Polyhydroxy chelating resin and preparation method thereof and boron removal method

Abstract

The present application relates to a polyhydroxy chelating resin and a preparation method thereof and a boron removal method. The preparation method of the polyhydroxy chelating resin comprises the following steps: subjecting an amino resin having a structure as shown in the general formula (I) and an aldose having a structure as shown in the general formula (II) to a nucleophilic addition reaction to prepare a Schiff base intermediate having a structure as shown in the general formula (III); subjecting the Schiff base intermediate and a reducing agent to a reduction reaction to prepare a polyhydroxy chelating resin having a structure as shown in the general formula (IV); wherein n is a positive integer; R is absent or is selected from substituted or unsubstituted C 1 ~C 9 The polyhydroxy chelating resin prepared in the present application exhibits excellent adsorption capacity and adsorption rate, and has a wide pH application range, and has a good boron removal effect under different pH conditions.

Description

Technical Field

[0001] The present application relates to the technical field of adsorption resins, and in particular to a polyhydroxy chelating resin and a preparation method thereof and a boron removal method. Background Art

[0002] With the increasing global attention to renewable energy and sustainable development, the demand for lithium-ion batteries has gradually increased. At the same time, the retirement of lithium batteries has triggered a huge demand for the effective recycling and resource reuse of waste batteries. In the recycling process of lithium batteries, a large amount of recycling liquid containing a variety of metal ions and impurities will be produced. Among them, boron, as an important trace element, although not a key component in the positive and negative electrode materials of the battery, may exist as an additive in the battery manufacturing process, or remain in the recycling liquid due to impure raw materials. Therefore, the lithium battery recycling liquid must be deboronized.

[0003] At present, the mainstream boron removal technology is adsorption, which uses specially made boron removal adsorption resins to selectively capture boron ions from the solution under certain conditions to achieve efficient boron removal. However, the adsorption capacity of traditional boron removal adsorption resins is low, resulting in low boron removal efficiency. Summary of the invention

[0004] Based on this, it is necessary to provide a polyhydroxy chelating resin and a preparation method thereof and a boron removal method to solve the problem that the adsorption capacity of traditional boron removal adsorption resins is low, resulting in low boron removal efficiency.

[0005] The above-mentioned purpose of the present application is achieved through the following technical solutions:

[0006] In a first aspect of the present application, a method for preparing a polyhydroxy chelating resin is provided, comprising the following steps:

[0007] A Schiff base intermediate having a structure as shown in the general formula (III) is prepared by subjecting an amino resin having a structure as shown in the general formula (I) and an aldose having a structure as shown in the general formula (II) to a nucleophilic addition reaction;

[0008] The Schiff base intermediate and the reducing agent are subjected to a reduction reaction to prepare a polyhydroxy chelating resin having a structure as shown in the general formula (IV);

[0009] (I); (II);

[0010] (III); (IV);

[0011] Wherein, n is a positive integer;

[0012] R is absent or is selected from substituted or unsubstituted C1-C9 alkylene.

[0013] In one embodiment, R is absent or is selected from one or more of hydroxy substituted C1~C3 alkylene and alkoxy substituted C1~C3 alkylene.

[0014] In one embodiment, the aldose comprises one or more of glyceraldehyde, glucose, galactose, mannose, maltose, ribose, deoxyribose, threose, erythrose, lyxose, xylose, arabinose, talose, idose, gulose, altrose and allose.

[0015] In one embodiment, the reducing agent includes one or more of sodium borohydride, sodium cyanoborohydride and sodium triacetoxyborohydride.

[0016] In one embodiment, the reaction temperatures of the nucleophilic addition reaction and the reduction reaction are independently 0°C to 10°C.

[0017] In one embodiment, the mass ratio of the amino resin to the aldose is 1:(0.4-1.0).

[0018] In one embodiment, the reaction time of the nucleophilic addition reaction is 2h~6h.

[0019] In one embodiment, the mass ratio of the amino resin to the reducing agent is 1:(1-10).

[0020] In one embodiment, the reaction time of the reduction reaction is 8h~12h.

[0021] In one embodiment, the nitrogen content of the amino resin is 15 atm.% to 25 atm.%.

[0022] In one embodiment, the preparation method of the amino resin comprises Gabriel synthesis method.

[0023] In one embodiment, the preparation method of the amino resin comprises the following steps:

[0024] The precursor is prepared by subjecting chlorine balls and phthalimide salt to N-alkylation reaction;

[0025] The precursor is subjected to a decomposition reaction to prepare the amino resin.

[0026] In one embodiment, the reagent causing the precursor to undergo a decomposition reaction includes one or more of hydrazine and an inorganic base.

[0027] In a second aspect of the present application, a polyhydroxy chelate resin is provided, which is prepared by the method for preparing the polyhydroxy chelate resin as described above.

[0028] In one embodiment, the particle size of the polyhydroxy chelating resin is 0.3 mm to 1.1 mm.

[0029] In one embodiment, the hydroxyl content of the polyhydroxy chelating resin is 45% to 95%;

[0030] In one embodiment, in the boron-containing wastewater, B4O7 2- Under the conditions of a boron content of 371.61 ppm and an adsorption time of 10 h, the boron adsorption capacity of the polyhydroxy chelating resin is ≥28 mg / g.

[0031] In one embodiment, the porosity of the polyhydroxy chelating resin is 30% to 70%.

[0032] In a third aspect of the present application, a boron removal method is provided, comprising the following steps:

[0033] The boron-containing wastewater is treated by adsorption using the polyhydroxy chelating resin as described above.

[0034] This application has at least the following beneficial effects:

[0035] The present application synthesizes Schiff base intermediates by nucleophilic addition reaction between amino group (-NH2) in amino resin and aldehyde group (-CHO) in aldose; the imine bond (-N=CH-) of Schiff base intermediate is unstable and easy to fall off, so the imine bond is reduced by reducing agent to obtain stable polyhydroxy chelate resin; polyhydroxy chelate resin has two ortho hydroxyl groups, which can react with boron ions to form a stable six-membered ring chelate, thereby realizing the selective adsorption and separation of boron ions in a complex multi-element environment. Compared with N-methylglucose amine modified resin prepared by nucleophilic substitution reaction, the present application adopts reductive amination reaction to prepare polyhydroxy chelate resin, which not only has high yield, less by-products, and higher product purity, but also has high grafting rate of aldose on polyhydroxy chelate resin, so that the hydroxyl content is significantly improved, which means that the product contains more adsorption sites and coordination functional groups, and thus shows excellent adsorption capacity and adsorption rate. At the same time, the pH application range of polyhydroxy chelating resin is wide, and it has a good boron removal effect under different pH conditions. It is not only suitable for the boron removal treatment of lithium battery recovery liquid, but also suitable for the boron removal treatment of salt lake brine or other boron-containing wastewater. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions in the embodiments of the present application and to more completely understand the present application and its beneficial effects, the following is a brief introduction to the drawings required for the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application, and those skilled in the art can obtain other drawings based on these drawings without creative work.

