Preparation method and application of Zn-based super-crosslinked polymer bionic enzyme

Abstract

The invention discloses a preparation method and application of a Zn-based cross-linked polymer mimic enzyme, and the method comprises the following steps: under the protection of N2 atmosphere, adding 1H-benzotriazole and 3-aminobenzoic acid monomers into a 1, 2-dichloroethane solution, fully stirring to uniformly disperse the monomers, and initiating Friedel-Crafts alkylation reaction under the action of a catalyst anhydrous ZnCl2 to obtain the Zn-based cross-linked polymer mimic enzyme. The preparation method comprises the following steps: adding a zinc oxide solution into a reaction kettle, stirring at 45-50 DEG C for 4-5 hours to carry out pre-reaction, heating to 80-90 DEG C, reacting for 18-19 hours, and carrying out suction filtration, Soxhlet extraction and vacuum drying activation to obtain the Zn-based flexible cross-linked polymer. The Zn-based cross-linked polymer prepared by the method has an active center Zn-N site similar to natural carbonic anhydrase, rich and exposed amino and carboxyl sites on a skeleton network structure of the Zn-based cross-linked polymer can effectively recognize and capture CO2 molecules, combination of Zn and H2O molecules is weakened through hydrogen-bond interaction between monomer molecules, CO2 is promoted to be converted into HCO3 <->, and CO2 is converted into HCO3 <->. Therefore, the obvious carbonic anhydrase-like activity is shown.

Description

Technical Field

[0001] The present invention belongs to the field of biomimetic enzyme biomaterials, and particularly relates to a preparation method of a nano-catalyst Zn-based hypercrosslinked polymer biomimetic enzyme for industrial CO2 fixation. Background Art

[0002] In recent years, the accelerating global industrialization process has led to a continuous increase in CO2 emissions, further exacerbating major environmental problems such as the greenhouse effect and ocean acidification. Although renewable energy technologies are constantly developing, fossil fuels will still be the main energy source to support social development for a long time to come. Therefore, under the background of global carbon neutrality, CO2 emission reduction is still an urgent problem to be solved. The existing CO2 capture methods mainly include physical / chemical adsorption method, bioenzyme method, ion membrane separation and exchange method, and geological process fixation method. Compared with other technologies, the bioenzyme method has attracted much attention due to its advantages such as high catalytic efficiency, excellent selectivity, and mild reaction conditions.

[0003] Carbonic anhydrase II (CAII) is a biohydrolytic enzyme with Zn 2+ as the active site, which coordinates with three N atoms from different histidines (His) to form an active center, and can efficiently adsorb and convert CO2. This is attributed to its ability to rapidly and greenly catalyze the hydration of CO2 into bicarbonate and protons by coordinating with oxygen atoms in hydroxide or H2O molecules. In addition, the microenvironment (hydrophobic pocket and secondary hydrogen bond network) composed of amino acid residues around the active center controls the transfer of protons or electrons, which also has a great impact on the catalytic activity of natural CA. However, the three-dimensional structure of natural carbonic anhydrase is prone to irreversible denaturation and inactivation under non-physiological conditions such as high temperature and extreme pH, severely restricting its application and popularization in industrial scenarios.

[0004] To break through the application limitations of natural enzymes, researchers have widely developed artificial nanoenzymes that mimic the biological activity of CA to expand their biocatalytic role in non-cellular environments. In fact, these nanoenzymes that mimic CA, such as zinc-based coordination polymers, metal-organic frameworks (MOFs), and polypeptide metal complexes, not only have ideal catalytic activity but also avoid the structural sensitivity of natural CA, and have the advantages of easy synthesis and high stability.

[0005] However, most studies on CA mimics have focused on replicating the active center of natural CA, and there are still obvious deficiencies in the research on the microenvironment regulation mechanism of the mimicked CA active center. This lack of understanding of the "active center - microenvironment" synergistic effect of CA seriously hinders its practical application in engineering. Therefore, it is still an urgent task to rationally design and develop new CA mimics, understand the influence of the nano-material microenvironment on its catalytic performance and effectively control it. Summary of the Invention

[0006] In view of the deficiencies in the research on the regulation of the microenvironment of the active center of CA mimics in the current actual environment, the present invention provides a preparation method and application of a class of amino acid molecule-regulated Zn-based hypercrosslinked polymer biomimetic enzyme. Based on the pore microenvironment regulation strategy, the selective adsorption and resource utilization of CO2 are realized.

