A granular ion sieve, and a method of making and using the same

Abstract

The application provides a granular ion sieve and a preparation method and application thereof, and the preparation method comprises the following steps: (1) dissolving a polymer monomer in an organic solvent to obtain an oil phase, mixing the oil phase with ion sieve powder, and performing a prepolymerization reaction and slurry under stirring to obtain a prepolymer; (2) mixing the prepolymer obtained in the step (1) with an aqueous phase containing a high molecular dispersant, and performing a suspension polymerization reaction to obtain the granular ion sieve. Through the method of simultaneously performing the prepolymerization and the slurry, the ion sieve powder can be thoroughly mixed with the polymer monomer, and the ion sieve powder is not easy to diffuse into the aqueous phase in the polymerization process, the process stability and product performance are improved, and the granular ion sieve prepared has a balling rate of greater than 70% in a qualified particle size range 。

Description

Technical Field

[0001] This invention belongs to the field of resin materials technology, specifically relating to a granular ion sieve, its preparation method, and its application. Background Technology

[0002] Ion sieves are widely studied and used nanoscale powder adsorbents, possessing advantages such as high adsorption capacity, fast adsorption rate, and good selective adsorption. Manganese-based ion sieve precursors have a cubic crystal structure; after acid activation, lithium ions are replaced by hydrogen ions. These sites possess specific adsorption capabilities for lithium ions, with theoretical adsorption capacities varying depending on the lithium content in the precursor, reaching a maximum of 44 mg / g. Adsorption can reach equilibrium within a few hours. However, ion sieves have been difficult to apply industrially. Powdered ion sieves are prone to clogging when used directly and must be granulated into micron or millimeter-sized spheres for practical use. However, the granulation process significantly reduces the adsorption performance of the ion sieve, and severe deformation during repeated use further affects mass transfer and may even cause detachment.

[0003] Granulation is mostly achieved through bonding, the most typical example being polyvinyl chloride (PVC). By mixing ion sieves, binders, and organic solvents and dispersing them into spheres in an aqueous phase, the resulting adsorbent has an adsorption equilibrium time of more than two days and exhibits significant detachment upon repeated use. In recent years, reports have emerged of polymer granulation ("Lithium ion recovery from brine using granulated polyacrylamide–MnO2 ion-sieve", Xiao J, et al., Chemical Engineering Journal, 2015). Adsorbents are obtained by polymerizing a mixture of powder and monomer phases, and their performance is improved compared to the bonding method. However, current polymerization granulation uses hydrophilic monomers such as acrylamide, synthesized through reverse suspension polymerization. This is because ion sieve powders are relatively hydrophilic, and traditional suspension polymerization causes them to diffuse severely in the aqueous phase, making them unable to be immobilized. There are three main problems with this reverse suspension polymerization: First, when hydrophilic polymers are used in the aqueous phase, their volume changes with pH changes, causing severe deformation of the adsorbent and affecting mass transfer; second, currently reported hydrophilic polymers cannot obtain highly cross-linked structures, limiting their strength and making them unable to withstand excessively high pressures and temperatures; and third, hydrophilic materials swell and detach severely in water treatment, resulting in poor reusability.

[0004] CN105195070A discloses a method for preparing molecular sieve microspheres: A slurry is obtained by mixing aluminum gel with molecular sieve powder, heating the slurry to 65-90℃, and adding gellan gum; the slurry is then added to an oil phase at 80-100℃ and stirred at high speed, cooled, and a cationic solution is added with continued stirring to obtain gel microspheres; the gel microspheres are washed, dried, and calcined to obtain molecular sieve microspheres. This method has advantages such as fast molding speed, pollution-free preparation process, and low production cost, and the operation steps are simple, making it easy to achieve industrial production; the product has good wear resistance and fluidization properties, and the particle size can meet the requirements of various reactors. However, swelling is prone to occur during use, making it difficult to meet the application requirements in water treatment.

