Use of a cyclodextrin polycondensate or a composition comprising such a polycondensate, as a capturing agent

Abstract

The use of a cyclodextrin polycondensate or a composition comprising at least one cyclodextrin polycondensate, as an agent for capturing at least one substance chosen from a metal element and an organic molecule having an octanol/water partition coefficient, referred to as Log Kow, greater than or equal to 2, the cyclodextrin polycondensate being obtained by reacting the following compounds (A) to (C): (A) at least one cyclodextrin, (B) at least one linear, branched or cyclic polycarboxylic acid, that is saturated, unsaturated or aromatic, and (C) at least one ethylene vinyl alcohol copolymer (EVOH).

Claims

1. A method of sequestering a pollutant, comprising: contacting said pollutant with a cyclodextrin(s) polycondensate, or a composition comprising at least one cyclodextrin(s) polycondensate, wherein the pollutant comprises at least one substance chosen from a metal element at the degree of oxidation 0 and an organic molecule selected from the group consisting of diuron, carbamazepine, polychlorinated biphenyls, phthalates and benzopyrene, and wherein the cyclodextrin(s) polycondensate is obtained by reacting the following compounds (A) to (C): (A) at least one cyclodextrin, (B) a saturated aliphatic polycarboxylic acid that is linear or branched, and (C) at least one ethylene vinyl alcohol copolymer (EVOH).

2. The method according to claim 1, wherein the pollutant is a metal element at the degree of oxidation 0 selected from the group consisting of aluminum, silver, iron, boron, tin, copper, zinc, lead, nickel, cadmium, chromium, mercury and gold.

3. The method according to claim 1, wherein the pollutant is present in the air, in the ground or in water.

4. The method according to claim 1, wherein the composition further comprises at least one compound chosen from metal oxides, activated carbon, paints, magnetic compounds and antibacterial agents.

5. The method according to claim 1, wherein the compound (B) is selected from the group consisting of malic acid, citric acid, 1,2,3-propanetricarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, oxydisuccinic acid and thiodisuccinic acid.

6. The method according to claim 1, wherein the cyclodextrin is chosen from the group consisting of -cyclodextrin, -cyclodextrin and -cyclodextrin.

7. The method according to claim 1, wherein the reaction comprises one cyclodextrin.

8. The method according to claim 1, wherein the reaction comprises a mixture of cyclodextrins.

9. The method according to claim 8, wherein the mixture comprises, based on the total weight of said mixture, the following mass proportions: from 10% to 60% of -cyclodextrin, and from 40% to 90% of -cyclodextrin or of -cyclodextrin.

10. The method according to claim 9, wherein the mixture comprises, based on the total weight of said mixture, the following mass proportions: from 25% to 40% of -cyclodextrin, and from 60% to 75% of -cyclodextrin or of -cyclodextrin.

11. The method according to claim 8, wherein the mixture comprises, based on the total weight of said mixture, the following mass proportions: from 30% to 70 of -cyclodextrin, from 20% to 40% of -cyclodextrin, and from 10% to 30% of -cyclodextrin.

12. The method according to claim 11, wherein the mixture comprises, based on the total weight of said mixture, the following mass proportions: from 44% to 56% of -cyclodextrin, from 27% to 33% of -cyclodextrin, and from 17% to 23% of -cyclodextrin.

13. The method according to claim 1, wherein the compound (B) is citric acid.

14. The method according to claim 1, wherein the reaction comprises, based on the total weight of the compounds (A) to (C), the following mass proportions: from 15% to 60 of one or several cyclodextrins, from 0.5% to 12 of one or several compounds, and from 39.5% to 84.5%, of EVOH.

15. The method according to claim 14, wherein the reaction comprises, based on the total weight of the compounds (A) to (C), the following mass proportions: from 26% to 44% of one or several cyclodextrins, from 2% to 6% of one or several compounds, and from 54% to 72% of EVOH.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a histogram showing the abatement rates, noted as Ab and expressed as a %, showing the residual mass concentrations in Pb and in Ni in relation to their initial mass concentrations in each one of the solutions S1 to S3.

(2) FIG. 2 is a histogram showing the abatement rates, noted Ab and expressed as a %, showing the residual mass concentrations in diuron, noted as diuron, and in carbamazepine, noted as carba, in relation to their initial mass concentrations in each one of the solutions S4 and S5.