[0007] The technology of the present invention is realized through the following technical solutions:

[0008] A preparation method of a Zn-based hypercrosslinked polymer biomimetic enzyme, comprising the following steps:

[0009] (1) Swelling / dispersion of monomer molecules: Under the protection of N2 atmosphere, 1H-benzotriazole and 3-aminobenzoic acid are added to a 1,2-dichloroethane solution according to a molar ratio of 1:0.5-2, and after sufficient stirring, a mixed solution is obtained;

[0010] (2) Polymerization of monomer molecules: Under the protection of N2 atmosphere, anhydrous ZnCl2 is quickly added to the mixed solution in step (1), stirred at 45-50 °C for 4-5 h, then heated to 80-90 °C and maintained for 18-19 h to catalyze and induce the Friedel-Crafts alkylation reaction to proceed. After filtration and Soxhlet extraction, and drying, a white material is obtained, which is the Zn-based hypercrosslinked polymer biomimetic enzyme (Zn-BTA / ABA).

[0011] As a preference of the technical solution, the amount of the 1,2-dichloroethane solution in step (1) is 10-50 L of the 1,2-dichloroethane solution added to each mole of 1H-benzotriazole.

[0012] As a preference of the technical solution, in step (1), both the addition of 1H-benzotriazole and 3-aminobenzoic acid are sufficiently stirred for 5-30 min.

[0013] As a preference of the technical solution, the molar ratio of 3-aminobenzoic acid to anhydrous ZnCl2 in step (2) is 1:2-5.

[0014] As a preference of the technical solution, the Soxhlet extraction time in step (2) is 20-24 h.

[0015] As a preference of the technical solution, the stirring speed of the solution in steps (1) and (2) is 350-500 rpm.

[0016] As a preference of the technical solution, the drying time in step (2) is 10-12 h.

[0017] The Zn-based hypercrosslinked polymer biomimetic enzyme Zn-HCPs prepared by the present invention has a covalent / hydrogen bond double crosslinked network structure, and its microstructure shows a smooth rod-like structure on the surface.

[0018] The Zn-based hypercrosslinked polymer biomimetic enzyme of the present invention can be applied to the development of industrial CO2-fixing nanocatalysts.

[0019] In the present invention, 1,2-dichloroethane is used as the solvent, 3-aminobenzoic acid (3-ABA) and 1H-benzotriazole (BTA) are used as monomer molecules, and anhydrous ZnCl2 is used as the catalyst.

[0020] In the comparative experiment, indole (Id), benzimidazole (Bmz), and 1H-benzotriazole (BTA) are used as monomer molecules. By adjusting the positions and numbers of N atoms on the monomer molecules, Zn-based hypercrosslinked polymer biomimetic enzymes with different central active sites are constructed.

[0021] Based on 1H-benzotriazole, the present application uses 3-aminobenzoic acid with amino and carboxyl groups as the second monomer molecule, and polymerizes with 1H-benzotriazole monomer molecules to obtain Zn-BTA / ABA. By constructing the microenvironment around the active center, the activity of the Zn-based hypercrosslinked polymer biomimetic enzyme is enhanced.

[0022] Principle of the present invention: Aiming at the deficiency in the research on the regulation of the microenvironment of the active center of CA mimics in the actual environment, the present invention proposes a pore microenvironment regulation strategy for Zn-based hypercrosslinked polymer biomimetic enzyme Zn-HCPs by amino acid-like molecules, realizing the selective adsorption and resource utilization of CO2. Through the synergistic effect of covalent bonds and hydrogen bonds, one end of the active center of Zn-BTA / ABA is connected to three BTA molecules, and its aromatic ring skeleton forms a hydrophobic microdomain through methyl interconnection, having rich and exposed basic amino sites, which can efficiently recognize and capture acidic CO2 molecules; the other end is connected to the amino functional group of 3-ABA molecules, and a hydrogen bond network is formed through the common action of amino and carboxyl groups on the molecules, which helps to bind H2O molecules, weaken the coordination of H2O molecules with the central Zn site, and thus accelerate the deprotonation of H2O molecules and the conversion of CO2 to HCO3 - The change in this CA activity has been proven to be related to the "substrate-pore structure" interaction.

