Calcium polystyrene sulfonate and preparation method thereof

Abstract

The invention relates to the technical field of medicinal chemistry, and particularly discloses calcium polystyrene sulfonate and a preparation method thereof. The preparation method of the calcium polystyrenesulfonate comprises the following steps: S1, uniformly mixing sodium polystyrenesulfonate microspheres with an aqueous dispersion of zeolite, heating, mixing, carrying out solid-liquid separation, and washing to obtain primary sodium polystyrenesulfonate microspheres; s2, preparing the primary sodium polystyrenesulfonate microspheres into a suspension I, simultaneously introducing the suspension I and a calcium chloride solution into a micro-channel reactor, reacting, performing solid-liquid separation and washing to prepare a suspension II, simultaneously introducing the suspension II and a calcium chloride solution into the micro-channel reactor, reacting, performing solid-liquid separation and washing to prepare a suspension III, and preparing the primary sodium polystyrenesulfonate microspheres into the micro-channel reactor; and simultaneously introducing the suspension III and a calcium chloride solution into a micro-channel reactor, reacting, carrying out solid-liquid separation, washing, and drying to obtain the calcium polystyrene sulfonate. The calcium polystyrenesulfonate prepared by the invention has high calcium loading rate and potassium ion exchange capacity.

Description

Technical Field

[0001] This application relates to the technical field of pharmaceutical chemistry. More specifically, it relates to a calcium polystyrene sulfonate and a preparation method thereof. Background Art

[0002] Sodium polystyrene sulfonate, commonly known as potassium-lowering resin, is the first-generation drug for the treatment of chronic hyperkalemia. However, after it exchanges potassium ions in the blood, sodium ions are released, and the increased sodium load will exacerbate the volume load of patients with hypertension, heart failure or end-stage renal disease. While calcium polystyrene sulfonate releases calcium rather than sodium after exchanging with potassium in the blood, and it has the advantages of not increasing the sodium content in the body and having calcium supplementation. Therefore, calcium polystyrene sulfonate is expected to become a better alternative for the treatment of chronic hyperkalemia, bringing better treatment effects and quality of life to patients.

[0003] The patent application document with the publication number CN101091926A discloses a preparation method of a calcium polystyrene sulfonate cation exchange resin, which converts and purifies an industrial-grade sodium polystyrene sulfonate resin that has been treated by one or several processes such as removing free polystyrene, residual 1,2-dichloroethane and bleaching described in the patent application into a calcium polystyrene sulfonate resin with a calcium ion-containing composition. The calcium ion-containing composition consists of calcium ions and their counter ions, complexing agents, pH regulators and water. The counter ion is chloride ion, and the complexing agent is a composition of one, two or more of the following agents: ethylenediaminetetraacetic acid, ethylenediaminetriaminepentaacetic acid, nitrilotriacetic acid, citric acid and their calcium salts or sodium salts; the volume ratio of the calcium ion-containing composition to the resin is 2-9.

[0004] In this technology, when preparing the calcium polystyrene sulfonate cation exchange resin, the complexing agents used are a composition of one or two or more of the following agents: ethylenediaminetetraacetic acid, ethylenediaminetriaminepentaacetic acid, nitrilotriacetic acid, citric acid and their calcium salts or sodium salts. These weak acids, weak bases and their calcium salts or sodium salts, as complexing agents, although they can form complexes with metal ions, their complexing ability with calcium ions is relatively weak. During the preparation process of the calcium polystyrene sulfonate cation exchange resin, they cannot effectively complex calcium ions and guide them into the resin structure, thus limiting the calcium loading rate in calcium polystyrene sulfonate. Summary of the Invention

[0005] In order to improve the calcium loading rate in calcium polystyrene sulfonate, this application provides a calcium polystyrene sulfonate and a preparation method thereof.

[0006] In the first aspect, this application provides a preparation method of calcium polystyrene sulfonate, adopting the following technical solution: A preparation method of calcium polystyrene sulfonate includes the following steps: S1: Mix the aqueous dispersion of sodium polystyrene sulfonate microspheres and zeolite evenly at a mass ratio of 1:(3 - 5), heat up to 40 - 60 °C, after mixing for 3 - 5 h, carry out solid-liquid separation, and after washing, obtain primary sodium polystyrene sulfonate microspheres; S2: Make the primary sodium polystyrene sulfonate microspheres into suspension one, and simultaneously introduce suspension one and calcium chloride solution with a mass fraction of 8% - 12% into a microchannel reactor. After reacting for 20 - 30 min, carry out solid-liquid separation, and after washing, make suspension two. Then introduce suspension two and calcium chloride solution with a mass fraction of 12% - 15% into the microchannel reactor simultaneously. After reacting for 20 - 30 min, carry out solid-liquid separation, and after washing, make suspension three. Then introduce suspension three and calcium chloride solution with a mass fraction of 15% - 20% into the microchannel reactor simultaneously. After reacting for 8 - 15 min, carry out solid-liquid separation, wash, dry, and pulverize to obtain calcium polystyrene sulfonate; The mass fraction of zeolite in the aqueous dispersion is 6% - 15%.

[0007] Preferably, the zeolite is 4A zeolite.

[0008] The beneficial effects are as follows: By using the aqueous dispersion of zeolite to pretreat the sodium polystyrene sulfonate microspheres, ion exchange occurs between the zeolite and the sodium polystyrene sulfonate microspheres, causing partial sodium ions on the microsphere surface to be exchanged, forming a local low-sodium environment on the microsphere surface, and opening up more active sites for subsequent calcium ion adsorption. At the same time, after ion exchange, the chemical environment and charge distribution on the microsphere surface change, making the activity of the sulfonic acid groups on the surface enhanced, which is more conducive to ion exchange with the calcium ions added subsequently.

