An amphoteric ion polymer brush P VBC / DVB Preparation and application of carbon sphere restricted access adsorbent

Abstract

The present invention relates to a zwitterionic polymer brush P VBC / DVB Preparation and application of carbon sphere restricted access adsorbent. The specific steps are as follows: using P VBC / DVB carbon spheres as the matrix, grafting polymer brushes on its surface through a two-step surface-initiated atom transfer radical polymerization technique (SI-ATRP). First, sodium 4-vinylbenzenesulfonate (Nass) and styrene (St) are grafted on the inner surface of the matrix. The polymerization of these two monomers can provide stronger hydrophobic and ion exchange interaction forces. Then, the functional monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) is grafted on the outer surface of the matrix through the SI-ATRP method to convert the material into a block polymer with a hydrophilic outer surface, obtaining a zwitterionic polymer brush restricted access adsorbent, which is used for the detection of dyes in biological samples. The raw materials of the restricted access adsorbent of the present invention are easily available. By combining the SI-ATRP technology with high grafting characteristics to graft polymer brushes, the grafting density is high, effectively improving the functional group density, thereby increasing the adsorption capacity of the adsorbent.

Description

Technical Field

[0001] The present invention belongs to the field of adsorption materials, and particularly relates to an amphoteric ion polymer brush P VBC / DVB Preparation and application of carbon sphere restricted access adsorbent. Background Art

[0002] With the rapid development of industry, the discharge of industrial wastewater has gradually increased (Literature: Y. Jiang, J. L. Gong, G. M. Zeng, X. M. Ou, Y. N. Chang, C. H. Deng, et al., Magnetic chitosan-graphene oxide composite for anti-microbial and dye removal applications, Int J Biol Macromol, 82 (2016) 702 - 710). A large amount of wastewater causes serious damage to human health and also exerts great pressure on water resources and the environment. So far, great progress has been made in the research of sewage treatment. Among them, the adsorption technology has the advantages of high cost-effectiveness, high efficiency, low energy consumption, etc., and is an ideal choice for sewage treatment.

[0003] In addition, many traditional adsorbents, including resins, activated carbon, zeolites, and biomass polymers, can fully achieve excellent adsorption capacity in wastewater purification through their porous and loose structures. However, due to the difficult regeneration process of the adsorbent, the operation is complex and the cost is high, and this method is far from ideal.

[0004] The chemical functional groups on the surface of the adsorbent determine the adsorption mechanism and adsorption selectivity, while the functional group density mainly determines the adsorption capacity. It is well known that mixed-mode adsorbents can provide multiple forces for the retention of solute molecules and can effectively improve the adsorption selectivity. Secondly, the adsorption capacity of the adsorbent is related to its specific surface area and surface group density. Therefore, an effective method to improve the adsorption capacity of the adsorbent is to adopt a new surface modification technology to connect as many functional groups as possible on the limited surface. However, due to the steric hindrance effect between polymer chains, the grafting density of polymer chains is very low, which affects the improvement of the adsorption amount (Literature: Matyjaszewski K, Tsarevsky N V. Macromolecular engineering by atom transfer radical polymerization[J]. Journal of the American Chemical Society, 2014, 136: 6513 - 6533).

[0005] Surface-initiated atom transfer radical polymerization (SI-ATRP) can graft high-density polymers because during the polymerization process, only small molecule monomers approach the chain ends of the growing chains, effectively overcoming the steric hindrance between polymer chains in the "grating to" method.

[0006] Restricted access materials (RAMs) are a type of material widely used in the analysis of complex samples in recent years. They have the dual functions of excluding macromolecular interferences such as proteins and humic substances while extracting small molecules, inhibiting non-specific adsorption between the active sites on the adsorbent and macromolecules, which may affect the adsorption performance, and can be directly applied to the separation and enrichment of small molecules in complex samples such as environmental and biological samples.

[0007] The core factors determining the performance of RAMs are: an adsorption layer with an enrichment function for small molecules and a restricted access layer on the outside that excludes macromolecules (reference: Gasparrini F, Cancelliere G, Ciogli A, et al. New chiral and restricted-access materials containing glycopeptides as selectors for the high-performance liquid chromatographic determination of chiral drugs in biological matrices[J]. Journal of Chromatography A, 2008, 1191: 205 - 213). Therefore, improving the selectivity of the adsorption layer and the exclusion effect of the restricted access layer is of great significance for the separation and enrichment of trace pollutants in complex samples such as the environment. Summary of the Invention

[0008] The present invention designs an amphoteric ion polymer brush P VBC / DVB The preparation and application of a carbon sphere restricted access adsorbent, and the technical problem to be solved is: by using SI-ATRP technology, increasing hydrophilicity and binding sites, reducing the adsorption of macromolecules such as proteins on the adsorbent surface, and effectively reducing the interference of macromolecular proteins on the enrichment analysis of small molecules.

[0009] To solve the above-mentioned existing technical problems, the present invention adopts the following solutions:

[0010] An amphoteric ion polymer brush P VBC / DVB The preparation method of a carbon sphere restricted access adsorbent, characterized in that: the amphoteric ion polymer brush P VBC / DVB The carbon sphere restricted access adsorbent is based on P VBC / DVBCarbon spheres were used as the matrix, and polymer brushes were grafted onto their surface by two-step surface initiated atom transfer radical polymerization (SI-ATRP).

[0011] The specific steps include:

[0012] Step 1: In P VBC / DVB Sodium 4-vinylbenzenesulfonate (Nass) and styrene (St) were grafted onto the inner surface of the carbon sphere matrix to obtain poly(St-co-Nass);

[0013] Step 2: Use the two-step surface initiated atom transfer radical polymerization (SI-ATRP) method to VBC / DVB The outer surface of the carbon sphere matrix is ​​grafted with a functional monomer 2-methacryloyloxyethyl phosphorylcholine (MPC), thereby converting the material into a block polymer with a hydrophilic outer surface to obtain a zwitterionic polymer brush P VBC / DVB Carbon ball limited entry adsorbent P VBC / DVB @poly(St-co-Nass)poly(MPC).

