Magnetic strong base anion exchange resin with high mechanical strength, and preparation method thereof

Abstract

A magnetic strong base anion exchange resin with high mechanical strength and a preparation method thereof, belonging to the field of resin materials. The preparation method comprises steps of: adding a conventional strong base anion exchange resin to a mixture of trivalent iron salt and divalent iron salt, and then mixing the resin adsorbed with the iron salt with aqueous ammonia so that Fe.sub.3O.sub.4 nanoparticles are contained in the resin structure. Then, the resin containing Fe.sub.3O.sub.4 nanoparticles is added to alcoholic solution dissolved with silane coupling agent to form a dense SiO.sub.2 coating on the surface of the resin, so as to obtain magnetic strong base anion exchange resin with high mechanical strength.

Claims

1. A method for preparing a magnetic strong base anion exchange resin, wherein the magnetic strong base anion exchange resin is strong base anion exchange resin particles, the resin particles contain iron-containing magnetic particles, and the surface of the resin particles are coated with silica, the method comprising the following steps of: (1) preparing iron salt solution containing trivalent iron salt and divalent iron salt, adding a strong base anion exchange resin to the iron salt solution, and mixing uniformly; a ratio of total mass of valent iron salt and the divalent iron salt is 1:7.5 to 1:48; the mass ratio of the trivalent iron salt to the divalent iron salt in the iron salt solution is 1:1 to 5:1; (2) separating the strong base anion exchange resin from the mixture obtained in the step (1), drying, and reacting with aqueous ammonia at 35° C. to 95° C.; (3) adding silane coupling agent and alcohol to the reaction solution obtained in the step (2), or adding alcoholic solution of silane coupling agent to the reaction solution obtained in the step (2), and reacting at 25° C. to 75° C.; and (4) separating the strong base anion exchange resin from the reaction solution obtained in the step (3), and then adding silane coupling agent, alcohol and aqueous ammonia; or, separating the strong base anion exchange resin from the reaction solution obtained in the step (3), and then adding alcoholic solution of silane coupling agent and the aqueous ammonia; and, reacting at 25° C. to 75° C.; drying to obtain the magnetic strong base anion exchange resin; wherein the magnetic strong base anion exchange resin has a strong base anion exchange capacity of 2.0 to 4.3 mmol/g, a moisture holding capacity of 40% to 70%, a Fe content of 20% to 40%, an Si content of 0.001% to 2.212%, a Fe dissolution rate of 0.5% to 2.1%, a sphericity after attrition of 80% to 99%, a true density in wet state of 1.1 to 1.5 g/mL, a bulk density in wet state of 0.7 to 1.0 g/mL, and a deposition rate of 65 to 100 m/h in pure water at 25° C.; in the step (2) or (4), the mass ratio of the resin to ammonia in the aqueous ammonia is 1:0.2 to 1:3.5; the mass fraction of the ammonia in the aqueous ammonia water is 10 to 32%; in the step (3) or (4), the silane coupling agent is tetraethyl silicate or vinyltrimethoxysilane; the alcohol is methanol or ethanol; the ratio of the strong base anion exchange resin and the silane coupling agent is 1:0.2 to 1:5 g/mL by mass-to-volume; the ratio of the silane coupling agent to the alcohol is 1:5 to 1:50 by volume.

2. The method for preparing the magnetic strong base anion exchange resin according to claim 1, wherein, in the step (1), the trivalent iron salt is one or more selected from the group consisting of ferric chloride hydrate, ferric sulfate hydrate and ferric nitrate hydrate; the divalent iron salt is one or more selected from the group consisting of ferrous chloride hydrate, ferrous sulfate hydrate and ferrous nitrate hydrate; the mass fraction of the iron salt solution is 5% to 50%, optionally 5% to 40%; and the ratio of the mass of the strong base anion exchange resin to the total mass of the trivalent iron salt and the divalent iron salt is 1:3 to 1:60, optionally 1:7.5 to 1:48.

3. The method for preparing the magnetic strong base anion exchange resin according to claim 1, wherein in the step (2), the reaction time is 0.5 h to 3 h.

4. The method for preparing the magnetic strong base anion exchange resin according to claim 1, wherein the strong base anion exchange resin particles are acrylic strong base anion exchange resin particles, and the iron-containing magnetic particles are Fe.sub.3O.sub.4 nanoparticles or Fe.sub.2O.sub.3 nanoparticles.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is an electron micrograph of an anion exchange resin D213 made in China in Embodiment 1;

(2) FIG. 2 is an electron micrograph of a magnetic strong base anion exchange resin finally synthesized in Embodiment 1; and

(3) FIG. 3 shows a hysteresis loop of the magnetic strong base anion exchange resin finally synthesized in Embodiment 1, where the test tubes {circle around (1)} and {circle around (2)} at the upper left contain the anion exchange resin D213 made in China in Embodiment 1 and the magnetic strong base anion exchange resin finally synthesized in Embodiment 1, respectively.

