Melamine-based adsorbent material, preparation method and application thereof

Abstract

The present application relates to a kind of adsorbing material based on melamine and its preparation method and application, belong to nonferrous metallurgy technical field, solve the selective poor of adsorbing material in prior art to lithium in low concentration complex system of lithium-containing wastewater, low adsorption capacity and other problems.The adsorbing material based on melamine described in the present application is the covalent organic framework adsorbing material constructed with melamine and benzo 12-crown-4-ether as skeleton, the adsorbing material has hexagonal structure, good stability;And simple synthesis method, product has high porosity, low density and high specific surface area and other advantages, can realize the super high capacity adsorption of lithium.The adsorbing material based on melamine described is applied to selective lithium extraction in lithium-containing wastewater, can realize the efficient target recognition and super high capacity adsorption of lithium in low concentration system.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of non-ferrous metallurgy, and particularly relates to a melamine-based adsorption material and a preparation method and application thereof. BACKGROUND

[0002] Lithium and its compounds are widely used in new energy, metallurgy, aerospace, military and defense, and glass manufacturing due to their excellent physical and chemical properties, and are considered as "energy metals driving the progress of the world". Due to the importance and scarcity of lithium resources, developed countries and regions such as the United States, the European Union and Japan have defined it as "key metal" and "strategic metal".

[0003] At present, the most important use of lithium is in the new energy industry. Lithium-ion batteries are widely used in power batteries of new energy vehicles due to their excellent performances such as large specific capacity, high energy density and low self-discharge rate. However, the service life of lithium-ion batteries is usually only 5-8 years, and the battery capacity decreases significantly after 500-1000 cycles, becoming a scrap battery. The lithium content in the scrap lithium-ion battery is as high as 5-7%, which is much higher than that of natural ore, and has become the most important secondary lithium resource at present. Therefore, it is of great significance to develop the recycling of lithium from scrap lithium-ion batteries for the sustainable development of the new energy industry.

[0004] Lithium-containing wastewater is generated in the recycling process of scrap lithium-ion batteries. The composition of the wastewater is complex, the lithium content is low, and the impurity content is high, which makes it difficult to effectively and deeply recover lithium. Therefore, it has become a research hotspot to develop adsorption materials with high selectivity and high capacity for lithium.

[0005] The Chinese patent with the application number 202111345745.8 discloses a preparation method of a high-adsorption-capacity particulate titanium-based lithium ion sieve adsorbent. First, a titanium-based lithium ion sieve precursor powder is prepared using a lithium source, titanium dioxide, a dispersing agent, a pore-forming agent, and the like as main raw materials. Then, a particulate titanium-based lithium ion sieve adsorbent is further synthesized based on the precursor powder. The product has high porosity and can exhibit good suspension and adsorption-desorption performance during the adsorption process. The Chinese patent with the application number 202111046666.7 discloses a lithium extraction adsorbent and a preparation method thereof. A suspension aqueous solution of mixed aluminum hydroxide and lithium chloride is reacted with strong acid wastewater, and a precipitating agent is further added to precipitate and solidify the aluminum-lithium ions under the action of co-precipitation, thereby obtaining a lithium adsorbent and achieving the preparation of valuable adsorbent materials while treating wastewater. The Chinese patent with the application number 202211444118.4 discloses a preparation method of a high-adsorption-capacity porous particulate lithium adsorbent. A cross-linked interpenetrating network structure of polyionic liquid containing quaternary amine groups is used as a binder, which makes the lithium adsorbent particles highly hydrophilic. Through multiple cross-linking actions, the mechanical strength of the adsorbent material is effectively improved, and the dissolution loss and shedding of the adsorbent powder during the recycling process are reduced. The above adsorbent materials can exhibit certain adsorption performance for lithium, but for low-concentration complex systems such as lithium-containing wastewater, it is difficult to achieve ideal recovery results. SUMMARY

[0006] In view of the above analysis, the present application aims to provide a melamine-based adsorbent material and its preparation method and application, to solve one of the problems in the prior art, such as complex composition of recovered lithium-containing wastewater, low lithium content, high impurity concentration, poor selectivity of adsorbent material for lithium, and low adsorption capacity.

[0007] In a first aspect, the present application provides a preparation method of a melamine-based adsorbent material, comprising the following steps:

[0008] (1) mixing benzene-12-crown-4-ether with a first catalyst, adding an organic solvent for dissolution, cooling, adding liquid bromine under stirring, warming to room temperature for reaction, removing unreacted liquid bromine, purifying, drying, and evaporating to obtain a first product;

[0009] (2) mixing the first product, 4-formylphenylboronic acid, potassium carbonate, and a second catalyst, adding toluene and water, and stirring under an inert atmosphere for reaction, purifying, drying, and evaporating to obtain a second product;

[0010] (3) mixing the second product and melamine, then adding o-dichlorobenzene, n-butanol, and acetic acid solution, mixing uniformly, and performing reaction under vacuum to obtain a crude product, which is washed, centrifuged, and dried to obtain the melamine-based adsorbent material.

