A gallium ion selective adsorbent and a method for preparing the same

Abstract

The present application relates to a kind of gallium ion selective adsorbent and its preparation method.The present application is creatively synthesized a kind of novel structure hydroxyl functional zirconium-based organic metal framework material.The gallium ion selective adsorbent provided by the present application, by the introduction of more hydroxyl, make the surface electric property of adsorbent change from positive to negative, make the adsorbent obtain the electrostatic attraction to gallium ion, and by imprinting modification, significantly improve the adsorption capacity and selectivity of gallium ion, practically solve the problem of low selectivity adsorption performance of traditional adsorption material to gallium ion.The preparation method of the present application is simple, low cost, easy to realize industrial production, realizes the simple synthesis and recycling of adsorption material, further reduces the production cost, and harmful by-products are not produced in the synthesis process, is friendly to the environment, meets the green development concept.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of adsorption separation, in particular to a gallium ion selective adsorbent and a preparation method thereof. BACKGROUND

[0002] Due to the low content of gallium in the earth's crust and its existence in the form of associated minerals, the extraction process of gallium is relatively complex. At present, gallium is mainly extracted from gallium-containing minerals (such as bauxite, zinc ore, etc.) or gallium-containing waste liquid. The extraction process involves multiple steps such as leaching, separation, purification, etc., and requires the use of advanced chemical treatment and physical separation technology to ensure efficient and environmentally friendly extraction of high-purity gallium.

[0003] In the prior art, the separation of gallium ions mainly relies on solvent extraction, ion exchange and adsorption method. However, these methods have the following problems: (1) the organic solvent used in solvent extraction is harmful to the environment and the operation is complex; (2) the selectivity of ion exchange method is poor, and it is difficult to efficiently separate gallium ions from complex solutions; (3) the adsorption capacity of traditional adsorbents (such as activated carbon, silica gel, etc.) for gallium ions is limited. SUMMARY

[0004] In view of the above analysis, the embodiments of the present application aim to provide an adsorbent for selectively adsorbing gallium and a preparation method thereof, to solve the problems of poor selectivity, high cost, non-recyclable adsorbent, complex synthesis steps, and unsuitable for acidic conditions of the existing adsorbents for adsorbing and separating gallium.

[0005] The present application provides a preparation method of a gallium ion selective adsorbent for selectively adsorbing gallium from an aqueous solution, comprising the following steps:

[0006] S1, adding MOF-808-GA into a flask containing different volume ratios of water-methanol mixed solution, then adding gallium chloride solution, and stirring at room temperature for a certain time;

[0007] S2, slowly adding glutaraldehyde and potassium persulfate into the above mixture and continuously stirring the reaction;

[0008] S3, after the reaction is completed, the suspension is filtered and dried, and finally, the gallium template ions in the dried material are repeatedly eluted with hydrochloric acid solution until no Ga 3+ is detected in the filtrate;

[0009] S4, then the product after acid washing is further washed with deionized water to neutral, and vacuum drying at a certain temperature to obtain the target ion imprinted metal organic framework material MGI;

[0010] The preparation steps of MOF-808-GA are as follows:

[0011] (1) uniformly dispersing 1,3,5-benzenetricarboxylic acid (H3BTC) and zirconium oxychloride (ZrOCl2·8H2O) in a mixed solution of water and glacial acetic acid, and refluxing at a certain temperature;

[0012] (2) after the reaction is completed, collecting the generated white product, and washing with a large amount of ethanol and water for multiple times to remove residual raw materials;

[0013] (3) drying the product to obtain a finished MOF-808;

[0014] (4) dispersing the MOF-808 powder sample in a gluconic acid solution, and fully stirring at a certain temperature;

[0015] (5) after the stirring is completed, filtering the mixture, sequentially performing solvent exchange on the solid product using water and acetone, and then drying in a vacuum oven overnight to obtain MOF-808-GA.

[0016] Further, in the step (1), the molar mass ratio of 1,3,5-benzenetricarboxylic acid (H3BTC) and zirconium oxychloride (ZrOCl2·8H2O) is 3:1-5:1, the stirring reflux temperature is 85℃-100℃, and the reflux time can be 7h-10h.

[0017] Further, in the step (3), the drying temperature is 80℃-100℃, and the drying time is 24h-36h.

[0018] Further, in the step (4), the concentration of the gluconic acid solution is 400mmol / L-800mmol / L per gram of MOF-808; the stirring temperature is 70℃-90℃, and the stirring time is 12h-36h.

