Magnesium-based aerogel material as well as preparation method and application thereof

Abstract

The invention relates to a magnesium-based aerogel material as well as a preparation method and application thereof, and belongs to the field of electrochemistry. The method comprises the following steps: step 1, diluting the Mg < 2 + >-containing low-sodium carnallite decomposition mother liquor to obtain diluted low-sodium carnallite decomposition mother liquor; 2, preparing a sodium borohydride solution with the concentration of 0.1 mol / L to 0.3 mol / L; and step 3, injecting a sodium borohydride solution into a mixed solution of the salt solution of the metal M or the combined salt solution of the metal M and the diluted low-sodium carnallite decomposition mother liquor, reacting, centrifuging and freeze-drying to obtain the magnesium-based aerogel material of the metal M. The MgNiCe aerogel material prepared by the method is uniform in morphology and stable in structure, and Mg < 2 + > in the low-sodium carnallite decomposition mother liquor can be efficiently extracted and adsorbed. The technical scheme has universality and is suitable for extracting magnesium ions from Qinghai salt lake resources, and a new solution is provided for comprehensive utilization of salt lake magnesium resources.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrochemistry, and particularly relates to a magnesium-based aerogel material, a preparation method thereof, and an application thereof. Background Art

[0002] China is rich in salt lake resources and is one of the countries with the most salt lakes in the world. Carnallite is formed by the evaporation and crystallization of salt lake brine and is the most basic and high-yielding mineral in salt lakes. The cold decomposition strategy of carnallite is a relatively mature technology for producing potassium chloride potassium fertilizer from carnallite. However, due to its low yield and the production of carnallite decomposition liquid containing a large amount of magnesium chloride by-products during the production process, the decomposition liquid is discharged back into the salt lake, which not only causes serious waste of resources but also affects the sustainable production of potassium fertilizer.

[0003] In recent years' research, aerogels have shown great application potential in the fields of environmental governance, resource recovery, etc. due to their unique porous structure and high specific surface area. Especially in the development of salt lake resources, aerogels are widely used for adsorbing and removing various ions, such as lithium, boron, etc., while there are very few reports on articles about adsorbing magnesium ions. Moreover, in the past few decades, metal aerogels have also shown great potential as single-functional or dual-functional electrocatalytic materials in electrochemical energy storage and conversion.

[0004] Therefore, it is urgent to develop effective methods and strategies to treat the carnallite decomposition liquid containing a large amount of magnesium chloride by-products and prepare a novel magnesium-based aerogel adsorbent that can extract and adsorb Mg 2+ in order to provide theoretical and technical support for the rational design of high-capacity adsorbents and the study of adsorption mechanisms. Summary of the Invention

[0005] The present invention provides a magnesium-based aerogel material, a preparation method thereof, and an application thereof to solve the technical problem of efficient separation and resource utilization of magnesium ions Mg 2+ in salt lake resources.

[0006] The present invention provides a preparation method of a magnesium-based aerogel material, including:

[0007] Step 1: Dilute the low-sodium carnallite decomposition mother liquor containing Mg 2+ to obtain a diluted low-sodium carnallite decomposition mother liquor;

[0008] Step 2: Prepare a sodium borohydride solution with a concentration of 0.1 - 0.3 mol / L;

[0009] Step 3: Inject the sodium borohydride solution into a mixed solution of a metal M salt solution or its combined salt solution and the diluted low-sodium carnallite decomposition mother liquor, carry out a reaction, centrifuge, and freeze-dry to obtain a metal M magnesium-based aerogel material.

[0010] The present invention also provides a magnesium-based aerogel material of metal M prepared by the above preparation method.

[0011] The present invention further provides an application of the magnesium-based aerogel material of metal M in the adsorption and removal of metal ions, where the metal M is Ni, Ce, Fe, Co, or Cu.

