A crown ether functionalized silica gel material and its preparation method and application

Abstract

The invention discloses a crown ether functionalized silica gel material and its preparation method and application; the crown ether functionalized silica gel material is prepared by reacting a multifunctional amino functionalized silica gel material with a benzo crown ether derivative with an aldehyde group; or the multifunctional amino functionalized silica gel material is reacted with a benzo crown ether derivative with an aldehyde group, and then reacted with a crown ether compound with an alkenyl group, a carboxyl group or a halogen group; the invention fixes the crown ether on the silica gel material in the form of a skeleton through the reaction of the benzo crown ether derivative with the amino group at the end of the polyamine silane chain in the multifunctional amino functionalized silica gel material, forming a three-dimensional molecular cage structure; and further links the crown ether on the side of the molecular cage, increases the crown ether loading amount, and enhances the binding effect between the material and the target substance. The crown ether functionalized silica gel material of the invention is used as an adsorbent for cesium adsorption, can achieve high adsorption capacity and selectivity, and has excellent cyclic regeneration ability.

Description

Technical Field

[0001] The invention belongs to the technical field of adsorption materials, and in particular relates to a crown ether functionalized silica gel material and a preparation method and application thereof. Background Art

[0002] Cesium exists in salt lakes in the form of ions and reacts with Cs + High concentration Li with similar physical and chemical properties + 、Na + , K + The alkali metal ions coexist, so the trace amount of Cs can be selectively extracted from the high concentration coexisting ions with similar properties. + This is the main technical difficulty in extracting cesium from salt lake brine. Among the commonly used separation methods, adsorption is one of the most effective technologies because it is simple to operate, highly practical, and easy to regenerate, compared to membrane separation, ion exchange, chemical precipitation, and electrochemical methods.

[0003] As traditional adsorption materials, silicon-based materials not only stand out among carbon materials, resins, biomass, crystalline materials, etc. due to their inorganic-organic hybridization ability, stable three-dimensional structure and easy functionalization design advantages, but their low cost and simple synthesis conditions also enable silicon-based materials to achieve industrial large-scale production.

[0004] With specific adsorption of Cs + There are many types of substances. Metal ferrocyanide, as the most common material, has the disadvantage of low selectivity. Although ammonium phosphomolybdate has excellent performance, it is difficult to firmly combine with the material matrix through chemical reaction as an inorganic material, so there is a phenomenon of poor cyclic stability caused by the loss of AMP during use. The unique polyoxy crown structure of crown ether compounds makes them significantly negatively charged and can form stable complexes with cations. The size of 18-crown 6 ether is similar to that of Cs + The diameters match and can quickly and accurately anchor Cs in salt lakes + Achieve highly selective adsorption. However, the existing composite adsorbents for selective adsorption of cesium ions are mostly low in grafting rate, resulting in the actual effect not meeting expectations. Improving the crown ether grafting sites and organically combining them with silica gel is one of the effective ideas to break through the current bottleneck. Summary of the invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a crown ether functionalized silica gel material and its preparation method and application; the present invention fixes the crown ether on the silica gel material in the form of a skeleton by reacting the benzocrown ether derivative with the polyamine silane chain end amino group in the multifunctional amino functionalized silica gel material to form a three-dimensional molecular cage structure; and further branches the crown ether on the side of the molecular cage to increase the crown ether loading and enhance the binding effect between the material and the target substance. The crown ether functionalized silica gel material of the present invention is used as an adsorbent for cesium adsorption, which can achieve high adsorption capacity and selectivity, and has excellent cyclic regeneration ability.

[0006] In order to achieve the above technical objectives and the above technical effects, the present invention is implemented through the following technical solutions:

[0007] The present invention provides a crown ether functionalized silica gel material, which is prepared by reacting a compound represented by structural formula I with a benzocrown ether derivative having an aldehyde group represented by structural formula II; wherein the terminal amino group in the compound represented by structural formula I reacts with the aldehyde group of the benzocrown ether derivative;

[0008] Wherein, structural formula I is:

[0009] [(O 3 / 2 )Si(CH2) m NH[C2H4NH] p-1 C2H4NH2] a [(O 4 / 2 )Si] b [VSi(O 3 / 2 )] c [WSi(O 3 / 2 )] d ; V is a substituent group selected from C 1-22 Alkyl, C 2-22 Alkenyl or C 1-22 Alkylaryl; W is a substituent group selected from C 1-20 Mercaptoalkyl, C 2-20 Alkyl sulfide group, C 1-22 Alkyl sulfide alkyl or C 2-20 Alkylene sulfide alkyl, C 2-20 Alkyl thioether aryl, C 2-20 Alkylene sulfide aryl or C 2-6 Alkyl SC 2-6 AlkylNHC(=S)NHR 1 ; Through the silicon atoms, hydrogen, straight or branched C 1-22 Alkyl, terminal group (R 2 )3SiO 1 / 2 , cross-linking agent or chain R 2 q Si(OR 3 )g O k / 2 or one or more of the silicon atoms of other groups in formula I saturate the free valence of the silicate oxygen atoms; R 1 , R 2 , R 3 Selected from linear or branched C 1-12 Alkyl, aryl or C 1-22 Alkyl aryl; k is an integer from 1 to 3, q ​​is an integer from 1 to 2, g is an integer from 0 to 2, and satisfies g+k+q=4; m is an integer from 2 to 12; p is an integer from 2 to 100; a, b, c, d are all integers, and the ratio of [a+c]:b is between 0.00001 and 100000; a and b are always present, and when c and d are greater than zero, the ratio of c+d to a+b is between 0.000001 and 100000; when end groups, crosslinking agents and / or polymer chains are present, their molar ratio to a+b+c+d is between 0 and 999:1;

[0010] Wherein, the structural formula II of the benzocrown ether derivative with an aldehyde group is one of the following structural formulas:

[0011] ;

[0012] wherein R1, R2, R3, R4, R1', R2', R3', R4' are selected from hydrogen, straight chain or branched C 1-12 Alkyl, C 2- C 22 Alkenyl or alkynyl, aryl or C 1-22 Alkyl aryl; T1, T2, T3, T4, T1', T2', T3', T4' may be independently present or absent, and when present, T1, T2, T3, T4, T1', T2', T3', T4' are selected from linear or branched C 1-12 Alkyl, C 2- C 22 Alkenyl or alkynyl, aryl or C 1-22 Alkyl aryl; n1, n2 are integers from 1 to 6 respectively, preferably n1=n2.

[0013] The preparation method of the crown ether functionalized silica gel material comprises the following steps:

[0014] (11) 4 O)3Si(CH2) m X 1 and polyethylene polyamine NH2[C2H4NH] p-1 C2H4NH2 reacts to form silane (R 4 O)3Si(CH2) m NH[C2H4NH] p-1C2H4NH2,X 1 It is a halogen element; R 4 Selected from C 1-22 alkyl;

[0015] (12) Add WSi(OR) as needed to the silane coupling agent prepared in step (1) in a solvent through reflux reaction. 5 )3 and / or VSi(OR 6 )3, and grafted onto silica gel, or reacted with sodium silicate or tetraalkyl orthosilicate to form a silica gel precursor as shown in formula I; R 5 , R 6 Selected from C 1-22 alkyl;

[0016] (13) The silica precursor obtained in step (12) is mixed with the benzocrown ether derivative having an aldehyde group shown in structural formula II in a solvent, and refluxed for a certain time under certain conditions. The product is filtered and washed multiple times, and then dried to obtain a crown ether functionalized silica gel material.

[0017] Furthermore, the reaction temperature of step (11) is 40-160°C, and the reaction time is 0.5-24h; (R 4 O)3Si(CH2) m X 1 and polyethylene polyamine NH2[C2H4NH] p-1 The molar ratio of C2H4NH2 is 1:1~6; X 1 Preferred are chlorine or bromine.

[0018] Furthermore, the silica gel grafting reaction temperature in step (12) is 40-160°C, and the reaction time is 0.5-24h. Typical solvents include toluene, xylene, heptane, ethanol and methanol. The silica gel grafting process is applicable to commercially available silica gel (including amorphous and spherical silica gel, preferably spherical silica gel); the silica gel particle size ranges from 100nm to 30mm; and the silica gel has a widely distributed known pore size, preferably a pore size between 40 and 250Å.

[0019] The sol-gel reaction in step (12) is carried out in the presence of an acidic or alkaline catalyst, at a reaction temperature of 20-160° C., and for a reaction time of 0.5 to 48 hours. Typical acids and bases used in the sol-gel reaction process are hydrochloric acid and ammonia water, respectively, but are not limited thereto, and the solvents used include, but are not limited to, methanol, ethanol, water, and mixtures thereof.

[0020] Furthermore, the reaction temperature in step (13) is 50-180°C, the reaction time is 2-12h; the mass ratio of the benzocrown ether derivative with an aldehyde group to the silica gel precursor is (0.01-10) mol:1g. The solvent is preferably at least one of ethanol, dimethyl sulfoxide, dichloromethane, acetonitrile, chloroform, and N,N-dimethylformamide; a catalyst is also added in step (13), and the selected catalyst is an aqueous solution of acetic acid with a concentration of 3-12M.