[0014] Further, in step 1, VBC / DVB The specific steps of grafting sodium 4-vinylbenzenesulfonate (Nass) and styrene (St) on the inner surface of the carbon sphere matrix to obtain poly(St-co-Nass) are as follows:

[0015] 1-2 g P VBC / DVB A carbon ball matrix, 1-2 mL of styrene St, 1-2 g of sodium 4-vinylbenzenesulfonate Nass and 0.3-0.4 g of 2,2'-bipyridine Bpy are added to a 100 mL double-necked flask, followed by adding 30-50 mL of anisole / water, wherein the volume ratio of the anisole / water is 9:1 (9:1, v / v), ultrasonically treated at a power of 100 W / L and a frequency of 40 Hz for 5 min until completely dispersed, and then the bottle mouth is closed, frozen under liquid nitrogen conditions for 5 min, vacuumed for 3 min, and nitrogen gas was passed at a flow rate of 2 L / min for 5 min. After the freezing-vacuuming-nitrogen passing process was cycled 5 times, 0.1-0.2 g of cuprous bromide CuBr was quickly added under a nitrogen atmosphere, the freezing-vacuuming-nitrogen passing process was repeated twice, and polymerization was carried out at 90° C. for 6-8 h to obtain a product;

[0016] The product obtained above was washed three times with 50 mL of anisole, 50 mL of 0.25 mol / L EDTANa2, 50 mL of water, and 50 mL of methanol in a sand core funnel, and the product was pumped with a vacuum pump until it was green-free, and vacuum dried at 60°C for 24-36 hours. After the reaction, poly(St-co-Nass) was obtained;

[0017] In step 2, the PVBC / DVB The outer surface of the carbon sphere matrix is grafted with the functional monomer 2-methacryloyloxyethyl phosphorylcholine (MPC), thereby converting the material into a block polymer with a hydrophilic outer surface, and obtaining the zwitterionic polymer brush P VBC / DVB Carbon sphere restricted access adsorbent P VBC / DVB The specific steps of @poly(St-co-Nass)poly(MPC) are as follows:

[0018] Weigh 1-2 g of the zwitterionic polymer brush P VBC / DVB Carbon sphere restricted access adsorbent P VBC / DVB @poly(St-co-Nass) into a two-necked flask, add 0.4-0.5 g of 2,2'-bipyridine Bpy, 1-2 g of the monomer 2-methacryloyloxyethyl phosphorylcholine MPC, 20-30 mL of anisole C7H8O, after ultrasonic treatment for 5 min at a power of 100 W / L and a frequency of 40 Hz, freeze for 5 min under liquid nitrogen conditions, evacuate for 3 min, and pass nitrogen at a flow rate of 2 L / min for 5 min. After cycling 5 times, quickly add 0.1-0.2 g of copper(I) bromide CuBr, repeat the freeze-evacuate-pass nitrogen process 2 times, and react at 40 °C for 24-36 h;

[0019] After the reaction, wash 3 times with 50 mL of anisole C7H8O, 50 mL of 0.25 mol / L EDTA Na2, 50 mL of water, and 50 mL of methanol in sequence;

[0020] The product is vacuum dried at 60 °C for 24-36 h to obtain the product with the outer surface grafted with the functional monomer 2-methacryloyloxyethyl phosphorylcholine MPC, and obtain the zwitterionic polymer brush restricted access adsorbent P VBC / DVB @poly(St-co-Nass)poly(MPC).

[0021] Furthermore, for the zwitterionic polymer brush restricted access adsorbent P VBC / DVB The preparation process of the carbon sphere matrix is as follows:

[0022] Using 4-vinylbenzyl chloride (VBC) and divinylbenzene (DVB) as monomers, polyvinyl alcohol as a dispersant, and azobisisobutyronitrile (AIBN) as an initiator, prepare P VBC / DVB spheres, and obtain P VBC / DVB spheres after carbonization and activation to obtain P VBC / DVB Carbon sphere matrix.

[0023] Furthermore, for the zwitterionic polymer brush restricted access adsorbent P VBC / DVB The preparation process of the carbon sphere matrix is operated according to the following specific steps:

[0024] (1) P VBC / DVBPreparation of spheres:

[0025] Weigh 1 - 2 g of polyvinyl alcohol, 0.5 - 1 g of gelatin, and 4 - 5 g of sodium chloride in sequence, dissolve them in 150 mL of deionized water, and mechanically stir at 200 - 300 rpm for 1 h under the condition of 80 °C until completely dissolved. After obtaining a clear aqueous phase mixed solution A, cool it to room temperature;

[0026] Weigh 15 - 20 mL of 4 - vinylbenzyl chloride (VBC), 10 - 15 mL of divinylbenzene (DVB), 10 - 15 mL of toluene, 40 - 45 mL of dibutyl phthalate, and 0.5 - 1 g of azobisisobutyronitrile (AIBN). After mixing evenly, ultrasonically dissolve it for 5 min under the conditions of a power of 100 W / L and a frequency of 40 Hz to obtain an oil phase mixed solution B;

[0027] Mix the aqueous phase mixed solution A and the oil phase mixed solution B, and heat at 70 °C for 8 - 12 h; after the reaction is completed, wash it 3 times with 50 mL of ethanol and 50 mL of water in sequence, and after washing, dry it in vacuum at 50 °C for 8 - 12 h to obtain P VBC / DVB spheres;

[0028] (2) Carbonization and activation of P VBC / DVB spheres:

[0029] Place 20 - 30 g of P VBC / DVB spheres obtained in step (1) into a tubular furnace, heat it to 400 °C at a heating rate of 2.5 °C / min, and keep it for 4 - 6 h; then cool it to room temperature at a rate of 2.5 °C / min to obtain carbonized P VBC / DVB carbon spheres;

[0030] Place 10 - 15 g of carbonized P VBC / DVB carbon spheres into a tubular furnace, heat it to 800 °C under the protection of nitrogen at a flow rate of 100 mL / min, and the heating rate is 2.5 °C / min; adjust the nitrogen flow rate to 50 mL / min and the water vapor flow rate to 12 mL / min, and keep it at the required activation temperature for 3 - 6 h, then cool it to room temperature at a rate of 2.5 °C / min to obtain activated P VBC / DVB carbon spheres.

[0031] Furthermore, the P VBC / DVB carbon sphere matrix of the restricted access adsorbent is spherical, specifically P VBC / DVB carbon spheres with a particle size of 400 - 800 μm.

[0032] The present invention also protects an amphoteric ion polymer brush P VBC / DVB restricted access adsorbent of amphoteric ion polymer brush prepared by the preparation method of the carbon sphere restricted access adsorbent.

