CN1886189A - Synthesis of ion imprinted polymer particles - Google Patents

Abstract

Ion-imprinted polymer materials containing metal ion recognition sites are synthesized. These particles are synthesized by copolymerizing functional monomers and crosslinking monomers in the presence of at least one imprinted metal ion in the form of a ternary complex. Polymerization is carried out by gamma irradiation (without an initiator) or photochemical polymerization and thermal polymerization (with an initiator, AIBN). After drying, these materials are ground and sieved to obtain erbium ion-imprinted polymer particles. The erbium ions are removed from the polymer particles by inorganic acid leaching, leaving cavities/binding sites within the polymer particles. The resulting polymer particles can be used as solid-phase extractants for selectively enriching erbium ions from dilute aqueous solutions.

Description

Synthesis of Ionically Imprinted Polymer Particles

field of invention

The present invention relates to the synthesis and method of ion-imprinted polymer particles for solid-phase extraction of pre-concentrated erbium ions. Ionically imprinted polymer particles are prepared by radiochemical polymerization, photochemical polymerization and thermal polymerization.

Background of the invention

Monazite is processed through a range of beneficiation methods to produce light, moderate and heavy rare earth chloride fractions. The last part contains _55-60 % _Y2O3 and impurities Dy, Gd and Er. The importance of preparing 99.9-99.999% Y ₂ O ₃ is that it is widely used in the manufacture of lasers, superconducting materials, and color TV phosphors. Therefore, the separation of Dy, Gd and Er becomes an essential prerequisite for _the preparation of such high-purity _Y2O3 . Three different polymerization processes described _in this patent can achieve the separation of erbium from _Y2O3 .

enantiomeric resolution

Referring to patent application WO 98/07671; 1998, Mark et al. prepared imprinted polymers for the separation of optically active compounds ibuprofen, naproxen and ketoprofen into their respective enantiomers. Referring to U.S. Patent No. 6,316,235; 2001, Mosbach et al. by copolymerizing one or more functional monomers and crosslinking monomers in the presence of at least one imprinting molecule and at least one magnetically sensitive component, such as iron oxide or nickel oxide to prepare magnetically sensitive components. Imprinted molecules are subsequently removed, forming molecular memory recognition sites. These particles are used for the selective separation of two different enantiomeric forms. Also refer to U.S. Patent No. 5,786,427; 1998, Arnold et al. prepared solid phase extraction materials comprising a polymer matrix containing one or more metal complexes by molecular imprinting, which can selectively bind only optically active amino acids or peptides An enantiomer. Referring to US Patent No. 5,461,175; 1995, Fischer et al. synthesized a chiral chromatography material for the separation of enantiomers of aryloxypropanolamine derivatives.

sensor

Referring to U.S. Patent No. 6,063,637; 2000, Arnold et al. developed sensors consisting of metal complexes that can bind target molecules and release protons, or that contain exchangeable The target molecule is exchanged during the binding process of the substance and the target molecule. These sensors are used to detect the presence of sugars and other metal-bound analytes. Referring to U.S. Pat. No. 5,587,273; 1996, Yan et al. prepared molecularly imprinted substrates and sensors by first forming a solution comprising a solvent and (a) a polymeric material capable of addition reaction with a nitrene, (b) a cross-linked agents, (c) functional monomers and (d) imprinted molecules. Other Applications of Molecular Imprinting

Referring to US Patent No. 6,310,110; 2001, Markowitz et al. synthesize molecularly imprinted porous structures from assembled surfactant analogs to generate at least one supramolecular structure containing exposed imprinted groups. Imprinted porous structures are formed by adding reactive monomers to the mixture and allowing these monomers to polymerize with templated supramolecular structures. Referring to US Patent No. 6,057,377; 2000, Sasaki et al. developed a method for forming molecularly imprinted metal oxide sol-gel materials by molecularly imprinting onto the surface of the sol-gel material, solvents, and imprinted molecules. Referring to US Patent No. 6,255,461; 2003, Mosbach and Olof prepared artificial antibodies by molecular imprinting, in which methacrylic acid, ethylene glycol dimethacrylate, and corticosteroid imprinted molecules were combined to form artificial antibodies. These antibodies can be used in isolation and analysis processes. References US Patent Application No. 2003-049970, 2003, Magnus et al. prepared selective adsorption materials useful for purification or analysis of biomacromolecules.

