A lithium-ion sieve adsorbent and its preparation method, a lithium-ion sieve adsorbent product, and a lithium-ion adsorption and separation method.

Abstract

This invention relates to a lithium-ion sieve adsorbent and its preparation method, a lithium-ion sieve adsorbent product, and a lithium-ion adsorption and separation method. The lithium-ion sieve adsorbent comprises: 50-90% lithium-ion sieve, 1-20% single-atom catalyst, and additives, including binders and optional additives. 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. The lithium-ion sieve adsorbent of this invention has excellent lithium-ion adsorption and separation capabilities, achieving a high lithium extraction rate. The lithium-ion sieve adsorbent of this invention, combined with a persulfate eluent for lithium enrichment followed by desorption and regeneration, synergistically enhances the suppression of dissolution loss of the manganese-based lithium-ion sieve during desorption or regeneration, while simultaneously achieving a low manganese loss rate and efficient lithium-ion desorption. The lithium-ion adsorption and separation method for suppressing dissolution loss of the manganese-based lithium-ion sieve provided by this invention is simple, efficient, and effective, and can be well applied in industrial production.

Description

Technical Field

[0001] This invention relates to the field of metal resource utilization, specifically to a lithium-ion sieve adsorbent and its preparation method, lithium-ion sieve adsorbent products, and lithium-ion adsorption and separation methods. Background Technology

[0002] Global lithium resources exist in various types of solid ores, clays, lithium zeolites, salt lake brines, seawater, geothermal brines, and oil and gas field brines. Comparatively, brines constitute a larger proportion of onshore lithium reserves, and mining technologies are constantly evolving, thus holding enormous potential for lithium extraction.

[0003] Common lithium extraction technologies from brine resources include the salt gradient solar pool method, adsorption + membrane coupling method, and transmembrane processes such as microfiltration, nanofiltration, reverse osmosis, and electrodialysis. The solar pool method utilizes the negative temperature effect of lithium carbonate to concentrate lithium ions in carbonated brine. This process is not only limited by climate conditions, but the lithium-rich solution after solar pool concentration also requires subsequent purification. Adsorption and membrane coupling technology is currently the most industrialized process, highly suitable for brine resources with low lithium ion concentrations, enabling selective enrichment of lithium ions in low-grade brine. Currently, lithium-ion sieve adsorbents are mainly divided into three categories: aluminum-based lithium-ion sieves, titanium-based lithium-ion sieves, and manganese-based lithium-ion sieves. Among them, manganese-based lithium-ion sieves have high adsorption capacity and are considered one of the most promising lithium-ion sieve adsorbents. However, the bottleneck limiting the industrial application of manganese-based lithium-ion sieve adsorbents lies in the fact that due to the inherent properties of manganese, a disproportionation reaction of manganese centers occurs during the elution process, leading to severe dissolution of the adsorbent. The adsorbent's failure also introduces manganese ion impurities into the subsequent purification of lithium ions.

[0004] Currently, researchers (CN 108622942A, CN 110773112A) mainly improve the dissolution problem of manganese-based lithium-ion sieves through doping. Specific methods include grinding, solid-state sintering, and sol-gel methods. The core objective is to replace some of the low-valence manganese by doping, thereby increasing the average valence of manganese. This process not only involves the stringent environmental conditions required for heteroatom doping of crystals but also may introduce new impurity elements. Therefore, 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 powdered lithium-ion sieves. However, the active sites of ion sieves with larger exposed surfaces still suffer from severe manganese dissolution. Patent CN 116328713A discloses a method for preparing lithium-ion sieve adsorbent particles and its application. This invention provides an improvement to the stability of ion sieves through an improved method of granulating powdered ion sieves. 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 low-cost method for preparing a layered lithium ion sieve, specifically using solid waste residue as raw material to prepare a high-performance lithium ion sieve, thereby reducing raw material costs. Analysis of the published patents reveals that researchers primarily focus on improving the stability of the ion sieve from the perspectives of molding and preparation processes, while the eluent still uses dilute acid, resulting in insufficient improvement in the dissolution loss of the ion sieve during the desorption process.

[0005] The severe manganese loss and limited cycle life of manganese-based lithium ion sieves during the desorption stage after lithium ion enrichment in solution are problems that urgently need to be solved. How to obtain a lithium ion sieve adsorbent with high lithium extraction rate and how to avoid or effectively reduce the sieve loss phenomenon during the desorption stage are problems that urgently need to be solved. Summary of the Invention

[0006] This invention provides a lithium-ion sieve adsorbent and its preparation method, a lithium-ion sieve adsorbent product, and a lithium-ion adsorption and separation method. The purpose is to provide a lithium-ion sieve adsorbent with a high lithium extraction rate, avoid or reduce the dissolution loss of manganese-based lithium-ion sieve adsorbents during the desorption stage, and achieve a low manganese loss rate.