[0033] The present invention also protects an amphoteric ion polymer brush PVBC / DVB Application of Carbon Sphere Restricted Access Adsorbent in Detection of Dyes in Biological Samples

[0034] The present invention has the following beneficial effects:

[0035] 1. Specifically, the present invention uses suspension polymerization method to prepare P spheres with VBC and DVB as monomers and AIBN as initiator, and obtains P carbon spheres after carbonization and activation. This preparation method is simple in operation, easy to control temperature, has a large specific surface area of the product and regular shape. VBC / DVB sphere, and obtain P VBC / DVB carbon spheres after carbonization and activation. This preparation method is simple in operation, easy to control temperature, has a large specific surface area of the product and regular shape.

[0036] 2. The present invention grafts polymer brushes by two-step SI-ATRP technology. First, Nass and St are grafted on the inner surface of the matrix. The polymerization of the two monomers can provide stronger hydrophobic interaction and ion exchange force. Then, the functional monomer MPC is grafted on the outer surface by SI-ATRP method to convert the material into a block polymer with hydrophilic outer surface, and the zwitterionic polymer brush restricted access adsorbent P VBC / DVB @poly(St-co-Nass)poly(MPC) is obtained.

[0037] The zwitterionic polymer brush P VBC / DVB carbon sphere restricted access adsorbent involved in the present invention has cheap and easily available raw materials for preparation. By using SI-ATRP technology, hydrophilicity and binding sites can be increased. The polymerization of St and Nass monomers can provide stronger hydrophobic interaction and ion exchange force.

[0038] 3. In the present invention, the functional monomer 2-methacryloyloxyethyl phosphorylcholine MPC is used as the restricted access material. It has a bilayer structure, with both an inner surface extraction layer for extracting small molecule analytes and an outer surface exclusion layer for excluding macromolecules such as proteins. It can reduce the adsorption of macromolecules such as proteins on the surface of the adsorbent and effectively reduce the interference of macromolecular proteins on the enrichment analysis of small molecules. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 . Schematic diagram of the synthesis of the zwitterionic polymer brush P VBC / DVB carbon sphere restricted access adsorbent P VBC / DVB @poly(St-co-Nass)poly(MPC) in Example 1 of the present invention.

[0040] Figure 2 . Electron micrograph and actual image of P VBC / DVB carbon spheres in Example 1 of the present invention.

[0041] Figure 3 . Schematic diagram of measuring the specific surface area and pore size of P VBC / DVB carbon spheres by N2 isothermal adsorption instrument (BET) in Example 1 of the present invention.

[0042] Figure 4 . Use the Coomassie brilliant blue G-250 method to explore the zwitterionic polymer brush P in Example 1 of the present invention VBC / DVB Schematic diagram of the protein exclusion performance of the carbon sphere restricted access adsorbent.

[0043] Figure 5 . Before and after six dye solutions are adsorbed by the zwitterionic polymer brush P in Example 1 of the present invention VBC / DVB Change diagram of the ultraviolet peak absorption intensity of the dye in the solution before and after adsorption by the carbon sphere restricted access adsorbent.

[0044] Figure 6 . The zwitterionic polymer brush P in Example 1 of the present invention VBC / DVB Carbon sphere restricted access adsorbent P VBC / DVB Adsorption isotherms (A) and kinetic adsorption curves (B) of @poly(St-co-Nass)poly(MPC) for 6 different dyes.

[0045] Figure 7 . The zwitterionic polymer brush P in Example 1 of the present invention VBC / DVB Schematic diagram of the results of the cyclic regeneration test of the carbon sphere restricted access adsorbent for dye adsorption. Detailed implementation mode

[0046] In order to make the purpose, technical solution and advantages of the present invention clearer, the following further details the present invention in combination with specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and do not constitute a limitation to the present invention.

[0047] Example 1

[0048] The specific preparation method of the zwitterionic polymer brush P and the carbon sphere restricted access adsorbent of the present invention is as follows: VBC / DVB The specific preparation steps are as follows:

[0049] First: The zwitterionic polymer brush P VBC / DVB Specific preparation steps of the carbon sphere restricted access adsorbent

[0050] Step 1: The specific steps for grafting sodium 4-vinylbenzenesulfonate (Nass) and styrene (St) on the inner surface of the P VBC / DVB carbon sphere matrix to obtain poly(St-co-Nass) are as follows:

[0051] Graft poly(St-co-Nass) on the surface of the P VBC / DVB carbon sphere by SI-ATRP method: Add 1.0 g of P VBC / DVBCarbon spheres, 1.2 mL of styrene (St), 1.0 g of sodium 4-vinylbenzenesulfonate (Nass), and 0.312 g of 2,2'-bipyridine (Bpy) were added to a 100 mL two-necked flask. Subsequently, 30 mL of anisole / water (9:1, v / v) was added, and the mixture was sonicated for 5 min at a power of 100 W / L and a frequency of 40 Hz until completely dispersed. Then, the flask was sealed, frozen under liquid nitrogen conditions for 5 min, evacuated for 3 min, purged with nitrogen at a flow rate of 2 L / min for 5 min, and the freeze-evacuate-purge cycle was repeated 5 times. After that, 0.143 g of copper(I) bromide (CuBr) was quickly added under a nitrogen atmosphere, and the freeze-evacuate-purge cycle was repeated 2 times. Then, the polymerization reaction was carried out at 90 °C for 6 h to obtain the product;

[0052] The obtained product was washed successively 3 times with 50 mL of anisole, 50 mL of 0.25 mol / L EDTA Na2, 50 mL of water, and 50 mL of methanol in a sintered glass funnel, and then suctioned with a vacuum pump until no green color remained. It was then dried in vacuo at 60 °C for 24 h, and poly(St-co-Nass) was obtained after the reaction;

[0053] Step 2: Then, through a two-step surface-initiated atom transfer radical polymerization (SI-ATRP) method, the functional monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) was grafted onto the outer surface of the carbon sphere matrix, thereby converting the material into a block polymer with a hydrophilic outer surface, and an amphiphilic ionomer brush P VBC / DVB Carbon sphere restricted access adsorbent was obtained. The specific steps are as follows: VBC / DVB 1 g of the amphiphilic ionomer brush P

[0054] @poly(St-co-Nass) obtained in Step 1 was weighed and placed in a two-necked flask. 0.42 g of 2,2'-bipyridine (Bpy), 1.6 g of the monomer 2-methacryloyloxyethyl phosphorylcholine (MPC), and 20 mL of anisole (C7H8O) were added. After sonication for 5 min at a power of 100 W / L and a frequency of 40 Hz, the mixture was frozen under liquid nitrogen conditions for 5 min, evacuated for 3 min, purged with nitrogen at a flow rate of 2 L / min for 5 min, and the cycle was repeated 5 times. Then, 0.13 g of copper(I) bromide (CuBr) was quickly added, and the freeze-evacuate-purge cycle was repeated 2 times. The reaction was carried out at 40 °C for 24 h. VBC / DVB Carbon sphere restricted access adsorbent P VBC / DVB After the reaction, it was washed successively 3 times with 50 mL of anisole (C7H8O), 50 mL of 0.25 mol / L EDTA Na2, 50 mL of water, and 50 mL of methanol.

