BE1022422B1 - METHOD FOR REMOVING ORGANIC POLLUTANTS FROM WATER - Google Patents

Abstract

The invention describes a method for removing organic contaminants comprising a steroid backbone or backbone derived therefrom from water, whereby the contaminated water is contacted with a thermoplastic elastomer.

Description

METHOD FOR REMOVING ORGANIC POLLUTANTS FROM WATER.

Domain of the invention.

The invention relates to a method for removing organic contaminants, in particular steroids, from water.

State of the art.

The over-exploitation of natural resources and the widespread use of chemicals have led to the accumulation of contaminants in our environment. Air, soil and water pollution have received constant attention in recent decades because of their adverse effects on ecosystems and on human and animal health.

Various methods are known for treating contaminated water, including mechanical methods such as natural flotation, forced flotation, filtration, centrifugal gravitation separation; electromagnetic methods such as ultrasonic, electrolytic and separation methods based on electrophoresis; other physical or chemical methods such as those based on adsorption, absorption, ion exchange and coagulation as well as biological separation methods using micro-organisms.

During the last few years, various studies have demonstrated the presence of small amounts of hormones and endocrine disrupting substances, pharmaceuticals and products intended for personal care in surface waters, wastewater and drinking water.

The hormone disrupting substances, which mimic the feminising effects of the female (estrogen) sex hormones, are of great interest. Synthetic estrogens are primarily present in contraceptives and in hormonal replacement therapy preparations. Synthetic estrogens are more stable than natural estrogens, do not biodegrade naturally and therefore end up in the environment.

However, the traditional treatment methods for treating contaminated water often fall short in removing these recently observed contaminants and new methods are described in the technical and patent literature.

LIS 2007/0209999 describes a waste water treatment system that includes a bioreactor that includes a bacterial population and an adsorbent, in particular powdered activated carbon. The examples in this application illustrate the removal of endocrine disruptors.

EP 1857541 B1 describes estrogenic substance degrading microorganisms and a method for degrading these estrogenic substances in domestic wastewater and wastewater from livestock farms.

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, Volume 409, Volume 1, December 1, 2010, Pag. 112-115 ”WO 2008/039360 describes a method for destroying pharmaceuticals and products intended for personal care, such as estrogenic substances, antibiotics and other, in aqueous solutions using ultrasonic vibrations.

US 7,491,339 describes a method for the destruction of harmful substances in water by irradiation with ultra-violet light, using photocatalysis with titanium dioxide. This method has been shown to efficiently destroy β-estradiol, present in low concentrations in drinking water and domestic water.

The characterization of MIP (molecularly imprinted polymer) and NIP (nonimprinted polymer) submicron particles developed for removing 17β-estradiol from water is described by Edward P.C. Lai, Zackery De Maleki and Shuyi Wu in "Journal of Applied Polymer Science, Volume 116, volume 3, May 5, 2010, p. 1499-1508 '.

Object of the invention.

The various methods as already described exhibit a number of limitations or disadvantages with regard to economic aspects, scaling up, regeneration of the materials used and the resulting waste.

The main purpose of this invention is to provide a method that is not subject to the limitations or disadvantages of the existing methods.

The object of this invention is to provide an economically attractive method for removing specific organic contaminants from water whereby different contaminants can be removed at the same time and wherein the material employed in this method can be regenerated in an efficient manner.

Main features of the invention.

The invention relates to a method as described in the appended claims.

The invention uncovers a new method for removing organic contaminants, which comprise a steroid skeleton or skeleton derived therefrom, from water.

The method is based on contacting the contaminated water with a thermoplastic elastomer, preferably a block copolymer that preferably contains styrene-based hard sequences, whereby the contamination is withdrawn from the water and stored in the elastomer. In an additional subsequent step, the thermoplastic elastomer containing the contaminants can be stripped of these contaminants and used again.

The organic contaminant-containing thermoplastic elastomers are subsequently regenerated in an efficient manner, for example via an extraction process.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a method for removing organic contaminants from water wherein a thermoplastic elastomer is contacted with the contaminated water.