[0023] The Zn-based hypercrosslinked polymer biomimetic enzyme prepared by the present invention has a Zn-N active center and rich amino and carboxyl active sites. The construction of the hydrogen bond network between the peripheral monomer molecules realizes the microenvironment regulation of the active center of the CA mimic, achieving high-selectivity adsorption of CO2 / N2, and promoting the efficient hydration and conversion of CO2.

[0024] Compared with the prior art, the advantages of the present invention are as follows:

[0025] (1) The Zn-based hypercrosslinked polymer biomimetic enzyme prepared in the present invention is obtained by a template-free one-step method through Friedel-Crafts alkylation reaction. The preparation conditions are simple and easy to operate, and the cost is relatively low, making it suitable for large-scale industrial production.

[0026] (2) The Zn-based hypercrosslinked polymer biomimetic enzyme prepared in the present invention constructs a functional structure with different Zn-N active sites through the coordination of monomer molecules with different N sites and Zn 2+ . It exhibits the ability to catalytically convert CO2 similar to natural carbonic anhydrase. At the same time, the exposed amino and carboxyl active sites on Zn-BTA / ABA also enhance the selective adsorption of CO2, achieving efficient catalytic conversion of CO2.

[0027] (3) The present invention proposes a strategy for regulating the pore microenvironment of the Zn-based hypercrosslinked polymer biomimetic enzyme by amino acid-like molecules. By constructing a hydrophobic hydrogen bond network around the Zn-N active center, the coordination between H2O molecules and the central Zn site is weakened, thereby accelerating the deprotonation of H2O molecules and the conversion of CO2 to HCO3 - . The mass of CaCO3 catalytically converted from CO2 hydration per unit time is as high as 31.4 mg, which is much higher than that of the Zn-HCPs biomimetic enzyme material with only Zn-N active centers.

[0028] (4) By in-situ constructing the central active site and the peripheral hydrogen bond network of the biomimetic carbonic anhydrase on Zn-HCPs, the present invention proves that the peripheral hydrogen bond network structure of the biomimetic carbonic anhydrase active center also has a significant impact on its catalytic activity, which can significantly enhance the enzyme-like catalytic activity of the biomimetic enzyme material. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 SEM images of Zn-Id, Zn-Bmz, and Zn-BTA prepared in Comparative Examples 1-3 and Zn-BTA / ABA prepared in Example 1.

[0030] Figure 2 PXRD patterns of Zn-Id, Zn-Bmz, and Zn-BTA prepared in Comparative Examples 1-3 and Zn-BTA / ABA prepared in Example 1.

[0031] Figure 3 FT-IR spectra of Zn-Id, Zn-Bmz, and Zn-BTA prepared in Comparative Examples 1-3 and Zn-BTA / ABA prepared in Example 1.

[0032] Figure 4 CO2 adsorption isotherms of Zn-Id, Zn-Bmz, and Zn-BTA prepared in Comparative Examples 1-3 and Zn-BTA / ABA prepared in Example 1 at 298 K.

[0033] Figure 5 a shows the CO2 and N2 adsorption isotherms of Zn-BTA / ABA prepared in Example 1 and the corresponding DSLF and SSLF fittings; Figure 5 b is a schematic diagram of the IAST selectivity of Zn-BTA / ABA for CO2 / N2 at 298K.

[0034] Figure 6 a is the UV full-wavelength scanning spectrum of Zn-BTA / ABA prepared in Example 1 for p-NP with different concentrations in HEPES buffer (pH = 8.0, 50 mM); Figure 6 b is the standard curve of Zn-BTA / ABA for known concentrations of p-NP.

[0035] Figure 7 a is the time-dependent absorbance change of different Zn-HCPs at UV = 402 nm; Figure 7 b is the kinetic curve of different Zn-HCPs for catalytic conversion of CO2 to HCO3 - in HEPES buffer (50 mM).

[0036] Figure 8 is the change trend of the pH value of HEPES buffer with the continuous introduction of CO2 under the action of different Zn-HCPs.

[0037] Figure 9 is a comparison chart of the performance differences of different Zn-HCPs in fixing and converting CO2 into CaCO3.