[0021] The present invention also provides another crown ether functionalized silica gel material, which is prepared by first reacting a compound shown in structural formula I with a benzocrown ether derivative with an aldehyde group shown in structural formula II, and then reacting with a crown ether compound with an alkenyl group, a carboxyl group or a halogen group; wherein the terminal amino group in the compound shown in structural formula I reacts with the aldehyde group of the benzocrown ether derivative, and the -NH- in the product after the reaction reacts with the crown ether compound with an alkenyl group, a carboxyl group or a halogen group;

[0022] Wherein, structural formula I is:

[0023] [(O 3 / 2 )Si(CH2) m NH[C2H4NH] p-1 C2H4NH2] a [(O 4 / 2 )Si] b [VSi(O 3 / 2 )] c [WSi(O 3 / 2 )] d ; V is a substituent group selected from C 1-22 Alkyl, C 2-22 Alkenyl or C 1-22 Alkylaryl; W is a substituent group selected from C 1-20 Mercaptoalkyl, C 2-20 Alkyl sulfide group, C 1-22 Alkyl sulfide alkyl or C 2-20 Alkylene sulfide alkyl, C 2-20 Alkyl thioether aryl, C 2-20 Alkylene sulfide aryl or C 2-6 Alkyl SC 2-6 AlkylNHC(=S)NHR 1 ; Through the silicon atoms, hydrogen, straight or branched C 1-22 Alkyl, terminal group (R 2 )3SiO 1 / 2 , cross-linking agent or chain R 2 q Si(OR 3 ) g O k / 2or one or more of the silicon atoms of other groups in formula I saturate the free valence of the silicate oxygen atoms; R 1 , R 2 , R 3 Selected from linear or branched C 1-12 Alkyl, aryl or C 1-22 Alkyl aryl; k is an integer from 1 to 3, q ​​is an integer from 1 to 2, g is an integer from 0 to 2, and satisfies g+k+q=4; m is an integer from 2 to 12; p is an integer from 2 to 100; a, b, c, d are all integers, and the ratio of [a+c]:b is between 0.00001 and 100000; a and b are always present, and when c and d are greater than zero, the ratio of c+d to a+b is between 0.000001 and 100000; when end groups, crosslinking agents and / or polymer chains are present, their molar ratio to a+b+c+d is between 0 and 999:1;

[0024] The structural formula II of the benzocrown ether derivative with an aldehyde group is one of the following structural formulas:

[0025]

[0026] wherein R1, R2, R3, R4, R1', R2', R3', R4' are selected from hydrogen, straight chain or branched C 1-12 Alkyl, C 2- C 22 Alkenyl or alkynyl, aryl or C 1-22 Alkyl aryl; T1, T2, T3, T4, T1', T2', T3', T4' may be independently present or absent, and when present, T1, T2, T3, T4, T1', T2', T3', T4' are selected from linear or branched C 1-12 Alkyl, C 2- C 22 Alkenyl or alkynyl, aryl or C 1-22 Alkylaryl; n1, n2 are integers from 1 to 6 respectively.

[0027] Furthermore, the structural formula III of the crown ether compound having an alkenyl group, a carboxyl group or a halogen group is one of the following structural formulas:

[0028] ;

[0029] X1, X2, X3, X4, X5, X6, X7, X8, X1', X2', X3', X4', X5', X6', X7', X8' are respectively selected from hydrogen, straight-chain or branched alkyl, alkenyl, alkynyl, aryl or alkylaryl, carboxyl or halogen, and in the corresponding structural formula at least one functional group is alkenyl, carboxyl or halogen, and n is 1 or 2.

[0030] Furthermore, in structural formula I, p is preferably an integer from 2 to 6.

[0031] The preparation method of the crown ether functionalized silica gel material comprises the following steps:

[0032] (21) 4 O)3Si(CH2) m X 1 and polyethylene polyamine NH2[C2H4NH] p-1 C2H4NH2 reacts to form silane (R 4 O)3Si(CH2) m NH[C2H4NH] p-1 C2H4NH2,X 1 It is a halogen element; R 4 Selected from C 1-22 alkyl;

[0033] (22) The silane coupling agent prepared in step (1) is added to WSi(OR 5 )3 and / or VSi(OR 6 )3, and grafted onto silica gel, or reacted with sodium silicate or tetraalkyl orthosilicate to form a silica gel precursor as shown in formula I; R 5 , R 6 Selected from C 1-22 alkyl;

[0034] (23) mixing the silica precursor obtained in step (22) and the benzocrown ether derivative having an aldehyde group represented by structural formula II in a solvent, and subjecting the mixture to a reflux reaction for a certain period of time under certain conditions;

[0035] (24) The product obtained in step (23) is reacted with a crown ether compound having an alkenyl group, a carboxyl group or a halogen group under reflux in the presence of a condensing agent, the product is filtered and washed multiple times, and then dried to obtain a crown ether functionalized silica gel material.