Contaminated water in the context of the present invention is preferably meant contaminated surface water, drinking water, domestic and industrial waste water and effluents from water purification stations where the concentration of organic contamination is 50 g / l or lower, preferably 10 g / l 1 or lower, preferably 1 g / l or lower, preferably 500 mg / l or lower, preferably 100 mg / l or lower, preferably 1 mg / l or lower, preferably 500 pg / l or lower, at preferably 100 pg / l or lower, preferably 1 pg / l or lower, preferably 500 ng / l or lower, preferably 100 ng / l, preferably 10 ng / l or lower or even 1 ng / l or lower.

Preferably, the concentration of organic impurity is at least 1 pg / l, preferably at least 10 pg / l, preferably at least 100 pg / l, preferably at least 1 ng / l, preferably at least 10 ng / l, preferably at least 100 µg / l, preferably at least 1 pg / l, preferably at least 10 pg / l, preferably at least 100 pg / l, preferably at least 1 mg / l, preferably at least 10 mg / l, preferably at least 100 mg / l, preferably at least 1 g / 10, preferably at least 10 g / l.

By organic contamination, the present invention means the undesired presence of one or more natural or synthetic substances which comprise a steroid skeleton or skeleton derived therefrom. Preferably, these are substances which have a 2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17-hexadecahydro-1 H -cyclopenta [a] phenanthrene skeleton or contain a skeleton derived therefrom, which may comprise one or more unsaturated double bonds, which may comprise 1 or more methyl, hydroxyl, aldehyde, amine, arnide (-NH-CO-R), or oxygen (0 = for formation) of a keto function or -O- to form an oxirane structure) Substituents and which specifically comprises in position 17 Substituents-selected from the group consisting of hydrogen, hydroxyl, oxygen, a hydrocarbon substituent comprising between 1 and 10 carbon atoms which may comprise 1 or more unsaturated bonds and / or 1 or more heteroatoms and which may form a bond with position 16 and an aromatic substituent comprising between 1 and 10 carbon atoms and which may comprise t or more heteroatoms and / or Substituents.

The steroidal substances in the context of the present invention include the group consisting of secosteroids, norsteroids and homosteroids and include natural or synthetic hormones which include glucocorticoids, mineralocorticoids, androgens, estrogens, progestogens and vitamin D.

The organic impurities, specifically intended in the present invention, preferably comprise a 2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17-hexadecahydro -1 H-cyclopenta [a] phenanthrene backbone comprising one or more unsaturated double bonds, one or more methyl Substituents, one or more hydroxyl groups, and in position 17 Substituents selected from the group consisting of hydrogen, hydroxyl, oxygen (0) =, to form a keto function), a C 1 -C 10 saturated hydrocarbon substituent, a C 1 -C 10 unsaturated hydrocarbon substituent comprising 1 or more double and / or triple bonds, and a heteroaromatic.

Specific examples of organic contaminants in the present invention are modified steroids such as, for example, cholesterol, for example present in cosmetics and personal care products; abiraterone, an anti-androgen, and endocrine disruptor substances, such as estrogens, including estriol, estradiol, estrone and ethinyl estradiol.

In one embodiment, the thermoplastic elastomer employed in the present invention is a block copolymer, preferably a tri-block copolymer consisting of hard and soft sequences, the hard sequences being obtained by polymerization of monovinylarene and the soft sequences being obtained by polymerization of alkylenes or by copolymerization of alkylenes and monovinylarene.

In case the alkylene is a conjugated diene, an unsaturated thermoplastic elastomer is obtained; for the case that the alkylene is a monoolefin, a saturated thermoplastic elastomer is obtained.

The monovinylarene is preferably selected from the group consisting of styrene, α-methyl styrene and vinyl toluene. The monovinylarene is preferably styrene.

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, pyperylene, 3-butyl- 1,3-octadiene and phenyl-1,3-butadiene. The alkylene is preferably butadiene, isoprene, to form an unsaturated thermoplastic elastomer, and ethylene, propylene, and butylene to form a saturated thermoplastic elastomer.

The block copolymers to be used in the process 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.