[0005] CN115364783A discloses a hierarchical lithium-ion sieve microsphere. The preparation method of the hierarchical lithium-ion sieve microsphere includes the following steps: Ti3C2MXene is stirred evenly with hydrogen peroxide solution and sodium hydroxide solution, and subjected to hydrothermal reaction to obtain sodium titanate; the sodium titanate is placed in hydrochloric acid solution for reaction, and after the reaction is completed, it is washed and dried to obtain nanoribbons; then the nanoribbons are ultrasonically mixed with lithium hydroxide solution, subjected to a second hydrothermal reaction, and after the reaction is completed, it is washed and dried to obtain Li4Ti5O. 12 Li4Ti5O 12 The lithium-ion sieve precursor was obtained by calcination; the lithium-ion sieve precursor was placed in hydrochloric acid solution and then dried to obtain hierarchical lithium-ion sieve microspheres, which are easily diffused in water.

[0006] Existing ion sieves suffer from problems such as easy swelling during use, easy loss during water treatment, and easy diffusion in water. Therefore, developing a granular ion sieve that is not prone to swelling, has excellent adsorption performance, and a preparation method that is not easily lost during water treatment and does not easily diffuse into the aqueous phase during polymerization is an urgent problem to be solved in this field. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a granular ion sieve, its preparation method, and its application. In the preparation method, the oil phase is prepolymerized separately, and the time is controlled to avoid the oil phase from rapidly polymerizing on its own. During the polymerization process, it is not easy to diffuse into the aqueous phase. The resulting granular ion sieve has a relatively uniform particle size, is not agglomerated, and the synthesis process is stable and repeatable. It exhibits high adsorption performance and reusability in lithium adsorption.

[0008] To achieve this objective, the present invention adopts the following technical solution:

[0009] In a first aspect, the present invention provides a method for preparing a granular ion sieve, the method comprising the following steps:

[0010] (1) The polymer monomer is dissolved in an organic solvent to obtain an oil phase, the oil phase is mixed with ion sieve powder, and a prepolymerization reaction and slurrying are carried out under stirring to obtain a prepolymer;

[0011] (2) The prepolymer obtained in step (1) is mixed with an aqueous phase containing a polymeric dispersant and subjected to a suspension polymerization reaction to obtain the granular ion sieve.

[0012] Preferably, the polymerizing monomer includes monoolefin monomers and / or crosslinking monomers.

[0013] Preferably, the polymerizing monomer includes any one or a combination of at least two of styrene, styrene-based modified monomers, crosslinking monomers, or methacrylate monomers.

[0014] Preferably, by simultaneously performing prepolymerization and slurrying, the ion sieve powder and the polymer monomer can be thoroughly mixed, making it less likely to diffuse into the aqueous phase during the suspension polymerization reaction, thereby improving process stability and product performance.

[0015] Preferably, the styrene-based modified monomer includes chloromethylstyrene.

[0016] Preferably, the crosslinking monomer comprises divinylbenzene.

[0017] Preferably, the methacrylate monomers include methyl methacrylate and / or ethylene glycol methacrylate.

[0018] Preferably, the mass of the polymeric monomer is 100%, and the mass of the crosslinking monomer is 0-100%, for example, it can be 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0019] Preferably, the oil phase in step (1) further includes an initiator and a pore-forming agent.

[0020] Preferably, the initiator is an oil-soluble initiator.

[0021] Preferably, the initiator comprises benzoyl peroxide.

[0022] Preferably, the amount of the initiator is 0.5-3% of the mass of the polymerizing monomer, for example, it can be 0.5%, 0.7%, 0.9%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0023] Preferably, the pore-forming agent is an oil-soluble inert substance.

[0024] Preferably, the pore-forming agent comprises liquid wax and / or white oil.

[0025] Preferably, the amount of the porogen is 1-100% of the mass of the polymer monomer, for example, it can be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0026] Preferably, the organic solvent is an aliphatic short-chain ester or a long-chain alcohol.

[0027] Preferably, the organic solvent includes any one or a combination of at least two of ethyl acetate, isooctanol, butyl acetate, or toluene.

[0028] Preferably, the amount of organic solvent used is 1-100% of the mass of the polymerized monomer, for example, it can be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, 100%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0029] Preferably, by using organic solvents instead of aromatic hydrocarbon solvents used in traditional styrene polymerization, the polarity of the oil phase is enhanced, which helps to retain the ion sieve powder.

[0030] Preferably, the amount of ion sieve powder used in step (1) is 1-50% of the mass of the polymer monomer, for example, it can be 1%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0031] Preferably, the ion sieve powder includes a manganese-based ion sieve.

