A method for removing cyclic chlorine disinfection byproducts based on polyacrylic acid-coated N-doped MOFs-derived carbon adsorbent

Abstract

The present invention relates to the technical field of adsorption of substituted benzene poisons, and discloses a novel cyclic chlorine disinfection by-product removal method based on a polyacrylic acid-coated N-doped MOFs-derived carbon adsorbent. The MOFs-derived carbon material is a polyacrylic acid-coated N-doped MOFs-derived carbon material, and the adsorption rate of substituted benzene substances is as high as more than 90%. The N-doped MOFs-derived carbon is obtained by high-temperature calcination of ZIF-8. High-temperature carbonization is used to cause the organic skeleton in the precursor MOF to collapse and the metal center to gasify, ultimately producing a hierarchical pore structure and a high pore volume. The micropores provide adsorption sites for the target, and the mesopores can effectively enhance the mass transfer of the target in the material. The addition of N atoms can flexibly adjust the pore size, affect the dielectric properties of the MOFs-derived carbon, and provide more adsorption sites, thereby improving the adsorption capacity of the target, and the adsorption rate for substituted benzene substances is as high as more than 90%.

Description

Technical Field

[0001] The present invention relates to the technical field of substituted benzene poison adsorption, and in particular to a method for removing cyclic chlorine disinfection byproducts based on a polyacrylic acid-coated N-doped MOFs-derived carbon adsorbent. Background Art

[0002] The widespread use of substituted benzenes, especially cyclic chlorinated compounds, as disinfectants and their incorporation into daily life has drawn considerable attention to their potential carcinogenic and teratogenic toxicity. Residual substituted benzenes in drinking water, rivers, and lakes pose significant environmental risks and a range of problems for humans and aquatic life. Currently, the main methods for treating substituted benzene disinfectant byproducts in the environment include adsorption removal, chemical oxidation, photocatalytic degradation, biodegradation, and hybrid treatment technologies. Adsorption removal technology, due to its environmental friendliness, low cost, and ease of operation, has gained widespread adoption.

[0003] Chinese patent application No. 201911262353.8 discloses a preparation method and application of a metal organic framework-derived magnetic porous carbon material, a MOFs-derived magnetic porous carbon material and its extraction method for dyes (amaranth and carmine), using MIL-101 (Fe) as raw material and KOH as activator, MOFs-derived magnetic porous carbon material (MPCK) was prepared by high-temperature calcination under N2 protection, and had significant adsorption effect on amaranth and carmine; however, whether the application scope of this method can be expanded to the adsorption of other substituted benzene substances, especially cyclic chlorine, and whether the adsorption effect can meet the national standards is still uncertain. Summary of the Invention

[0004] In view of the lack of effective adsorbents for the by-products and residues of current substituted benzene disinfectants in the prior art, the present invention provides a MOFs-derived carbon material with high adsorption capacity for substituted benzene substances, and the adsorption rate of substituted benzene disinfectants is as high as over 90%; the present invention also provides a method for preparing the MOFs-derived carbon material with high adsorption capacity for substituted benzene substances, and the prepared MOFs-derived carbon material has an adsorption rate of over 90% for substituted benzene disinfectants; the present invention also provides an application of the MOFs-derived carbon material with high adsorption capacity for substituted benzene substances for adsorbing substituted benzene substances, and when used for adsorbing substituted benzene substances, the adsorption rate is as high as over 90%.

[0005] The present invention is achieved by the following technical solutions:

[0006] The invention discloses a MOFs-derived carbon material with high adsorption capacity for substituted benzene substances. The MOFs-derived carbon material is a polyacrylic acid-coated N-doped MOFs-derived carbon material, and the adsorption rate for substituted benzene substances is as high as over 90%.

[0007] Preferably, the N-doped MOFs-derived carbon is obtained by calcining ZIF-8 at high temperature.