The thermoplastic elastomers preferably employed in the method of the present invention are prepared as described in, for example, WO 1995/35335 or WO 1997/40079 and can be prepared by anionic polymerization in an apolar solvent with the addition of a polar cosolvent or a potassium salt .

The thermoplastic elastomer of the present invention contains between 10 and 60% by weight, preferably between 15 and 50% by weight and more preferably between 20 and 40% by weight of hard sequences.

The thermoplastic elastomers preferably used in the method of the present invention are characterized by a melt flow rate (200 ° C / 5 kg) included between 2 and 50 g / 10 minutes, preferably between 5 and 20 g / 10 min

The thermoplastic elastomers preferably employed in the method of the present invention are block copolymers in which the soft sequence has a molecular weight comprised between 2000 and 250000 g / mol and a glass transition temperature, as determined by differential scanning calorimetry, of 25 ° C or lower and wherein the hard sequence has a molecular weight comprised between 1000 and 200000 g / mol and a glass transition temperature higher than 25 ° C.

The soft sequences preferably have a glass transition temperature, as determined by differential scanning calorimetry, understood between 25 and -110 ° C, preferably between 5 and -100 ° C and more preferably between -10 and -90 ° C or even -20 and -90 ° C.

It is obvious that the thermoplastic elastomers employed in the method of the present invention include other components and / or additives such as thermoplastic homo- and / or copolymers, thermosetting polymers, fillers, wetting agents, surfactants, foaming agents, anti-foaming agents, pigments , dyes, antistatic agents, stabilizers, antioxidants, flow improvers and flame retardants can be included without being bound by any theory that the polymer chains of the thermoplastic elastomers are physically crosslinked by association of the hard polyvinylarene sequences, with the organic contamination is included in the soft sequences.

The glass transition temperature of the soft sequences should be sufficiently low for them to be sufficiently mobile during the purification process to absorb and / or adsorb the contaminants. On the other hand, the glass transition temperature of the hard sequences should be sufficiently high to prevent the thermoplastic elastomers from caking during the purification process.

The density of the thermoplastic elastomer to be used in the method of the present invention is comprised between 0.5 and 1.5 g / cm 3 and preferably between 0.8 and 1.3 g / cm 3.

The thermoplastic elastomer is preferably used in granulate, tube or powder form but can in principle have any form of prevention.

In the method of the present invention, the contaminated water is contacted with the thermoplastic elastomer either stationary with a certain amount of elastomer added to a certain amount of contaminated water, or non-stationary with water, at a certain flow, pumped is fitted by one or more holders, provided with a run-in and run-out opening, filled with thermoplastic elastomer and placed in series or in parallel.

The method of the present invention allows the concentration of organic impurities to decrease by 50%, or more, preferably 60% or more, preferably 70% or more, preferably 80% or more, preferably 90 % or more, preferably 95% or more, preferably 97% or more, preferably 99% or more, preferably 99.5% or more, preferably 99.9% or more relative to the initial concentration.

The method of the present invention allows purified water to be obtained with a concentration of residual organic contamination of 10 g / l or lower, preferably of 1 g / l or lower, preferably of 500 mg / l or lower, at preferably from 100 mg / l or lower, preferably from 1 mg / l or lower, preferably from 500 pg / l or lower, preferably from 100 pg / l or lower, preferably from 1 pg / l or lower, at preferably from 500 ng / l or lower, preferably from 100 ng / l, preferably from 10 ng / l or lower, preferably from 1 ng / l or lower, preferably from 500 pg / l or lower, preferably from 100 pg / l or lower, preferably 10 pg / l or lower, preferably 1 pg / l or lower.

In an embodiment of the stationary method, between 10'7 and 100 g, preferably between 10'5 to 80 g, more preferably between 10'3 to 60 g or even between 10'1 to 50 g of the Thermo-plastic elastomer added to 100 g of contaminated water, depending on the degree of contamination and the type of contamination (s).

The contaminated water is preferably between 0 and 25 ° C, but can be heated if necessary. The thermoplastic elastomer remains in contact with the contaminated water for a period comprised between 1 second and 24 hours, preferably between 10 seconds and 10 hours, depending on the degree of contamination and the type of contamination (s). It is possible to stir during this period.

