the flow rate of the water is between 10 and 100,000 parts per hour, preferably between 20 and 75,000 parts per hour, more preferably between 30 and 50,000 parts per hour, or even between 50 and 20,000 parts per hour, depending on the degree of pollution and the type of contaminant, for one or more containers, which contain 100 parts of thermoplastic elastomer in total.

[0075] The force field is applied to the thermoplastic elastomer, while the contaminated water is pumped through the elastomer. The container(s) may be stirred during the treatment.

[0076] The one or more containers which are preferably employed in the stationary and non-stationary embodiment of this invention, are preferably cylindrical in shape and equipped, at one or several levels, preferably along the longitudinal axis of the container(s), with one or more probe(s), preferably in circular formation, whereby the probe(s) may individually be switched on and off depending for example on the degree of fullness of the container(s) with thermoplastic elastomer. The number of probes and/or transducers, which are part of the preferably circular formation, is 1 , or more preferably 2, 3, 4, 5, or 6.

[0077] Fig. 1 shows a possible embodiment of a container 1 , through which the contaminated water may be pumped via inlet 2 to the outlet 3, while elastomer particles are kept in the container by nets or sieves 4. Ultrasonic probes and/or transducers 5 are arranged on three levels, each in circular formation around the container 1 . One level has been shown in cross-section, in which three probes and/or transducers 5 are arranged around the circumference. On the other levels, at least two probes are placed.

[0078] Optionally, the containers may be equipped with a stirring system in order to bring about optimum contact between the thermoplastic elastomer and the contaminated water and a homogeneous distribution of the thermoplastic elastomer in contact with the contaminated water, throughout the ultrasonic force field.

[0079] The contaminated water is preferably at a temperature between 0 and

25°C, but may be heated if necessary. In the event that the contaminated water needs to be heated, the one or more containers are preferably adiabatic.

[0080] The purifying ability of the thermoplastic elastomer may be determined or example by checking the water which exits the container with thermoplastic elastomer, for any remaining contaminants by using ultra-high-performance liquid chromatography combined with mass spectrometry.

[0081] When a decrease in the purifying capability of the thermoplastic elastomer is observed, then the thermoplastic elastomer is regenerated.

[0082] The thermoplastic elastomer may be stripped of the absorbed impurities, for example, by a Soxhlet type extraction using a non-polar solvent such as (cyclo)hexane, isooctane, toluene, or xylene.

[0083] Alternatively, the thermoplastic elastomer may be stripped of the absorbed chemical impurities using steam, according to the principle of the steam distillation.

[0084] The thermoplastic elastomer may also be stripped of the absorbed chemical impurities by treating it with cold or hot air; this treatment is preferably applied in the case of volatile impurities.

[0085] The thermoplastic elastomer, stripped of the chemical impurities, is then dried, for example, at an elevated temperature, such as 50°C, and under reduced pressure or by blowing with heated air.

[0086] The dried thermoplastic elastomer may be re-used in a subsequent waste water treatment.

[0087] The method of the present invention makes it possible to decrease the concentration of organic contaminants by 50% or more, preferably 60% or more, more preferably 70% or more, more preferably 80% or more, more preferably 90% or more, more preferably 95% or more, more preferably 97% or more, more preferably 99% or more, more preferably 99.5% or more, or more preferably 99.9% or more, relative to the initial concentration.

[0088] The method of this invention makes it possible to obtain purified water with a concentration of residual organic contamination of 10 g/l or less, preferably of1 g/l or less, more preferably 500 mg/l or less, more preferably 100 mg/l or less, more preferably 1 mg/l or less, more preferably 500 g/l or less, more preferably 100 g/l or less, more preferably 1 g/l or less, more preferably 500 ng/l or less, more preferably 100 ng/l or less, more preferably 10 ng/l or less, more preferably 1 ng/l or less, more preferably 500 pg/l or less, more preferably 100 pg/l or less, more preferably 10 pg/l or less, or more preferably 1 pg/l or less.

[0089] As mentioned, instead of or together with a force field, a mechanical force may also be applied to the elastomer while it is in contact with the contaminated water. In practice, this means that particles of the elastomer are brought into physical contact with a moving body, so that they are deformed elastically or plastically. Preferably, the order of magnitude of the forces is similar to that exerted by the ultrasonic force field described above. In other words, the power must work in such a way on the particles that the purifying action of the elastomers is enhanced, for example by increasing the mobility of the soft polymer sequences.