[0008] A method for preparing a MOFs-derived carbon material having high adsorption capacity for substituted benzene substances comprises the following steps:

[0009] 1) Preparation of ZIF-8: Pour a methanol solution of dimethylimidazole into a methanol solution of hydrated zinc nitrate at room temperature, stir and allow to stand, separate the solid and liquid, wash and dry the solid to obtain ZIF-8, wherein the molar ratio of hydrated zinc nitrate to dimethylimidazole is 1:6-10;

[0010] 2) preparing N-doped MOFs-derived carbon: calcining the ZIF-8 prepared in step 1) at 600-1000° C. for several hours under inert gas protection to obtain the N-doped MOFs-derived carbon; 3) preparing polyacrylic acid-coated N-doped MOFs-derived carbon: adding the N-doped MOFs-derived carbon prepared in step 2) to a polyacrylic acid aqueous solution, mixing the N-doped MOFs-derived carbon with polyacrylic acid in a mass ratio of 1:8-12 for reaction, collecting the precipitate by solid-liquid separation, and washing and drying to obtain the polyacrylic acid-coated N-doped MOFs-derived carbon.

[0011] Preferably, in step 1), the stirring time is 2.5 to 4 hours, the standing time is 10 to 14 hours, the drying temperature is 55 to 65° C., and the drying time is 10 to 14 hours.

[0012] Preferably, in step 2), the temperature is raised to 600-1000° C. by a three-stage gradient heating method, the calcination time is 1.5-3 hours, and the inert gas is nitrogen or argon.

[0013] Preferably, the average molecular weight of the polyacrylic acid in step 3) is 3,000 to 10,000, and the concentration of the polyacrylic acid aqueous solution is 50 wt%.

[0014] A method for removing substituted benzene poisons from liquids using a MOFs-derived carbon material having high adsorption capacity for substituted benzenes or a MOFs-derived carbon material prepared using the method for preparing the MOFs-derived carbon material having high adsorption capacity for substituted benzenes, wherein the dosage of the polyacrylic acid-coated N-doped MOFs-derived carbon is 0.4 mg / mL; and / or the concentration of pollutants in water is greater than 20 ng / mL; and / or the applicable pH range is 3 to 9; and / or the applicable temperature is less than 50°C.

[0015] Preferably, the method further comprises using chromatography-mass spectrometry to detect the amount of substituted benzene poisons adsorbed by the MOFs-derived carbon material.

[0016] Preferably, the chromatography-mass spectrometry detection conditions are:

[0017] Chromatographic separation was performed on an Exion LC AC system using a Phenomenex Kinetex Biphenyl (50 × 3.0 mm, 2.6 μm) column;

[0018] Mobile phase A was 5 mM ammonium formate in water, mobile phase B was methanol, and the gradient elution program was as follows: 0-0.5 min, 5% B; 0.5-2 min, 5%-95% B; 2-5 min, 95% B; 5-5.1 min, 95%-5% B; 5.1-7 min, 5% B; the flow rate was 0.4 mL / min, the injection volume was 5 μL, and the column temperature was 40°C.

[0019] The ion source was atmospheric pressure chemical ionization (APCI) source; the ionization mode was negative ion mode; the ion source temperature was 250°C; the nebulizing gas pressure was 60 psi, the curtain gas pressure was 25 psi, the collision gas pressure was 8 psi, and the mass spectrometry scanning mode was multiple reaction monitoring mode.

[0020] Beneficial effects of the present invention:

[0021] (1) It fills the gap in the current technology for efficient adsorbents for substituted benzene substances. High-temperature carbonization is used to collapse the organic skeleton in the precursor MOF and gasify the metal center, ultimately producing a hierarchical pore structure and high pore volume. The micropores provide adsorption sites for the target substance, and the mesopores can effectively enhance the mass transfer of the target substance within the material. The addition of nitrogen atoms can flexibly adjust the pore size, affect the dielectric properties of MOFs-derived carbon, and provide more adsorption sites, thereby improving the adsorption capacity of the target substance. The adsorption rate for substituted benzene substances is as high as over 90%.

[0022] (2) Polyacrylic acid, as a non-toxic, water-soluble commercial dispersant, makes the surface of N-doped MOFs-derived carbon carry a large amount of negative charge, which makes the material almost non-interactive with the reaction container and has excellent dispersion properties in the application system, which significantly increases the adsorption area and improves the adsorption rate.

