Aluminum-doped, iminodiacetic acid group-containing chelate resins

Abstract

The present invention relates to aluminum-doped chelate resins containing iminodiacetic acid groups, to a production process for aluminum-doped chelate resins containing iminodiacetic acid groups, and to a device comprising at least one layer of at least one aluminum-doped chelate resin containing iminodiacetic acid groups, and to the uses of this device and of the chelate resins for removal of fluoride from water.

Claims

1. An aluminum-doped chelate resin for absorption of anions, the resin comprising a polymer comprising a plurality of phenyl groups functionalized at a first substitution level of 0.6 to 1.5 with functional groups represented by the structural formula (I)
CH.sub.2NR.sub.2,(I) where each R is independently H or CH.sub.2COO.sup.?; the nitrogen is functionalized with acetate groups at a functionalization level of 1.4 to 1.65; and the acetate ions are conjugated with AIX, where X is any monovalent anion.

2. The resin according to claim 1, wherein the first substitution level is 0.6 to 1.2.

3. The resin according to claim 1, wherein the first substitution level is 0.7 to 0.9.

4. The resin according to claim 1, wherein: the polymer comprises repeat units derived from at least one monovinylaromatic compound and at least one polyvinylaromatic compound; and X is nitrate, nitrite, hydrogensulfate, hydrogencarbonate or a halide.

5. The resin according to claim 1, wherein: the monovinylaromatic compounds include styrene, vinyltoluene, ethylstyrene, ?-methylstyrene, chlorostyrene, chloromethylstyrene, alkyl acrylates or alkyl methacrylates; the polyvinylaromatic compounds include divinylbenzene, divinyltoluene, trivinylbenzene, divinylnaphthalene, trivinylnaphthalene, 1,7-octadiene, 1,5-hexadiene, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate or allyl methacrylate; and X is halide.

6. The resin according to claim 3, wherein the monovinylaromatic compound is styrene; the polyvinylaromatic compound divinylbenzene; and X is chlorine.

7. A process for producing the chelate resin as claimed in claim 1, the process comprising: converting monomer droplets composed of at least one monovinylaromatic compound, at least one polyvinylaromatic compound, at least one porogen, and at least one initiator to a crosslinked bead polymer; phthalimidomethylating aromatic groups of the crosslinked bead polymer at the first substitution level of 0.6 to 1.5 with phthalimide derivatives to produce phthalimidomethylated bead polymer; converting the phthalimidomethylated bead polymer to aminomethylated bead polymer to produce aminomethylated bead polymer; reacting the aminomethyl groups of the aminomethylated bead polymer with chloroacetic acid or salts thereof to produce chelate resins having iminoacetate groups at the functionalization level of 1.4 to 1.65; and contacting the chelate resin containing aminoacetate groups with an aluminum salt solution of a trivalent aluminum ion to produce the chelate resin.

8. The process according to claim 7, wherein: the phthalimidomethylation reaction comprises a molar ratio of phthalimide derivative to bead polymer of 0.7 mol to 1.7 mol; and the reaction with chloroacetic acid comprises a molar ratio of chloroacetic acid or salts thereof to aminomethylated bead polymer of 1.8:1 to 2.5:1 for functionalization of amino groups at the functionalization level of 1.4 to 1.65.

9. The process according to claim 8, wherein the phthalimidomethylation is conducted at a temperature of 60? C. to 80? C.

10. The process according to claim 9, wherein the phthalimidomethylation comprises a condensation of the phthalimide derivative with the bead polymer using a catalyst in a molar ratio of 0.1:1 to 0.45:1 in relation to the amount of bead polymer used.

11. The process as claimed in claim 10, wherein the contacting of the chelate resin containing iminoacetate groups with an aluminum salt solution comprises contacting the resin with 2 to 6 mol of aluminum based on one liter of chelate resin containing iminoacetate groups.

12. The process according to claim 7, wherein: the phthalimidomethylation reaction comprises a molar ratio of phthalimide derivative to bead polymer of 0.7 mol to 1.35 mol; and the reaction with chloroacetic acid comprises a molar ratio of chloroacetic acid or salts thereof to aminomethylated bead polymer of 1.8:1 to 2.5:1 for functionalization of the amino groups at the functionalization level of 1.4 to 1.65.