[0090] Fig. 2 illustrates a first possible embodiment of a method and device according to the invention, in which the elastomer is subject to a mechanical force. In a cylindrical container 10 comprising elastomer particles a cylindrical roller is rotatably installed. The roller has a diameter, which is smaller than the diameter of the container and is eccentrically placed with respect to the symmetry axis 12 of the container, so that a narrow passageway 13 is formed between the outer wall of the roller 1 1 and the inner wall of the container 10. The drawing is not to scale in order to make the passage 13 clearly visible, but this is, in reality, smaller compared to the dimensions of the container 10 and the roller 1 1. The width of the passage 13 is of the same order of magnitude as a defining dimension of the elastomer particles. Preferably, the particles are spherical and the diameter of the particles is the defining dimension. The roller may rotate about its axis of symmetry 14. The speed of rotation is selected such that the particles are continuously carried by a current through the passage 13, so that they are lightly compressed by the action of the passage itself, in combination with the pressure of the water. This container may be used in a stationary or non-stationary method, as described in connection with the ultrasonic treatment. The values listed above, for certain parameters in the ultrasonic embodiment, such as the content of the elastomer, the flow rate, the treatment time and the like, are also applicable for the embodiment of Fig. 2.

[0091] Fig. 3 shows a second embodiment in which a mechanical force is exerted on the elastomer particles. The particles 15 are contained in the cylinder 21 of a piston pump 20, comprising a piston 22, a suction pipe 23 with suction valve 24, and a pressure conduit 25 with discharge valve 26, wherein means are provided near the suction and/or delivery valve (e.g. sieves or something similar) for maintaining the thermoplastic elastomer in the cylinder 21 of the piston pump 20 during the suction of the contaminated water through the suction pipe 22 into the cylinder 20 and during the compression and removal of the purified water via pressure pipe 24 from the cylinder. Suction and compression is accomplished via the outward (suction stroke) and inward (pressure stroke) movement of the piston 22, wherein the elastomer particles are compressed during the inward movement which increases their purification capacity.

[0092] The piston pump may be used in a stationary or non-stationary method.

[0093] In the stationary method, the piston pump, which contains the thermoplastic elastomer particles, is placed in a container with contaminated water, wherein the water is drawn a number of times into the cylinder and extracted from the cylinder until the desired reduction of contaminants is observed.

[0094] In the non-stationary method, the purified water flows through the cylinder of one or several piston pumps, which, in the case of multiple piston pumps, are arranged in series and/or in parallel and optionally equipped with buffer tanks.

[0095] Without being bound to any theory, it is stated that the application of a force field and/or a mechanical force improves the purifying function of the elastomer as a result of an increase in, among other things:

the mobility of the soft polymer sequences,

the diffusion of the organic contaminants to the thermoplastic elastomer,

- the transport of the organic contaminants from the aqueous layer that is in direct contact with the thermoplastic elastomer, to the thermoplastic elastomer,

the renewal of the water layer in direct contact with the thermoplastic elastomer, all of which are favourable for the absorption of the organic contaminants by the thermoplastic elastomer.

In a specific embodiment of the non-stationary method, the thermoplastic elastomer is placed in a container in the form of one or more mats formed of microscopic fibers of the elastomer, i.e. mats formed of nanofibers of the elastomer. These mats are obtainable by the electrospinning technique, known as such in the art. In the document ' Use of Triazolinedione Click Chemistry for Tuning the Mechanical Properties of Electrospun SBS- Fibers', van de Heyden et al, pubs.acs.org/macromolecules, publication date (web) 3 September 2015, an electrospinnig procedure is described applied to styrene-butadiene- styrene (SBS), which is applicable for obtaining a polymer microfibrous mat that can be used in the invention. According to the method of the invention, this mat or several mats are placed in a container and contaminated water is pumped through the mats at a suitable flow rate so as to establish contact between the water and the mats. The flow itself as generated by the pumping action generates a force being exerted on the elastomeric fibers, in accordance with the general inventive concept. This force enhances the purifying action of the elastomer as described above, for example by increasing the mobility of the soft polymer sequences. An additional advantage of this embodiment is that the polymer mats effectuate a filtration of the contaminated water by the fact that they capture contaminants in the form of floating microscopic particles, other than organic contaminants, from the water. In this way, the filtration technique is capable of resulting in a more thorough purification.