[0007] In a first aspect, the present invention relates to a lithium-ion sieve adsorbent, comprising components in the following mass percentages 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 additives, including binders and optional additives;

[0011] The lithium ions are screened from manganese-based lithium ion sieves, and the single-atom catalyst is selected from nitrogen-doped carbon-based transition metal single-atom catalysts.

[0012] Optionally, the manganese-based lithium ions are screened from H 1.6 Mn 1.6 O4, HMn2O4, H4Mn5O 12 and H 1.33 Mn 1.67 One or more combinations of O4.

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

[0014] Optionally, the adhesive 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 adhesive to the additive is (2~10):1; and / or,

[0017] The lithium-ion sieve adsorbent comprises the following components in the following mass percentages based on the total mass of the lithium-ion sieve adsorbent:

[0018] Lithium ion sieve 60~80%,

[0019] Single-atom catalysts 2-7%,

[0020] Adhesive 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 method comprising the following steps:

[0023] (1) Dissolve the adhesive and optional additives in an organic solvent to obtain an adhesive solution;

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

[0025] The lithium-ion sieve precursor is selected from manganese-based lithium-ion sieve precursors, and the single-atom catalyst is selected from nitrogen-doped carbon-based transition metal single-atom catalysts.

[0026] (3) The slurry is dripped into water to form a solid, and then soaked 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 One or more combinations 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 1g:10~20mL;

[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 percentage of the single-atom catalyst in the mass of the lithium-ion sieve precursor is 0.1% to 10%.

[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: 2~6 mL; and / or,

[0034] In step (3):

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

[0036] The acid solution is a 0.01~5 mol / L hydrochloric acid solution.

[0037] The soaking time is 1~72 h;

[0038] Step (3) also includes the washing and drying following the lithium removal process by immersion in the acid solution.

[0039] The drying temperature is below 200°C.

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

[0041] The eluent is preferably composed of S2O8. 2- Salts of inorganic cations;

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

[0043] Fourthly, the present invention relates to a lithium-ion adsorption and separation method for suppressing dissolution loss by manganese-based lithium-ion sieves, comprising the following steps:

[0044] (S1) Contact the lithium-ion-containing solution with the lithium-ion sieve adsorbent described in the first aspect, or with 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 removal.

[0045] (S2) The lithium-ion sieve adsorbent after lithium adsorption is contacted with an aqueous solution of eluent to obtain a regenerated lithium-ion sieve adsorbent.

[0046] The eluent is selected from persulfate, preferably from a compound containing S2O8. 2- Salts of inorganic cations, further preferably a combination of one or more of 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-solid mass ratio of the aqueous 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 1~72 h.

[0051] Beneficial effects:

[0052] The lithium-ion sieve adsorbent provided by this invention has excellent lithium-ion adsorption and separation capabilities, achieving a high lithium extraction rate. The lithium-ion sieve adsorbent of this invention, combined with a persulfate eluent for lithium enrichment followed by desorption and regeneration, synergistically enhances the suppression of dissolution loss of the manganese-based lithium-ion sieve during desorption or regeneration, while simultaneously achieving a low manganese loss rate and efficient lithium-ion desorption. The lithium-ion adsorption and separation method for suppressing dissolution loss of the manganese-based lithium-ion sieve provided by this invention is simple, efficient, and highly effective, and can be well applied in industrial production. Detailed Implementation

[0053] The present application will be further described in detail below through embodiments. Through these descriptions, the features and advantages of the present application will become clearer and more apparent.

[0054] The term “exemplary” as used herein means “serving as an example, embodiment, or illustration.” Any embodiment illustrated herein as “exemplary” is not necessarily to be construed as superior to or better than other embodiments.

[0055] Furthermore, the technical features involved in the different embodiments of this 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 components in the following mass percentages 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 additives, including binders and optional additives;

[0060] The lithium ions are screened from manganese-based lithium ion sieves, and the single-atom catalyst is selected from nitrogen-doped carbon-based transition metal single-atom catalysts.

[0061] It should be noted that the lithium-ion sieve adsorbent of the present invention innovatively introduces a single-atom catalyst, which enables the lithium-ion sieve adsorbent to 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 solutions; and the lithium-ion sieve adsorbent containing the above-mentioned single-atom catalyst can effectively suppress the sieve dissolution phenomenon of manganese-based lithium-ion sieves during the delithiation stage when it is contacted with an eluent solution containing persulfate for delithiation and regeneration, while achieving a low manganese loss rate.

