A crown ether-inorganic ion modified adsorbing material, a preparation method and application thereof

Abstract

The present application relates to a kind of crown ether-inorganic ion modified adsorption material and its preparation method and application, belong to heavy metal wastewater treatment technical field.The preparation method includes: the ion exchange of mixing metal cation salt solution and adsorption matrix material is carried out after drying treatment, and ion exchange modified sample is obtained;The ion exchange modified sample is immersed in the organic solvent containing crown ether, and crown ether-inorganic ion modified adsorption material is obtained.The preparation method provided by the present application has the advantages of mild reaction condition, simple process, low equipment investment and operating cost etc..At the same time, the crown ether-inorganic ion modified adsorption material provided by the present application can efficiently, quickly and selectively adsorb thallium ions in wastewater, to achieve the purpose of purifying water quality.

Description

Technical Field

[0001] The invention relates to a crown ether-inorganic ion modified adsorption material and a preparation method and application thereof, belonging to the technical field of heavy metal wastewater treatment. Background Art

[0002] Thallium is a widely distributed, rare, and highly toxic heavy metal, second only to methylmercury in toxicity. Thallium exhibits both lithophilic and sulfophilic properties. Its lithophilic nature manifests itself in its frequent presence as a trace element in silicate minerals such as albite, potassium feldspar, and mica, while its sulfophilic nature manifests itself in its frequent association with sulfide minerals such as lead, zinc, copper, and iron. The primary cause of thallium pollution is not the use of thallium and its compounds, but rather the release of thallium into the environment as an impurity in raw materials during certain industrial activities. These pollution incidents primarily result from the mining and smelting of sulfur-containing ores (such as pyrite, galena, sphalerite, smithsonite, and arsenite) and lithium ores. Due to its high toxicity, current standards require total thallium concentrations in industrial wastewater to be below 5 μg / L.

[0003] Currently, commonly used methods for thallium removal include ion exchange, redox precipitation, solvent extraction, and adsorption. Ion exchange offers high separation efficiency, is non-toxic, and is recyclable, but requires stringent operating conditions, is time-consuming, and ion exchange resins are expensive, with complex elution and regeneration procedures. Redox precipitation is relatively simple and inexpensive, but it also has several drawbacks. For example, it requires a large amount of sulfiding agent, which produces an insoluble sulfide precipitate. Furthermore, because sulfide is toxic, if the dosage is not strictly controlled, H₂S gas can be generated, further polluting the environment and causing operator poisoning. Solvent extraction offers fast reaction times and high efficiency, but it also imposes stringent system requirements, and the extractant and diluent are somewhat toxic, leading to secondary pollution. Adsorption is considered one of the best water treatment technologies due to its convenience, ease of operation, wide adaptability, and high efficiency. Materials with good adsorption properties for thallium include metal oxides such as Fe, Mn, and Ti, Prussian blue and its analogs, and biochar.

[0004] Because thallium concentrations in industrial thallium-containing wastewater are typically low and often contain multiple heavy metal contamination, highly selective thallium removal agents are required. Furthermore, given the large volume of industrial thallium-containing wastewater, thallium removal treatment must be cost-effective to maximize economic benefits. However, current thallium wastewater treatment methods and principles are often limited, making it difficult to achieve deep removal of trace amounts of thallium. The treatment of industrial thallium-containing wastewater still faces several challenges.

[0005] Therefore, it is necessary to develop economical, efficient and highly selective thallium pollution remediation materials to provide solutions and technical support for the treatment of thallium-containing wastewater. Summary of the Invention

[0006] In view of the problems of poor selectivity, low efficiency, high cost and complex preparation process of existing thallium removal agents, one of the objectives of the present invention is to provide a preparation method of crown ether-inorganic ion modified adsorption material, which has the advantages of mild reaction conditions, simple process, low equipment investment and operating costs.

[0007] A second object of the present invention is to provide a crown ether-inorganic ion modified adsorption material, which improves the adsorption capacity of thallium through cation exchange. At the same time, the selective adsorption capacity of thallium is achieved through the selective complexation between the crown ether and the thallium ion. The material is used for the adsorption of thallium ions in water, has the characteristics of good selectivity and fast rate, and has good industrial application prospects.