[0055] It was dried in vacuo at 60 °C for 24 h to obtain the product with the functional monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) grafted onto the outer surface, and a novel amphiphilic ionomer brush restricted access adsorbent P

[0056] ​VBC / DVB @poly(St-co-Nass) poly(MPC).

[0057] Secondly, regarding P VBC / DVB Preparation method of carbon sphere matrix:

[0058] (1) Preparation of P VBC / DVB Spheres:

[0059] Weigh 1.5 g of polyvinyl alcohol, 0.5 g of gelatin, and 4 g of sodium chloride in sequence and dissolve them in 150 mL of deionized water. Stir mechanically at 200 rpm for 1 h under the condition of 80 °C until completely dissolved. After obtaining a clear aqueous phase mixed solution A, cool it to room temperature.

[0060] Weigh 15 mL of VBC, 10 mL of DVB, 10 mL of toluene, 40 mL of dibutyl phthalate, and 0.5 g of AIBN. After mixing evenly, ultrasonic dissolve for 5 min under the conditions of a power of 100 W / L and a frequency of 40 Hz to obtain an oil phase mixed solution B

[0061] Mix the aqueous phase mixed solution A and the oil phase mixed solution B, and heat at 70 °C for 8 h.

[0062] After the reaction is completed, wash 3 times with 50 mL of ethanol and 50 mL of water in sequence, and vacuum dry at 50 °C for 8 h to obtain P VBC / DVB Spheres.

[0063] (2) Carbonization and activation of P VBC / DVB Spheres:

[0064] Put 20 g of P VBC / DV Spheres obtained in step (1) into a tube furnace, heat up to 400 °C at a heating rate of 2.5 °C / min, and keep it for 4 h. Then cool down at a rate of 2.5 °C / min. Obtain carbonized P VBC / DVB Carbon spheres.

[0065] Put 10.0 g of the obtained carbonized P VBC / DVB Spheres into a tube furnace, heat to 800 °C under the protection of nitrogen at a flow rate of 100 mL / min, with a heating rate of 2.5 °C / min. Adjust the nitrogen flow rate to 50 mL / min and the water vapor flow rate to 12 mL / min, and keep it at the required activation temperature for 3 h. Then cool down to room temperature at a rate of 2.5 °C / min to obtain the activated P VBC / DVB Carbon sphere matrix.

[0066] Example 2

[0067] First: Preparation steps of zwitterionic polymer brush P VBC / DVB Carbon sphere restricted access adsorbent

[0068] Step 1: On the inner surface of the P VBC / DVB The specific steps for grafting sodium 4-vinylbenzenesulfonate (Nass) and styrene (St) onto the inner surface of the carbon sphere matrix to obtain poly(St-co-Nass) are as follows:

[0069] Using SI-ATRP method to graft poly(St-co-Nass) onto the surface of P VBC / DVB Carbon spheres: Add 2.0 g of P VBC / DVB Carbon spheres, 2 mL of styrene St, 2.0 g of sodium 4-vinylbenzenesulfonate Nass, and 0.4 g of 2,2'-bipyridine Bpy into a 100 mL two-necked flask. Then add 50 mL of anisole / water (9:1, v / v), ultrasonically treat for 5 min at a power of 100 W / L and a frequency of 40 Hz until completely dispersed, then seal the bottle mouth. Freeze for 5 min under liquid nitrogen conditions, evacuate for 3 min, and purge with nitrogen at a flow rate of 2 L / min for 5 min. Repeat the freeze-evacuate-purge with nitrogen process 5 times. Then quickly add 0.2 g of copper(I) bromide CuBr under a nitrogen atmosphere, repeat the freeze-evacuate-purge with nitrogen process 2 times, and polymerize at 90 °C for 8 h to obtain the product;

[0070] The obtained product is washed 3 times successively with 50 mL of anisole, 50 mL of 0.25 mol / L EDTANa2, 50 mL of water, and 50 mL of methanol in a sintered glass funnel, and pumped with a vacuum pump until there is no green color. Dry in vacuum at 60 °C for 36 h, and poly(St-co-Nass) is obtained after the reaction;

[0071] Step 2: Then, through a two-step surface-initiated atom transfer radical polymerization (SI-ATRP) method, graft the functional monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) onto the outer surface of the P VBC / DVB Carbon sphere matrix to convert the material into a block polymer with a hydrophilic outer surface, and obtain the zwitterionic polymer brush P VBC / DVB The specific steps for the carbon sphere restricted access adsorbent are as follows:

[0072] Weigh 2 g of the zwitterionic polymer brush P VBC / DVB Carbon sphere restricted access adsorbent P VBC / DVB @poly(St-co-Nass) into a two-necked flask, add 0.5 g of 2,2'-bipyridine Bpy, 2.0 g of the monomer 2-methacryloyloxyethyl phosphorylcholine MPC, and 30 mL of anisole C7H8O. Ultrasonically treat for 5 min at a power of 100 W / L and a frequency of 40 Hz, then freeze for 5 min under liquid nitrogen conditions, evacuate for 3 min, and purge with nitrogen at a flow rate of 2 L / min for 5 min. After 5 cycles, quickly add 0.2 g of copper(I) bromide CuBr, repeat the freeze-evacuate-purge with nitrogen process 2 times, and react at 40 °C for 36 h.

[0073] After the reaction, it was washed three times successively with 50 mL of anisole (C7H8O), 50 mL of 0.25 mol / L EDTA Na2, 50 mL of water, and 50 mL of methanol.

[0074] It was dried under vacuum at 60 °C for 36 h to obtain a product with the functional monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) grafted on the outer surface, and a novel zwitterionic polymer brush restricted access adsorbent P was obtained. VBC / DVB @poly(St-co-Nass)poly(MPC).