[0032] Preferably, the particle size of the ion sieve powder is <1μm, for example, it can be 0.1μm, 0.2μm, 0.3μm, 0.4μm, 0.5μm, 0.6μm, 0.7μm, 0.8μm, 0.9μm, 0.99μm, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0033] Preferably, the stirring speed in step (1) is 200-600 r / min, for example, it can be 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, 450 r / min, 500 r / min, 550 r / min, 600 r / min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0034] Preferably, the stirring in step (1) is electromagnetic stirring.

[0035] Preferably, the reaction temperature of the prepolymerization reaction in step (1) is 65-80℃, for example, it can be 65℃, 68℃, 70℃, 72℃, 75℃, 78℃, 80℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0036] Preferably, the reaction time of the prepolymerization reaction in step (1) is 30-90 min, for example, it can be 30 min, 35 min, 40 min, 45 min, 50 min, 55 min, 60 min, 65 min, 70 min, 75 min, 80 min, 85 min, 90 min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0037] Preferably, the oil phase is prepolymerized separately, and controlling the time can prevent the oil phase from polymerizing too quickly.

[0038] Preferably, the volume ratio of the oil phase to the water phase is 1:(2-6), for example, it can be 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0039] Preferably, the polymeric dispersant comprises polyvinyl alcohol.

[0040] Preferably, the mass concentration of the polymeric dispersant in the aqueous phase in step (2) is 0.5-3%, for example, it can be 0.5%, 0.8%, 1%, 1.2%, 1.5%, 1.8%, 2%, 2.2%, 2.5%, 2.8%, 3%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0041] Preferably, the polymeric dispersant can act as a surfactant to stabilize the small droplets formed in the oil phase.

[0042] Preferably, the aqueous phase in step (2) also includes inorganic salts.

[0043] Preferably, the mass concentration of inorganic salts in the aqueous phase in step (2) is 2-10%, for example, it can be 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0044] Preferably, the inorganic salt includes sodium chloride.

[0045] Preferably, the inorganic salt can reduce the solubility of polymeric monomers in the aqueous phase and can also adjust the density of the aqueous phase.

[0046] Preferably, the suspension polymerization reaction in step (2) is carried out under stirring conditions, and more preferably under electromagnetic stirring conditions.

[0047] Preferably, the stirring speed is 100-400 r / min, for example, it can be 100 r / min, 150 r / min, 200 r / min, 250 r / min, 300 r / min, 350 r / min, 400 r / min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0048] Preferably, the reaction temperature of the suspension polymerization reaction in step (2) is 75-90℃, for example, it can be 75℃, 78℃, 80℃, 82℃, 85℃, 88℃, 90℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0049] Preferably, the reaction time of the suspension polymerization reaction in step (2) is 5-10h, for example, it can be 5h, 5.5h, 6h, 6.5h, 7h, 7.5h, 8h, 8.5h, 9h, 9.5h, 10h, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0050] Preferably, the prepolymer is poured into the aqueous phase and dispersed at an appropriate stirring speed. Adjusting the speed of the electromagnetic stirring can effectively control the particle size of the ion sieve.

[0051] Preferably, the preparation method further includes post-processing.

[0052] Preferably, the post-processing includes washing, natural drying, extraction, and sieving.

[0053] Preferably, the cleaning includes cleaning with hot water and ethanol.

[0054] Preferably, the natural drying time is 4-10 hours, for example, 4 hours, 4.5 hours, 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0055] Preferably, the soxhlet extraction is performed by washing with petroleum ether in a Soxhlet extractor.

[0056] Preferably, the extraction time is 5-8 hours, for example, it can be 5 hours, 5.5 hours, 6 hours, 6.5 hours, 7 hours, 7.5 hours, 8 hours, 8.5 hours, 9 hours, 9.5 hours, 10 hours, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0057] Preferably, the sieving is performed in two layers of mesh.

[0058] Preferably, the preparation method specifically includes the following steps:

[0059] (1) A polymer initiator, a pore-forming agent and an organic solvent are mixed to obtain an oil phase. The oil phase is then mixed with ion sieve powder and subjected to a prepolymerization reaction and slurrying under stirring to obtain a prepolymer.