[0038] Figure 10 is a comparison chart of the catalytic performance between Zn-BTA / ABA prepared in Example 1 and the reported CA mimetics. Detailed implementation mode

[0039] The following further describes the present invention in conjunction with the drawings and embodiments, but the scope of protection required by the present invention is not limited to the scope protected by the embodiments. Some non-essential improvements and adjustments made by those skilled in the art based on the above content of the present invention all fall within the protection scope of the present invention. The specific process parameters and the like in the following examples are also only an example within a suitable range, that is, those skilled in the art can make selections within a suitable range through the description in this article, rather than being limited to the specific values in the following examples.

[0040] Example 1

[0041] A preparation method of an isostructural Zn-based cross-linked polymer biomimetic enzyme Zn-BTA / ABA, comprising the following steps:

[0042] (1) Swelling of monomer molecules: Under the protection of N2 atmosphere, first add 50 mL of dichloroethane solution into a 250 mL three-necked flask, then add 5 mmol of monomer BTA and 5 mmol of monomer 3-ABA into it. After stirring thoroughly for 5 - 10 min under magnetic stirring at 400 rpm, make it evenly mixed to obtain a mixed solution;

[0043] (2) Polymerization of monomer molecules: Under the protection of N2 atmosphere, add 20 mmol of catalyst anhydrous ZnCl2 into the mixed solution of step (1), place it in a water bath at 45 °C and stir magnetically for 5 h (rotation speed 400 rpm), then raise the temperature to 80 °C and keep it for 19 h; After reacting for 24 h, stop heating, add 30 mL of methanol solution into the three-necked flask to quench the reaction. The obtained solution is filtered by suction and extracted by Soxhlet for 24 h to remove impurities. After drying at 70 °C at room temperature and vacuum drying at 80 °C for 12 h, the obtained white product is the Zn-based hypercrosslinked polymer biomimetic enzyme Zn-BTA / ABA (denoted as: Zn-BTA / ABA).

[0044] Comparative Example 1

[0045] A preparation method of a polymer biomimetic enzyme Zn-Id, comprising the following steps:

[0046] (1) Swelling of monomer molecules: Under the protection of N2 atmosphere, first add 50 mL of dichloroethane (DCE) solution into a 250 mL three-necked flask, then add 10 mmol of monomer indole (Id), and stir thoroughly for 5 - 10 min under magnetic stirring at 400 rpm to make it evenly mixed;

[0047] (2) Polymerization of monomer molecules: Under the protection of N2 atmosphere, add 20 mmol of catalyst anhydrous ZnCl2 into the solution of step (1), place it in a water bath at 45 °C and stir magnetically for 5 h (rotation speed 400 rpm), then raise the temperature to 80 °C and keep it for 19 h; After reacting for 24 h, stop heating, add 30 mL of methanol solution into the three-necked flask to quench the reaction. The obtained solution is filtered by suction and extracted by Soxhlet for 24 h to remove impurities. After drying at 70 °C at room temperature and vacuum drying at 80 °C for 12 h, finally a white product is obtained, which is the polymer biomimetic enzyme Zn-Id (denoted as: Zn-Id).

[0048] Comparative Example 2

[0049] A preparation method of a polymer biomimetic enzyme Zn-Bmz, comprising the following steps:

[0050] (1) Swelling of monomer molecules: Under the protection of N2 atmosphere, first add 50 mL of dichloroethane solution into a 250 mL three-necked flask, then add 10 mmol of monomer benzimidazole Bmz, and stir well for 5 - 10 min at 400 rpm of magnetic stirring to make it evenly mixed;

[0051] (2) Polymerization of monomer molecules: Under the protection of N2 atmosphere, add 20 mmol of catalyst anhydrous ZnCl2 into the solution of step (1), place it in a water bath at 45 °C and stir magnetically for 5 h (rotation speed 400 rpm), then raise the temperature to 80 °C and keep it for 19 h; after reacting for 24 h, stop heating, add 30 mL of methanol solution into the three-necked flask to quench the reaction, the obtained solution is filtered by suction and extracted by Soxhlet for 24 h to remove impurities, and then dried at 70 °C at room temperature and vacuum-dried at 80 °C for 12 h, and finally a white product is obtained, which is the polymer biomimetic enzyme Zn-Bmz (denoted as: Zn-Bmz).

