Preparation method and application of functionalized porous graphene oxide
By controlling the morphology and modifying the surface functional groups of graphene oxide, functionalized porous graphene oxide was prepared, which solved the problems of low removal efficiency and poor selectivity of existing graphene oxide adsorbents for low concentrations of Pb(II), and achieved a high-efficiency and highly selective purification effect for heavy metal wastewater.
Patent Information
- Application Number
- CN202610574002.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-04-28
- Publication Date
- 2026-08-04
AI Technical Summary
Existing graphene oxide adsorbents have low removal efficiency and poor selectivity for low concentrations of Pb(II). The surface electrical structure and steric effect of traditional adsorbents limit their adsorption capacity.
Functionalized porous graphene oxide was prepared by morphology control and surface functional group modification. The carboxyl-COOH groups at the edge of the porous graphene oxide were activated by dicyclohexylcarbodiimide, and MA-type nitrogen functionalized monomers were introduced to form nanoscale pore defects and abundant adsorption active sites.
It achieves a high removal rate of 87%-100% for Pb(II) and has good selectivity and regenerability, making it suitable for the deep purification of low-concentration heavy metal wastewater.
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Figure CN122499774A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of adsorbent technology, specifically relating to a method for preparing functionalized porous graphene oxide and its application. Background Technology
[0002] Lead, as one of the most toxic heavy metals, is characterized by easy migration, easy accumulation and difficulty in degradation. Therefore, the removal of lead pollution from water is of great significance to ecological environment protection and human health.
[0003] Adsorption methods hold great potential in water pollution treatment due to their advantages such as wide availability of adsorbents, simple operation, and no secondary pollution. Adsorbents are diverse, and traditional adsorbents are inexpensive and readily available; however, their high adsorption capacity is often limited by surface electrical structure and steric effects. Graphene oxide (GO), as a novel adsorbent material, is highly favored due to its large specific surface area and abundant oxygen-containing groups. However, it suffers from limited adsorption active sites and poor selectivity. Furthermore, the adsorption active sites of graphene oxide are mainly distributed at the edges of the nanosheets, limiting its adsorption capacity. Summary of the Invention
[0004] To address the shortcomings of the existing technologies, this invention provides a method for preparing functionalized porous graphene oxide and its application by controlling the morphology of graphene oxide and modifying its surface functional groups. Through synergistic optimization of morphology control and surface functional group modification, the problem of low removal efficiency and poor selectivity of existing adsorbents for low concentrations of Pb(II) is solved, thereby achieving deep purification of lead-containing wastewater.
[0005] The specific plan is as follows:
[0006] A method for preparing functionalized porous graphene oxide includes the following steps: using porous graphene oxide PGO, dicyclohexylcarbodiimide DCC, and MA-type nitrogen-functionalized modified monomers as raw materials, reacting them under an inert atmosphere to obtain functionalized porous graphene oxide.
[0007] Specifically, an ethanol solution of porous graphene oxide is prepared, and dicyclohexylcarbodiimide is added. The mixture is reacted at room temperature for 0.5–1 h under an inert atmosphere. Subsequently, a nitrogen-functionalized monomer of the MA class is added, and the mixture is reacted at 50–80 °C for 6–12 h under an inert atmosphere. After the reaction, functionalized porous graphene oxide is obtained. Preferably, the inert atmosphere is nitrogen.
[0008] Furthermore, the MA-type nitrogen-functionalized monomer is selected from at least one of melamine (MA), 2,4-diamino-6-methyl-1,3,5-triazine (CH3-MA), 2-chloro-4,6-diamino-1,3,5-triazine (Cl-MA), and 4',4”-(1,3,5-triazine-2,4,6-triyl)triphenylamine (Aniline-MA).
[0009] Furthermore, the ratio of porous graphene oxide to dicyclohexylcarbodiimide (DCC) is (50~100) mg: (100~150) mg. The dicyclohexylcarbodiimide (DCC) is used to activate the carboxyl-COOH groups at the edges of the porous graphene oxide (PGO).
[0010] Furthermore, the ratio of porous graphene oxide to MA-type nitrogen-functionalized modified monomers is (50~100) mg: (1~5) mmol.
[0011] Preferably, the ratio of porous graphene oxide to ethanol is (50~100) mg: (50~100) mL.
[0012] Furthermore, the preparation process of porous graphene oxide is as follows: under a closed environment, hydrogen peroxide (H2O2), ammonia water, and graphene oxide are reacted at 30~70℃ for 2~6h to obtain porous graphene oxide (PGO).
[0013] Preferably, the mixing ratio of graphene oxide to hydrogen peroxide is (50~100) mg: (0.0029~0.0150) mol; the mixing ratio of graphene oxide to ammonia is (50~100) mg: (0.0143~0.0714) mol.