[0060] The polymerization monomers include monoolefin monomers and / or crosslinking monomers, the initiator is an oil-soluble initiator, the porogen is an oil-soluble inert substance, the organic solvent is an aliphatic short-chain lipid or a long-chain alcohol, the particle size of the ion sieve powder is <1μm, the reaction temperature of the prepolymerization reaction is 65-80℃, and the reaction time is 30-90min.

[0061] (2) The prepolymer obtained in step (1) is mixed with an aqueous phase containing a polymeric dispersant and an inorganic salt, and a suspension polymerization reaction is carried out to obtain the granular ion sieve;

[0062] The volume ratio of the oil phase to the water phase is 1:(2-6); the mass concentration of the polymeric dispersant in the water phase is 0.5-3%; the mass concentration of the inorganic salt in the water phase is 2-10%; the reaction temperature of the suspension polymerization reaction is 78-90℃, and the reaction time is 5-10h.

[0063] In a second aspect, the present invention provides a granular ion sieve, which is prepared by the preparation method described in the first aspect.

[0064] Preferably, the particle size of the granular ion sieve is 300-1000 μm, for example, it can be 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, 550 μm, 600 μm, 650 μm, 700 μm, 750 μm, 800 μm, 850 μm, 900 μm, 950 μm, 1000 μm, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0065] Preferably, the water content of the granular ion sieve is 50-65 wt%, for example, it can be 50 wt%, 52 wt%, 54 wt%, 56 wt%, 58 wt%, 60 wt%, 62 wt%, 64 wt%, 65 wt%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0066] Thirdly, the present invention provides an application of the granular ion sieve as described in the second aspect in an adsorbent.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] The method for preparing granular ion sieves provided by this invention produces well-formed, black, non-adhesive spherical ion sieves with controllable particle size and high strength. The granular ion sieves obtained through forward suspension polymerization are not easily detached during repeated use. The prepolymerization process is stable, preventing severe diffusion of the ion sieve into the aqueous phase. By simultaneously performing prepolymerization and slurrying, the ion sieve powder and polymer monomers can be thoroughly mixed, preventing diffusion into the aqueous phase during polymerization, thus improving process stability and product performance. The prepared granular ion sieves have a sphericity greater than 70% in the particle size range of 250-850 μm, a water content of 53.34-62.46 wt%, a saturated adsorption capacity of 10.3-16.3 mg / g, an adsorption equilibrium time of 10-14 h, and after 10 repetitions, the saturated adsorption capacity is 9.8-15.2 mg / g, with a saturated adsorption equilibrium time of 10-14 h after 10 repetitions. Detailed Implementation

[0069] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0070] The experimental materials used in the embodiments and comparative examples of this invention are as follows:

[0071] (1) Manganese-based ion sieve (preparation method is the same as in the literature, "Synthesis of granulated H4Mn5O 12 / chitosan with improved stability by a novel cross-linking strategy for lithium adsorption from aqueous solutions", Ding W, et al. [J]. Chemical Engineering Journal, 2021, 426: 131689.);

[0072] (2) Titanium-based ion sieve (preparation method is the same as in the literature, "Synthesis of Polyporous Ion-Sieve and Its Application for Selective Recovery of Lithium from Geothermal Water", Lin H, et al. [J]. ACS Applied Materials & Interfaces, 2019, 11(29).);

[0073] (3) Polyvinyl alcohol, brand name 1788, manufacturer Aladdin;

[0074] Example 1

[0075] A method for preparing a granular ion sieve, the specific preparation method includes the following steps:

[0076] Dissolve 5g of sodium chloride and 1g of polyvinyl alcohol in 100mL of water and stir in a 250mL three-necked flask. Heat to 78℃ to obtain an aqueous phase. Weigh out 10g of styrene, 2g of divinylbenzene, 0.12g of benzoyl peroxide, 10g of ethyl acetate, and 10g of liquid wax. Mix them thoroughly to obtain an oil phase. Add 6g of manganese-based ion sieve and heat in a water bath to 78℃ under electromagnetic stirring at 500r / min for 90min to obtain a prepolymer. Add the prepolymer to the aqueous phase and adjust the stirring speed to 200r / min to obtain a sol with a particle size of about 500μm. React at 78℃ for 8 hours. Wash the product with hot water until no foam is present, wash away excess water with ethanol, and allow to dry naturally for 6 hours. Extract with petroleum ether for 6 hours to obtain granular ion sieves. Sieve using 450μm and 550μm mesh to obtain the final product.