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

[0063] According to a specific embodiment of the lithium-ion sieve adsorbent of 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 One or more combinations of O4.

[0064] It should be noted that the lithium-ion sieve adsorbent formed by combining one or more of the above-mentioned manganese-based lithium-ion sieves with single-atom catalysts and additives can achieve better synergistic effects with the manganese-based lithium-ion sieves, single-atom catalysts and additives, thereby further improving the lithium adsorption and separation effect of the lithium-ion sieve adsorbent. Furthermore, when it comes into contact with an eluent solution containing persulfate for delithiation and regeneration, it can further reduce the manganese loss rate, that is, better suppress the sieve dissolution loss during the delithiation process.

[0065] According to a specific embodiment of the lithium-ion sieve adsorbent of the first aspect of the present invention, the nitrogen-doped carbon-based transition metal single-atom catalyst is selected from one or more combinations 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. Catalysts that can efficiently catalyze the conversion of persulfate ions in eluents or desorbents into sulfate radicals are all within the scope of this application.

[0067] It should be noted that using one or more combinations of the above-mentioned NC / Co, NC / Ni, and NC / Mn as a single-atom catalyst with H 1.6 Mn 1.6 O4, HMn2O4, H4Mn5O 12 and H 1.33 Mn 1.67 When one or more of the O4 phases are combined, the lithium extraction rate of the resulting lithium-ion sieve adsorbent is further improved, and the manganese loss rate is further reduced when it is regenerated by contacting an eluent solution containing persulfate.

[0068] It should be noted that the above-mentioned NC / Co, NC / Ni, and NC / Mn can be prepared using commercially available 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 stirred thoroughly. Then, Co salt, Ni salt, or Mn salt can be added and stirred thoroughly 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 one or more combinations 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 one or more combinations of polyacrylonitrile, chitosan, cellulose, sodium alginate, agar and polyacrylamide.

[0071] It should be noted that the use of the above-mentioned binders and additives gives the lithium-ion sieve adsorbent of this application excellent stability, enabling it to 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 comprises the following components in the following mass percentages based on the total mass of the lithium-ion sieve adsorbent:

[0074] Lithium ion sieve 60~80%,

[0075] Single-atom catalysts 2-7%,

[0076] Adhesive 10~30%,

[0077] Additives 2-7%.

[0078] It should be noted that, as a preferred embodiment, by controlling the mass ratio of binder and additive as described above, and / or by controlling the mass percentage of lithium ion sieve, single-atom catalyst, binder and additive in the lithium ion sieve adsorbent as described above, the lithium adsorption and separation effect of the resulting 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 delithiation and regeneration, the manganese loss rate can be further reduced, that is, the sieve dissolution loss during the delithiation 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 method comprising the following steps:

[0080] (1) Dissolve the adhesive and optional additives in an organic solvent to obtain an adhesive solution;

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

[0082] The lithium-ion sieve precursor is selected from manganese-based lithium-ion sieve precursors, and the single-atom catalyst is selected from nitrogen-doped carbon-based transition metal single-atom catalysts.

[0083] (3) The slurry is dripped into water to form a solid, and then soaked 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 and LiMn2O4 are converted into lithium-ion sieves H after being soaked and delithiated in step (3). 1.6 Mn 1.6 O4, HMn2O4. During the preparation of lithium-ion sieve adsorbents, the single-atom catalyst is retained in the prepared lithium-ion sieve adsorbent. Lithium-ion sieve precursors such as Li 1.6 Mn 1.6 O4 and LiMn2O4 are converted into lithium ion sieves H. 1.6 Mn 1.6 O4, HMn2O4, and the additives remain essentially 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 incorporates the single-atom catalyst during the granulation process, so that the single-atom catalyst is uniformly dispersed in the shaped lithium-ion sieve adsorbent; the lithium-ion sieve adsorbent prepared by introducing the single-atom catalyst has a good lithium-ion adsorption and separation capacity, and can effectively avoid or significantly reduce the occurrence of manganese dissolution during the process of delithiation and adsorbent regeneration using persulfate as an eluent.

[0085] It should be noted that in step (3), a reverse solvent conversion method is used to drop black slurry into deionized water to form spheres, and then the lithium ion sieve is pre-delithiated by soaking in an acid solution. The lithium ion sieve adsorbent prepared by the method of this application can effectively introduce single-atom catalysts, and the lithium ion sieves converted from single-atom catalysts and lithium ion sieve precursors are uniformly and stably distributed in the spherical lithium ion sieve adsorbent. The prepared lithium ion sieve adsorbent has a good lithium ion adsorption and separation capacity, and can effectively suppress manganese loss during the delithiation and regeneration process using persulfate as an eluent, while also achieving 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 One or more combinations of O4.

