A type A zeolite adsorbent based on ionic rare earth tailings and its preparation method

Abstract

This invention belongs to the field of solid waste resource utilization and environmental protection technology, specifically relating to a type A zeolite adsorbent material based on ionic rare earth tailings and its preparation method. The invention involves sieving ionic rare earth tailings to obtain fine-grained particles rich in clay components, followed by heat treatment and alkaline solution crystallization to obtain type A zeolite. Then, thiol groups are grafted onto the zeolite surface using a silane coupling agent. Finally, an olefin compound containing terminal tert-butyl groups, phenolic hydroxyl groups, amino groups, Schiff bases, and a heptyl ring with a stereochemical structure is grafted onto the zeolite surface using a Michael addition reaction between thiol groups and double bonds. The phenolic hydroxyl, amino, and tert-butyl groups on the material surface form a good hydrophilic-hydrophobic structure, effectively improving the surface activity of the zeolite material, promoting the approach of heavy metal ions to the zeolite surface, and thus enhancing the adsorption effect of heavy metal ions.

Description

Technical Field

[0001] This invention belongs to the field of solid waste resource utilization and environmental protection technology, specifically relating to a type A zeolite adsorbent material based on ionic rare earth tailings and its preparation method. Background Technology

[0002] The framework of zeolite materials is a complex three-dimensional spatial structure formed by silicon-oxygen tetrahedra and aluminum-oxygen tetrahedra. Zeolite molecular sieves possess advantages such as large specific surface area, unique ion exchange capacity, and adsorption capacity, making them one of the most studied adsorption materials. Furthermore, they exhibit high temperature resistance, acid resistance, and radiation resistance, which determine their significant application prospects in water pollution control. This invention prepares high-performance zeolite materials for treating wastewater containing heavy metals, demonstrating high application value in the field of environmental protection.

[0003] Currently, the preparation methods for zeolite materials can be divided into three categories according to the different raw materials: the first method uses high-purity chemical reagents as the silicon-aluminum source for material preparation; the second method uses high-purity silicon-aluminum minerals as raw materials, which are pre-activated before being used for zeolite material preparation; and the third method uses silicon-aluminum-containing solid waste as raw material to prepare zeolite materials. The first method can obtain zeolite materials with relatively consistent physicochemical properties and has the highest controllability in the preparation process, but it requires a large amount of chemical reagents, resulting in high process costs and the potential generation of harmful substances during synthesis. The second method uses silicon-aluminum in minerals as the main raw material, avoiding the secondary pollution risks brought by chemical reagents, but it has certain requirements for mineral purity. The third method uses silicon-aluminum components in solid waste as raw materials, which significantly reduces the preparation process and cost and achieves the goal of "turning waste into treasure," but the complex chemical composition makes the controllability of the preparation process poor.

[0004] Chinese patent document CN117718008A discloses a binder-free type A zeolite microsphere adsorbent material for adsorbing strontium ions, its preparation method, and its application. The method involves synthesizing type A zeolite by heating silica / chitosan and sodium aluminum carbonate, followed by calcining the type A zeolite / chitosan hybrid microspheres to obtain binder-free type A zeolite microspheres. The type A zeolite microsphere adsorbent material synthesized by this method exhibits good adsorption performance for radioactive wastewater containing strontium. However, the alumina and silica used in the synthesis of type A zeolite by this method are derived from pure chemical reagents silica and sodium aluminum carbonate. In wastewater treatment processes, the large-scale preparation of the adsorbent is complex, and the raw material sourcing is uneconomical.

[0005] The preparation of adsorbent zeolites from solid waste rich in aluminum and silicon has become a research hotspot. Mining solid waste is a widely available and inexpensive raw material, and its use in preparing zeolite-based adsorbent materials for environmental remediation can truly realize the environmental governance concept of "using waste to treat waste and turning waste into treasure." Ionic rare earth tailings are mainly composed of minerals such as quartz, clay, mica, and feldspar, containing abundant silicon and aluminum components, and are a potential source of silicon and aluminum for the preparation of zeolite-based materials. However, the adsorption capacity and selectivity of type A zeolites prepared from ionic rare earth tailings currently exhibit biases in the adsorption of lead ions. Summary of the Invention

[0006] This invention provides a type A zeolite adsorbent material based on ionic rare earth tailings and its preparation method, which can solve the problems of lead ion adsorption capacity and adsorption selectivity deviation of type A zeolite prepared using ionic rare earth tailings as raw materials.