Ion Blotting - Anions

Referring to US Patent Application No. 2003-113234, in 2003, Murray prepared a molecularly imprinted polymer membrane for selectively collecting phosphate, nitrate and iron ions. These membranes are prepared by copolymerization of matrix monomers, crosslinking monomers, ion imprinting complexes, osmotic agents, and polymerization initiators, followed by removal of ions and osmotic agents from the ion imprinting complexes. The osmotic agent creates channels in the membrane that allow the membrane to communicate with the outer surface of the ion binding site in the membrane. In US Patent Application No. 2003-059346, 2003, Murray mentioned the use of permselective polymer membranes to remove phosphate, nitrate. Preparation of selective binding sites by ferric ion blotting. Permeability is enhanced by the use of polyesters bound to metal ions; and the polyesters are removed from the membrane by the same acid treatment used to remove iron ions. The polyester creates channels that guide the movement of ions towards the imprinted site, thus increasing flux and maintaining selectivity.

Ion Blot - Cation

Referring to US Patent No. 6,248,842; 2001, Singh et al. produced selectively crosslinked chelating polymers by substituting polymerizable functional groups for aliphatic chelating agents. The resulting substituted aliphatic chelating agent is then subjected to a coordination reaction with a target metal ion, such as copper. Then add a cross-linkable monomer to react with the complex material for cross-linking. The coordinated metal ions are removed, resulting in a cross-linked polymeric chelating agent templated by the target metal ion. Reference Patent Application No. WO99/15707; 1999, John et al. detected and extracted uranyl ions by polymer imprinting, wherein the coordination function was the molecular formula CTCOOH, its methyl and halogen substituted form or COOH or PhCOOH, where T is hydrogen or any halogen (preferably chlorine). Gladis and Rao also proposed the synthesis of ion-imprinted polymers for solid-phase extraction preconcentration/separation of uranyl ions from a host of tetravalent, trivalent, and divalent inorganic ions in seawater and artificial seawater. Synthesis of imprinted ion with 8-hydroxyquinoline (quinoline-8-ol) or its dihalogenated derivatives and 4-vinylpyridine in the presence of styrene and divinylbenzene as functional monomers and crosslinking monomers ternary mixed ligand complexes. Referring to US Patent No. 6,251,280, 2001, Dai et al. used ion imprinting technology to separate inorganic substances using bifunctional ligands such as amines, thiols, carboxylic acids, sulfonic acids, and phosphoric acids to prepare mesoporous adsorbent materials. The carboxylic acid groups on the bifunctional ligands are used in the formation of mesoporous sorbent materials specific for erbium template ions.

Rao et al [see Trends in Anal. Chem.; 2003] reviewed the preparation of adapted materials for preconcentration/separation of metals by ion-imprinted polymers (IIP-SPE) for solid phase extraction. The ion-imprinted polymer (IIP) material with nanopores is formed by forming a ternary complex of palladium imprinted ions and dimethylglyoxime and 4-vinylpyridine, and in 2,2'-azobisisobutyronitrile In the presence of cyclohexanol as a porogen, it is prepared by thermal copolymerization with styrene and divinylbenzene [see Sobhi et al., Anal.Chim.Acta, 488 (2003) 173-182]. Cationic imprinted SPE materials based on diethylenetriaminepentaacetic acid (DTPA) derivatives have been prepared for the separation of La and Gd. Imprinting effects were observed for materials prepared in the presence of Gd salts and showed high efficiency and high selectivity compared to the corresponding blank polymer [see Garcia et al., Tetrahedron Lett., 39 (1998) 8651]. The functionalized monomer of DTPA was copolymerized with commercially available divinylbenzene containing 45% ethylstyrene in the presence of Gd ³⁺ salt. The resulting IIP was found to be more selective for Gd than for La [see Vigneau et al., Anal. Chim. Acta, 435 (2001) 75]. These selectivity studies were also extended to the determination of _SGd/Eu and _SGd/Lu using Gd imprinted IIP [see Logneau et al., Chem. Lett. (2002) 202]. Biju et al. [see Anal. Chim. Acta, 478 (2003) 43-51] synthesized Dy(III) IIP particles by copolymerizing styrene (functional monomer) in the presence of DVB as a crosslinking monomer. Some authors [see Talanta, 60 (2003) 747-754] also reported improved Dy selectivity coefficients for La, Nd, Y and Lu after gamma-irradiation of Dy IIP particles.