[0087] It should be noted that in the preparation method of the present invention, after soaking in the acid solution in step (3), the above-mentioned manganese-based lithium ion sieve precursor Li 1.6 Mn 1.6 O4, LiMn2O4, Li4Mn5O 12 and Li 1.33 Mn 1.67 O4 is then 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; Based on this manganese-based lithium ion sieve, the lithium ion sieve adsorbent obtained by combining it with the above-mentioned single-atom catalyst and auxiliary agent has a synergistic effect among the components, which further improves the lithium adsorption and separation effect of the lithium ion sieve adsorbent. Furthermore, when it is contacted with the eluent solution containing persulfate for delithiation and regeneration, it can further reduce the manganese loss rate, that is, better suppress the sieve dissolution loss in the delithiation process.

[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 1g:10~20mL;

[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 percentage of the single-atom catalyst in the mass of the lithium-ion sieve precursor is 0.1% to 10%.

[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: 2~6 mL; and / or,

[0094] In step (3):

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

[0096] The acid solution is a 0.01~5 mol / L hydrochloric acid solution.

[0097] The soaking time is 1~72 h;

[0098] Step (3) also includes the washing and drying following the lithium removal process by immersion in the acid solution.

[0099] The drying temperature is below 200°C.

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

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

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

[0103] The eluent is preferably composed of S2O8. 2- Salts of inorganic cations;

[0104] The eluent is further preferably 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 aforementioned 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 aforementioned single-atom catalyst, the desorption solution containing the eluent can generate hydrogen ions and sulfate radicals under mild catalytic conditions. The generated hydrogen ions can displace the lithium ions adsorbed in the lithium-ion sieve adsorbent, thereby regenerating the adsorbent. The generated sulfate radicals can effectively inhibit the dissolution and loss of manganese. When the eluent is selected from one or more combinations of Na2S2O8, K2S2O8, and (NH4)2S2O8, it can further reduce the manganese loss rate during desorption while maintaining a high lithium extraction rate.

[0106] Fourthly, the present invention relates to a lithium-ion adsorption and separation method for suppressing dissolution loss by manganese-based lithium-ion sieves, comprising the following steps:

[0107] (S1) Contact the lithium-ion-containing solution with the lithium-ion sieve adsorbent described in the first aspect, or with 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 removal.

[0108] (S2) The lithium-ion sieve adsorbent after lithium adsorption is contacted with an aqueous solution of eluent to obtain a regenerated lithium-ion sieve adsorbent.

[0109] The eluent is selected from persulfate, preferably from a compound containing S2O8. 2- Salts of inorganic cations, further preferably a combination of one or more of Na2S2O8, K2S2O8 and (NH4)2S2O8.

[0110] It should be noted that the dissolution process of manganese-based lithium ion sieves is suppressed by introducing the aforementioned nitrogen-doped carbon-based transition metal single-atom catalyst and adapting it with a highly efficient eluent during the molding process of manganese-based lithium ion sieves. This invention utilizes a catalyst doped into the adsorbent of manganese-based lithium ion sieves, combined with a persulfate eluent (desorption solution). During the elution process of lithium ion sieves after lithium ion adsorption, persulfate decomposes to generate hydrogen ions that replace lithium ions (lithium ions adsorbed in the manganese-based lithium ion sieve). Simultaneously, the single-atom catalyst catalyzes the persulfate ions to generate sulfate radicals, which act as electron acceptors. These sulfate radicals can then accept electrons generated by unstable Mn(III), thereby promoting the conversion of Mn(III) into the more stable Mn(IV), suppressing the Mn(III) disproportionation process, effectively inhibiting the dissolution of manganese-based lithium ion sieves, and simultaneously achieving highly efficient lithium desorption from the manganese-based lithium ion sieve.

[0111] It should be noted that after the lithium-ion sieve adsorbent adsorbs adsorbent adsorbed with lithium is contacted with an aqueous solution of eluent, a regenerated lithium-ion sieve adsorbent can be obtained. For example, the lithium-ion sieve adsorbent adsorbed with lithium may contain Li. 1.6 Mn 1.6 O4 and LiMn2O4 are converted into H after regeneration by contact with the eluent. 1.6 Mn 1.6 O4, HMn2O4. Lithium ions and sulfate radicals remain in the eluent aqueous solution (the desorbed solution), and the lithium ions obtained can be converted into lithium carbonate precipitate by sodium carbonate precipitation.