[0019] Further, in the step S1, the ratio of water to methanol is 9:1-5:5, the concentration of the gallium chloride solution is 300mg / L-500mg / L, and the stirring time is 15min-60min.

[0020] Further, in the step S2, the reaction temperature is 60℃-80℃, the amount of glutaraldehyde is 2mL-3mL, the mass ratio of potassium persulfate:MOF-808-GA is 1:1-1:3, and the reaction time is 4h-8h.

[0021] Further, in the step S3, the concentration of the elution hydrochloric acid is 0.5mol / L-1.5mol / L.

[0022] Further, in the step S4, the drying temperature is 60℃-80℃.

[0023] The application further provides a gallium ion selective adsorbent, which is an ion imprinted zirconium-based metal organic framework material for selectively separating gallium obtained by the above method.

[0024] Compared with the prior art, the application has the following beneficial effects:

[0025] 1. The application creatively synthesizes a novel structure of hydroxyl functionalized zirconium-based metal organic framework material.

[0026] 2. The gallium ion selective adsorbent provided by the application changes the surface electric property of the adsorbent from positive to negative by introducing more hydroxyl groups, so that the adsorbent obtains electrostatic attraction to gallium ions.

[0027] 3. The imprinted material significantly improves the adsorption capacity and selectivity of gallium ions, and practically solves the problem of low selectivity of traditional adsorbents to gallium ions.

[0028] 4. The preparation method is simple and low in cost, and is convenient for industrialized production.

[0029] 5. The simple synthesis and recycling of the adsorbent are realized, the production cost is further reduced, no harmful by-products are generated in the synthesis process, the environment is friendly, and the green development concept is met.

[0030] The above technical solutions can be combined with each other to realize more preferred combination solutions. Other features and advantages of the application will be described in the subsequent specification, and some advantages will become apparent from the specification, or will be understood by implementing the application. The purposes and other advantages of the application can be realized and obtained from the contents specifically pointed out in the specification and the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings are included to provide a further understanding of the application and are incorporated herein and constitute a part of the application. The drawings illustrate embodiments of the application and, together with the description, serve to explain the principles of the application. In the drawings:

[0032] Figure 1 The preparation flowchart of the adsorbent synthesized by the application;

[0033] Figure 2 The X-ray diffraction analysis diagram of the adsorbent of the application;

[0034] Figure 3 The scanning electron microscope diagram of the adsorbent of the application;

[0035] Figure 4 The infrared spectrum diagram of the adsorbent of the application and the gallium adsorption performance diagram;

[0036] Figure 5Adsorption and desorption curves and pore size curves of the adsorbent of the present application under nitrogen at 77K;

[0037] Figure 6 Zeta potential diagram of the adsorbent of the present application at different pH values;

[0038] Figure 7 Selective adsorption result diagram of the adsorbent of the present application;

[0039] Figure 8 Schematic diagram of the adsorbent of the present application capturing gallium ions.

[0040] The above merely provides the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which shall be covered within the protection scope of the present application. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the person skilled in the art without creative labor shall be covered within the protection scope of the present application.

[0042] In order to make the content described in the present application easier to understand, the adsorbent described in the present application will be further described in combination with the specific embodiments, but the present application is not limited by any means.

[0043] The present application provides a preparation method of a gallium ion selective adsorbent for selectively adsorbing gallium from an aqueous solution, which comprises the following steps, and the synthesis flow chart is shown in Figure 1 :

[0044] S1, adding hydroxylated MOF-808 (hereinafter referred to as MOF-808-GA) to a flask containing different volume ratios of water-methanol mixed solution, then adding gallium chloride solution, and stirring at room temperature for a certain time;

[0045] S2, slowly adding glutaraldehyde and potassium persulfate to the above mixture and continuously stirring the reaction;

[0046] S3, after the reaction is completed, the suspension is filtered and dried. Finally, the gallium template ions in the dried material are repeatedly eluted with hydrochloric acid solution until no Ga 3+ ;

[0047] S4, then the product after acid washing is further washed with deionized water to neutral, and the target ion imprinted metal organic framework material MGI is obtained by vacuum drying under certain temperature conditions.