[0075] Secondly, regarding P VBC / DVB Preparation method of carbon sphere matrix:

[0076] (1) Preparation of P VBC / DVB Spheres:

[0077] Weigh 2.0 g of polyvinyl alcohol, 1.0 g of gelatin, and 5 g of sodium chloride and dissolve them in 150 mL of deionized water. Under the condition of 80 °C, stir mechanically at 300 rpm for 1 h until completely dissolved. After obtaining a clear aqueous phase mixed solution A, it was cooled to room temperature.

[0078] Weigh 20 mL of VBC, 15 mL of DVB, 15 mL of toluene, 45 mL of dibutyl phthalate, and 1.0 g of AIBN. After mixing evenly, ultrasonically dissolve it for 5 min under the conditions of a power of 100 W / L and a frequency of 40 Hz to obtain an oil phase mixed solution B.

[0079] Mix the aqueous phase mixed solution A and the oil phase mixed solution B, and heat at 70 °C for 12 h.

[0080] After the reaction is completed, wash it three times successively with 50 mL of ethanol and 50 mL of water, and dry it under vacuum at 50 °C for 12 h to obtain P VBC / DVB Spheres.

[0081] (2) Carbonization and activation of P VBC / DVB Spheres:

[0082] Put 30 g of P VBC / DV B spheres obtained in step (1) into a tubular furnace, heat it up to 400 °C at a heating rate of 2.5 °C / min, and keep it at this temperature for 6 h. Then cool it down at a rate of 2.5 °C / min. Obtain carbonized P VBC / DVB Carbon spheres.

[0083] The obtained carbonized P VBC / DVBA 15.0 g ball is placed in a tubular furnace and heated to 800 °C under nitrogen protection at a flow rate of 100 mL / min. The heating rate is 2.5 °C / min. The nitrogen flow rate is adjusted to 50 mL / min, and the water vapor flow rate is 12 mL / min and maintained at the required activation temperature for 6 h. Then, it is cooled to room temperature at a rate of 2.5 °C / min to obtain activated P VBC / DVB Carbon sphere matrix.

[0084] Example 3

[0085] First: Zwitterionic polymer brush P VBC / DVB Specific steps for the preparation of carbon sphere restricted access adsorbent

[0086] Step 1: The specific steps for grafting sodium 4-vinylbenzenesulfonate (Nass) and styrene (St) on the inner surface of the P VBC / DVB carbon sphere matrix to obtain poly(St-co-Nass) are as follows:

[0087] Using SI-ATRP method to graft poly(St-co-Nass) on the surface of P VBC / DVB carbon sphere: Add 1.4 g of P VBC / DVB carbon spheres, 1.5 mL of styrene St, 1.5 g of sodium 4-vinylbenzenesulfonate Nass and 0.3 g of 2,2'-bipyridine Bpy into a 100 mL two-necked flask. Then add 40 mL of anisole / water (9:1, v / v), sonicate for 5 min at a power of 100 W / L and a frequency of 40 Hz until completely dispersed, then seal the bottle mouth, freeze for 5 min under liquid nitrogen conditions, evacuate for 3 min, and pass nitrogen at a flow rate of 2 L / min for 5 min. The freeze-evacuate-pass nitrogen process is repeated 5 times. Then, quickly add 0.1 g of copper(I) bromide CuBr under nitrogen atmosphere, repeat the freeze-evacuate-pass nitrogen process 2 times, and carry out polymerization reaction at 90 °C for 7 h to obtain the product;

[0088] The obtained product is washed 3 times with 50 mL of anisole, 50 mL of 0.25 mol / L EDTANa2, 50 mL of water, and 50 mL of methanol in a sintered funnel, and pumped to no green color with a vacuum pump, and vacuum dried at 60 °C for 30 h. After the reaction, poly(St-co-Nass) is obtained;

[0089] Step 2: Then, through a two-step surface-initiated atom transfer radical polymerization technique (SI-ATRP method), graft the functional monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) on the outer surface of the P VBC / DVB carbon sphere matrix, thereby converting the material into a block polymer with a hydrophilic outer surface, and obtaining the zwitterionic polymer brush P VBC / DVB carbon sphere restricted access adsorbent. The specific steps are as follows:

[0090] Weigh 1.2 g of the zwitterionic polymer brush P obtained in Step 1 VBC / DVB Carbon sphere restricted access adsorbent P VBC / DVB @poly(St-co-Nass) into a two-necked flask, add 0.4 g of 2,2'-bipyridine Bpy, 1.0 g of monomer 2-methacryloyloxyethyl phosphorylcholine MPC, 25 mL of anisole C7H8O, and ultrasonically treat for 5 min at a power of 100 W / L and a frequency of 40 Hz. Then freeze for 5 min under liquid nitrogen conditions, evacuate for 3 min, and purge with nitrogen at a flow rate of 2 L / min for 5 min. After repeating this cycle 5 times, quickly add 0.1 g of copper(I) bromide CuBr, and repeat the freeze-evacuate-purge with nitrogen process 2 times. React at 40 °C for 30 h.

[0091] After the reaction is completed, wash it successively 3 times with 50 mL of anisole C7H8O, 50 mL of 0.25 mol / L EDTA Na2, 50 mL of water, and 50 mL of methanol.

[0092] Dry it under vacuum at 60 °C for 30 h to obtain a product with the functional monomer 2-methacryloyloxyethyl phosphorylcholine MPC grafted on the outer surface, and obtain a novel zwitterionic polymer brush restricted access adsorbent P VBC / DVB @poly(St-co-Nass)poly(MPC).

[0093] Secondly, regarding P VBC / DVB Preparation method of carbon sphere matrix:

[0094] (1) Preparation of P VBC / DVB Spheres:

[0095] Weigh 1.0 g of polyvinyl alcohol, 0.8 g of gelatin, and 4.5 g of sodium chloride and dissolve them in 150 mL of deionized water. Stir mechanically at 200 rpm for 1 h at 80 °C until completely dissolved to obtain a clear aqueous phase mixed solution A, and then cool to room temperature.

[0096] Weigh 16 mL of VBC, 12 mL of DVB, 12 mL of toluene, 43 mL of dibutyl phthalate, and 0.6 g of AIBN. Mix them evenly and ultrasonically dissolve for 5 min at a power of 100 W / L and a frequency of 40 Hz to obtain an oil phase mixed solution B

[0097] Mix the aqueous phase mixed solution A and the oil phase mixed solution B, and heat at 70 °C for 10 h.

[0098] After the reaction is completed, wash it successively 3 times with 50 mL of ethanol and 50 mL of water, and dry it under vacuum at 50 °C for 10 h to obtain P VBC / DVB Spheres.