[0009] After that, start the calcium conversion with a low-concentration calcium chloride solution first, which can make the calcium ions slowly exchange with the sodium ions on the surface of the primary sodium polystyrene sulfonate microspheres. This helps to avoid the overly violent exchange reaction due to too high calcium ion concentration and also avoid the amorphous precipitation caused by local supersaturation, thus making the exchange process more uniform, improving the calcium content of the calcium polystyrene sulfonate microspheres, and the stability of the product's own performance. As the concentration of the calcium chloride solution gradually increases, it can further promote the ion exchange reaction to proceed in a more complete direction, making more sodium ions be replaced by calcium ions, and further increasing the calcium ion loading rate and yield of the product.

[0010] Preferably, the preparation method of the aqueous dispersion of zeolite includes the following steps: Disperse polyethylene glycol in water, then add zeolite and mix evenly to obtain it.

[0011] Preferably, the dosage of polyethylene glycol is 4% - 6% of the mass of zeolite.

[0012] Preferably, the zeolite is 4A zeolite.

[0013] Preferably, the mass ratio of the sodium polystyrene sulfonate microspheres, the calcium chloride solution with a mass fraction of 8% - 12%, the calcium chloride solution with a mass fraction of 12% - 15%, and the calcium chloride solution with a mass fraction of 15% - 20% is 1:(5 - 7):(3 - 5):(2 - 4).

[0014] Preferably, in step S1, the washing is first carried out with water 3 - 5 times, and then with a calcium chloride solution with a mass fraction of 6% - 8% 2 - 4 times.

[0015] The beneficial effects are as follows: Washing with water 3 - 5 times first can remove some water-soluble impurities on the surface of the sodium polystyrene sulfonate microspheres, making the surface of the microspheres cleaner. After that, washing with a calcium chloride solution with a mass fraction of 6% - 8% 2 - 4 times can form a partial calcified layer on the surface of the microspheres, which can not only neutralize the excessive negative charges but also avoid complete saturation. During subsequent calcification, it can quickly penetrate the surface layer, drive the replacement of internal sodium ions, and improve the overall calcium ion loading rate.

[0016] Preferably, before use, the sodium polystyrene sulfonate microspheres are subjected to the following pretreatment steps: The sodium polystyrene sulfonate microspheres are successively washed with water, oxidized, pickled, washed with alcohol, and washed with alkali, then washed until neutral and dried to obtain the product.

[0017] Preferably, the oxidation adopts gradient oxidation. First, wash with a sodium hypochlorite solution with a mass fraction of 0.3% - 0.5% for 10 - 20 min, then immerse in a sodium hypochlorite solution with a mass fraction of 0.2% - 0.4% for 20 - 40 min, then carry out solid-liquid separation and washing.

[0018] Preferably, the pickling adopts two-stage pickling. First, wash with a hydrochloric acid solution with a mass fraction of 4% - 6% for 15 - 30 min, then immerse in a hydrochloric acid solution with a mass fraction of 3% - 5% for 3 - 5 h, then carry out solid-liquid separation and washing.

[0019] Preferably, the washing with alcohol is carried out by washing with ethanol and then immersing in ethanol for 6 - 8 h, then carrying out solid-liquid separation and washing.

[0020] Preferably, the washing with alkali is carried out by washing with sodium hydroxide with a mass fraction of 4% - 6% and then immersing in a sodium hydroxide solution with a mass fraction of 3% - 5% for 90 - 150 min.

[0021] The beneficial effects are as follows: By combining gradient oxidation and two-stage pickling, this method constructs a two-stage impurity removal system of "rapid oxidation - fine purification", which can not only more effectively remove impurities in the microspheres, maintain the original performance and structure of the microspheres, but also improve the pore structure of the sodium polystyrene sulfonate microspheres, thereby increasing the subsequent calcium ion loading rate.

[0022] First, through treatment with sodium hypochlorite solutions of different concentrations, gradient oxidation can gradually oxidize the impurities on the surface of the microspheres and decompose some organic impurities into smaller molecules such as carbon dioxide and water, avoiding damage to the microsphere structure. While removing impurities, it also releases or exposes the pores originally blocked or occupied by impurities in the microspheres, thus facilitating the improvement of the pore structure. The improvement of the pore structure can provide more channels and binding sites for subsequent calcium ions to enter, thereby increasing the calcium ion loading rate.

[0023] Second, two-stage pickling through treatment with hydrochloric acid solutions of different concentrations can more comprehensively remove residual impurities, including some impurities generated after oxidation or other substances that are difficult to remove. The further removal of impurities can make the pores of the microspheres more unobstructed, increase the effective utilization area of the pores, create better conditions for the loading of calcium ions, and contribute to the improvement of the calcium ion loading rate.

[0024] Finally, ethanol is used to displace water and form a protective film, inhibiting the swelling or shrinkage of the microspheres, maintaining the integrity of the porous structure, and avoiding damage to the pore structure during the treatment process, which affects the calcium ion loading. Then, residual acidic groups are neutralized with sodium hydroxide to reduce electrostatic agglomeration and improve the dispersion stability of the microspheres in the solution. Good dispersion enables the microspheres to come into contact with calcium ions more fully, which is beneficial to improving the calcium ion loading efficiency and loading amount.

[0025] Preferably, before use, the zeolite undergoes the following pretreatment steps: The zeolite is dispersed in a ferric chloride solution, heated to 50 - 70 °C, impregnated and mixed for 5 - 7 h, then solid-liquid separated, washed, and dried to obtain the product.

[0026] The concentration of the ferric chloride solution is 0.1 - 0.3 mol / L.