[0096] For each of the methods described above, both the stationary and non- stationary methods, salt may be added to the contaminated water to decrease the solubility of certain impurities in the water and to increase the absorption capacity of impurities in the thermoplastic elastomer.

[0097] For this purpose, for example, sodium chloride may be added to the contaminated water in order to obtain a concentration between 100 and 350 g of salt per litre of water.

[0098] For each of the methods described above, both the stationary and non-stationary methods, regulation of the acidity of the contaminated water may be necessary. This regulation has its primary application when the organic impurities are present in the form of salts, wherein an adjustment of the pH makes the organic contamination easier to become absorbed in the thermoplastic elastomer. Depending on the type of contaminant, the regulation of the degree of acidity may involve an increase or a reduction of the pH of up to 13 units, preferably up to 10 units.

[0099] For example, in the case of contaminated water containing mercaptan salts, the acidity should be reduced in order to obtain better purification capacity for the thermoplastic elastomer.

[0100] The present invention also involves a method for the removal of organic contaminants from sludge, during which a thermoplastic elastomer is brought into contact with the sludge, and an ultrasonic force field is applied.

[0101] In the present invention, sludge refers to a mixture of earth, water, and contaminants, wherein the term "earth" means gravel, clay, loam, loess, silt, peat, sand, and combinations thereof, such as sabulous clay, and wherein the concentration of earth is 900 g/l or less, more preferably 800 g/l or less, more preferably 700 g/l or less, more preferably 600 g/l or less, more preferably 500 g/l or less, more preferably 400 g/l or less, more preferably 300 g/l or less, more preferably 200 g/l or less, more preferably 100 g/l or less, or more preferably 50 g/l or less, and wherein the concentration of organic contamination is 50 g/l or less, preferably 10 g/l or less, more preferably 1 g/l or less, more preferably 500 mg/l or less, more preferably 100 mg/l or less, more preferably 1 mg/l or less, more preferably 500 μg/l or less, more preferably 100 g/l or less, more preferably 1 g/l or less, more preferably 500 ng/l or less, more preferably 100 ng/l or less, more preferably 10 ng/l or less, or even 1 ng/l or less. [0102] The concentration of organic contamination is preferably at least 1 pg/l, more preferably at least 10 pg/l, more preferably at least 100 pg/l, more preferably at least 1 ng/l, more preferably at least 10 ng/l, more preferably at least 100 ng/l, more preferably at least 1 pg/l, more preferably at least 10 pg/l, more preferably at least 100 pg/l, more preferably at least 1 mg/l, more preferably at least 10 mg/l, more preferably at least 100 mg/l, more preferably at least 1 g/l, more preferably at least 10 g/l.

[0103] The purification of sludge may occur by way of a stationary or non-stationary embodiment, analogous to those employed for the purification of contaminated water, through which purified sludge is obtained with a concentration of residual organic contamination of 10 g/l or less, preferably from 1 g/l or less, more preferably 500 mg/l or less, more preferably 100 mg/l or less, more preferably 1 mg/l or less, more preferably 500 pg/l or less, more preferably 100 pg/l or less, more preferably 1 pg/l or less, more preferably 500 ng/l or less, more preferably 100 ng/l or less, more preferably 10 ng/l or less, more preferably 1 ng/l or less, more preferably 500 pg/l or less, more preferably 100 pg/l or less, more preferably 10 pg/l or less, or more preferably 1 pg/l or less.

[0104] The thermoplastic elastomer, which contains the impurities of the sludge, is regenerated by means of a Soxhiet type extraction, by a treatment with steam, or by treatment with warm air and is reused after drying. Examples

[0105] The examples below are intended to illustrate the invention and in no way imply a limitation of the invention.

Example 1 : Synthesis of a thermoplastic elastomer based on styrene and butadiene.

[0106] A styrene - butadiene/styrene - styrene triblock copolymer was prepared according to a process as described in WO 1997/40079.