[0099] (2) Carbonization and activation of P VBC / DVB of Spheres:

[0100] Place the 25 g of P obtained in step (1) VBC / DV B spheres into a tube furnace, heat it to 400 °C at a heating rate of 2.5 °C / min, and hold for 5 h. Then cool it at a rate of 2.5 °C / min. Obtain carbonized P VBC / DVB carbon spheres.

[0101] Place 12.0 g of the obtained carbonized P VBC / DVB spheres into a tube furnace, heat it to 800 °C under nitrogen protection at a flow rate of 100 mL / min, with a heating rate of 2.5 °C / min, adjust the nitrogen flow rate to 50 mL / min, the water vapor flow rate to 12 mL / min, and hold at the required activation temperature for 5 h. Then cool it to room temperature at a rate of 2.5 °C / min to obtain the activated P VBC / DVB carbon sphere matrix.

[0102] Regarding the zwitterionic polymer brush P of the present invention VBC / DVB protein exclusion performance experiment of carbon sphere restricted access adsorbent

[0103] The protein exclusion characteristics were investigated by measuring the adsorption experiment of bovine serum albumin (BSA) by Coomassie Brilliant Blue G-250 method.

[0104] Add 10 mL of Coomassie Brilliant Blue to 0.5 mL of 0, 0.2, 0.4, 0.6, 0.8, and 1 mg mL -1 BSA standard solutions. After 10 min, measure the absorbance of the solution at 595 nm. Fit the BSA concentration against the absorbance to obtain the standard curve of the BSA solution. Disperse 10.0 mg of P VBC / DVB 、P VBC / DVB @poly(St-co-Nass) and P VBC / DVB @poly(St-co-Nass)poly(MPC) separately in 5.0 mL of BSA solutions with different concentrations (0.1 - 5.0 g L -1 ) in centrifuge tubes. Take 0.5 mL of the eluent into the centrifuge tube, add 10 mL of Coomassie Brilliant Blue, let it stand for 10 min, and then detect the absorbance of BSA at 595 nm with a UV-visible spectrophotometer.

[0105] Regarding the zwitterionic polymer brush P of the present invention VBC / DVB dye adsorption experiment of carbon sphere restricted access adsorbent

[0106] The adsorption performance of P VBC / DVB @poly(St-co-Nass)poly(MPC) was studied by static adsorption experiment.

[0107] Weigh 10 mg of the adsorbent and add it to 10 mL of dye solutions with different concentrations. After shaking for a certain time at room temperature, separate the adsorbent, and the obtained supernatant is filtered through a 0.22 μm filter membrane. Then, the concentrations of the dye before and after adsorption are measured by ultraviolet, and the adsorption capacity is calculated.

[0108] The adsorption rate of P VBC / DVB @poly(St-co-Nass)poly(MPC) was studied through dynamic adsorption experiments.

[0109] Weigh 10 mg of P VBC / DVB @poly(St-co-Nass)poly(MPC) and add it to 10 mL of the dye solution. Shake it at room temperature for 30 - 720 min. Separate the adsorbent by centrifuge, and the obtained supernatant is filtered through a 0.22 μm filter membrane. Then, the concentrations of the dye before and after adsorption are measured by ultraviolet, and the adsorption capacity is calculated.

[0110] Regarding the zwitterionic polymer brush P VBC / DVB Recycling experiment of the carbon sphere restricted access adsorbent

[0111] Add 20 mg of the adsorbent to 100 mL of the dye solution. After shaking for a period of time, centrifuge the obtained adsorbent and wash it ultrasonically with 0.1 mol L -1 HCl and methanol for multiple times. Then dry the regenerated adsorbent in a vacuum oven at 60 °C and conduct cyclic adsorption experiments to investigate the recycling performance of this material.

[0112] Regarding the zwitterionic polymer brush P VBC / DVB Synthesis and characterization of the carbon sphere restricted access adsorbent:

[0113] Figure 1 For the zwitterionic polymer brush P VBC / DVB Carbon sphere restricted access adsorbent P VBC / DVB @poly(St-co-Nass)poly(MPC) preparation schematic diagram.

[0114] P VBC / DVB Carbon spheres were prepared by suspension polymerization. First, graft St and Nass monomers by SI-ATRP method to form a polymer brush, and then graft MPC by SI-ATRP method again to finally obtain the novel restricted access adsorbent P VBC / DVB @poly(St-co-Nass)poly(MPC).

[0115] Figure 2 For P VBC / DVB Electron microscope image and actual image of the carbon sphere in Example 1.

[0116] As Figure 2As shown in (A - B), it can be seen by SEM that P VBC / DVB carbon spheres are of uniform size and have a relatively smooth surface. By Figure 2 (C - D), it can be clearly seen that after carbonization, P VBC / DVB carbon spheres (right) have a smaller particle size than P VBC / DVB spheres (left) before carbonization and their color has changed to black, proving the success of carbonization activation. By Figure 2 (E - F), it can be directly observed that P VBC / DVB carbon spheres have a particle size of approximately 400 - 800 μm, regular shape, and are uniformly circular.

[0117] Figure 3 Figure for measuring the specific surface area and pore size of P VBC / DVB carbon spheres in Example 1 by N2 isothermal adsorption instrument (BET).

[0118] P VBC / DVB carbon spheres show a type I N2 isotherm, with a specific surface area of 1993.26 m 2 / g, a pore volume of 0.27 cm 3 / g, and an average pore size of 3.1 nm (Table 1).

[0119] Table 1

[0120]

[0121] Application of zwitterionic polymer brush P VBC / DVB carbon sphere restricted access adsorbent of the present invention

[0122] (1) Exploration of protein exclusion performance of materials

[0123] The Coomassie Brilliant Blue G - 250 method was used to study the exclusion rate of P VBC / DVB @poly(St - co - Nass)poly(MPC) for bovine serum albumin (BSA). Figure 4 Figure for exploring the protein exclusion performance of the zwitterionic polymer brush P VBC / DVB carbon sphere restricted access adsorbent in Example 1 of the present invention by the Coomassie Brilliant Blue G - 250 method.