[0027] Preferably, the mass-volume ratio of the zeolite to the ferric chloride solution is 1 g : (5 - 10) ml.

[0028] The beneficial effects are as follows: Ferric ions are loaded into the layered structure of the zeolite through ion exchange, replacing some sodium ion sites, increasing the ion exchange ability for sodium ions in the sodium polystyrene sulfonate microspheres, and being able to more effectively reduce the sodium content in the sodium polystyrene sulfonate, creating favorable conditions for subsequent reactions with calcium chloride. From the perspective of ion exchange equilibrium, there is an exchange driving force for sodium ions in the environment around the microspheres, which promotes more sodium ions to be displaced from the sodium polystyrene sulfonate microspheres, reducing the shielding effect of sodium ions on the sulfonic acid groups. This exposes more active sites of the sulfonic acid groups, making them more likely to bind with calcium ions in subsequent reactions, ultimately increasing the calcium ion loading amount.

[0029] Preferably, before the calcium chloride solution is used, tartaric acid is added for mixing, and the mass fraction of tartaric acid in the calcium chloride solution is 0.1% - 0.3%.

[0030] By adopting the above technical solution, tartaric acid molecules can contact and complex with a small amount of free ferric ions that may exist in the solution, preventing them from reacting with calcium polystyrene sulfonate unnecessarily and avoiding the mixing of iron ion impurities into the product, which may affect the purity and performance of calcium polystyrene sulfonate. At the same time, when the tartaric acid-calcium ion chelate approaches the surface of the sodium polystyrene sulfonate microspheres, compared with free calcium ions, it can transfer calcium ions to the active sites on the microsphere surface more efficiently, thus significantly increasing the calcium loading rate. In addition, the chelation of tartaric acid and calcium ions can effectively prevent the formation of calcium precipitates in the solution, maintain the active state of calcium ions, increase the probability of their combination with the sulfonate ions on the microsphere surface, and promote the trans-calcium reaction to proceed more fully.

[0031] Preferably, before the calcium chloride solution is used, polyaspartic acid is added for mixing, and the mass fraction of polyaspartic acid in the calcium chloride solution is 0.05% - 0.4%.

[0032] Beneficial effects: Polyaspartic acid has a strong chelating ability for calcium ions and can form relatively stable chelates. It helps to disperse calcium ions evenly in the solution, promotes the full reaction of sodium polystyrene sulfonate and calcium chloride, and improves the conversion rate of calcium polystyrene sulfonate. In addition, the functional groups on the polyaspartic acid molecule can interact with the functional groups on the microsphere surface, further changing the properties of the microsphere surface and making it more conducive to the loading of calcium ions.

[0033] In the second aspect, the present application provides calcium polystyrene sulfonate prepared by the above method for preparing calcium polystyrene sulfonate.

[0034] To sum up, the present application has the following beneficial effects: 1. The present application uses an aqueous dispersion of zeolite to pretreat sodium polystyrene sulfonate, which can displace some sodium ions through ion exchange, reduce the shielding effect of sodium ions on sulfonic acid groups, expose more active sites of sulfonic acid groups, and thus more easily combine with calcium ions in subsequent reactions, increasing the calcium loading amount; at the same time, the gradual calcium conversion from low-concentration to high-concentration calcium chloride is adopted, making the exchange uniform, which not only improves the calcium loading rate in calcium polystyrene sulfonate, but also improves the product quality and performance consistency, and enhances the purity and yield.

[0035] 2. Before the use of the sodium polystyrene sulfonate microspheres in this application, they are successively washed with water, subjected to gradient oxidation, two-stage pickling, alcohol washing, and alkali washing. Among them, gradient oxidation realizes rapid oxidation, and two-stage pickling, etc. complete fine purification, constructing a two-stage impurity removal system of "rapid oxidation - fine purification". This system can not only more effectively remove more impurities in the microspheres, maintain the original performance and structure of the microspheres, but also enable the pores originally blocked or occupied by impurities to be released or exposed, providing more channels and binding sites for the subsequent entry of calcium ions, thereby increasing the calcium ion loading rate.

[0036] 3. This application preferably uses ferric chloride to pretreat zeolite. Iron ions enter the lattice structure of zeolite through ion exchange, promoting ion exchange with sodium polystyrene sulfonate microspheres, so that more sodium ions can be displaced from the sodium polystyrene sulfonate microspheres, reducing the occupation of sulfonic acid groups by sodium ions, making sulfonic acid groups more likely to bind with calcium ions, thereby increasing the calcium ion loading amount. Description of the Drawings

[0037] Figure 1 is the standard infrared light spectrum of calcium polystyrene sulfonate; Figure 2 is the infrared light spectrum of calcium polystyrene sulfonate in Example 1. Detailed Embodiments

[0038] The following further elaborates on this application in conjunction with examples.

[0039] The raw materials of the examples and comparative examples of this application are all ordinary commercially available except as otherwise specified.

[0040] The particle size distribution of the sodium polystyrene sulfonate microspheres is 0.3 - 0.8 mm; The particle size distribution of 4A zeolite is 1 - 10 μm; The rinsing speed of the sodium hypochlorite solution is 5 - 10 mL / min, the rinsing speed of the hydrochloric acid solution is 10 - 15 mL / min, the rinsing speed of sodium hydroxide is 8 - 12 mL / min, the rinsing speed of purified water is 15 - 20 mL / min, and the rinsing speed of ethanol is 8 - 12 mL / min.

