Lithium ion sieve adsorbent, preparation method, lithium ion sieve adsorbent product and lithium ion adsorption separation method

Abstract

The invention relates to a lithium ion sieve adsorbent and a preparation method thereof, a lithium ion sieve adsorbent product and a lithium ion adsorption separation method, the lithium ion sieve adsorbent comprises 50-90% of a lithium ion sieve, 1-20% of a monatomic catalyst and an auxiliary agent, and the auxiliary agent comprises a binder and an optional additive; the lithium ion sieve is selected from a manganese-based lithium ion sieve, and the monatomic catalyst is selected from a nitrogen-doped carbon-based transition metal monatomic catalyst. The lithium ion sieve adsorbent provided by the invention has good lithium ion adsorption and separation capability, and high lithium extraction rate is realized; the lithium ion sieve adsorbent is matched with an eluent of persulfate to perform desorption regeneration after lithium enrichment, dissolution loss inhibition of the manganese-based lithium ion sieve in the desorption or regeneration process is achieved through synergistic reinforcement, and meanwhile the low manganese loss rate and efficient desorption of lithium ions are achieved; the lithium ion adsorption separation method for inhibiting the solution loss of the manganese-based lithium ion sieve, provided by the invention, is simple, efficient and excellent in effect, and can be well applied to industrial production.

Description

Technical Field

[0001] The present invention relates to the field of metal resource utilization, and in particular to a lithium ion sieve adsorbent and a preparation method thereof, a lithium ion sieve adsorbent product, and a lithium ion adsorption and separation method. Background Art

[0002] Global lithium resources exist in different types of solid ores, clays, lithium zeolites, salt lake brines, seawater, geothermal brines and oil and gas field brines. As the mining speed of lithium ore resources continues to accelerate, the reduction of lithium ore reserves and the high energy consumption, high cost and pollution problems brought about by mineral resource development have also affected its further development. In comparison, brine accounts for a large proportion of terrestrial lithium reserves and mining technology is constantly developing, so it has great potential in lithium resource extraction.

[0003] Common lithium extraction technologies for brine resources include salt gradient solar pond method, adsorption + membrane coupling method, and microfiltration, nanofiltration, reverse osmosis, electrodialysis, etc. with transmembrane process as the core. The solar pond method uses the negative temperature effect of lithium carbonate to achieve lithium ion concentration of carbonate brine. This process is not only limited by climatic conditions, but also the lithium-rich liquid concentrated by the solar pond method must be purified through subsequent processes. Adsorption and membrane coupling technology is the most perfect process in industrialization at present. It is very friendly to brine resources with low lithium ion concentration and can achieve selective enrichment of lithium ions in low-grade brine. At present, lithium ion sieve adsorbents are mainly divided into three categories: aluminum lithium ion sieve, titanium lithium ion sieve, and manganese lithium ion sieve. Among them, manganese lithium ion sieve has a higher adsorption capacity and is regarded as one of the most promising lithium ion sieve adsorbents. However, the bottleneck problem limiting the industrial application of manganese-based lithium ion sieve adsorbents is that due to the inherent properties of manganese itself, disproportionation reaction of the manganese center will occur during the elution process, which will lead to serious dissolution of the adsorbent. The failure of the adsorbent also introduces manganese ion impurities for the subsequent purification of lithium ions.

[0004] At present, researchers (CN 108622942A, CN 110773112A) mainly improve the dissolution problem of manganese-based lithium ion sieves by doping. The specific methods include grinding, solid phase sintering, sol-gel method, etc. The core purpose is to replace part of the low-valent manganese by doping to increase the average valence of manganese. This process not only involves the strict environmental conditions required for crystal heteroatom doping, but also may cause the introduction of new impurity elements. Therefore, in order to avoid the introduction of new impurity elements, some researchers (Zhu et al, Chemical Engineering Journal, 2014; Jia et al, Journal of Porous Materials, 2018) improve the stability of lithium ion sieves by granulating and molding powdery lithium ion sieves, but the ion sieve active sites with larger exposed surfaces still have the problem of serious manganese dissolution. Patent CN 116328713A discloses a method and application for preparing lithium ion sieve adsorbent particles, and the invention provides an improvement in the stability of ion sieves by improving the granulation molding method of ion sieve powders. Patent CN 116196882A discloses a method for preparing a titanium-based ion sieve, which improves the adsorption capacity of the ion sieve by replacing lithium salt with potassium salt during the synthesis process. Patent CN 116351380A discloses a method for preparing a low-cost layered lithium ion sieve, which specifically uses solid waste residue as a raw material to prepare a high-performance lithium ion sieve to reduce the cost of raw materials. Through the analysis of public patents, it can be found that researchers mostly improve the stability of ion sieves from the perspective of molding and preparation technology, while the eluent still uses dilute acid, which makes it impossible to improve the dissolution loss of the ion sieve during the desorption process.

[0005] Manganese-based lithium ion sieves have serious manganese dissolution problems in the desorption stage after enriching lithium ions in the solution, as well as the problem of limited cycle life. How to obtain a lithium ion sieve adsorbent with a high lithium extraction rate and how to avoid or effectively reduce the sieve dissolution phenomenon of manganese-based lithium ion sieves in the desorption stage are technical problems that need to be solved urgently. Summary of the invention

[0006] The present invention provides a lithium ion sieve adsorbent and a preparation method thereof, a lithium ion sieve adsorbent product, and a lithium ion adsorption and separation method, with the aim of providing a lithium ion sieve adsorbent with a high lithium extraction rate, avoiding or reducing the dissolution loss of the manganese-based lithium ion sieve adsorbent in the desorption stage, and achieving a low manganese loss rate.

[0007] In a first aspect, the present invention relates to a lithium ion sieve adsorbent, comprising the following components in proportion by mass based on the total mass of the lithium ion sieve adsorbent:

[0008] Lithium ion sieve 50~90%,

[0009] Single atom catalyst 1~20%,

[0010] and auxiliary agents, the auxiliary agents comprising a binder and optional additives;

[0011] Wherein, the lithium ion sieve is selected from a manganese-based lithium ion sieve, and the single-atom catalyst is selected from a nitrogen-doped carbon-based transition metal single-atom catalyst.

[0012] Optionally, the manganese-based lithium ion is selected from H 1.6 Mn 1.6 O4, HMn2O4, H4Mn5O 12 and H 1.33 Mn 1.67 A combination of one or more of O4.

[0013] Optionally, the nitrogen-doped carbon-based transition metal single-atom catalyst is selected from a combination of one or more of NC / Co, NC / Ni and NC / Mn.

[0014] Optionally, the binder is selected from one or more combinations of polyvinyl chloride, polyvinylidene fluoride, styrene-butadiene rubber and carboxymethyl cellulose.