[0124] From Figure 4 it can be seen that the exclusion rate of P VBC / DVB @poly(St - co - Nass)poly(MPC) in Example 1 for BSA reaches 96.56%, while the exclusion rates of P VBC / DVB microspheres without grafted MPC and P VBC / DVB @poly(St - co - Nass) are only 34.78% and 39.45% respectively, which shows that P VBC / DVB@poly(St-co-Nass)poly(MPC) has an exclusion ability for proteins because after MPC is grafted onto the surface of P VBC / DVB @poly(St-co-Nass), the outer surface of the microspheres becomes hydrophilic. Therefore, the exclusion rate of P VBC / DVB @poly(St-co-Nass)poly(MPC) is higher than that of P VBC / DVB @poly(St-co-Nass).

[0125] (2) The zwitterionic polymer brush P of the present invention VBC / DVB Carbon sphere restricted access adsorbent P VBC / DVB @poly(St-co-Nass)poly(MPC) Application in the adsorption of dyes

[0126] The adsorption properties of 6 dyes, methylene blue (MB), basic fuchsin (BF), neutral red (NR), congo red (CR), acid fuchsin (AF) and methyl orange (MO), were studied through single dye adsorption experiments.

[0127] Figure 5 For the zwitterionic polymer brush P in Example 1 of the present invention VBC / DVB The carbon sphere restricted access adsorbent dye was adsorbed by P VBC / DVB @poly(St-co-Nass)poly(MPC) The UV-visible spectrum after adsorption. The UV-visible spectra of 6 dye solutions all showed a strong absorption peak before adsorption. After adding the adsorbent P VBC / DVB @poly(St-co-Nass)poly(MPC), the absorbance intensities of MB and BF decreased significantly, and the color of the solution became significantly lighter. For NR, CR, acid MO and AF, the peak intensity of the UV-visible spectrum adsorbed by P VBC / DVB @poly(St-co-Nass)poly(MPC) did not decrease significantly.

[0128] The adsorption performance of materials is the main reference index for their use as adsorbents. The static adsorption process was explored. The adsorption capacities of 6 dyes at different concentrations were studied. Figure 6 For the zwitterionic polymer brush PVBC / DVB carbon sphere restricted access adsorbent PVBC / DVB@poly(St-co-Nass)poly(MPC) in Example 1 of the present invention, the adsorption isotherm (A) and kinetic adsorption curve (B) of 6 different dyes.

[0129] From Figure 6It is known from A that the adsorption capacities of the 6 dyes (BF, NR, MB, MO, CR, AF) all increase with the increase of concentration and finally tend to be balanced, being 310, 215, 180, 138, 108 and 90 mg / g respectively.

[0130] The speed at which the material reaches adsorption equilibrium is also an important index for studying the material as an adsorbent. Therefore, the adsorption kinetics process was also studied. With the initial concentration of the dye being 200 mg / L, the influence of adsorption time on the adsorption capacities of the 6 dyes was studied.

[0131] It is known from Figure 6 B that the adsorption capacities of the 6 dyes all increase first and then tend to be saturated with the prolongation of contact time. In the initial stage of adsorption, the adsorption rate of the dye is significantly accelerated because there are a large number of active sites on the surface of the material in the initial stage. The adsorption equilibrium times of dyes BF, NR, MB, MO, CR, AF are 120, 360, 480, 240, 120 and 360 min respectively.

[0132] (3) The zwitterionic polymer brush P of the present invention VBC / DVB Cyclic regeneration test of the carbon sphere restricted access adsorbent for dye adsorption

[0133] The adsorbent loaded with the dye was eluted with 0.1 mol·L -1 hydrochloric acid and methanol and then used for testing the recovery rate of the dye again. Figure 7 is the schematic diagram of the cyclic regeneration test result of the zwitterionic polymer brush P VBC / DVB carbon sphere restricted access adsorbent for dye adsorption in Example 1 of the present invention. It can be seen from Figure 7 that after 7 consecutive cycles, the material still has good adsorption capacity. The recovery rates of MB and BF are only reduced by 5.81% and 6.84% compared with the first time, indicating that the material has good recyclability and stability.

[0134] The zwitterionic polymer brush P VBC / DVB carbon sphere restricted access adsorbent involved in the present invention has cheap and easily available preparation raw materials. By using the SI-ATRP technology, the hydrophilicity and binding sites can be increased. The polymerization of the two monomers St and Nass can provide stronger hydrophobic interaction and ion exchange force.

[0135] In the present invention, the functional monomer 2-methacryloyloxyethyl phosphorylcholine MPC is used as the restricted access material. It has a bilayer structure, with both an inner surface extraction layer for the extraction function of small molecule analytes and an outer surface exclusion layer for the exclusion function of macromolecules such as proteins. It can reduce the adsorption of macromolecules such as proteins on the surface of the adsorbent and effectively reduce the interference of macromolecular proteins on the enrichment analysis of small molecules.

[0136] The present invention has been described exemplarily in connection with the embodiments. Obviously, the implementation of the present invention is not limited by the above-mentioned manner. As long as various improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. Zwitterionic polymer brush P VBC / DVB Preparation method of carbon sphere restricted access adsorbent, characterized in that: The zwitterionic polymer brush P VBC / DVB The carbon sphere restricted access adsorbent uses P VBC / DVB The carbon sphere as the matrix, and grafts the polymer brush on its surface through the two-step surface-initiated atom transfer radical polymerization technique SI-ATRP; Specifically, the following steps are included: Step 1: Graft sodium 4-vinylbenzenesulfonate (Nass) and styrene (St) onto the inner surface of the carbon sphere matrix to obtain poly(St-co-Nass); VBC / DVB ​ Step 2: Then, through a two-step surface-initiated atom transfer radical polymerization (SI-ATRP) method, graft the functional monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) onto the outer surface of the P VBC / DVB carbon sphere matrix, thereby converting the material into a block polymer with a hydrophilic outer surface, and obtaining an amphoteric ion polymer brush P VBC / DVB carbon sphere restricted access adsorbent P VBC / DVB @poly(St-co-Nass)poly(MPC); P of the zwitterionic polymer brush restricted access adsorbent described above VBC / DVB The preparation process of the carbon sphere matrix is as follows: Using 4-vinylbenzyl chloride (VBC) and divinylbenzene (DVB) as monomers, polyvinyl alcohol as a dispersant, and azobisisobutyronitrile (AIBN) as an initiator, P was prepared by suspension polymerization VBC / DVB spheres. After carbonization and activation of the P VBC / DVB spheres, P VBC / DVB carbon sphere matrix was obtained.