The prepared molecularly imprinted polymer particles are widely used in the separation of enantiomers, structurally related drugs, amino acid derivatives, nucleotide base derivatives, etc. Therefore it is widely used in chemical and pharmaceutical industries, water purification and waste disposal. On the other hand, the preparation of ionically imprinted polymer particles is not commonly used for the separation of closely associated inorganic ions. Only in US Patent No. 6,251,280; 2001, Dai et al. addressed this issue, but in a general way and did not deal with the separation of erbium from the closely associated lanthanum.

purpose of invention

The main objective of this study is to prepare Erbium IIP materials by gamma-irradiation in the presence of different contents of methyl methacrylate (MMA) (functional monomer).

Another object of the present invention is to provide a method for preparing Erbium IIP materials by photochemical polymerization as a function of exposure time.

Another object of the present invention is to provide a process for the preparation of Erbium IIP materials by thermal polymerization as a function of EGDMA (crosslinking monomer) concentration.

Another object of the present invention is to use IIP particles to preconcentrate and separate erbium from other selected lanthanums by solid phase extraction.

Summary of the invention

Accordingly, the present invention provides a method for the synthesis of ion-imprinted polymer particles for solid phase extraction of pre-concentrated erbium ions, the method comprising:

(a) Erbium ions form mixed ligand ternary complexes with 5,7-dichloro-8-hydroxyquinoline (5,7-dichloroquinoline-8-ol) and 4-vinylpyridine;

(b) Dissolving the ternary complex in a suitable porogen to form a pre-polymerization mixture.

(c) combining the mixture in step (b) with functional monomers and cross-linking monomers, and carrying out polymerization reactions by gamma-radiation or photochemical polymerization and thermal polymerization to obtain polymer materials;

(d) Grinding and sieving the polymer material obtained in step (c) to prepare erbium ion-imprinted polymer particles;

(e) selectively leaching the imprinted ion-intercalated material in the polymer particles of step (d) with a mineral acid.

In one embodiment of the invention, the gamma-irradiation is performed as a function of the concentration of methyl methacrylate (functional monomer).

In another embodiment of the present invention, said photochemical polymerisation is performed as a function of UV radiation time.

In another embodiment of the present invention, said thermal polymerisation is carried out as a function of the concentration of ethylene glycol dimethacrylate (crosslinking monomer).

In another embodiment of the present invention, the functional monomer is selected from 4-vinylpyridine and methyl methacrylate.

In another embodiment of the present invention, the crosslinking monomer comprises ethylene glycol dimethacrylate.

In another embodiment of the present invention, the reaction is carried out using 2,2'-azobisisobutyronitrile as initiator in step (c).

In another embodiment of the present invention, the pulverization and sieving in step (d) are performed after drying of the erbium ion imprinted polymer material.

In another embodiment of the invention, the mineral acid used for leaching comprises HCl.

Brief description of the drawings

In the drawings attached to this manual:

Figure 1 shows 5,7-dichloro-8-hydroxyquinoline (DCQ), 4-vinylpyridine (VP), DCQ+VP, Er ³⁺ +DCQ+Er, Er ³⁺ +VP and Er ³⁺ + UV-Vis absorption spectrum of DCQ+VP.

Figure 2 is a schematic diagram of the formation of a ternary mixed-ligand complex.

Figure 3 is a schematic diagram of the polymer imprinting process.

Figure 4 shows the effect of methyl methacrylate (MMA) (functional monomer) concentration on Er ³⁺ preconcentration using IIP particles synthesized by gamma-irradiation.

Figure 5 shows the effect of UV-irradiation time on Er ³⁺ preconcentration using IIP particles synthesized by photochemical polymerization.