[0015] Optionally, the additive is selected from one or more combinations of polyacrylonitrile, chitosan, cellulose, sodium alginate, agar and polyacrylamide.

[0016] Optionally, the mass ratio of the binder to the additive is (2-10):1; and / or,

[0017] The lithium ion sieve adsorbent includes the following components in proportion by mass based on the total mass of the lithium ion sieve adsorbent:

[0018] Lithium ion sieve 60~80%,

[0019] Single atom catalyst 2~7%,

[0020] Binder 10-30%,

[0021] Additives 2~7%.

[0022] In a second aspect, the present invention relates to a method for preparing the lithium ion sieve adsorbent described in the first aspect, the preparation method comprising the following steps:

[0023] (1) dissolving a binder and optional additives in an organic solvent to obtain a binder solution;

[0024] (2) dispersing a lithium ion sieve precursor and a single atom catalyst in the binder solution to obtain a slurry;

[0025] Wherein, the lithium ion sieve precursor is selected from a manganese-based lithium ion sieve precursor, and the single atom catalyst is selected from a nitrogen-doped carbon-based transition metal single atom catalyst;

[0026] (3) dropping the slurry into water to form it, and then soaking it in an acid solution to remove lithium, thereby obtaining the lithium ion sieve adsorbent.

[0027] Optionally, the manganese-based lithium ion sieve precursor is selected from Li 1.6 Mn 1.6 O4, LiMn2O4, Li4Mn5O 12 and Li 1.33 Mn 1.67 A combination of one or more of O4.

[0028] Optionally, in step (1):

[0029] The ratio of the total mass of the binder and the additive to the volume of the organic solvent is 1 g: 10 to 20 mL;

[0030] The organic solvent is selected from one or more combinations of N,N'-dimethylformamide, propylene glycol, dimethylformamide, isopropyl acetate, dimethyl sulfoxide and N-methylpyrrolidone; and / or,

[0031] In step (2):

[0032] The mass of the single atom catalyst accounts for 0.1-10% of the mass of the lithium ion sieve precursor.

[0033] The ratio of the total mass of the lithium ion sieve precursor and the single atom catalyst to the volume of the binder solution is 1 g: 2 to 6 mL; and / or,

[0034] In step (3):

[0035] The slurry is dripped into the water at a speed of 1 to 10 mL / min.

[0036] The acid solution is a 0.01-5 mol / L hydrochloric acid solution,

[0037] The soaking time is 1 to 72 hours;

[0038] Step (3) also includes cleaning and drying after immersing in an acid solution for lithium removal.

[0039] The drying temperature is 200° C. or lower.

[0040] In a third aspect, the present invention relates to a lithium ion sieve adsorbent product, comprising a lithium ion sieve adsorbent and an eluent; the lithium ion sieve adsorbent is selected from the lithium ion sieve adsorbent described in the first aspect or is prepared by the preparation method described in the second aspect; the eluent is selected from persulfate;

[0041] The eluent is preferably self-contained S2O8 2- and salts of inorganic cations;

[0042] The eluent is further preferably selected from a combination of one or more of Na2S2O8, K2S2O8 and (NH4)2S2O8.

[0043] In a fourth aspect, the present invention relates to a lithium ion adsorption and separation method for inhibiting the dissolution loss of a manganese-based lithium ion sieve, comprising the following steps:

[0044] (S1) contacting a lithium ion-containing solution with the lithium ion sieve adsorbent described in the first aspect, or contacting the lithium ion sieve adsorbent prepared by the preparation method described in the second aspect, to obtain a lithium ion sieve adsorbent after lithium adsorption and a solution after lithium desorption;

[0045] (S2) contacting the lithium ion sieve adsorbent after adsorbing lithium with an aqueous solution of an eluent to obtain a regenerated lithium ion sieve adsorbent;

[0046] Wherein, the eluent is selected from persulfate, preferably from S2O8 2- and a salt of an inorganic cation, and further preferably a combination of one or more selected from Na2S2O8, K2S2O8 and (NH4)2S2O8.

[0047] Optionally, in step (S2), the concentration of the aqueous solution of the eluent is 0.05-2 mol / L, preferably 0.1-0.5 mol / L;

[0048] and / or,

[0049] The liquid-to-solid mass ratio of the aqueous solution of the eluent to the lithium ion sieve adsorbent after lithium adsorption is (50-1000):1, preferably (100-900):1;

[0050] The contact time between the lithium ion sieve adsorbent after lithium adsorption and the aqueous solution of the eluent is 1 to 72 hours.

[0051] Beneficial effects:

[0052] The lithium ion sieve adsorbent provided by the present invention has excellent lithium ion adsorption and separation capabilities, and achieves a high lithium extraction rate; the lithium ion sieve adsorbent of the present invention is combined with a persulfate eluent to perform desorption and regeneration after lithium enrichment, and synergistically strengthens the suppression of dissolution loss of the manganese-based lithium ion sieve during the desorption or regeneration process, while achieving a low manganese loss rate and efficient desorption of lithium ions; the lithium ion adsorption and separation method for suppressing dissolution loss of the manganese-based lithium ion sieve provided by the present invention is simple and efficient, has excellent effects, and can be well applied in industrial production. DETAILED DESCRIPTION

[0053] The present invention is further described in detail below through examples. Through these examples, the features and advantages of the present invention will become clearer and more specific.

[0054] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0055] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0056] In a first aspect, the present invention relates to a lithium ion sieve adsorbent, comprising the following components in proportion by mass based on the total mass of the lithium ion sieve adsorbent:

[0057] Lithium ion sieve 50~90%,

[0058] Single atom catalyst 1~20%,

[0059] and auxiliary agents, the auxiliary agents comprising a binder and optional additives;

[0060] Wherein, the lithium ion sieve is selected from a manganese-based lithium ion sieve, and the single-atom catalyst is selected from a nitrogen-doped carbon-based transition metal single-atom catalyst.

[0061] It should be noted that a single-atom catalyst is innovatively introduced into the lithium-ion sieve adsorbent of the present invention, and the lithium-ion sieve adsorbent can maintain high efficiency in lithium ion adsorption and separation, and has a high lithium extraction rate when used for adsorption and separation of lithium-ion-containing solutions; and the lithium-ion sieve adsorbent containing the above-mentioned single-atom catalyst in the present application, when in contact with an eluent solution containing persulfate for lithium desorption and regeneration, can effectively inhibit the sieve dissolution phenomenon of the manganese-based lithium-ion sieve in the desorption stage, while achieving a low manganese loss rate.

[0062] It should be noted that the optional additives mean that the lithium ion sieve adsorbent may contain any proportion of additives or no additives. In the lithium ion sieve adsorbent, the mass proportion of the lithium ion sieve may be 60%, 70%, 75%, 80%, etc. In the lithium ion sieve adsorbent of the present application, the sum of the mass proportions of the lithium ion sieve, the single atom catalyst, the binder and the optional additives is 100%.