The thermoplastic elastomer is then separated from the water, for example by filtration. The water may be checked for any impurities still present using, for example, ultra-high performance liquid chromatography combined with multiple reaction monitoring mass spectrometry.

The thermoplastic elastomer can be stripped of the impurities included, for example by a soxhlet type extraction using an apolar solvent such as (cyclo) hexane, isooctane, toluene or xylene. After the extraction, the thermoplastic elastomer is dried, for example, in a convection oven at a temperature of, for example, 50 ° C, optionally under reduced pressure.

The dried granules can be reused in a subsequent water treatment.

In the non-stationary method, use is made of one or more containers filled with thermoplastic elastomer, the contaminated water flowing through the elastomer, for example upwards through the one or more containers, the flow rate of the flowing water according to a embodiment is comprised between 10 and 100,000 parts per hour, preferably between 20 and 75,000 parts per hour, more preferably between 30 and 150,000 parts per hour or even between 50 and 20000 parts per hour, depending on the degree of contamination and the type of contamination (s), for one or more containers containing a total of 100 parts of thermoplastic elastomer.

The contaminated water that flows through the one or more containers is preferably at a temperature comprised between 0 and 25 ° C, but can, if necessary, be heated up in advance, whereby the one or more containers can be adiabatically closed.

Analysis of the outflowing water makes it possible to determine when one or more containers must be replaced, after which the thermoplastic elastomer of the one or more replaced containers can be recycled as described above.

For both, the stationary and non-stationary method, salt can 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.

For this purpose, for example, sodium chloride can be added to the contaminated water to obtain a concentration comprised between 100 and 350 g of salt per liter of water.

Examples The example below is intended to illustrate the invention and does not in any way limit the invention.

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

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

A 50 liter reactor was charged with 22.8 liters of dry cyclohexane and 1638 grams of dry styrene and brought to 40 ° C with the polymerization initiated by addition of 87.3 mmol of sec-butyllithium (12 weight percent in dry cyclohexane) and 2.36 mmol of potassium tert. -amylate (5% by weight in dry cyclohexane). The reaction mixture was stirred for 30 minutes while maintaining a temperature of 68 ° C.

The reaction mixture was then cooled to 50 ° C and 1250 grams of butadiene and 1126 grams of styrene were added simultaneously. The temperature rose to 74 ° C. After a polymerization time of 13 minutes, the resulting reaction mixture was cooled to 55 ° C and a second amount consisting of 1250 grams of butadiene and 1126 grams of styrene was added. The temperature rose to 76 ° C. After a polymerization time of 13 minutes, the mixture was cooled to 550 ° C and a third quantity consisting of 1250 grams of butadiene and 1126 grams of styrene was added with the temperature rising to 75 ° C. After 17 minutes, 1638 grams of styrene were added at a temperature of 70 ° C with the temperature rising to 80 ° C.

40 minutes after the styrene addition, the polymerization was terminated by the addition of 200 mmol isopropanol, acidified by the addition of carbon dioxide and water and stabilized by the addition of 35 grams of Irganox® 3052 and 80 grams of Weston® TNPP. The polymer was then stripped of solvent and transformed into granulate form via an extruder.

The thermoplastic elastomer was characterized by a number average molecular weight of 140000 g / mol and 2 glass transition temperatures, the first glass transition temperature being between -25 and -55 ° C and the second glass transition temperature being between 60 and 100 ° C.

The thermoplastic elastomer contains 31.5 weight percent of polystyrene block.

Example 2 .: Purification of an industrial waste water sample An industrial water sample (sample 1) was collected at the outlet and analyzed for 17α-estradiol, 17β-estradiol, estrone and ethinyl estradiol. 100 g of the thermoplastic elastomer of example 1 are added to a container containing 200 g of contaminated water, the whole being kept at 40 ° C for 6 hours. The thermoplastic elastomer was then filtered off and the purified water (sample 2) was analyzed.