[0012] The present invention provides a magnesium-based aerogel material and a preparation method thereof. By means of the sol-gel method and freeze-drying technology, magnesium element is successfully incorporated into the aerogel to form a magnesium-based aerogel material composed of magnesium-cerium alloy, nickel oxyhydroxide, and cerium dioxide. This material has the following technical effects:

[0013] Efficient magnesium removal: Using the decomposed mother liquor of low-sodium carnallite as the magnesium source, magnesium ions are removed synergistically by a two-step method. For the first time, the concentration of magnesium ions in the decomposed mother liquor is reduced by 98.5%. Subsequently, through secondary adsorption by the aerogel, the concentration of magnesium ions is finally reduced by 99.5%, achieving efficient removal of magnesium ions.

[0014] Resource utilization: By successfully incorporating magnesium element into the aerogel, secondary utilization of magnesium resources in salt lakes is realized, solving the problem of waste of magnesium resources.

[0015] Uniform material morphology: The prepared magnesium-based aerogel material shows a nano-linear structure formed by cross-linking of aerogel nanoparticles at the microscopic level. The diameter of the spherical particles is between 50 and 200 nm, with uniform morphology and stable structure.

[0016] Environmentally friendly and efficient: This method has a simple process, convenient operation, and is environmentally friendly, providing a new way for the efficient utilization of magnesium resources in salt lakes.

[0017] In summary, through the innovative magnesium-based aerogel material and its preparation method of the present invention, efficient separation and resource utilization of magnesium resources in salt lakes are achieved, with significant economic and environmental benefits.

[0018] Traditional methods are difficult to achieve efficient removal and reasonable conversion of magnesium ions, resulting in waste of magnesium resources and environmental pollution. Through the innovative magnesium-based aerogel material and its preparation method of the present invention, efficient removal of magnesium ions and secondary utilization of magnesium resources in salt lakes are realized, providing an efficient and environmentally friendly solution for the development of salt lake resources. Description of the Drawings

[0019] Figure 1 is the preparation flow chart of the magnesium-based aerogel material of the present invention;

[0020] Figure 2 is the scanning electron microscope photograph of the magnesium-based aerogel material of the present invention;

[0021] Figure 3XRD pattern of the magnesium-based aerogel material of the present invention. Detailed implementation mode

[0022] The present invention is illustrated by the following examples.

[0023] The Mg2+-containing carnallite decomposition mother liquor used in the present invention can be prepared in the laboratory by itself or obtained through the cold decomposition strategy of carnallite.

[0024] Example 1

[0025] Preparation of magnesium-based aerogel material:

[0026] (1) Dissolve nickel sulfate and cerium chloride in water: Weigh 1.31 g of nickel sulfate hexahydrate and 1.23 g of cerium chloride, add them to a 100 mL beaker respectively, and add 50 mL of deionized water to dissolve them. The concentrations of nickel sulfate and cerium chloride solutions are 0.1 mol / L.

[0027] (2) Cold decomposition of low-sodium carnallite: In a reaction vessel with a stirring device and temperature control, add 40% of the weight of carnallite of water to low-sodium carnallite. The stirring speed is controlled at 100 - 200 rpm / min to ensure that carnallite can be evenly dispersed and fully reacted. The reaction temperature needs to be strictly controlled at 25 °C. After reacting for a period of time, solid potassium chloride precipitation will appear in the solution. Solid-liquid separation is carried out by suction filtration to obtain the preliminarily separated potassium chloride solid and the mother liquor containing magnesium chloride and other substances. The separated potassium chloride solid is washed with a small amount of cold water to remove the impurities and mother liquor attached to the surface. The number of washing times is generally 2 - 3 times, and the amount of water used for each washing is controlled to cover the solid surface, further improving the purity of potassium chloride.