[0008] The third object of the present invention is to provide a crown ether-inorganic ion modified adsorption material for use as a thallium adsorption material. The modified adsorption material can efficiently, quickly and selectively adsorb thallium ions in wastewater to achieve the purpose of purifying water quality.

[0009] In order to achieve the above object, the first aspect of the present invention is to provide a method for preparing a crown ether-inorganic ion modified adsorption material, the method comprising:

[0010] (1) mixing a metal cation salt solution with an adsorption matrix material, performing ion exchange, and then drying to obtain an ion exchange modified sample; the adsorption matrix material is selected from at least one of activated carbon, biochar, molecular sieve, and carbon aerogel;

[0011] (2) Immersing the ion exchange modified sample in an organic solvent containing a crown ether to obtain a crown ether-inorganic ion modified adsorption material.

[0012] The innovation of the present invention lies in fully stirring and mixing a specific adsorption matrix material with a cationic salt solution to cause ion exchange, drying to obtain an ion exchange modified sample, and then continuing to immerse the ion exchange modified sample in an organic solvent containing a crown ether to obtain a crown ether-inorganic ion modified adsorption material. The adsorption matrix material provided by the present invention has a stable structure, a rich pore structure and a large specific surface area, and can provide adsorption sites and exchangeable cations. At the same time, the adsorption capacity of the crown ether-inorganic ion modified adsorption material and thallium is improved by cation exchange. Further, by immersing it in an organic solvent containing a crown ether, the selective complexation of thallium ions is improved, and the selective adsorption capacity for thallium is achieved. The method provided by the present invention integrates inorganic modification and organic modification, comprehensively improves the performance of the adsorption matrix material, does not generate harmful waste, and has mild reaction conditions.

[0013] As a preferred solution, the metal cation salt is selected from at least one of lithium salt, potassium salt and sodium salt. + , K + and Na+ All are monovalent alkali metal cations, and Tl + Has similar properties and is more easily compared to Tl + Ion exchange occurs.

[0014] As a preferred solution, the concentration of the metal cation salt solution is 0.1-3 mol / L.

[0015] As a preferred embodiment, the metal cation salt is selected from at least one of lithium sulfate, lithium nitrate, lithium chloride, potassium sulfate, potassium nitrate, potassium chloride, sodium sulfate, sodium nitrate, and sodium chloride.

[0016] As a preferred solution, the liquid-to-solid ratio of the metal cation salt solution to the adsorption matrix material is 20-100 ml / g.

[0017] As a preferred solution, the ion exchange conditions are: stirring speed of 100-500 rpm, reaction temperature of 25-95°C, reaction time of 1-8 h, and exchange times of at least 2 times. Under the preferred temperature and stirring rate conditions, the ion exchange rate can be accelerated. If the temperature is too high, it will affect the structure of the matrix material. Too few ion exchanges will result in too little exchange of metal cations, reducing Tl + removal rate.

[0018] As a more preferred solution, the number of exchanges is 1 to 5 times.

[0019] As a preferred solution, the drying treatment conditions are: temperature of 80-150° C. and time of 8-20 hours.

[0020] As a preferred solution, the method further comprises first centrifuging the product obtained after the ion exchange and then performing the drying treatment.

[0021] As a preferred embodiment, the crown ether is selected from at least one of 18-crown-6, aza-18-crown-6, thia-18-crown-6 and dibenzo-18-crown-6.

[0022] As a preferred solution, the concentration of the crown ether in the organic solution is 10-100 g / L.

[0023] As a preferred embodiment, the organic solvent is selected from at least one of N,N-dimethylformamide, dichloromethane, tetrahydrofuran, benzene, and toluene. Under these preferred conditions, the crown ether has a high solubility in the organic solvent, resulting in a more concentrated crown ether solution, thereby increasing the loading rate of the crown ether on the material.

[0024] As a preferred solution, the liquid-to-solid ratio of the crown ether-containing organic solvent to the ion exchange modified sample is 20-100 ml / g.

[0025] As a preferred embodiment, the impregnation conditions are: reaction time of 1 to 24 hours and reaction temperature of 25 to 80°C. Impregnation under these preferred conditions can accelerate the loading of the crown ether onto the material. However, excessively high temperatures can cause the organic solvent and crown ether to volatilize, reducing the amount of crown ether loaded.