[0063] According to a specific embodiment of the lithium ion sieve adsorbent according to the first aspect of the present invention, the manganese-based lithium ion sieve is selected from H 1.6 Mn 1.6 O4, HMn2O4, H4Mn5O 12 and H 1.33 Mn 1.67 A combination of one or more of O4.

[0064] It should be noted that the lithium ion sieve adsorbent formed by compounding one or more of the above-mentioned manganese-based lithium ion sieves with single-atom catalysts and additives can better synergize with each other, thereby further improving the lithium adsorption and separation effect of the lithium ion sieve adsorbent, and when it is in contact with an eluent solution containing persulfate for lithium desorption regeneration, it can further reduce the manganese loss rate, that is, better inhibit the sieve dissolution loss in the lithium desorption process.

[0065] According to a specific embodiment of the lithium ion sieve adsorbent according to the first aspect of the present invention, the nitrogen-doped carbon-based transition metal single-atom catalyst is selected from a combination of one or more of NC / Co, NC / Ni and NC / Mn.

[0066] It should be noted that the catalysts used in this application are not limited to the above-mentioned nitrogen-doped carbon-based transition metal single atom catalysts. Any catalyst that can efficiently catalyze the conversion of persulfate in the eluent or desorbent into sulfate radicals falls within the scope of this application.

[0067] It should be noted that the combination of one or more of the above NC / Co, NC / Ni and NC / Mn as the single atom catalyst and H 1.6 Mn 1.6 O4, HMn2O4, H4Mn5O 12 and H 1.33 Mn 1.67 O4 is compounded with one or more combinations thereof, the lithium extraction rate of the lithium ion sieve adsorbent formed is further improved, and the manganese loss rate is further reduced when it is contacted with an eluent solution containing persulfate for lithium removal and regeneration.

[0068] It should be noted that the above-mentioned NC / Co, NC / Ni and NC / Mn can be prepared using commercially available finished reagents, or by conventional methods in the art. For example, a certain amount of 2,5-dihydro-1H-pyrrole and 2,6-diacetylpyridine can be placed in an ethanol solution of oxalic acid and fully stirred, and then Co salt, Ni salt or Mn salt is added and fully stirred to form a solid precipitate; the solid precipitate obtained after filtering the above solution is vacuum dried, and the vacuum dried product is calcined at high temperature under a nitrogen atmosphere, and naturally cooled to obtain NC / Co, NC / Ni or NC / Mn.

[0069] According to the lithium ion sieve adsorbent of the first aspect of the present invention, the binder is selected from a combination of one or more of polyvinyl chloride, polyvinylidene fluoride, styrene-butadiene rubber and carboxymethyl cellulose.

[0070] According to the lithium ion sieve adsorbent of the first aspect of the present invention, the additive is selected from a combination of one or more of polyacrylonitrile, chitosan, cellulose, sodium alginate, agar and polyacrylamide.

[0071] It should be noted that the use of the above-mentioned binder and additives makes the lithium ion sieve adsorbent of the present application have good stability, and can maintain a high lithium extraction rate and a low manganese loss rate for a longer period of time.

[0072] According to the lithium ion sieve adsorbent of the first aspect of the present invention, the mass ratio of the binder to the additive is (2-10): 1; and / or,

[0073] The lithium ion sieve adsorbent includes the following components in proportion by mass based on the total mass of the lithium ion sieve adsorbent:

[0074] Lithium ion sieve 60~80%,

[0075] Single atom catalyst 2~7%,

[0076] Binder 10-30%,

[0077] Additives 2~7%.

[0078] It should be noted that, as a preferred embodiment, the mass ratio of the binder and the additive is controlled as above, and / or the mass proportion of the lithium ion sieve, the single atom catalyst, the binder and the additive in the lithium ion sieve adsorbent is controlled as above, the lithium adsorption and separation effect of the obtained lithium ion sieve adsorbent is further improved, that is, the lithium extraction rate is further improved, and when it is contacted with an eluent solution containing persulfate for lithium removal regeneration, the manganese loss rate can be further reduced, that is, the sieve dissolution loss in the lithium removal process is better suppressed.

[0079] In a second aspect, the present invention relates to a method for preparing the lithium ion sieve adsorbent described in the first aspect, the preparation method comprising the following steps:

[0080] (1) dissolving a binder and optional additives in an organic solvent to obtain a binder solution;

[0081] (2) dispersing a lithium ion sieve precursor and a single atom catalyst in the binder solution to obtain a slurry;

[0082] Wherein, the lithium ion sieve precursor is selected from a manganese-based lithium ion sieve precursor, and the single atom catalyst is selected from a nitrogen-doped carbon-based transition metal single atom catalyst;

[0083] (3) dropping the slurry into water to form it, and then soaking it in an acid solution to remove lithium, thereby obtaining the lithium ion sieve adsorbent.

[0084] It should be noted that lithium ion sieve precursors such as Li 1.6 Mn 1.6 O4, LiMn2O4, after being soaked and de-lithified in step (3), is converted into lithium ion sieve H 1.6 Mn 1.6 When preparing the lithium ion sieve adsorbent, the single atom catalyst is retained in the prepared lithium ion sieve adsorbent. The lithium ion sieve precursor such as Li 1.6 Mn 1.6 O4, LiMn2O4 are converted into lithium ion sieve H 1.6 Mn 1.6 O4, HMn2O4, and the auxiliary agent remains basically unchanged. After the above steps (1) to (3), the organic solvent is removed, and the binder, additives, single-atom catalyst and lithium ion sieve generated by delithiation together constitute the lithium ion sieve adsorbent. The preparation method of the present invention innovatively dopes the single-atom catalyst during the granulation molding process, so that the single-atom catalyst is evenly dispersed in the lithium ion sieve adsorbent after molding; the lithium ion sieve adsorbent prepared by introducing the single-atom catalyst has a good lithium ion adsorption and separation ability, and in the process of delithiation with persulfate as an eluent to regenerate the adsorbent, it can effectively avoid or greatly reduce the occurrence of manganese dissolution.

[0085] It should be noted that in step (3), the reverse solvent conversion method is used to drop the black slurry into deionized water to form a sphere, and then the pre-lithiation of the lithium ion sieve is achieved by soaking in an acid solution. The lithium ion sieve adsorbent prepared by the method of the present application can well introduce the single-atom catalyst, and the lithium ion sieve converted from the single-atom catalyst and the lithium ion sieve precursor is evenly and stably distributed in the spherical lithium ion sieve adsorbent. The prepared lithium ion sieve adsorbent has a good lithium ion adsorption and separation ability, and can effectively inhibit the occurrence of manganese dissolution loss in the process of lithium desorption regeneration using persulfate as an eluent, and at the same time achieve good regeneration.

