ES2334756B1 - POLYMERIC MATRICES BASED ON POLYSACARIDS AND CYCLODEXTRINES. - Google Patents

Abstract

Polymeric matrices based on polysaccharides and cyclodextrins The present invention relates to new materials based on polymeric matrices obtained from polysaccharides, to its procurement procedures and its uses. More particularly refers to the use of these materials based on starch, dextrin or cyclodextrins to sequester organic and inorganic contaminants and for water purification.

Description

Polymeric matrices based on polysaccharides and cyclodextrins

The present invention relates to new materials based on polymeric matrices obtained from polysaccharides, their procedures for obtaining and their uses. Plus particularly, it refers to the use of these materials based on starch, dextrin or cyclodextrins to sequester contaminants organic and inorganic and for water purification.

Prior art

Environmental policy is taking more and more relevance. For example, the European Union treaty has between its fundamental principles, conservation, protection and improvement of water quality as well as prudent and rational use of natural resources (Art. 130R of the Treaty of the Union European). One of the points in which it has been legislated with greater intensity refers to reducing pollution levels of surface water, which is applied to domestic wastewater, rainwater and industrial wastewater. In spite of this normative effort citizens' concern about the problem  of water pollution is corroborated by Different official reports. For example, the detection of toxic metals (e.g. Se, Zn and Cr) and compounds Toxic organic Obviously, water pollution transcends the ecological and economic frameworks and can become a serious health problem

Decontamination of wastewater is a key element to not compromise the subsequent use, public or private, let them be done. In this context, the design of new materials to remove contaminants and restore initial water conditions for reuse is an area priority for the conservation, maintenance and improvement of natural heritage.

The operation of any industry it requires large amounts of water, which when intervening in industrial processes, it is contaminated. Similarly, the use of Agricultural pesticides contribute to pollution. The presence of pollutants in the waters that return to the nature compromises its subsequent use, so the treatment Wastewater is a priority objective. The restoration of The initial water conditions will depend largely on the nature of the contaminants present in the discharge. In lines general, pretreatments (physical), treatments are made primary (physical-chemical), secondary (biological) and tertiary (specific according to the characteristics of the discharge). Tertiary treatments are the most specific and those who have had more progress with the new technologies. By way For example, there are biological treatments, membrane processes, advanced oxidation processes, chemical techniques and electrochemical and adsorption processes. However, adsorption on active carbons, zeolites, clays, silica and different polymeric materials is the most widespread method, being the active coals the most used material, despite its high cost, especially in relation to its regeneration, which takes out especially by thermal means. That is why there is interest in development of new adsorbents that are insoluble, effective, Regenerable and cheaper.

An attractive alternative is the design of materials based on polysaccharides (Crini, G., Progress in Polymer Science (2005), vol. 30, pp. 38-70) because their availability and low cost are combined with their structural characteristics, physical properties -chemistry, stability and presence of reactive groups (hydroxyl, acetamido or amino) that give them selectivity against metals and aromatic compounds. In recent years the development of this type of materials for use as adsorbents and interest in them has been growing. The most commonly used polysaccharide in decontamination applications has been chitosan (Crini, G. et al., Progress in Polymer Science (2008), vol. 33, pp. 399-447), a natural homopolymer with a structure analogous to Cellulose with amino groups in C-2 positions that gives it characteristic adsorption properties and facilitates the introduction of chemical modifications. However, at present the interest extends to other polysaccharides, such as cyclodextrins (CDs) or starch.

The CDs are cyclic oligosaccharides consisting of different D-glucose units (6: α-CD, 7: β-CD and 8:
γ-CD) with an α-1,4 junction that results in the formation of a hydrophobic toroidal cavity bounded by a hydrophilic outer surface. The cavity is responsible for its use for the removal of organic pollutants because of its ability to form inclusion complexes with a wide variety of organic and inorganic compounds (Szejtli, J., Chemical Reviews (1998), vol. 98, pp. 1743-1753), both in solution and in solid phase through host-host interactions.

Cyclodextrins have served as starting material for the preparation of various crosslinked homogeneous polymer matrices. As crosslinking agents, epichlorohydrin and diisocyanates have been used. Some materials based on the cross-linking of β-CD with epichlorohydrin (Kiji, J., et al., Angewandte Makromolekulare Chemie (1992), vol. 199, pp. 207-210) have been used for the adsorption of phenol, 4 -methylbiphenyl and sodium dodecyl benzene sulfonate, bisphenol A and dibenzofuran and its derivatives. The materials resulting from the cross-linking of CDs with diisocyanates (Mhlanga, SD, et al., Journal of Chemical Technology and Biotechnology (2007), vol. 82, pp. 382-388) have the capacity to eliminate aromatic compounds.

The CDs have also been used to obtain heterogeneous or mixed polymer matrices. Thus, the cross-linking of β-CD and carboxymethyl cellulose with different cross-linking agents has resulted in the obtaining of polymers having carboxylic groups in their structure that favor the adsorption of cationic dyes (Crini, G., Dyes and Pigments (2008 ), vol. 77, pp. 415-426). The combination of β-CD with starch using diisocyanates as crosslinking agents leads to materials capable of removing azo dyes (Ornen, EY, et al., Bioresource Technology (2008), vol. 99, pp. 526- 531).