13. A device for removing fluoride from water, the device comprising at least one layer of at least one aluminum-doped chelate resin containing iminoacetate groups as claimed in claim 1.

14. A method for removing fluoride from water, the method comprising contacting water containing fluoride with the aluminum-doped chelate resin of claim 1 to absorb fluoride ions from the water.

Description

EXAMPLES

Example 1

a) Preparation of Monodisperse Macroporous Bead Polymer Based on Styrene, Divinylbenzene and Ethylstyrene

(1) A 10 L glass reactor is charged with 3000 g of deionized water, and a solution of 10 g of gelatin, 16 g of disodium hydrogenphosphate dodecahydrate and 0.73 g of resorcinol in 320 g of deionized water is added and mixed in. The mixture is equilibrated to 25? C. Subsequently, while stirring, a mixture of 3200 g of microencapsulated monomer droplets having a narrow particle size distribution, composed of 3.6% by weight of divinylbenzene and 0.9% by weight of ethylstyrene (used in the form of a commercial isomer mixture of divinylbenzene and ethylstyrene with 80% divinylbenzene), 0.5% by weight of dibenzoyl peroxide, 56.2% by weight of styrene and 38.8% by weight of isododecane (technical isomer mixture having a high proportion of pentamethylheptane) is given, the microcapsule consisting of a formaldehyde-hardened complex coacervate composed of gelatin and a copolymer of acrylamide and acrylic acid, and 3200 g of aqueous phase having a pH of 12 are added. The mean particle size of the monomer droplets is 460 ?m.

(2) The mixture is stirred and polymerized to completion by increasing the temperature in accordance with a temperature programme beginning at 25? C. and ending at 95? C. The mixture is cooled, washed through a 32 ?m sieve and then dried at 80? C. under reduced pressure. This gives 1893 g of a polymer in bead form having a mean particle size of 440 ?m, narrow particle size distribution and smooth surface.

(3) The polymer has a chalky white appearance and a bulk density of about 370 g/L.

b) Preparation of the Monodisperse Amidomethylated Bead Polymer

(4) 2122 mL of dichloroethane, 417.1 g of phthalimide and 245.7 g of 36% by weight formalin form an initial charge at room temperature. The pH of the suspension is adjusted to 5.5 to 6 using sodium hydroxide solution. The water is then removed by distillation. Then 30.6 g of sulfuric acid are metered in. The water formed is removed by distillation. The mixture is cooled. At 30? C., 111.7 g of 65% oleum and then 371.4 g of monodisperse bead polymer prepared in accordance with process step a) from example 1 are metered in. The suspension is heated to 70? C. and stirred at this temperature for a further 6.5 hours. The reaction liquid is drawn off, demineralized water is metered in and residual dichloroethane is removed by distillation.

(5) Yield of amidomethylated bead polymer: 1600 mL

(6) Nitrogen content: 4.5% by weight

(7) Dry weight: 0.473 gram per mL

c) Preparation of the Monodisperse Aminomethylated Bead Polymer

(8) Into 1580 mL of amidomethylated bead polymer are metered 866 mL of demineralized water and 608.4 g of 50% by weight sodium hydroxide solution at room temperature. The suspension is heated to 180? C. and stirred at this temperature for 8 hours.

(9) The resultant aminomethylated bead polymer is washed with demineralized water.

(10) Yield of monodisperse aminomethylated bead polymer: 1367 mL

(11) The total yield obtainedby extrapolationis 1384 mL.

(12) Composition by Elemental Analysis:

(13) Carbon: 82.7% by weight

(14) Hydrogen: 8.4% by weight

(15) Nitrogen: 8.0% by weight

(16) Oxygen: 2.0% by weight

(17) Amount of aminomethyl groups in mol per liter of aminomethylated bead polymer: 1.76 mol/L.

(18) It can be calculated from this that, on statistical average, per aromatic ring originating from the styrene and divinylbenzene units0.78 hydrogen atom has been replaced by aminomethyl groups.

d) Production of the Monodisperse Chelate Resin Having Chelating Groups of the Iminoacetic Acid Type

(19) Into 769 mL of demineralized water are metered, at room temperature, 730 mL of aminomethylated bead polymer from example 1c). The suspension is heated to 90? C. Into this suspension are metered, within 6 hours, 345 g of an aqueous solution having an 80% by weight content of monochloroacetic acid. At the same time, the pH of the suspension is kept at pH 9.2 by metered addition of 50% by weight sodium hydroxide solution. Subsequently, the mixture is heated to 95? C. and the suspension is adjusted to pH 10.5 with 50% by weight sodium hydroxide solution. The mixture is stirred at pH 10.5 and 95? C. for a further 6 hours.