DETAILED DESCRIPTION OF THE INVENTION

(4) The magnetic strong base anion exchange resin with high mechanical strength and preparation method thereof provided by the present invention will be further described by the following embodiments.

Embodiment 1

(5) 80 g of ferric chloride hydrate and 80 g of ferrous chloride hydrate were dissolved in water to obtain iron salt solution having a mass fraction of 5%, and then added with 10 g of an anion exchange resin D213 (the anion exchange resin D213 made in China, by Jiangsu Jinkai Resin Chemical Co., Ltd.). The temperature of the reactor was adjusted to 75° C., 100 ml of aqueous ammonia having a mass concentration of 32% was added in the reactor, and the reaction system was reacted for 1 h. Then, the temperature of the reactor was adjusted to 50° C., 10 ml of tetraethyl silicate and 100 ml of methanol were added in the reactor, and the reaction system was reacted for 1 h. Subsequently, the resin was separated from the mixture and then added with 10 ml of aqueous ammonia having a mass concentration of 32%, 10 ml of tetraethyl silicate and 100 ml of methanol, and the reaction system was reacted for 1 h at 50° C. At the end of reaction, the resin was dried. The performances of the synthesized magnetic resin were shown in Table 1.

Embodiment 2

(6) 80 g of ferric chloride hydrate and 40 g of ferrous chloride hydrate were dissolved in water to obtain iron salt solution having a mass fraction of 15%, and then added with 8 g of an anion exchange resin D205 (the anion exchange resin D205 made in China, by Jiangsu Jinkai Resin Chemical Co., Ltd.). The temperature of the reactor was adjusted to 90° C., 70 ml of aqueous ammonia having a mass concentration of 10% was added in the reactor, and the reaction system was reacted for 0.5 h. Then, the temperature of the reactor was adjusted to 70° C., 10 ml of vinyltrimethoxysilane and 50 ml of methanol were added in the reactor, and the reaction system was reacted for 2 h. Subsequently, the resin was separated from the mixture and then added with 20 ml of aqueous ammonia having a mass concentration of 10%, 10 ml of vinyltrimethoxysilane and 50 ml of methanol, and the reaction system was reacted for 2 h at 70° C. At the end of reaction, the resin was dried. The performances of the synthesized magnetic resin were shown in Table 1.

Embodiment 3

(7) 80 g of ferric chloride hydrate and 25 g of ferrous sulfate hydrate were dissolved in water to obtain iron salt solution having a mass fraction of 25%, and then added with 5 g of an anion exchange resin (Purolite®A520E). The temperature of the reactor was adjusted to 70° C., 40 ml of aqueous ammonia having a mass concentration of 25% was added in the reactor, and the reaction system was reacted for 2 h. Then, the temperature of the reactor was adjusted to 40° C., 5 ml of vinyltrimethoxysilane and 100 ml of ethanol were added in the reactor, and the reaction system was reacted for 4 h. Subsequently, the resin was separated from the mixture and then added with 10 ml of aqueous ammonia having a mass concentration of 25%, 5 ml of vinyltrimethoxysilane and 100 ml of ethanol, and the reaction system was reacted for 5 h at 40° C. At the end of reaction, the resin was dried. The performances of the synthesized magnetic resin were shown in Table 1.

Embodiment 4

(8) 80 g of ferric sulfate hydrate and 20 g of ferrous sulfate hydrate were dissolved in water to obtain iron salt solution having a mass fraction of 40%, and then added with 4 g of a magnetic acrylic strong base anion exchange microsphere resin (the resin disclosed in Chinese Patent CN101781437A). The temperature of the reactor was adjusted to 55° C., 30 ml of aqueous ammonia having a mass concentration of 10% was added in the reactor, and the reaction system was reacted for 3 h. Then, the temperature of the reactor was adjusted to 30° C., 5 ml of tetraethyl silicate and 150 ml of ethanol were added in the reactor, and the reaction system was reacted for 3 h. Subsequently, the resin was separated from the mixture and then added with 10 ml of aqueous ammonia having a mass concentration of 10%, 5 ml of tetraethyl silicate and 150 ml of ethanol, and the reaction system was reacted for 2 h at 30° C. At the end of reaction, the resin was dried. The performances of the synthesized magnetic resin were shown in Table 1.