Starch-based materials include cationic starches (Delval, F., et al., Bioresource Technology (2006), vol. 97, pp. 2173-2181) developed primarily for the removal of anionic dyes. Thus, the cross-linking of starch with epichlorohydrin in the presence of NH4OH allows to obtain materials containing tertiary amines that confer improved properties for the removal of certain dyes that possess anionic groups. Anionic starches have also been synthesized (Khalil, MI, et al., Journal of Applied Polymer Science (1998), vol. 69, pp. 45-50) via succinylation with succinic anhydride in basic medium, by oxidation with sodium hypochlorite resulting in to materials that have been used as heavy metal adsorbents such as Cu 2+, Zn 2+, Pb 2+ and Cd 2+. However, oxidized starch is partially soluble in water and this is a problem. The cross-linking of starch and subsequent incorporation of the desired functional groups is an option that allows insoluble materials to be obtained and then the desired groups. In this sense, the carboxymethylation of starch crosslinked with POCl3 using sodium chloroacetate leads to materials whose efficiency to adsorb metals increases with the degree of substitution of carboxymethyl groups and whose desorption by washing with acidic solutions allows partial regeneration of the material.

In the synthesis of polymer based matrices in polysaccharides crosslinking agents can be used. The nature and structure of the crosslinking agent plays a active role in the adsorption process of contaminants, so that very different properties of polymeric matrices are obtained crosslinked using the same polysaccharides but crosslinked with different crosslinking agents. The agents or reagents crosslinking must have at least two reactive groups, which they are normally located in terminal positions, and can be homofunctional or heterofunctional, depending on which groups reagents are the same or different. Reagents of crosslinking most used for chain crosslinking Polymers are:

to)

Epifohydrin (EPI) bifunctional compound that It contains two different functional groups and has a high reactivity against hydroxyl groups under conditions alkaline

b)

Dialdehydes that have been used for cross-linking of polymers containing amino groups through Schiff's base formation.

C)

Diisocyanates, such as 1,6-hexamethylene diisocyanate (HMDI or HMI) that react with hydroxyl groups, leading to the formation of carbamates, and with amines, leading to the formation of ureas

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A particular crosslinking agent is the divinylsulfone (DVS). The DVS, as such, has been used in the cross-linking of different polysaccharides to obtain gels and on gel supports. The DVS is able to react with hydroxyl groups present in polysaccharide chains under alkaline conditions (pH> 10).

Under these conditions, dextran crosslinking has been carried out (Young, NM, et al., Carbohydrate Research (1978), vol. 66, pp. 299-302) allowing obtaining gels that have been used in affinity chromatography for purification of lectins and in the development of systems for protein retention and release.

The carboxymethyl cellulose (CMC) and hydroxyethylcellulose (HEC) cellulose derivatives have been crosslinked using DVS, for the development of superabsorbent materials (Anbergen, U., et al., Polymer (1990), vol. 31, pp. 1854-1858) . Cellulose hydrogels have been synthesized with DVS and their ability to remove water from the body has been demonstrated. This ability to retain large amounts of water can also be used to obtain absorbent and biodegradable products for personal hygiene.

Cross-linked hyaluronic acid (HA) from hyaluronic acid with DVS results in a gel that is called "hylan b" or "hylaform" (Larsen, NE, et al., Materials Research Society Symposium Proceedings (1995), vol. 394, pp. 149-53). Several authors (Piacquadio, D., et al., Journal of the American Academy of Dermatology (1997), vol. 36, pp. 544-549) have revealed the potential of "hylan b" as a filling material in surgery aesthetic, being able to be used in implants and fillers. Other authors (Ramamurthi, A., et al, Biomaterials (2005), vol. 26, pp. 999-1010) have shown that these HA hydrogels crosslinked with DVS are capable of stimulating cell adhesion and proliferation. This property makes this type of materials of great importance in materials engineering for the development of bioartificial organs or biohybrid organs.

Through the use of DVS (Sannino, A., et al., Biomacromolecules (2004), vol. 5, pp. 92-96) the crosslinking of HA with CMC mixtures has been carried out for use as soft tissue after a surgery. The synthesis of CD gels with cellulose has also been carried out using hydroxypropyl-? -Cyclodextrin (HP-? -CD), the beta-CD itself and various cellulose derivatives (HPC, HPMC, CMC) and The ability of CDs to form inclusion complexes with different organic molecules has been exploited for their use in the removal of bisphenol-A from aqueous solutions (Transactions of the Materials Research Society and Macrocyclic Chemistry (2003), vol 56, pp. 55-59).

Description of the invention

In the present invention a new one is provided material based on polymeric matrices obtained from polysaccharides or mixtures of polysaccharides (eg starch, dextrin and cyclodextrins) and crosslinked with at least one sulfone α-β unsaturated as an agent of crosslinking, and the use of said polymeric matrices, especially in the decontamination of organic compounds and Inorganic water. Some of the advantages of this invention are: high efficiency, versatility, conditions and Simple reaction procedures, low economic cost for both the starting materials as for the overall process and sustainable chemistry procedures that are environmentally friendly ambient. Other advantages is that the matrices of this invention can be reused, without loss of efficiency. In addition, the polymeric matrices of the present invention possess a large dimensional stability and rigidity, against water absorption, compared to the gels described in the state of the art, and this greater dimensional stability and stiffness surprisingly not It entails a loss in its effectiveness.

The first aspect of the present invention is a polymeric matrix characterized in that it comprises units of polysaccharides crosslinked with a crosslinking agent. TO from abundant and economic raw materials such as natural polysaccharides starch, dextrin, inulin, etc. Y cyclic oligosaccharides (cyclodextrins) matrices have been obtained Polymers capable of decontaminating water by simple methods and easy to implement on an industrial scale. In addition the matrices Polymers obtained from polysaccharides have, due to their Chemical nature, high biodegradability.