[0107] A 50 litre reactor was loaded with 22.8 litres of dry cyclohexane and

1638 grams of dry styrene and heated to 40°C, wherein polymerisation was initiated by the addition of 87.3 mmol of sec-butyllithium (12 percent by weight in dry cyclohexane) and 2.36 mmol of potassium tert-amylate (5 percent by weight in dry cyclohexane). The reaction mixture was stirred for 30 minutes, during which a temperature of 68°C was maintained.

[0108] The reaction mixture was then cooled to 50°C and 1 126 grams of butadiene and 1250 grams of styrene were added simultaneously. The temperature rose to 74°C. After a polymerisation time of 13 minutes, the obtained reaction mixture was cooled to 55°C and a second portion, consisting of 1 126 grams of butadiene and 1250 grams of styrene, was added. The temperature rose to 76°C. After a polymerisation time of 13 minutes, the mixture was cooled to 55°C and a third portion consisting of 1 126 grams of butadiene and 1250 grams of styrene was added, during which the temperature rose to 75°C. After 17 minutes, 1638 grams of styrene were added at a temperature of 70°C, during which the temperature rose to 80°C.

[0109] 40 minutes after the addition of styrene, the polymerisation was terminated by adding 200 mmol of isopropanol, acidified by the addition of carbon dioxide and water, and stabilised by the addition of 35 grams of Irganox^® 3052 and 80 g of Weston^® TNPP. Then, the polymer was stripped of solvent and transformed into granular form using an extruder.

[0110] The thermoplastic elastomer was characterised by an average molecular weight of 140,000 g/mol, and 2 glass transition temperatures, of which the first glass transition temperature was between -25 and -55°C and the second glass transition temperature was between 60 and 100°C.

[0111] The thermoplastic elastomer contains 31 .5 percent by weight of polystyrene block.

Example 2: Synthesis of a thermoplastic elastomer based on styrene and isoprene.

[0112] A styrene - isoprene/styrene - styrene triblock copolymer was prepared according to the same method as the styrene - isoprene/styrene - styrene triblock copolymer of Example 1 , the difference being that each time 1420 g of isoprene and 1250 grams of styrene are added in the three subsequent steps.

[0113] Reaction temperatures and reaction times are those of Example 1. The other reagents and solvents from Example 1 , as well as their respective quantities, were added.

[0114] The thermoplastic elastomer was characterised by an average molecular weight of 135,000 g/mol, and 2 glass transition temperatures, of which the first glass transition temperature was between -30 and -60°C and the second glass transition temperature was between 60 and 100°C.

[0115] The thermoplastic elastomer contains 29 percent by weight of polystyrene block. Example 3: Purification of industrial waste water sample, which contains mineral oils and other hydrocarbons.

[0116] An industrial water sample was collected upon outflow and analysed for

C10-C40 alkanes and aromatic hydrocarbons.

[0117] 50 g of the thermoplastic elastomer from Example 1 was added to a container of 500 g of contaminated water at room temperature, all of which was subjected for 30 minutes to an ultrasonic force field produced by an ultrasonic laboratory probe UP50H (Hielscher Ultrasonics GmbH), in contact with the water surface. The 'contaminated water - thermoplastic elastomer' mixture was stirred during ultrasonic treatment, using a magnetic stirrer. The thermoplastic elastomer was then filtered out and the purified water was analysed.

[0118] In Table 1 , the concentration of C10-C40 alkanes and aromatic hydrocarbons, in nanograms per millilitre, is shown before and after purification.

Table 1

[0119] Table 1 shows that the application of a thermoplastic elastomer in conjunction with an ultrasonic force field decreases the concentration of chemical contaminants, which consist of mineral oil and other hydrocarbons, to a value between 30 and less than 10% of the original value.

Example 4: Purification of an industrial waste water sample containing abiraterone.

[0120] An industrial water sample was collected upon outflow and analysed for

(33)-17-(pyridin-3-yl)androsta-5,16-dien-3-ol (= abiraterone)

[0121] 10 g of the thermoplastic elastomer from example 1 was added to a container of 40 g of contaminated water at room temperature, all of which was subjected, for 0, 10, and 30 minutes respectively, to an ultrasonic force field produced by an ultrasonic laboratory probe UP50H (Hielscher Ultrasonics GmbH), in contact with the water surface. The 'contaminated water - thermoplastic elastomer' mixture was stirred during ultrasonic treatment, using a magnetic stirrer. The thermoplastic elastomer was then filtered out and the purified water was analysed.

