Preparation method of lithium adsorbent with nanofiltration performance

Abstract

The invention discloses a preparation method of a lithium adsorbent with nanofiltration performance, which comprises the following steps: contacting a lithium adsorbent with a water-phase monomer solution, then contacting with an organic-phase solution, carrying out interface composite reaction after contact, forming a layer of nanofiltration membrane on the surface of the lithium adsorbent, and finally obtaining the lithium adsorbent with nanofiltration performance. According to the method, the lithium adsorbent can have nanofiltration performance, the influence of multivalent anions and multivalent cations on lithium ion adsorption of the lithium adsorbent is reduced, and the selectivity of the lithium adsorbent is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of adsorbent preparation, and in particular relates to a method for preparing a lithium adsorbent with nanofiltration performance. Background Art

[0002] Lithium and its compounds are widely used in aviation, medicine, chemical industry, national defense, new energy and other fields, and are known as "an important element that drives the world forward."

[0003] At present, my country's lithium resources are mainly in the form of ions and widely exist in salt lake brine, but its concentration is low. Therefore, it is necessary to use lithium adsorbents to selectively extract lithium from brine. Therefore, preparing lithium adsorbents with high adsorption capacity, high selectivity and strong anti-interference is one of the core key technologies of adsorption lithium extraction technology. Salt lake brine contains a large amount of impurity ions such as sodium, potassium, calcium, magnesium, sulfate, carbonate, etc. Among them, divalent cations such as calcium and magnesium will form competitive adsorption with lithium ions, affecting the selectivity of lithium adsorbents. Sulfate and carbonate are divalent anions. When aluminum-based lithium adsorbents adsorb lithium, these divalent anions will cause aluminum-based lithium adsorbents to be poisoned, resulting in a decrease in adsorption performance and affecting adsorption of lithium. Therefore, reducing the impact of multivalent cations and anions on the adsorption of lithium by adsorbents is particularly important for the development of adsorption lithium extraction technology. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention discloses a method for preparing a lithium adsorbent with nanofiltration performance. The method constructs a nanofiltration layer on the surface of the lithium adsorbent, thereby reducing the competitive adsorption of multivalent cations on the lithium adsorbent, while avoiding poisoning of the aluminum-based lithium adsorbent by multivalent anions, thereby improving the selectivity and stability of the lithium adsorbent.

[0005] In order to achieve the above-mentioned object of the invention, the present invention adopts the following technical solutions:

[0006] A method for preparing a lithium adsorbent with nanofiltration performance, comprising:

[0007] Step 1, dissolving an aqueous phase monomer in water to prepare an aqueous phase monomer solution;

[0008] Step 2, dissolving the oil phase monomer in an organic solution to prepare an oil phase monomer solution;

[0009] Step 3, contacting the lithium adsorbent with the aqueous monomer solution, and then contacting it with the oily monomer solution, after which an interfacial composite reaction occurs to form a nanofiltration film on the surface of the lithium adsorbent, and finally obtaining a lithium adsorbent with nanofiltration performance.

[0010] The aqueous phase monomer is selected from a mixture of one or more of piperazine and its derivatives, polyethyleneimine, metaphenylenediamine and polyols.

[0011] The concentration range in the aqueous monomer solution is 1-20%.

[0012] The oil phase monomer is selected from a mixture of one or more of terephthaloyl chloride, trimesoyl chloride and isophthaloyl chloride.

[0013] The concentration range in the oil phase monomer solution is 0.5-10%.

[0014] The contact time between the aqueous monomer solution and the adsorbent is 5-20 minutes, and the contact time between the oily monomer solution and the adsorbent is 1-5 minutes.

[0015] The organic solvent is selected from a mixture of one or more of cyclohexane, n-hexane, tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, ethanol and methanol.

[0016] The lithium adsorbent is a material that can adsorb lithium ions.

[0017] The lithium adsorbent is one or a mixture of aluminum-based lithium adsorbent, titanium-based lithium adsorbent, and manganese-based lithium adsorbent.

[0018] A process for extracting lithium from brine by adsorption, wherein the above-mentioned adsorbent is used.

[0019] Beneficial Effects

[0020] Nanofiltration membranes have steric hindrance, Donan effect and dielectric effect, and can intercept and separate charged solutes. Since the membrane surface carries ionizable functional groups, charged solutes with the same charge as the membrane surface are more easily repelled due to electrostatic repulsion, while charged solutes with opposite charge to the membrane surface are more likely to enter the membrane pores due to electrostatic attraction. By combining the special selective performance of nanofiltration membranes for charged solutes with lithium adsorbents, a nanofiltration layer is constructed on the surface of the lithium adsorbent. When the lithium adsorbent adsorbs lithium, multivalent cations and anions are intercepted and separated by the nanofiltration layer, reducing the competitive adsorption of multivalent cations on the lithium adsorbent, while avoiding the poisoning of aluminum-based lithium adsorbents by multivalent anions, improving the selectivity and stability of lithium adsorbents, which is of great significance to the development of adsorption and lithium extraction technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a process flow chart for preparing a lithium adsorbent with nanofiltration performance in Example 1 of the present invention;