(20) Thereafter, the suspension is cooled. The resin is washed with demineralized water until it is free of chloride.

(21) Yield: 1400 mL of monodisperse chelate resin

(22) original: 96% perfect beads of 100 beads examined

(23) After rolling test: 90% perfect beads of 100 beads examined

(24) By swelling stability: 96% perfect beads of 100 beads examined

(25) Total capacity of the resin: 2.1 mol/L of resin?amount of weakly acidic iminodiacetic acid groups in the chelate resin

(26) TC/N ratio: 1.60

(27) According to this, on statistical average, 1.60 of the two hydrogen atoms in the primary amino groups have been replaced by acetic acid groups.

(28) Dry weight: 343 grams per liter of resin

(29) Mean bead diameter: 610?

(30) Identity coefficient: 1.07

e) Doping of the Resins with Aluminum

(31) 110 mL of chelate resin from example d) are installed into a chromatography column having a frit base. A 1 liter beaker is initially charged with 550 mL of a 1 normal solution of AlCl.sub.3 in demineralized water. By means of a peristaltic pump, the aluminum chloride solution is then pumped through the resin bed in downward flow and back into the beaker again for one hour.

(32) The rate of pumped circulation is 10 BV/h, i.e. 1.1 liter/h. The resin becomes laden with aluminum and shrinks by 10% in volume to 100 mL.

(33) Thereafter, the aluminum chloride solution is discarded and 1 liter of deionized water is introduced into the beaker. The deionized water is conveyed through the resin into the eluate at a pumping rate of 1 liter per hour (10 BV/h). The deionized water rinses excess aluminum off the chelate resin resin. Thereafter, the material is ready for operation.

(34) Resin volume: 100 mL

(35) 100 mL of resin contain 3.2 grams of aluminum.

(36) Mean bead diameter: 590?

(37) Identity coefficient: 1.07

Example 2

Fluoride Adsorption Experiment on an Aluminum-Doped Resin Having a Functionalization Level=1.5

(38) Resin specimen A (aluminum-doped chelate resin containing iminodiacetic acid groups, prepared analogously to example 1): First substitution level: 0.78, functionalization level 1.5, Mean grain diameter=0.65

(39) 100 mL of the aluminum-doped resin in the abovementioned chromatography column, for downward flow operation, are connected at the feed via a pump to a 200 liter reservoir vessel and at the drain to a 200 liter collecting vessel.

(40) The 200 liter vessel is initially charged with 200 liters of demineralized water and 28 g of CaCl.sub.2, 53 g of Na.sub.2SO.sub.4*6H.sub.2O, 100 g of NaCl and 4.4 g of NaF are dissolved therein. The resulting ionic composition of the solution is shown in table 1.

(41) TABLE-US-00001 TABLE 1 Composition of the feed solution Concentration Concentration Ion [ppm] [meq/L] Calcium 51 2.54 Sodium 257 11.17 Chloride 393 11.09 Sulfate 102 2.13 Fluoride 10 0.53 Total 813 27.46

(42) At regular time intervals, the fluoride concentrations are measured in the eluate. The volume of filtrate in which en eluate concentration of <1.5 mg/L is measured is used to calculate, via mass balancing, the usable capacity (UC) reported as the mass of fluoride separated out (in g) per liter of chelate exchanger (in the aluminum form initially charged).

(43) The results are shown in table 2:

(44) TABLE-US-00002 TABLE 2 Usable capacities (UC) of resin A: Resin specimen UC (g of F per L of resin) Resin specimen A (aluminum-doped 2.8 chelate resin containing iminodiacetic acid groups, prepared analogously to example 1): First substitution level: 0.78 Functionalization level: 1.5 Mean grain diameter: 0.65

Comparative Example

Fluoride Adsorption Experiment on an Aluminum-Doped Resin Having a Functionalization Level=2.0

(45) Resin specimen B (aluminum-doped chelate resin containing iminodiacetic acid groups): First substitution level: 0.78, functionalization level=2.0, Mean grain diameter=0.65

(46) 100 mL of the aluminum-doped resin in the abovementioned chromatography column, for downward flow operation, are connected at the feed via a pump to a 200 liter reservoir vessel and at the drain to a 200 liter collecting vessel.