[0007] To achieve the above-mentioned technical effects, the present invention provides a method for preparing type A zeolite adsorbent material based on ionic rare earth tailings, comprising the following steps:

[0008] (1) The ion-type rare earth tailings are screened to obtain clay-rich components. Then, the clay-rich components are subjected to heat treatment and alkaline solution crystallization treatment in sequence to obtain zeolite materials.

[0009] (2) The zeolite material is reacted with a mercaptosilane coupling agent to obtain a mercapto-modified zeolite material; then, the mercapto-modified zeolite material and a functional olefin compound are subjected to a Michael addition reaction to obtain a type A zeolite adsorbent material; the structure of the functional olefin compound is as follows:

[0010] .

[0011] Preferably, the screening is carried out using a 200-mesh sieve, and the clay-rich component is ion-type rare earth tailings with a particle size greater than 200 mesh.

[0012] Preferably, the heat treatment temperature is 550~850℃ and the time is 1~3h; the alkaline solution used for the alkaline solution crystallization treatment is a sodium hydroxide solution with a concentration of 1~5mol / L, the alkaline solution crystallization treatment temperature is 45~85℃ and the time is 3~10h, and the mass ratio of the clay-rich component and the alkaline solution after heat treatment is 1:5~20.

[0013] Preferably, the method for reacting zeolite materials and mercaptosilane coupling agents is as follows: zeolite materials, water, ethanol and mercaptosilane coupling agents are mixed and reacted at 90~95°C for 16~20h.

[0014] Preferably, the mass ratio of the zeolite material, water, ethanol and mercaptosilane coupling agent is 5:8~15:90~100:7~10; the mercaptosilane coupling agent is γ-mercaptopropyltrimethoxysilane.

[0015] Preferably, the Michael addition reaction is carried out as follows: the mercapto-modified zeolite material, the functional olefin compound, the triethylamine and the solvent are mixed and reacted at 50-55°C for 24-30 h.

[0016] Preferably, the mass ratio of the mercapto-modified zeolite material, the functional olefin compound, and the triethylamine is 4:5~8:0.2~0.4.

[0017] Preferably, the average particle size of the zeolite material is 3~5μm.

[0018] Preferably, the preparation method of the functional olefin compound is as follows: 2,4-di-tert-butylphenol and N-hydroxymethylacrylamide in a molar ratio of 1:1 are subjected to a Friedel-Crafts alkylation reaction to obtain acrylamide-tert-butylphenol compounds; then, acrylamide-tert-butylphenol compounds in a molar ratio of 1:1 are subjected to a Michael addition reaction with diethylenetriamine to obtain amino-tert-butylphenol compounds; then, amino-tert-butylphenol compounds in a molar ratio of 1:1 are subjected to a Schiff base reaction with myrtol to obtain the functional olefin compound.

[0019] The present invention also provides a type A zeolite adsorbent material prepared by the method described above for preparing type A zeolite adsorbent material based on ionic rare earth tailings.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) This invention uses ionic rare earth tailings as raw material, which contains abundant aluminum and silicon components and can be used as the source of aluminum and silicon elements for preparing zeolite materials. This material is not only inexpensive and readily available, but also enables the resource utilization and high-value utilization of tailings, realizing "turning waste into treasure". The method of preparing zeolite materials using ionic rare earth tailings in this invention is simple to operate and has good controllability. Only heat treatment and crystallization processes are required to obtain zeolite materials.