DETAILED DESCRIPTION OF PARTICULAR EMBODIMENTS

Example 1: Preparation of Cyclodextrin(S) Polycondensates

(3) Three cyclodextrin polycondensates noted as P1, P2 and P3, and a cyclodextrins polycondensate, noted as P4, were prepared using the mass proportions of the compounds (A) to (C) such as mentioned in the table 1 hereinbelow.

(4) TABLE-US-00001 TABLE 1 (A) - - - (B) (C) Com- cyclodextrin cyclodextrin cyclodextrin citric acid EVOH pounds (%) (%) (%) (%) (%) P1 28.6 3.0 68.4 P2 28.6 3.0 68.4 P3 28.6 3.0 68.4 P4 14.3 8.6 5.7 3.0 68.4

(5) Each one of these cyclodextrin(s) polycondensates P1 to P4 has the form of a solid yellow block.

Example 2: Decontamination of Aqueous Solutions Containing Metal Elements

(6) Nickel Ni and lead Pb, at the degree of oxidation 0, are substances that are very commonly found in waste water and in drinking water.

(7) In order to examine the effectiveness, as capturing agent, of cyclodextrin polycondensate P2 prepared hereinabove then ground in the form of a powder having an average particle size of 1 mm, three aqueous solutions, noted as S1 to S3, were prepared: the solution S1 contains 0.1 g/L of Ni.sup.0 and 0.1 g/L of Pb.sup.0 in waste water, the solution S2 contains 0.1 g/L of Ni.sup.0 and 0.1 g/L of Pb.sup.0 in drinking water, and the solution S3 contains 0.5 g/L of Ni.sup.0 and 0.5 g/L of Pb.sup.0 in drinking water.

(8) In reference to FIG. 1, it is observed that abatements are obtained ranging between 35% and more than 70% for lead and between 14% and 63% for nickel, the highest values being reached when these metal elements are contained in drinking water.

Example 3: Decontamination of Aqueous Solutions Containing Organic Molecules

(9) Diuron is a pesticide with empirical formula C.sub.9H.sub.10Cl.sub.2N.sub.2O, of a Log Kow of 2.68, that is frequently detected in water resources that can be used for the production of water intended for human consumption.

(10) Carbamazepine is a drug with empirical formula C.sub.15H.sub.12N.sub.2O, of a Log Kow of 2.45, that is frequently found in waste water, in river water and in some drinking water.

(11) As these substances are both considered as particularly harmful for wildlife and, what is more, as they are not treated by water treatment plants, there is a major interest in decontaminating them from the areas that contain them.

(12) In order to examine the effectiveness, as capturing agent, of the cyclodextrin polycondensate P2 prepared hereinabove then ground in the form of powder having an average particle size of 1 mm, two aqueous solutions, noted as S4 and S5, were prepared: the solution S4 contains 0.1 g/L of diuron and 0.1 g/L of carbamazepine in waste water, and the solution S5 contains 0.5 g/L of diuron and 0.5 g/L of carbamazepine in drinking water.

(13) In reference to FIG. 2, it is observed that abatements are obtained ranging between 3% and 15% for diuron and between 2% and 14% for carbamazepine, the highest values being reached when these metal substances are contained in an initial mass concentration of 0.5 g/L.

(14) Although the abatement rates of this example are lower than those reached in the example 2 hereinabove, they remain however interesting with regards to the dangerousness of these two substances, diuron and carbamazepine.

Example 4: Decontamination of Aqueous Solutions Containing Organic Molecules

(15) In this example, the tests were conducted using aqueous solutions, noted as S6 to S14, comprising water taken from the outlet of La Folie treatment plant, in Poitiers (France) and separated from any of its suspended matter, via settling.

(16) The cyclodextrin(s) polycondensates P1 to P4 obtained in the example 1 hereinabove were ground in the form of a powder of an average particle size of 1 mm then subjected to successive washings with demineralised water, at a rate of 3.49650 g/L of demineralised water.

(17) The operating protocol followed is the same for all of the tests, which moreover were conducted at a temperature between 10 C. and 15 C.

(18) Stock solutions of the substances to be studied were prepared in organic solvents. Aliquots of each one of these stock solutions are added to 1.5 L of the water taken and settled, noted as E, in order to reach mass concentrations of 5 g/L of water E in the aqueous solutions S6 to S14 constituted as such.

(19) 0.5 mL of each one of these aqueous solutions were introduced into 3 series of glass bottles, noted as F1, F2 and F3.