[0086] According to a specific embodiment of the method for preparing the lithium ion sieve adsorbent according to the second aspect of the present invention, the manganese-based lithium ion sieve precursor is selected from Li 1.6 Mn 1.6 O4, LiMn2O4, Li4Mn5O 12 and Li 1.33 Mn 1.67 A combination of one or more of O4.

[0087] It should be noted that in the preparation method of the present invention, after being soaked in the acid solution in step (3), the manganese-based lithium ion sieve precursor Li 1.6 Mn 1.6 O4, LiMn2O4, Li4Mn5O 12 and Li 1.33 Mn 1.67 O4 are converted into manganese-based lithium ion sieve H 1.6 Mn 1.6 O4, HMn2O4, H4Mn5O 12 and H 1.33 Mn 1.67 O4; In the lithium ion sieve adsorbent obtained by compounding such a manganese-based lithium ion sieve with the above-mentioned single-atom catalyst and auxiliary agent, the components synergize with each other, so that the lithium adsorption and separation effect of the lithium ion sieve adsorbent is further improved, and when it is in contact with an eluent solution containing persulfate for lithium desorption regeneration, the manganese loss rate can be further reduced, that is, the sieve dissolution loss in the lithium desorption process is better suppressed.

[0088] According to a specific embodiment of the method for preparing the lithium ion sieve adsorbent according to the second aspect of the present invention, in step (1):

[0089] The ratio of the total mass of the binder and the additive to the volume of the organic solvent is 1 g: 10 to 20 mL;

[0090] The organic solvent is selected from one or more combinations of N,N'-dimethylformamide, propylene glycol, dimethylformamide, isopropyl acetate, dimethyl sulfoxide and N-methylpyrrolidone; and / or,

[0091] In step (2):

[0092] The mass of the single atom catalyst accounts for 0.1-10% of the mass of the lithium ion sieve precursor.

[0093] The ratio of the total mass of the lithium ion sieve precursor and the single atom catalyst to the volume of the binder solution is 1 g: 2 to 6 mL; and / or,

[0094] In step (3):

[0095] The slurry is dripped into the water at a speed of 1 to 10 mL / min.

[0096] The acid solution is a 0.01-5 mol / L hydrochloric acid solution,

[0097] The soaking time is 1 to 72 hours;

[0098] Step (3) also includes cleaning and drying after immersing in an acid solution for lithium removal.

[0099] The drying temperature is 200° C. or lower.

[0100] It should be noted that step (3) also includes cleaning and drying after immersion in the acid solution for delithiation. The cleaning can be done with deionized water. The volume ratio of the lithium ion sieve adsorbent to water in the cleaning stage can be (0.5-5):1; the drying temperature is below 200°C to ensure that the structure of the formed lithium ion sieve adsorbent is not transformed or destroyed.

[0101] It should be noted that in the preparation method of the lithium ion sieve adsorbent of the present application, the above-mentioned organic solvent is selected by controlling the ratio of the total mass of the binder and the additive to the volume of the organic solvent in step (1) as above; in step (2), the mass proportion of the single atom catalyst in the lithium ion sieve precursor is controlled as above, and the conditions of step (3) are controlled at the same time, so that the single atom catalyst, lithium ion sieve, binder and additive in the prepared lithium ion sieve adsorbent are stably connected to form a lithium ion sieve adsorbent with excellent performance, which can further improve the lithium extraction rate and reduce the manganese loss rate when used for adsorption and separation of lithium ion-containing solutions.

[0102] In a third aspect, the present invention relates to a lithium ion sieve adsorbent product, comprising a lithium ion sieve adsorbent and an eluent; the lithium ion sieve adsorbent is selected from the lithium ion sieve adsorbent described in the first aspect of the present invention or is prepared by the preparation method described in the second aspect of the present invention; the eluent is selected from persulfate;

[0103] The eluent is preferably self-contained S2O8 2- and salts of inorganic cations;

[0104] The eluent is further preferably selected from a combination of one or more of Na2S2O8, K2S2O8 and (NH4)2S2O8.

[0105] It should be noted that the lithium ion sieve adsorbent of the present invention contains the single atom catalyst, and the eluent used for regenerating the lithium ion sieve adsorbent is selected from the above-mentioned persulfate. Under the catalysis of the above-mentioned single atom catalyst, the desorption liquid containing the eluent can generate hydrogen ions and sulfate radicals through mild conditions. The generated hydrogen ions can replace the lithium ions adsorbed in the lithium ion sieve adsorbent, so that the adsorbent can be regenerated, and the generated sulfate radicals can effectively inhibit the dissolution of manganese. When the eluent is selected from one or more combinations of Na2S2O8, K2S2O8 and (NH4)2S2O8, while maintaining a high lithium extraction rate, it can further reduce the manganese loss rate during the desorption process.

[0106] In a fourth aspect, the present invention relates to a lithium ion adsorption and separation method for inhibiting the dissolution loss of a manganese-based lithium ion sieve, comprising the following steps:

[0107] (S1) contacting the lithium ion-containing solution with the lithium ion sieve adsorbent described in the first aspect, or contacting the lithium ion sieve adsorbent prepared by the preparation method described in the second aspect, to obtain the lithium ion sieve adsorbent after lithium adsorption and the solution after lithium desorption;

[0108] (S2) contacting the lithium ion sieve adsorbent after adsorbing lithium with an aqueous solution of an eluent to obtain a regenerated lithium ion sieve adsorbent;

[0109] Wherein, the eluent is selected from persulfate, preferably from S2O8 2- and a salt of an inorganic cation, and further preferably a combination of one or more selected from Na2S2O8, K2S2O8 and (NH4)2S2O8.

[0110] It should be noted that the inhibition of the dissolution process of the manganese-based lithium ion sieve is achieved by introducing the above-mentioned nitrogen-doped carbon-based transition metal single-atom catalyst and adapting the method of high-efficiency eluent during the manganese-based lithium ion sieve forming process. The present invention utilizes a catalyst doped into the manganese-based lithium ion sieve adsorbent and uses a persulfate eluent (desorption liquid) in conjunction with the use of a catalyst. In the elution process of the lithium ion sieve after adsorbing lithium ions, the persulfate decomposes to produce hydrogen ions for replacing lithium ions (lithium ions adsorbed in the manganese-based lithium ion sieve), and the single-atom catalyst catalyzes the persulfate to produce sulfate radicals as electron acceptors. The sulfate radicals produced by the catalytic persulfate can be used as electron acceptors to accept the electrons produced by unstable Mn (III), thereby promoting the conversion of Mn (III) into relatively stable Mn (IV), achieving the inhibition of the disproportionation process of Mn (III), and then effectively inhibiting the dissolution of the manganese-based lithium ion sieve, while achieving efficient lithium desorption of the manganese-based lithium ion sieve.