To illustrate the effect of the thermoplastic elastomer, a contaminated water sample was kept at 40 ° C for 6 hours, albeit in the absence of the thermoplastic elastomer. The water steel (sample 3) was then analyzed.

Table 1 shows the concentrations, in nanograms per milliliter, of 17α-estradiol, 17β-estradiol, estrone and ethinyl estradiol for the different water samples (samples 1, 2 and 3).

Table Table 1 clearly demonstrates the effect of the thermoplastic elastomer on reducing contaminants; a decrease of at least 80% of the initial values is achieved.

Claims (15)

Conclusions A method for removing organic contaminants, which comprise a steroid skeleton or skeleton derived therefrom, from water, comprising contacting the contaminated water with a thermoplastic elastomer. The method of claim 1 wherein the organic contaminants comprise a 2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17 hexadecahydro-1 H-cyclopenta [a] phenanthrene skeleton or a skeleton derived therefrom that: one or more unsaturated double bonds may include one or more methyl, hydroxyl, aldehyde, amine, amide (-NH-CO-R), or oxygen Substituents and in position 17, Substituents selected from the group consisting of from hydrogen, hydroxyl, 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 - can 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. The method according to claim 1 wherein the organic impurities comprise a 2.3.4.5.6.7.8.9.10.11.12.13.14.15.16.17 hexadecahydro-1 H-cyclopenta [a] phenanthrene skeleton comprising one or more unsaturated bonds, - one or multiple methyl Substituents, - comprises one or more hydroxyl groups and - in position 17 Substituents comprises selected from the group consisting of hydrogen, hydroxyl, oxygen (0 =, to form a ketofunction), C1 -C10 aliphatic hydrocarbon Substituents, C1- C10 unsaturated hydrocarbon Substituents comprising 1 or more unsaturated double and / or triple bonds, and a heteroaromatic .. The method according to any of claims 1 to 3, wherein the organic contaminant is a natural or synthetic hormone or hormone analogue. The method of any one of claims 1 to 4 wherein the organic contaminant is a endocrine disruptor endocrine disruptor. The method of any one of claims 1 to 5, wherein the thermoplastic elastomer is a block copolymer comprising hard sequences obtained by polymerization of monovinylarenes and soft sequences obtained by polymerization of alkylenes or by copolymerization of monovinylarenes and alkylenes. The method of any one of claims 1 to 6, wherein the thermoplastic elastomer comprises between 10 and 60 weight percent, preferably between 15 and 50 weight percent and more preferably between 20 and 40 weight percent hard sequences. The method of any one of claims 1 to 7, wherein the thermoplastic elastomer is 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. The method of any one of claims 1 to 8, comprising the steps of: a) adding thermoplastic elastomer to contaminated water; b) absorbing and / or adsorbing the organic contaminant (s) in the thermoplastic elastomer. The method of claim 9, wherein in step a) between 10'7 and 100 parts, preferably between 10'5 and 80 parts, more preferably between 10'3 and 60 parts or even between 10'1 and 50 parts thermoplastic elastomer can be added for 100 parts of water. The method according to claim 9 or 10, wherein step b) takes place over a period of time comprised between 1 second and 24 hours, preferably between 10 seconds and 10 hours, more preferably between 20 seconds and 6 hours. The method according to any one of claims 1 to 8, wherein the contaminated water is pumped through one or more containers that are completely or partially filled with thermoplastic elastomer, wherein several reactors are arranged in series and / or in parallel and wherein the contaminated water preferably flows in upward direction through the container (s). The method of claim 12, wherein the flow rate of contaminated water through the container (s) is comprised between 10 and 100,000 parts per hour, preferably between 20 and 75,000 parts per hour and more preferably between 30 and 50,000 parts per hour or even between 50 and 20000 parts per hour for a total of 100 parts of thermoplastic elastomer present in the container (s). The method according to any of claims 9 to 13, comprising an additional step in which the contaminant-containing thermoplastic elastomer is isolated and regenerated, preferably via an extraction process. The use of the method according to any of claims 1 to 14 for purifying skin water, industrial waste water, surface water, drinking water and effluents from water treatment stations.