[0052] Comparative Example 3

[0053] A preparation method of a polymer biomimetic enzyme Zn-BTA includes the following steps:

[0054] (1) Swelling of monomer molecules: Under the protection of N2 atmosphere, first add 50 mL of dichloroethane solution into a 250 mL three-necked flask, then add 10 mmol of monomer BTA, and stir well for 5 - 10 min at 400 rpm of magnetic stirring to make it evenly mixed;

[0055] (2) Polymerization of monomer molecules: Under the protection of N2 atmosphere, add 20 mmol of catalyst anhydrous ZnCl2 into the solution of step (1), place it in a water bath at 45 °C and stir magnetically for 5 h (rotation speed 400 rpm), then raise the temperature to 80 °C and keep it for 19 h; after reacting for 24 h, stop heating, add 30 mL of methanol solution into the three-necked flask to quench the reaction, the obtained solution is filtered by suction and extracted by Soxhlet for 24 h to remove impurities, and then dried at 70 °C at room temperature and vacuum-dried at 80 °C for 12 h, and finally a white product is obtained, which is the polymer biomimetic enzyme Zn-BTA (denoted as: Zn-BTA).

[0056] Material property testing

[0057] Carry out structural and property characterization and analysis on the products prepared in Example 1 of the present invention and Comparative Examples 1 - 3.

[0058] (I) Microstructural characterization

[0059] Use a Hitachi SU8020 scanning electron microscope (SEM) in Japan to carry out microstructural characterization on Zn-BTA / ABA prepared in Example 1 of the present invention and Zn-Id, Zn-Bmz and Zn-BTA prepared in Comparative Examples 1 - 3, asFigure 1 as shown

[0060] Figure 1 a-d are SEM images of Zn-BTA / ABA of Example 1 and Zn-Id, Zn-Bmz, and Zn-BTA prepared in Comparative Examples 1-3, respectively. It can be clearly seen that Zn-Id shows a spherical particle accumulation with a size of about 100 nm.( Figure 1 a). Different from Zn-Id, Zn-Bmz and Zn-BTA have obvious short rod-like structures, while Zn-Bmz has a wide rod-like structure with smooth edges and corners, and its length and width are about 1.0 and 0.2 μm, respectively( Figure 1 b,c). The structural differences among these three Zn-HCPs are attributed to the differences in the cross-linked networks constructed by the active center Zn-N coordination, which are affected by the number of N atoms on the monomer molecules. Further, Zn-BTA / ABA shows a more slender and smooth rod-like structure with a length of about 1.0-2.0 μm( Figure 1 d). This indicates that the implantation of 3-ABA molecules with amino and carboxyl groups in Zn-BTA / ABA constructs a polymer backbone hydrogen bond network, preventing the monomer molecules from diffusing into the interior of Zn-BTA / ABA with the DCE solution and forming a slender and smooth rod-like structure.

[0061] (II) Crystal Structure Characterization

[0062] The crystal structures of Zn-BTA / ABA prepared in Example 1 of the present invention and Zn-Id, Zn-Bmz, and Zn-BTA prepared in Comparative Examples 1-3 were characterized by using a Japanese RIGAKU SMARTLAB3KW type powder X-ray diffractometer (PXRD) with CuKα radiation in the range of 2θ = 5-60° as shown Figure 2 as follows

[0063] It can be seen from Figure 2 that Zn-Id and Zn-Bmz only show characteristic amorphous graphite carbon peaks (black marks), which belong to the (101) crystal plane of hexagonal graphite, indicating their amorphous nature with a certain degree of graphitization. For Zn-BTA and Zn-BTA / ABA, these two materials show crystallization characteristic peaks at 2θ = 10.79°, 17.75°, 20.84°, and 32.96°, which belong to the (111), (220), (311), and (511) crystal planes of graphitized carbon, respectively. In addition, a Zn-N characteristic peak located at 2θ = 21.83° belonging to the (110) crystal plane also appears in these two materials, proving the existence of Zn-N coordination in the materials.

[0064] (III) Functional Group Structure Characterization

[0065] The functional group structures of Zn-BTA / ABA prepared in Example 1 and Zn-Id, Zn-Bmz, and Zn-BTA prepared in Comparative Examples 1-3 were characterized using an IRTracer-100 Fourier transform infrared spectrometer (FT-IR) (scanning range: 500-2500 cm -1 ), and the results are as Figure 3 shown. It can be seen that all samples exhibited C═C stretching vibrations (1690 and 1610 cm -1 ) and C-H deformation / bending vibrations (1500 and 1210 cm -1 ), which belong to the aromatic backbone of the polymer, indicating that these materials all have a typical hypercrosslinked polymer structure. In addition, all Zn-HCPs showed N-H deformation vibrations (773, 750 cm -1 ), which are attributed to the amine group and are typical structural features of imidazole and triazole groups. Among them, Zn-Bmz also exhibited C═N vibrations (613 cm -1 ), while Zn-BTA exhibited N═N stretching vibrations (613 cm -1 ).