[0112] In existing technologies, during the lithium ion elution process of manganese-based lithium ion sieves, Mn(III) inevitably undergoes a disproportionation reaction, producing Mn(II) and Mn(IV). The main process is as follows: during acid elution, trace amounts of trivalent manganese ions in the internal phase are unstable and release an electron to maintain stability. This released electron freely transfers to tetravalent manganese ions in the surface phase. The tetravalent manganese ions, having captured enough electrons, decrease in valence to form divalent manganese ions, which dissolve in the eluent. This ultimately leads 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 sieve loss or dissolution of the lithium ion sieve. This invention addresses this issue by combining the design of the manganese-based lithium ion sieve with the appropriate eluent to suppress manganese dissolution while achieving efficient lithium ion desorption. Considering that the electron transfer of trivalent manganese triggers subsequent dissolution, this invention introduces free radicals as electron acceptors to avoid the appearance of easily soluble divalent manganese. Simultaneously, persulfate ions react with water to generate hydrogen ions, which are used to replace lithium ions in the lithium ion sieve. Therefore, in this invention, persulfate is used as an eluent to introduce a single-atom catalyst that catalyzes the generation of sulfate radicals from persulfate into the ion sieve during the granulation process of manganese-based lithium ion sieves, thereby achieving the suppression of manganese dissolution and efficient replacement of lithium ions during the elution process.

[0113] In summary, by introducing a catalyst and a persulfate eluent into the manganese-based lithium ion sieve in a clever combination, the hydrogen ions and sulfate radicals generated by the persulfate during the elution process are utilized to achieve efficient lithium elution and suppress manganese dissolution in the manganese-based lithium ion sieve.

[0114] According to a specific embodiment of the lithium-ion adsorption separation method of 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-solid mass ratio of the aqueous 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 1~72 h.

[0118] It should be noted that by controlling the concentration of the eluent aqueous solution, the liquid-solid mass ratio of the eluent aqueous solution and the lithium-ion sieve adsorbent after lithium adsorption, and the contact time between the lithium-ion sieve adsorbent after lithium adsorption and the eluent aqueous solution, the lithium-ion sieve adsorbent after lithium adsorption can better carry out the delithiation process, resulting in a fully regenerated lithium-ion sieve adsorbent. Furthermore, the sieve loss during the desorption process can be further suppressed, further reducing the manganese loss rate. The regenerated lithium-ion sieve adsorbent can be reused more effectively, thus extending its service life.

[0119] The present invention will be further described in detail below through examples, but these examples are not intended to limit the invention. 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, namely NC / Co catalyst, NC / Mn catalyst and NC / Ni catalyst, were prepared by the following preparation examples.

[0121] Example of lithium ion sieve preparation

[0122] 1. Li 1.6 Mn 1.6 O4 preparation example

[0123] First, a 0.5M lithium hydroxide solution was added to a high-pressure reactor, and Mn₂O₃ was added according to a certain lithium-manganese molar ratio (Li:Mn=1:1). After hydrothermal treatment at 250℃ for 15 hours, orthorhombic LiMnO₂ was obtained. Then, LiMnO₂ was calcined at 450℃ for 8 hours to obtain Li 1.6 Mn 1.6 O4.

[0124] 2. Li4Mn5O 12 Preparation Example

[0125] LiOH H2O and MnCO3 were weighed according to a lithium ion to manganese ion molar ratio of 1:1.23, deionized water was added, and the mixture was ball-milled and then vacuum dried to obtain the precursor. The precursor was placed in a tube furnace and sintered at 220℃ for 4 h in air atmosphere, followed by sintering at 420℃ for 8 h to obtain Li4Mn5O.12 .

[0126] 3. Li 1.33 Mn 1.67 O4 preparation example

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

[0128] Example of Nitrogen-Doped Carbon-Based Transition Metal Single-Atom Catalyst Preparation

[0129] 1. Example of NC / Co catalyst preparation

[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 oxalic acid-ethanol solution and stirred thoroughly for 12 h. Then, 0.2 g of cobalt chloride was added, and the mixture 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 then heat-treated at 950 °C for 1 h under a nitrogen atmosphere and allowed to cool naturally to room temperature to obtain NC / Co.

[0131] 2. Example of NC / Mn catalyst preparation

[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 oxalic acid-ethanol solution and stirred thoroughly for 12 h. Then, 0.3 g of manganese chloride was added, and the mixture 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 then heat-treated at 950 °C for 1 h under a nitrogen atmosphere and allowed to cool naturally to room temperature to obtain NC / Mn.

[0133] 3. Example of NC / Ni catalyst preparation

[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 oxalic acid-ethanol solution and stirred thoroughly for 12 h. Then, 0.3 g of nickel chloride was added, and the mixture 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 then heat-treated at 950 °C for 1 h under a nitrogen atmosphere and allowed to cool naturally to room temperature to obtain NC / Ni.

[0135] The following examples illustrate the method for calculating the lithium extraction rate:

[0136]

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

[0138] C1 represents the concentration of Li ions in the solution after delithiation, in g / L.