[0022] (2) This invention obtains fine-grained particles rich in clay components by screening ionic rare earth tailings, followed by heat treatment and alkaline solution crystallization to obtain type A zeolite. Then, thiol groups are grafted onto the zeolite surface using a silane coupling agent. Finally, an olefin compound containing terminal tert-butyl groups, phenolic hydroxyl groups, amino groups, Schiff bases, and a heptyl ring with a stereostructure is grafted onto the zeolite surface using a Michael addition reaction between thiol groups and double bonds. The phenolic hydroxyl groups, amino groups, and tert-butyl groups on the material surface form a good hydrophilic-hydrophobic structure, effectively improving the surface activity of the zeolite material and promoting the approach of heavy metal ions to the zeolite surface, thereby improving the adsorption effect of heavy metal ions. Furthermore, the Schiff bases and phenolic hydroxyl groups on the zeolite surface can enhance the adsorption effect of heavy metal ions through conjugation and electrostatic attraction; the amide groups and amino groups on the zeolite surface can enhance the adsorption effect of heavy metal ions through electrostatic interaction and chelation; and the thioether bonds on the zeolite surface can enhance the adsorption effect of heavy metal ions through coordination complexation. Finally, the bicyclic [3.1.1]heptane ring with a three-dimensional structure and the two terminal tert-butyl groups on the surface of the zeolite material have large steric hindrance. They can cooperate with nearby thioether bonds, Schiff bases, amino groups, amide groups and phenolic hydroxyl groups through coordination, steric hindrance, chelation, electrostatic interaction and conjugation effect to form a comprehensive physicochemical system for adsorbing and binding lead ions, thereby improving the adsorption capacity and selective adsorption of lead ions. Attached Figure Description

[0023] Figure 1 The above is the 1H NMR spectrum of the functional olefin compound prepared in Example 1 of this invention;

[0024] Figure 2 The images show the XRD patterns of zeolite materials obtained by different alkaline solution crystallization times in Examples 1-3 of this invention. Detailed Implementation

[0025] The following examples are intended to further illustrate the content of the present invention, rather than to limit the scope of protection of the present invention.

[0026] The composition of the ionic rare earth tailings used in the following embodiments and comparative examples is shown in Table 1.

[0027] Table 1. Chemical composition ratio of ion-adsorption rare earth tailings (%)

[0028] <![CDATA[SiO2]]> <![CDATA[Al2O3]]> MgO CaO <![CDATA[K2O]]> <![CDATA[Na2O]]> <![CDATA[Fe2O3]]> <![CDATA[SO3]]> <![CDATA[Rb2O]]> <![CDATA[Y2O3]]> Loss on ignition 61.60 24.86 0.32 0.09 4.41 0.39 1.95 0.21 0.10 0.05 6.02

[0029] Example 1

[0030] The preparation method of type A zeolite adsorbent material based on ionic rare earth tailings in this embodiment includes the following steps:

[0031] (1) The ion-type rare earth tailings were screened using a 200-mesh standard sieve. The sieved material (rich in clay components) was heat-treated (at a temperature of 850℃ for 1 hour). The heat-treated sieved material was then added to a stirred tank with a 5 mol / L NaOH solution at a mass ratio of 1:10 for stirring and mixing reaction (alkaline solution crystallization treatment). The stirring and mixing reaction was carried out at a temperature of 85℃ for 3 hours. After the reaction was completed, the system was filtered, washed, dried and ground in sequence to obtain zeolite materials with an average particle size of 3 μm.

[0032] (2) 2,4-Di-tert-butylphenol, N-hydroxymethylacrylamide, aluminum chloride, and anhydrous tetrahydrofuran in a molar ratio of 1:1:2:6 were added to a reaction vessel, heated to 35°C, and stirred for 40 h. Then, water and ethyl acetate were added to the reaction vessel for extraction. The extracted organic phase was distilled under reduced pressure to obtain acrylamide-tert-butylphenol compounds. Then, acrylamide-tert-butylphenol compounds, diethylenetriamine, triethylamine, and anhydrous tetrahydrofuran in a molar ratio of 1:1:0.02:5 were added to the reaction vessel and heated. The mixture was stirred at 70°C for 6 hours, then distilled under reduced pressure to remove triethylamine and tetrahydrofuran, yielding amino-tert-butylphenol compounds. Finally, amino-tert-butylphenol compounds, myrtol, acetic acid, and ethanol in a molar ratio of 1:1:0.01:11 were added to the reaction vessel, heated to 35°C, and stirred for 8 hours. The mixture was then distilled under reduced pressure to obtain the crude product. The crude product was purified by column chromatography using ethyl acetate, dichloromethane, and methanol in a volume ratio of 7:2:1 to obtain functional olefin compounds. The 1H NMR spectrum of the functional olefin compounds is shown below. Figure 1 As shown, the chemical structure is as follows:

[0033] .