[0037] Figure 1 The synthetic route of the amino resin of Example 1 is shown in FIG.

[0038] Figure 2 The synthetic route diagram of the polyhydroxy chelating resin of Example 1;

[0039] Figure 3 It is a physical diagram of the polyhydroxy chelating resin of Example 1;

[0040] Figure 4 It is the infrared spectrogram of the polyhydroxy chelating resin of Example 1. DETAILED DESCRIPTION

[0041] In order to facilitate the understanding of the present application, the present application is further described in detail below in conjunction with specific embodiments. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0043] In the present application, the meaning of "and / or" includes any and all combinations of one or more related listed items. "At least one" means more than one, such as one, two and more than two. "Multiple" or "several" means at least two, such as two, three, etc., and "multi-layer" means at least two layers, such as two layers, three layers, etc., unless otherwise clearly and specifically defined. In the description of the present application, "several" means at least one, such as one, two, etc., unless otherwise clearly and specifically defined.

[0044] When a numerical range is disclosed in this application, the above range is considered to be continuous and includes the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Further, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe features or characteristics, the ranges can be combined. In other words, unless otherwise indicated, all ranges disclosed in this application should be understood to include any and all subranges included therein.

[0045] Unless otherwise specified, all steps of the present application may be performed sequentially or randomly. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), which means that step (c) may be added to the method in any order. For example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0046] In this application, "above" or "below" includes the number itself. For example, "1 below" includes 1.

[0047] The temperature parameters in this application, unless otherwise specified, are allowed to be either constant temperature treatment or to vary within a certain temperature range. It should be understood that the constant temperature treatment allows the temperature to fluctuate within the accuracy range controlled by the instrument. Fluctuations within the range of ±5°C, ±4°C, ±3°C, ±2°C, and ±1°C are allowed.

[0048] In the present application, room temperature refers to indoor temperature, normal temperature or general temperature. Generally speaking, the range of room temperature can be any one of the following temperature intervals: 23°C ± 2°C, 25°C ± 5°C or 20°C ± 5°C.

[0049] the term

[0050] Unless otherwise specified or there is a contradiction, the terms and phrases used in this application have the following meanings:

[0051] In the present application, when a substituent with the same symbol appears multiple times, each substituent may be the same or different from each other. For example, when a general formula contains multiple R, R may be the same or different from each other.

[0052] "Substituted or unsubstituted" means that the defined group may be substituted or unsubstituted. When the defined group is substituted, it should be understood that the defined group may be substituted by one or more substituents acceptable in the art. Suitable substituents include but are not limited to: C1~C 30Alkyl, cycloalkyl containing 3 to 20 ring atoms, heterocyclic group containing 3 to 20 ring atoms, aryl containing 6 to 20 ring atoms, heteroaryl containing 5 to 20 ring atoms, silanyl, carbonyl, alkoxycarbonyl, aryloxycarbonyl, carbamoyl, haloformyl, formyl, amino (-N(R)2), cyano, isocyano, isocyanate, thiocyanate, isothiocyanate, hydroxyl, trifluoromethyl, nitro or halogen, and the above groups may be further substituted by substituents acceptable in the art; it is understandable that R in -N(R)2 is independently substituted by groups acceptable in the art, including but not limited to: H, C1~C6 alkyl, cycloalkyl containing 3 to 8 ring atoms, heterocyclic group containing 3 to 8 ring atoms, aryl containing 5 to 10 ring atoms or heteroaryl containing 5 to 10 ring atoms.

[0053] The "number of ring atoms" refers to the number of atoms constituting the ring itself of a structural compound (e.g., a monocyclic compound, a condensed ring compound, a cross-linked compound, a carbocyclic compound, a heterocyclic compound) in which atoms are bonded to form a ring. When the ring is substituted by a substituent, the atoms contained in the substituent are not included in the ring atoms. The "number of ring atoms" described below is the same unless otherwise specified. For example, the number of ring atoms of a benzene ring is 6, the number of ring atoms of a naphthalene ring is 10, and the number of ring atoms of a thienyl group is 5.

[0054] "Alkyl" refers to a monovalent residue formed by the loss of a hydrogen atom from a saturated hydrocarbon containing a primary (normal) carbon atom, a secondary carbon atom, a tertiary carbon atom, a quaternary carbon atom, or a combination thereof. Alkyl can represent a straight chain, branched and / or cyclic alkyl group. The carbon number of the alkyl group can be 1 to 50, 1 to 30, 1 to 20, 1 to 10 or 1 to 6. Phrases containing this term, for example, "C1 to C9 alkyl" refers to an alkyl group containing 1 to 9 carbon atoms, and each occurrence can be independently C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl or C9 alkyl. Suitable examples include, but are not limited to, methyl (Me, -CH3), ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 2-propyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, -CH(C H3)CH2CH3), 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH3)3), 1-pentyl (n-pentyl, -CH2CH2CH2CH2CH3), 2-pentyl (-CH(CH3)CH2CH2CH3), 3-pentyl (-CH(CH2CH3)2), 2-methyl-2-butyl (-C(CH3)2CH2CH3), 3-methyl-2-butyl (-CH(CH3)CH(CH3)2), 3-methyl-1-butyl (- CH2CH2CH(CH3)2), 2-methyl-1-butyl (-CH2CH(CH3)CH2CH3), 1-hexyl (-CH2CH2CH2CH2CH2CH3), 2-hexyl (-CH(CH3)CH2CH2CH2CH3), 3-hexyl (-CH(CH2CH3)(CH2CH2CH3)), 2-methyl-2-pentyl (-C(CH3)2CH2CH2CH3), 3-methyl-2-pentyl (-CH(CH3)CH( CH3)CH2CH3), 4-methyl-2-pentyl (-CH(CH3)CH2CH(CH3)2), 3-methyl-3-pentyl (-C(CH3)(CH2CH3)2), 2-methyl-3-pentyl (-CH(CH2CH3)CH(CH3)2), 2,3-dimethyl-2-butyl (-C(CH3)2CH(CH3)2), 3,3-dimethyl-2-butyl (-CH(CH3)C(CH3)3, octyl (-(CH2)7CH3).

[0055] "Alkylene" refers to a hydrocarbon group with two monovalent radical centers derived from an alkyl group by removing a hydrogen atom, which can be a saturated branched alkyl group or a saturated straight-chain alkyl group. For example, "C1-C9 alkylene" means that the alkyl portion contains 1 to 9 carbon atoms, and each occurrence can be independently C1 alkylene, C4 alkylene, C5 alkylene, C6 alkylene, C7 alkylene, C8 alkylene or C9 alkylene. Suitable examples include, but are not limited to, methylene (-CH2-), 1,1-ethyl (-CH(CH3)-), 1,2-ethyl (-CH2CH2-), 1,1-propyl (-CH(CH2CH3)-), 1,2-propyl (-CH2CH(CH3)-), 1,3-propyl (-CH2CH2CH2-) and 1,4-butyl (-CH2CH2CH2CH2-).