[0041] Example 1 This example provides a preparation method of calcium polystyrene sulfonate, including the following steps: S1: Put 100 g of sodium polystyrene sulfonate microspheres and 300 g of an aqueous dispersion of 4A zeolite with a mass fraction of 6% in a container, stir and mix evenly, heat up to 40 °C, stir and mix at a speed of 200 r / min for 5 h, filter, wash 3 times with purified water, and then wash 2 times with a calcium chloride solution with a mass fraction of 6% to obtain primary sodium polystyrene sulfonate microspheres; S2: Stir and mix the primary sodium polystyrene sulfonate microspheres evenly with 100 g of purified water to obtain the first suspension; simultaneously introduce the first suspension and 500 g of a calcium chloride solution with a mass fraction of 8% into a microchannel reactor for a calcification reaction for 20 min, filter, wash twice with purified water, and then stir and mix evenly with 100 g of purified water to obtain the second suspension; simultaneously introduce the second suspension and 300 g of a calcium chloride solution with a mass fraction of 12% into the microchannel reactor for a calcification reaction for 20 min, filter, wash twice with purified water, and then stir and mix evenly with 100 g of purified water to obtain the third suspension; simultaneously introduce the third suspension and 200 g of a calcium chloride solution with a mass fraction of 15% into the microchannel reactor for a calcification reaction for 8 min, filter, wash with purified water until the conductivity of the outlet water is less than 40 us / cm, transfer to a blast drying oven, dry at 60 °C to constant weight, and pulverize to obtain calcium polystyrene sulfonate.

[0042] Among them, the temperature of the microchannel reactor is 40 °C, the flow rate of the first suspension is 2.0 mL / min, and the flow rate of the calcium chloride with a mass fraction of 8% is 5.0 mL / min; the flow rate of the second suspension is 2.0 mL / min, and the flow rate of the calcium chloride with a mass fraction of 12% is 4.0 mL / min; the flow rate of the third suspension is 3.0 mL / min, and the flow rate of the calcium chloride with a mass fraction of 15% is 3.0 mL / min.

[0043] A preparation method for an aqueous dispersion of 4A zeolite includes the following steps: Stir and mix 0.72 g of polyethylene glycol evenly with 281.28 g of purified water, then add 18 g of 4A zeolite, and stir and mix evenly at a rotation speed of 800 r / min to obtain it.

[0044] In step S1, the sodium polystyrene sulfonate microspheres are pretreated through the following steps before use: Connect the supply pipe of purified water to the bottom inlet of the glass column, then premix 110 g of sodium polystyrene sulfonate microspheres with 500 g of purified water and transfer them into the glass column. Slowly open the purified water valve, control the purified water to rise at a speed of 1 - 2 cm per minute, and reversely wash the sodium polystyrene sulfonate microspheres in the glass column. After washing for 3 min, connect the nitrogen pipe to the gas inlet at the bottom of the glass column, slowly open the high-purity nitrogen valve, adjust the nitrogen flow rate to make the nitrogen form a uniform and moderate bubble flow in the glass column, continue gas stirring for 5 min, and then filter to obtain the water-washed microspheres; The washed microspheres are first rinsed with a sodium hypochlorite solution with a mass fraction of 0.3% for 20 min, then immersed in a sodium hypochlorite solution with a mass fraction of 0.2% for 40 min, filtered, rinsed with purified water for 10 min, then rinsed with a hydrochloric acid solution with a mass fraction of 4% for 30 min, and then immersed in a hydrochloric acid solution with a mass fraction of 3% for 5 h, filtered, rinsed with purified water until the effluent is neutral, rinsed with ethanol for 10 min, then immersed in ethanol for 6 h, filtered, rinsed with purified water until there is no obvious ethanol smell, then rinsed with a sodium hydroxide solution with a mass fraction of 4% for 10 min, and then immersed in a sodium hydroxide solution with a mass fraction of 3% for 150 min, washed with purified water until the effluent is neutral, filtered, transferred to a blast drying oven, and dried at 50 °C to constant weight to obtain the product.

[0045] Example 2 This example provides a method for preparing calcium polystyrene sulfonate, which includes the following steps: S1: 100 g of sodium polystyrene sulfonate microspheres and 400 g of an aqueous dispersion of 4A zeolite with a mass fraction of 10% are placed in a container, stirred and mixed evenly, heated to 50 °C, stirred and mixed at a rotation speed of 200 r / min for 4 h, filtered, washed 4 times with purified water, and then washed 3 times with a calcium chloride solution with a mass fraction of 7% to obtain primary sodium polystyrene sulfonate microspheres; S2: The primary sodium polystyrene sulfonate microspheres are stirred and mixed evenly with 100 g of purified water to obtain suspension one; suspension one and 600 g of a calcium chloride solution with a mass fraction of 10% are simultaneously introduced into a microchannel reactor for calcification reaction for 25 min, filtered, washed 2 times with purified water, and then stirred and mixed evenly with 100 g of purified water to obtain suspension two; suspension two and 400 g of a calcium chloride solution with a mass fraction of 13% are simultaneously introduced into a microchannel reactor for calcification reaction for 25 min, filtered, washed 2 times with purified water, and then stirred and mixed evenly with 100 g of purified water to obtain suspension three; suspension three and 300 g of a calcium chloride solution with a mass fraction of 17% are simultaneously introduced into a microchannel reactor for calcification reaction for 12 min, filtered, washed with purified water until the conductivity of the effluent is less than 40 us / cm, transferred to a blast drying oven, dried at 60 °C to constant weight, and pulverized to obtain calcium polystyrene sulfonate.

[0046] Among them, the temperature of the microchannel reactor is 50 °C, the flow rate of suspension one is 2.0 mL / min, and the flow rate of calcium chloride with a mass fraction of 10% is 5.0 mL / min; the flow rate of suspension two is 2.0 mL / min, and the flow rate of calcium chloride with a mass fraction of 13% is 4.0 mL / min; the flow rate of suspension three is 3.0 mL / min, and the flow rate of calcium chloride with a mass fraction of 17% is 3.0 mL / min.