[0034] (3) Add zeolite material, deionized water, ethanol and γ-mercaptopropyltrimethoxysilane in a mass ratio of 5:8:90:7 to the reaction vessel, heat to 90°C, stir and reflux for 16 h, filter, wash the filter cake with ethanol, and dry to obtain mercapto-modified zeolite material.

[0035] (4) Add mercapto-modified zeolite material, functional olefin compound, triethylamine and anhydrous tetrahydrofuran in a mass ratio of 4:5:0.2:15 to a reaction vessel, heat to 50°C, stir and react for 24 hours, filter, wash the filter cake with tetrahydrofuran, water and ethanol in sequence, and dry to obtain type A zeolite adsorbent material based on ionic rare earth tailings.

[0036] Example 2

[0037] The preparation method of type A zeolite adsorbent material based on ionic rare earth tailings in this embodiment includes the following steps:

[0038] (1) The ion-type rare earth tailings were screened using a 200-mesh standard sieve. The sieved material (rich in clay components) was heat-treated (at a temperature of 850℃ for 1 hour). The heat-treated sieved material was then added to a stirred tank with a 5 mol / L NaOH solution at a mass ratio of 1:10 for stirring and mixing reaction (alkaline solution crystallization treatment). The stirring and mixing reaction was carried out at a temperature of 85℃ for 8 hours. After the reaction was completed, the system was filtered, washed, dried and ground in sequence to obtain zeolite materials with an average particle size of 4 μm.

[0039] (2) 2,4-Di-tert-butylphenol, N-hydroxymethylacrylamide, aluminum chloride, and anhydrous tetrahydrofuran in a molar ratio of 1:1:2:7 were added to a reaction vessel, heated to 40°C, and stirred for 47 h. Then, water and ethyl acetate were added to the reaction vessel for extraction. The extracted organic phase was distilled under reduced pressure to obtain acrylamide-tert-butylphenol compounds. Then, acrylamide-tert-butylphenol compounds, diethylenetriamine, triethylamine, and anhydrous tetrahydrofuran in a molar ratio of 1:1:0.03:6 were added to a reaction vessel and heated. The mixture was stirred at 75°C for 7 hours, then distilled under reduced pressure to remove triethylamine and tetrahydrofuran, yielding amino-tert-butylphenol compounds. Finally, amino-tert-butylphenol compounds, myrtol, acetic acid, and ethanol in a molar ratio of 1:1:0.02:13 were added to the reaction vessel, heated to 38°C, and stirred for 9 hours. The mixture was then distilled under reduced pressure to obtain a crude product. This crude product was purified by column chromatography using ethyl acetate, dichloromethane, and methanol in a volume ratio of 7:2:1 to obtain a functional olefin compound. The chemical structure of the functional olefin compound is as follows:

[0040] .

[0041] (3) Add zeolite material, deionized water, ethanol and γ-mercaptopropyltrimethoxysilane in a mass ratio of 5:11:95:9 to a reaction vessel, heat to 92°C, stir and reflux for 17 h, filter, wash the filter cake with ethanol, and dry to obtain mercapto-modified zeolite material.

[0042] (4) Add mercapto-modified zeolite material, functional olefin compound, triethylamine and anhydrous tetrahydrofuran in a mass ratio of 4:7:0.3:19 to a reaction vessel, heat to 52°C, stir and react for 26 h, filter, wash the filter cake with tetrahydrofuran, water and ethanol in sequence, and dry to obtain type A zeolite adsorbent material based on ionic rare earth tailings.

[0043] Example 3

[0044] The preparation method of type A zeolite adsorbent material based on ionic rare earth tailings in this embodiment includes the following steps:

[0045] (1) The ion-type rare earth tailings were screened using a 200-mesh standard sieve. The undersize material (rich in clay components) obtained by sieving was heat-treated (the temperature of heat treatment was 850℃ and the time was 1h). Then, the heat-treated undersize material and a 5mol / L NaOH solution were added to a stirred tank at a mass ratio of 1:10 for stirring and mixing reaction (alkaline solution crystallization treatment). The temperature of stirring and mixing reaction was 85℃ and the time was 10h. After the reaction was completed, the system was filtered, washed, dried and ground in sequence to obtain zeolite material with an average particle size of 5μm.