[0022] Figure 2 is a process flow chart for preparing a lithium adsorbent with nanofiltration performance in Example 2 of the present invention;

[0023] Figure 3 is a process flow chart for preparing a lithium adsorbent with nanofiltration performance in Example 3 of the present invention;

[0024] Figure 4 It is the process flow chart of the patent of this invention. DETAILED DESCRIPTION

[0025] Example 1

[0026] Take 30 grams of piperazine and dissolve it in 300 milliliters of pure water, stir until it is completely dissolved to form an aqueous solution. Take 50 grams of trimesoyl chloride and add it to 1000 milliliters of n-hexane, stir until it is completely dissolved to form an oil solution. Take 20 grams of aluminum lithium adsorbent powder and add it to the aqueous solution for 10 minutes, and then add it to the oil solution for 2 minutes. After the interfacial polymerization reaction occurs, a polyamide nanofiltration layer is formed on the surface of the aluminum lithium adsorbent to obtain an aluminum lithium adsorbent with nanofiltration performance. The preparation process is as follows: Figure 1 Then, 20 grams of aluminum-based lithium adsorbent powder with nanofiltration performance was taken as Example 1, and 20 grams of aluminum-based lithium adsorbent powder without nanofiltration performance was taken as Comparative Example 1, and lithium was adsorbed and extracted in high sulfate brine, and 10 adsorption and desorption cycles were performed respectively. Among them, the ion content in the brine is shown in Table 1. The adsorption capacity of the adsorbents of Example 1 and Comparative Example 1 is shown in Table 2.

[0027] Table 1 Ion content in brine

[0028] g / L lithium sodium Potassium calcium magnesium boron Sulfate brine 0.550 90.650 10.920 40.494 20.396 0.560 50.372

[0029] Table 2 Adsorption capacity of aluminum-based lithium adsorbents of Example 1 and Comparative Example 1

[0030]

[0031] As can be seen from Table 1, the sulfate content of the brine is 50.372 g / L, which is high, and contains impurity ions such as sodium, potassium, calcium and magnesium. As can be seen from Table 2, the aluminum-based lithium adsorbent powder with nanofiltration performance obtained in Example 1 still has a lithium adsorption capacity of 3.19 g / L after 10 cycles of experiments, and has good selectivity for lithium. No divalent impurity ions such as calcium and magnesium are adsorbed. However, the lithium adsorption capacity of the aluminum-based lithium adsorbent powder in Comparative Example 1, which does not use this method, is only 1.10 g / L, and the adsorption capacity is greatly attenuated, and adsorbent poisoning occurs, and more divalent impurity ions such as calcium and magnesium are adsorbed. This shows that the aluminum-based lithium adsorbent powder with nanofiltration performance has good selectivity, avoiding divalent anions from poisoning the aluminum-based adsorbent.

[0032] Example 2

[0033] Take 50 grams of piperazine and dissolve it in 500 milliliters of pure water, stir until it is completely dissolved to form an aqueous solution. Take 100 grams of trimesoyl chloride and add it to 2000 milliliters of n-hexane, stir until it is completely dissolved to form an oil solution. Take 25 grams of manganese lithium adsorbent powder and add it to the aqueous solution, and then add it to the oil solution. After the interfacial polymerization reaction occurs, a polyamide nanofiltration layer is formed on the surface of the manganese lithium adsorbent to obtain an aluminum lithium adsorbent with nanofiltration performance. The preparation process is as follows: Figure 2 Then, 25 grams of manganese-based lithium adsorbent powder with nanofiltration performance was taken as Example 2, and 25 grams of manganese-based lithium adsorbent powder without nanofiltration performance was taken as Comparative Example 2, and lithium was adsorbed and extracted in brine for 10 adsorption and desorption cycles. The ion content in the brine is shown in Table 3. The adsorption capacity of the adsorbents in Example 2 and Comparative Example 2 is shown in Table 4.

[0034] Table 3 Ion content in brine

[0035] mg / L lithium sodium Potassium calcium magnesium boron brine 261.0 12710.0 1917.0 900.6 1916.8 675.1

[0036] Table 4 Adsorption capacity of manganese-based lithium adsorbents in Example 2 and Comparative Example 2

[0037]

[0038] As can be seen from Table 3, the calcium ion content of the brine is 900.6 mg / L, the magnesium ion content is 1916.8 mg / L, it contains a large amount of divalent cations, and contains a large amount of sodium and potassium ions. As can be seen from Table 4, the manganese-based lithium adsorbent powder with nanofiltration performance obtained in Example 2 still has a lithium adsorption capacity of 7.587 g / L after 10 cycles of experiments, and has good selectivity for lithium. Divalent hetero ions such as calcium and magnesium are not adsorbed, while the manganese-based lithium adsorbent powder in Comparative Example 2, which does not use this method, has a lithium adsorption capacity of only 6.853 g / L, and the adsorption capacity has a large attenuation, and more divalent hetero ions such as calcium and magnesium are adsorbed. This shows that the manganese-based lithium adsorbent powder with nanofiltration performance has good selectivity.