[0036] Furthermore, the reaction temperature of step (21) is 40-160° C., and the reaction time is 0.5-24 h; (R 4 O)3Si(CH2) m X 1 and polyethylene polyamine NH2[C2H4NH] p-1 The molar ratio of C2H4NH2 is 1:1~6; X 1 Preferred are chlorine or bromine.

[0037] Furthermore, the silica gel grafting reaction temperature in step (22) is 40-160°C, and the reaction time is 0.5-24 hours. The sol-gel reaction in step (22) is carried out under an acidic or alkaline catalyst, and the reaction temperature is 20-160°C, and the reaction time is 0.5 to 48 hours.

[0038] Furthermore, the reaction temperature in step (23) is 50-180°C, the reaction time is 2-12h; the mass ratio of the benzocrown ether derivative with an aldehyde group to the silica gel precursor is (0.01-10) mol:1g. The solvent is preferably at least one of ethanol, dimethyl sulfoxide, dichloromethane, acetonitrile, chloroform, and N,N-dimethylformamide; a catalyst is also added in step (23), and the selected catalyst is an aqueous solution of acetic acid with a concentration of 3-12M.

[0039] Furthermore, the reaction temperature in step (24) is 70-90°C, and the reaction time is 1-6h; the mass ratio of the product obtained in step (23) to the crown ether compound with an alkenyl, carboxyl or halogen group is 15-40:1. The solvent is preferably at least one of water, methanol, ethanol, dimethyl sulfoxide, dichloromethane, chloroform, and N,N-dimethylformamide. The condensation agent in step (24) is selected from any one of N,N'-azobisisobutyronitrile, 1-hydroxy-7-azobenzotriazole, 1-hydroxybenzotriazole, and N,N'-carbonyldiimidazole.

[0040] The present invention also provides an application of the crown ether functionalized silica gel material; the crown ether functionalized silica gel material can be used as an adsorbent to adsorb cesium elements, and can be specifically used for removing impurities and recovering cesium elements in nuclear waste water, chemical waste water, medical by-products, and seawater salt lakes.

[0041] The beneficial effects of the present invention are:

[0042] 1. The benzocrown ether derivative of the present invention contains four side chain groups, which are respectively connected to four silane chains to form a "four-claw" gripper that firmly clasps on the surface of silica gel, forming a "tetrahedral ion capture cage" with a regular structure. The cage structure provides an excellent spatial capture effect, which is conducive to the highly selective adsorption of cesium ions;

[0043] 2. In the present invention, the benzocrown ether exists as a key skeleton in the silica gel "capture cage" rather than a post-modified side chain, and the four-corner connection makes the crown ring of the crown ether more stable, thereby alleviating the flexibility of the crown ether;

[0044] 3. In the present invention, by regulating the polyethylene polyamine chain length, the number of crown ether modification sites on the four sides of the "capture cage" can be controlled, and crown ether side chains can be further grafted on the sides of the "capture cage" to increase the functional group loading, thus solving the problems of low loading rate and low utilization rate of the active groups of crown ether adsorbents.

[0045] 4. Benzocrown contains one or more benzene rings. The planar structure of the benzene ring reduces the steric hindrance of the side chain and enhances the chelating ability for metal ions.

[0046] The crown ether modified functionalized silica gel material of the present invention greatly improves the loading rate of the crown ether, and can realize the highly selective adsorption and separation of cesium elements in a mixed system, and the planar crown ether structure mediated by the benzene ring can promote the adsorption of Cs + The capture efficiency is further improved, which further improves the cesium adsorption capacity and selection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 It is a schematic diagram of the three-dimensional molecular cage structure of the crown ether functionalized silica gel material of the present invention.

[0048] Figure 2 Schematic diagram of the structure of the crown ether functionalized silica gel material G-1 according to an embodiment of the present invention. DETAILED DESCRIPTION

[0049] The technical solutions in the present invention will be described clearly and completely below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] The invention provides a crown ether functionalized silica gel material and a preparation method and application thereof; the crown ether functionalized silica gel material is prepared by reacting a multifunctional amino functionalized silica gel material with a benzocrown ether derivative with an aldehyde group; or by reacting a multifunctional amino functionalized silica gel material with a benzocrown ether derivative with an aldehyde group and then reacting with a crown ether compound with an alkenyl group, a carboxyl group or a halogen group.

[0051] The present invention allows the benzocrown ether derivative to react with the polyamine silane chain end amino group in the multifunctional amino-functionalized silica gel material, so that the crown ether is fixed on the silica gel material in the form of a skeleton to form a three-dimensional molecular cage structure. The formed three-dimensional molecular cage structure is as follows Figure 1 The schematic diagram is shown. In addition, the crown ether is further linked to the side of the molecular cage to increase the crown ether loading and enhance the binding effect between the material and the target substance. The crown ether functionalized silica gel material of the present invention is used as an adsorbent for cesium adsorption, which can achieve high adsorption capacity and selectivity, and has excellent cyclic regeneration ability.