[0139] The method for calculating the manganese loss rate is as follows:

[0140]

[0141] C Mn V represents the concentration of manganese ions in the desorbed solution, in g / L; Vdesorbent represents the volume of the desorbed solution, in 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 (g / mol);

[0143] m represents the H content in the adsorbent product. 1.6 Mn 1.6 O4, H4Mn5O 12 、 or H 1.33 Mn 1.67 Mass of O4, g;

[0144] x is H 1.6 Mn 1.6 O4, H4Mn5O 12 、 or H 1.33 Mn 1.67 The percentage of 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) Dissolve agar and 0.5g of polyvinyl chloride in 8.7mL of N,N'-dimethylformamide at a mass ratio of 20% (the proportion of agar in polyvinyl chloride) and stir continuously to obtain a homogeneous solution, which is then used as an adhesive solution.

[0148] (2) Take 2g Li 1.6 Mn 1.6 After thoroughly mixing O4 ion sieve powder and 0.1g NC / Co catalyst powder, add them to the above binder solution and stir continuously at 100 r / min for 24h to obtain a black slurry.

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

[0150] (4) The shaped ion sieve obtained by the above process is soaked in 0.1 mol / L hydrochloric acid for 24 h to obtain manganese-based lithium ion sieve spherical particles doped with a high-efficiency catalyst.

[0151] (5) The shaped ion sieve obtained in the above process is washed with deionized water and then dried to obtain the adsorbent product to be used, wherein the lithium ion sieve powder content in the shaped ion sieve is about 74%;

[0152] (6) Take 0.5 g of the above-formed ion sieve and soak it in 20 ml of lithium solution with a lithium concentration of 50 ppm (the lithium solution is prepared by lithium hydroxide monohydrate). Vibrate it in a constant temperature shaking box at 100 rpm for 24 h at room temperature to obtain the ion sieve after adsorbing Li and the solution after delithiation.

[0153] (7) Using ammonium persulfate aqueous solution as eluent, the ion sieve after adsorbing Li was desorbed to obtain a desorbed solution. The concentration of eluent was controlled at 0.3 mol / L, the liquid-solid mass ratio was controlled at 500:1, and the time was controlled at 12 h.

[0154] (8) The concentration of Mn ions in the desorbed solution and the concentration of Li in the delithiated solution were tested by ICP-OES. 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 0.675g of carboxymethyl cellulose were dissolved in 12mL 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 then used as an adhesive solution.

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

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

[0159] (4) The shaped ion sieve obtained by the above process is soaked 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) The shaped ion sieve obtained in the above process is washed with deionized water and then dried to obtain the adsorbent product to be used, wherein the content of lithium ion sieve powder in the shaped ion sieve is 75%;

[0161] (6) Take 1 g of the above-formed ion sieve and soak it in 20 mL of lithium solution with a lithium concentration of 100 ppm (the lithium solution is prepared by lithium hydroxide monohydrate). Vibrate it in a constant temperature shaking box at 240 rpm for 30 h at room temperature to obtain the ion sieve after adsorbing Li and the solution after delithiation.

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

[0163] (8) The concentration of Mn ions in the desorbed solution and the concentration of Li in the delithiated solution were tested by ICP-OES. 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 0.5g 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 then used as an adhesive solution.

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

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

[0168] (4) The shaped ion sieve obtained by the above process is soaked in 0.5 mol / L hydrochloric acid for 7 h to obtain manganese-based lithium ion sieve spherical particles doped with a high-efficiency catalyst.

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

[0170] (6) Take 1 g of the above-formed ion sieve and soak it in 20 ml of lithium solution with a lithium concentration of 100 ppm (the lithium solution is prepared by lithium hydroxide monohydrate). Vibrate it in a constant temperature shaking box at 200 rpm for 30 h at room temperature to obtain the ion sieve after adsorbing Li and the solution after delithiation.

[0171] (7) Using sodium persulfate aqueous solution as eluent, the ion sieve after adsorbing Li was desorbed to obtain a desorbed solution. The concentration of eluent was controlled at 0.5 mol / L, the liquid-solid mass ratio was controlled at 600:1, and the time was controlled at 12 h.

[0172] (8) The concentration of Mn ions in the desorbed solution and the concentration of Li in the delithiated solution were tested by ICP-OES. The lithium extraction rate was calculated to be 94.1% and the manganese loss rate was 0.1%.

[0173] Example 4

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

[0175] (2) Take 2g Li 1.6 Mn 1.6 After thoroughly mixing O4 ion sieve powder and 0.1g NC / Co catalyst powder, add them to the above binder solution and stir continuously at 100 r / min for 24h to obtain a black slurry.