[0046] (2) 2,4-Di-tert-butylphenol, N-hydroxymethylacrylamide, aluminum chloride, and anhydrous tetrahydrofuran in a molar ratio of 1:1:3:8 were added to a reaction vessel, heated to 45°C, and stirred for 50 h. Water and ethyl acetate were then added to the reaction vessel for extraction. The extracted organic phase was distilled under reduced pressure to obtain acrylamide-tert-butylphenol compounds. Then, acrylamide-tert-butylphenol compounds, diethylenetriamine, triethylamine, and anhydrous tetrahydrofuran in a molar ratio of 1:1:0.03:7 were added to the reaction vessel and heated to... The mixture was stirred at 80℃ for 9 hours, then distilled under reduced pressure to remove triethylamine and tetrahydrofuran, yielding amino-tert-butylphenol compounds. Finally, amino-tert-butylphenol compounds, myrtol, acetic acid, and ethanol in a molar ratio of 1:1:0.03:14 were added to the reaction vessel, heated to 40℃, stirred for 10 hours, and distilled under reduced pressure to obtain the crude product. The crude product was purified by column chromatography using ethyl acetate, dichloromethane, and methanol in a volume ratio of 7:2:1 to obtain functional olefin compounds. The chemical structures of the functional olefin compounds are as follows:

[0047] .

[0048] (3) Add zeolite material, deionized water, ethanol and γ-mercaptopropyltrimethoxysilane in a mass ratio of 5:15:100:10 to a reaction vessel, heat to 95°C, stir and reflux for 20 h, filter, wash the filter cake with ethanol, and dry to obtain mercapto-modified zeolite material.

[0049] (4) Add mercapto-modified zeolite material, functional olefin compound, triethylamine and anhydrous tetrahydrofuran in a mass ratio of 4:8:0.4:20 to a reaction vessel, heat to 55°C, stir and react for 30 h, filter, wash the filter cake with tetrahydrofuran, water and ethanol in sequence, and dry to obtain type A zeolite adsorbent material based on ionic rare earth tailings.

[0050] Comparative Example 1

[0051] The difference between the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example and the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in Example 1 is that 2,4-di-tert-butylphenol is replaced with 2-tert-butyl-p-cresol in step (2) of the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example.

[0052] Comparative Example 2

[0053] The difference between the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example and the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in Example 1 is that diethylenetriamine is replaced with ethylenediamine in step (2) of the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example.

[0054] Comparative Example 3

[0055] The difference between the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example and the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in Example 1 is that in step (2) of the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example, diethylenetriamine is replaced with triethylenetetramine.

[0056] Comparative Example 4

[0057] The difference between the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example and the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in Example 1 is that in step (2) of the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example, myrtol is replaced with crotonol.

[0058] Comparative Example 5

[0059] The difference between the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example and the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in Example 1 is that in step (2) of the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example, myrtol is replaced with 2,2-dimethyl-4-pentenol.

[0060] Comparative Example 6

[0061] The difference between the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example and the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in Example 1 is that in step (2) of the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example, myrtol is replaced with 3-cyclohexene-1-carboxaldehyde.

[0062] Comparative Example 7

[0063] The difference between the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example and the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in Example 1 is that in step (2) of the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example, myrtol is replaced with cinnamaldehyde.

[0064] Comparative Example 8

[0065] The difference between the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example and the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in Example 1 is that the functional olefin compound is replaced with acrylamide in step (4) of the preparation method of the type A zeolite adsorbent material based on ionic rare earth tailings in this comparative example.

[0066] Experimental Example 1

[0067] This experiment tested the XRD patterns of the zeolite materials prepared in Examples 1-3, and the results are as follows: Figure 2 As shown. By Figure 2 It can be seen that the XRD patterns of the zeolite materials prepared in Examples 1-3 all showed characteristic diffraction peaks of type A zeolite at approximately 7°, 10°, 16°, 21°, 24°, 27°, 30°, and 34° of 2θ, indicating that the reaction products of the heat-treated ionic rare earth tailings after different reaction times were mainly type A zeolite phase.