Preferably the crosslinking agent is at least one unsaturated α-β sulfone, preferably a vinyl sulfone. In a preferred embodiment the crosslinking agent has more than one vinyl group such as bis-vinyl sulfone, with divinyl sulfone being even more preferred, preferably selected from H 2 C = CHSO 2 RSO 2
CH = CH 2, H 2 C = CHSO 2 CH 2 CH 2 XRXCH 2 CH 2 SO 2 CH = CH 2 where R is an alkyl (C_ {1} -C 10), a dialkylaryl ((C 1 -C 10) Ar (C 1 -C 10), (CH 2 CH 2 O) n} CH 2 CH 2 with n = 2-20, where X is O or S, and mixtures thereof, from abundant and economical raw materials such as natural polysaccharides starch, dextrin, inulin, etc. and cyclic oligosaccharides (cyclodextrins) are obtained polymeric matrices by cross-linking with an unsaturated α-β-sulfone, preferably a bisvinylsulfones, using for example easy-to-carry out reactions such as Michael's addiction. This methodological approach uses the native functional groups present in the aforementioned polymers, it is highly versatile, efficient, simple and environmentally friendly, since it can be carried out in an aqueous medium This methodology exploits the functional groups present intrinsically in the aforementioned starting materials evit thus a derivatization stage for the introduction of suitable reactive functions.

Plus sulfones unsaturated α-?, and especially the bisvinylsulfones, are compounds that are easy to prepare and handle so they constitute a powerful tool in synthesis organic As Michael's acceptors they can react with amines, thiols, or alcohols giving rise to heterosulfones β-substituted. Thus, bisvinylsulfone as crosslinking agents react with a wide range of substrates presented as advantages of being chemically stable, economically competitive and attractive from a point of view of ecological, as crosslinking reactions can be carried out in water. On the other hand they are extremely versatile, because different spacer systems can be introduced between Vinyl sulfone functions that allow distance play (spacer length), hydrophobicity (contribution to hydrophilicity of polymeric material) and even participate in pollutant interactions (via stacking pi-pi in the case of spacers with rings aromatic and organic pollutants or interactions electrostatic between metals and spacers of the type polyethylene glycol), embodiments that are part of the present invention.

In a preferred embodiment, the polysaccharide is selected from, starch, modified starch, chitosan, cellulose, inulin, cyclodextrins, modified cyclodextrins, amylose, amylopectin, dextrin and mixtures thereof.

The polysaccharide can be linear, preferably selected from starch, dextrin or mixtures of they.

In another embodiment the polysaccharide is of type cyclic, preferably α, β, γ-cyclodextrins or mixtures thereof.

The matrices can be crosslinked using the minus two polysaccharides, which gives it synergistic properties in the elimination of contaminants. For example crosslinking between starch and beta cyclodextin increases absorption capacity of bisphenol A in greater proportion than the matrices that are constituted by a single polysaccharide. In other cases the capacity of absorption is maintained, but this is a great advantage, because this means that although the present amount of cyclodextrin is has significantly reduced the absorption capacity of the matrix is has maintained at the same level as using only cyclodextrin. Such synergy is interesting because, among other things, the cyclodextrin is usually much more expensive than starch, so that we have a matrix with the same absorption properties but at a lower price. Preferably the polymer matrix comprises two polysaccharides selected from starch, modified starch, chitosan, cellulose, inulin, cyclodextrins, cyclodextrins modified, amylose, amylopectin, dextrin and mixtures of they.

In case the matrix understands at least two polysaccharides, the proportions of the two polysaccharides can vary, and preferably the proportion is between 0.1 at 10 by weight and more preferably between 0.25 and 4 by weight, even more preferably between 0.5 and 2 by weight. In one embodiment Particularly the polymer matrix comprises at least one starch and a cyclodextrin, and preferably in a proportion between 0.1 to 10 by weight and more preferably between 0.25 and 4 by weight, even more preferably between 0.5 and 2 by weight.

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The cyclodextrins of the present invention are preferably select between?,?, and? mixtures of them, since they are the most readily available.

The present inventors have found that polymeric matrices of the present invention can be derivatized easily and enter, for example, electrostatic charges positive or negative, which surprisingly provides you with a highly desired absorption properties in the removal of ions in solution. An additional use of loaded matrices is the absorption and / or elimination of ions from non-water media residuals, as it would be ion exchange chromatographs, or Do the function of ion exchange resins.

The introduced charge may be of a different nature, but preferably this is introduced by incorporating derivatives selected from the list comprising derivatives that possess carboxylic acids, sulfonic acids, or amino groups and mixtures thereof. Preferred derivatives for charge introduction are selected from the list comprising H 2 N (CH 2) n COOH (where n = 1-20), HS (CH 2) n COOH (where n = 1-20), HN [(CH 2) n
COOH] 2 (n = 1-3), HOCH 2 CH 2 N (CH 3) 3, HN [CH 2 CH 2 CH 2 NMe_ { 2] 2, HN [(CH 2) n Py] 2 (where n = 0-1 and Py = 2-pyridyl) and mixtures thereof.

The amount of cargo preferably introduced is between 50 and 800 microequivalents of acid or base per gram of polymer matrix. In a particular embodiment the amount of Load is between 200 to 400 microequivalents.

In a particular embodiment of the first aspect of the present invention is a polymeric matrix that understands:

to)

A polysaccharide selected from starch, dextrin, cyclodextrins and mixtures thereof, preferably It comprises at least starch and a cyclodextrin.

b)

At least one bis-vinyl sulfone, preferably divinylsulfone;

C)

A derivative of a carboxylic acid selected from the list comprising H 2 N (CH 2) n COOH (where n = 1-20), HS (CH 2) n COOH (being n = 1-20), HN [(CH 2) n COOH] 2 (n = 1-3), HOCH 2 CH 2 N (CH 3) 3, HN [CH 2 CH 2 CH 2 NMe 2] 2, HN [(CH 2) n Py] 2 (being n = 0-1 and Py = 2-pyridyl) and mixtures of they.