[0023] (3) Polyacrylic acid-coated N-doped derivative carbon materials have good stability and can undergo multiple adsorption-regeneration cycles continuously. Since the adsorption of the target substance to the material is driven only by non-covalent bonds such as hydrogen bonds, halogen bonds, π-π interactions, electrostatic interactions, and hydrophobic interactions, the target substance is easily eluted, and the regeneration cost is low. In addition, the material itself is minimally damaged during the regeneration process.

[0024] (4) Environmentally friendly, the metal center of ZIF-8 is Zn 2+ After carbonization at a temperature above 900℃, Zn 2+Gasification occurs, avoiding the risk of metal ion leaching in practical applications. Therefore, both polyacrylic acid and N-doped MOFs-derived carbon are not easily migrated and transformed in an aqueous environment, and the material itself does not introduce any toxic substances.

[0025] (5) The preparation process is simple and low-cost, which is conducive to large-scale industrial promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 These are scanning electron micrographs of the ZIF-8 obtained in Example 1 and the N-doped MOFs-derived carbons obtained at different carbonization temperatures.

[0027] Figure 2 The comparison of the removal rates of chlorophenol by ZIF-8 obtained in Example 3 and N-doped MOFs-derived carbon obtained at different carbonization temperatures is shown.

[0028] Figure 3 This is a scanning electron microscope image of the polyacrylic acid-coated N-doped MOFs-derived carbon obtained in Example 2.

[0029] Figure 4 The comparison of the removal rates of chlorophenols by ZIF-8 obtained in Example 4, the derived carbon obtained by carbonization at 1000°C, and the N-doped MOFs derived carbon coated with polyacrylic acid.

[0030] Figure 5 This is a comparison of the adsorption capacity of chlorophenol after four cycles of adsorption by the polyacrylic acid-coated N-doped MOFs-derived carbon obtained in Example 4.

[0031] Figure 6 The N-doped MOFs-derived carbon coated with polyacrylic acid adsorbs chlorophenols at different pH, salt ion concentrations, and humic acid concentrations.

[0032] Figure 7 The application performance of N-doped MOFs-derived carbon coated with polyacrylic acid in the adsorption of chlorophenols in actual water samples.

[0033] Figure 8 This is a graph showing the Zeta potential changes of N-doped MOFs-derived carbon coated with polyacrylic acid under different pH conditions.

[0034] Figure 9 This is a comparison diagram of the Zeta potential of N-doped MOFs-derived carbon, polyacrylic acid, and polyacrylic acid-coated N-doped MOFs-derived carbon.

[0035] Figure 10 XRD comparison diagrams of ZIF-8, N-doped MOFs-derived carbon and polyacrylic acid-coated N-doped MOFs-derived carbon.

[0036] Figure 11XRD comparison diagram of N-doped MOFs-derived carbon coated with polyacrylic acid and N-doped MOFs-derived carbon coated with polyacrylic acid after being placed in water for 15 days.

[0037] Figure 12 This is the XRD comparison diagram of N-doped MOFs-derived carbon coated with polyacrylic acid and N-doped MOFs-derived carbon coated with polyacrylic acid after 4 cycles of use.

[0038] Figure 13 Fitting curves, pseudo-first-order kinetic model (c) and pseudo-second-order kinetic model (d) of DBPs removal rate (a) and adsorption capacity (b) of polyacrylic acid-coated N-doped MOFs-derived carbon versus time.

[0039] Figure 14 Comparison of the adsorption isotherms of (a) 2,4-DCP and (b) 2,4,6-TCP on N-doped MOFs-derived carbon coated with polyacrylic acid.

[0040] Figure 15 The XPS comparison spectra of N-doped MOFs-derived carbon coated with polyacrylic acid and N-doped MOFs-derived carbon.

[0041] Figure 16 The XPS comparison spectra of N-doped MOFs-derived carbon coated with polyacrylic acid before and after adsorption. DETAILED DESCRIPTION

[0042] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention; in the embodiments, unless otherwise specified, the means used are conventional means in the art; the terms "comprising", "including" or any other variations thereof used herein are intended to cover non-exclusive inclusions; for example, a composition, step, method, product or apparatus comprising the listed elements is not necessarily limited to those elements, but may include other elements not explicitly listed or elements inherent to such a composition, step, method, product or apparatus; in addition, the technical features involved in the various embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other; the experimental raw materials used in the embodiments of the present invention and the comparative examples are all commercially available products.