[0011] Further, in step (1), the molar ratio of benzo 12-crown-4-ether to the first catalyst is 1:6-1:2, preferably, the first catalyst is iron powder, more preferably, the organic solvent is dichloromethane.

[0012] Further, in step (1), the stirring speed is 300-500 rpm, and the reaction time is 2-6 h.

[0013] Further, in step (2), the molar ratio of the first product to 4-formylphenylboronic acid is 1:5-1:10, the molar ratio of the first product to potassium carbonate is 1:8-1:12, and the molar ratio of the first product to the second catalyst is 1:1-3:1, preferably, the second catalyst is Pd(PPh3)4.

[0014] Further, in step (2), the volume ratio of toluene to water is 2:1-6:1, preferably, the inert atmosphere is one or more of nitrogen, argon, and helium.

[0015] Further, in step (2), the reaction temperature is 100-120℃, the reaction time is 3-48 h, and the stirring speed is 300-500 rpm.

[0016] Further, in step (3), the molar ratio of melamine to the second product is 1:1-1:5, the volume ratio of o-dichlorobenzene to n-butanol is 1:2-1:6, and the volume ratio of o-dichlorobenzene to acetic acid solution is 1:1-1:5.

[0017] Further, in step (3), the vacuum degree is 0.05-0.2 Pa, the reaction temperature is 110-150℃, and the reaction time is 3-48 h.

[0018] In a second aspect, the application provides a melamine-based adsorbent material prepared by the above method.

[0019] In a third aspect, the application provides an application of the melamine-based adsorbent material in deep lithium extraction from lithium-containing wastewater.

[0020] Compared with the prior art, the application can achieve at least one of the following beneficial effects:

[0021] (1) The melamine-based adsorbent material is a covalent organic framework adsorbent material constructed with melamine and benzo 12-crown-4-ether as a skeleton, has a hexagonal structure, and has good stability; the synthesis method is simple, the adsorbent material has high porosity, low density, and high specific surface area, and can realize ultra-high capacity adsorption of lithium with an adsorption capacity of more than 81 mg / g;

[0022] (2) The melamine-based adsorbent material contains rich melamine units, wherein the N atom with strong electron-donating ability can realize selective and specific recognition of lithium in the "low lithium and high impurity" wastewater system through the unique "lithium bond" effect between lithium ions, and the lithium ions are adsorbed into the pores of the covalent organic framework adsorbent material to realize deep selective separation and extraction of lithium;

[0023] (3) The melamine-based adsorbent material contains benzene 12-crown-4 ether units, the crown ether ring cavity is highly matched with the size of lithium ions, and the lithium ions selectively recognized by the π electron environment and N atom can be efficiently nested into the crown ether ring to realize sufficient fixation of lithium ions, thereby improving the selectivity and adsorption efficiency of the adsorbent material for lithium.

[0024] (4) The melamine-based adsorbent material contains rich benzene ring units, which greatly improves the structural rigidity of the adsorbent material, and also fills the pores of the adsorbent material with π electron cloud environment, thereby synergistically enhancing the selective recognition and adsorption process of lithium ions.

[0025] In the present application, the above technical solutions can also be combined with each other to realize more preferred combination schemes. Other features and advantages of the present application will be described in the subsequent specification, and some advantages will become apparent from the specification or be understood by implementing the present application. The purposes and other advantages of the present application can be achieved and obtained from the contents specifically pointed out in the specification. DETAILED DESCRIPTION

[0026] In one specific embodiment of the present application, a preparation method of a melamine-based adsorbent material is disclosed, which comprises the following steps:

[0027] (1) The benzene 12-crown-4 ether is mixed with a first catalyst, dissolved in an organic solvent, cooled, and then excess liquid bromine is added under stirring, and the reaction is carried out by warming to room temperature. The unreacted liquid bromine is removed, purified, dried, and evaporated to obtain a first product;

[0028] (2) The first product, 4-formylphenylboronic acid, potassium carbonate and a second catalyst are mixed, toluene and water are added, and the reaction is carried out under stirring in an inert atmosphere. The product is purified, dried, and evaporated to obtain a second product;

[0029] (3) The second product and melamine are mixed, and then o-dichlorobenzene, n-butanol and acetic acid solution are added, mixed uniformly, and the reaction is carried out under vacuum to obtain a crude product. The product is washed, centrifuged, and dried to obtain the melamine-based adsorbent material.