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The second aspect of the present invention is a process for the synthesis of a polymeric matrices valid for the synthesis of the matrices of the first aspect and for any of Your particular realizations. The process includes at least the following stages:

i)

Dissolve the polysaccharide or polysaccharides, preferably in buffer at pH between 9 and 13, and more preferably between 10 and 12, and heating if necessary to get the dissolution.

ii)

add the crosslinking agent, preferably a vinyl sulfone.

iii)

the resulting mixture is kept under stirring, preferably at least 1 h, and more preferably between 3 and 12 h.

iv)

the polymer is filtered and washed resulting

v)

the polymer is dried, preferably at temperature lower 55 ° C and under vacuum conditions.

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If the introduction of cargo is desired, it can be introduced into the matrix by adding the agent responsible for the incorporation of cargo after step ii). The filler may be selected from the list comprising carboxylic acid derivatives, amino group derivatives and mixtures thereof. Preferably it is selected from the list comprising H 2 N (CH 2) n COOH (where n = 1-20), HS (CH 2) n COOH (where n = 1 -20), HN [(CH 2) n COOH] 2 (n = 1-3), HOCH 2 CH 2 N (CH 3) 3, HN [CH 2 CH 2 CH 2 NMe 2] 2, HN [(CH 2) n Py] 2 (where n = 0-1 and
Py = 2-pyridyl) and mixtures thereof.

The third aspect of the present invention are polymeric matrices obtainable by the processes defined in any of the processes of the second aspect. The process of described production allows to obtain polymeric matrices rigid and dimensionally stable against the absorption of Water.

The fourth aspect of the present invention is the use of the polymer matrices described in the first and third appearance. These have been shown to be useful for purification and / or water treatment, preferably waste, and especially in the reduction or elimination of contaminants. Typical pollutants that the present matrices are able to absorb they are for example; neutral organic compounds, preferably steroids, preferably progesterone, phenol and derivatives of phenol.

Arrays with load have proven useful in the absorption, reduction or elimination of ions, preferably heavy metal (e.g. Cr 3+, Cd 2+ and Pb 2+). Preferably these ions are absorbed and / or removed from water, preferably residual.

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The fifth aspect of the present invention is a water purification device that incorporates at least a polymer matrix of the present invention. Said device could for example a jug for water purification or a ion exchange column.

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Strategy TO

Preparation of neutral polymer matrices

Preparation of homogeneous polymer matrices . These polymeric matrices are obtained through the cross-linking of the polysaccharide (starch, dextrin, inulin, etc.) or cycloomaltooligosaccharides (α, β or γ-CD, 6-per-O-alkylcyclodextrins, per-2,3-di -O-alkylcyclodextrins) in an aqueous medium at basic pH (preferably in the range pH = 10-12) using different polysaccharide ratios: crosslinking agent and the latter being DVS or a bis-vinylsulfone of general formula H 2 C = CHSO 2 RSO 2 CH = CH 2 or H 2 C = CHSO 2 CH 2 CH 2 XRXCH 2 CH 2 SO 2 CH 2 CH 2 where R is a (C 1 -C 10) alkyl, a dialkylaryl ((C 1 -C 10) Ar (C 1 -C 10) or (CH 2) CH 2 O) n CH 2 CH 2 with n = 2-20; where X is
O or S.

In a preferred embodiment of the present invention has been used as polysaccharide starch, dextrin and inulin and cycloomaltooligosaccharides? and β-CD, as the cross-linking agent DVS and a ratio of 1 mole of crosslinking agent per mole of sugar.

Preparation of heterogeneous polymeric matrices . These polymeric matrices are obtained through the cross-linking of mixtures of a polysaccharide (starch, dextrin, dextran or inulin) and a cycloomaltooligosaccharide (α, β or γ-CD, 6-per-O-alkylcyclodextrins, per-2, 3-di-O-alkylcyclodextrins) in different polysaccharide proportions: oligosaccharide in an aqueous medium at basic pH (preferably in the range pH = 10-12) using different polysaccharide proportions: crosslinking agent and the latter being DVS or a bis-vinylsulfone of general formula H 2 C = CHSO 2 RSO 2 CH = CH 2 or H 2 C = CHSO 2 CH 2 CH 2 XRXCH 2 CH 2 SO 2 CH = CH 2 where R is a (C 1 -C 10) alkyl, a dialkylaryl ((C 1 -C 10) Ar (C 1 -C_ { 10}) or (CH 2 CH 2 O) n CH 2 CH 2 with n = 2-20; where X is O or S.

In a preferred embodiment of the present invention has been used as polysaccharide starch and as α and β-CD oligosaccharides in a 1: 1 ratio by weight, as the cross-linking agent the DVS and a ratio of 1 mole of crosslinking agent per mole of sugar.