[0043] Example 1

[0044] A method for preparing an N-doped MOFs-derived carbon material for removing substituted benzene disinfection byproducts in water comprises the following steps:

[0045] S1. Dissolve zinc nitrate hexahydrate in methanol to obtain Solution I. Dissolve dimethylimidazole in methanol to obtain Solution II. Slowly pour Solution II into Solution I under magnetic stirring. Stir magnetically at room temperature for 3 hours and allow to settle for 12 hours. The mass ratio of zinc nitrate hexahydrate to dimethylimidazole is 1:8.

[0046] S2. Remove part of the supernatant from the system after precipitation of S1, and wash the remaining white precipitate with methanol three times, centrifuge, filter, and dry at 60°C for 12 hours to obtain solid I.

[0047] S3. Grind the solid I in S2 and transfer it to an alumina crucible, place it in a tube furnace, and under the protection of a nitrogen atmosphere, use a three-stage gradient heating method at a heating rate of 5°C / min to the preset temperature, calcine for 2 hours, cool and grind to obtain solid II.

[0048] The preset temperatures described in S3 are 600, 700, 800, 900, and 1000°C.

[0049] Example 2

[0050] A method for preparing a polyacrylic acid-coated N-doped MOFs-derived carbon material for removing substituted benzene disinfection byproducts in water comprises the following steps:

[0051] S1. Dissolve zinc nitrate hexahydrate in methanol to obtain solution I, dissolve dimethylimidazole in methanol to obtain solution II, slowly pour solution II into solution I under magnetic stirring, magnetically stir at room temperature for 3 hours, and let it stand for 12 hours. The mass ratio of zinc nitrate hexahydrate to dimethylimidazole is 1:8.

[0052] S2. Remove part of the supernatant from the system after precipitation of S1, and wash the remaining white precipitate with methanol three times, centrifuge, filter, and dry at 60°C for 12 hours to obtain solid I.

[0053] S3. Grind the solid I in S2 and transfer it to an alumina crucible, place it in a tubular furnace, and under the protection of a nitrogen atmosphere, use a three-stage gradient heating method at a heating rate of 5°C / min to 1000°C, calcine for 2 hours, cool and grind to obtain solid II.

[0054] S4. Disperse solid II from S3 in ethanol to obtain dispersion I. Dissolve polyacrylic acid in ethanol to obtain solution III. Slowly add dispersion I dropwise to solution III under magnetic stirring. Maintain magnetic stirring at room temperature for 24 hours to obtain dispersion II. The mass ratio of solid II to polyacrylic acid is 1:10.

[0055] S5. Dispersion liquid II in S4 was centrifuged and filtered, washed with deionized water 5 times, and dried at 60° C. for 12 hours to obtain polyacrylic acid-coated N-doped MOFs-derived carbon.

[0056] Comparative Example 1

[0057] The difference from Example 1 is that N-doped MOFs-derived carbon is used without polyacrylic acid coating.

[0058] like Figure 1 As shown, the precursor MOF, ZIF-8, exhibits a smooth, regular dodecahedral structure. High temperatures decompose the organic framework, causing the internal structure to collapse and the surface of the material to shrink, while still maintaining the polyhedral structure of the precursor MOF. Furthermore, the calcination temperature further affects the ratio of defective carbon to graphitic carbon in the material.

[0059] like Figure 2 As shown in the figure, the materials obtained after high temperature calcination have better adsorption properties than the precursor MOF, and as the calcination temperature increases, the material skeleton decomposes more fully, exposing more adsorption sites and enhancing the adsorption capacity of the material. When the calcination temperature reaches above 900℃, the Zn in the material 2+ Gasification occurs, creating more micropores and adsorption sites, further enhancing the material's adsorption capacity. The N-doped MOFs-derived carbon calcined at 1000°C exhibits the best adsorption capacity for 2,4-dichlorophenol and 2,4,6-trichlorophenol.