[0028] (3) Preparation of magnesium-based aerogel by sol-gel method: Dilute the mother liquor of low-sodium carnallite decomposition rich in Mg 2+ to 50 mL, and control the concentration of Mg 2 in the diluted solution to be 0.1 mol / L. Weigh 0.19 g of sodium borohydride into a 100 mL beaker, add 50 mL of deionized water to dissolve it, and obtain a freshly prepared sodium borohydride solution with a concentration of 0.1 mol / L. Mix the nickel sulfate, cerium chloride solutions and the diluted mother liquor of low-sodium carnallite decomposition by ultrasonic. Rapidly inject the freshly prepared sodium borohydride solution into the previous mixed solution.

[0029] (4) Obtain the target product after centrifugal separation and drying treatment: Centrifuge the above suspension at 900 rpm for 10 minutes, then wash it three times with water and centrifuge it, and obtain the target product MgNiCe aerogel after freeze-drying.

[0030] Example 2

[0031] Preparation of magnesium-based aerogel material:

[0032] (1) Dissolve nickel sulfate and cerium chloride in water: Weigh 1.31 g of nickel sulfate hexahydrate and 1.23 g of cerium chloride, and add them to a 100 mL beaker respectively. Add 50 mL of deionized water to each for dissolution. The concentrations of the nickel sulfate and cerium chloride solutions are 0.1 mol / L.

[0033] (2) Cold decomposition of low-sodium carnallite: In a reaction vessel equipped with a stirring device and temperature control, add water equal to 40% of the weight of the low-sodium carnallite to the low-sodium carnallite. Control the stirring speed at 100 - 200 rpm / min to ensure that the carnallite can be evenly dispersed and fully react. The reaction temperature needs to be strictly controlled at 25 °C. After reacting for a period of time, solid potassium chloride precipitates will appear in the solution. Perform solid-liquid separation by suction filtration to obtain preliminarily separated potassium chloride solid and mother liquor containing substances such as magnesium chloride. Wash the separated potassium chloride solid with a small amount of cold water to remove the impurities and mother liquor attached to the surface. The number of washing times is generally 2 - 3 times, and the amount of water used for each wash is controlled to cover the surface of the solid, further improving the purity of potassium chloride.

[0034] (3) Preparation of magnesium-based aerogel by sol-gel method: Dilute the mother liquor of low-sodium carnallite decomposition to 50 mL, and control the concentration of Mg 2+ in the dilution solution to be 0.1 mol / L. Weigh 0.19 g of sodium borohydride into a 100 mL beaker, add 50 mL of deionized water for dissolution to obtain a freshly prepared sodium borohydride solution with a concentration of 0.3 mol / L. Mix the nickel sulfate, cerium chloride solutions and the diluted mother liquor of low-sodium carnallite decomposition by ultrasound. Rapidly inject the freshly prepared sodium borohydride solution into the previous mixed solution. 2

[0035] (4) Obtain the target product after centrifugal separation and drying treatment: Centrifuge the above suspension at 900 rpm for 10 minutes, then wash it three times with water and centrifuge again, and obtain the target product MgNiCe aerogel after freeze-drying.

[0036] Example 3

[0037] Preparation of magnesium-based aerogel material:

[0038] (1) Dissolve nickel sulfate in water: Weigh 1.31 g of nickel sulfate hexahydrate and add it to a 100 mL beaker, add 50 mL of deionized water for dissolution, and the concentration of the nickel sulfate solution is 0.1 mol / L.

[0039] ​(2) Cold decomposition of low sodium carnallite: In a reaction vessel equipped with a stirring device and temperature control, add 40% of the weight of carnallite to the low sodium carnallite. The stirring speed is controlled at 100-200 rpm / min to ensure that the carnallite can be evenly dispersed and fully reacted. The reaction temperature must be strictly controlled at 25°C. After a period of reaction, solid potassium chloride precipitates will appear in the solution. Use suction filtration to separate the solid and liquid to obtain a preliminarily separated potassium chloride solid and a mother liquor containing magnesium chloride and other substances. The separated potassium chloride solid is washed with a small amount of cold water to remove impurities and mother liquor attached to the surface. The number of washings is generally 2-3 times, and the amount of water used for each washing is controlled to cover the solid surface, thereby further improving the purity of potassium chloride.