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Strategy B

Preparation of polymeric matrices with load

In order to obtain polymeric matrices with ability to carry out metal or other decontamination type of compounds with loading incorporation of Load these matrices. To obtain these matrices loaded polymeric cross-linking of the polysaccharide (starch or dextrin) or cycloomaltooligosaccharide α, β or γ-CD) in an aqueous medium at basic pH (preferably in the range pH = 10-12) using different polysaccharide proportions: crosslinking and being the latter DVS or a bis-vinyl sulfone of general formula H 2 C = CHSO 2 RSO 2 CH = CH 2 or H 2 C = CHSO 2 CH 2 CH 2 XRXCH 2 CH 2 SO 2 CH = CH 2 where R is a (C 1 -C 10) alkyl, a dialkylaryl ((C_ {1} -C_ {10}) Ar (C_ {1} -C_ {10}) or (CH 2 CH 2 O) n CH 2 CH 2 with n = 2-20; where X is O or S and in the presence of different proportions of derivatives containing carboxylic acids such as H 2 N (CH 2) n COOH (n = 1-4), HS (CH 2) n COOH (n = 1-3) or HN [(CH 2) n COOH] 2 (n = 1-3) or amino groups, such as, HOCH 2 CH 2 N (CH 3) 3, HN [CH 2 CH 2 CH 2 NMe 2] 2 or HN [(CH 2) n Py] 2 (n = 0-1) (Py = 2-pyridyl).

In a preferred embodiment of the present invention has been used as polysaccharides starch and dextrin, as a crosslinking agent the DVS in a proportion of 1 mol of crosslinking agent per mole of sugar and as compounds loaded, glycine, 4-aminobutyric acid GABA, thioglycolic acid, iminodiacetic acid and choline in a proportion of 1 mol of compound with load per mol of DVS.

In a preferred embodiment of the present invention the study of the sequestering capacity of materials obtained is carried out in "batch" using solutions Aqueous of the selected pollutants or McOH mixtures: H2O in cases where they are not totally soluble. In all the case the influence of time and the concentration of contaminant on adsorption capacity and in the case of Heavy metals also make a study based on time. In the latter case, in addition, the regeneration capacity is studied of the material through a series of column studies.

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Definitions

Polymeric matrix in the context of this invention relates to crosslinked solid compositions of a natural or synthetic oligomer or polymer obtained by covalent crosslinking by reaction of multiple groups functional containing these polymers with an agent of cross-linking containing multiple functional groups with complementary reactivity to those of oligomers or polymers and that They are characterized by high rigidity and stability dimensional in its fabric when they are in contact with a aqueous or organic solvent and because they are insoluble in solvents aqueous.

Polymeric matrix with charge in the context of the The present invention relates to polymeric matrices as defined above that contain groups in their structure functional covalently bonded with electrostatic charges positive and / or negative.

Water treatment in the context of the The present invention refers to the processes involved in the elimination or reduction of contaminants present in water, especially wastewater. These pollutants can be from diverse nature: organic compounds, with or without charge, or compounds of inorganic nature. Neutral organics can be phenol and its derivatives, steroids, such as the progesterone. Compounds of inorganic nature may be heavy metal ions, such as chromium, cadmium and lead.

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Description of the figures

Figure 1. Effect of pH on the ability to adsorption of Cr 3+, Cd 2+ and Pb 2+ from the matrices Polymers containing carboxyl groups.

Figure 2. Evolution of the metal concentration in solution as a function of time for the matrices studied.

Figure 3. Comparison of the capacities of adsorption (in mg of metal / g of polymer) of Cr 3+, Pb 2+ and Cd2 +, for the polymeric starch matrix pA and the matrices polymers with carboxyl groups, obtained from 40 mL treatment of a 50 ppm metal solution with 50 mg of polymer.

Figure 4. Comparison of the capacities of adsorption (in mg dye / g polymer) of the dye, to the polymeric matrices pA, pACOL and pDCOL, to different initial concentrations.

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Modes of realization

The invention will be illustrated below through tests carried out by the inventors, which put manifest the ability of the new polymer based matrices in polysaccharides in the elimination of organic pollutants and inorganic

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Example 1 Preparation of neutral homogeneous polymer matrices

General procedure of synthesis of homopolymers derived from starch (pA), dextrins (pD) and cyclodextrins (p? CD and p? CD).

A solution of 3 g of the corresponding polysaccharide or cycloomaltooligosaccharide in 150 mL buffer (pH = 10-12) was kept under stirring for 5-20. Then 2 mL of divinyl sulfone (DVS) and the reaction mixture was maintained at room temperature for 7-8 hours. Solid appearing within the reaction was filtered under vacuum, washed with water to neutral pH and then with MeOH and with ether. Finally it was dried in the oven under vacuum and at 50 ° C for at least one night.

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Example 2 Preparation of heterogeneous neutral polymer matrices

General procedure for the synthesis of mixed polymers pA? CD and pA? CD.

A suspension of 1.5 g of starch in 150 mL of buffer (pH = 10-12) was heated to reflux until achieve complete solubilization of starch (15-20 minutes). Once dissolved it was allowed to the room temperature was reached and 1.5 g of CD was added (? or?). After 30 minutes, 2 were added mL of DVS. The resulting solution was kept under stirring at room temperature for 7-8 hours. Polymer filtered under vacuum, washed with water until neutral pH and at then with MeOH and with ether. Finally it dried on the stove vacuum and at 50 ° C for at least one night.

TABLE 1 Quantities of polysaccharide and DVS used in the preparation of the different polymers and amount of polymer obtained

one

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Example 3 Preparation of polymeric matrices with load

General procedure for the synthesis of polymers PAGABA, PAGLY, PATA, PAIDA.

A suspension of 3 g of starch in 150 mL of buffer (pH = 10-12) was heated to reflux (15-20 minutes). Once dissolved it was allowed to the room temperature was reached and 2 mL of DVS was added. The resulting solution was kept under stirring for 30 minutes. the corresponding carboxylic acid was added. Passed 7-8 hours the polymer was filtered under vacuum, washed with water to neutral pH and then with MeOH and with ether. By the latter was dried in the oven under vacuum and at 50 ° C for at least one night.

In all cases the acid is used corresponding, except in the case of thioacetic acid that use the sodium salt thereof.