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

[0177] (4) The shaped ion sieve obtained by the above process is soaked in 0.1 mol / L hydrochloric acid for 24 h to obtain manganese-based lithium ion sieve spherical particles doped with a high-efficiency catalyst.

[0178] (5) The shaped ion sieve obtained in the above process is washed with deionized water and then dried to obtain the adsorbent product to be used, wherein the lithium ion sieve powder content in the shaped ion sieve is about 74%;

[0179] (6) Take 0.5 g of the above-formed ion sieve and soak it in 20 ml of lithium solution with a lithium concentration of 50 ppm (the lithium solution is prepared by lithium hydroxide monohydrate). Vibrate it in a constant temperature shaking box at 100 rpm for 24 h at room temperature to obtain the ion sieve after adsorbing Li and the solution after delithiation.

[0180] (7) The ion sieve after adsorbing Li was desorbed by using 0.6 mol / L hydrochloric acid solution as eluent to obtain a desorbed solution. The liquid-solid mass ratio was controlled at 500:1 and the time was controlled at 12 h.

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

[0182] Comparative Example 1

[0183] 0.1 g of lithium-ion sieve adsorbent material MnO2·0.5H2O was placed in 20 ml of 0.05 mol / L... -1 In a lithium-containing solution (prepared from lithium hydroxide monohydrate), the lithium-ion sieve precursor Li was obtained by shaking at 100 rpm for 24 h at 25°C in a constant-temperature shaking oven to ensure adsorption equilibrium. 1.6 Mn 1.6 O4 was used to determine the ion concentration in the supernatant solution (after delithiation). Subsequently, the precursor Li... 1.6 Mn 1.6 O4 was vacuum filtered, washed with deionized water until neutral, and then dried in an oven. Next, Li... 1.6 Mn 1.6 O4 ion sieve precursor powder was added to 20 mL of 0.5 mol / L solution. -1 The solution was in hydrochloric acid solution and shaken at 100 rpm in a constant temperature shaking chamber at 25°C for 24 h to desorb lithium ions (obtaining the desorbed solution). The concentration of Mn ions in the desorbed solution and the concentration of Li in the delithiated solution were measured 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) Dissolve agar and 0.5g of polyvinyl chloride in 8.7mL of N,N'-dimethylformamide at a mass ratio of 20% (the proportion of agar in polyvinyl chloride) and stir continuously to obtain a homogeneous solution, which is then used as an adhesive solution.

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

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

[0188] (4) The shaped ion sieve obtained by the above process is soaked in 0.1 mol / L hydrochloric acid for 24 h to obtain manganese-based lithium ion sieve spherical particles;

[0189] (5) The shaped ion sieve obtained in the above process is washed with deionized water and then dried to obtain the adsorbent product to be used.

[0190] (6) Take 0.5 g of the above-formed ion sieve and soak it in 20 ml of lithium solution with a lithium concentration of 50 ppm (the lithium solution is prepared by lithium hydroxide monohydrate). Vibrate it in a constant temperature shaking box at 100 rpm for 24 h at room temperature to obtain the ion sieve after adsorbing Li and the solution after delithiation.

[0191] (7) Using ammonium persulfate aqueous solution as eluent, the ion sieve after adsorbing Li was desorbed to obtain a desorbed solution. The concentration of eluent was controlled at 0.3 mol / L, the liquid-solid mass ratio was controlled at 500:1, and the time was controlled at 12 h.

[0192] (8) The concentration of Mn ions in the desorbed solution and the concentration of Li in the delithiated solution were tested by ICP-OES. The lithium extraction rate was calculated to be 92.5% and the manganese loss rate was 9.7%.

[0193] Comparative Example 3

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

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

[0196] (3) The concentration of Mn ions in the desorbed solution and the concentration of Li in the delithiation solution 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]

[0199] As can be seen from the data in Table 1, the lithium-ion sieve adsorbent of this application introduces a nitrogen-doped carbon-based transition metal single-atom catalyst, which has a high lithium extraction rate when used for adsorption and separation of lithium ions; and, in the desorption and regeneration process, the use of persulfate as an eluent can effectively inhibit the dissolution of manganese sieve, and the manganese loss rate is significantly reduced.

[0200] In the description of this application, it should be noted that the terms "upper", "lower", "inner", "outer", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship in the working state of this application. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0201] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0202] The present application has been described above with reference to preferred embodiments; however, these embodiments are merely exemplary and illustrative. Various substitutions and modifications can be made to the present application based on these embodiments, all of which fall within the protection scope of the present application.