[0047] A preparation method of an aqueous dispersion of 4A zeolite, comprising the following steps: Stir and mix 2 g of polyethylene glycol and 358 g of purified water evenly, then add 40 g of 4A zeolite, and stir and mix evenly at a rotation speed of 800 r / min to obtain the product.

[0048] In step S1, the polystyrene sulfonate microspheres are pretreated through the following steps before use: Connect the supply pipe of purified water to the bottom inlet of the glass column, then premix 110 g of polystyrene sulfonate microspheres with 400 g of purified water and transfer them into the glass column. Slowly open the purified water valve, control the purified water to rise at a speed of 1-2 cm per minute, and reversely wash the polystyrene sulfonate microspheres in the glass column. After washing for 5 min, connect the nitrogen pipe to the gas inlet at the bottom of the glass column, slowly open the high-purity nitrogen valve, adjust the nitrogen flow rate to make the nitrogen form a uniform and moderate bubble flow in the glass column, continuously stir with gas for 10 min, and then filter to obtain the water-washed microspheres; First, wash the water-washed microspheres with a sodium hypochlorite solution with a mass fraction of 0.4% for 15 min, then immerse them in a sodium hypochlorite solution with a mass fraction of 0.3% for 30 min, filter, wash with purified water for 15 min, first wash with a hydrochloric acid solution with a mass fraction of 5% for 25 min, then immerse them in a hydrochloric acid solution with a mass fraction of 4% for 4 h, filter, wash with purified water until the effluent is neutral, wash with ethanol for 12 min, then immerse them in ethanol for 7 h, filter, wash with purified water until there is no obvious ethanol smell, then wash with a sodium hydroxide solution with a mass fraction of 5% for 8 min, then immerse them in a sodium hydroxide solution with a mass fraction of 4% for 120 min, wash with purified water until the effluent is neutral, filter, transfer to a blast drying oven, and dry at 50 °C until constant weight to obtain the product.

[0049] Example 3 This example provides a preparation method of calcium polystyrene sulfonate, comprising the following steps: S1: Put 100 g of polystyrene sulfonate microspheres and 500 g of an aqueous dispersion of 4A zeolite with a mass fraction of 12% in a container, stir and mix evenly, heat up to 60 °C, stir and mix at a rotation speed of 200 r / min for 3 h, filter, wash with purified water 5 times, and then wash with a calcium chloride solution with a mass fraction of 8% 4 times to obtain primary polystyrene sulfonate microspheres; S2: Stir and mix the primary sodium polystyrene sulfonate microspheres evenly with 100 g of purified water to obtain suspension one; simultaneously introduce suspension one and 700 g of a calcium chloride solution with a mass fraction of 12% into a microchannel reactor, carry out a calcification reaction for 30 min, filter, wash twice with purified water, and then stir and mix evenly with 100 g of purified water to obtain suspension two; simultaneously introduce suspension two and 500 g of a calcium chloride solution with a mass fraction of 15% into a microchannel reactor, carry out a calcification reaction for 30 min, filter, wash twice with purified water, and then stir and mix evenly with 100 g of purified water to obtain suspension three; simultaneously introduce suspension three and 400 g of a calcium chloride solution with a mass fraction of 20% into a microchannel reactor, carry out a calcification reaction for 15 min, filter, wash with purified water until the conductivity of the outlet water is less than 40 us / cm, transfer to a blast drying oven, dry at 60 °C to constant weight, and pulverize to obtain calcium polystyrene sulfonate; Among them, the temperature of the microchannel reactor is 60 °C, the flow rate of suspension one is 2.0 mL / min, and the flow rate of the calcium chloride with a mass fraction of 12% is 5.0 mL / min; the flow rate of suspension two is 2.0 mL / min, and the flow rate of the calcium chloride with a mass fraction of 15% is 4.0 mL / min; the flow rate of suspension three is 3.0 mL / min, and the flow rate of the calcium chloride with a mass fraction of 20% is 3.0 mL / min.

[0050] A preparation method for an aqueous dispersion of 4A zeolite, comprising the following steps: Stir and mix 3.6 g of polyethylene glycol evenly with 436.4 g of purified water, then add 60 g of 4A zeolite, and stir and mix evenly at a rotation speed of 800 r / min to obtain the product.

[0051] In step S1, the sodium polystyrene sulfonate microspheres are pretreated through the following steps before use: Connect the supply pipeline of purified water to the bottom inlet of the glass column, then premix 110 g of sodium polystyrene sulfonate microspheres with 300 g of purified water and transfer them into the glass column. Slowly open the purified water valve, control the purified water to rise at a speed of 1 - 2 cm per minute, and reversely wash the sodium polystyrene sulfonate microspheres in the glass column. After washing for 8 min, connect the nitrogen pipeline to the gas inlet at the bottom of the glass column, slowly open the high-purity nitrogen valve, adjust the nitrogen flow rate to make the nitrogen form a uniform and moderate bubble flow in the glass column, continuously carry out gas stirring for 15 min, and then filter to obtain the water-washed microspheres; The washed microspheres are first rinsed with a sodium hypochlorite solution with a mass fraction of 0.4% for 15 min, then immersed in a sodium hypochlorite solution with a mass fraction of 0.2% for 40 min, filtered, rinsed with purified water for 20 min, then rinsed with a hydrochloric acid solution with a mass fraction of 6% for 15 min, and then immersed in a hydrochloric acid solution with a mass fraction of 5% for 3 h, filtered, rinsed with purified water until the effluent is neutral, rinsed with ethanol for 15 min, then immersed in ethanol for 8 h, filtered, rinsed with purified water until there is no obvious ethanol smell, then rinsed with a sodium hydroxide solution with a mass fraction of 6% for 5 min, and then immersed in a sodium hydroxide solution with a mass fraction of 5% for 90 min, washed with purified water until the effluent is neutral, filtered, transferred to a blast drying oven, and dried to constant weight at 50 °C to obtain the product.