[0077] Example 2

[0078] A method for preparing a granular ion sieve, the specific preparation method includes the following steps:

[0079] Dissolve 5g of sodium chloride and 2g of polyvinyl alcohol in 200mL of water, stir in a 500mL three-necked flask, and heat to 78℃ to obtain an aqueous phase. Weigh out 15g of styrene, 15g of divinylbenzene, 0.2g of benzoyl peroxide, and 15g of butyl acetate, mix them evenly to obtain an oil phase, add 15g of manganese-based ion sieve, and heat in a water bath to 78℃ under electromagnetic stirring at 500r / min for 70min to obtain a prepolymer. Add the prepolymer to the aqueous phase, adjust the stirring speed to 300r / min to obtain a sol with a particle size of about 400μm, react at 85℃ for 8 hours, wash the product with hot water until no foam is present, wash away excess water with ethanol, air dry for 6 hours, and then extract with petroleum ether for 6 hours to obtain granular ion sieves. Sieve through 350μm and 450μm mesh to obtain the final product.

[0080] Example 3

[0081] A method for preparing a granular ion sieve, the specific preparation method includes the following steps:

[0082] Dissolve 5g of sodium chloride and 0.5g of polyvinyl alcohol in 100mL of water, stir in a 250mL three-necked flask, and heat to 78℃ to obtain an aqueous phase. Weigh 15g of divinylbenzene, 0.15g of benzoyl peroxide, and 5g of ethyl acetate, mix thoroughly to obtain an oil phase, add 7.5g of titanium-based ion sieve, and heat in a water bath to 78℃ under electromagnetic stirring at 500r / min for 30min to obtain a prepolymer. Add the prepolymer to the aqueous phase, adjust the stirring speed to 400r / min to obtain a sol with a particle size of approximately 800μm, and react at 85℃ for 8 hours. Wash the product with hot water until no foam remains, wash away excess water with ethanol, air dry for 6 hours, and then extract with petroleum ether for 6 hours to obtain granular ion sieves. Sieve through 750μm and 850μm mesh to obtain the final product.

[0083] Example 4

[0084] A method for preparing a granular ion sieve, the specific preparation method includes the following steps:

[0085] Dissolve 5g of sodium chloride and 1g of polyvinyl alcohol in 100mL of water and stir in a 250mL three-necked flask. Heat to 78℃ to obtain an aqueous phase. Weigh out 15g of chloromethylstyrene, 5g of divinylbenzene, 0.2g of benzoyl peroxide, and 10g of isooctanol. Mix them thoroughly to obtain an oil phase. Add 10g of manganese-based ion sieve and heat in a water bath to 78℃ under electromagnetic stirring at 500r / min for 90min to obtain a prepolymer. Add the prepolymer to the aqueous phase and adjust the stirring speed to 400r / min to obtain a sol with a particle size of about 300μm. React at 80℃ for 8 hours. Wash the product with hot water until no foam is present, wash away excess water with ethanol, and allow to dry naturally for 6 hours. Extract with petroleum ether for 6 hours to obtain granular ion sieve. Sieve through 250μm and 350μm mesh to obtain the final product.

[0086] Example 5

[0087] A method for preparing a granular ion sieve, the specific preparation method includes the following steps:

[0088] Dissolve 5g of sodium chloride and 1g of polyvinyl alcohol in 100mL of water and stir in a 250mL three-necked flask. Heat to 78℃ to obtain an aqueous phase. Weigh out 10g of styrene, 2g of divinylbenzene, 0.12g of benzoyl peroxide, and 20g of ethyl acetate. Mix them thoroughly to obtain an oil phase. Add 6g of manganese ion sieve and heat in a water bath to 78℃ under electromagnetic stirring at 500r / min. React for 90min to obtain a prepolymer. Add the prepolymer to the aqueous phase and adjust the stirring speed to 200r / min to obtain a sol with a particle size of about 500μm. React at 78℃ for 8 hours. Only random polymers with poor spherical shape can be obtained. The amount of organic solvent used exceeds the preferred range. The polymer swells excessively after molding and cannot be solidified into spheres.