[0066] (IV) Characterization and analysis of CO2 adsorption isotherms and CO2 / N2 selective adsorption performance of different polymers

[0067] The CO2 adsorption isotherms of Zn-Id, Zn-Bmz, and Zn-BTA prepared in Comparative Examples 1-3 were measured using a Micromertics 3Flex surface characterization analyzer in the United States, and the CO2 and N2 adsorption isotherms of Zn-BTA / ABA prepared in Example 1 of the present invention were measured, as Figures 4 - 5 shown.

[0068] At Figure 4Figure 0 shows the CO2 adsorption isotherms of the above Zn-HCPs at 298 K, with typical type I / II characteristics. Due to the strong interaction between CO2 molecules and the sample surface, the adsorption of CO2 on the sample increases rapidly at relatively low pressures (P < 0.1 bar). As the relative pressure increases, the amount of CO2 adsorbed by the sample gradually increases over the entire measured pressure range and bends towards the pressure axis until adsorption saturation is reached at a pressure of 1.04 bar. Among them, the order of the saturated adsorption amounts of CO2 by the four different materials is: Zn-BTA / ABA (0.68 mmol / g) > Zn-BTA (0.53 mmol / g) > Zn-Bmz (0.35 mmol / g) > Zn-Id (0.25 mmol / g). It is worth noting that Zn-BTA / ABA exhibits the highest saturated adsorption capacity for CO2. This is attributed to the enhanced dipole-quadrupole interaction with CO2 molecules by the exposed amino and carboxyl active sites in Zn-BTA / ABA, which improves the adsorption force; at the same time, multilayer adsorption (mesoporous filling) of CO2 molecules is achieved through the presence of hydrogen bond networks in its framework structure, thereby realizing high-capacity capture of CO2.

[0069] Figure 5 Figure a shows the experimental data of the CO2 and N2 adsorption isotherms of Zn-BTA / ABA and the corresponding fittings of the two-site DSLF and single-site SSLF. It can be seen that the DSLF and SSLF equations fit the experimental data well (R 2 > 0.999). In addition, Figure 5 Figure b shows the selectivity of Zn-BTA / ABA for CO2 in 10 / 90 and 15 / 85 CO2 / N2 gas mixtures. It can be seen that the CO2 / N2 selectivity of Zn-BTA / ABA increases with the increase of the total pressure and the partial pressure of CO2, which is because its adsorption affinity for CO2 increases with the increase of pressure, while the change in the adsorption of N2 can be ignored. For the typical composition of flue gas emissions after coal combustion (P CO2 / P N2 = 0.15 / 0.85), at 298 K and 1.0 bar, the adsorption selectivity of Zn-BTA / ABA for CO2 / N2 is as high as 1427, showing ultra-high CO2 selectivity and enabling better selective adsorption and conversion of CO2 in actual industrial scenarios.

[0070] (V) Analysis of enzyme-like activity

[0071] The Zn-BTA / ABA prepared in Example 1 of the present invention was analyzed for carbonic anhydrase-like activity using a UV-Vis spectrophotometer (PERSEE Tu-1901 250 - 800 nm) at 298 K, as Figure 6As shown, p-NPA was selected as the model substrate for hydrolysis to systematically evaluate the CA-mimicking activity of Zn-BTA / ABA. Since the mechanisms between CO2 hydration and p-NPA hydrolysis are similar, the change in the concentration of the hydrolysis product p-NP can be monitored by colorimetric analysis of the sample at UV = 402 nm.

[0072] As Figure 6 shown in a, in order to quantitatively determine the concentration of the generated p-NP to evaluate the enzyme-like activity of the samples, a calibration curve of standard p-NP with different known concentrations (0 - 150 μM) was established. The absorbance of the HEPES buffer (pH = 8.0, 50 mM) containing p-NP at UV = 402 nm gradually increased with the increase in the p-NP concentration. Figure 6 The results in b showed a positive correlation between the p-NP concentration and the absorbance of the solution. This result indicates that as the p-NP concentration in the solution increases, the measured absorbance value of the solution is higher.