[0048] The MOF-808-GA preparation steps are as follows:

[0049] Step (1) uniformly disperse 1,3,5-benzenetricarboxylic acid (H3BTC) and zirconium oxychloride octahydrate (ZrOCl2·8H2O) in a mixed solution of water and glacial acetic acid, and reflux at a certain temperature;

[0050] Step (2) after the reaction is completed, collect the generated white product, and wash with a large amount of ethanol and water for multiple times to remove residual raw materials;

[0051] Step (3) dry the product to obtain finished product MOF-808;

[0052] Step (4) disperse the MOF-808 powder sample in a gluconic acid solution, and fully stir at a certain temperature;

[0053] Step (5) after the stirring is completed, filter the mixture, sequentially use water and acetone to solvent exchange the solid product, and then dry in a vacuum oven overnight to obtain MOF-808-GA;

[0054] In the step (1), the molar mass ratio of 1,3,5-benzenetricarboxylic acid (H3BTC) and zirconium oxychloride octahydrate (ZrOCl2·8H2O) can be 3:1-5:1, preferably 3:1;

[0055] In the step (1), the stirring reflux temperature can be 85℃-100℃, preferably 95℃;

[0056] In the step (1), the reflux time can be 7h-10h;

[0057] In the step (3), the drying temperature can be 80℃-100℃, and the drying time can be 24h-36h;

[0058] In the step (4), the concentration of the gluconic acid solution can be 400mmol / L-800mmol / L per gram of MOF-808, preferably 600mmol / L;

[0059] In the step (4), the stirring temperature can be 70℃-90℃, preferably 75℃;

[0060] In the step (4), the stirring time can be 12h-36h, preferably 24h;

[0061] In the step S1, the ratio of water to methanol can be 9:1-5:5, preferably 8:2;

[0062] The concentration of the gallium chloride solution in the step S1 can be 300 mg / L-500 mg / L;

[0063] The stirring time in the step S1 can be 15 min-60 min, preferably 30 min;

[0064] The reaction temperature in the step S2 can be 60℃-80℃;

[0065] The amount of glutaraldehyde in the step S2 can be 2 mL-3 mL, preferably 2.75 mL;

[0066] The mass ratio of potassium persulfate:MOF-808-GA in the step S2 can be 1:1-1:3, preferably 1:1;

[0067] The reaction time in the step S2 can be 4h-8h, preferably 5h;

[0068] The concentration of the elution hydrochloric acid in the step S3 can be 0.5 mol / L-1.5 mol / L;

[0069] The drying temperature in the step S4 can be 60℃-80℃;

[0070] The application also provides a gallium ion selective adsorbent, which is an ion imprinted zirconium-based metal organic framework material for selectively separating gallium obtained by the above method.

[0071] Example 1

[0072] Synthesis method of hydroxyl functionalized MOF-808:

[0073] 1. In a 250 mL round-bottom flask, 2.8 g of 1,3,5-benzenetricarboxylic acid (H3BTC) and 12.88 g of zirconium oxychloride octahydrate (ZrOCl2·8H2O) were uniformly dispersed in a mixed solution of 100 mL of water and 100 mL of glacial acetic acid (AA). Then, the mixed solution was refluxed at 90℃ for 8 hours.

[0074] 2. After the reaction was completed, the generated white product was collected and washed with a large amount of ethanol and water for several times to remove the residual raw materials.

[0075] 3. Then, the product was dried at 100℃ for 24h to obtain the finished product.

[0076] 4. 0.4665 g of MOF-808 powder sample was dispersed in a 300 mmol / L solution of gluconic acid, and stirred at 75℃ for 24h.

[0077] 5. After the end of stirring, the mixture was filtered, and the solid product was subjected to solvent exchange using water (3 times x 50 mL) and acetone (3 times x 50 mL) in sequence, and then dried in a vacuum oven at a temperature of 90°C overnight.

[0078] Example 2

[0079] Synthesis method of ion imprinted MOF-808-GA:

[0080] 1. 1 g MOF-808-GA was added to a 250 mL flask containing 100 mL of a mixed solution of water-methanol in a volume ratio of 8:2, then 1 mL of a gallium chloride solution with a concentration of 300 mg / L was added, and after stirring at room temperature for 30 min,

[0081] 2. Different doses of 2.75 mL glutaraldehyde and 0.2 g potassium persulfate were slowly added to the above mixture at 70°C, and the stirring reaction was continued for 5 h,

[0082] 3. After the reaction was completed, the suspension was filtered and dried. Finally, the gallium template ions in the dried product were repeatedly eluted with a 1 mol / L hydrochloric acid solution until no Ga 3+ ,

[0083] 4. The product after acid washing was further washed with deionized water to neutral, and vacuum dried at a temperature of 60°C for 24 h to obtain the target ion imprinted metal organic framework material MGI.