[0089] Example 6

[0090] A method for preparing a granular ion sieve, the specific preparation method includes the following steps:

[0091] Dissolve 5g of sodium chloride and 1g of polyvinyl alcohol in 100mL of water and stir in a 250mL three-necked flask. Heat to 78℃ to obtain an aqueous phase. Weigh out 10g of styrene, 2g of divinylbenzene, 0.12g of benzoyl peroxide, 10g of ethyl acetate, and 10g of liquid wax. Mix them evenly to obtain an oil phase. Add 6g of manganese ion sieve and heat in a water bath to 78℃ under electromagnetic stirring at 500r / min for 90min to obtain a prepolymer. Add the prepolymer to the aqueous phase and adjust the stirring speed to 200r / min to obtain a sol with a particle size of about 500μm. React at 95℃ for 8 hours to obtain a ribbon-like rigid polymer. The reaction temperature of the suspension polymerization reaction exceeds the preferred range. The polymer undergoes a viscous flow transition at high temperature and severely adheres under stirring.

[0092] Example 7

[0093] A method for preparing a granular ion sieve, the specific preparation method includes the following steps:

[0094] Dissolve 5g of sodium chloride and 1g of polyvinyl alcohol in 100mL of water and stir in a 250mL three-necked flask. Heat to 85℃ to obtain an aqueous phase. Weigh out 10g of styrene, 2g of divinylbenzene, 0.12g of benzoyl peroxide, 10g of ethyl acetate, and 10g of liquid wax. Mix them thoroughly to obtain an oil phase. Add 6g of manganese-based ion sieve and heat in a water bath to 78℃ under electromagnetic stirring at 500r / min for 90min to obtain a prepolymer. Add the prepolymer to the aqueous phase and adjust the stirring speed to 200r / min to obtain a sol with a particle size of about 500μm. React at 85℃ for 6 hours. Wash the product with hot water until no foam is present, wash away excess water with ethanol, and air dry for 6 hours. Extract with petroleum ether for 6 hours to obtain granular ion sieve. Sieve through 450μm and 550μm mesh to obtain the final product.

[0095] Comparative Example 1

[0096] A method for preparing granular ion sieves differs from Example 1 in that slurrying and prepolymerization are carried out separately.

[0097] Dissolve 5g of sodium chloride and 1g of polyvinyl alcohol in 100mL of water and stir in a 250mL three-necked flask. Heat to 85℃ to obtain an aqueous phase. Weigh 10g of styrene, 2g of divinylbenzene, 0.12g of benzoyl peroxide, 10g of ethyl acetate, and 10g of liquid wax. Mix them evenly to obtain an oil phase. Add 6g of manganese-based ion sieve and slurry for 1 hour under electromagnetic stirring at 500r / min. Then heat in a water bath to 78℃ and react for 90min to obtain a prepolymer. Add the prepolymer to the aqueous phase and adjust the stirring speed to 200r / min to obtain a sol with a particle size of about 500μm. React at 85℃ for 6 hours. Wash the product with hot water until there is no foam, wash away excess water with ethanol, and air dry for 6 hours. Then extract with petroleum ether for 6 hours to obtain some granular ion sieves and white spheres. The loading is much lower than that of the product that is slurryed and prepolymerized simultaneously.

[0098] Comparative Example 2

[0099] A method for preparing granular ion sieves differs from Example 1 in that no prepolymerization is performed, and slurry polymerization and suspension polymerization are carried out simultaneously.

[0100] Dissolve 5g of sodium chloride and 1g of polyvinyl alcohol in 100mL of water and stir in a 250mL three-necked flask. Heat to 85℃ to obtain an aqueous phase. Weigh out 10g of styrene, 2g of divinylbenzene, 0.12g of benzoyl peroxide, 10g of ethyl acetate, and 10g of liquid wax. Mix them thoroughly to obtain an oil phase. Add 6g of manganese-based ion sieve to the aqueous phase and adjust the stirring speed to 200r / min to obtain a sol with a particle size of about 500μm. React at 85℃ for 6 hours. Wash the product with hot water until there is no foam, and wash away excess water with ethanol. The product is a completely unloaded white sphere, and the ion sieve powder is completely lost during washing.