[0122] In Table 2, the concentration, in nanograms per millilitre, of abiraterone, before and after purification is shown. Sample Abiraterone

concentration

1 contaminated water 99.4

2 contaminated water + 23.8

thermoplastic elastomer

3 contaminated water + 4.2

thermoplastic elastomer + ultrasound (10 minutes)

4 contaminated water + 1 .9

thermoplastic elastomer + ultrasound (30 minutes)

Table 2

[0123] Table 2 clearly shows the effect of the ultrasonic force field (sample 3 and 4 versus sample 2) on the purifying capacity of the thermoplastic elastomer. The use of only thermoplastic elastomer will reduce the concentration of abiraterone by 25% or less of its original value; with the application of ultrasonic waves the abiraterone concentration decreased to 5% or less of its original value.

Example 5: Purification of industrial waste water sample that contains 17oestradiol, 17β- estradiol, oestrone, and ethinyl estradiol.

[0124] An industrial water sample (sample 1 ) was collected upon outflow and analysed for 17oestradiol, 173-estradiol, oestrone, and ethinyl estradiol.

100 g of the thermoplastic elastomer from example 2 was added to a container with 200 g of contaminated water, all of which was kept at 40°C for 6 hours. The thermoplastic elastomer was then filtered out and the purified water (sample 2) was analysed.

[0125] Afterwards, 100 g of the thermoplastic elastomer from example 1 was added to a container of 200 g of contaminated water at room temperature, all of which was subjected for 30 minutes to an ultrasonic force field produced by an ultrasonic laboratory probe UP50H (Hielscher Ultrasonics GmbH), in contact with the water surface (sample 3).

[0126] Table 3 shows the concentrations in nanograms per millilitre of

17a-estradiol, 173-estradiol, oestrone, and ethinyl estradiol for the various water samples (samples 1 , 2 and 3)

Table 3 [0127] Table 3 shows the effect of the thermoplastic elastomer in terms of the decrease of impurities (sample 2); a decrease to 20% and less of the initial values is obtained. Application of an ultrasonic force field results in a further decrease to less than 2% of the initial value.

Claims

1. A method for removing organic contaminants from water comprising the steps of :

- bringing water that contains organic contaminants into contact with a thermoplastic elastomer and applying a force field and/or a mechanical force to the thermoplastic elastomer while it is in contact with the water;

separating the water, with a reduced concentration of organic contaminants, from the thermoplastic elastomer.

2. The method according to claim 1 , wherein the organic contaminants comprise a hydrocarbon or a mixture of hydrocarbons, and wherein said hydrocarbon or hydrocarbons belong to the group consisting of d-Ceo n-alkanes, cycloalkanes, and aromatic alkanes, preferably to the group consisting of C4-C50 n-alkanes, cycloalkanes, and aromatic alkanes; and more preferably to the group consisting of C6-C 0 n-alkanes, cycloalkanes, and aromatic alkanes.

3. The method according to claim 1 or 2, wherein the organic contaminants comprise mineral oil.

4. The method according to any one of claims 1 to 3, wherein the organic contaminants comprise an organometaiiic compound selected from the group consisting of organoaluminium, organogermanium, organomercury, organolithium, organolead, organomagnesium, organopalladium, organotin, and organozinc.

5. The method according to any one of claims 1 to 4 in which the organic contaminants comprise a 2,3,4,5,6,7,8,9,10,1 1 ,12,13,14,15,16,17-hexadecahydro-1 H- cyclopenta[a]phenanthrene skeleton or a skeleton derived therefrom that:

may comprise one or more unsaturated double bonds,

may comprise one or more methyl, hydroxy I, aldehyde, amine, amide (-NH-CO- R), or oxygen substituents, and

in position 17, comprises substituents selected from the group consisting of hydrogen, hydroxy I, oxygen, a hydrocarbon substituent and an aromatic substituent, wherein :

the hydrocarbon substituent

comprises between 1 and 10 carbon atoms, may comprise one or more unsaturated double and/or triple bonds,

may comprise one or more heteroatoms, and

may form a bond with position 16;

the aromatic substituent

comprises between 1 and 10 carbon atoms,

may comprise one or more substituents, and

may comprise one or more heteroatoms.

6. The method according to any of claims 1 to 5, wherein the organic contaminants comprise a natural or synthetic hormone or hormone analogue.