[0030] Compared with the prior art, the melamine-based adsorbent material of the present application is a covalent organic framework adsorbent material constructed with melamine and benzene 12-crown-4 ether as a skeleton, has a hexagonal structure, good stability, a simple synthesis method, and advantages such as high porosity, low density and high specific surface area, and can realize super-high capacity adsorption of lithium with an adsorption capacity of more than 81 mg / g.

[0031] In one specific embodiment, in step (1), the molar ratio of benzene 12-crown-4 ether to the first catalyst is 1:6 to 1:2, for example, the molar ratio is 1:6, 1:5, 1:4, 1:3, 1:2.

[0032] In one specific embodiment, in step (1), the first catalyst is iron powder.

[0033] In one specific embodiment, in step (1), the organic solvent is dichloromethane.

[0034] In one specific embodiment, in step (1), the stirring speed is 300 to 500 rpm, for example, the speed is 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm, and the reaction time is 2 to 6 h, for example, the reaction time is 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h.

[0035] Specifically, in step (1), cooling to 0℃ is performed, and the reaction is performed for 2 to 6 h, for example, the reaction is performed for 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h.

[0036] It should be noted that in step (1), saturated sodium sulfite solution is added to remove unreacted liquid bromine, and water / dichloromethane is used for repeated extraction and purification 3 to 5 times, the organic phase is dehydrated and dried, the drying agent is one or more of anhydrous sodium sulfate, anhydrous potassium sulfate or anhydrous magnesium sulfate, the organic solvent is removed by evaporation, and the evaporation temperature is 40 to 60℃, for example, the evaporation temperature is 40℃, 45℃, 50℃, 55℃, 60℃.

[0037] In one specific embodiment, in step (2), the molar ratio of the first product to 4-formylphenylboronic acid is 1:5 to 1:10, for example, the molar ratio is 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, the molar ratio of the first product to potassium carbonate is 1:8 to 1:12, for example, the molar ratio is 1:8, 1:9, 1:10, 1:11, 1:12, and the molar ratio of the first product to the second catalyst is 1:1 to 3:1, for example, the molar ratio is 1:1, 1.5:1, 2:1, 2.5:1, 3:1.

[0038] In one embodiment, the second catalyst in step (2) is Pd(PPh3)4.

[0039] In one embodiment, the volume ratio of toluene to water in step (2) is 2:1 to 6:1, for example, 2:1, 3:1, 4:1, 5:1, or 6:1.

[0040] Preferably, the inert atmosphere is one or more of nitrogen, argon, and helium.

[0041] In one embodiment, the temperature in step (2) is 100 to 120 °C, for example, 100 °C, 105 °C, 110 °C, 115 °C, or 120 °C, the reaction time is 3 to 48 h, for example, 3 h, 6 h, 12 h, 18 h, 24 h, 30 h, 36 h, 42 h, or 48 h, and the stirring speed is 300 to 500 rpm, for example, 300 rpm, 350 rpm, 400 rpm, 450 rpm, or 500 rpm.

[0042] It should be noted that in step (2), the purification by repeated extraction with ethyl acetate / water is performed 3 to 5 times, the organic phase is dehydrated and dried, the drying agent is one or more of anhydrous sodium sulfate, anhydrous potassium sulfate, or anhydrous magnesium sulfate, and the temperature for evaporation to remove the organic solvent is 4 to 60 °C, for example, 4 °C, 10 °C, 15 °C, 20 °C, 25 °C, 30 °C, 35 °C, 40 °C, 45 °C, 50 °C, 55 °C, or 60 °C.

[0043] In one embodiment, in step (3), the molar volume ratio of the second product to the mixture of o-dichlorobenzene, n-butanol, and acetic acid is 1 mol:50 mL.

[0044] In one embodiment, in step (3), the molar ratio of melamine to the second product is 1:1 to 1:5, for example, 1:1, 1:2, 1:3, 1:4, or 1:5, the volume ratio of o-dichlorobenzene to n-butanol is 1:2 to 1:6, for example, 1:2, 1:3, 1:4, 1:5, or 1:6, and the volume ratio of o-dichlorobenzene to acetic acid solution is 1:1 to 1:5, for example, 1:1, 1:2, 1:3, 1:4, or 1:5.

[0045] It should be noted that in step (3), the concentration of acetic acid in the acetic acid solution is 6 mol / L.

[0046] In one specific embodiment, in step (3), the vacuum degree is 0.05-0.2 Pa, for example, the vacuum degree is 0.05 Pa, 0.07 Pa, 0.09 Pa, 0.11 Pa, 0.13 Pa, 0.15 Pa, 0.17 Pa, 0.19 Pa, 0.2 Pa, the reaction temperature is 110-150°C, for example, the temperature is 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, and the reaction time is 3-48 h. For example, the time is 3 h, 6 h, 12 h, 18 h, 24 h, 30 h, 36 h, 42 h, 48 h.