[0052] The present invention will be further described below by means of specific examples.

[0053] Preparation example of crown ether derivative ligand

[0054] Preparation of crown ether derivative ligands required for the synthesis of three-dimensional molecular cage silica gel:

[0055] Dissolve dibenzo-18-crown-6 and dibenzo-24-crown-8 in acetic acid, add liquid bromine dropwise, stir and reflux at room temperature for 24 hours, filter, wash and dry, add a mixed solution of tetrahydrofuran and mesitylene (2:1) to the collected reddish brown powder, and add 4-formylphenylboronic acid pinyl alcohol, Na2CO3, distilled water and Pd(PPh3)4 at the same time. Reflux for 3 days under nitrogen protection, filter, wash and dry the product to obtain tetrasubstituted formylphenyl benzo-18-crown-6; the structural formula A of the substance is:

[0056] .

[0057] Referring to the above preparation method, dibenzo-18-crown-6 is replaced by dibenzo-21-crown-7 to obtain benzo-21-crown-7 of tetrasubstituted formylbenzoylbenzene, and the structural formula B of the substance is:

[0058] .

[0059] Referring to the above preparation method, dibenzo-18-crown-6 is replaced by dibenzo-24-crown-8 to obtain benzo-24-crown-8 of tetrasubstituted formylbenzoylbenzene, and the structural formula C of the substance is:

[0060] .

[0061] 2,3-dihydroxyterephthalaldehyde, 2-[2-(2-chloroethoxy)ethoxy]ethanol and potassium carbonate were dissolved in N,N-dimethylformamide (DMF) and heated at 80°C for 48h. The product was cooled and purified and dissolved in dichloromethane with 4-toluenesulfonyl chloride and triethanol and stirred overnight. The obtained product was dissolved in DMF again with 3,4-dihydroxybenzaldehyde and cesium carbonate and heated at 100°C for 48h. After cooling and purification, 4',5',4'',5''-tetraaldehyde dibenzo-24-crown-8 was obtained.

[0062] The product structural formula D is:

[0063] .

[0064] Example 1

[0065] In a 500mL three-necked flask, 0.4mol of diethylenetriamine and 0.4mol of (3-chloropropyl)trimethoxysilane were placed, stirred and refluxed at 120°C for 2h, and when cooled to 70°C, 50mL of methanol was added and stirred and refluxed for 1h. After cooling, the obtained reactant was put into a mixture of xylene (125ml) and spherical silica gel (100g, 200-500μm), refluxed at 150°C for 4h, filtered after cooling, washed with ethanol 5 times and dried to obtain a silica gel material shown in structural formula I.

[0066] Add the above-prepared substances A, B, and C (0.5 mol each) to three round-bottom flasks respectively, accurately weigh three portions of 10 g of the silica gel material represented by the structural formula I, dissolve them together in 100 mL of acetonitrile, and use 12 M acetic acid aqueous solution as a catalyst. After fully mixing, react at 70 ° C for 3 hours, filter, wash with ethanol several times and dry. Three crown ether functionalized silica gel materials G-1\G-2\G-3 represented by the structural formula II were prepared respectively. Among them, the structural schematic diagram of the crown ether functionalized silica gel G-1 is shown in the figure Figure 2 shown.

[0067] Application Example 1

[0068] The three crown ether functionalized silica gel materials G-1, G-2 and G-3 prepared in Example 1 were used as adsorbents. 5 g of each was added into 100 ml of 5 ppm Cs + The 1M hydrochloric acid system was shaken at room temperature for 3 hours, and the filtrate was analyzed by atomic absorption spectrometry. The results showed that the Cs + The removal rate can reach more than 90%, with good Cs + Capture capability.

[0069] In order to further compare the performance advantages of the three adsorbents, under the same experimental conditions, 0.5 g of G-1, G-2, and G-3 were weighed and placed in 50 mL of 100 ppm Cs + After 3 h of adsorption at room temperature, ICP-MS was used to measure the Cs in the supernatant. + The experimental results were analyzed and calculated, and the adsorption capacities of G-1, G-2 and G-3 were 188.11 mg g -1 , 199.27mg g -1 , 245.96mg g -1 This result shows that among the three types of crown ethers, 24-crown-8 has a stronger adsorption effect on Cs+ than the other two. This is because although 21-crown-7 is closer to the hydration radius of cesium ions among the three types of crown ethers, the dibenzo structures of 18-crown-6 and 24-crown-8 are more symmetrical, and the larger diameter of 24-crown-8 makes Cs+ + Easier to be captured, so the adsorption capacity is maximum.