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TABLE 2 Reagents and quantities used in the synthesis of anionic starch polymers and amount of polymer obtained

2

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Example 4 Preparation of polymeric matrices with load

General procedure for the synthesis of polymers pDTA and pDIDA.

A solution of 3 g of dextrin in 150 mL of buffer (pH = 10-12) was kept under stirring at room temperature for 30 minutes and then you added 2 mL of DVS. After 30 minutes the acid was added corresponding carboxylic. After 7-8 hours The polymer was filtered under vacuum, washed with water until neutral pH and at  then with MeOH and with ether. Finally it dried on the stove vacuum and at 50 ° C for at least one night.

TABLE 3 Reagents and quantities used in the synthesis of anionic dextrin polymers and amount of polymer obtained

3

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Example 5 Preparation of polymeric matrices with load

General procedure for the synthesis of pACOL and pDCOL polymers.

For the synthesis of these polymers, it was used the same methodology as used for anionic polymers of starch and dextrin, but instead of adding acid corresponding choline was used. The amounts with which worked and the amount of polymer obtained are listed in the table Four.

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TABLE 4 Reagents and quantities used in the synthesis of polymers containing quaternary amines and amount of polymer obtained

4

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Example 6 Adsorption studies of neutral organic compounds

To carry out this study have been used a series of model aromatic compounds, specifically phenol, the 4-nitrophenol, β-naphthol and  bisphenol-A considered contaminants.

At 100 mg of polymer (pA, p? CD, pαCD, pAβCD and pAαCD) are added 10 mL of the solute solution and the resulting suspension is kept under orbital agitation at 180 rpm for 2-3 hours and at room temperature. Then both the treated solution with the polymer as the starting solution are filtered using a regenerated cellulose syringe filter and the concentration is measured by UV-Vis absorption.

TABLE 5 Conditions used in the studies of adsorption

5

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For the different matrices used and the different compounds used the results obtained are summarized in the following tables.

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TABLE 6 Adsorption capacities (in mg of contaminant / g of polymer) of phenol for neutral to different polymeric matrices initial concentrations of phenol (2.5 hours of stirring at room temperature)

6

TABLE 7 Adsorption capacities (in mg of contaminant / g polymer) 4-nitrophenol for the matrices neutral polymers at different initial concentrations of 4-nitrophenol (2.5 hours of stirring at temperature ambient)

7

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TABLE 8 Adsorption capacities (in mg of contaminant / g of polymer) of β-naphthol in Water-MeOH (10%) for polymeric matrices neutral at different initial concentrations of β-naphthol (2.5 hours stirring at room temperature)

8

TABLE 9 Adsorption capacities (in mg of contaminant / g of polymer) of bisphenol-A in water-MeOH (10%) for neutral to different polymer matrices initial concentrations of bisphenol A (2.5 hours of stirring at room temperature)

9

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Example 7 Study of the influence of pH on metal adsorption heavy

Three polluting model metals of waters, Cr 3+, Pb 2+ and Cd 2+. To study the influence of pH on the capacity of polymeric matrices with carboxyl groups to retain heavy metals a 50 ppm solution of each of the metals to be studied (Cr 3+, Cd 2+ + and Pb 2+). In all cases this initial solution has a pH around 2 that is modified by adding a 10% NaOH solution. If from Cr 3+ and Cd 2+ solutions at pH 2, 3, 4, 5 and 6. In the case of Pb 2+ at pH 2, 3, 4 and 5. At 50 mg of polymer (pAGABA for Cr 3+ and Pb 2+ and pAGly for Cd 2+) 20 mL of each of the solutions was added previous. The resulting suspension was kept under stirring. orbital at 180 rpm for 1 night. The solution was centrifuged and they took 3 mL of the supernatant. The concentration of metal in solution, both of the starting samples and those treated with the Polymer is determined by atomic absorption.

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Example 8 Study of the influence of time on metal adsorption heavy

Three polluting model metals of waters, Cr 3+, Pb 2+ and Cd 2+. To study the time needed to achieve balance is prepared a 50 ppm solution of each of the metals to be studied (Cr 3+, Cd 2+ and Pb 2+) and adjust to the optimum pH of work, pH 6 for Cr 3+ and Cd 2+ and pH 5 for Pb 2+. Be 75 mg of each of the polymers with which they work and weigh 40 mL of the metal solution is added. The suspension resulting is kept under orbital agitation at 180 rpm and each certain time (5, 15, 30, 60, 120, 240, 360 and 1020 minutes) is taken an aliquot (1.5-2 mL) to measure your concentration. In the case of Cr 3+ and Pb 2+ work with the polymers pAGABA, pAGly and pATA and in the case of Cd2 + the polymers pAGly, pATA and pAIDA are used. As in the pH-based study the concentration of metal in solution is determined by atomic absorption.

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Example 9 Study of the adsorption capacity of heavy metals

At 50 mg of each of the polymers (pA, PAGABA, PAGLY, PATA, PDTA, PAIDA and PIDIDA) 40 mL of a 50 ppm metal solution at pH 6 for Cr 3+ and Cd 2+ and pH 5 for Pb 2+. The resulting suspension is kept low orbital agitation at 180 rpm overnight at temperature ambient. The samples are centrifuged and 3 mL of the supernatant The initial metal concentration and what remains in Solution are determined by atomic absorption.

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Example 10 Adsorption and desorption column studies

To study the possible reuse of these materials adsorption and desorption studies were carried out in column.