[0056] "Halogen" refers to F, Cl, Br or I.

[0057] "White ball" refers to styrene-divinylbenzene copolymer in styrene-based adsorption resin. The white ball is subjected to chloromethylation reaction to introduce -CH2Cl active groups into the adsorption resin. This styrene-based adsorption resin with -CH2Cl active groups is called "chlorine ball".

[0058] "Swelling" refers to the phenomenon that high molecular polymers, such as white balls, chlorine balls and amino resins, expand in volume after being immersed in solvents, which can make the molecular structure of the high molecular polymer loose.

[0059] The presence of boron not only affects the purity and recovery efficiency of metal ions in the subsequent refining process, but may also have a negative impact on the quality of the final product. In particular, for the production of high-purity battery-grade chemicals (such as nickel sulfate, lithium carbonate, etc.), the requirements for boron content are extremely strict. The reasons are: (1) Boron ions will hinder metal recovery. During the refining process, they may form complexes or precipitates with the target metal ions, interfere with the extraction, crystallization or electrodeposition processes, and reduce metal recovery rate and product purity. (2) In high-purity battery materials, even trace amounts of boron may lead to a decrease in electrochemical performance, such as increasing the impedance of electrode materials, reducing charge and discharge efficiency, shortening battery life, and even causing safety hazards. (3) The impurity content of high-purity battery-grade chemicals is strictly regulated. The upper limit of boron is usually at the ppm level, which is far lower than the ordinary industrial standard to ensure the high performance and long life of battery materials. In view of the above problems, the development of an efficient, economical and environmentally friendly boron removal technology has become a key technical link in the field of lithium battery recycling.

[0060] At present, the mainstream boron removal technology is adsorption method: using special ion exchange resin (i.e. adsorption resin), which has good selectivity and adsorption capacity for boron ions, can capture boron ions from the solution under certain conditions, and achieve efficient boron removal treatment. There are reports that chitosan was modified with 2-amino-1,3-propanediol to obtain a boron removal adsorption resin containing polyhydroxyl groups, but the regeneration time of this boron removal adsorption resin is long, and chitosan will have a certain loss during regeneration by acid washing, which is not conducive to the long-term recycling of the boron removal adsorption resin. There are reports that boron removal adsorption resins prepared with chlorine balls and N-methylglucamine as raw materials, but the adsorption capacity of this boron removal adsorption resin is low, and the adsorption effect is greatly affected by pH. Generally, it has a good boron removal effect under weak alkaline conditions, but the boron removal effect is poor under acidic conditions. Therefore, it is necessary to develop a boron removal adsorption resin with large adsorption capacity, wide pH application range, good recycling performance and easy synthesis.

[0061] Based on this, in the first aspect of the present application, a method for preparing a polyhydroxy chelating resin is provided.

[0062] In some embodiments, the method for preparing a polyhydroxy chelating resin comprises the following steps:

[0063] S100: subjecting an amino resin having a structure as shown in the general formula (I) and an aldose having a structure as shown in the general formula (II) to a nucleophilic addition reaction to prepare a Schiff base intermediate having a structure as shown in the general formula (III);

[0064] S200: subjecting the Schiff base intermediate and the reducing agent to a reduction reaction to prepare a polyhydroxy chelating resin having a structure as shown in the general formula (IV);

[0065] (I); (II);

[0066] (III); (IV);

[0067] Wherein, n is a positive integer;

[0068] R is absent or is selected from substituted or unsubstituted C1-C9 alkylene.

[0069] It can be understood that in the structures shown in Formula (I) to (IV), n is a positive integer, including but not limited to: 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 25, 30, 35, 40, 45, 50, 100, 200, 300, 400, 500 and 1000.

[0070] It can be understood that the nucleophilic addition reaction of aldehydes (or ketones) and amines generates a Schiff base intermediate containing an imine bond, which is then reduced by a reducing agent to obtain an amine compound. This reaction process is called "reductive amination reaction".

[0071] The present application synthesizes Schiff base intermediates by nucleophilic addition reaction between amino group (-NH2) in amino resin and aldehyde group (-CHO) in aldose; the imine bond (-N=CH-) of Schiff base intermediate is unstable and easy to fall off, so the imine bond is reduced by reducing agent to obtain stable polyhydroxy chelate resin; polyhydroxy chelate resin has two ortho hydroxyl groups, which can react with boron ions to form a stable six-membered ring chelate, thereby realizing the selective adsorption and separation of boron ions in a complex multi-element environment. Compared with N-methylglucose amine modified resin prepared by nucleophilic substitution reaction, the present application adopts reductive amination reaction to prepare polyhydroxy chelate resin, which not only has high yield, less by-products, and higher product purity, but also has high grafting rate of aldose on polyhydroxy chelate resin, so that the hydroxyl content is significantly improved, which means that the product contains more adsorption sites and coordination functional groups, and thus shows excellent adsorption capacity and adsorption rate. At the same time, the pH application range of polyhydroxy chelating resin is wide, and it has a good boron removal effect under different pH conditions. It is not only suitable for the boron removal treatment of lithium battery recovery liquid, but also suitable for the boron removal treatment of salt lake brine or other boron-containing wastewater.

[0072] In addition, the preparation method provided in the present application also has the advantages of simple operation steps and reaction conditions and temperature, which is conducive to reducing the cost of the polyhydroxy chelating resin and is suitable for large-scale industrial application.

[0073] The preparation method of the polyhydroxy chelate resin is described in detail below in a step-by-step manner.

[0074] S100: An amino resin and an aldose are subjected to a nucleophilic addition reaction to prepare a Schiff base intermediate.

[0075] Optionally, the nitrogen content of the amino resin is 15 atm.% to 25 atm.%. As an example, the nitrogen content of the amino resin may be 15 atm.%, 16 atm.%, 17 atm.%, 18 atm.%, 19 atm.%, 20 atm.%, 21 atm.%, 22 atm.%, 23 atm.%, 24 atm.% or 25 atm.%.

[0076] It can be understood that the atomic percentage of nitrogen in the amino resin is between 15% and 25%, which can ensure that there are enough amino groups on the amino resin to undergo nucleophilic addition reaction with aldose, thereby increasing the grafting rate of aldose on the resin and significantly improving the content of ortho-hydroxyl groups on the polyhydroxy chelating resin, thereby showing excellent adsorption capacity for boron ions.

[0077] Optionally, the preparation method of the amino resin comprises Gabriel synthesis method.

[0078] It can be understood that the Gabriel synthesis is a method for synthesizing primary amines, which utilizes the reaction of phthalimide salts with alkyl halides to generate N-alkylated phthalimide (i.e., precursor), which is then hydrolyzed under acidic or alkaline conditions to obtain primary amines and phthalic acid, or subjected to hydrazinolysis to obtain primary amines and phthaloyl hydrazide.