[0047] It should be noted that in step (3), the crude product is washed with DMF, THF and acetone in sequence, centrifuged and separated, and dried in a vacuum drying oven at a temperature of 110-150°C, for example, the temperature is 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, 145°C, 150°C, and dried for 3-12 h, for example, dried for 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, 11 h, 12 h.

[0048] Another specific embodiment of the present application discloses a melamine-based adsorbent material prepared by the above method.

[0049] Another specific embodiment of the present application discloses the application of the above-mentioned melamine-based adsorbent material in deep lithium extraction from lithium-containing wastewater. The adsorbent material is added to the lithium-containing wastewater, and high-efficiency targeted recognition and ultra-high capacity adsorption of lithium can be achieved under constant temperature reaction with stirring.

[0050] It should be noted that in the lithium-containing wastewater, the addition amount of the melamine-based adsorbent material is 0.2-5 g / L, for example, the addition amount is 0.2 g / L, 0.5 g / L, 1.0 g / L, 1.5 g / L, 2.0 g / L, 2.5 g / L, 3.0 g / L, 3.5 g / L, 4.0 g / L, 4.5 g / L, 5 g / L, the constant temperature reaction temperature is 20-90°C, for example, the temperature is 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, the reaction time is 0.5-6 h, for example, the reaction time is 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h, 6 h, and the stirring speed is 300-500 rpm, for example, the stirring speed is 300 rpm, 350 rpm, 400 rpm, 450 rpm, 500 rpm.

[0051] Specifically, the main component lithium in the lithium-containing wastewater has a concentration of 100-5000 mg / L, the sodium has a concentration of 0.5-50 g / L, the pH is 0-12, and the lithium adsorption capacity is above 80 mg / g, for example, 80 mg / g, 82 mg / g, 84 mg / g, 86 mg / g, 88 mg / g, 90 mg / g, 92 mg / g, or 94 mg / g.

[0052] The melamine-based adsorption material contains rich melamine units, wherein the N atom with strong electron-donating ability can realize selective and specific recognition of lithium in a “low-lithium and high-impurity” wastewater system through the unique “lithium bond” effect between lithium ions, and the lithium ions are adsorbed into the pores of the covalent organic framework adsorption material to realize deep selective separation and extraction of lithium.

[0053] The melamine-based adsorption material contains benzene 12-crown-4-ether units, the cavity of the crown ether ring is highly matched with the size of lithium ions, the lithium ions selectively recognized by the π-electron environment and the N atom can be efficiently nested in the crown ether ring to realize sufficient fixation of the lithium ions, and this is beneficial to improving the selectivity and adsorption efficiency of the adsorption material for lithium.

[0054] The melamine-based adsorption material contains rich benzene ring units, which greatly improves the structural rigidity of the adsorption material and also makes the pores of the adsorption material full of π-electron cloud environment, thereby synergistically strengthening the selective recognition and adsorption process of the adsorption material for lithium ions. The melamine-based adsorption material can be applied to selective lithium extraction from lithium-containing wastewater to realize efficient and targeted recognition and ultra-high capacity adsorption of lithium in a low-concentration system.

[0055] The technical solutions of the present application are further explained and described below in combination with specific examples.

[0056] Example 1

[0057] The preparation method of the melamine-based adsorption material of the present application comprises the following steps:

[0058] (1) Benzene 12-crown-4-ether and iron powder are mixed in a flask according to a molar ratio of 1:6, dichloromethane is added to fully dissolve the benzene 12-crown-4-ether, then the reaction system is cooled to 0℃ in an ice bath, and excess liquid bromine is slowly added to the reaction system under stirring at a rotation speed of 300 rpm and continuously reacted for 6 h, and then the reaction is continued for 6 h after the temperature is raised to room temperature. After the reaction is completed, saturated sodium sulfite solution is added to the system to remove unreacted liquid bromine, and then the mixture is repeatedly extracted and purified with water / dichloromethane for 3 times, anhydrous sodium sulfate is used to dehydrate and dry the organic phase, and the organic solvent is evaporated at 40℃ to obtain a first product.