[0040] (3) Preparation of magnesium-based aerogel by sol-gel method: Mg-rich 2+ The low sodium carnallite decomposition mother liquor was diluted to 50 mL, and the Mg content in the dilution was controlled. 2 The concentration is 0.1 mol / L. Weigh 0.19 g of sodium borohydride into a 100 mL beaker and add 50 mL of deionized water to dissolve to obtain a freshly prepared sodium borohydride solution with a concentration of 0.1 mol / L. Ultrasonicate the nickel sulfate solution and the diluted low-sodium carnallite decomposition mother liquor. Quickly inject the freshly prepared sodium borohydride solution into the previous mixed solution.

[0041] (4) The target product was obtained after centrifugal separation and drying: the suspension was centrifuged at 900 rpm for 10 minutes, washed three times with water and centrifuged, and freeze-dried to obtain the target product MgNi aerogel.

[0042] Example 4

[0043] Preparation of magnesium-based aerogel materials:

[0044] (1) Dissolve ferric nitrate in water: weigh 2.02 g of ferric nitrate nonahydrate and add it to a 100 mL beaker. Add 50 mL of deionized water to dissolve the ferric nitrate solution. The concentration of the ferric nitrate solution is 0.1 mol / L.

[0045] (2) Cold decomposition of low sodium carnallite: In a reaction vessel equipped with a stirring device and temperature control, add 40% of the weight of carnallite to the low sodium carnallite. The stirring speed is controlled at 100-200 rpm / min to ensure that the carnallite can be evenly dispersed and fully reacted. The reaction temperature must be strictly controlled at 25°C. After a period of reaction, solid potassium chloride precipitates will appear in the solution. Use suction filtration to separate the solid and liquid to obtain a preliminarily separated potassium chloride solid and a mother liquor containing magnesium chloride and other substances. The separated potassium chloride solid is washed with a small amount of cold water to remove impurities and mother liquor attached to the surface. The number of washings is generally 2-3 times, and the amount of water used for each washing is controlled to cover the solid surface, thereby further improving the purity of potassium chloride.

[0046] (3) Preparation of magnesium-based aerogel by sol-gel method: Dilute the mother liquor of the decomposition of carnallite with low sodium content to 50 mL, and control the concentration of Mg in the diluted solution 2+ to be 0.1 mol / L. Weigh 0.19 g of sodium borohydride into a 100 mL beaker, add 50 mL of deionized water to dissolve it, and obtain a freshly prepared sodium borohydride solution with a concentration of 0.1 mol / L. Mix the iron nitrate solution and the diluted mother liquor of the decomposition of carnallite with low sodium content and ultrasonicate. Rapidly inject the freshly prepared sodium borohydride solution into the previous mixed solution. 2

[0047] (4) Obtain the target product after centrifugal separation and drying treatment: Centrifuge the above suspension at 900 rpm for 10 minutes, then wash it three times with water and centrifuge again, and obtain the target product MgFe aerogel after freeze-drying.

[0048] Example 5

[0049] Preparation of magnesium-based aerogel material:

[0050] (1) Dissolve cobalt nitrate in water: Weigh 1.45 g of cobalt nitrate hexahydrate and add it to a 100 mL beaker, add 50 mL of deionized water to dissolve it, and the concentration of the cobalt nitrate solution is 0.1 mol / L.

[0051] (2) Cold decomposition of carnallite with low sodium content: In a reaction vessel equipped with a stirring device and temperature control, add water with a weight of 40% of the carnallite itself to the carnallite with low sodium content. Control the stirring speed at 100 - 200 rpm / min to ensure that the carnallite can be evenly dispersed and fully react. The reaction temperature needs to be strictly controlled at 25 °C. After reacting for a period of time, solid potassium chloride precipitate will appear in the solution. Perform solid-liquid separation by suction filtration to obtain the preliminarily separated potassium chloride solid and the mother liquor containing magnesium chloride and other substances. Wash the separated potassium chloride solid with a small amount of cold water to remove the impurities and mother liquor attached to the surface. The number of washing times is generally 2 - 3 times, and the amount of water used for each washing is controlled to cover the solid surface, so as to further improve the purity of potassium chloride.