Embodiment 5

(9) 80 g of ferric chloride hydrate and 16 g of ferrous chloride hydrate were dissolved in water to obtain iron salt solution having a mass fraction of 25%, and then added with 2 g of an anion exchange resin D213 (the anion exchange resin D213 made in China, by Jiangsu Jinkai Resin Chemical Co., Ltd.). The temperature of the reactor was adjusted to 40° C., 10 ml of aqueous ammonia having a mass concentration of 32% was added in the reactor, and the reaction system was reacted for 0.5 h. Then, the temperature of the reactor was adjusted to 55° C., 2 ml of vinyltrimethoxysilane and 80 ml of methanol were added in the reactor, and the reaction system was reacted for 6 h. Subsequently, the resin was separated from the mixture and then added with 5 ml of aqueous ammonia having a mass concentration of 32%, 2 ml of vinyltrimethoxysilane and 80 ml of methanol, and the reaction system was reacted for 3 h at 55° C. At the end of reaction, the resin was dried. The performances of the synthesized magnetic resin were shown in Table 1.

Embodiment 6

(10) 40 g of ferric sulfate hydrate and 40 g of ferrous sulfate hydrate were dissolved in water to obtain iron salt solution having a mass fraction of 15%, and then added with 10 g of an anion exchange resin D205 (the anion exchange resin D205 made in China, by Jiangsu Jinkai Resin Chemical Co., Ltd.). The temperature of the reactor was adjusted to 55° C., 10 ml of aqueous ammonia having a mass concentration of 30% was added in the reactor, and the reaction system was reacted for 1 h. Then, the temperature of the reactor was adjusted to 45° C., 2 ml of tetraethyl silicate and 100 ml of methanol were added in the reactor, and the reaction system was reacted for 2 h. Subsequently, the resin was separated from the mixture and then added with 100 ml of aqueous ammonia having a mass concentration of 30%, 2 ml of tetraethyl silicate and 100 ml of methanol, and the reaction system was reacted for 0.5 h at 45° C. At the end of reaction, the resin was dried. The performances of the synthesized magnetic resin were shown in Table 1.

Embodiment 7

(11) 40 g of ferric chloride hydrate and 20 g of ferrous chloride hydrate were dissolved in water to obtain iron salt solution having a mass fraction of 10%, and then added with 8 g of a magnetic styrene strong base anion exchange microsphere resin (the resin disclosed in Chinese Patent CN101708475B). The temperature of the reactor was adjusted to 65° C., 20 ml of aqueous ammonia having a mass concentration of 25% was added in the reactor, and the reaction system was reacted for 2 h. Then, the temperature of the reactor was adjusted to 30° C., 5 ml of tetraethyl silicate and 150 ml of methanol were added in the reactor, and the reaction system was reacted for 3 h. Subsequently, the resin was separated from the mixture and then added with 70 ml of aqueous ammonia having a mass concentration of 25%, 5 ml of tetraethyl silicate and 150 ml of methanol, and the reaction system was reacted for 6 h at 30° C. At the end of reaction, the resin was separated and dried. The performances of the synthesized magnetic resin were shown in Table 1.

Embodiment 8

(12) 40 g of ferric chloride hydrate and 15 g of ferrous chloride hydrate were dissolved in water to obtain iron salt solution having a mass fraction of 5%, and then added with 5 g of an anion exchange resin D213 (the anion exchange resin D213 made in China, by Jiangsu Jinkai Resin Chemical Co., Ltd.). The temperature of the reactor was adjusted to 75° C., 30 ml of aqueous ammonia having a mass concentration of 20% was added in the reactor, and the reaction system was reacted for 3 h. Then, the temperature of the reactor was adjusted to 55° C., 5 ml of vinyltrimethoxysilane and 100 ml of methanol were added in the reactor, and the reaction system was reacted for 0.5 h. Subsequently, the resin was separated from the mixture and then added with 30 ml of aqueous ammonia having a mass concentration of 20%, 5 ml of vinyltrimethoxysilane and 100 ml of methanol, and the reaction system was reacted for 3 h at 55° C. At the end of reaction, the resin was dried. The performances of the synthesized magnetic resin were shown in Table 1.

Embodiment 9

(13) 40 g of ferric sulfate hydrate and 10 g of ferrous chloride hydrate were dissolved in water to obtain iron salt solution having a mass fraction of 25%, and then added with 4 g of an anion exchange resin (Purolite®A520E). The temperature of the reactor was adjusted to 65° C., 40 ml of aqueous ammonia having a mass concentration of 5% was added in the reactor, and the reaction system was reacted for 2 h. Then, the temperature of the reactor was adjusted to 40° C., 10 ml of tetraethyl silicate and 100 ml of methanol were added in the reactor, and the reaction system was reacted for 4 h. Subsequently, the resin was separated from the mixture and then added with 20 ml of aqueous ammonia having a mass concentration of 5%, 10 ml of tetraethyl silicate and 100 ml of methanol, and the reaction system was reacted for 2 h at 40° C. At the end of reaction, the resin was dried. The performances of the synthesized magnetic resin were shown in Table 1.