2. Zwitterionic polymer brush P according to claim 1 VBC / DVB A preparation method of a carbon sphere restricted access adsorbent, characterized in that The following steps are included: The first step is carried out on P VBC / DVB The specific steps for grafting sodium 4-vinylbenzenesulfonate (Nass) and styrene (St) onto the inner surface of the carbon sphere matrix to obtain poly(St-co-Nass) are as follows: Add 1-2 g of P VBC / DVB a carbon sphere matrix, 1-2 mL of styrene (St), 1-2 g of sodium 4-vinylbenzenesulfonate (Nass), and 0.3-0.4 g of 2,2'-bipyridine (Bpy) into a 100 mL two-necked flask. Subsequently, add 30-50 mL of anisole / water, where the volume ratio of anisole / water is 9:1 (9:1, v / v). Ultrasonically treat for 5 min at a power of 100 W / L and a frequency of 40 Hz until completely dispersed, then seal the bottle mouth. Freeze for 5 min under liquid nitrogen conditions, evacuate for 3 min, and purge with nitrogen at a flow rate of 2 L / min for 5 min. After repeating the freeze-evacuate-purge nitrogen process 5 times, quickly add 0.1-0.2 g of cuprous bromide (CuBr) under a nitrogen atmosphere, and repeat the freeze-evacuate-purge nitrogen process 2 times. Polymerize at 90 °C for 6-8 h to obtain the product; The product obtained above is washed 3 times in a sintered glass funnel with 50 mL of anisole, 50 mL of 0.25 mol / L EDTANa2, 50 mL of water, and 50 mL of methanol successively, and then pumped with a vacuum pump until the product has no green color, and then dried in vacuo at 60 °C for 24 - 36 h. After the reaction, poly(St-co-Nass) is obtained. In the second step, the surface-initiated atom transfer radical polymerization (SI-ATRP) method is used to graft the functional monomer 2-methacryloyloxyethyl phosphorylcholine (MPC) onto the outer surface of the P VBC / DVB carbon sphere matrix, thereby converting the material into a block polymer with a hydrophilic outer surface, and obtaining the zwitterionic polymer brush P VBC / DVB carbon sphere restricted access adsorbent P VBC / DVB @poly(St-co-Nass)poly(MPC) are as follows: Weigh 1 - 2 g of the zwitterionic polymer brush P obtained in Step 1 VBC / DVB Carbon sphere restricted access adsorbent P VBC / DVB @poly(St-co-Nass) into a two-necked flask, add 0.4 - 0.5 g of 2,2'-bipyridine Bpy, 1 - 2 g of the monomer 2-methacryloyloxyethyl phosphorylcholine MPC, 20 - 30 mL of anisole C7H8O, ultrasonically treat for 5 min at a power of 100 W / L and a frequency of 40 Hz, freeze under liquid nitrogen conditions for 5 min, evacuate for 3 min, pass nitrogen at a flow rate of 2 L / min for 5 min, repeat 5 times, then quickly add 0.1 - 0.2 g of cuprous bromide CuBr, repeat the freeze-evacuate-pass nitrogen process 2 times, and react at 40 °C for 24 - 36 h; After the reaction is completed, it is washed 3 times successively with 50 mL of anisole C7H8O, 50 mL of 0.25 mol / L EDTANa2, 50 mL of water, and 50 mL of methanol. The product was vacuum dried at 60 °C for 24 - 36 h to obtain a product with the functional monomer 2-methacryloyloxyethyl phosphorylcholine MPC grafted on the outer surface, and an amphoteric ion polymer brush restricted access adsorbent P was obtained. VBC / DVB @poly(St-co-Nass)poly(MPC).

3. The zwitterionic polymer brush P according to claim 2 VBC / DVB A preparation method of a carbon sphere restricted access adsorbent, characterized in that P of the zwitterionic polymer brush restricted access adsorbent described VBC / DVB The preparation process of the carbon sphere matrix is operated according to the following specific steps: (1)P VBC / DVB Preparation of the ball: Weigh 1 - 2 g of polyvinyl alcohol, 0.5 - 1 g of gelatin, and 4 - 5 g of sodium chloride and dissolve them in 150 mL of deionized water. Under the condition of 80 °C, stir mechanically at 200 - 300 rpm for 1 h until completely dissolved. After obtaining a clear aqueous phase mixed solution A, it is cooled to room temperature. Weigh 15 - 20 mL of 4-vinylbenzyl chloride VBC, 10 - 15 mL of divinylbenzene DVB, 10 - 15 mL of toluene, 40 - 45 mL of dibutyl phthalate, and 0.5 - 1 g of azobisisobutyronitrile AIBN. After mixing evenly, ultrasonically dissolve it for 5 min under the conditions of a power of 100 W / L and a frequency of 40 Hz to obtain an oil phase mixed solution B. After mixing the aqueous mixed solution A and the oil-phase mixed solution B, heat at 70 °C for 8 - 12 h; after the reaction is completed, wash 3 times with 50 mL of ethanol and 50 mL of water in sequence, and after washing, dry in vacuum at 50 °C for 8 - 12 h to obtain P VBC / DVB sphere; (2)P VBC / DVB (2) Carbonization activation of the ball Put 20 - 30 g of P obtained in step (1) VBC / DVB spheres into a tubular furnace, heat them to 400 °C at a heating rate of 2.5 °C / min, and hold for 4 - 6 h; then cool them to room temperature at a rate of 2.5 °C / min to obtain carbonized P VBC / DVB carbon spheres; Put 10 - 15 g of carbonized P VBC / DVB carbon spheres into a tubular furnace, heat them to 800 °C under the protection of nitrogen with a flow rate of 100 mL / min, and the heating rate is 2.5 °C / min; adjust the nitrogen flow rate to 50 mL / min and the water vapor flow rate to 12 mL / min, and keep them at the required activation temperature for 3 - 6 h, then cool them down to room temperature at a rate of 2.5 °C / min to obtain the activated P VBC / DVB carbon spheres.

4. Zwitterionic polymer brush P according to claim 1 VBC / DVB A method for preparing a carbon sphere restricted access adsorbent, characterized in that: P of the restricted access adsorbent described VBC / DVB The carbon sphere matrix is spherical, specifically a P carbon sphere with a particle size of 400 - 800 μm VBC / DVB carbon sphere.

5. The zwitterionic polymer brush P according to any one of claims 1-4 VBC / DVB A zwitterionic polymer brush restricted access adsorbent prepared by the preparation method of the carbon sphere restricted access adsorbent.

6. The zwitterionic polymer brush P described in claim 5 VBC / DVB Application of carbon sphere restricted access adsorbent in dye detection of biological samples.

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