[0111] It should be noted that after the lithium ion sieve adsorbent after adsorption of lithium is contacted with the aqueous solution of the eluent, the regenerated lithium ion sieve adsorbent can be obtained. For example, the Li 1.6 Mn 1.6 O4, LiMn2O4, after contact with the eluent, they are regenerated and converted into H 1.6 Mn 1.6 O4, HMn2O4. Lithium ions and sulfate radicals remain in the eluent aqueous solution (solution after desorption), and the sodium carbonate precipitation separation method can be used to convert the obtained lithium ions into lithium carbonate precipitates.

[0112] In the prior art, during the process of eluting lithium ions from a manganese-based lithium ion sieve, Mn(III) inevitably undergoes a disproportionation reaction to produce Mn(II) and Mn(IV). The main process is as follows: during the acid elution process, the trace amount of trivalent manganese ions in the internal phase are unstable in nature, and will release an electron to maintain the stability of the properties. The released electrons are freely transferred to the quadrivalent manganese ions in the surface phase, and the quadrivalent manganese ions that capture enough electrons are reduced in price to form divalent manganese ions, which are dissolved in the eluent, ultimately leading to the failure of the manganese-based lithium ion sieve adsorbent, and the introduction of a large amount of manganese ion impurities into the eluent, thus causing the sieve loss or dissolution loss of the lithium ion sieve. The present invention achieves efficient desorption of lithium ions while suppressing manganese dissolution loss by adapting the design of a manganese-based lithium ion sieve with an eluent. Considering that the electron transfer of trivalent manganese triggers the subsequent dissolution process, the present invention designs the introduction of free radicals as electron acceptors to avoid the appearance of divalent manganese that is easily soluble, while persulfate reacts with water to produce hydrogen ions for replacing lithium ions in the lithium ion sieve. Therefore, the present invention utilizes persulfate as an eluent, and introduces a single-atom catalyst that catalyzes persulfate to produce sulfate radicals into the ion sieve during the granulation and molding process of the manganese-based lithium ion sieve, thereby achieving the suppression of manganese dissolution loss and efficient replacement of lithium ions during the elution process.

[0113] In general, by introducing a catalyst and a persulfate eluent in a clever combination into the manganese-based lithium ion sieve, the persulfate is used to generate hydrogen ions and sulfate radicals during the elution process to achieve efficient elution of lithium in the manganese-based lithium ion sieve and inhibition of the manganese dissolution process.

[0114] According to a specific embodiment of the lithium ion adsorption separation method according to the fourth aspect of the present invention, in step (S2), the concentration of the aqueous solution of the eluent is 0.05-2 mol / L, preferably 0.1-0.5 mol / L;

[0115] and / or,

[0116] The liquid-to-solid mass ratio of the aqueous solution of the eluent to the lithium ion sieve adsorbent after lithium adsorption is (50-1000):1, preferably (100-900):1;

[0117] The contact time between the lithium ion sieve adsorbent after lithium adsorption and the aqueous solution of the eluent is 1 to 72 hours.

[0118] It should be noted that by controlling the concentration of the aqueous solution of the eluent, the liquid-to-solid mass ratio of the aqueous solution of the eluent and the lithium ion sieve adsorbent after lithium adsorption, and the contact time between the lithium ion sieve adsorbent after lithium adsorption and the aqueous solution of the eluent as above, the lithium ion sieve adsorbent after lithium adsorption can be better delithiation process to obtain a completely regenerated lithium ion sieve adsorbent, and the sieve loss during the desorption process can be further suppressed, further reducing the manganese loss rate, and the regenerated lithium ion sieve adsorbent can be better used again, effectively extending the service life.

[0119] The present invention is further described in detail by way of examples below, but the present invention is not limited thereto. In the following examples, unless otherwise specified, the experimental instruments and raw materials involved are all commercially available products.

[0120] The lithium ion sieve Li used in the following examples 1.6 Mn 1.6 O4、Li4Mn5O 12 , Li 1.33 Mn 1.67 O4 was prepared by the following preparation example. The nitrogen-doped carbon-based transition metal single-atom catalysts used in the following examples: NC / Co catalyst, NC / Mn catalyst and NC / Ni catalyst were prepared by the following preparation example.

[0121] Lithium ion sieve preparation example

[0122] 1. Li 1.6 Mn 1.6 O4 Preparation Example

[0123] First, 0.5M lithium hydroxide solution was added to a high-pressure reactor, and Mn2O3 was added according to a certain lithium-manganese substance ratio (Li:Mn=1:1). After the hydrothermal temperature was 250°C and the hydrothermal time was 15h, orthorhombic LiMnO2 was obtained; then LiMnO2 was calcined at 450°C for 8h to obtain Li 1.6 Mn 1.6 O4.

[0124] 2. Li4Mn5O 12 Preparation Example

[0125] LiOH H2O and MnCO3 were weighed according to the molar ratio of lithium ion to manganese ion of 1:1.23, deionized water was added, ball milled and mixed, and then vacuum dried to obtain a precursor. The precursor was placed in a tube furnace and sintered at 220℃ for 4h and then at 420℃ for 8h in an air atmosphere to obtain Li4Mn5O12 .

[0126] 3. Li 1.33 Mn 1.67 O4 Preparation Example

[0127] Li2CO3 and MnCO3 were uniformly mixed according to the Li / Mn molar ratio of 1.33:1.67; the mixture was placed in a magnetic boat and calcined at 500°C for 4h to obtain Li 1.33 Mn 1.67 O4.

[0128] Preparation example of nitrogen-doped carbon-based transition metal single atom catalyst

[0129] 1. Preparation example of NC / Co catalyst

[0130] 0.5 g of 2,5-dihydro-1H-pyrrole and 0.5 g of 2,6-diacetylpyridine were placed in a 0.5 M ethanolic oxalic acid solution and stirred for 12 h, followed by the addition of 0.2 g of cobalt chloride, which was stirred thoroughly to form a solid precipitate. The solid precipitate obtained after filtering the above solution was placed in a vacuum drying oven at 80 ° C for 8 h; the dried product was heat treated at 950 ° C for 1 h under a nitrogen atmosphere, and naturally cooled to room temperature to obtain NC / Co.

[0131] 2. Preparation example of NC / Mn catalyst

[0132] 0.6 g of 2,5-dihydro-1H-pyrrole and 0.4 g of 2,6-diacetylpyridine were placed in a 0.5 M ethanolic oxalic acid solution and stirred for 12 h, followed by the addition of 0.3 g of manganese chloride, which was stirred thoroughly to form a solid precipitate. The solid precipitate obtained after filtering the above solution was placed in a vacuum drying oven at 80 ° C for 8 h; the dried product was heat treated at 950 ° C for 1 h under a nitrogen atmosphere, and naturally cooled to room temperature to obtain NC / Mn.