[0084] Example 3

[0085] Characterization test of MGI:

[0086] 1. The XRD patterns of MGI and hydroxylated MOF-808 and original MOF-808 are shown in Figure 2 , all of which have the same peak shape, and the positions and intensities of the diffraction peaks are highly consistent, indicating that the modification does not cause significant damage to the crystal structure.

[0087] 2. The SEM pattern of MGI is shown in Figure 3 , and the MGI adsorbent surface appears many uniform pores and some irregular pores. The appearance of uniform pores is due to the removal of template ions, and the irregular pores are due to H2O in the solvent participating in the synthesis process in the form of bound water together with Ga 3+ , and the evaporation of H2O during the drying process makes the imprinted pore size larger, and on the other hand, because some components of the polymer are not completely polymerized and cross-linked, they are removed together with Ga 3+ during the acid washing process. In addition, MGI shows a more uneven appearance structure compared to MGN, which is because Ga 3+After interacting with MOF-808-GA, it occupies certain hydroxyl binding sites, making the sites where glutaraldehyde can interact no longer uniform. Overall, SEM shows that the MGI surface has a rich porous structure, and the imprinted layer covers the substrate relatively uniformly.

[0088] 3. Infrared spectra of MGI, hydroxylated MOF-808, and pristine MOF-808 are shown below. Figure 4 As shown, the infrared spectrum of MGI is at 1161 cm⁻¹ -1 and 1670cm -1 A new absorption peak related to the C=O and CO stretching vibrations of glutaraldehyde appeared at the Ga content, indicating that glutaraldehyde had been successfully loaded onto the raw material surface. In contrast, the spectra of MGI and MOF-808-GA showed the same main peak at similar positions, indicating that the imprinting process had little effect on the main structure of the imprinted material. Furthermore, in Ga... 3+ After the imprint, 1080cm -1 The -OH peak weakens at 1285 cm⁻¹ -1 A new peak appears, indicating that during the synthesis of the imprinted layer, the hydroxyl group of gluconic acid and the aldehyde group of glutaraldehyde underwent an aldol condensation reaction on the MGI surface.

[0089] 4. Adsorption-desorption curves and pore size curves of MGI, hydroxylated MOF-808, and pristine MOF-808 under nitrogen at 77 K are shown below. Figure 5 As shown, based on the adsorption isotherm classification, the adsorption curve of MGI conforms to the type I isotherm, exhibiting microporous characteristics. Compared to MOF-808 and MOF-808-GA, its N2 adsorption capacity is further reduced, and pore size distribution peaks are observed at 0.6 nm and 0.7 nm, indicating that micropores are predominantly present in the sample. The specific surface area of ​​MGI is calculated to be 479.12 m² using the BET method. 2 / g.

[0090] 5. Zeta potentials of MGI, hydroxylated MOF-808, and pristine MOF-808 at different pH values, such as... Figure 6 As shown, its value is related to the pH of the solution. The negative value of the Zeta potential indicates the presence of vacant hydroxyl groups. Furthermore, the MGI surface remains negatively charged in all solution environments, which also reveals the interaction between MGI and Ga. 3+ The interactions between them will also include electrostatic effects.

[0091] Example 4

[0092] A method for selectively separating gallium from a mixed ionic solution, such as Figure 8 As shown, the specific steps include the following:

[0093] 1. Take a 100 mL volumetric flask, and prepare a mixed solution of Al(NO3)3.9H2O, Zn(NO3)2.6H2O, Ga(NO3)3.9H2O with a concentration range of 30 mg / L to 90 mg / L;

[0094] 2. Accurately weigh 100 mg of the adsorbent with an electronic balance, and place it in a beaker. Then, adjust the pH value of the solution using hydrochloric acid and sodium hydroxide. After adjusting the pH value, rinse the measuring cylinder twice with the gallium solution, and then accurately measure 50 mL of the mixed solution with the measuring cylinder and pour it into another new beaker;

[0095] 3. Place the conical flask containing the adsorbent and the mixed solution as the adsorbate on a constant temperature stirring table, start timing, and set the adsorption time to 8 h, with the adsorption temperature kept at 25℃.

[0096] The results are shown in Table 1. Figure 7 As shown in Table 1, when the total concentration of the Al / Ga / Zn system is gradually increased from 30 mg / L to 90 mg / L, the adsorption rate of Ga 3+ increases from 57.93% to 84.33%, while the adsorption rate of Al 3+ on MGI has a rising trend, but the rising amplitude is always controlled within 12%.