[0068] Experiment Example 2

[0069] This experimental example was used to test the adsorption rate of type A zeolite adsorbent materials prepared in each embodiment and comparative example for lead ions in solution. The test method is as follows: 0.1 g of type A zeolite adsorbent material was added to five groups of lead ion solutions with different initial pH values ​​(2, 3, 4, 5, 5.5), respectively. 2+ The concentration of each sample was 200 mg / L, and the volume was 150 mL. The sample was then placed in a constant temperature water bath shaker at 25°C and shaken for 60 minutes. After shaking, the sample was removed and centrifuged for solid-liquid separation. ICP was used to analyze the Pb content in the supernatant obtained from the centrifugation. 2+ The concentration of Pb was detected, and then the effect of type A zeolite adsorbent on Pb was calculated. 2+ The adsorption rate is calculated using the following formula:

[0070]

[0071] in, The adsorption rate is % (%), and C0 is the concentration of Pb in the lead ion solution. 2+ The initial concentration (mg / L), Ct To determine the Pb concentration in the lead ion solution after the adsorption test. 2+ The concentration (mg / L).

[0072] The adsorption rates of type A zeolite adsorbents prepared in each embodiment and comparative example for lead ions in solutions with different pH values ​​are shown in Table 2.

[0073] Table 2. Type A zeolites prepared in each example and comparative example

[0074] The adsorption rate of the adsorbent material for lead ions in solutions with different pH values

[0075]

[0076] Table 2 shows that the adsorption rate of lead ions by the type A zeolite adsorbent material prepared in this invention is higher than 96.5% when the pH range is 2-5.5. Furthermore, the adsorption rate increases slightly with increasing pH. In contrast, the adsorption rate of lead ions by the type A zeolite adsorbent materials prepared in Comparative Examples 1-8 is less than 20.5%. These conclusions indicate that the type A zeolite adsorbent material prepared in this invention has excellent lead ion adsorption performance. Moreover, it exhibits excellent lead ion adsorption performance over a wide pH range, demonstrating high application potential.

[0077] Experimental Example 3

[0078] This experimental example was used to test the adsorption rate of type A zeolite adsorbent materials prepared in each embodiment and comparative example for lead ions in solution. The test method is as follows: 0.1 g of type A zeolite adsorbent material was added to a lead ion solution with an initial pH of 4. 2+ The concentration was 200 mg / L, the volume was 150 mL, and then it was placed on a constant temperature water bath shaker at 25℃. After shaking for 1 min, 5 min, or 60 min, it was removed and solid-liquid separation was performed using a centrifuge. The Pb content in the supernatant obtained by centrifugation was analyzed by ICP. 2+ The concentration of Pb was detected, and then the effect of type A zeolite adsorbent on Pb was calculated. 2+ The adsorption rate is calculated using the following formula:

[0079]

[0080] in, The adsorption rate is % (%), and C0 is the concentration of Pb in the lead ion solution. 2+ The initial concentration (mg / L), C t To determine the Pb concentration in the lead ion solution after the adsorption test. 2+ The concentration (mg / L).

[0081] The adsorption rates of lead ions in solution by the type A zeolite adsorbent materials prepared in each embodiment and comparative example at different adsorption times are shown in Table 3.

[0082] Table 3. Type A zeolite adsorbents prepared in each example and comparative example

[0083] The adsorption rate of lead ions in solution by the material at different adsorption times

[0084]

[0085] As shown in Table 3, when the adsorption time is 1 min, the adsorption rate of lead ions by the type A zeolite adsorbent material prepared in this invention is higher than 97.1%. With the extension of adsorption time, the adsorption rate of lead ions by the type A zeolite adsorbent material gradually increases. From the test results of Examples 1-3 and Comparative Examples 1-8, it can be seen that when the adsorption time is 1 min, the adsorption rate of lead ions by the type A zeolite adsorbent material prepared in Examples 1-3 is already very close to the adsorption rate when the adsorption time is 60 min (the lowest adsorption rate at 1 min is 98.3% of the adsorption rate at 60 min), while the adsorption rate of lead ions by the type A zeolite adsorbent materials prepared in Comparative Examples 1-8 is less than 77% of the adsorption rate at 60 min when the adsorption time is 1 min. This conclusion indicates that the type A zeolite adsorbent material prepared in this invention has a relatively fast adsorption rate for lead ions.