[0079] Optionally, the preparation method of the amino resin comprises the following steps:

[0080] S111: subjecting chlorine balls and phthalimide salt to N-alkylation reaction to prepare a precursor;

[0081] S112: causing the precursor to undergo a decomposition reaction to prepare an amino resin.

[0082] Optionally, the phthalimide salt includes one or more of sodium phthalimide and potassium phthalimide, and further optionally potassium phthalimide.

[0083] Optionally, the reaction temperature of the N-alkylation reaction is 80° C. to 120° C., and further optionally 80° C. to 100° C. As an example, the reaction temperature of the N-alkylation reaction may be 80° C., 85° C., 90° C., 95° C., 100° C., 105° C., 110° C., 115° C. or 120° C.

[0084] Optionally, the reaction time of the N-alkylation reaction is 6 h to 12 h, and further optionally 6 h to 9 h. As an example, the reaction time of the N-alkylation reaction can be 6 h, 7 h, 8 h, 9 h, 10 h, 11 h or 12 h.

[0085] Optionally, the N-alkylation reaction is carried out in a first solvent. It is understandable that the first solvent does not react with chlorine balls or phthalimide salts, and the amount of the first solvent used takes into account factors such as reaction time, reaction temperature, type of solvent, type of raw materials and reaction scale. Among them, the first solvent includes one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), methanol (MeOH) and ethanol (EtOH), and can further be N,N-dimethylformamide (DMF); the mass ratio of chlorine balls to the first solvent is 1: (1~5), and can further be 1: (3~5).

[0086] Optionally, the chlorine ball and the phthalimide salt are subjected to an N-alkylation reaction, comprising the following steps: mixing the chlorine ball and the first solvent, conducting a first swelling reaction, and adding the phthalimide salt to conduct an N-alkylation reaction, wherein the temperature of the first swelling reaction is 20° C. to 40° C., and the time is 1 h to 6 h.

[0087] In the present application, the chlorine ball is first swelled in the first solvent, so that the molecular structure of the chlorine ball becomes loose, and the phthalimide salt can easily enter the interior of the chlorine ball to react, thereby accelerating the reaction rate and improving the reaction uniformity, which is beneficial to increasing the nitrogen content of the amino resin.

[0088] Optionally, the reagent causing the precursor to undergo a decomposition reaction includes one or more of hydrazine and an inorganic base. The inorganic base includes one or more of NaOH, KOH and LiOH; the inorganic base can be provided in the form of an alcohol solution, such as an ethanol solution of NaOH, and the mass fraction of the inorganic base in the alcohol solution is 5% to 15%, such as 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14% or 15%.

[0089] Optionally, the reagent that causes the precursor to undergo a decomposition reaction is an alcohol solution of an inorganic base, and the mass ratio of the chlorine ball, the phthalimide salt, and the alcohol solution of the inorganic base is 1:(0.4-0.8):(1-5). As an example, the mass ratio of the chlorine ball to the phthalimide salt is 1:0.4, 1:0.5, 1:0.6, 1:0.7, or 1:0.8, and the mass ratio of the chlorine ball to the alcohol solution of the inorganic base can be 1:1, 1:2, 1:3, 1:4, or 1:5.

[0090] Optionally, the reagent that causes the precursor to undergo a decomposition reaction is hydrazine, and the mass ratio of the chlorine ball, the phthalimide salt and the hydrazine is 1:(0.4-0.8):(0.8-1.5), and can further be 1:(0.4-0.6):(0.8-1.0). As an example, the mass ratio of the chlorine ball and the phthalimide salt is 1:0.4, 1:0.5, 1:0.6, 1:0.7 or 1:0.8, and the mass ratio of the chlorine ball and the hydrazine can be 1:0.8, 1:0.9, 1:1.0, 1:1.1, 1:1.2, 1:1.3, 1:1.4 or 1:1.5.

[0091] Optionally, after the N-alkylation reaction and / or after the decomposition reaction, a purification step is further included. The purification step includes one or more of filtration, cleaning and drying. The filtration method includes ordinary filtration or reduced pressure filtration; the cleaning method includes ordinary cleaning or ultrasonic cleaning, and the cleaning liquid may be water, methanol, ethanol or acetone; the drying method includes forced air drying or vacuum drying, and the drying temperature may be 30°C to 50°C, and the drying time may be 3h to 6h.

[0092] In the present application, R is absent or selected from substituted or unsubstituted C1~C9 alkylene. As an example, when R is present, it can be selected from C1 alkylene, C2 alkylene, C3 alkylene, C4 alkylene, C5 alkylene, C6 alkylene, C7 alkylene, C8 alkylene or C9 alkylene, and the substituent on the C1~C9 alkylene can be an alkyl, alkoxy, cycloalkyl, heterocyclic, aryl, heteroaryl, aldehyde, carboxyl, ester, cyano, isocyano, amino, nitro, hydroxyl or halogen, and the above groups can also be further substituted by substituents acceptable in the art.

[0093] Optionally, R is absent or selected from one or more of hydroxy-substituted C1~C3 alkylene and alkoxy-substituted C1~C3 alkylene. As an example, when R is present, it can be selected from hydroxy-substituted C1 alkylene, hydroxy-substituted C2 alkylene, hydroxy-substituted C3 alkylene, alkoxy-substituted C1 alkylene, alkoxy-substituted C2 alkylene, alkoxy-substituted C3 alkylene, and C1~C3 alkylene substituted by at least one hydroxyl group and at least one alkoxy group.

[0094] Optionally, the aldose includes one or more of glyceraldehyde, glucose, galactose, mannose, maltose, ribose, deoxyribose, threose, erythrose, lyxose, xylose, arabinose, talose, idose, gulose, altrose and allose. Further optionally, the aldose includes one or more of glyceraldehyde, glucose, galactose, mannose, maltose, ribose and deoxyribose.

[0095] If R does not exist, the aldose is glyceraldehyde containing one chiral carbon atom, and glyceraldehyde has two enantiomers, L-type and D-type, and their Fischer projection formulas are shown in general formulas (II-1a) and (II-1b), respectively. If R is selected from C3 alkylene substituted with three hydroxyl groups (-CH(OH)-CH(OH)-CH(OH)-), the aldose can be glucose, galactose or mannose, and these three monosaccharides are diastereomers of each other, and their Fischer projection formulas are shown in general formulas (II-2), (II-3) and (II-4), respectively. Maltose is a disaccharide formed by two glucose molecules connected by an α-1,4-glycosidic bond, and it can be regarded as R selected from C3 alkylene substituted with two hydroxyl groups and one alkoxy group, and its Fischer projection formula is shown in general formula (II-5). If R is selected from C2 alkylene substituted with two hydroxyl groups (-CH(OH)-CH(OH)-), the aldose is ribose, and its Fischer projection formula is shown in general formula (II-6). If R is selected from a hydroxy-substituted C2 alkylene group (-CH2-CH(OH)-), the aldose is deoxyribose, and its Fischer projection formula is shown in general formula (II-7). In addition, if R is selected from a hydroxy-substituted C1~C3 alkylene group, the aldose can also be threose, erythrose, lyxose, xylose, arabinose, talose, idose, gulose, altrose or allose, and its Fischer projection formula is not repeated here.