[0070] Example 2

[0071] In a 500mL three-necked flask, 0.5mol of triethylenetetramine and 0.5mol of (3-chloropropyl)trimethoxysilane were placed, stirred and refluxed at 120°C for 2h, and when cooled to 70°C, 50mL of methanol was added and stirred and refluxed for 1h. After cooling, the obtained reactant was put into a mixture of xylene (125ml) and spherical silica gel (120g, 200-500μm), refluxed at 160°C for 3h, filtered after cooling, washed with ethanol 5 times and dried to obtain a silica gel material shown in structural formula I.

[0072] 0.5 mol of 4',5',4'',5''-tetraaldehyde dibenzo-24-crown-8 shown in structural formula D and 0.5 mol of benzo-24-crown-8 of tetrasubstituted formylbenzene shown in structural formula C were added to two round-bottom flasks respectively, and then 10 g of silica gel material shown in structural formula I, 100 mL of acetonitrile and 12 M acetic acid aqueous solution as catalyst were added to the two round-bottom flasks respectively. After thorough mixing, the mixture was reacted at 60°C for 4 h. After filtering, the mixture was washed several times with ethanol and dried to obtain two different crown ether functionalized silica gel materials G-4\G-5; the benzocrown ether corresponding to G-4 was 4',5',4'',5''-tetraaldehyde dibenzo-24-crown-8, and the benzocrown ether corresponding to G-5 was benzo-24-crown-8 of tetrasubstituted formylbenzene shown in structural formula C.

[0073] Application Example 2

[0074] Sr(NO3)2 and CsNO3 were dissolved in dilute nitric acid and deionized water to prepare a mixed solution with a concentration of 100 ppm for both metal ions. The adsorption performance of crown ether functionalized silica gel materials G-4 and G-5 was tested under the same conditions. The test results were calculated and analyzed, and the final results showed that the K d (Cs / Sr) = 1430, K of G-5 d (Cs / Sr) = 1302. The results show that the crown ether functionalized silica material G-4 with a smaller three-dimensional capture cage has higher cesium selectivity.

[0075] Example 3

[0076] 0.4 mol of 4'-carboxybenzo-2,4-crown-8 and 0.4 mol of 1-hydroxy-7-azobenzotriazole were mixed in advance, and added together with 10 g of the silica gel material G-4 prepared above into a three-necked flask containing 200 mL of tetrahydrofuran. The mixture was stirred and refluxed at 70°C for 1 h. The product was filtered, washed and dried to obtain a crown ether functionalized silica gel material G-6 with a further optimized structure.

[0077] Application Example 3

[0078] Will Na + , K + , Ca 2+ and Mg 2+ As Cs + The competitive ion solutions with the same concentration of 10, 50, 100 and 200 ppm were prepared for the test of the adsorption performance of crown ether functionalized silica gel material G-6. The experimental results showed that with the increase of the competitive ion concentration, Cs + The adsorption efficiency and distribution coefficient of Na+ and K + The influence of Cs is higher because the hydrated ion radii of the three are closer (Cs + :3.25 Å ,Na + :3.58 Å,k + :3.30Å); Nevertheless, the functionalized silica material G-6 has a strong affinity to CS at 200ppm. + The lowest distribution coefficient can still reach 2.5×10 4 , far exceeding other adsorbents in currently reported materials.

[0079] Example 4

[0080] 0.5 mol of 4-vinylbenzo-2,4-crown-8 and 10 g of the silica gel material G-4 prepared in Example 4 were added into a three-necked flask containing 200 mL of tetrahydrofuran, and 0.2 g of azobisisobutyronitrile was added. The mixture was refluxed at 70° C. for 4 h under nitrogen protection. The product was filtered, washed and dried to obtain crown ether functionalized silica gel material G-7.

[0081] Application Example 4

[0082] The composition of geothermal water was simulated to prepare a mixed solution with the composition shown in Table 1 below, and the pH value of the solution was adjusted to 8.8.

[0083] Table 1

[0084]

[0085] Crown ether functionalized silica gel material G-7 was used as adsorbent and placed in the above mixed solution at a solid-liquid ratio of 1:2000 for adsorption experiment. After constant temperature adsorption for 3 hours, the concentration of each ion in the solution was measured. The test results showed that when the competitive ion concentration was Cs + Under the condition of hundreds of times, the crown ether functionalized silica material G-7 has a strong affinity for Cs + The adsorption rate can still reach 98%, and the distribution coefficient can reach 12633.49. This shows that the material is suitable for the separation and capture of cesium ions in actual hot water and has significant practical application prospects.