[0086] Experiment Example 4

[0087] This experimental example is used to test the adsorption characteristics of the type A zeolite adsorbent materials prepared in each embodiment and comparative example for various heavy metal ions in solution. The experimental method is as follows: 0.1 g of type A zeolite adsorbent material (or the zeolite material prepared in step 1 of Example 1) was added to a heavy metal ion solution. The concentrations of lead, copper, zinc, magnesium, and nickel ions in the heavy metal ion solution were all 300 mg / L. The solution was then placed on a constant temperature water bath shaker at 25°C. After shaking for a certain period of time, the solution was removed and centrifuged for solid-liquid separation. The concentrations of lead, copper, zinc, magnesium, and nickel ions in the supernatant obtained from centrifugation were detected by ICP. The adsorption rate of the type A zeolite adsorbent material (or the zeolite material prepared in step 1 of Example 1) for each heavy metal ion was then calculated using the following formula:

[0088]

[0089] in, C is the adsorption rate (%), C0 is the initial concentration (mg / L) of a certain heavy metal ion in the heavy metal ion solution, and C t The concentration (mg / L) of a certain heavy metal ion in the heavy metal ion solution after the adsorption test.

[0090] The adsorption rates of lead, copper, zinc, magnesium and nickel ions in heavy metal ion solutions prepared by the A-type zeolite adsorbent materials in each embodiment and comparative example are shown in Table 4.

[0091] Table 4. Heavy metal adsorbents of type A zeolite adsorbents prepared in each example and comparative example.

[0092] Adsorption rates of lead, copper, zinc, magnesium, and nickel ions in ionic solutions

[0093]

[0094] Table 4 shows that the type A zeolite adsorbent material prepared in this invention has adsorption effects on lead, copper, zinc, magnesium, and nickel ions. However, the adsorption rate for lead ions is higher than 84.9%, while the adsorption rates for copper, zinc, magnesium, and nickel ions are all lower than 7.3%. The type A zeolite adsorbent materials prepared in Comparative Examples 1-8 all show low adsorption rates for lead, copper, zinc, magnesium, and nickel ions. The type A zeolite adsorbent materials prepared in Examples 1-3 show an adsorption rate for lead ions that is 11.5 times higher than that for copper, zinc, magnesium, and nickel ions, while the type A zeolite adsorbent materials prepared in Comparative Examples 1-8 show an adsorption rate for lead ions that is less than 2.8 times higher than that for copper, zinc, magnesium, and nickel ions. This conclusion indicates that the type A zeolite adsorbent material prepared in this invention has good adsorption selectivity for lead ions and can effectively adsorb and separate lead ions from heavy metal ion wastewater, showing promising application prospects.

[0095] In summary, this invention obtains fine-grained particles rich in clay components by screening ionic rare earth tailings, followed by heat treatment and alkaline solution crystallization to obtain type A zeolite. Then, thiol groups are grafted onto the zeolite surface using a silane coupling agent. Finally, an olefin compound containing terminal tert-butyl groups, phenolic hydroxyl groups, amino groups, Schiff bases, and a heptyl ring with a stereostructure is grafted onto the zeolite surface using a Michael addition reaction between the thiol groups and double bonds. The phenolic hydroxyl, amino, and tert-butyl groups on the material surface form a good hydrophilic-hydrophobic amphiphilic structure, effectively improving the surface activity of the zeolite material and promoting the approach of heavy metal ions to the zeolite surface, thereby enhancing the adsorption effect of heavy metal ions. Furthermore, the Schiff base and phenolic hydroxyl groups on the zeolite surface can enhance the adsorption effect of heavy metal ions through conjugation effects and electrostatic attraction; the amide and amino groups on the zeolite surface can enhance the adsorption effect of heavy metal ions through electrostatic interactions and chelation; and the thioether bonds on the zeolite surface can enhance the adsorption effect of heavy metal ions through coordination complexation. Finally, the bicyclic [3.1.1]heptane ring with a three-dimensional structure and the two terminal tert-butyl groups on the surface of the zeolite material have large steric hindrance. They can cooperate with nearby thioether bonds, Schiff bases, amino groups, amide groups and phenolic hydroxyl groups through coordination, steric hindrance, chelation, electrostatic interaction and conjugation effect to form a physicochemical comprehensive system for adsorbing and binding lead ions with large ionic radii, thereby improving the adsorption capacity and selective adsorption of lead ions.