[0073] (VI) Analysis of enzyme-like catalytic kinetic performance

[0074] Figure 7 a shows the kinetic curves of the hydrolysis of p-NPA catalyzed by different Zn-HCPs and control samples recorded within 30 min. The self-decomposition of p-NPA without any catalyst was set as the blank control. Under the catalysis of different Zn-HCPs and control samples, the absorbance of the reaction solution at UV = 402 nm increased linearly to varying degrees with time. Compared with the blank control, the hydrolysis ability of free Zn 2+ towards p-NPA was negligible. Different HCPs coordinated with monomer molecules to form a distorted tetrahedral skeleton similar to natural CA, which had a catalytic effect on the hydrolysis of p-NPA. It can be seen that the ability of Zn-Id, Zn-Bmz, and Zn-BTA to catalyze the hydrolysis of p-NPA gradually increased, which was attributed to the formation of more Zn-N catalytic sites in the materials. Compared with Zn-BTA, Zn-BTA / ABA had a stronger ability to catalyze the hydrolysis of p-NPA, and its catalytic rate (k = 4.97 μM / min) was 1.6 - 7.4 times that of other tested samples. This was because after the insertion of 3-ABA molecules, their amino functional groups were connected to the other end of the active center of Zn-BTA / ABA, and a peripheral hydrogen bond network was formed through the combined action of the amino and carboxyl groups on the molecule, which helped to bind H2O molecules, weakened the coordination of H2O molecules with the central Zn site, and thus accelerated the deprotonation of H2O molecules and the conversion of CO2 to HCO3 - .

[0075] Figure 7 b shows the conversion of CO2 to HCO3 catalyzed by different Zn-HCPs in HEPES buffer (50 mM) -The kinetic curves were fitted by the pseudo-second-order kinetic model. This model showed good fitting with the experimental data (R 2 > 0.99), and the fitting parameters were calculated through equations. According to the experimental results, neither Zn 2+ nor monomer molecules (Id, Bmz, and BTA) alone could promote the hydrolysis of p-NPA, indicating that the Zn 2+ -N coordination structure and the peripheral hydrogen bond network formed between Zn and the series of monomer molecules largely determined their ability to catalyze the hydrolysis of p-NPA. Compared with other materials, Zn-BTA / ABA exhibited the highest hydrolysis kinetic rate (k c = 0.18 min -1 ⁻¹), which was 2.6 - 7.8 times that of other samples, indicating its strongest ability to catalyze the hydrolysis of CO2 to HCO3 - .

[0076] Figure 8 shows the pH decay of HEPES buffer (50 mM) upon continuous introduction of CO2 in the presence of different Zn-HCPs. It can be seen that under the catalysis of Zn-BTA / ABA, the pH value of the buffer solution rapidly decreased from 7.0 to 6.3 within 15 min. Around 25 min, the CO2 hydrolysis process catalyzed by Zn-BTA / ABA reached equilibrium, much faster than other samples, indicating that the presence of Zn-BTA / ABA significantly accelerated the hydrolysis of CO2.

[0077] (VII) Analysis of the process of polymer continuously catalyzing CO2 conversion to CaCO3

[0078] To verify the feasibility of Zn-HCPs for CO2 sequestration, an excess of CaCl2 was added to the HEPES buffer to precipitate carbonate (Ca 2+ ²⁺ + CO3 2- ²⁻ → CaCO3↓). Figure 9 shows the mass of CaCO3 generated by the blank sample, free Zn 2+ and different Zn-HCPs catalyzing CO2 conversion after 1 hour of reaction, which were 6.6 - 31.4 mg respectively. Among them, the mass of CaCO3 generated by Zn-BTA / ABA catalyzing CO2 conversion was 31.4 mg, much higher than the other three materials Zn-Id (8.9 mg), Zn-Bmz (14.2 mg), and Zn-BTA (22.8 mg). The mass of CaCO3 generated by Zn-BTA / ABA catalyzing CO2 conversion was 4.8 times that of the blank control (without catalyst). In addition, the PXRD patterns of the CaCO3 obtained from these reactions were consistent with those of commercially available CaCO3, demonstrating that Zn-BTA / ABA successfully fixed and converted CO2 into CaCO3.