[0096] (II-1a); (II-1b);

[0097] (Ⅱ-2); (II-3); (II-4);

[0098] (II-5);

[0099] (II-6); (Ⅱ-7).

[0100] In the present application, the amino group in the amino resin and the aldehyde group in the aldose undergo nucleophilic addition reaction at a molar ratio of 1:1. The nitrogen content of the amino resin is different, and the structure of the selected aldose is different, so that the mass ratio of the amino resin and the aldose is greatly different. Optionally, the mass ratio of the amino resin and the aldose is 1:(0.4~1.0), and further can be 1:(0.4~0.6). As an example, the mass ratio of the amino resin and the aldose can be 1:0.4, 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9 or 1:1.

[0101] In the process of synthesizing polyhydroxy chelate resin, the applicant found that the yield and purity of polyhydroxy chelate resin were not good when the reductive amination reaction was carried out at room temperature or under heating conditions. After further investigation, it was found that the reductive amination reaction was an exothermic reaction, so lowering the reaction temperature was conducive to promoting the reductive amination reaction to proceed in the forward direction, thereby improving the yield and purity of polyhydroxy chelate resin.

[0102] Optionally, the reaction temperature of the nucleophilic addition reaction is 0° C. to 10° C., further optionally 0° C. to 5° C., and further optionally 0° C. As an example, the reaction temperature of the nucleophilic addition reaction can be 0° C., 1° C., 2° C., 3° ​​C., 4° C., 5° C., 6° C., 7° C., 8° C., 9° C. or 10° C.

[0103] Optionally, the reaction time of the nucleophilic addition reaction is 2 h to 6 h, further optionally 2 h to 4 h, and further optionally 3 h. As an example, the reaction time of the nucleophilic addition reaction can be 2 h, 2.5 h, 3 h, 3.5 h, 4 h, 4.5 h, 5 h, 5.5 h or 6 h.

[0104] Optionally, the nucleophilic addition reaction is carried out in a second solvent. It is understandable that the second solvent does not react with the amino resin or aldose, and the amount of the second solvent is determined by factors such as reaction time, reaction temperature, type of solvent, type of raw material, and reaction scale. Among them, the second solvent includes one or more of N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), methanol (MeOH), and ethanol (EtOH), and further N,N-dimethylformamide (DMF) can be selected; the mass ratio of the second solvent to the amino resin is 1: (0.1~0.5), and further 1: (0.15~0.25) can be selected.

[0105] Optionally, the amino resin and the aldose are subjected to a nucleophilic addition reaction, comprising the following steps: mixing the amino resin and the second solvent, conducting a second swelling reaction, and adding the aldose to conduct a nucleophilic addition reaction, wherein the second swelling reaction is conducted at a temperature of 20° C. to 40° C. for a time of 1 h to 6 h.

[0106] In the present application, the amino resin is first swelled in the second solvent, so that the molecular structure of the amino resin becomes loose, and the aldose easily enters the interior of the amino resin for nucleophilic addition reaction, thereby accelerating the reaction rate and improving the reaction uniformity, which is beneficial to increasing the hydroxyl content of the polyhydroxy chelate resin. If the swelling treatment is not performed, the subsequent reaction time will be increased, affecting the production efficiency.

[0107] S200: subjecting the Schiff base intermediate and the reducing agent to a reduction reaction to prepare a polyhydroxy chelating resin.

[0108] Optionally, the reducing agent includes one or more of sodium borohydride (NaBH4), sodium cyanoborohydride (NaBH3CN) and sodium triacetoxyborohydride (STAB, NaBH(CH3COO)3). Further optionally, the reducing agent is sodium triacetoxyborohydride (STAB).

[0109] Among them, sodium triacetoxyborohydride, also known as sodium acetate borohydride, can be used for the reduction reaction of ketones and aldehydes, the reduction amination or lactamization of carbonyl compounds and amines, and the reduction amination of aromatic aldehydes. STAB has become the preferred catalyst for reduction amination reactions due to its wide applicability, high selectivity, mild reaction conditions, good catalytic reduction performance, easy separation and purification, and no pollution to the environment.

[0110] Optionally, the mass ratio of the amino resin to the reducing agent is (1-10): 1, further optionally (1-5): 1, and further optionally 4: 1. As an example, the mass ratio of the amino resin to the reducing agent may be 1: 1, 2: 1, 3: 1, 4: 1, 5: 1, 6: 1, 7: 1, 8: 1, 9: 1 or 10: 1.

[0111] In the present application, step S100 and step S200 are carried out in the same reaction system. After the synthesis of the Schiff base intermediate, there is no need to purify the reaction system, and a reducing agent is directly added to reduce the Schiff base intermediate. In other words, the reduction reaction is also carried out in the second solvent, and the second solvent does not react with the reducing agent. Similarly, reducing the reaction temperature of the reduction reaction is conducive to improving the productivity and purity of the polyhydroxy chelating resin.

[0112] Optionally, the reaction temperature of the reduction reaction is 0°C to 10°C, further optionally 0°C to 5°C, and further optionally 0°C. As an example, the reaction temperature of the reduction reaction may be 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C or 10°C.

[0113] Optionally, the reaction time of the reduction reaction is 8 h to 12 h, further optionally 9 h to 11 h, and further optionally 10 h. As an example, the reaction time of the reduction reaction can be 8 h, 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, 11.5 h or 12 h.

[0114] Optionally, after the reduction reaction, the method further comprises the following steps: a step of purifying the mixture containing the polyhydroxy chelate resin. The purification treatment comprises one or more of filtration treatment, cleaning treatment and drying treatment. The filtration treatment method comprises ordinary filtration or reduced pressure filtration; the cleaning treatment method comprises ordinary cleaning or ultrasonic cleaning, and the cleaning liquid may be water, methanol, ethanol or acetone; the drying treatment method comprises forced air drying or vacuum drying, and the drying temperature may be 30°C to 50°C, and the drying time may be 3h to 6h.

[0115] In a second aspect of the present application, a polyhydroxy chelate resin is provided, which is prepared by the method for preparing the polyhydroxy chelate resin as described above.

[0116] Optionally, the hydroxyl content of the polyhydroxy chelating resin is 45% to 95%.