[0059] (2) the first product, 4-formylphenylboronic acid, potassium carbonate and Pd(PPh3)4 are mixed and added into a Schlenck tube, then degassed toluene and water are added into the system, wherein the molar ratio of the first product to 4-formylphenylboronic acid is 1:5, the molar ratio of the first product to potassium carbonate is 1:8, the molar ratio of the first product to Pd(PPh3)4 is 1:1, and the volume ratio of toluene to water is 2:1; after degassing by freeze-pump-thaw cycle, the reaction is carried out at 100°C under nitrogen atmosphere for 48 h with stirring at a speed of 300 rpm; after the reaction, the mixture is repeatedly extracted and purified with ethyl acetate / water for 3 times, the organic phase is dehydrated and dried with anhydrous sodium sulfate, and the organic solvent is removed by evaporation at 40°C to obtain a second product;

[0060] (3) the second product and melamine are mixed and added into a glass tube with one end sealed, then o-dichlorobenzene, n-butanol and 6 mol / L acetic acid solution are added, wherein the molar ratio of melamine to the second product is 1:1, the volume ratio of o-dichlorobenzene to n-butanol is 1:2, the volume ratio of o-dichlorobenzene to acetic acid solution is 1:1, and the molar volume ratio of the second product to the mixed solution of o-dichlorobenzene, n-butanol and acetic acid is 1 mol:50 mL; after mixing uniformly, the glass tube is quickly frozen in a liquid nitrogen bath, vacuum packaging is performed by using a vacuum packaging machine to make the pressure 0.05 Pa, then a high-temperature flame gun is used for melting and sealing, and the sealed glass tube is placed in an oven for reaction at 110°C for 48 h to obtain a crude product; the obtained crude product is washed with DMF, THF and acetone in sequence, centrifuged and separated, and dried at 110°C for 12 h to obtain the melamine-based adsorbent material.

[0061] Example 2

[0062] The preparation method of the melamine-based adsorbent material in this embodiment comprises the following steps:

[0063] (1) benzene-12-crown-4-ether and iron powder are mixed and added into a flask according to a molar ratio of 1:2, dichloromethane is added to fully dissolve the benzene-12-crown-4-ether, then the reaction system is cooled to 0°C in an ice bath, excess liquid bromine is slowly added into the reaction system under stirring at a speed of 500 rpm and the reaction is continued for 2 h, the temperature is then increased to room temperature and the reaction is continued for 2 h, after the reaction, saturated sodium sulfite solution is added into the system to remove the unreacted liquid bromine, then the mixture is repeatedly extracted and purified with water / dichloromethane for 5 times, the organic phase is dehydrated and dried with anhydrous sodium sulfate, and the organic solvent is removed by evaporation at 60°C to obtain a first product;

[0064] (2) the first product, 4-formylphenylboronic acid, potassium carbonate and Pd(PPh3)4 are mixed and added into a Schlenck tube, then degassed toluene and water are added into the system, wherein the molar ratio of the first product to 4-formylphenylboronic acid is 1:10, the molar ratio of the first product to potassium carbonate is 1:12, the molar ratio of the first product to Pd(PPh3)4 is 3:1, and the volume ratio of toluene to water is 6:1; after degassing by freeze-pump-thaw cycle, the reaction is carried out under argon atmosphere at 120℃ for 3h with stirring at a speed of 500rpm; after the reaction, the mixture is repeatedly extracted and purified with ethyl acetate / water for 5 times, the organic phase is dehydrated and dried with anhydrous potassium sulfate, and the organic solvent is removed by evaporation at 60℃ to obtain a second product;

[0065] (3) the second product and melamine are mixed and added into a glass tube with one end sealed, then o-dichlorobenzene, n-butanol and 6mol / L acetic acid solution are added, wherein the molar ratio of melamine to the second product is 1:5, the volume ratio of o-dichlorobenzene to n-butanol is 1:6, the volume ratio of o-dichlorobenzene to acetic acid solution is 1:5, and the molar volume ratio of the second product to the mixed solution of o-dichlorobenzene, n-butanol and acetic acid is 1mol:50mL; after mixing, the glass tube is quickly frozen in a liquid nitrogen bath, vacuum sealed by a vacuum sealing machine to a pressure of 0.2Pa, then melted and sealed by a high-temperature flame gun, and the sealed glass tube is placed in an oven for reaction at 150℃ for 3h to obtain a crude product; the obtained crude product is sequentially washed with DMF, THF and acetone, centrifuged and separated, and dried at 150℃ for 3h to obtain the melamine-based adsorbent material.

[0066] Example 3

[0067] The preparation method of the melamine-based adsorbent material in this embodiment comprises the following steps:

[0068] (1) benzene-12-crown-4-ether and iron powder are mixed and added into a flask according to a molar ratio of 1:5, dichloromethane is added to fully dissolve the benzene-12-crown-4-ether, then the reaction system is cooled to 0℃ in an ice bath, excess liquid bromine is slowly added into the reaction system under stirring at a speed of 350rpm and the reaction is continued for 3h, the temperature is then increased to room temperature and the reaction is continued for 3h, after the reaction, saturated sodium sulfite solution is added into the system to remove the unreacted liquid bromine, then the mixture is repeatedly extracted and purified with water / dichloromethane for 4 times, the organic phase is dehydrated and dried with anhydrous magnesium sulfate, and the organic solvent is removed by evaporation at 45℃ to obtain a first product;