[0026] As a preferred solution, the immersion is carried out under stirring conditions.

[0027] It should be noted that the present invention has no special requirements for the stirring conditions of the immersion, and any conditions known in the art may be used.

[0028] As a preferred solution, the ion exchange modified sample is immersed in an organic solvent containing crown ether, and the sample obtained after the immersion is subjected to solid-liquid separation, washed and dried to obtain the crown ether-inorganic ion modified adsorption material.

[0029] As a preferred solution, it should be noted that the present invention has no special requirements for the conditions of solid-liquid separation, washing and drying, and any conditions known in the art may be used.

[0030] The present invention also provides a crown ether-inorganic ion modified adsorption material prepared by the above-mentioned preparation method. The modified adsorption material can efficiently, quickly and selectively adsorb thallium ions in wastewater.

[0031] The present invention also provides the use of a crown ether-inorganic ion modified adsorption material as a thallium adsorption material. The modified adsorption material can efficiently, quickly and selectively adsorb thallium ions in wastewater to achieve the purpose of purifying water quality.

[0032] As a preferred solution, the concentration of the crown ether-inorganic ion modified adsorption material in thallium-containing wastewater is not higher than 2 g / L, more preferably 0.05-1.5 g / L, and further preferably 0.5-1 g / L.

[0033] Compared with the prior art, the present invention has at least the following advantages:

[0034] (1) The preparation process of the crown ether-inorganic ion modified adsorption material provided by the present invention is simple, integrating inorganic modification and organic modification, comprehensively improving the performance of the adsorption matrix material, generating no harmful waste, and using mild reaction conditions.

[0035] (2) The crown ether-inorganic ion modified adsorption material provided by the present invention has selectivity and a high adsorption capacity for thallium ions, and can selectively adsorb thallium pollution characteristics in wastewater. Even under the condition that other metal ions exist in large quantities, the modified adsorption material still has excellent selective adsorption performance for thallium ions.

[0036] (3) The crown ether-inorganic ion modified adsorption material provided by the present invention is simple to use, requires a small amount of adsorption material to be added to thallium-contaminated wastewater, and has the potential for recycling and reuse. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 The XRD spectra of the 4A molecular sieve before and after potassium ion exchange modification in Example 1 are shown;

[0038] Figure 2 This is the Fourier transform infrared spectrum image of the 4A molecular sieve before modification in Example 1;

[0039] Figure 3 This is the Fourier transform infrared spectrum image of the crown ether-potassium ion modified 4A molecular sieve in Example 1;

[0040] Figure 4 This is the SEM-EDS image of the clinoptilolite before modification in Example 2;

[0041] Figure 5 This is the SEM-EDS image of the crown ether-potassium ion modified clinoptilolite in Example 2. DETAILED DESCRIPTION

[0042] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0043] The present invention is further described below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the following specific embodiments. Obviously, the embodiments described below are only a part of the embodiments, and all other embodiments obtained by professionals in this field without making creative efforts are still within the scope of protection of the present invention.

[0044] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0045] Example 1

[0046] (1) Add 1.0 g of 4A molecular sieve to 50 mL of 1 mol / L potassium chloride solution, heat and stir at 80°C for 1 h, and repeat the exchange twice, using fresh solution each time. Remove the supernatant by centrifugation, wash three times with deionized water, and dry in an oven at 105°C for 12 h. The resulting solid is the potassium ion exchange-modified 4A molecular sieve.

[0047] (2) Weigh 1.0 g of 18-crown-6 and add it to 50 ml of N,N-dimethylformamide. Then add 1.0 g of potassium ion exchange-modified molecular sieve and stir at room temperature for 12 h. Filter, wash with deionized water, and dry to obtain crown ether-potassium ion-modified 4A molecular sieve.

[0048] The present invention provides an exemplary XRD spectrum of the 4A type molecular sieve before and after potassium ion exchange modification in this embodiment, see Figure 1 ,It can be seen from the figure that after potassium ion exchange modification, the sample still maintains the complete structural characteristics of 4A type molecular sieve.