Figure 6 shows the effect of ethylene glycol dimethacrylate (EGDMA) (crosslinking monomer) concentration on Er ³⁺ preconcentration using IIP particles synthesized by thermal polymerization.

Detailed Description of the Invention

The present invention provides a method for the synthesis of selectively erbium ion imprinted polymer particles with accessible and homogeneous imprinted sites for solid phase extraction from dilute aqueous solutions.

As used herein, the term "ion-imprinted polymer (IIP)" refers to a material polymerized around imprinted ions in such a way that when imprinted ions are removed from the material, cavities or "imprinted sites" remain in contact with the imprinted ions. In materials of complementary shapes and sizes. The IIP material is added to a diluent containing imprinted ions, and the imprinted sites selectively bind to the imprinted ions. This combination allows the aforementioned adapted materials to be used to enrich/separate imprinted ions from other similar ions. Salient feature of the present invention comprises the following aspects:

i) Synthesis of adapted IIP particles via thermal polymerization, photochemical polymerization, and γ-radiation polymerization.

ii) Pretreating the polymer to leach the imprinted ions.

iii) Enrichment from dilute aqueous solutions.

i) Synthesis of Adapted Erbium IIP Materials

The synthesis of adapted erbium IIP materials involves two major steps: (I) formation of ternary mixed-ligand complexes with imprinted ions (erbium) and (II) polymerization of ternary mixed-ligand complexes with MMA and EGDMA. Ternary complex formation was carried out in 2-methoxyethanol (pore former). The complex formation process was monitored by recording UV-Vis spectra. Figure 1 shows 5,7-dichloro-8-hydroxyquinoline (DCQ), 4-vinylpyridine (VP), DCQ+VP, Er ³⁺ +DCQ+Er, Er ³⁺ +VP and Er ³⁺ + Absorption spectrum of DCQ+VP. These spectra clearly indicate the formation of the ternary complex in 2-methoxyethanol solution (see Figure 2).

Ternary complexes were imprinted by the addition of functional monomers (MMA) and cross-linking monomers (EGDMA). In thermal polymerization and photochemical polymerization, only 2,2'-azobisisobutyronitrile is added as a polymerization initiator. The obtained IIP material was dried in an oven at 50° C. to obtain an erbium ion IIP material. Figure 3 is a schematic diagram of the polymer imprinting process. These materials are ground and sieved to obtain erbium ion IIP particles. Figure 4, Figure 5 and Figure 6 show the effect of MMA concentration, UV-irradiation time and EGDMA concentration on Er ³⁺ enrichment using IIP synthesized by γ-radiation polymerization, photochemical polymerization and thermal polymerization, respectively.

ii) Pretreatment of IIP material to extract imprinted ions

The imprinted ion, Er3 ⁺ , was leached from the polymer by stirring with 5N HCl solution for 6 hours. The resulting IIP particles were dried in an oven at 50°C to obtain Erbium IIP-SPE particles, which were used to selectively enrich Erbium ions from dilute aqueous solutions.

iii) Enrichment of Er ³⁺ from dilute aqueous solution

The enrichment of erbium ions from dilute aqueous solutions with erbium IIP particles was studied in detail. Figure 4 shows the effect of methyl methacrylate (MMA) concentration on the percent erbium ion enrichment of Er ³⁺ IIP polymerized using gamma-irradiation. Figure 5 shows the effect of UV-irradiation time on the percent erbium enrichment using IIP particles synthesized by photochemical polymerization. Figure 6 shows the effect of crosslinking monomer (EGDMA) concentration in the enrichment of erbium ions with IIP particles synthesized by thermal polymerization.

Therefore, the present invention provides "synthesis and method thereof for adapting to IIP-SPE particles for extracting erbium ions", which method comprises the following related steps:

(i) Preparation of IIP particles by γ-radiation polymerization, photochemical polymerization, and thermal polymerization.

(ii) Enrichment of erbium ions from dilute aqueous solutions.

(iii) Separation of erbium from other lanthanides.

The following examples describe the synthesis of ion-imprinted polymer materials for selective solid-phase extraction of erbium ions.