[0052] Example 4 The difference between this example and Example 3 is as follows: Before use, the 4A zeolite undergoes the following pretreatment steps: Add 60 g of 4A zeolite to the reactor, then add 300 ml of ferric chloride solution, stir and mix at a speed of 800 r / min for 15 min to obtain a uniformly distributed suspension, heat up to 50 °C, continuously stir and mix for 7 h, centrifuge and separate, wash 4 times with purified water, then transfer to a blast drying oven and dry to constant weight at 70 °C to obtain the product.

[0053] In step S2, before use, tartaric acid is added to and stirred with the calcium chloride solution with a mass fraction of 12%, the calcium chloride solution with a mass fraction of 15%, and the calcium chloride solution with a mass fraction of 20%; the mass fraction of tartaric acid in the above calcium chloride solutions is 0.1%.

[0054] Among them, tartaric acid is added to the calcium chloride solution before passing through the microchannel reactor and stirred and mixed evenly.

[0055] Other conditions are the same as in Example 3.

[0056] Example 5 The difference between this example and Example 4 is as follows: The mass fraction of the aqueous dispersion of 4A zeolite is 15%.

[0057] The preparation method of the aqueous dispersion of 4A zeolite includes the following steps: Stir and mix 4.5 g of polyethylene glycol and 420.5 g of purified water evenly, then add 75 g of 4A zeolite, and stir and mix evenly at a speed of 800 r / min to obtain the product.

[0058] Before use, the 4A zeolite undergoes the following pretreatment steps: Add 75 g of 4A zeolite into the reactor, then add 750 ml of ferric chloride solution, stir and mix at a speed of 800 r / min for 15 min to obtain a suspension with uniform distribution. Heat up to 70 °C, continuously stir and mix for 5 h, perform centrifugal separation, wash 4 times with purified water, and then transfer it into a blast drying oven and dry at 70 °C until constant weight to obtain the product.

[0059] In step S2, before use, tartaric acid was added to the calcium chloride solution with a mass fraction of 12%, the calcium chloride solution with a mass fraction of 15%, and the calcium chloride solution with a mass fraction of 20% for stirring and mixing; the mass fraction of tartaric acid in the above calcium chloride solutions was 0.3% in each case.

[0060] Others are the same as in Example 4.

[0061] Example 6 The difference between this example and Example 5 is as follows: In step S2, before use, polyaspartic acid was added to the calcium chloride solution with a mass fraction of 12%, the calcium chloride solution with a mass fraction of 15%, and the calcium chloride solution with a mass fraction of 20% for stirring and mixing; The mass fraction of polyaspartic acid in the calcium chloride solution with a mass fraction of 12% was 0.05%, the mass fraction of polyaspartic acid in the calcium chloride solution with a mass fraction of 15% was 0.15%, and the mass fraction of polyaspartic acid in the calcium chloride solution with a mass fraction of 20% was 0.3%.

[0062] Others are the same as in Example 5.

[0063] Example 7 The difference between this example and Example 6 is as follows: In step S2, before use, polyaspartic acid was added to the calcium chloride solution with a mass fraction of 12%, the calcium chloride solution with a mass fraction of 15%, and the calcium chloride solution with a mass fraction of 20% for stirring and mixing; The mass fraction of polyaspartic acid in the calcium chloride solution with a mass fraction of 12% was 0.1%, the mass fraction of polyaspartic acid in the calcium chloride solution with a mass fraction of 15% was 0.2%, and the mass fraction of polyaspartic acid in the calcium chloride solution with a mass fraction of 20% was 0.4%.

[0064] Others are the same as in Example 6.

[0065] Comparative Example 1 This comparative example provides a preparation method of calcium polystyrene sulfonate, including the following steps: S1: Stir and mix the sodium polystyrene sulfonate microspheres evenly with 100 g of purified water to obtain suspension one; simultaneously introduce suspension one and 500 g of a calcium chloride solution with a mass fraction of 8% into a microchannel reactor, carry out a calcification reaction for 20 min, filter, wash twice with purified water, and then stir and mix evenly with 100 g of purified water to obtain suspension two; simultaneously introduce suspension two and 300 g of a calcium chloride solution with a mass fraction of 12% into the microchannel reactor, carry out a calcification reaction for 20 min, filter, wash twice with purified water, and then stir and mix evenly with 100 g of purified water to obtain suspension three; simultaneously introduce suspension three and 200 g of a calcium chloride solution with a mass fraction of 15% into the microchannel reactor, carry out a calcification reaction for 8 min, filter, wash with purified water until the conductivity of the effluent is less than 40 us / cm, transfer to a blast drying oven, dry at 60 °C to constant weight, and pulverize to obtain calcium polystyrene sulfonate.

[0066] Among them, the temperature of the microchannel reactor is 40 °C, the flow rate of suspension one is 2.0 mL / min, and the flow rate of calcium chloride with a mass fraction of 5% is 5.0 mL / min; the flow rate of suspension two is 2.0 mL / min, and the flow rate of calcium chloride with a mass fraction of 15% is 4.0 mL / min; the flow rate of suspension three is 3.0 mL / min, and the flow rate of calcium chloride with a mass fraction of 20% is 3.0 mL / min.