[0069] (2) the first product, 4-formylphenylboronic acid, potassium carbonate and Pd(PPh3)4 are mixed and added into a Schlenck tube, then degassed toluene and water are added into the system, wherein the molar ratio of the first product to 4-formylphenylboronic acid is 1:6, the molar ratio of the first product to potassium carbonate is 1:9, the molar ratio of the first product to Pd(PPh3)4 is 1.5:1, and the volume ratio of toluene to water is 3:1; after degassing by freeze-pump-thaw cycle, the reaction is carried out at 105℃ under a helium atmosphere for 12h with a stirring speed of 350rpm; after the reaction, the mixture is repeatedly extracted and purified with ethyl acetate / water for 4 times, the organic phase is dehydrated and dried with anhydrous magnesium sulfate, and the organic solvent is removed by evaporation at 45℃ to obtain a second product;

[0070] (3) the second product and melamine are mixed and added into a glass tube with one end sealed, then o-dichlorobenzene, n-butanol and 6mol / L acetic acid solution are added, wherein the molar ratio of melamine to the second product is 1:2, the volume ratio of o-dichlorobenzene to n-butanol is 1:3, the volume ratio of o-dichlorobenzene to acetic acid solution is 1:2, and the molar volume ratio of the second product to the mixed solution of o-dichlorobenzene, n-butanol and acetic acid is 1mol:50mL; after mixing uniformly, the glass tube is quickly frozen in a liquid nitrogen bath, vacuum packaging is performed by using a vacuum packaging machine until the pressure is 0.1Pa, then a high-temperature flame gun is used for melting and sealing, and the sealed glass tube is placed in an oven for reaction at 120℃ for 12h to obtain a crude product; the obtained crude product is washed with DMF, THF and acetone in sequence, centrifuged and separated, and dried at 120℃ for 5h to obtain the melamine-based adsorbent material.

[0071] Example 4

[0072] The preparation method of the melamine-based adsorbent material in this embodiment comprises the following steps:

[0073] (1) benzene-12-crown-4-ether and iron powder are mixed and added into a flask according to a molar ratio of 1:4, dichloromethane is added to fully dissolve the benzene-12-crown-4-ether, then the reaction system is cooled to 0℃ in an ice bath, excess liquid bromine is slowly added into the reaction system under stirring at a speed of 400rpm and the reaction is continued for 4h, the temperature is then increased to room temperature and the reaction is continued for 4h, after the reaction, saturated sodium sulfite solution is added into the system to remove the unreacted liquid bromine, then the mixture is repeatedly extracted and purified with water / dichloromethane for 5 times, the organic phase is dehydrated and dried with anhydrous sodium sulfate, and the organic solvent is removed by evaporation at 50℃ to obtain a first product;

[0074] (2) the first product, 4-formylphenylboronic acid, potassium carbonate and Pd(PPh3)4 are mixed and added into a Schlenck tube, then degassed toluene and water are added into the system, wherein the molar ratio of the first product to 4-formylphenylboronic acid is 1:7, the molar ratio of the first product to potassium carbonate is 1:10, the molar ratio of the first product to Pd(PPh3)4 is 2:1, and the volume ratio of toluene to water is 4:1; after degassing by freeze-pump-thaw cycle, the reaction is carried out at 110°C under nitrogen atmosphere for 15h with stirring at a speed of 400rpm; after the reaction, the mixture is repeatedly extracted and purified with ethyl acetate / water for 5 times, the organic phase is dehydrated and dried with anhydrous sodium sulfate, and the organic solvent is removed by evaporation at 50°C to obtain the second product;

[0075] (3) the second product and melamine are mixed and added into a glass tube with one end sealed, then o-dichlorobenzene, n-butanol and 6mol / L acetic acid solution are added, wherein the molar ratio of melamine to the second product is 1:3, the volume ratio of o-dichlorobenzene to n-butanol is 1:4, the volume ratio of o-dichlorobenzene to acetic acid solution is 1:3, and the molar volume ratio of the second product to the mixed solution of o-dichlorobenzene, n-butanol and acetic acid is 1mol:50mL; after mixing uniformly, the glass tube is quickly frozen in a liquid nitrogen bath, vacuum packaging is performed by using a vacuum packaging machine to make the pressure 0.15Pa, then a high-temperature flame gun is used for melting and sealing, and the sealed glass tube is placed in an oven for reaction at 130°C for 15h to obtain a crude product; the obtained crude product is washed with DMF, THF and acetone in sequence, centrifuged and separated, and dried at 130°C for 8h to obtain the melamine-based adsorbent material.