[0014] Preferably, the concentration of hydrogen peroxide is 5%, and the concentration of ammonia is 25-28%.
[0015] The functionalized porous graphene oxide prepared according to the aforementioned method can achieve a Pb(II) removal rate of 87%-100% in the adsorption of Pb(II).
[0016] Compared with existing technologies, the beneficial effects are as follows:
[0017] This invention uses graphene oxide (GO) as a raw material and introduces nanoscale pore defects through an oxidation etching method to prepare porous graphene oxide (PGO). Subsequently, using MA-type compounds as nitrogen-functionalized monomers, a functionalized porous graphene oxide adsorbent material was synthesized. This adsorbent material exhibits excellent adsorption performance for Pb(II), with a Pb(II) removal rate of 87%-100%, and also demonstrates high specificity and good regenerability. Attached Figure Description
[0018] Figure 1ab are TEM images of porous graphene oxide (PGO) at magnifications of 10000 and 15000, respectively.
[0019] Figure 2 FT-IR plots of GO and PGO;
[0020] Figure 3 a is the XPS full spectrum of PGO-Cl-MA; Figure 3 b is the SEM image of PGO-Cl-MA;
[0021] Figure 4 The graph shows the relationship between PGO-Cl-MA dosage and Pb(II) adsorption.
[0022] Figure 5 The diagram shows the ion selectivity characterization of PGO-Cl-MA.
[0023] Figure 6 This is a characterization diagram of the recyclability of PGO-Cl-MA. Detailed Implementation
[0024] The embodiments of the present invention will be described in further detail below. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention. Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.
[0025] Example
[0026] A method for preparing functionalized porous graphene oxide includes the following steps:
[0027] Prepare 80 mL of a 1 mg / mL GO solution using deionized water and GO. Then, slowly add 5 mL of hydrogen peroxide (5% H2O2) and 5 mL of ammonia (25% NH4OH) to the GO solution using a pipette. To prevent the volatilization of H2O2 and NH4OH, immediately seal the mouth of the beaker with plastic wrap. Then, place the sealed beaker in a water bath, set the temperature to 50°C, and start the magnetic stirrer. Stir continuously for 5 hours to obtain PGO.
[0028] Take 60 mg of PGO powder and place it in a 250 mL three-necked flask. Add 60 mL of ethanol to the flask and sonicate for 15 min to ensure that PGO is fully dissolved in the ethanol. Then, weigh 130 mg of dicyclohexylcarbodiimide (DCC) and add it to the PGO solution. React under nitrogen protection using a magnetic stirrer for 1 h. Then, add 1 mmol of 2-chloro-4,6-diamino-1,3,5-triazine (Cl-MA) to the reaction system. Under nitrogen protection, reflux the reaction at 50 °C for 10 h. After the reaction is complete, allow the system to cool naturally to room temperature. Use ethanol as a washing agent and centrifuge at 1000 rpm for 15 min each time. Finally, place the obtained final product in a vacuum drying oven at 60 °C to dry it to obtain PGO-Cl-MA.
[0029] according to Figure 1 As can be seen from ab, a large number of porous defects were successfully formed on the PGO surface, increasing the number of its adsorption active sites. Through FT-IR characterization of GO and PGO, the FT-IR spectrum of PGO shows a peak at 3455 cm⁻¹. -1 The broad absorption peak at 1726 cm⁻¹ is due to the stretching vibration of the OH bond on the hydroxyl group; the peak at 1726 cm⁻¹ is due to the stretching vibration of the OH bond on the hydroxyl group. -1 and 1322cm -1 The characteristic peaks at the point are the stretching vibration peak of the -C=O group on the carboxyl group and the bending vibration peak of the CO bond; the results indicate that the main oxygen-containing groups distributed on the PGO surface are -OH and -COOH. Figure 2 ).
[0030] SEM characterization of the material showed that PGO-Cl-MA maintained its lamellar structure after modification, and its roughness increased, indicating that the morphology of PGO was not changed during the nitrogen functionalization modification process. XPS characterization revealed a characteristic binding energy peak of NC=O in the 399.5-400.8 eV range (slightly shifted due to different substituents), further confirming the presence of amide bonds. Figure 3 ab).
[0031] Five 250 mL aliquots of Pb(II) solution with an initial concentration of 5 mg / L were prepared in 250 mL beakers. The pH of the solution was adjusted to 6 with NaOH and HNO3. 10, 20, 30, 40, and 50 mg of PGO-Cl-MA were added as adsorbents, respectively. 2 mL of the supernatant was collected at 0, 0.17, 0.5, 1, 1.5, 2, 3.5, 5, 7, and 9 h, filtered through a 0.45 μm filter membrane, and placed in centrifuge tubes. The Pb(II) concentration was determined using a flame atomic absorption spectrophotometer. Figure 4The graph shows the relationship between PGO-Cl-MA dosage and Pb(II) adsorption. Through adsorption data analysis, PGO-Cl-MA exhibits excellent adsorption performance for Pb(II), with a Pb(II) removal rate of 87%-100%.