[0067] In step S1, the sodium polystyrene sulfonate microspheres are pretreated through the following steps before use: Connect the supply pipe of purified water to the bottom inlet of the glass column, then premix 110 g of sodium polystyrene sulfonate microspheres with 500 g of purified water and transfer them into the glass column. Slowly open the purified water valve, control the purified water to rise at a speed of 1 - 2 cm per minute, and reversely wash the sodium polystyrene sulfonate microspheres in the glass column. After washing for 3 min, connect the nitrogen pipe to the gas inlet at the bottom of the glass column, slowly open the high-purity nitrogen valve, adjust the nitrogen flow rate to form a uniform and moderate bubble flow of nitrogen in the glass column, continuously stir with gas for 5 min, filter, and obtain the water-washed microspheres; The washed microspheres are first rinsed with a sodium hypochlorite solution with a mass fraction of 0.2% for 30 min, then immersed in a sodium hypochlorite solution with a mass fraction of 0.1% for 60 min, filtered, rinsed with purified water for 10 min, then rinsed with a hydrochloric acid solution with a mass fraction of 4% for 30 min, and then immersed in a hydrochloric acid solution with a mass fraction of 3% for 5 h, filtered, rinsed with purified water until the effluent is neutral, rinsed with ethanol for 10 min, then immersed in ethanol for 6 h, filtered, rinsed with purified water until there is no obvious ethanol smell, then rinsed with a sodium hydroxide solution with a mass fraction of 4% for 10 min, and then immersed in a sodium hydroxide solution with a mass fraction of 3% for 150 min, washed with purified water until the effluent is neutral, filtered, transferred to a forced-air drying oven, dried at 50 °C to constant weight, and thus obtained.

[0068] Comparative Example 2 The difference between this comparative example and Example 1 is that: In step S1, 100 g of sodium polystyrene sulfonate microspheres and 300 g of an aqueous dispersion of 4A zeolite with a mass fraction of 6% are placed in a container, stirred and mixed evenly, heated to 40 °C, stirred and mixed at a rotation speed of 200 r / min for 5 h, filtered, and washed 5 times with purified water to obtain primary sodium polystyrene sulfonate microspheres; Others are the same as in Example 1.

[0069] Comparative Example 3 The difference between this comparative example and Example 1 is that: In step S2, the primary sodium polystyrene sulfonate microspheres and 300 g of purified water are stirred and mixed evenly to obtain a suspension. The suspension and 1000 g of a calcium chloride solution with a mass fraction of 15% are simultaneously introduced into a microchannel reactor for calcification reaction for 48 min, filtered, and washed 2 times with purified water until the conductivity of the effluent is less than 40 us / cm, transferred to a forced-air drying oven, dried at 60 °C to constant weight, and pulverized to obtain calcium polystyrene sulfonate; Others are the same as in Example 1.

[0070] Comparative Example 4 The difference between this comparative example and Example 1 is that: Before use, the sodium polystyrene sulfonate microspheres in step S1 are subjected to the following pretreatment steps: Connect the supply pipeline of purified water to the bottom inlet of the glass column. Then premix 110 g of sodium polystyrene sulfonate microspheres with 500 g of purified water and transfer them into the glass column. Slowly open the purified water valve, control the purified water to rise at a speed of 1 - 2 cm per minute, and reverse - wash the sodium polystyrene sulfonate microspheres in the glass column. After washing for 3 min, connect the nitrogen pipeline to the gas inlet at the bottom of the glass column. Slowly open the high - purity nitrogen valve, adjust the nitrogen flow rate to form a uniform and moderate bubble flow of nitrogen in the glass column. After continuous gas stirring for 5 min, filter to obtain the water - washed microspheres; Wash the water - washed microspheres with a 0.25% sodium hypochlorite solution for 20 min, then immerse them in a 0.25% sodium hypochlorite solution for 40 min, filter, wash with purified water for 10 min, first wash with a 3.5% hydrochloric acid solution for 30 min, then immerse in a 3.5% hydrochloric acid solution for 5 h, filter, wash with purified water until the effluent is neutral, wash with ethanol for 10 min, then immerse in ethanol for 6 h, filter, wash with purified water until there is no obvious ethanol smell, then wash with a 3.5% sodium hydroxide solution for 10 min, then immerse in a 3.5% sodium hydroxide solution for 150 min, wash with purified water until the effluent is neutral, filter, transfer to a blast drying oven, and dry at 50 °C to constant weight to obtain the product.

[0071] Others are the same as in Example 1.

[0072] Performance detection test Use the EDTA titration method to measure the calcium content in the calcium polystyrene sulfonate prepared in Examples 1 - 7 and Comparative Examples 1 - 4 respectively, and calculate the calcium loading rate for each sample; according to the ion - exchange stoichiometric relationship (the potassium - calcium exchange ratio is 2:1), record the exchange amount of the calcium polystyrene sulfonate prepared in Examples 1 - 7 and Comparative Examples 1 - 4 in the potassium chloride solution respectively to obtain the potassium exchange amount of each sample. The specific results are shown in Table 1. Among them, the molecular weight of potassium chloride is 74.55, and the molecular weight of potassium is 39.10.

[0073] Table 1 Performance detection of calcium polystyrene sulfonate prepared in Examples 1 - 7 and Comparative Examples 1 - 4

[0074] Figure 1 From the Japanese Pharmacopoeia, combined with Figures 1 to 2 Analysis of Example 1 shows that: The absorption peak positions of the calcium polystyrene sulfonate prepared in Example 1 are close to those of the standard spectrum in multiple key wavenumber ranges. For example, in the range of 3000 - 3100 cm -1The absorption peak that appears nearby can be attributed to the stretching vibration of C-H on the benzene ring, indicating the presence of a benzene ring structure in the sample; the absorption peak at 1000 - 1200 cm -1 corresponds to the stretching vibration of S-O in the sulfonic acid group, indicating that the sample has the structural characteristics of calcium sulfonate. These similar absorption peaks show that the main functional groups of the sample are consistent with those of the standard product, preliminarily proving that the sample is calcium polystyrene sulfonate from the perspective of infrared spectroscopy.