[0101] The performance of the granular ion sieves provided in Examples 1-7 and Comparative Examples 1-2 was tested using the following methods:

[0102] (1) Particle size: The particle size was determined by using a laser particle size analyzer. A certain amount of granular ion sieve was added to water and stirred. The refractive index was measured to determine the particle size.

[0103] (2) Moisture content: The moisture content was determined using a moisture analyzer. Approximately 1g of granular ion sieve was placed in the moisture analyzer, and a rapid measurement was performed at 160℃ for 3 minutes.

[0104] (3) Pelletization rate: The product is weighed after sieving, and the moisture content is determined to determine its dry weight m. The total mass of polymer monomers and ion sieve powder during feeding is m0, and m0 / m is the pelletization rate.

[0105] (4) Saturated adsorption capacity: Lithium hydroxide solutions with concentrations of 0.5 g / L, 1 g / L, 1.5 g / L, and 2 g / L were selected as simulation solutions. A granular ion sieve with a dry weight of m was placed in an Erlenmeyer flask, and a volume of simulation solution of V was added. Static adsorption was carried out in a constant temperature shaker. The lithium concentrations of the adsorbed solution and the initial simulation solution were determined by ICP to be c and c0, respectively. The saturated adsorption capacity was (c-c0)*V / m.

[0106] (5) Adsorption equilibrium time: Prepare a certain amount of 500ppm lithium hydroxide solution, put it into a granular ion sieve, and perform static adsorption in a constant temperature shaker. Take a sample every half hour and use ICP to determine the lithium concentration until the lithium concentration no longer changes. The time taken is the adsorption equilibrium time.

[0107] Table 1

[0108]

[0109] As can be seen from the data in Table 1, compared with Comparative Examples 1-2, the granular ion sieves synthesized by the method provided by the present invention in Examples 1-4 and 7 are black, non-adhesive spherical, with controllable particle size (250-850 μm), water content greater than 50%, and spherical formation rate greater than 70% after sieving. Example 3 uses only divinylbenzene as the polymerization monomer to obtain an ion sieve with 100% crosslinking degree and high temperature and pressure resistance.

[0110] Table 2

[0111]

[0112] As can be seen from the data in Table 2, the saturated adsorption capacity of the granular ion sieves synthesized in Examples 1-4 and Example 7 is higher than that of Comparative Examples 1-2, and the adsorption equilibrium time is longer. The saturated adsorption capacity and saturated adsorption equilibrium time after 10 repetitions are also significantly improved compared with Comparative Examples 1-2.

[0113] The applicant declares that the present invention is illustrated by the above embodiments to demonstrate a granular ion sieve, its preparation method, and its application. However, the present invention is not limited to the above embodiments, that is, it does not mean that the present invention must rely on the above embodiments to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent substitutions of the raw materials of the product of the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for producing a granular ion-sieve, characterized by, The preparation method comprises the following steps: (1) dissolving polymer monomers in an organic solvent to obtain an oil phase, mixing the oil phase with ion sieve powder, and performing a prepolymerization reaction and slurry under stirring to obtain a prepolymer; (2) mixing the prepolymer obtained in step (1) with an aqueous phase containing a high molecular dispersant, and performing a suspension polymerization reaction to obtain the granular ion sieve; The reaction temperature of the prepolymerization reaction in step (1) is 65-80°C; The saturated adsorption capacity of the granular ion sieve is 10.3-16.3 mg / g.

2. The production method according to claim 1, characterized by, The polymer monomers in step (1) comprise a mono-olefin monomer and / or a crosslinking monomer.

3. The production method according to claim 2, characterized by, The polymer monomers comprise any one or a combination of at least two of styrene, a styrene modified monomer, a crosslinking monomer, or a methacrylate monomer.

4. The production method according to claim 3, characterized by, The styrene modified monomer comprises chloromethyl styrene.

5. The preparation method according to claim 3, characterized in that, The crosslinking monomer comprises divinyl benzene.

6. The preparation method according to claim 3, characterized in that, The methacrylate monomer comprises methyl methacrylate and / or ethylene glycol methacrylate.