[0133] 3. Preparation example of NC / Ni catalyst

[0134] 0.5 g of 2,5-dihydro-1H-pyrrole and 0.5 g of 2,6-diacetylpyridine were placed in a 0.5 M ethanolic oxalic acid solution and stirred for 12 h, followed by the addition of 0.3 g of nickel chloride, which was stirred thoroughly to form a solid precipitate. The solid precipitate obtained after filtering the above solution was placed in a vacuum drying oven at 80 ° C for 8 h; the dried product was heat treated at 950 ° C for 1 h under a nitrogen atmosphere, and naturally cooled to room temperature to obtain NC / Ni.

[0135] The calculation method of the extraction rate of lithium in the following examples is:

[0136]

[0137] C0 is the Li ion concentration in the initial lithium solution, g / L,

[0138] C1 is the Li ion concentration in the solution after delithiation, g / L.

[0139] The calculation method of manganese loss rate is as follows:

[0140]

[0141] C Mn is the concentration of manganese ions in the solution after desorption, g / L; V 脱附液 is the volume of solution after desorption, L;

[0142] M is H 1.6 Mn 1.6 O4、H4Mn5O 12 , or H 1.33 Mn 1.67 The molar mass of O4 is g / mol;

[0143] m is the H in the adsorbent product 1.6 Mn 1.6 O4、H4Mn5O 12 , or H 1.33 Mn 1.67 The mass of O4, g;

[0144] x is H 1.6 Mn 1.6 O4、H4Mn5O 12 , or H 1.33 Mn 1.67 The relative atomic mass of Mn in O4;

[0145] 54.95 is the molar mass of Mn in g / mol.

[0146] Example 1

[0147] (1) dissolving agar and 0.5 g of polyvinyl chloride in a mass ratio of 20% (the proportion of agar in polyvinyl chloride) in 8.7 mL of N,N'-dimethylformamide and stirring continuously to obtain a homogeneous solution which is used as a binder solution;

[0148] (2) Take 2g Li 1.6 Mn 1.6 After the O4 ion sieve powder and 0.1 g NC / Co catalyst powder are fully mixed, they are added to the above-mentioned binder solution and stirred at 100 r / min for 24 h to obtain a black slurry;

[0149] (3) dropping the black slurry into deionized water at a flow rate of 2 mL / min to form a shape;

[0150] (4) soaking the molded ion sieve obtained in the above process in 0.1 mol / L hydrochloric acid for 24 hours to obtain manganese-based lithium ion sieve spherical particles doped with a high-efficiency catalyst;

[0151] (5) washing the molded ion sieve obtained in the above process with deionized water and drying it to obtain an adsorbent product to be used, wherein the content of lithium ion sieve powder in the molded ion sieve is about 74%;

[0152] (6) taking 0.5 g of the above-formed ion sieve and immersing it in 20 ml of a lithium solution with a lithium concentration of 50 ppm (the lithium solution is prepared by lithium hydroxide monohydrate), and vibrating it in a constant temperature vibration box at room temperature at a speed of 100 rpm for 24 h to obtain an ion sieve after Li adsorption and a solution after de-lithiation;

[0153] (7) using an aqueous solution of ammonium persulfate as an eluent to desorb the ion sieve after adsorbing Li to obtain a desorbed solution, wherein the concentration of the eluent is controlled at 0.3 mol / L, the liquid-to-solid mass ratio is controlled at 500:1, and the desorption time is controlled at 12 h;

[0154] (8) ICP-OES was used to test the concentration of Mn ions in the solution after desorption and the concentration of Li in the solution after delithiation. The lithium extraction rate was calculated to be 98.1% and the manganese loss rate was 0.05%.

[0155] Example 2

[0156] (1) Chitosan and 0.675 g of carboxymethyl cellulose were dissolved in 12 mL of propylene glycol at a mass ratio of 30% (the proportion of chitosan in carboxymethyl cellulose) and stirred continuously to obtain a homogeneous solution which was used as a binder solution;

[0157] (2) Take 3g Li4Mn5O 12 After the ion sieve powder and 0.2 g NC / Mn catalyst powder were fully mixed, they were added to the above-mentioned binder solution and stirred at 300 r / min for 37 h to obtain a black slurry;

[0158] (3) dropping the black slurry into deionized water at a flow rate of 2 mL / min to form a shape;

[0159] (4) soaking the molded ion sieve obtained in the above process in 0.2 mol / L hydrochloric acid for 15 h to obtain manganese-based lithium ion sieve spherical particles doped with a high-efficiency catalyst;

[0160] (5) washing the molded ion sieve obtained in the above process with deionized water and drying it to obtain an adsorbent product to be used, wherein the content of lithium ion sieve powder in the molded ion sieve is 75%;

[0161] (6) taking 1 g of the above-formed ion sieve and immersing it in 20 mL of a lithium solution with a lithium concentration of 100 ppm (the lithium solution is prepared by lithium hydroxide monohydrate), and vibrating it in a constant temperature vibration box at room temperature at a speed of 240 rpm for 30 h to obtain an ion sieve after Li adsorption and a solution after lithium desorption;

[0162] (7) Using potassium persulfate aqueous solution as eluent, the ion sieve obtained after adsorption of Li was desorbed to obtain a desorbed solution, the eluent concentration was controlled at 1 mol / L, the liquid-to-solid mass ratio was controlled at 450:1, and the time was controlled at 32 h;

[0163] (8) ICP-OES was used to test the concentration of Mn ions in the solution after desorption and the concentration of Li in the solution after delithiation. The lithium extraction rate was calculated to be 95.3% and the manganese loss rate was 0.03%.