[0052] (3) Preparation of magnesium-based aerogel by sol-gel method: Dilute the mother liquor of the decomposition of carnallite with low sodium content to 50 mL, and control the concentration of Mg in the diluted solution 2+ to be 0.1 mol / L. Weigh 0.19 g of sodium borohydride into a 100 mL beaker, add 50 mL of deionized water to dissolve it, and obtain a freshly prepared sodium borohydride solution with a concentration of 0.1 mol / L. Mix the cobalt nitrate solution and the diluted mother liquor of the decomposition of carnallite with low sodium content and ultrasonicate. Rapidly inject the freshly prepared sodium borohydride solution into the previous mixed solution. 2

[0053] ​​(4) Obtain the target product after centrifugal separation and drying: Centrifuge the above suspension at 900 rpm for 10 minutes, then wash it three times with water and centrifuge again. After freeze-drying, the target product MgCo aerogel is obtained.

[0054] Example 6

[0055] Preparation of magnesium-based aerogel material:

[0056] (1) Dissolve copper nitrate in water: Weigh 0.94 g of copper nitrate and add it to a 100 mL beaker. Add 50 mL of deionized water to dissolve it. The concentration of the copper nitrate solution is 0.1 mol / L.

[0057] (2) Cold decomposition of low-sodium carnallite: In a reaction vessel equipped with a stirring device and temperature control, add water equal to 40% of the weight of carnallite to the low-sodium carnallite. Control the stirring speed at 100 - 200 rpm / min to ensure that the carnallite can be evenly dispersed and fully react. The reaction temperature needs to be strictly controlled at 25 °C. After reacting for a period of time, solid potassium chloride precipitation will appear in the solution. Use suction filtration for solid-liquid separation to obtain the preliminarily separated potassium chloride solid and the mother liquor containing substances such as magnesium chloride. Wash the separated potassium chloride solid with a small amount of cold water to remove the impurities and mother liquor adhering to the surface. The number of washing times is generally 2 - 3 times, and the amount of water used for each washing is controlled to cover the solid surface, further improving the purity of potassium chloride.

[0058] (3) Prepare magnesium-based aerogel by sol-gel method: Dilute the mother liquor of low-sodium carnallite decomposition rich in Mg 2+ to 50 mL, and control the concentration of Mg 2 in the diluted solution to be 0.1 mol / L. Weigh 0.19 g of sodium borohydride into a 100 mL beaker, add 50 mL of deionized water to dissolve it, and obtain a freshly prepared sodium borohydride solution with a concentration of 0.1 mol / L. Mix the copper nitrate solution and the diluted mother liquor of low-sodium carnallite decomposition and ultrasonicate. Rapidly inject the freshly prepared sodium borohydride solution into the previous mixed solution.

[0059] (4) Obtain the target product after centrifugal separation and drying: Centrifuge the above suspension at 900 rpm for 10 minutes, then wash it three times with water and centrifuge again. After freeze-drying, the target product MgCu aerogel is obtained.

[0060] Conclusion analysis:

[0061] According to the appendix Figure 1 and the appendix Figure 2 It can be seen that the magnesium-based aerogel material prepared by the technical solution provided by the present invention shows a nano-linear structure formed by the cross-linking of aerogel nanoparticles at the microscopic level, and the diameter of the spherical particles is about between 50 - 200 nm. Therefore, the morphology of the magnesium-based material prepared by the technical solution of the present invention is uniform.

[0062] According to the attached Figure 3 It can be further seen that the magnesium-based aerogel material prepared by the present invention is composed of three different substances: magnesium-cerium alloy, nickel oxyhydroxide, and cerium dioxide, which proves that magnesium elements are successfully incorporated into the aerogel, realizing the secondary utilization of magnesium resources in salt lakes.