[0049] The present invention provides illustratively the Fourier transform infrared spectrum image of the 4A type molecular sieve before modification and the Fourier transform infrared spectrum image of the 4A type molecular sieve modified with crown ether-potassium ion in this embodiment, specifically see Figure 2 and Figure 3 ,from Figure 2 and Figure 3 It can be seen that the material is at 3446 cm -1 、1010 cm -1 、667 cm -1 The peak intensity at α-HPO changed and the peak position shifted significantly, confirming the successful loading of crown ether.

[0050] Example 2

[0051] (1) Add 1.0 g of clinoptilolite to 50 mL of 1 mol / L potassium chloride solution and heat with stirring at 80°C for 1 h. Repeat the exchange twice, using fresh solution each time. Remove the supernatant by centrifugation, wash three times with deionized water, and dry in an oven at 105°C for 12 h. The resulting solid is the potassium ion exchange-modified clinoptilolite.

[0052] (2) Weigh 1.0 g of 18-crown-6 and add it to 50 ml of N,N-dimethylformamide. Stir until the solid is completely dissolved. Then add 1.0 g of ion-exchange modified zeolite and stir at room temperature for 12 h. Filter, wash with deionized water, and dry to obtain crown-ether-potassium ion-modified clinoptilolite.

[0053] The present invention exemplarily provides the SEM-EDS image of the clinoptilolite before modification and the SEM-EDS image of the clinoptilolite modified with crown ether-potassium ions in this embodiment, as shown in FIG. Figure 4 Hehe Figure 5 ,contrast Figure 4 and Figure 5 It can be seen that the potassium ion content of the modified sample increases significantly, and the modification does not affect the morphology of the sample.

[0054] Example 3

[0055] (1) Add 1.0 g of 4A molecular sieve to 50 mL of 1 mol / L sodium chloride solution, heat and stir at 80°C for 1 h, and repeat the exchange twice, using fresh solution each time. Remove the supernatant by centrifugation, wash three times with deionized water, and dry in an oven at 105°C for 12 h. The resulting solid is the sodium ion exchange-modified 4A molecular sieve.

[0056] (2) Weigh 1.0 g of 18-crown-6 and add it to 50 ml of N,N-dimethylformamide. Then add 1.0 g of sodium ion exchange-modified molecular sieve and stir at room temperature for 12 h. Filter, wash with deionized water, and dry to obtain crown ether-sodium ion-modified 4A molecular sieve.

[0057] Example 4

[0058] (1) Add 1.0 g of activated carbon to 50 mL of 1 mol / L sodium chloride solution, heat and stir at 80°C for 1 h, and repeat the exchange twice, using fresh solution each time. Remove the supernatant by centrifugation, wash three times with deionized water, and dry in an oven at 105°C for 12 h. The resulting solid is the sodium ion exchange-modified activated carbon.

[0059] (2) Weigh 1.0 g of 18-crown-6 and add it to 50 ml of N,N-dimethylformamide. Then add 1.0 g of sodium ion exchange-modified activated carbon and stir at room temperature for 12 h. Filter, wash with deionized water, and dry to obtain crown ether-sodium ion-modified activated carbon.

[0060] Example 5

[0061] (1) Add 1.0 g of 4A molecular sieve to 30 mL of 1 mol / L potassium chloride solution, heat and stir at 50°C for 4 h, and repeat the exchange twice, using fresh solution each time. Remove the supernatant by centrifugation, wash three times with deionized water, and dry in an oven at 105°C for 12 h. The resulting solid is the potassium ion exchange-modified 4A molecular sieve.

[0062] (2) Weigh 1.0 g of aza-18-crown-6 and add it to 25 ml of N,N-dimethylformamide. Then add 1.0 g of potassium ion exchange-modified molecular sieve and stir at 50°C for 8 h. Filter, wash with deionized water, and dry to obtain crown ether-potassium ion-modified 4A molecular sieve.

[0063] Comparative Example 1

[0064] Weigh 1.0 g of 18-crown-6 and add it to 50 ml of N,N-dimethylformamide. Stir until the solid is completely dissolved. Then add 1.0 g of 4A molecular sieves and stir at room temperature for 12 hours. Filter, wash with deionized water, and dry to obtain crown-4A molecular sieves.