[0164] Example 3

[0165] (1) Chitosan and 0.5 g of polyvinyl chloride were dissolved in 9 mL of N,N'-dimethylformamide (DMF) at a mass ratio of 20% (the proportion of chitosan in polyvinyl chloride) and stirred continuously to obtain a homogeneous solution which was used as a binder solution;

[0166] (2) Take 2g Li 1.33 Mn 1.67 After the O4 ion sieve powder and 0.1 g NC / Ni catalyst powder were fully mixed, they were added to the above-mentioned binder solution and stirred continuously at 200 r / min for 12 h to obtain a black slurry;

[0167] (3) dropping the black slurry into deionized water at a flow rate of 5 mL / min to form a shape;

[0168] (4) soaking the molded ion sieve obtained in the above process in 0.5 mol / L hydrochloric acid for 7 hours to obtain manganese-based lithium ion sieve spherical particles doped with a high-efficiency catalyst;

[0169] (5) The formed ion sieve obtained in the above process is washed with deionized water and dried to obtain an adsorbent product to be used, wherein the content of lithium ion sieve powder in the formed ion sieve is 74%;

[0170] (6) taking 1 g of the above-formed ion sieve and immersing it in 20 ml of a lithium solution with a lithium concentration of 100 ppm (the lithium solution is prepared by lithium hydroxide monohydrate), and vibrating it in a constant temperature vibration box at room temperature at a speed of 200 rpm for 30 h to obtain an ion sieve after Li adsorption and a solution after lithium desorption;

[0171] (7) using a sodium persulfate aqueous solution as an eluent to desorb the ion sieve after adsorbing Li to obtain a desorbed solution, wherein the eluent concentration is controlled at 0.5 mol / L, the liquid-to-solid mass ratio is controlled at 600:1, and the desorption time is controlled at 12 h;

[0172] (8) ICP-OES was used to test the concentration of Mn ions in the solution after desorption and the concentration of Li in the solution after delithiation. The lithium extraction rate was calculated to be 94.1% and the manganese loss rate was 0.1%.

[0173] Example 4

[0174] (1) dissolving agar and 0.5 g of polyvinyl chloride in a mass ratio of 20% (the proportion of agar in polyvinyl chloride) in 9.3 mL of N,N'-dimethylformamide and stirring continuously to obtain a homogeneous solution which is used as a binder solution;

[0175] (2) Take 2g Li 1.6 Mn 1.6 After the O4 ion sieve powder and 0.1 g NC / Co catalyst powder are fully mixed, they are added to the above-mentioned binder solution and stirred at 100 r / min for 24 h to obtain a black slurry;

[0176] (3) dropping the black slurry into deionized water at a flow rate of 2 mL / min to form a shape;

[0177] (4) soaking the molded ion sieve obtained in the above process in 0.1 mol / L hydrochloric acid for 24 hours to obtain manganese-based lithium ion sieve spherical particles doped with a high-efficiency catalyst;

[0178] (5) washing the molded ion sieve obtained in the above process with deionized water and drying it to obtain an adsorbent product to be used, wherein the content of lithium ion sieve powder in the molded ion sieve is about 74%;

[0179] (6) taking 0.5 g of the above-formed ion sieve and immersing it in 20 ml of a lithium solution with a lithium concentration of 50 ppm (the lithium solution is prepared by lithium hydroxide monohydrate), and vibrating it in a constant temperature vibration box at room temperature at a speed of 100 rpm for 24 h to obtain an ion sieve after Li adsorption and a solution after de-lithiation;

[0180] (7) Desorbing the ion sieve after adsorbing Li with a 0.6 mol / L hydrochloric acid solution as an eluent to obtain a desorbed solution, wherein the liquid-to-solid mass ratio is controlled at 500:1 and the time is controlled at 12 h;

[0181] (8) ICP-OES was used to test the concentration of Mn ions in the solution after desorption and the concentration of Li in the solution after delithiation. The lithium extraction rate was calculated to be 98.1% and the manganese loss rate was 1.5%.

[0182] Comparative Example 1

[0183] 0.1g of lithium ion sieve adsorbent material MnO2·0.5H2O was placed in 20ml 0.05mol / L -1 The lithium-containing solution (prepared from lithium hydroxide monohydrate) was shaken in a constant temperature oscillating box at 25°C at a speed of 100 rpm for 24 h to ensure that the adsorption reached equilibrium and obtain the lithium ion sieve precursor Li 1.6 Mn 1.6 O4, take the supernatant to determine the ion concentration in the solution (solution after delithiation). 1.6 Mn 1.6 O4 was vacuum filtered, washed with deionized water until neutral, and dried in an oven. 1.6 Mn 1.6 O4 ion sieve precursor powder was added to 20 mL of 0.5 mol L -1 The mixture was placed in a hydrochloric acid solution and shaken at 100 rpm for 24 hours at 25°C in a constant temperature shaking box to remove lithium ions (desorption solution). The concentration of Mn ions in the desorption solution and the concentration of Li in the delithiation solution were tested by ICP-OES. The lithium extraction rate was calculated to be 91.3% and the manganese loss rate was 11.5%.

[0184] Comparative Example 2

[0185] (1) dissolving agar and 0.5 g of polyvinyl chloride in a mass ratio of 20% (the proportion of agar in polyvinyl chloride) in 8.7 mL of N,N'-dimethylformamide and stirring continuously to obtain a homogeneous solution which is used as a binder solution;

[0186] (2) 2 g Li 1.6 Mn 1.6 The O4 ion sieve powder was stirred and mixed with the above binder solution, and the stirring was continued at 100 r / min for 24 h to obtain a black slurry;

[0187] (3) dropping the black slurry into deionized water at a flow rate of 2 mL / min to form a shape;

[0188] (4) soaking the molded ion sieve obtained in the above process in 0.1 mol / L hydrochloric acid for 24 hours to obtain manganese-based lithium ion sieve spherical particles;

[0189] (5) washing the formed ion sieve obtained in the above process with deionized water and drying it to obtain an adsorbent product to be used;

[0190] (6) taking 0.5 g of the above-formed ion sieve and immersing it in 20 ml of a lithium solution with a lithium concentration of 50 ppm (the lithium solution is prepared by lithium hydroxide monohydrate), and vibrating it in a constant temperature vibration box at room temperature at a speed of 100 rpm for 24 h to obtain an ion sieve after Li adsorption and a solution after de-lithiation;

[0191] (7) using an aqueous solution of ammonium persulfate as an eluent to desorb the ion sieve after adsorbing Li to obtain a desorbed solution, wherein the concentration of the eluent is controlled at 0.3 mol / L, the liquid-to-solid mass ratio is controlled at 500:1, and the desorption time is controlled at 12 h;

[0192] (8) ICP-OES was used to test the concentration of Mn ions in the solution after desorption and the concentration of Li in the solution after delithiation. The lithium extraction rate was calculated to be 92.5% and the manganese loss rate was 9.7%.

[0193] Comparative Example 3

[0194] (1) 0.5 g of manganese-based lithium ion sieve adsorbent obtained from a project site was immersed in 20 ml of a lithium solution with a lithium concentration of 50 ppm and vibrated at 100 rpm in a constant temperature vibration box for 24 h at room temperature;

[0195] (2) Using 0.6 M HCl as the eluent, the liquid-to-solid ratio was controlled at 500:1, and the time was controlled at 12 h;

[0196] (3) The concentration of Mn ions in the solution after desorption and the concentration of Li in the solution after delithiation were tested by ICP-OES. The lithium extraction rate was calculated to be 75% and the manganese loss rate was 10.3%.