[0117] Among them, the hydroxyl content of the polyhydroxy chelating resin is tested by KOH titration method, and the testing principle is as follows: acetic anhydride is used as an esterification reagent to react with the hydroxyl groups in the polyhydroxy chelating resin; after the esterification reaction is completed, an acid-base indicator is added, and the acetic acid in the esterification product is titrated with KOH aqueous solution as a standard solution to determine the hydroxyl content. The acid-base indicator can be one or more of phenolphthalein, cresol red and thymol blue. The amount of hydroxyl content can be described by the hydroxyl value (Hydroxyl value), that is, how many milligrams of KOH are contained in each gram of sample; the hydroxyl value can also be converted into a percentage, the conversion coefficient is 33, and the conversion formula is: hydroxyl content (unit is %) × 33 = hydroxyl value (unit is mg KOH / g).

[0118] Specifically, the KOH titration method includes the following steps:

[0119] (1) Weigh 2g~5g of resin sample and digest it using a microwave digester. Filter the digestion product and transfer it to a beaker. Heat it on a flat heater and concentrate it to 2g~5g.

[0120] (2) Perform the following operations on the sample group and the blank control group respectively:

[0121] Sample group: Weigh 2g~5g of digestion solution and place it in a 250mL conical flask. Accurately pipette and add 5mL of 2M acetic anhydride in ethyl acetate solution. Heat the conical flask in a 50℃ water bath. After heating for 5min, remove the heat source and shake the conical flask carefully to dissolve the esters. Add 10mL of 75% pyridine aqueous solution and leave it for at least 10min.

[0122] Blank control group: No 2g~5g digestion solution was added, and the rest of the operations were the same as those of the sample group;

[0123] (3) Add 10 drops of acid-base indicator (phenolphthalein) to a conical flask and titrate with a KOH solution of molar concentration N until the color of the solution changes from colorless to purple-red, which is the titration endpoint. Record the volume of KOH solution consumed and calculate the hydroxyl content of the polyhydroxy chelating resin according to the following formula:

[0124] Hydroxyl content = [(V0-V1) × N × 56.1 ÷ m] ÷ 33

[0125] Wherein, V0 is the volume of KOH solution consumed by the blank control group, V1 is the volume of KOH solution consumed by the sample group, N is the molar concentration of the KOH solution, m is the mass of the resin sample, 33 is the conversion coefficient, and 56.1 is the relative molecular mass of KOH.

[0126] It is understandable that the adsorption capacity of polyhydroxy chelating resin for boron will be affected by the boron content in the solution system, and the existence form of boron will also be affected by the boron content in the solution system. Boron in the solution system can usually be expressed as "B4O7 2- " is expressed in the form of comprehensive statistics. The test conditions for the adsorption capacity of polyhydroxy chelating resin are as follows: the boron-containing wastewater is adsorbed by polyhydroxy chelating resin, and then the B4O7 of the boron-containing wastewater before and after adsorption is tested by ICP-MS. 2- The change of content can be used to calculate the polyhydroxy chelating resin at a certain B4O7 2- In some specific examples, the B4O7 content of boron-containing wastewater is 2- Content is 371.61ppm, and adsorption time is 10h, and the boron adsorption capacity of polyhydroxy chelating resin is measured to be ≥28mg / g, and further can be selected as 28mg / g~50mg / g. As an example, the boron adsorption capacity of polyhydroxy chelating resin can be 28mg / g, 28.049mg / g, 30mg / g, 32mg / g, 34mg / g, 36mg / g, 38mg / g, 40mg / g, 42mg / g, 44mg / g, 46mg / g, 48mg / g or 50mg / g.

[0127] Optionally, the porosity of the polyhydroxy chelate resin is 30% to 70%. As an example, the porosity of the polyhydroxy chelate resin can be 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% or 70%.

[0128] Optionally, the particle diameter of the polyhydroxy chelate resin is 0.3 mm to 1.1 mm. As an example, the particle diameter of the polyhydroxy chelate resin can be 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm or 1.1 mm.

[0129] In a third aspect of the present application, a boron removal method is provided, comprising the following steps: using the polyhydroxy chelating resin as described above to perform adsorption treatment on boron-containing wastewater.

[0130] As an example, boron-containing wastewater can be battery recovery liquid, salt lake brine or other boron-containing wastewater generated in other industrial production processes. Battery recovery liquid includes not only lithium battery recovery liquid, but also recovery liquid of lead-acid batteries, nickel-hydrogen batteries and other batteries; salt lake brine can be chloride-type salt lake brine, sulfate-type salt lake brine or carbonate-type salt lake brine.

[0131] Optionally, the boron-containing wastewater is subjected to adsorption treatment using a polyhydroxy chelating resin, comprising the following steps: the polyhydroxy chelating resin is loaded into a chromatography column, and the boron-containing wastewater is passed through the chromatography column for adsorption treatment.

[0132] It is understandable that the chromatography column may also be referred to as an adsorption column or a resin column. In some specific examples, the chromatography column is a glass jacketed chromatography column with a packing height of ≥600 mm and a column diameter of ∼1.9 cm.

[0133] Optionally, the pH of the boron-containing solution is 4 to 8. As an example, the pH of the boron-containing solution can be 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5 or 8.

[0134] Traditional N-methylglucosamine modified resins are greatly affected by pH, and have a good boron removal effect in weakly alkaline boron-containing wastewater, but a poor boron removal effect in acidic boron-containing wastewater. In contrast, the polyhydroxy chelating resin prepared in this application has a wide pH application range, has excellent adsorption capacity and adsorption rate under different pH conditions, and is suitable for boron removal treatment in complex multivariate environments such as battery recovery liquid, salt lake brine and other boron-containing wastewater.

[0135] Optionally, the mass volume ratio of the polyhydroxy chelating resin to the boron-containing wastewater is 5 g / L to 500 g / L, for example 5 g / L, 10 g / L, 20 g / L, 50 g / L, 80 g / L, 100 g / L, 150 g / L, 200 g / L, 250 g / L, 300 g / L, 350 g / L, 400 g / L, 450 g / L or 500 g / L.

[0136] Optionally, the temperature of the adsorption treatment is 25°C to 50°C, for example, 25°C, 30°C, 35°C, 40°C, 45°C or 50°C.

[0137] Optionally, the flow rate of the adsorption treatment is 1 BV / h to 10 BV / h, for example, 1 BV / h, 2 BV / h, 3 BV / h, 4 BV / h, 5 BV / h, 6 BV / h, 7 BV / h, 8 BV / h, 9 BV / h or 10 BV / h.

[0138] It is understandable that the time of adsorption treatment takes into account factors such as the content of each component of the boron-containing solution, the processing volume of the boron-containing solution, the amount of polyhydroxy chelating resin, the adsorption temperature and flow rate. Optionally, the time of adsorption treatment is 1h~10h, including but not limited to: 1h, 2h, 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h.

[0139] Optionally, after the boron-containing wastewater is subjected to adsorption treatment, the method further comprises the following steps: regenerating the boron-loaded resin obtained after the adsorption treatment to prepare a regenerated polyhydroxy chelating resin.