Chromium : 200 mg of the pAIDA polymer is suspended in water and packed, with the help of a peristaltic pump, in a 2.5 mL syringe fitted with a filter. Once the column is assembled, 50 mL of 0.5M carbonate buffer pH 12 is passed to activate the carboxyl groups, and then 50 mL of water. Once the column is assembled and activated, 150 mL of a Cr3 + solution of 50 ppm is passed at pH 6 at a flow rate of 1.5 mL / min. The column is then washed with 20 mL of 5% HCl to desorb the retained metal, collecting this wash solution in 5 mL aliquots. It is then washed with 45 mL of water, 45 mL of 0.5M carbonate buffer pH 12 and finally with another 45 mL of water. Again 150 mL of a 50 ppm Cr 3+ solution is passed at pH 6 at the same flow rate, ie 1.5 mL / min. The column is washed again and regenerated exactly the same as the previous time but instead of washing with 5% HCl a solution of 3% HNO 3 is used. Finally, a solution (150 mL) of Cr 3+ at pH 6 is circulated again through the column. The concentration of Cr 2+ in each of the solutions, including the starting solutions , is determined by atomic absorption.

Cadmium : The study is carried out exactly the same as in the case of Cr 3+ but, instead of using the pAIDA polymer, the pDIDA polymer is used.

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TABLE 10 Results of adsorption and desorption studies in column for Cr 2+ (pAIDA) and Cd 2+ (ORDER)

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Lead : In the case of Pb 2+, the same procedure used in the case of Cr 3+ and Cd 2+ is followed with some differences listed below:

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150 mg of the polymer ORDER.

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Through the column you 190 mL of a 50 ppm Pb2 + solution is passed at pH 5.

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In this case all washes they are carried out with 3% HNO 3.

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The column was reused a 6 times total.

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TABLE 11 Results of adsorption and desorption studies in column for Pb2 + (loss)

eleven

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Example 11 Adsorption studies of charged organic compounds

To study the capacity of the matrices polymeric containing amino groups in the elimination compounds with anionic groups the dye shown to is used which then contains a sulfonic group.

12

At 100 mg of polymer matrix (pA, pACOL and pDCOL) 10 mL of the solute solution and the resulting suspension is maintained under orbital agitation at 180 rpm for 2-3 hours and at room temperature. TO then, both the solution treated with the polymer and the Starting solution is filtered using a syringe filter regenerated cellulose and the concentration is measured by absorption UV-Vis.

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TABLE 12 Conditions used in the studies of adsorption

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The results are shown in the following table and the following graphic.

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TABLE 13 Adsorption capacities (in mg dye / g of polymer) of the dye in water at different concentrations initial dyes (3 hours of stirring at 22ºC)

14

Claims (40)

1. The use for the treatment of water of a polymeric matrix characterized in that it comprises units of polysaccharides cross-linked with unsaturated α-β sulfones. 2. The use of the polymeric matrix according to claim 1, characterized in that the unsaturated α-β-sulfone is preferably a bis-vinylsulfone, preferably selected from H 2 C = CHSO 2 CH = CH 2 }, H2 C = CHSO2
RSO 2 CH = CH 2, H 2 C = CHSO 2 CH 2 CH 2 XRXCH 2 CH 2 SO 2 CH = CH 2 where R is a (C 1 -C 10) alkyl, a dialkylaryl ((C 1 -C 10) Ar (C 1 -C 10), (CH 2 CH 2) O) n CH2CH2 with n = 2-20; where X is O or S, and mixtures thereof. 3. The use of the polymeric matrix according to claim 2, characterized in that the bis-vinylsulfone is divinylsulfone. 4. The use of the polymeric matrix according to any of the preceding claims, characterized in that the polymeric matrix comprises at least one polysaccharide selected from, starch, modified starch, cyclodextrins, modified cyclodextrins, chitosan, cellulose, dextran, inulin, amylose, amylopectin, dextrin and mixtures thereof. 5. The use of the polymeric matrix according to claim 4, characterized in that the polymeric matrix comprises starch, dextrin or mixtures thereof. 6. The use of the polymeric matrix according to claim 4, characterized in that the polymeric matrix comprises at least one cyclodextrin, preferably α, β, γ-cyclodextrins or mixtures thereof. 7. The use of the polymeric matrix according to claim 4, characterized in that the polymeric matrix comprises at least two polysaccharides 8. The use of the polymeric matrix according to claim 7, characterized in that the polymeric matrix comprises at least starch and cyclodextrin. 9. The use of the polymeric matrix according to claim 8, characterized in that the polymeric matrix comprises at least one cyclodextrin selected from α, β, γ and mixtures thereof. 10. The use of the polymeric matrix according to any of the preceding claims, characterized in that the polymeric matrix incorporates charge. 11. The use of the polymeric matrix according to any of the preceding claims, characterized in that the polymeric matrix comprises derivatives selected from the list comprising derivatives having carboxylic acids, sulfonic acids, amino groups or mixtures thereof. 12. The use of the polymeric matrix according to claim 11, characterized in that the polymeric matrix comprises derivatives selected from the list comprising H2N (CH2) nCOOH (where n = 1- 20), HS (CH 2) n COOH (where n = 1-20), HN [(CH 2) n COOH] 2 (n = 1-3), HOCH 2 CH 2 N (CH 3) 3, HN [CH 2 CH 2 CH 2 NMe 2] 2, HN [(CH 2 ) n Py] 2 (where n = 0-1 and Py = 2-pyridyl) and mixtures thereof. 13. The use of the polymeric matrix according to any of claims 10 to 12, characterized in that the polymeric matrix comprises between 50 to 800 microequivalents of acid or base per gram of polymeric matrix. 14. The use of the polymeric matrix according to any of claims 10 to 12, characterized in that the polymeric matrix comprises:

to)

A polysaccharide selected from starch, dextrin, cyclodextrins and mixtures thereof;

b)

At least one bis-vinyl sulfone, preferably divinylsulfone

C)

At least one derivative of a carboxylic acid or a derived from an amino group selected from the list comprising H 2 N (CH 2) n COOH (being n = 1-20), HS (CH 2) n COOH (where n = 1-20), HN [(CH 2) n COOH] 2 (n = 1-3), HOCH 2 CH 2 N (CH 3) 3, HN [CH 2 CH 2 CH 2 NMe 2] 2, HN [(CH 2) n Py] 2 (being n = 0-1 and Py = 2-pyridyl) and mixtures of they.