[0197] Table 1 Comparison of lithium extraction rate and manganese loss rate under different conditions

[0198] name Lithium extraction rate (%) Manganese loss rate (%) Example 1 98.1 0.05 Example 2 95.3 0.03 Example 3 94.1 0.1 Example 4 98.1 1.5 Comparative Example 1 91.3 11.5 Comparative Example 2 92.5 9.7 Comparative Example 3 75 10.3

[0199] It can be seen from the data in Table 1 that the lithium ion sieve adsorbent of the present application introduces a nitrogen-doped carbon-based transition metal single atom catalyst, which has a high lithium extraction rate when used to adsorb and separate lithium ions; and, during the desorption and regeneration process, using persulfate as an eluent can effectively inhibit the occurrence of manganese element sieve dissolution, and the manganese loss rate is significantly reduced.

[0200] In the description of the present application, it should be noted that the terms "upper", "lower", "inside", "outside", "front", "back", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships in the working state of the present application. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present application.

[0201] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "install", "connect" and "connect" should be understood in a broad sense. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0202] The present application has been described above in conjunction with preferred embodiments, but these embodiments are only exemplary and serve only as an illustration. On this basis, various replacements and improvements may be made to the present application, all of which fall within the scope of protection of the present application.

Claims

1. A lithium ion sieve adsorbent, characterized in that: The invention comprises the following components in proportion by mass based on the total mass of the lithium ion sieve adsorbent: Lithium ion sieve 50~90%, Single atom catalyst 1~20%, and auxiliary agents, the auxiliary agents comprising a binder and optional additives; Wherein, the lithium ion sieve is selected from a manganese-based lithium ion sieve, and the single-atom catalyst is selected from a nitrogen-doped carbon-based transition metal single-atom catalyst.

2. The lithium ion sieve adsorbent according to claim 1, characterized in that: The manganese-based lithium ion is selected from H 1.6 Mn 1.6 O4, HMn2O4, H4Mn5O 12 and H 1.33 Mn 1.67 A combination of one or more of O4.

3. The lithium ion sieve adsorbent according to claim 1 or 2, characterized in that: The nitrogen-doped carbon-based transition metal single-atom catalyst is selected from a combination of one or more of NC / Co, NC / Ni and NC / Mn.

4. The lithium ion sieve adsorbent according to claim 1 or 2, characterized in that: The binder is selected from one or more combinations of polyvinyl chloride, polyvinylidene fluoride, styrene-butadiene rubber and carboxymethyl cellulose.

5. The lithium ion sieve adsorbent according to claim 1 or 2, characterized in that: The additive is selected from one or more combinations of polyacrylonitrile, chitosan, cellulose, sodium alginate, agar and polyacrylamide.

6. The lithium ion sieve adsorbent according to claim 1 or 2, characterized in that: The mass ratio of the binder to the additive is (2-10): 1; and / or, The lithium ion sieve adsorbent includes the following components in proportion by mass based on the total mass of the lithium ion sieve adsorbent: Lithium ion sieve 60~80%, Single atom catalyst 2~7%, Binder 10-30%, Additives 2-7%.

7. The method for preparing the lithium ion sieve adsorbent according to any one of claims 1 to 6, characterized in that: The preparation method comprises the following steps: (1) dissolving a binder and optional additives in an organic solvent to obtain a binder solution; (2) dispersing a lithium ion sieve precursor and a single atom catalyst in the binder solution to obtain a slurry; Wherein, the lithium ion sieve precursor is selected from a manganese-based lithium ion sieve precursor, and the single atom catalyst is selected from a nitrogen-doped carbon-based transition metal single atom catalyst; (3) dropping the slurry into water to form it, and then soaking it in an acid solution to remove lithium, thereby obtaining the lithium ion sieve adsorbent.

8. The preparation method according to claim 7, characterized in that: The manganese-based lithium ion sieve precursor is selected from Li 1.6 Mn 1.6 O4, LiMn2O4, Li4Mn5O 12 and Li 1.33 Mn 1.67 A combination of one or more of O4.

9. The preparation method according to claim 7, characterized in that: In step (1): The ratio of the total mass of the binder and the additive to the volume of the organic solvent is 1 g: 10 to 20 mL; The organic solvent is selected from one or more combinations of N,N'-dimethylformamide, propylene glycol, dimethylformamide, isopropyl acetate, dimethyl sulfoxide and N-methylpyrrolidone; and / or, In step (2): The mass of the single atom catalyst accounts for 0.1-10% of the mass of the lithium ion sieve precursor. The ratio of the total mass of the lithium ion sieve precursor and the single atom catalyst to the volume of the binder solution is 1 g: 2 to 6 mL; and / or, In step (3): The slurry is dripped into the water at a speed of 1 to 10 mL / min. The acid solution is a 0.01-5 mol / L hydrochloric acid solution, The soaking time is 1 to 72 hours; Step (3) also includes cleaning and drying after immersion in the acid solution for lithium removal. The drying temperature is 200° C. or lower.

10. A lithium ion sieve adsorbent product, characterized in that: It comprises a lithium ion sieve adsorbent and an eluent; the lithium ion sieve adsorbent is selected from the lithium ion sieve adsorbent according to any one of claims 1 to 6 or is prepared by the preparation method according to any one of claims 7 to 9; the eluent is selected from persulfate; The eluent is preferably self-contained S2O8 2- and salts of inorganic cations; The eluent is further preferably selected from a combination of one or more of Na2S2O8, K2S2O8 and (NH4)2S2O8.

11. A lithium ion adsorption and separation method for inhibiting the dissolution loss of a manganese-based lithium ion sieve, characterized in that: The steps include: (S1) contacting a lithium ion-containing solution with the lithium ion sieve adsorbent according to any one of claims 1 to 6, or with the lithium ion sieve adsorbent prepared by the preparation method according to any one of claims 7 to 9, to obtain a lithium ion sieve adsorbent after lithium adsorption and a solution after lithium desorption; (S2) contacting the lithium ion sieve adsorbent after adsorbing lithium with an aqueous solution of an eluent to obtain a regenerated lithium ion sieve adsorbent; Wherein, the eluent is selected from persulfate, preferably from S2O8 2- and a salt of an inorganic cation, and further preferably a combination of one or more selected from Na2S2O8, K2S2O8 and (NH4)2S2O8.

12. The lithium ion adsorption separation method according to claim 11, characterized in that: In step (S2), the concentration of the aqueous solution of the eluent is 0.05-2 mol / L, preferably 0.1-0.5 mol / L; and / or, The liquid-to-solid mass ratio of the aqueous solution of the eluent to the lithium ion sieve adsorbent after lithium adsorption is (50-1000):1, preferably (100-900):1; The contact time between the lithium ion sieve adsorbent after lithium adsorption and the aqueous solution of the eluent is 1 to 72 hours.

Images