[0060] pass Figure 3 As can be seen, the N-doped MOF-derived carbon coated with polyacrylic acid exhibits a relatively flat polyhedral morphology. Since the polyacrylic acid coating imparts a large number of carboxyl groups to the material's surface, it is easily wettable in aqueous environments, resulting in excellent dispersibility. Furthermore, the polyacrylic acid coating imparts a high level of negative charge to the material's surface, enhancing its repulsion from inorganic containers and preventing adhesion to the inner walls of the container, facilitating recycling.

[0061] like Figure 4 As shown in the figure, compared with the N-doped MOF-derived carbon calcined at 1000°C, the N-doped MOF-derived carbon coated with polyacrylic acid still maintains similar adsorption capacity. The N-doped MOF-derived carbon coated with polyacrylic acid maintains good adsorption performance over a wide pH range and in the presence of interference from multiple ions and humic acid. The adsorption capacity does not change significantly over four adsorption-desorption cycles, and it exhibits excellent adsorption performance in various practical aqueous environments.

[0062] like Figure 5 As shown in FIG. 1 , the adsorption capacity of 2,4-DCP and 2,4,6-TCP by Example 1 decreases slightly with the increase of adsorption and desorption times, but the adsorption capacity of 2,4,6-TCP is always higher than that of 2,4-DCP, and the adsorption capacity of 2,4,6-TCP is always higher than that of 2,4-DCP. Figure 5 The reusability of Example 1 can be seen in FIG.

[0063] like Figure 6 As shown, Example 1 was put into solutions of different pH values ​​and different salt concentrations to adsorb 2,4-DCP and 2,4,6-TCP. The adsorption capacity of 2,4,6-TCP was higher than that of 2,4-DCP, and remained stable as the pH increased until the pH was greater than 10. When the salt concentration was from 0 to 0.1 mol / L, the adsorption capacity of 2,4,6-TCP and 2,4-DCP remained stable. However, when the salt concentration was from 0 to 0.1 mol / L, the adsorption capacity of 2,4,6-TCP and 2,4-DCP remained stable. 2+ Mg 2+ In the solution, the adsorption capacity of 2,4,6-TCP and 2,4-DCP remained stable, and the adsorption capacity of 2,4,6-TCP and 2,4-DCP remained stable when the HA concentration was as high as 50 mg / L.

[0064] like Figure 7 As shown, the adsorption capacity of 2,4,6-TCP and 2,4-DCP was tested using natural water. When pure water and Xiangjiang River water were tested, the adsorption capacity of 2,4,6-TCP was higher than that of 2,4-DCP. When tap water, lake water and swimming pool water were tested, the adsorption capacity of Example 1 for 2,4-DCP was higher than that of 2,4,6-TCP. When groundwater was tested, the adsorption capacity of Example 1 for the two was the same.

[0065] like Figure 8 The Zeta potential of the N-doped MOFs-derived carbon coated with polyacrylic acid is positive at low pH and negative at high pH. Good dispersibility requires the Zeta potential to be as far away from 0 mV as possible. When the pH is outside the range of 2.5 to 4.5, the dispersibility of the N-doped MOFs-derived carbon coated with polyacrylic acid can be maintained in a relatively good state.

[0066] like Figure 9 As shown, the Zeta potential of N-doped MOFs-derived carbon is positive, while that of polyacrylic acid-coated N-doped MOFs-derived carbon is negative and less than -20 mV, thus maintaining better dispersion.

[0067] like Figures 10-12 As shown, XRD shows the corresponding characteristic peaks of ZIF-8 (2Θ=7.28°, 10.41°, 12.56°, 14.54°, 16.46° and 17.84°), 25° and 44° are attributed to the (002) and (101) crystal planes of graphitic carbon, respectively; the XRD spectra of the polyacrylic acid-coated N-doped MOFs-derived carbon after being placed in water for 15 days and after 4 cycles of use are similar to the XRD spectra of the original polyacrylic acid-coated N-doped MOFs-derived carbon, indicating that the polyacrylic acid-coated N-doped MOFs-derived carbon has high stability.