Claims

1. A method for preparing type A zeolite adsorbent material based on ionic rare earth tailings, characterized in that, Includes the following steps: (1) The ion-type rare earth tailings are screened to obtain clay-rich components. Then, the clay-rich components are subjected to heat treatment and alkaline solution crystallization treatment in sequence to obtain zeolite materials. (2) The zeolite material is reacted with a mercaptosilane coupling agent to obtain a mercapto-modified zeolite material; then, the mercapto-modified zeolite material and a functional olefin compound are subjected to a Michael addition reaction to obtain a type A zeolite adsorbent material; the structure of the functional olefin compound is as follows: 。 2. The preparation method of type A zeolite adsorbent material based on ionic rare earth tailings as described in claim 1, characterized in that, The screening was carried out using a 200-mesh sieve, and the clay-rich components were ion-type rare earth tailings with a particle size greater than 200 mesh.

3. The preparation method of type A zeolite adsorbent material based on ionic rare earth tailings as described in claim 1, characterized in that, The heat treatment temperature is 550~850℃ and the time is 1~3h; the alkaline solution crystallization treatment uses a sodium hydroxide solution with a concentration of 1~5mol / L, the alkaline solution crystallization treatment temperature is 45~85℃ and the time is 3~10h, and the mass ratio of the clay-rich component and the alkaline solution after heat treatment is 1:5~20.

4. The preparation method of type A zeolite adsorbent material based on ionic rare earth tailings as described in claim 1, characterized in that, The reaction method of zeolite materials and mercaptosilane coupling agents is as follows: zeolite materials, water, ethanol and mercaptosilane coupling agents are mixed and reacted at 90~95℃ for 16~20h.

5. The preparation method of type A zeolite adsorbent material based on ionic rare earth tailings as described in claim 4, characterized in that, The mass ratio of the zeolite material, water, ethanol and mercaptosilane coupling agent is 5:8~15:90~100:7~10; the mercaptosilane coupling agent is γ-mercaptopropyltrimethoxysilane.

6. The preparation method of type A zeolite adsorbent material based on ionic rare earth tailings as described in claim 1, characterized in that, The Michael addition reaction is carried out as follows: mercapto-modified zeolite material, functional olefin compound, triethylamine and solvent are mixed and reacted at 50~55℃ for 24~30h.

7. The preparation method of type A zeolite adsorbent material based on ionic rare earth tailings as described in claim 6, characterized in that, The mass ratio of the mercapto-modified zeolite material, the functional olefin compound, and the triethylamine is 4:5~8:0.2~0.

4.

8. The preparation method of type A zeolite adsorbent material based on ionic rare earth tailings as described in claim 1, characterized in that, The average particle size of the zeolite material is 3~5μm.

9. The preparation method of type A zeolite adsorbent material based on ionic rare earth tailings as described in claim 1, characterized in that, The preparation method of the functional olefin compound is as follows: 2,4-di-tert-butylphenol and N-hydroxymethylacrylamide in a molar ratio of 1:1 are subjected to a Friedel-Crafts alkylation reaction to obtain acrylamide-tert-butylphenol compounds; then, acrylamide-tert-butylphenol compounds in a molar ratio of 1:1 are subjected to a Michael addition reaction with diethylenetriamine to obtain amino-tert-butylphenol compounds; then, amino-tert-butylphenol compounds in a molar ratio of 1:1 are subjected to a Schiff base reaction with myrtol to obtain the functional olefin compound.

10. A type A zeolite adsorbent prepared by the method for preparing type A zeolite adsorbent based on ionic rare earth tailings as described in any one of claims 1-9.

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