[0086] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any modifications or equivalent transformations made using the contents of the present invention specification, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A crown ether functionalized silica gel material, characterized in that: The method is prepared by reacting a compound represented by structural formula I with a benzocrown ether derivative having an aldehyde group represented by structural formula II; wherein the terminal amino group in the compound represented by structural formula I reacts with the aldehyde group of the benzocrown ether derivative; Wherein, structural formula I is: [(O 3 / 2 )Si(CH2) m NH[C2H4NH] p-1 C2H4NH2] a [(O 4 / 2 )Si] b [VSi(O 3 / 2 )] c [WSi(O 3 / 2 )] d ; V is a substituent group selected from C 1-22 Alkyl, C 2-22 Alkenyl or C 1-22 Alkylaryl; W is a substituent group selected from C 1-20 Mercaptoalkyl, C 2-20 Alkyl sulfide group, C 1-22 Alkyl sulfide alkyl or C 2-20 Alkylene sulfide alkyl, C 2-20 Alkyl sulfide aryl, C 2-20 Alkylene sulfide aryl or C 2-6 Alkyl SC 2-6 AlkylNHC(=S)NHR 1 ; Through the silicon atoms, hydrogen, straight or branched C 1-22 Alkyl, terminal group (R 2 )3SiO 1 / 2 , cross-linking agent or chain R 2 q Si(OR 3 ) g O k / 2 or one or more of the silicon atoms of other groups in formula I saturate the free valences of the oxygen atoms of the silicate; R 1 , R 2 , R 3 Selected from linear or branched C 1-12 Alkyl, aryl or C 1-22 Alkyl aryl; k is an integer from 1 to 3, q ​​is an integer from 1 to 2, g is an integer from 0 to 2, and satisfies g+k+q=4; m is an integer from 2 to 12; p is an integer from 2 to 100; a, b, c, d are all integers, and the ratio of [a+c]:b is between 0.00001 and 100000; a and b are always present, and when c and d are greater than zero, the ratio of c+d to a+b is between 0.000001 and 100000; when end groups, crosslinking agents and / or polymer chains are present, their molar ratio to a+b+c+d is between 0 and 999:1, wherein the polymer chain is -NH[C2H4NH] p-1 C2H4NH2; Wherein, the structural formula II of the benzocrown ether derivative with an aldehyde group is one of the following structural formulas: ； wherein R1, R2, R3, R4, R1', R2', R3', R4' are selected from hydrogen, straight chain or branched C 1-12 Alkyl, C 2- C 22 Alkenyl or alkynyl, aryl or C 1-22 Alkyl aryl; T1, T2, T3, T4, T1', T2', T3', T4' may be independently present or absent, and when present, T1, T2, T3, T4, T1', T2', T3', T4' are selected from linear or branched C 1-12 Alkyl, C 2- C 22 Alkenyl or alkynyl, aryl or C 1-22 Alkylaryl; n1, n2 are integers from 1 to 6 respectively.

2. A method for preparing the crown ether functionalized silica gel material according to claim 1, characterized in that: The steps include: (11) 4 O)3Si(CH2) m X 1 and polyethylene polyamine NH2[C2H4NH] p-1 C2H4NH2 reacts to form silane (R 4 O)3Si(CH2) m NH[C2H4NH] p-1 C2H4NH2,X 1 It is a halogen element; R 4 Selected from C 1-22 alkyl; (12) Add WSi(OR) as needed to the silane coupling agent prepared in step (1) in a solvent through reflux reaction. 5 )3 and / or VSi(OR 6 )3, and grafted onto silica gel, or reacted with sodium silicate or tetraalkyl orthosilicate to form a silica gel precursor as shown in formula I; R 5 , R 6 Selected from C 1-22 alkyl; (13) The silica precursor obtained in step (12) is mixed with the benzocrown ether derivative having an aldehyde group shown in structural formula II in a solvent, and refluxed for a certain time under certain conditions. The product is filtered and washed multiple times, and then dried to obtain a crown ether functionalized silica gel material.

3. The method for preparing the crown ether functionalized silica gel material according to claim 2, characterized in that: The reaction temperature in step (13) is 50-180° C., and the reaction time is 2-12 h. The mass ratio of the benzocrown ether derivative with an aldehyde group to the silica gel precursor is (0.01-10) mol:1 g.