[0039] Example 3

[0040] Take 60 grams of piperazine and dissolve it in 600 milliliters of pure water, stir until it is completely dissolved to form an aqueous solution. Take 200 grams of trimesoyl chloride and add it to 3000 milliliters of n-hexane, stir until it is completely dissolved to form an oil solution. Take 30 grams of titanium lithium adsorbent powder and add it to the aqueous solution, and then add it to the oil solution. After the interfacial polymerization reaction occurs, a polyamide nanofiltration layer is formed on the surface of the titanium lithium adsorbent to obtain a titanium lithium adsorbent with nanofiltration performance. The preparation process is as follows: Figure 3Then, 30 grams of titanium-based lithium adsorbent powder with nanofiltration performance was taken as Example 3, and 30 grams of titanium-based lithium adsorbent powder without nanofiltration performance was taken as Comparative Example 3, and lithium was adsorbed and extracted in brine for 10 adsorption and desorption cycles. The ion content in the brine is shown in Table 5. The adsorption capacity of the adsorbents of Example 3 and Comparative Example 3 is shown in Table 6.

[0041] Table 5 Ion content in brine

[0042] mg / L lithium sodium Potassium calcium magnesium boron brine 192 61110 15810 859 1093 192

[0043] Table 6 Adsorption capacity of titanium-based lithium adsorbents in Example 3 and Comparative Example 3

[0044]

[0045] As can be seen from Table 5, the calcium ion content of the brine is 859 mg / L, the magnesium ion content is 1093 mg / L, it contains a large amount of divalent cations, and contains a large amount of sodium and potassium ions. As can be seen from Table 6, the titanium-based lithium adsorbent powder with nanofiltration performance obtained in Example 3 still has a lithium adsorption capacity of 5.976 g / L after 10 cycles of experiments, and has good selectivity for lithium. Divalent hetero ions such as calcium and magnesium are not adsorbed, while the lithium adsorption capacity of the titanium-based lithium adsorbent powder in Comparative Example 3, which does not use this method, is only 4.758 g / L, and the adsorption capacity has a large attenuation, and more divalent hetero ions such as calcium and magnesium are adsorbed. This shows that the titanium-based lithium adsorbent powder with nanofiltration performance has good selectivity.

Claims

1. A method for preparing a lithium adsorbent with nanofiltration performance, characterized in that: The steps include: Step 1, dissolving an aqueous phase monomer in water to prepare an aqueous phase monomer solution; Step 2, dissolving the oil phase monomer in an organic solution to prepare an oil phase monomer solution; Step 3, contacting the lithium adsorbent with the aqueous monomer solution, and then contacting it with the oily monomer solution, after which an interfacial composite reaction occurs to form a nanofiltration film on the surface of the lithium adsorbent, and finally obtaining a lithium adsorbent with nanofiltration performance.

2. The method for preparing a lithium adsorbent with nanofiltration performance according to claim 1, characterized in that: The aqueous phase monomer is selected from a mixture of one or more of piperazine and its derivatives, polyethyleneimine, metaphenylenediamine and polyols.

3. The method for preparing a lithium adsorbent with nanofiltration performance according to claim 1, characterized in that: The concentration range in the aqueous monomer solution is 1-20%.

4. The method for preparing a lithium adsorbent with nanofiltration performance according to claim 1, characterized in that: The oil phase monomer is selected from a mixture of one or more of terephthaloyl chloride, trimesoyl chloride and isophthaloyl chloride.

5. The method for preparing a lithium adsorbent with nanofiltration performance according to claim 1, characterized in that: The concentration range in the oil phase monomer solution is 0.5-10%.

6. The method for preparing a lithium adsorbent with nanofiltration performance according to claim 1, characterized in that: The contact time between the aqueous monomer solution and the adsorbent is 5-20 minutes, and the contact time between the oily monomer solution and the adsorbent is 1-5 minutes.

7. The method for preparing a lithium adsorbent with nanofiltration performance according to claim 1, characterized in that: The organic solvent is selected from a mixture of one or more of cyclohexane, n-hexane, tetrahydrofuran, dimethyl sulfoxide, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, ethanol and methanol.

8. The method for preparing a lithium adsorbent with nanofiltration performance according to claim 1, characterized in that: The lithium adsorbent is a material that can adsorb lithium ions.

9. The method for preparing a lithium adsorbent with nanofiltration performance according to claim 1, characterized in that: The lithium adsorbent is one or a mixture of aluminum-based lithium adsorbent, titanium-based lithium adsorbent, and manganese-based lithium adsorbent.

10. A process for extracting lithium from brine by adsorption, wherein the adsorbent obtained by the preparation method according to any one of claims 1 to 9 is used.

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