[0068] like Figure 13As shown in the curves of the removal rate and adsorption capacity of polyacrylic acid coated N-doped MOFs-derived carbon for 2,4-DCP and 2,4,6-TCP relative to time, it can be seen that the removal rates of 2,4-DCP and 2,4,6-TCP reached 94.10% and 98.71% respectively in about 2 minutes, and the adsorption equilibrium was reached in 10 minutes, proving that polyacrylic acid coated N-doped MOFs-derived carbon can meet the requirements of rapid adsorption.

[0069] like Figure 14 As shown, the R of the pseudo-second-order kinetic model fitting is 2 Both are greater than 0.9999, so the pseudo-second-order kinetic model can better describe the adsorption process, which also shows that the rate-limiting step of DBPs adsorption by polyacrylic acid-coated N-doped MOFs-derived carbon is mainly chemical adsorption.

[0070] The adsorption isotherm model of polyacrylic acid-coated N-doped MOF-derived carbon shows that the Freundlish isotherm model is more suitable for describing the adsorption behavior of DBPs by polyacrylic acid-coated N-doped MOF-derived carbon, indicating that the adsorption process is a multi-molecular layer adsorption involving both physical and chemical adsorption. (Forces involved include hydrogen bonding, π-π interactions, electrostatic interactions, and pore size restriction.) This further confirms that both physical and chemical factors contribute to the adsorption. ΔG values ​​are all less than 0, indicating that the adsorption process is spontaneous. The ΔG values ​​for each bisphenol increase with increasing temperature, further confirming that adsorption is favored at lower temperatures. The negative ΔH values, with absolute values ​​all less than 50 kJ / mol, indicate that the adsorption of DBPs by polyacrylic acid-coated N-doped MOF-derived carbon is an exothermic process. The negative ΔS values ​​indicate that the adsorption of DBPs by the material gradually stabilizes with increasing adsorption capacity. The data are shown in Tables 1 and 2.

[0071] Table 1 Langmuir and Freundish adsorption isotherm parameters of DBPs adsorbed on NC-1000@PAA at 298K

[0072]

[0073] Table 2 Thermodynamic parameters of NC-1000@PAA adsorption of DBPs

[0074]

[0075] like Figure 16 As shown in the XPS spectra (a) of NC-1000 and NC1000@PAA, the proportion of O element in NC-1000@PAA increases, proving the successful coating of PAA. The data are shown in Table 3 below:

[0076] Table 3 XPS spectra data of NC-1000 and NC-1000@PAA

[0077] C(％) N(％) O(％) NC-1000 93.73％ 2.82 3.18 NC-1000@PAA 86.08％ 2.77 11.04

[0078] The change data of XPS spectrum (b) of NC-1000@PAA before and after adsorption of DBPs are shown in Table 4 below:

[0079] Table 4 XPS spectrum data of NC-1000@PAA before and after adsorption of DBPs

[0080] C(％) N(％) O(％) Cl(％) NC-1000@PAA 86.08 2.77 11.04 0 DBPs-loaded 81.7 2.22 13.27 2.81

[0081] The adsorption of the target compound is confirmed by an increased proportion of O and the presence of Cl. The C1s spectrum (c) shows a C-Cl bond binding energy of 287 eV, confirming adsorption of the target compound on NC-1000@PAA. The O1s spectrum (d) shows an N-O bond binding energy of 533.9 eV, demonstrating interaction between the N-containing groups in the material and the -OH groups on the DBPs.

[0082] Table 5 Comparison of microscopic parameters of NC1000, NC-1000@PAA or ZIF-8

[0083] NC-1000 NC-1000@PAA ZIF-8 Langmuir surface area <![CDATA[2,815.8624m 2 / g]]> <![CDATA[1,692.7757m 2 / g]]> <![CDATA[1.950.0899m 2 / g]]> Pore ​​volume <![CDATA[1.307266cm 3 / g]]> <![CDATA[0.816774cm 3 / g]]> <![CDATA[0.089611cm 3 / g]]> Aperture 2.9510nm 2.9758nm 1.5462nm

[0084] As shown in the table above, NC-1000@PAA can still maintain a more efficient adsorption effect even though its pore volume and Langmuir surface area are much smaller than those of NC-1000.