[0079] (8) Comparison of the catalytic performance of the product of the present invention with other biomimetic enzyme materials

[0080] By comparing the catalytic performance of Zn-BTA / ABA synthesized in Example 1 of the present invention with that of other reported biomimetic CA materials in the literature, the results are shown in Table 2 and Figure 10 as follows.

[0081] Table 2 Comparison of the catalytic performance of Zn-BTA / ABA and other CA mimics at 298K

[0082]

[0083] Note: 1 is the initial degradation rate value of p-NPA to compare the catalytic performance of Zn-BTA / ABA with other reported CA mimics.

[0084] 2 is the mass of CaCO3 obtained by fixing CO2 per milligram of catalyst per hour.

[0085] 3 is the ratio of the mass of CaCO3 obtained by fixing CO2 with the catalyst to the mass of CaCO3 obtained with a blank sample (without catalyst).

[0086] 4 is the experimental conditions, including pH value, reaction temperature and catalyst concentration, where the reaction temperature is 298K.

[0087] As shown in Table 2, under similar reaction conditions, the mass of CO2 converted to CaCO3 by Zn-BTA / ABA per unit time is 10.5 mg / mg·h, which is 1.1 - 1.7 times that of other reported CA mimic catalysts. Figure 10 The relationship between the initial degradation rate value of p-NPA and the mass-time of CO2 conversion to CaCO3 of different materials is shown, indicating that the catalytic performance of Zn-BTA / ABA is much higher than that of the reported CA mimics, and it is a biomimetic enzyme material with excellent prospects in the field of CO2 resource utilization.

[0088] The examples given in the present invention are not intended to limit the embodiments of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to enumerate all the embodiments here. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included in the protection scope of the claims of the present invention.

Claims

1. A preparation method of a Zn-based hypercrosslinked polymer biomimetic enzyme, characterized in that, It includes the following steps: (1) Swelling / dispersion of monomer molecules: Under the protection of N2 atmosphere, 1H-benzotriazole and 3-aminobenzoic acid are added to a 1,2-dichloroethane solution according to a molar ratio of 1:0.5-2, and a mixed solution is obtained after sufficient stirring; (2) Polymerization of monomer molecules: Under the protection of N2 atmosphere, anhydrous ZnCl2 is quickly added to the mixed solution in step (1), stirred at 45-50 °C for 4-5 h, then heated to 80-90 °C and maintained for 18-19 h to catalyze and induce the Friedel-Crafts alkylation reaction to proceed. After filtration and Soxhlet extraction, a white material is obtained after drying, which is the Zn-based hypercrosslinked polymer biomimetic enzyme.

2. The preparation method of the Zn-based hypercrosslinked polymer biomimetic enzyme according to claim 1, wherein: In step (1), the amount of 1,2-dichloroethane solution used is 10-50 L of 1,2-dichloroethane solution added per mole of 1H-benzotriazole.

3. The preparation method of the Zn-based hypercrosslinked polymer biomimetic enzyme according to claim 1, wherein: In step (1), both the addition of 1H-benzotriazole and 3-aminobenzoic acid are sufficiently stirred for 5-30 min.

4. The preparation method of the Zn-based hypercrosslinked polymer biomimetic enzyme according to claim 1, wherein: In step (2), the molar ratio of 3-aminobenzoic acid to anhydrous ZnCl2 is 1:2-5.

5. The preparation method of the Zn-based hypercrosslinked polymer biomimetic enzyme according to claim 1, characterized in that: In step (2), the Soxhlet extraction time is 20-24 h.

6. The preparation method of the Zn-based hypercrosslinked polymer biomimetic enzyme according to claim 1, characterized in that: In step (2), the drying time is 10-12 h.

7. The preparation method of the Zn-based hypercrosslinked polymer biomimetic enzyme according to claim 1, characterized in that: In steps (1) and (2), the stirring speed of the solution is 350-500 rpm.

8. Application of the Zn-based hypercrosslinked polymer biomimetic enzyme prepared by the method according to any one of claims 1 to 7, characterized in that: Application of Zn-based hypercrosslinked polymer biomimetic enzyme in the development of industrial CO2 fixation nanocatalysts by simulating the active center and microenvironment of carbonic anhydrase.

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