Claims

1. A lithium-ion sieve adsorbent, characterized in that, Includes the following components by mass percentage based on the total mass of the lithium-ion sieve adsorbent: Lithium ion sieve 50~90%, Single-atom catalyst 1~20%, And additives, including binders and optional additives; The lithium ion screen is selected from manganese-based lithium ion screens, and the single-atom catalyst is selected from nitrogen-doped carbon-based transition metal single-atom catalysts. The nitrogen-doped carbon-based transition metal single-atom catalyst is selected from one or more combinations of NC / Co, NC / Ni, and NC / Mn.

2. The lithium-ion sieve adsorbent according to claim 1, characterized in that, The manganese-based lithium ions are screened from H 1.6 Mn 1.6 O4, HMn2O4, H4Mn5O 12 and H 1.33 Mn 1.67 One or more combinations of O4.

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

4. 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.

5. 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 comprises the following components in the following mass percentages based on the total mass of the lithium-ion sieve adsorbent: Lithium ion sieve 60~80%, Single-atom catalysts 2-7%, Adhesive 10~30%, Additives 2-7%.

6. The method for preparing the lithium-ion sieve adsorbent according to any one of claims 1-5, characterized in that, The preparation method includes the following steps: (1) Dissolve the adhesive and optional additives in an organic solvent to obtain an adhesive solution; (2) Disperse the lithium-ion sieve precursor and the single-atom catalyst in the binder solution to obtain a slurry; The lithium-ion sieve precursor is selected from manganese-based lithium-ion sieve precursors, and the single-atom catalyst is selected from nitrogen-doped carbon-based transition metal single-atom catalysts. (3) The slurry is dripped into water to form a solid, and then soaked in an acid solution to remove lithium, thereby obtaining the lithium ion sieve adsorbent.

7. The preparation method according to claim 6, 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 One or more combinations of O4.

8. The preparation method according to claim 6, 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 1g:10~20mL; 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 percentage of the single-atom catalyst in the mass of the lithium-ion sieve precursor is 0.1% to 10%. 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: 2~6 mL; and / or, In step (3): The slurry is dripped into the water at a rate of 1~10 mL / min. The acid solution is a 0.01~5 mol / L hydrochloric acid solution. The soaking time is 1~72 h; Step (3) also includes the washing and drying following the lithium removal process by immersion in the acid solution. The drying temperature is below 200°C.

9. A lithium-ion sieve adsorbent product, characterized in that, It includes a lithium-ion sieve adsorbent and an eluent; the lithium-ion sieve adsorbent is selected from the lithium-ion sieve adsorbent of any one of claims 1 to 5 or prepared by the preparation method of any one of claims 6 to 8; the eluent is selected from persulfate.

10. The lithium-ion sieve adsorbent product according to claim 9, characterized in that, The eluent is selected from those containing S2O8. 2- Salts of inorganic cations.

11. The lithium-ion sieve adsorbent product according to claim 10, characterized in that, The eluent is selected from one or more combinations of Na2S2O8, K2S2O8 and (NH4)2S2O8.

12. A lithium-ion adsorption and separation method for suppressing dissolution loss by manganese-based lithium-ion sieves, characterized in that, Includes the following steps: (S1) Contact the lithium-ion-containing solution with the lithium-ion sieve adsorbent according to any one of claims 1 to 5, or with the lithium-ion sieve adsorbent prepared by the preparation method according to any one of claims 6 to 8, to obtain the lithium-ion sieve adsorbent after lithium adsorption and the solution after lithium removal. (S2) The lithium-ion sieve adsorbent after lithium adsorption is contacted with an aqueous solution of eluent to obtain a regenerated lithium-ion sieve adsorbent. The eluent is selected from persulfate.

13. The lithium-ion adsorption separation method according to claim 12, characterized in that, The eluent is selected from those containing S2O8. 2- Salts of inorganic cations.

14. The lithium-ion adsorption separation method according to claim 13, characterized in that, The eluent is selected from one or more combinations of Na2S2O8, K2S2O8 and (NH4)2S2O8.

15. The lithium-ion adsorption separation method according to any one of claims 12-14, characterized in that, In step (S2), the concentration of the aqueous solution of the eluent is 0.05-2 mol / L; And / or, The liquid-solid mass ratio of the aqueous eluent to the lithium-ion sieve adsorbent after lithium adsorption is (50~1000):1; The contact time between the lithium-ion sieve adsorbent after lithium adsorption and the aqueous solution of the eluent is 1~72 h.

16. The lithium-ion adsorption separation method according to claim 15, characterized in that, The concentration of the aqueous solution of the eluent is 0.1-0.5 mol / L; And / or, The liquid-solid mass ratio of the aqueous solution of the eluent to the lithium-ion sieve adsorbent after lithium adsorption is (100~900):1.

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