Example 1: Gamma-radiation polymerization

In a 50ml round bottom flask, 1.0mM Erbium chloride (0.44g), 3.0mM DCQ (0.64g) and 2mM VP (0.21g) were added and dissolved in 5 or 10ml 2-methoxyethanol with stirring. 4 (0.4g) or 8 (0.8g) and 12 (1.2g) mM MMA and 16 (3.17g) or 32 (6.34g) and 48 (9.52g) mM EGDMA were added and stirred until a homogeneous solution was obtained. The monomer mixture was transferred to a _test tube, cooled to 0 °C, purged with N for 10 min and sealed.

These solutions were irradiated for 4 hours under 1 M Rad radiation gamma-irradiation using a Co ⁶⁰ source. The solid formed was washed with water and dried in an oven at 50°C. 5.70, 9.43 and 14.27 g of polymeric material were obtained with 4, 8 and 12 mM functional monomer, respectively. The polymer intercalating the erbium ions was leached with 50% (v/v) HCl while stirring for 6 hours. After drying in an oven at 50°C, 4.14, 7.52 and 11.29 g of polymeric material were obtained with 4, 8 and 12 mM functional monomer, respectively.

Embodiment 2: photochemical method polymerization

In a 50ml round bottom flask, 1.0mM Erbium chloride (0.44g), 3.0mM DCQ (0.64g) and 2.0mM VP (0.21g) were added and dissolved in 10ml 2-methoxyethanol with stirring. 8mM MMA (0.8g), 32mM EGDMA (6.35g) and 50mg AIBN were added and stirred until a homogeneous solution was obtained. The monomer mixture was transferred to a _test tube, cooled to 0 °C, purged with N for 10 min and sealed. These solutions were polymerized by UV radiation (300 nm) for 4, 8 and 16 hours. The solid formed was washed with water and dried in an oven at 50°C. 7.55, 9.85 and 9.95 g of polymer material were obtained with UV radiation (300 nm) for 4, 8 and 16 h. The polymer intercalating the erbium ions was leached with 50% (v/v) HCl while stirring for 6 hours. After drying in an oven at 50° C., 5.35, 7.31 and 7.36 g of polymeric material were obtained after UV irradiation for 4, 8 and 16 h, respectively.

Example 3: thermal polymerization

In a 50ml round bottom flask, 1.0mM Erbium chloride (0.44g), 3.0mM DCQ (0.64g) and 2.0mM VP (0.21g) were added and dissolved in 10ml 2-methoxyethanol with stirring. 8.0 mM MMA (0.8 g), 8, 16 and 32 mM EGDMA (1.59, 3.17 and 6.34 g) and 50 mg AIBN were added and stirred until a homogeneous solution was obtained. The polymerization mixture was cooled to 0 °C, purged with _N2 for 10 min, sealed and heated and stirred in an oil bath at about 80 °C for 2 h. The solid formed was washed with water and dried in an oven at 50°C. 4.32, 5.50 and 8.84 g of polymer material were obtained with 50%, 66% and 80% crosslinking monomer. The polymer intercalated with erbium ions was extracted with 100 ml of 50% (v/v) HCl, stirred for 6 hours, filtered, and dried in an oven at 50°C. 2.59, 3.90 and 7.90 g of erbium ion imprinted polymer material were obtained.

Advantages of the present invention:

Liquid-liquid extraction methods have replaced conventional ion exchange methods due to their speed, reliability and ease of scale-up. However, since the separation coefficient of Er with respect to Y is close to 1.0, the liquid-liquid extraction method requires 40–50 steps of countercurrent extraction. Furthermore, the mandatory use of large quantities of toxic chemicals as solvents and extractants. On the other hand, the separation method described in this invention based on the addition of imprinted polymer particles is more environmentally friendly, which involves lower costs due to the use of less chemicals and provides better Er for Y, Dy, Gd, Tb, etc. selection coefficient.

references:

patent documents

WO9807671 Mark et al.

Separating enatiomers by molecular imprinting

US 6,316,235 Mosbach et al

Preparation and use of magnetically susceptible polymer particles

US 5,786,428 Arnold et al

Adsorbents for amino acids and peptide separation

US 5,461,175 Fischer et al.