4. A crown ether functionalized silica gel material, characterized in that: The method is prepared by first reacting the compound represented by structural formula I with a benzocrown ether derivative having an aldehyde group represented by structural formula II, and then reacting with a crown ether compound having an alkenyl group, a carboxyl group or a halogen group; wherein the terminal amino group in the compound represented by structural formula I reacts with the aldehyde group of the benzocrown ether derivative, and the -NH- in the product after the reaction reacts with the crown ether compound having an alkenyl group, a carboxyl group or a halogen group; Wherein, structural formula I is: [(O 3 / 2 )Si(CH2) m NH[C2H4NH] p-1 C2H4NH2] a [(O 4 / 2 )Si] b [VSi(O 3 / 2 )] c [WSi(O 3 / 2 )] d ; V is a substituent group selected from C 1-22 Alkyl, C 2-22 Alkenyl or C 1-22 Alkylaryl; W is a substituent group selected from C 1-20 Mercaptoalkyl, C 2-20 Alkyl sulfide group, C 1-22 Alkyl sulfide alkyl or C 2-20 Alkylene sulfide alkyl, C 2-20 Alkyl sulfide aryl, C 2-20 Alkylene sulfide aryl or C 2-6 Alkyl SC 2-6 AlkylNHC(=S)NHR 1 ; Through the silicon atoms, hydrogen, straight or branched C 1-22 Alkyl, terminal group (R 2 )3SiO 1 / 2 , cross-linking agent or chain R 2 q Si(OR 3 ) g O k / 2 or one or more of the silicon atoms of other groups in formula I saturate the free valences of the oxygen atoms of the silicate; R 1 , R 2 , R 3 Selected from linear or branched C 1-12 Alkyl, aryl or C 1-22 Alkyl aryl; k is an integer from 1 to 3, q ​​is an integer from 1 to 2, g is an integer from 0 to 2, and satisfies g+k+q=4; m is an integer from 2 to 12; p is an integer from 2 to 100; a, b, c, d are all integers, and the ratio of [a+c]:b is between 0.00001 and 100000; a and b are always present, and when c and d are greater than zero, the ratio of c+d to a+b is between 0.000001 and 100000; when end groups, crosslinking agents and / or polymer chains are present, their molar ratio to a+b+c+d is between 0 and 999:1; The structural formula II of the benzocrown ether derivative with an aldehyde group is one of the following structural formulas: ； wherein R1, R2, R3, R4, R1', R2', R3', R4' are selected from hydrogen, straight chain or branched C 1-12 Alkyl, C 2- C 22 Alkenyl or alkynyl, aryl or C 1-22 Alkyl aryl; T1, T2, T3, T4, T1', T2', T3', T4' may be independently present or absent, and when present, T1, T2, T3, T4, T1', T2', T3', T4' are selected from linear or branched C 1-12 Alkyl, C 2- C 22 Alkenyl or alkynyl, aryl or C 1-22 Alkylaryl; n1, n2 are integers from 1 to 6 respectively.

5. A crown ether functionalized silica gel material according to claim 4, characterized in that: The structural formula III of the crown ether compound with an alkenyl group, a carboxyl group or a halogen group is one of the following structural formulas: ； X1, X2, X3, X4, X5, X6, X7, X8, X1', X2', X3', X4', X5', X6', X7', X8' are respectively selected from hydrogen, straight-chain or branched alkyl, alkenyl, alkynyl, aryl or alkylaryl, carboxyl or halogen, and in the corresponding structural formula at least one functional group is alkenyl, carboxyl or halogen, and n is 1 or 2.

6. A crown ether functionalized silica gel material according to claim 4, characterized in that: The p is an integer from 2 to 6.

7. A method for preparing the crown ether functionalized silica gel material according to any one of claims 4 to 6, characterized in that: The steps include: (21) 4 O)3Si(CH2) m X 1 and polyethylene polyamine NH2[C2H4NH] p-1 C2H4NH2 reacts to form silane (R 4 O)3Si(CH2) m NH[C2H4NH] p-1 C2H4NH2,X 1 It is a halogen element; R 4 Selected from C 1-22 alkyl; (22) The silane coupling agent prepared in step (1) is added to WSi(OR 5 )3 and / or VSi(OR 6 )3, and grafted onto silica gel, or reacted with sodium silicate or tetraalkyl orthosilicate to form a silica gel precursor as shown in formula I; R 5 , R 6 Selected from C 1-22 alkyl; (23) mixing the silica precursor obtained in step (22) and the benzocrown ether derivative having an aldehyde group represented by structural formula II in a solvent, and subjecting the mixture to a reflux reaction for a certain period of time under certain conditions; (24) The product obtained in step (23) is reacted with a crown ether compound having an alkenyl group, a carboxyl group or a halogen group under reflux in the presence of a condensing agent, the product is filtered and washed multiple times, and then dried to obtain a crown ether functionalized silica gel material.

8. The method for preparing the crown ether functionalized silica gel material according to claim 7, characterized in that: The reaction temperature in step (23) is 50-180° C., and the reaction time is 2-12 h. The mass ratio of the benzocrown ether derivative with an aldehyde group to the silica gel precursor is (0.01-10) mol:1 g.

9. The method for preparing the crown ether functionalized silica gel material according to claim 7, characterized in that: The reaction temperature in step (24) is 70-90° C., and the reaction time is 1-6 hours. The mass ratio of the product obtained in step (23) to the crown ether compound having an alkenyl group, a carboxyl group or a halogen group is 15-40:

1.

10. Use of the crown ether functionalized silica gel material according to claim 1 or claim 4, characterized in that: The crown ether functionalized silica gel material is used as an adsorbent to adsorb cesium element.

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