[0032] To investigate the ion selectivity of PGO-Cl-MA, adsorption experiments were conducted on Fe(III), Ni(II), Cu(II), Mg(II), Mn(II), Zn(II), and Ag(I) at the same concentration (2 mg / L) under four optimal adsorption conditions (PGO-Cl-MA dosage 10 mg, pH=5). 2 mL of the mixed solution was taken at 0 and 9 h, filtered through a 0.45 μm filter membrane, and placed in centrifuge tubes. The concentration was measured using a flame atomic absorption spectrophotometer, and the removal rate of each metal ion by PGO-Cl-MA was calculated. Figure 5 The diagram shows the ion selectivity of PGO-Cl-MA. Other metal ions have little interference with the adsorption of Pb(II) by the adsorbent PGO-Cl-MA.
[0033] To investigate the regeneration performance of PGO-Cl-MA, under four optimal adsorption conditions (PGO-Cl-MA dosage of 10 mg, initial concentration of 2 mg / L, and pH=5), the adsorbent was desorbed using 1 mol / L HNO3. The adsorption-desorption cycle was repeated five times. At 0 and 9 h, 2 mL of the mixed solution was taken, filtered through a 0.45 μm filter membrane, and placed in centrifuge tubes. The concentration was measured using a flame atomic absorption spectrophotometer. The removal rate of Pb(II) by PGO-Cl-MA after each adsorption-desorption cycle was calculated. Figure 6 The image shows the recyclability of PGO-Cl-MA. PGO-Cl-MA has relatively good recyclability, with the removal rate decreasing by only 9.88% after 5 regenerations.
[0034] Adsorption kinetics and adsorption isotherm fitting analysis showed that the adsorption of Pb(II) by the adsorbent conformed to the Langmuir adsorption isotherm model, indicating that the adsorption process was dominated by monolayer chemisorption and was entirely spontaneous adsorption.
[0035] The PGO-Cl-MA composite material synthesized in this invention provides a new approach for the design of Pb(II) adsorbents. The structure-activity relationship between the material structure and adsorption performance was studied, and its application prospects in removing low-concentration heavy metal wastewater were verified.
[0036] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A method for preparing functionalized porous graphene oxide, characterized in that, Includes the following steps: Functionalized porous graphene oxide was obtained by reacting porous graphene oxide (PGO), dicyclohexylcarbodiimide (DCC), and MA-type nitrogen-functionalized modified monomers under an inert atmosphere.
2. The preparation method according to claim 1, characterized in that, An ethanol solution of porous graphene oxide was prepared, and dicyclohexylcarbodiimide was added. The reaction was carried out under an inert atmosphere for 0.5-1 h. Subsequently, a nitrogen-functionalized monomer of the MA class was added, and the reaction was carried out at 50-80 °C for 6-12 h under an inert atmosphere. Functionalized porous graphene oxide was obtained after the reaction was completed.
3. The preparation method according to claim 2, characterized in that, MA-type nitrogen-functionalized monomers are selected from at least one of melamine, 2,4-diamino-6-methyl-1,3,5-triazine, 2-chloro-4,6-diamino-1,3,5-triazine, and 4',4”-(1,3,5-triazine-2,4,6-triyl)triphenylamine.
4. The preparation method according to claim 2, characterized in that, The ratio of porous graphene oxide to dicyclohexylcarbodiimide is (50~100) mg: (100~150) mg.
5. The preparation method according to claim 2, characterized in that, The ratio of porous graphene oxide to MA-type nitrogen-functionalized modified monomers is (50~100) mg: (1~5) mmol.
6. The preparation method according to claim 2, characterized in that, The ratio of porous graphene oxide to ethanol is (50~100) mg: (50~100) mL.
7. The preparation method according to claim 1, characterized in that, The preparation process of porous graphene oxide is as follows: under a closed environment, hydrogen peroxide (H2O2), ammonia water and graphene oxide are reacted at 30~70℃ for 2~6h to obtain porous graphene oxide (PGO).
8. The preparation method according to claim 7, characterized in that, The mixing ratio of graphene oxide to hydrogen peroxide is (50~100) mg: (0.0029~0.0150) mol; the mixing ratio of graphene oxide to ammonia is (50~100) mg: (0.0143~0.0714) mol.
9. The application of functionalized porous graphene oxide prepared by any one of the preparation methods according to claims 1 to 8 in the adsorption of Pb(II).