[0075] Analysis of Example 1 and Comparative Examples 1 - 4 shows that by pretreating sodium polystyrene sulfonate microspheres with 4A zeolite, the chemical environment or microstructure of the microspheres is changed, providing more active sites or more favorable binding methods for the subsequent loading of calcium ions, thereby increasing the calcium loading rate. The calcium conversion reaction is carried out in a gradient-increasing form, avoiding drastic changes in the ion concentration in the reaction system, enabling calcium ions to bind more uniformly and stably with the sulfonate ions in sodium polystyrene sulfonate, reducing precipitation or side reactions caused by excessive local ion concentration, and being beneficial to increasing the calcium loading rate.

[0076] Analysis of Examples 1 - 3 shows that by optimizing the ratios of the components, the calcium polystyrene sulfonate prepared all has a good calcium loading rate.

[0077] Analysis of Examples 3 - 7 shows that by pretreating 4A zeolite with ferric chloride, when subsequently pretreating sodium polystyrene sulfonate microspheres, the chemical environment or microstructure of the microspheres is further changed, providing more active sites or more favorable binding methods for the subsequent loading of calcium ions, thereby increasing the calcium loading rate. Adding tartaric acid and polyaspartic acid to the calcium chloride solution can optimize the environmental system of the calcium conversion reaction, synergistically with the effect of pretreating 4A zeolite with ferric chloride, and further promoting the subsequent loading of calcium ions.

[0078] This specific embodiment is only an interpretation of the present application and is not a limitation thereto. Those skilled in the art can make modifications without creative contributions to this embodiment as needed after reading this specification, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A method for preparing calcium polystyrene sulfonate, characterized in that: The steps include: S1: Mix the sodium polystyrene sulfonate microspheres and the aqueous dispersion of zeolite in a mass ratio of 1:(3-5), heat to 40-60°C, mix for 3-5 hours, separate the solid and liquid, and wash to obtain primary sodium polystyrene sulfonate microspheres; S2: Primary sodium polystyrene sulfonate microspheres are prepared into suspension 1, and suspension 1 and a calcium chloride solution with a mass fraction of 8% to 12% are introduced into a microchannel reactor at the same time, react for 20 to 30 minutes, separate the solid and liquid, wash, and prepare suspension 2, and suspension 2 and a calcium chloride solution with a mass fraction of 12% to 15% are introduced into a microchannel reactor at the same time, react for 20 to 30 minutes, separate the solid and liquid, wash, and prepare suspension 3, and suspension 3 and a calcium chloride solution with a mass fraction of 15% to 20% are introduced into a microchannel reactor at the same time, react for 8 to 15 minutes, separate the solid and liquid, wash, dry, and crush to obtain calcium polystyrene sulfonate; The mass fraction of zeolite in the aqueous dispersion is 6% to 15%.

2. The method for preparing calcium polystyrene sulfonate according to claim 1, characterized in that: The mass ratio of the sodium polystyrene sulfonate microspheres, the calcium chloride solution with a mass fraction of 8% to 12%, the calcium chloride solution with a mass fraction of 12% to 15%, and the calcium chloride solution with a mass fraction of 15% to 20% is 1:(5-7):(3-5):(2-4).

3. The method for preparing calcium polystyrene sulfonate according to claim 1, characterized in that: In step S1, the washing is first performed with water for 3 to 5 times, and then with a calcium chloride solution with a mass fraction of 6% to 8% for 2 to 4 times.

4. The method for preparing calcium polystyrene sulfonate according to claim 1, characterized in that: The sodium polystyrene sulfonate microspheres are subjected to the following pretreatment steps before use: The sodium polystyrene sulfonate microspheres are sequentially washed with water, oxidized, acid washed, alcohol washed, and alkaline washed until neutral, and dried to obtain the microspheres.

5. The method for preparing calcium polystyrene sulfonate according to claim 4, characterized in that: The oxidation adopts gradient oxidation, first washing with a sodium hypochlorite solution with a mass fraction of 0.3% to 0.5% for 10 to 20 minutes, then immersing in a sodium hypochlorite solution with a mass fraction of 0.2% to 0.4% for 20 to 40 minutes, and then solid-liquid separation and washing.

6. The method for preparing calcium polystyrene sulfonate according to claim 1, characterized in that: The zeolite is subjected to the following pretreatment steps before use: Disperse zeolite in ferric chloride solution, heat to 50-70°C, soak and mix for 5-7 hours, separate solid and liquid, wash, and dry to obtain; The concentration of the ferric chloride solution is 0.1-0.3 mol / L.

7. The method for preparing calcium polystyrene sulfonate according to claim 6, characterized in that: The mass volume ratio of the zeolite to the ferric chloride solution is 1 g: (5-10) ml.

8. The method for preparing calcium polystyrene sulfonate according to claim 6, characterized in that: In step S2, before the calcium chloride solution is used, tartaric acid is added for mixing, and the mass fraction of the tartaric acid in the calcium chloride solution is 0.1% to 0.3%.

9. The method for preparing calcium polystyrene sulfonate according to claim 1, characterized in that: In step S2, before using the calcium chloride solution, polyaspartic acid is added for mixing, and the mass fraction of the polyaspartic acid in the calcium chloride solution is 0.05% to 0.4%.

10. Calcium polystyrene sulfonate obtained by the method for preparing calcium polystyrene sulfonate according to any one of claims 1 to 9.

Images