[0140] Optionally, the regeneration process comprises a pickling process. The acid solution used in the pickling treatment contains one or more of hydrochloric acid, sulfuric acid, nitric acid, oxalic acid and citric acid; the mass fraction of the acid in the acid solution is 1% to 20%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20%; the flow rate of the pickling treatment is 0.5BV / h to 5BV / h, for example, 0.5BV / h, 1BV / h, 1.5BV / h, 2BV / h, 2.5BV / h, 3BV / h, 3.5BV / h, 4BV / h, 4.5BV / h or 5BV / h; the time of the pickling treatment takes into account factors such as the mass and boron content of the boron-loaded resin, the composition and mass fraction of the acid solution, the pickling temperature and flow rate, and the time of the pickling treatment can be 0.5h to 5h, for example, 0.5h, 1h, 2h, 3h, 4h or 5h.

[0141] The following is further described in conjunction with specific examples and comparative examples. The raw materials involved in the following specific examples and comparative examples, unless otherwise specified, can all be commercially available, the instruments used, unless otherwise specified, can all be commercially available, and the processes involved, unless otherwise specified, are all conventionally selected by those skilled in the art. Among them, the chlorine balls were purchased from Wandong High-Tech (Tianchang) Co., Ltd., with a brand name of LQ117.

[0142] Example 1

[0143] See also Figure 1 and Figure 2 ,in, Figure 1 Is the synthetic route diagram of the amino resin of the present embodiment, Figure 2 The synthetic route of the polyhydroxy chelating resin of this embodiment is shown in FIG. 1 , wherein compound 11 is a chlorine ball, compound 12 is a precursor, compound 13 is an amino resin, compound 14 is glucose, compound 15 is a Schiff base intermediate, and compound 16 is a polyhydroxy chelating resin.

[0144] The preparation method of the polyhydroxy chelating resin of the present embodiment is as follows:

[0145] (1) Preparation of amino resin: Weigh a certain amount of chlorine balls, place them in N,N-dimethylformamide (DMF), carry out the first swelling reaction at room temperature for 2 hours; add potassium phthalimide, stir for 0.5 hours, heat to 80°C at a heating rate of 2°C / min, carry out N-alkylation reaction for 6 hours, and obtain a mixed solution containing a precursor; add hydrazine to carry out hydrazinolysis reaction for 8 hours to obtain a mixed solution containing amino resin; filter the mixed solution containing amino resin, wash the obtained filter residue with ethanol several times, and dry it at 50°C for 6 hours to obtain amino resin. The mass ratio of chlorine balls, DMF, potassium phthalimide and hydrazine is 1:5:0.4:0.8.

[0146] (2) Preparation of Schiff base intermediate: Weigh a certain amount of amino resin, place it in DMF, and carry out a second swelling reaction at room temperature for 2 hours; add glucose, stir at 0°C for 3 hours, and carry out a nucleophilic addition reaction to obtain a mixed solution containing Schiff base intermediate. The mass ratio of amino resin to DMF is 1:5.

[0147] (3) Preparation of polyhydroxy chelating resin: sodium triacetoxyborohydride (STAB) is added to the mixed solution containing the Schiff base intermediate, and the mixture is stirred for 10 hours at 0°C to perform a reduction reaction to obtain a mixed solution containing polyhydroxy chelating resin; the mixed solution containing polyhydroxy chelating resin is filtered, and the filter residue obtained is washed several times with pure water to obtain polyhydroxy chelating resin. The mass ratio of amino resin, glucose and STAB is 1:0.4:0.25.

[0148] Example 2

[0149] The difference between this embodiment and embodiment 1 is that glucose is replaced by maltose of the same molar concentration.

[0150] Example 3

[0151] The difference between this embodiment and embodiment 1 is that glucose is replaced by ribose of the same molar concentration.

[0152] Comparative Example 1

[0153] The polyhydroxy chelate resin of this comparative example is a commercially available N-methylglucosamine modified resin (Dusheng, CH-99).

[0154] Comparative Example 2

[0155] In this comparative example, chitosan powder is granulated to obtain a polyhydroxy chelate resin. The method for granulating chitosan powder is as follows: chitosan powder is mixed with dimethyl sulfoxide at a mass ratio of 1:5 to obtain a uniform mixed solution. Polyacrylonitrile is added to the mixed solution at a mass mixing ratio of chitosan powder and polyacrylonitrile of 1:2. After being stirred evenly, it is added dropwise to water using a syringe to form a spherical adsorption material with a particle size of 0.71 mm to 1.3 mm.

[0156] Test Case

[0157] (1) Figure 3 The figure is a physical picture of the polyhydroxy chelating resin of Example 1. Figure 3 It can be seen that the particle diameter of the polyhydroxy chelate resin of Example 1 is 0.35mm-1.1mm, and the particle diameter is uniform. The particle diameters of the remaining embodiments and comparative examples are shown in Table 1.

[0158] (2) Figure 4 It is the infrared spectrogram of the polyhydroxy chelating resin of embodiment 1. Figure 4 Medium, 3000~3050cm -1 The characteristic peaks at 3350-3250 cm -1 The characteristic peak at confirms that the product surface contains hydroxyl functional groups, which indicates that the polyhydroxy chelating resin in Example 1 has a structure as shown in the general formula (IV).

[0159] (3) Nitrogen content of amino resin: The nitrogen content of amino resin in Example 1 was 20 atm.% as determined by XPS. The nitrogen contents of amino resins in other examples and comparative examples are shown in Table 1. The nitrogen content of Examples 1 to 3 was tested on amino resins; the nitrogen content of Comparative Example 1 was tested on CH-99 resin, which is an N-methylglucosamine modified resin, and the nitrogen on each grafting site comes from N-methylglucosamine in the raw material; the nitrogen content of Comparative Example 2 was tested on a spherical adsorption material obtained by granulation of chitosan, and the nitrogen in the adsorption material comes from polyacrylonitrile used in the granulation process.

[0160] (4) Hydroxyl content of polyhydroxy chelate resin: The hydroxyl content of the polyhydroxy chelate resin in Example 1 was 80% as measured by KOH titration. The hydroxyl content of the polyhydroxy chelate resins in the remaining Examples and Comparative Examples are shown in Table 1.

[0161] (5) Adsorption performance under acidic conditions: 10 mL of polyhydroxy chelating resin was loaded into a glass chromatography column, and the boron-containing wastewater was adsorbed. The boron-containing wastewater was taken from a battery manufacturer in Fujian. The total volume of the boron-containing wastewater was 20 BV, the pH was 4.68, the flow rate was 2 BV / h, and the adsorption time was 10 h. The boron content of the boron-containing wastewater before and after the adsorption treatment was determined by ICP-MS, and the boron adsorption capacity was calculated. The results are shown in Tables 1 and 2.

[0162] As shown in Table 1, in Examples 1 to 3, there is a proportional relationship between the nitrogen content of the amino resin, the hydroxyl content of the polyhydroxy chelate resin and the boron adsorption capacity, which shows that the hydroxyl content of the polyhydroxy chelate resin increases, making the polyhydroxy chelate resin contain more adsorption sites and coordination functional groups, thereby showing excellent adsorption capacity and adsorption rate.