[0076] Example 5

[0077] The preparation method of the melamine-based adsorbent material in this embodiment comprises the following steps:

[0078] (1) benzene-12-crown-4-ether and iron powder are mixed and added into a flask according to a molar ratio of 1:3, dichloromethane is added to fully dissolve the benzene-12-crown-4-ether, then the reaction system is cooled to 0°C in an ice bath, excess liquid bromine is slowly added into the reaction system under stirring at a speed of 450rpm and the reaction is continued for 5h, the temperature is then increased to room temperature and the reaction is continued for 5h, after the reaction, saturated sodium sulfite solution is added into the system to remove the unreacted liquid bromine, then the mixture is repeatedly extracted and purified with water / dichloromethane for 3 times, the organic phase is dehydrated and dried with anhydrous magnesium sulfate, and the organic solvent is removed by evaporation at 55°C to obtain the first product;

[0079] (2) The first product, 4-formylphenylboronic acid, potassium carbonate and Pd(PPh3)4 are mixed and added to a Schlenck tube, and then degassed toluene and water are added to the system, wherein the molar ratio of the first product to 4-formylphenylboronic acid is 1:6, the molar ratio of the first product to potassium carbonate is 1:11, the molar ratio of the first product to Pd(PPh3)4 is 2.5:1, and the volume ratio of toluene to water is 5:1; after degassing by freeze-pump-thaw cycle, the reaction is carried out under argon atmosphere at 115°C for 20h with stirring at a speed of 450rpm, and after the reaction is completed, the mixture is repeatedly extracted and purified with ethyl acetate / water for 3 times, the organic phase is dehydrated and dried with anhydrous sodium sulfate, and the organic solvent is removed by evaporation at 55°C to obtain the second product;

[0080] (3) The second product and melamine are mixed and added to a glass tube with one end sealed, and then o-dichlorobenzene, n-butanol and 6mol / L acetic acid solution are added, wherein the molar ratio of melamine to the second product is 1:4, the volume ratio of o-dichlorobenzene to n-butanol is 1:5, the volume ratio of o-dichlorobenzene to acetic acid solution is 1:14, and the molar volume ratio of the second product to the mixed solution of o-dichlorobenzene, n-butanol and acetic acid is 1mol:50mL; after mixing uniformly, the glass tube is quickly frozen in a liquid nitrogen bath, vacuum packaging is performed by using a vacuum packaging machine to make the pressure 0.1Pa, and then the glass tube is sealed by using a high-temperature flame gun, and the sealed glass tube is placed in an oven for reaction at 140°C for 20h to obtain a crude product; the obtained crude product is washed with DMF, THF and acetone in sequence, centrifuged and separated, and dried at 140°C for 10h to obtain the melamine-based adsorption material.

[0081] Test Example 1

[0082] The melamine-based adsorption material prepared in Examples 1-5 is subjected to adsorption test, and in this test example, simulated lithium-containing wastewater is used for test. The main components in the simulated lithium-containing wastewater are shown in Table 1.

[0083] Table 1

[0084] pH Li + ]]> Na + ]] SO4 2- ]] 11.5 500 mg / L 5000 mg / L 13871 mg / L

[0085] The adsorption test is as follows: the same mass of the melamine-based adsorption material prepared in Examples 1-5, benzene-12-crown-4 ether and melamine is respectively added to the same volume of simulated lithium-containing wastewater, and the addition amount of each adsorption material is 2g / L, and after reaction at a speed of 400rpm for 3h at a temperature of 20°C, the content of the main components in the simulated lithium-containing wastewater after adsorption is detected, and the results are shown in Table 2.

[0086] Table 2

[0087]

[0088] From the data in Table 2, when the adsorption material prepared by the present application is used to adsorb lithium from simulated lithium-containing wastewater, the lithium adsorption capacity is all above 80 mg / g, the adsorption material of the present application exhibits ultra-high lithium adsorption capacity, and basically does not adsorb sodium. In addition, when melamine and benzo 12-crown-4 ether are used alone to treat lithium-containing wastewater, the lithium adsorption capacity is relatively low.

[0089] Test Example 2

[0090] In this test example, the melamine-based adsorption material prepared in Example 1 is used for adsorption test, and the specific test is the same as that in Test Example 1, only the addition amount of the melamine-based adsorption material is changed, the influence of the addition amount of the adsorption material on lithium adsorption is investigated, and the results are shown in Table 3.

[0091] Table 3

[0092] Adsorbent addition amount (g / L) 0.1 0.2 1.0 2.0 3.0 4.0 5.0 Lithium adsorption capacity (mg / g) 92.37 91.63 90.59 89.25 88.94 88.17 87.94

[0093] From Table 3, it can be seen that when the addition amount of the adsorption material is selected as 0.1-5 g / L, the influence on lithium adsorption capacity is not large, and the lithium adsorption capacity is all above 85 mg / g, which has ultra-high lithium adsorption capacity.