7. The method according to any of claims 1 to 6, wherein the organic contaminants comprise an endocrine disruptor.

8. The method according to any of claims 1 to 7, wherein the thermoplastic elastomer is a hydrocarbon that is free of heteroatoms.

9. The method according to any one of the preceding claims, wherein the force and/or force field are applied when the elastomer and the contaminated water are present in a container.

10. The method according to any of claims 1 to 9, wherein the thermoplastic elastomer comprises a block copolymer containing hard sequences obtained by polymerisation of monovinylarenes and soft sequences obtained by polymerisation of alkylenes, or by copolymerisation of monovinylarenes and alkylenes.

11. The method according to any of claims 1 to 9, wherein the thermoplastic elastomer comprises a block copolymer selected from the group consisting of styrene- butadiene-styrene, styrene-isoprene-styrene, styrene-isobutylene-styrene, styrene-ethylene- butylene styrene, styrene-ethylene-propylene-styrene, styrene-ethylene-ethylene-propylene- styrene.

12. The method according to any of the preceding claims, wherein said force field is an ultrasonic force field, obtained by bringing the water into contact with ultrasonic waves, while the water is in contact with the elastomer.

13. The method according to claim 12, wherein the ultrasonic waves are characterised by a frequency between 10 kHz and 1 MHz, preferably between 15 kHz and 500 kHz, and more preferably between 20 kHz and 200 kHz.

14. The method according to any one of the preceding claims, wherein said mechanical force is exerted upon the elastomer by bringing particles of the elastomer into contact with one or more moving surfaces.

15. The method according to claim 14, wherein the particles together with the contaminated water are held in a cylindrical container (10), and wherein a rotating roller (1 1 ) is located in the container, eccentrically placed in the container, so that a passage (13) is produced between the outer wall of the roller and the inner wall of the container, and wherein the mechanical force is applied through the fact that the particles flow with the water through the passage (13).

16. The method according to any of claims 1 to 15, wherein the contaminated water is stationary and held in a container (1 , 10), along with particles of the elastomer.

17. The method according to any of claims 1 to 15, wherein the water is pumped through one or more containers, which are completely or partly filled with thermoplastic elastomer, and, if there are multiple containers, these are arranged in series and/or in parallel.

18. The method according to claim 17, wherein the thermoplastic elastomer is placed in a container in the form of one or more mats formed of nanofibers of the elastomer, and wherein the water is pumped through said mat or mats.

19. The method according to claim 14, wherein contaminated water is sucked into the cylinder (21 ) of one or more piston pump(s) (20) the cylinder containing elastomer particles, and wherein a mechanical force is exerted on these particles by compression of the piston (22) for removing the water from the cylinder.

20. The method according to any of claims 1 to 19, wherein the contaminated water comprises elements selected from the group consisting of gravel, clay, loam, loess, silt, peat, sand, and combinations thereof.

21. The method according to any of claims 1 to 20, wherein salt, acid, or base, or a combination of salt and base, or of salt and acid, are added to the contaminated water.

22. The method according to any of claims 1 to 21 , wherein the concentration of organic contaminants decreases by 50% or more, preferably 60% or more, more preferably by 70% or more, more preferably by 80% or more, more preferably by 90% or more, more preferably by 95% or more, more preferably by 97% or more, more preferably by 99% or more, more preferably by 99.5% or more, or more preferably by 99.9% or more relative to the initial concentration.

23. The method according to any one of claims 1 to 22, consisting of an additional step in which the contaminant-containing thermoplastic elastomer is separated and regenerated, preferably by means of an extraction process, or by treatment with steam or with hot or cold air.

24. Use of the method according to any of claims 1 to 23 for the purification of domestic water, industrial waste water, surface water, drinking water, or effluents and/or influents of water purification stations.

25. A device for removing organic contaminants from water according to the method of any one of claims 1 to 13, comprising one or more containers, each provided with at least one opening for filling and/or emptying the container, wherein the one or more containers comprise a thermoplastic elastomer, and wherein the one or more containers comprise one or more ultrasonic probes and/or transducers positioned such that the thermoplastic elastomer, in contact with water, is subject to an ultrasonic force field, wherein the one or more ultrasonic probes and/or transducers are connected to a plurality of ultrasonic generators which may be individually switched on and off.