[0163] As shown in Table 2, the boron content in the boron-containing wastewater is 371.61ppm, and the contents of the three metal elements of lithium, calcium and sodium are 2070.1ppm, 16.46ppm and 59046ppm respectively. The polyhydroxy chelate resin of Examples 1 to 3 is used for adsorption treatment, and the boron content in the boron-containing wastewater can be reduced to below 120ppm, the boron adsorption rate can reach more than 67.81%, and the adsorption rate of lithium, calcium and sodium can be maintained at below 2.67%, indicating that the polyhydroxy chelate resin of Examples 1 to 3 not only has a higher boron adsorption capacity and a higher boron adsorption rate, but also shows excellent selectivity in a multi-component complex solution system.

[0164] Compared with Examples 1 to 3, the polyhydroxy chelate resin of Comparative Example 1 is a traditional N-methylglucosamine modified resin, which not only reduces the boron adsorption rate, but also significantly improves the adsorption rates of lithium, calcium and sodium, especially the adsorption rate of sodium ions reaches 53.40%, and the selectivity is very poor, which is not suitable for the boron removal treatment of multi-component complex solution systems. The polyhydroxy chelate resin of Comparative Example 2 uses chitosan as a raw material, and also has the defects of low boron adsorption rate and poor selectivity.

[0165] (6) Adsorption performance under alkaline conditions: Similarly, 10 mL of the polyhydroxy chelating resin of Example 1 was loaded into a glass chromatography column, and the boron-containing wastewater with a pH of 7.80 was subjected to adsorption treatment. The process parameters of the adsorption treatment were consistent with those in step (5). The results are shown in Table 2.

[0166] It can be seen from Table 2 that the polyhydroxy chelating resin of Example 1 can show good boron removal effect under both acidic conditions (pH=4.68) and alkaline conditions (pH=7.80), and the boron adsorption rate and selectivity under acidic conditions are slightly better than those under alkaline conditions.

[0167] (7) Regeneration performance: After the adsorption treatment, the boron-loaded resin was regenerated using a 5 wt.% HCl solution, the total volume of the HCl solution was 3 BV, the flow rate was 2 BV / h, and the time was 1.5 h; then the adsorption treatment was performed again according to step (5) or step (6), and a total of 3 adsorption-regeneration cycles were performed. After each adsorption-regeneration cycle, the resin regeneration rate was calculated according to the following formula: Resin regeneration rate = (desorption amount ÷ adsorption amount) × 100%, and the average value of the three cycles was taken as the final numerical regeneration rate. The results are shown in Table 3.

[0168] It can be seen from Table 3 that the resin regeneration rates of Examples 1 to 3 are significantly better than those of Comparative Examples 1 to 2, and the polyhydroxy chelating resin prepared with ribose as raw material has the highest resin regeneration rate and high industrial application value.

[0169] Table 1. Related parameters of polyhydroxy chelating resin

[0170]

[0171] Table 2. Adsorption performance of polyhydroxy chelating resin

[0172]

[0173] Table 3. Regeneration performance of polyhydroxy chelating resin

[0174]

[0175] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0176] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of protection of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the scope of protection of the present application. Therefore, the scope of protection of the present application shall be subject to the attached claims.

Claims

1. A method for preparing a polyhydroxy chelating resin, characterized in that: The following steps are involved: A Schiff base intermediate having a structure as shown in the general formula (III) is prepared by subjecting an amino resin having a structure as shown in the general formula (I) and an aldose having a structure as shown in the general formula (II) to a nucleophilic addition reaction; The Schiff base intermediate and the reducing agent are subjected to a reduction reaction to prepare a polyhydroxy chelating resin having a structure as shown in the general formula (IV); Wherein, n is a positive integer; R is absent or is selected from substituted or unsubstituted C1-C9 alkylene; The nitrogen content of the amino resin is 15 atm.% to 25 atm.%.

2. The method for preparing a polyhydroxy chelating resin according to claim 1, wherein R is absent or is selected from one or more of hydroxy-substituted C1-C3 alkylene and alkoxy-substituted C1-C3 alkylene.

3. The preparation method of polyhydroxy chelate resin as claimed in claim 2, characterized in that, The aldose includes one or more of glyceraldehyde, glucose, galactose, mannose, maltose, ribose, deoxyribose, threose, erythrose, lyxose, xylose, arabinose, talose, idose, gulose, altrose and allose.

4. The method for preparing a polyhydroxy chelating resin according to claim 1, wherein The reducing agent includes one or more of sodium borohydride, sodium cyanoborohydride and sodium triacetoxyborohydride.

5. The method for preparing a polyhydroxy chelate resin according to any one of claims 1 to 4, characterized in that: The reaction temperatures of the nucleophilic addition reaction and the reduction reaction are both 0°C to 10°C.

6. The method for preparing a polyhydroxy chelate resin according to claim 5, wherein: One or more of the following conditions are met: (1) The mass ratio of the amino resin to the aldose is 1:(0.4-1.0); (2) The reaction time of the nucleophilic addition reaction is 2 h to 6 h; (3) The mass ratio of the amino resin to the reducing agent is 1:(1-10); (4) The reaction time of the reduction reaction is 8h to 12h.

7. The method for preparing a polyhydroxy chelate resin according to any one of claims 1 to 4, characterized in that: The preparation method of the amino resin comprises the Gabriel synthesis method.

8. The method for preparing a polyhydroxy chelate resin according to claim 7, wherein The preparation method of the amino resin comprises the following steps: The precursor is prepared by subjecting chlorine balls and phthalimide salt to N-alkylation reaction; The precursor is subjected to a decomposition reaction to prepare the amino resin.

9. The method for preparing a polyhydroxy chelating resin according to claim 8, wherein The reagent causing the precursor to undergo a decomposition reaction comprises one or more of hydrazine and an inorganic base.

10. A polyhydroxy chelating resin, characterized in that, The polyhydroxy chelate resin is prepared by the preparation method of the polyhydroxy chelate resin according to any one of claims 1 to 9.

11. The polyhydroxy chelate resin according to claim 10, wherein One or more of the following conditions are met: (1) The particle size of the polyhydroxy chelating resin is 0.3 mm to 1.1 mm; (2) The hydroxyl content of the polyhydroxy chelate resin is 45% to 95%; (3) B4O7 in boron-containing wastewater 2- Under the conditions of a boron content of 371.61 ppm and an adsorption time of 10 h, the boron adsorption capacity of the polyhydroxy chelating resin is ≥ 28 mg / g; (4) The porosity of the polyhydroxy chelate resin is 30% to 70%.

12. A method for removing boron, characterized in that: The following steps are involved: The boron-containing wastewater is subjected to adsorption treatment using the polyhydroxy chelating resin as described in claim 10 or 11.

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