[0097] The present application has the following beneficial effects: 1. The present application creatively synthesizes a novel structure of hydroxyl functionalized zirconium-based organic metal framework material. 2. The gallium ion selective adsorbent provided by the present application changes the surface electrical property of the adsorbent from positive to negative by introducing more hydroxyl groups, so that the adsorbent obtains electrostatic attraction to gallium ions. 3. The adsorption capacity and selectivity of gallium ions are significantly improved, and the problem of low selectivity of traditional adsorbents for gallium ions is solved. 4. The preparation method is simple and low in cost, and is convenient for industrialized production. 5. The simple synthesis and recycling of the adsorbent are realized, the production cost is further reduced, and no harmful by-products are produced in the synthesis process, which is friendly to the environment and conforms to the green development concept.

[0098] The technical features of the above-described embodiments can be combined in any manner. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not exist, they should be considered as within the scope of the present disclosure.

[0099] The above described embodiments only express the implementation of the present application, the description is more specific and detailed, but it cannot be understood as the limitation of the patent scope of the present application. It should be noted that for ordinary skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method for preparing a gallium ion selective adsorbent, wherein the adsorbent is used for selective adsorption of gallium in an aqueous solution, characterized in that: Includes the following steps: S1. Add MOF-808-GA to flasks containing water-methanol mixtures of different volume ratios, then add gallium chloride solution and stir at room temperature for a certain period of time. S2. Slowly add glutaraldehyde and potassium persulfate to the above mixture and continue stirring to react; S3. After the reaction is complete, filter and dry the suspension. Finally, repeatedly elute the dried material with hydrochloric acid solution to remove gallium template ions until no Ga is detected in the filtrate. 3+ ; S4. Subsequently, the acid-washed product was further washed with deionized water until neutral, and then vacuum dried under certain temperature conditions to obtain the target ion-imprinted metal-organic framework material MGI. The preparation steps of MOF-808-GA are as follows: (1) The zirconium oxychloride octahydrate (ZrOCl2・8H2O) of 1,3,5-pyromellitic tricarboxylic acid (H3BTC) was uniformly dispersed in a mixed solution of water and glacial acetic acid, and the reaction was refluxed at a certain temperature; (2) After the reaction is complete, the white product generated is collected and washed repeatedly with a large amount of ethanol and water to remove residual raw materials; (3) The product is dried to obtain the finished product MOF-808; (4) Disperse the MOF-808 powder sample in gluconic acid solution and stir thoroughly at a certain temperature; (5) After stirring, the mixture was filtered, and the solid product was successively solvent-exchanged with water and acetone. Then it was dried overnight in a vacuum oven to obtain MOF-808-GA.

2. The method according to claim 1, characterized in that: In step (1), the molar mass ratio of 1,3,5-tristyric acid (H3BTC) and zirconium oxychloride octahydrate (ZrOCl2・8H2O) is 3:1-5:1, the stirring and reflux temperature is 85℃-100℃, and the reflux time is 7 h-10 h.

3. The method according to claim 2, characterized in that: In step (3), the drying temperature is 80℃-100℃ and the drying time is 24 h-36 h.

4. The method according to claim 1, characterized in that: In step (4), the concentration of gluconic acid solution is 400 mmol / L-800 mmol / L per gram of MOF-808; the stirring temperature is 70℃-90℃; and the stirring time is 12 h-36 h.

5. The method according to claim 1, characterized in that: In step S1, the ratio of water to methanol is 9:1 to 5:5, the concentration of gallium chloride solution is 300 mg / L to 500 mg / L, and the stirring time is 15 min to 60 min.

6. The method according to claim 1, characterized in that: In step S2, the reaction temperature is 60℃-80℃, the amount of glutaraldehyde is 2 mL-3 mL, the mass ratio of potassium persulfate to MOF-808-GA is 1:1-1:3, and the reaction time is 4 h-8 h.

7. The method according to claim 1, characterized in that: In step S3, the concentration of eluting hydrochloric acid is 0.5 mol / L to 1.5 mol / L.

8. The method according to claim 1, characterized in that: In step S4, the drying temperature is 60℃-80℃.

9. A gallium ion selective adsorbent, characterized in that: The adsorbent is an ion-imprinted zirconium-based metal-organic framework material for selective gallium separation obtained by the method according to any one of claims 1-8.

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