Method for separating enantiomers of aryloxipropanolamine derivatives and chiral solid phase chromatography material for use in the method

US 6,063,637 Arnold et al

Sensors for sugars and other metal binding analytes (sensors for sugars and other metal binding analytes)

US 5,587,273 Yan et al

Molecularly imprinted materials, method for their preparation and devices employing such materials

US 6,310,110 Markowitz et al

Molecularly imprinted material made by template directed synthesis (molecularly imprinted material made by template directed synthesis)

US 6,057,377 Sasaki et al

Molecular receptors in metal oxide sol-gel materials (molecular receptors in metal oxide sol-gel materials)

US 6,255,461 Mosbach et al

Artificial antibodies to corticosteroids prepared by molecular imprinting

US 2003 049870 Magnus et al

Selective affinity material, preparation there of by molecular imprinting, and use of the same (selective affinity material, preparation of the material and its application by molecular imprinting)

US 2003 113234 Murray

Polymer based permeable membrane for removal of ions (for removing ions based on a permeable membrane polymer)

US 2003 059346 Murray

Method and apparatus for environmental phosphate/nitrate pollution removal using a selectively permeable molecularly imprinted polymermembrane

US 6,248,842 Singh et al

Synthetic polymer matrices including pro-organized chelation sites for the selective and reversible binding of metals (synthetic polymer matrix containing pre-organized chelation sites for selective and reversible metal binding)

WO 99 15,707 John et al

Detection and extraction of an ion in a solution, particularly uraniumion (ions in solution, especially the detection and extraction of uranium ions)

US 6,251,280 Dai et al

Imprint coating synthesis of selective functionalized ordered mesoporous sorbents for separation and sensors

non-patent literature

Garcia et al., Tetrahedron Lett., 39 (1998) 8651

Ionic imprinting effect in gadolinium/lanthanum separation (gadolinium/lanthanum separation ion imprinting effect)

Vigneau et al., Anal. Chim. Acta, 435 (2001) 75

Ionic imprinted resins based on EDTA and DTPA derivatives forlanthanides(III) separation

Vigneau et al., Chem. Lett. (2002) 202

Solid-Liquid separation of lanthanide/lanthanide andlanthanide/actinide using ionic imprinted polymer based on a DTPA derivative

Biju et al., Anal. Chim. Acta, 478 (2003) 43

Ion imprinted polymer particles: synthesis.Characterization and dysprosium ion uptake properties suitable for analytical applications

Biju et al., Talanta, 60 (2003) 747

Effect of γ-irradiation of ion imprinted polymer(IIP) particles for preconcentrative separation of dysprosium from other selected lanthanides )

Claims (9)

1. be used for the synthetic method of the ion imprinted polymer particle of solid phase extractions pre-concentration erbium ion, described method comprises:

(a) with 5,7-dichloro-8-hydroxyquinoline and 4-vinylpridine form the mixed ligand ternary complex of erbium trace ion;

(b) described ternary complex is dissolved in the suitable pore former, forms the preceding mixture of polymerization;

(c) mixture in the step (b) is combined with function monomer and cross-linking monomer, and carry out polymerisation, obtain polymeric material by γ-radiation or photochemical polymerization and thermal polymerization;

(d) polymeric material that obtains in the step (c) is ground, sieving, preparation erbium ion imprinted polymer particle;

(e) with the material that embeds the trace ion in the polymer particle of optionally lixiviate step of inorganic acid (d).

2. the method for claim 1, wherein said γ-radiation are that the function as methyl methacrylate (function monomer) concentration carries out.

3. the method for claim 1, wherein said photochemical polymerization are that the function as the UV radiated time carries out.

4. the method for claim 1, wherein said thermal polymerization are that the function as ethylene glycol dimethacrylate (cross-linking monomer) concentration carries out.

5. the method for claim 1, wherein said function monomer is selected from 4-vinylpridine and methyl methacrylate.

6. the method for claim 1, wherein said cross-linking monomer comprises ethylene glycol dimethacrylate.

7. the method for claim 1, wherein said reaction is with 2,2 '-azodiisobutyronitrile is realized as the initator of step (c).

8. the method for claim 1, wherein grinding with sieving in the step (d) carried out after erbium ion imprinted polymer material drying.

9. the method for claim 1 wherein is used for the inorganic acid of lixiviate and comprises HCl.

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