[0063] Applications of magnesium-based aerogel:

[0064] According to Table 1, the mother liquor of the decomposition of low-sodium carnallite, the supernatant after centrifugation of the magnesium-based aerogel material prepared by the sol-gel method, and the magnesium-based aerogel material prepared is redissolved into the supernatant to adsorb the remaining Mg 2+ concentration, the Mg 2+ concentration comparison table shows that

[0065] Table 1: Mother liquor of the decomposition of low-sodium carnallite, the centrifugate after the preparation of the magnesium-based aerogel material by the sol-gel method, and the Mg 2+ concentration in the solution after the magnesium-based aerogel material prepared is redissolved into the centrifugate to adsorb the remaining Mg 2+ concentration comparison table

[0066]

[0067]

[0068] The present invention uses the mother liquor of the cold decomposition of low-sodium carnallite as the magnesium source to synthesize magnesium-based aerogel, which can initially reduce the magnesium ion concentration in the mother liquor by 98.5%. Subsequently, the freeze-dried aerogel is used to adsorb magnesium ions in the supernatant again to achieve secondary magnesium reduction, and the magnesium ion concentration is finally reduced by 99.5%. Therefore, the magnesium-based material prepared by the technical solution of the present invention can realize the reasonable conversion and utilization of magnesium resources in salt lakes.

Claims

1. A method for preparing a magnesium-based aerogel material, characterized in that: include: Step 1: Add Mg 2+ diluting the low-sodium carnallites decomposition mother liquor to obtain a diluted low-sodium carnallites decomposition mother liquor; Step 2: Prepare a sodium borohydride solution with a concentration of 0.1 to 0.3 mol / L; Step 3: injecting the sodium borohydride solution into the mixed solution of the salt solution of metal M or its combined salt solution and the diluted low-sodium carnallite decomposition mother liquor, reacting, centrifuging and freeze-drying to obtain the magnesium-based aerogel material of metal M.

2. The method according to claim 1, characterized in that When the metal M is Ni or Ce, the salt solution of the metal M is nickel sulfate or cerium chloride; when the metal is Ni, the salt solution of the metal M is nickel sulfate solution; when the metal is Fe, the salt solution of the metal M is iron nitrate; when the metal is Co, the salt solution of the metal M is cobalt nitrate; when the metal is Cu, the salt solution of the metal M is copper nitrate.

3. The method according to claim 2, characterized in that The concentration of the metal M salt solution is 0.1 mol / L.

4. The method according to claim 1, characterized in that: Step 1 includes: Step 11: In a reaction vessel equipped with a stirring device and temperature control, low sodium carnallite and deionized water are added in a certain proportion; Step 12: Start stirring, and control the stirring speed at 100-200 rpm / min to ensure that the carnallite is evenly dispersed and fully reacted. The reaction temperature is 25°C and the reaction time is 2 to 4 hours; Step 13: After the reaction is completed, solid potassium chloride precipitates will appear in the solution, and solid-liquid separation is performed by suction filtration, and the suction filtration pressure is maintained at 0.1-0.3 MPa to obtain a separated mother liquor; Step 14: Wash the separated potassium chloride solid with a small amount of cold water for 2 to 3 times and then mix it with the separated mother liquor to obtain a diluted low-sodium carnallite decomposition mother liquor.

5. The method according to claim 1, characterized in that In step 3, the centrifugation speed is 900 rpm.

6. The method according to claim 1, characterized in that In step 3, the temperature of the freeze-drying treatment is -50°C.

7. A magnesium-based aerogel material of metal M prepared by the preparation method according to any one of claims 1 to 4.

8. The material according to claim 11, characterized in that The microstructure of the magnesium-based aerogel material is a nanowire structure with a diameter of 50 to 200 nm.

9. Use of the magnesium-based aerogel material of metal M according to any one of claims 11 or 12 in the adsorption and removal of metal ions, wherein the metal M is Ni, Ce, Fe, Co, or Cu.

Images