7. The preparation method according to claim 2, characterized in that, The mass of the crosslinking monomer is 0-100% based on 100% of the polymer monomers.

8. The method of claim 1, wherein, The oil phase in step (1) further comprises an initiator and a pore-forming agent.

9. The production method according to claim 8, characterized by, The initiator is an oil-soluble initiator.

10. The method of claim 9, wherein, The initiator comprises dibenzoyl peroxide.

11. The preparation method according to claim 8, characterized in that, The amount of the initiator is 0.5-3% of the mass of the polymer monomers.

12. The method of claim 8, wherein, The pore-forming agent is an oil-soluble inert substance.

13. The method of claim 12, wherein, The pore-forming agent comprises liquid wax and / or white oil.

14. The preparation method according to claim 8, characterized in that, The amount of the pore-forming agent is 1-100% of the mass of the polymer monomers.

15. The method of claim 1, wherein, The organic solvent is an aliphatic short-chain lipid or a long-chain alcohol.

16. The method of claim 15, wherein, The organic solvent comprises any one or a combination of at least two of ethyl acetate, isooctanol, butyl acetate, or toluene.

17. The method of claim 1, wherein, The amount of the organic solvent is 1-100% of the mass of the polymer monomers.

18. The method of claim 1, wherein, The amount of the ion sieve powder in step (1) is 1-50% of the mass of the polymer monomers.

19. The method of claim 1, wherein, The ion sieve powder comprises a manganese-based ion sieve.

20. The method of claim 1, wherein, The particle size of the ion sieve powder is <1 μm.

21. The method of claim 1, wherein, The reaction time of the prepolymerization reaction in step (1) is 30-90 min.

22. The method of claim 1, wherein, The volume ratio of the oil phase to the aqueous phase is 1: (2-6).

23. The method of claim 1, wherein, The high molecular dispersant comprises polyvinyl alcohol.

24. The method of claim 1, wherein, The mass concentration of the high molecular dispersant in the aqueous phase in step (2) is 0.5-3%.

25. The method of claim 1, wherein, The aqueous phase in step (2) further comprises an inorganic salt.

26. The method of claim 25, wherein, The inorganic salt comprises sodium chloride.

27. The method of claim 25, wherein, The mass concentration of the inorganic salt in the aqueous phase in step (2) is 2-10%.

28. The method of claim 1, wherein, The reaction temperature of the suspension polymerization reaction in step (2) is 75-90°C.

29. The method of claim 1, wherein, The reaction time of the suspension polymerization reaction in step (2) is 5-10 h.

30. The method of claim 1, wherein, The preparation method specifically comprises the following steps: (1) mixing polymer monomers, an initiator, a pore-forming agent, and an organic solvent to obtain an oil phase, mixing the oil phase with ion sieve powder, and performing a prepolymerization reaction and slurry under stirring to obtain a prepolymer; The polymer monomers comprise a mono-olefin monomer and / or a crosslinking monomer, the initiator is an oil-soluble initiator, the pore-forming agent is an oil-soluble inert substance, the organic solvent is an aliphatic short-chain lipid or a long-chain alcohol, the particle size of the ion sieve powder is <1 μm, the reaction temperature of the prepolymerization reaction is 65-80°C, and the reaction time is 30-90 min; (2) mixing the prepolymer obtained in step (1) with an aqueous phase containing a high-molecular dispersant and an inorganic salt to perform a suspension polymerization reaction, thereby obtaining the granular ion sieve; the volume ratio of the oil phase to the aqueous phase is 1: (2-6); the mass concentration of the high-molecular dispersant in the aqueous phase is 0.5-3%; the mass concentration of the inorganic salt in the aqueous phase is 2-10%; the reaction temperature of the suspension polymerization reaction is 78-90°C, and the reaction time is 5-10 h.

31. A granular ion sieve characterized by, The granular ion sieve is prepared by the preparation method according to any one of claims 1-30.

32. The granular ion-sieve of claim 31, wherein, The particle size of the granular ion sieve is 300-1000 μm.

33. The granular ion-sieve of claim 31, wherein, The water content of the granular ion sieve is 50-65 wt%.

34. Use of the granular ion sieve according to any one of claims 31-33 in an adsorbent.

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