Embodiment 10

(14) 40 g of ferric sulfate hydrate and 8 g of ferrous sulfate hydrate were dissolved in water to obtain iron salt solution having a mass fraction of 40%, and then added with 2 g of a magnetic acrylic strong base anion exchange microsphere resin (the resin disclosed in Chinese Patent CN101781437A). The temperature of the reactor was adjusted to 90° C., 10 ml of aqueous ammonia having a mass concentration of 10% was added in the reactor, and the reaction system was reacted for 1 h. Then, the temperature of the reactor was adjusted to 70° C., 10 ml of tetraethyl silicate and 50 ml of ethanol were added in the reactor, and the reaction system was reacted for 6 h. Subsequently, the resin was separated from the mixture and then added with 10 ml of aqueous ammonia having a mass concentration of 10%, 10 ml of tetraethyl silicate and 50 ml of ethanol, and the reaction system was reacted for 1 h at 70° C. At the end of reaction, the resin was dried. The performances of the synthesized magnetic resin were shown in Table 1.

(15) Embodiment 11: The performances of the resin were measured by the following methods in the above embodiments, and the specific data was shown in Table 1.

(16) Fe content: for the measurement of the Fe content, please refer to HJ 781-2016: Solid waste. Determination of 22 metal elements. Inductively coupled plasma optical emission spectrometry.

(17) Si content: for the measurement of the Si content, please refer to GB/T 14506.28-2010: Methods for chemical analysis of silicate rocks.

(18) True density in wet state: for the measurement of the true density in wet state, please refer to GB 8330-87: Methods for the determination of true density of ion exchange resins in wet state.

(19) Bulk density in wet state: for the measurement of the bulk density in wet state, please refer to GB 8331-87: Methods for the determination of bulk density of ion exchange resins in wet state.

(20) Fe dissolution rate: for the Fe dissolution rate, please refer to the dissolution of Fe in the magnetic resin after the magnetic resin is immersed in 1 mol/L hydrochloric acid solution.

(21) Sphericity after attrition: for the measurement of the sphericity after attrition, please refer to GB/T 12598-2001: Determination for sphericity of ion exchange resins after attrition or osmotic-attrition.

(22) Moisture holding capacity: for the measurement of the moisture holding capacity, please refer to GB/T 5757-2008: Determination of moisture holding capacity of ion exchange resins.

(23) Deposition rate: for the measurement of the deposition rate, please refer to Chen Xiuzhi, et al., Hydraulic Property Tests of D113 Weak Acid Exchange Resins[J]. Journal of University of Science and Technology Beijing, 2001,23(5):398-400.

(24) Exchange capacity: for the measurement of the exchange capacity, please refer to GB/T 11992-1989: Strong basic anion exchange resins in chloride form-Determination of exchange capacity.

(25) TABLE-US-00001 TABLE 1 Performaes of resin True Bulk Fe Sphericity Moisture Fe Si density density dissolution after holding Deposition Exchange Magnet content content in wet state in wet state rate attrition capacity rate capacity resin (%) (%) (g/mL) (g/mL) (%) (%) (%) (m/h) (mmol/g) Embodiment 1 36 2.211 1.5 0.73 0.5 98 ± 1 62.4 91.77 3.98 Embodiment 2 31 1.837 1.3 0.76 1.0 89 ± 3 45.9 74.43 3.73 Embodiment 3 26 1.348 1.1 0.76 1.6 82 ± 5 47.9 87.34 2.97 Embodiment 4 30 1.798 1.3 0.73 0.6 93 ± 2 51.7 82.59 4.04 Embodiment 5 34 1.956 1.4 0.68 0.5 96 ± 2 63.9 86.33 3.54 Embodiment 6 28 1.468 1.2 0.7 1.0 90 ± 2 46.1 76.49 3.62 Embodiment 7 29 1.521 1.2 0.69 0.7 92 ± 3 46.4 85.66 3.93 Embodiment 8 33 2.103 1.5 0.69 0.6 96 ± 1 65.0 85.49 3.82 Embodiment 9 25 1.217 1.1 0.77 1.2 80 ± 3 48.2 87.49 3.02 Embodiment 10 31 2.109 1.3 0.75 0.5 95 ± 2 50.8 84.32 4.15