[0065] Comparative Example 2

[0066] Add 1.0 g of 4A molecular sieve to 50 mL of 1 mol / L potassium chloride solution and heat with stirring at 80°C for 1 hour. Repeat the exchange twice, using fresh solution each time. Remove the supernatant by centrifugation, wash three times with deionized water, and dry in an oven at 105°C for 12 hours. The resulting solid is the potassium ion-exchange-modified 4A molecular sieve.

[0067] Comparative Example 3

[0068] Weigh 1.0 g of 18-crown-6 and add it to 50 ml of N,N-dimethylformamide. Stir until the solid is completely dissolved. Then add 1.0 g of clinoptilolite and stir at room temperature for 12 hours. Filter, wash with deionized water, and dry to obtain crown-clinoptilolite.

[0069] Comparative Example 4

[0070] Add 1.0 g of clinoptilolite to 50 mL of 1 mol / L potassium chloride solution and heat with stirring at 80°C for 1 hour. Repeat the exchange twice, using fresh solution each time. Remove the supernatant by centrifugation, wash three times with deionized water, and dry in an oven at 105°C for 12 hours. The resulting solid is the potassium ion-exchange-modified clinoptilolite.

[0071] Test Case

[0072] Prepare Tl at a concentration of 1.0 ppm + The heavy metal solution was added to the adsorption material prepared in the above example at an addition rate of 1.0 g / L. The adsorption was carried out at 25°C and 200 r / min for 240 min. The water sample after adsorption was filtered with a 0.45 μm filter membrane, and the Tl content in the treated solution was determined by inductively coupled plasma mass spectrometry (ICP-MS). + The residual concentration of Tl + The removal rate of 2.5% is 2.3%, and the specific results are shown in Table 1.

[0073]

[0074] It can be seen from Table 1 that the crown ether-inorganic ion modified adsorption material provided by the present invention has a beneficial adsorption effect on thallium and a high removal rate.

[0075] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A method for preparing a crown ether-inorganic ion modified adsorption material, characterized in that: The method includes: (1) mixing a metal cation salt solution with an adsorption matrix material, performing ion exchange, and then drying to obtain an ion exchange modified sample; the adsorption matrix material is selected from at least one of activated carbon, biochar, molecular sieve, and carbon aerogel; and the metal cation salt is a potassium salt; (2) Immersing the ion exchange modified sample in an organic solvent containing a crown ether to obtain a crown ether-inorganic ion modified adsorption material; the crown ether is selected from at least one of 18-crown-6, aza-18-crown-6 and dibenzo-18-crown-6.

2. The method for preparing a crown ether-inorganic ion modified adsorption material according to claim 1, wherein: The concentration of the metal cation salt solution is 0.1-3 mol / L.

3. The method for preparing a crown ether-inorganic ion modified adsorption material according to claim 1, wherein: The metal cation salt is selected from at least one of potassium sulfate, potassium nitrate and potassium chloride.

4. The method for preparing a crown ether-inorganic ion modified adsorption material according to any one of claims 1 to 3, wherein: The liquid-to-solid ratio of the metal cation salt solution to the adsorption matrix material is 20-100 ml / g; And / or, the ion exchange conditions are: stirring speed of 100-500 rpm, reaction temperature of 25-95° C., reaction time of 1-8 h, and exchange times of at least 2 times.

5. The method for preparing a crown ether-inorganic ion modified adsorption material according to any one of claims 1 to 3, wherein: The concentration of the crown ether in the organic solvent is 10-100 g / L.

6. The method for preparing a crown ether-inorganic ion modified adsorption material according to any one of claims 1 to 3, wherein: The organic solvent is selected from at least one of N,N-dimethylformamide, dichloromethane, tetrahydrofuran, benzene and toluene.

7. The method for preparing a crown ether-inorganic ion modified adsorption material according to any one of claims 1 to 3, wherein: The liquid-to-solid ratio of the crown ether-containing organic solvent to the ion exchange modified sample is 20-100 ml / g.

8. The method for preparing a crown ether-inorganic ion modified adsorption material according to any one of claims 1 to 3, wherein: The impregnation conditions are: reaction time of 1 to 24 h, and reaction temperature of 25 to 80° C.

9. The crown ether-inorganic ion modified adsorption material prepared by the method according to any one of claims 1 to 8.

10. Use of the crown ether-inorganic ion modified adsorption material according to claim 9 as a thallium adsorption material.

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