(47) The 200 liter vessel is initially charged with 200 liters of demineralized water and 28 g of CaCl.sub.2, 53 g of Na.sub.2SO.sub.4*6H.sub.2O, 100 g of NaCl and 4.4 g of NaF are dissolved therein. The resulting ionic composition of the solution is shown in table 2,

(48) TABLE-US-00003 TABLE 2 Composition of the feed solution Concentration Concentration Ion [ppm] [meq/L] Calcium 51 2.54 Sodium 257 11.17 Chloride 393 11.09 Sulfate 102 2.13 Fluoride 10 0.53 Total 813 27.46

(49) At regular time intervals, the fluoride concentrations are measured in the eluate. The volume of filtrate in which an eluate concentration of <1.5 mg/L is measured is used to calculate, via mass balancing, the usable capacity (UC) reported as the mass of fluoride separated out (in g) per liter of chelate exchanger (in the aluminum form initially charged).

(50) The results are shown in table 3:

(51) TABLE-US-00004 TABLE 3 Usable capacities (UC) of the resin: Resin specimen UC (g of F per L of resin) Resin specimen B: (aluminum-doped 0.7 chelate resin containing iminodiacetic acid groups): First substitution level: 0.78 Functionalization level: 2.0 Mean grain diameter: 0.65

(52) It is apparent from the data that resin specimen A having a second substitution level of 1.5 exhibits a fluoride absorption 3 to 4 times higher than, by comparison, resin specimen B having a substitution level of 2.

(53) Analytical Methods

(54) Determination of Amount of Basic Aminomethyl Groups in Aminomethylated Crosslinked Polystyrene Bead Polymer

(55) 100 mL, of the aminomethylated bead polymer are agitated down in the tamp volumeter and subsequently washed with demineralized water into a glass column. 1000 mL, of 2% by weight aqueous sodium hydroxide solution are passed through the column in the course of 1 hour and 40 minutes. De mineralized water is then passed through until 100 mL of eluate with added phenolphthalein have a consumption of 0.1 N (0.1 normal) hydrochloric acid of not more than 0.05 mL.

(56) 50 mL of this resin are admixed in a beaker with 50 L of demineralized water and 100 mL of IN hydrochloric acid. The suspension is stirred for 30 minutes and then filled into a glass column. The liquid is drained off. A further 100 mL of 1 N hydrochloric acid are passed through the resin for 20 minutes. 200 mL of methanol are then passed through. All the eluates are collected and combined and titrated with 1 N aqueous sodium hydroxide solution against methyl orange.

(57) The number of aminomethyl groups in 1 liter of aminomethylated resin computes according to the following formula: (200?V).Math.20=mol of aminomethyl groups per liter of resin.

(58) Determination of the Amount of Weakly Acidic Iminodiacetic Acid Groups in the Chelate Resin and Determination of the Substitution Level of the Hydrogen Atoms in the Primary Amino Groups by Acetic Acid GroupsTC/N Ratio

(59) 100 mL of exchanger are introduced into a filter column and elided with 500 mL of 3% by weight hydrochloric add within 1.5 hours. The column is then washed with demineralized water until the eluate is neutral.

(60) 50 mL of resin are taken from the amount of resin remaining and introduced into a column. 0.1 N sodium hydroxide solution is filtered through the resin. The eluate is collected in a 250 volumetric flask in each case. This liquid is titrated with 1 N hydrochloric acid against methyl orange. 0.1 N sodium hydroxide solution is filtered through the resin until 258 mL of eluate has a consumption of 24.5 to 25 mL of 1 N hydrochloric acid. Once the test has ended, the volume of exchanger in Na form is determined.
Total capacity (TC)=(X*25?sum of V)?3 in mol/L of exchanger

(61) X=number of eluate fractions

(62) Sum of V=total consumption in mL of 1 N hydrochloric acid in the titration