[0094] Test Example 3

[0095] In this test example, the melamine-based adsorption material prepared in Example 5 is used to treat lithium-containing wastewater with different lithium concentrations and pH values, the addition amount of the adsorption material is 2 g / L, the adsorption test is carried out under the condition of 400 rpm of rotation speed and 50℃ of constant temperature for 2 h, the lithium concentration in the lithium-containing wastewater before and after adsorption is detected, the adsorption capacity of the adsorption material in each lithium-containing wastewater is calculated, and the initial composition of each lithium-containing wastewater and the test results are shown in Table 4.

[0096] Table 4

[0097]

[0098] From Table 4, it can be seen that the adsorption material provided by the present application can adsorb lithium from lithium-containing wastewater with different pH values and different lithium concentrations with ultra-high capacity, and the adsorption capacity in each lithium-containing wastewater is all above 81 mg / g.

[0099] The inventors also carried out the above test on the adsorption material of other examples, and the results are basically consistent, and due to the limited space, the changes or replacements that can be easily thought of by those skilled in the art within the technical range disclosed by the present application should be covered within the protection scope of the present application.

[0100] The above is only the preferred specific embodiment of the present application, but the protection scope of the present application is not limited thereto, any changes or replacements that can be easily thought of by those skilled in the art within the technical range disclosed by the present application should be covered within the protection scope of the present application.

Claims

1. A method for producing a melamine-based adsorbent material, characterized by, It comprises the following steps: (1) mixing benzene 12-crown-4 ether with a first catalyst, adding an organic solvent to dissolve, cooling, adding liquid bromine under stirring, warming to room temperature to react, removing unreacted liquid bromine, purifying, drying, evaporating to obtain a first product; (2) mixing the first product, 4-formylphenylboronic acid, potassium carbonate and a second catalyst, adding toluene and water, stirring under inert atmosphere to react, purifying, drying, evaporating to obtain a second product; (3) mixing the second product and melamine, then adding o-dichlorobenzene, n-butanol and acetic acid solution, mixing uniformly, reacting under vacuum to obtain a crude product, washing, centrifuging, drying to obtain the melamine-based adsorption material; The melamine-based adsorption material is a hexagonal covalent organic framework adsorption material connected by covalent bonds between melamine and benzene 12-crown-4 ether, and has a selective adsorption capacity of lithium ions >81 mg / g.

2. The method for producing a melamine-based adsorbent material according to claim 1, characterized by, In step (1), the molar ratio of benzene 12-crown-4 ether to the first catalyst is 1:6-1:

2.

3. The method for producing a melamine-based adsorbent material according to claim 2, characterized by, The first catalyst is iron powder.

4. The method for producing a melamine-based adsorbent material according to claim 2, characterized by, The organic solvent is dichloromethane.

5. The method for preparing the melamine-based adsorbent material according to claim 1, characterized in that, In step (1), the stirring speed is 300-500 rpm, and the reaction time is 2-6 h.

6. The method of producing a melamine-based adsorbent material according to any one of claims 1 to 5, characterized in that, In step (2), the molar ratio of the first product to 4-formylphenylboronic acid is 1:5-1:10, the molar ratio of the first product to potassium carbonate is 1:8-1:12, and the molar ratio of the first product to the second catalyst is 1:1-3:

1.

7. The method for producing a melamine-based adsorbent material according to claim 6, characterized by, The second catalyst is Pd(PPh3)4.

8. The method for preparing the melamine-based adsorbent material according to claim 1, characterized in that, In step (2), the volume ratio of toluene to water is 2:1-6:

1.

9. The method for producing a melamine-based adsorbent material according to claim 8, characterized by, The inert atmosphere is one or more of nitrogen, argon and helium.

10. The method of producing a melamine-based adsorbent material according to claim 1 or 8, characterized in that, In step (2), the reaction temperature is 100-120℃, the reaction time is 3-48 h, and the stirring speed is 300-500 rpm.

11. The method of producing a melamine-based adsorbent material according to any one of claims 1 to 5, characterized in that, In step (3), the molar ratio of melamine to the second product is 1:1-1:5, the volume ratio of o-dichlorobenzene to n-butanol is 1:2-1:6, and the volume ratio of o-dichlorobenzene to acetic acid solution is 1:1-1:

5.

12. The method of producing a melamine-based adsorbent material according to any one of claims 1 to 5, characterized in that, In step (3), the vacuum degree is 0.05-0.2 Pa, the reaction temperature is 110-150℃, and the reaction time is 3-48 h.

13. A melamine-based adsorption material prepared by the method of any one of claims 1-12.

14. Use of the melamine-based adsorption material of claim 13 in deep lithium extraction from lithium-containing wastewater.

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