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15. The use of the polymeric matrix according to claim 14, characterized in that it comprises at least starch and a cyclodextrin. 16. The use of defined polymer matrices in any of claims 1 to 15 for the reduction or pollutant removal 17. The use of defined polymer matrices in any of claims 1 to 15 for purification of water. 18. The use of defined polymer matrices in any of claims 1 to 15 for adsorption of neutral organic compounds 19. The use of defined polymer matrices in any of claims 1 to 15 for the reduction or elimination of neutral organic compounds present in water. 20. The use of loaded polymeric matrices defined in any of claims 10 to 15 for the adsorption, reduction or elimination of ions. 21. A polymer matrix characterized in that it comprises units of cross-linked polysaccharides with at least one unsaturated α-β sulfone. 22. The polymer matrix according to claim 21, characterized in that the unsaturated α-β-sulfone is a vinyl sulfone. 23. The polymer matrix according to claim 22, characterized in that the bis-vinylsulfone is divinylsulfone. 24. The polymer matrix according to any of claims 21 and 22, characterized in that it comprises at least one polysaccharide selected from, starch, modified starch, cyclodextrins, modified cyclodextrins, chitosan, cellulose, dextran, inulin, amylose, amylopectin, dextrin and mixtures of them. 25. The polymer matrix according to claim 24, characterized in that it comprises starch, dextrin or mixtures thereof. 26. The polymer matrix according to claim 24, characterized in that it comprises at least one cyclodextrin. 27. The polymeric matrix according to claim 24, characterized in that it comprises at least two polysaccharides. 28. The polymer matrix according to claim 27, characterized in that it comprises at least one starch and a cyclodextrin. 29. The polymer matrix according to claim 28, characterized in that it comprises at least one cyclodextrin selected from?,?,? And mixtures thereof. 30. The polymeric matrix according to any of claims 21 to 29, characterized by the incorporation of charge. 31. The polymeric matrix according to any one of claims 21 to 30, characterized in that it comprises derivatives selected from the list comprising derivatives possessing carboxylic acids, sulphonic acids, amino groups and mixtures thereof. 32. The polymer matrix according to claim 31, characterized in that it comprises derivatives selected from the list comprising H 2 N (CH 2) n COOH (where n = 1-20), HS (CH_ {2) n COOH (where n = 1-20), HN [(CH2) n
COOH] 2 (n = 1-3), HOCH 2 CH 2 N (CH 3) 3, HN [CH 2 CH 2 CH 2 NMe_ { 2] 2, HN [(CH 2) n Py] 2 (where n = 0-1 and Py = 2-pyridyl) and mixtures thereof. 33. The polymer matrix according to any one of claims 30 to 32, characterized in that it comprises between 50 to 800 microequivalents of acid or base per gram of polymer matrix. 34. The polymeric matrix according to any of claims 30 to 32, characterized in that it comprises:

to)

A polysaccharide selected from starch, dextrin, cyclodextrins and mixtures thereof;

b)

At least one bis-vinyl sulfone

C)

A derivative of a carboxylic acid or a group amino selected from the list comprising H 2 N (CH 2) n COOH (being n = 1-20), HS (CH 2) n COOH (where n = 1-20), HN [(CH 2) n COOH] 2 (n = 1-3), HOCH 2 CH 2 N (CH 3) 3, HN [CH 2 CH 2 CH 2 NMe 2] 2, HN [(CH 2) n Py] 2 (being n = 0-1 and Py = 2-pyridyl) and mixtures of they.

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35. The polymer matrix according to claim 34, characterized in that it comprises at least starch and a cyclodextrin. 36. A process for the synthesis of a polymeric matrices as defined in any of claims 21 to 35 characterized in that it comprises at least the following steps:

i)

the polysaccharide or polysaccharides dissolve, preferably in buffer pH = 10-12, and heating if It was necessary.

ii)

agent is added cross-linking

iii)

the resulting mixture is kept low agitation.

iv)

the polymer is filtered and washed resulting

v)

if required, the polymer is dried.

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37. The process for the synthesis of a polymer matrix with a charge comprising the steps of claim 36, characterized in that after step ii) the agent responsible for the incorporation of the charge is added. 38. The process for the synthesis of a polymer matrix with charge according to claim 37, characterized in that the charge incorporating agent is selected from the list comprising derivatives of carboxylic acids, derivatives of amino groups and mixtures thereof. 39. The process for the synthesis of a polymer matrix with charge according to claim 38, characterized in that the charge incorporating agent is selected from the list comprising H 2 N (CH 2) n COOH (where n = 1-20), HS (CH 2) n COOH (where n = 1-20), HN [(CH 2) n COOH] 2 (n = 1-3), HOCH 2 CH 2 N (CH 3) 3, HN [CH 2 CH 2 CH 2]
NMe 2] 2, HN [(CH 2) n Py] 2 (where n = 0-1 and Py = 2-pyridyl) and mixtures thereof. 40. A device for water purification that includes at least one polymer matrix as defined in any of claims 21 to 35.