[0085] The above-mentioned embodiments only express several implementation methods of the present invention. The description thereof is relatively specific and detailed, but it should not be understood as limiting the scope of the invention patent.

[0086] For ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all fall within the scope of protection of the present invention. Therefore, the scope of protection of the patent of the present invention should be based on the attached claims.

Claims

1. An application of a MOFs-derived carbon material with high adsorption capacity for substituted benzenes in removing chlorophenols from liquids, characterized in that: The MOFs-derived carbon material is a polyacrylic acid-coated N-doped MOFs-derived carbon material, and has an adsorption rate of more than 90% for substituted benzene substances; the zeta potential of the polyacrylic acid-coated N-doped MOFs-derived carbon is negative and less than -20mV; The N-doped MOFs-derived carbon is obtained by calcining ZIF-8 at high temperature.

2. The use according to claim 1, characterized in that The method for preparing the MOFs-derived carbon material having high adsorption capacity for substituted benzene substances comprises the following steps: 1) Preparation of ZIF-8: Pour a methanol solution of dimethylimidazole into a methanol solution of hydrated zinc nitrate at room temperature, stir, let stand, separate the solid and liquid, wash and dry the solid to obtain ZIF-8, wherein the molar ratio of hydrated zinc nitrate to dimethylimidazole is 1:6-10; 2) preparing N-doped MOFs-derived carbon: calcining the ZIF-8 prepared in step 1) at 600-1000° C. for several hours under inert gas protection to obtain the N-doped MOFs-derived carbon; 3) Preparing polyacrylic acid-coated N-doped MOFs-derived carbon: adding the N-doped MOFs-derived carbon prepared in step 2) to a polyacrylic acid aqueous solution, mixing the N-doped MOFs-derived carbon and polyacrylic acid in a mass ratio of 1:8 to 12 for reaction, collecting the precipitate by solid-liquid separation, washing, and drying to obtain the polyacrylic acid-coated N-doped MOFs-derived carbon.

3. The use according to claim 2, characterized in that In step 1), the stirring time is 2.5 to 4 hours, the standing time is 10 to 14 hours, the drying temperature is 55 to 65° C., and the drying time is 10 to 14 hours.

4. The use according to claim 2, characterized in that In step 2), the temperature is raised to 600-1000° C. by a three-stage gradient heating method, the calcination time is 1.5-3 hours, and the inert gas is argon.

5. The use according to claim 2, characterized in that In step 3), the average molecular weight of the polyacrylic acid is 3,000 to 10,000, and the concentration of the polyacrylic acid aqueous solution is 50 wt%.

6. The use according to claim 2, characterized in that The dosage of the polyacrylic acid-coated N-doped MOFs-derived carbon is 0.4 mg / mL; and / or the concentration of pollutants in water is greater than 20 ng / mL; and / or the applicable pH range is 3-9; and / or the applicable temperature is less than 50°C.

7. The use according to any one of claims 1 to 6, characterized in that: The method also includes using chromatography-mass spectrometry to detect the amount of chlorophenol poison adsorbed by the MOFs-derived carbon material.

8. The use according to claim 7, characterized in that The chromatography-mass spectrometry detection conditions are: Chromatographic separation was performed on an Exion LC AC system using a Phenomenex Kinetex Biphenyl 50 × 3.0 mm, 2.6 μm column; Mobile phase A was 5 mM ammonium formate in water, mobile phase B was methanol, and the gradient elution program was as follows: 0–0.5 min, 5% B; 0.5–2 min, 5%–95% B; 2–5 min, 95% B; 5–5.1 min, 95%–5% B; 5.1–7 min, 5% B; the flow rate was 0.4 mL / min, the injection volume was 5 μL, and the column temperature was 40°C. The ion source was atmospheric pressure chemical ionization (APCI) source; the ionization mode was negative ion mode; the ion source temperature was 250°C; the nebulizing gas pressure was 60 psi, the curtain gas pressure was 25 psi, the collision gas pressure was 8 psi, and the mass spectrometry scanning mode was multiple reaction monitoring mode.

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