(20) Into each of the bottles F1 to F3, 3.49650 g/L of cyclodextrin polycondensate P1, P2 or P3 and 4.789270 g/L of the cyclodextrins polycondensate P4 were introduced.

(21) The bottles F1 are briefly stirred while the bottles F2 and F3 are placed under stirring by turning over at a speed of 10 rpm, for 10 min for the bottles F2 and for 60 min for the bottles F3.

(22) At the end of these stirrings and after a settling for 10 min, the water is recovered for analysis.

(23) The solutions S6 to S14 prepared as such are mentioned in the table 2 hereinbelow.

(24) TABLE-US-00002 TABLE 2 Aqueous solutions Substances Family Log Kow S6 PCB 28 polychlorinated biphenyls 5.62 S7 PCB 52 polychlorinated biphenyls 6.12 S8 PCB 101 polychlorinated biphenyls 6.8 S9 PCB 118 polychlorinated biphenyls 6.84 S10 PCB 138 polychlorinated biphenyls 7.25 S11 PCB 153 polychlorinated biphenyls 7.21 S12 PCB 180 polychlorinated biphenyls 7.7 S13 benzopyrene polycyclic aromatic 6.07 hydrocarbons S14 di(2-ethylhexyl)- phthalates 7.6 phthalate

(25) The tests were conducted with each one of the cyclodextrin(s) polycondensates P1 to P4. The residual mass concentrations in substances measured in the residual water of the bottles F1 to F3, as well as the corresponding abatement rates after 60 min of stirring, are indicated in the tables 3 to 6 hereinafter.

(26) TABLE-US-00003 TABLE 3 Abatement Aqueous Mass concentration (g/L) rate at 60 min Compound solutions 0 min 10 min 60 min (%) P1 S6 2.8 1.3 1.1 60 S7 3.2 1.8 1.4 56 S8 3.3 2.9 2.5 24 S9 4.3 4.8 3.9 9 S13 5.0 5.7 4.5 10 S14 4.9 4.2 4.5 8

(27) TABLE-US-00004 TABLE 4 Abatement Aqueous Mass concentration (g/L) rate at 60 min Compound solutions 0 min 10 min 60 min (%) P2 S6 2.6 1.9 1.2 54 S7 3.1 2.3 1.6 48 S8 3.6 2.8 2.2 39 S9 5 4.3 3.3 34 S10 4.9 4.7 3.9 20 S11 4.6 4.4 3.9 15 S13 5.2 4.3 2.1 60 S14 5.2 4.5 4.1 21

(28) TABLE-US-00005 TABLE 5 Abatement Aqueous Mass concentration (g/L) rate at 60 min Compound solutions 0 min 10 min 60 min (%) P3 S6 2.9 1.9 1.3 55 S7 3.3 2.6 1.9 42 S8 3.5 2.8 2.4 31 S9 4.6 4.2 3.5 24 S11 4.3 4.2 4.0 7 S13 4.9 4.8 3.7 24 S14 4.4 4.6 4.1 7

(29) TABLE-US-00006 TABLE 6 Abatement Aqueous Mass concentration (g/L) rate at 60 min Compound solutions 0 min 10 min 60 min (%) P4 S6 2.1 2.1 1.4 29 S7 2.6 2.7 2.0 23 S8 3.7 2.9 2.2 40 S9 5.7 3.8 3.1 46 S10 6.2 4.1 3.6 42 S11 5.6 3.9 3.5 38 S12 7.5 5.2 5.0 33 S13 5 3.9 2.7 46 S14 5.3 4.5 4.0 25

(30) Good abatement rates of the different substances present in the aqueous solutions S6 to S14 are observed.

(31) Note, as examples: that the cyclodextrin polycondensate P1 is more effective on the substances PCB 28 and PCB 52 (aqueous solutions S6 and S7) than the other cyclodextrin(s) polycondensates P2, P3 and P4, that the cyclodextrin polycondensate P2 is more effective on the substances PCB 101 and PCB 118 (aqueous solutions S8 and S9) than the other cyclodextrin polycondensates P1 and P3, and that the cyclodextrins polycondensate P4 offers a very satisfactory effectiveness on all of the substances.

(32) The choice of the cyclodextrin(s) polycondensate can therefore be optimised according to the nature of the substances of which the areas must be decontaminated.

BIBLIOGRAPHY

(33) [1] WO 2014/095427 A1