A compressible sulfonated graphene aerogel adsorbent material, its preparation method, and its application.

Abstract

This invention discloses a compressible sulfonated graphene aerogel adsorbent material, its preparation method, and its application, belonging to the technical field of functional graphene aerogel preparation. The compressible sulfonated graphene aerogel is used for the selective adsorption of highly polar extractants in solvent extraction processes for phenol extraction. The preparation method first prepares a graphene oxide dispersion, then grafts sulfonic acid groups onto the graphene oxide using diazonium aminobenzenesulfonic acid as an intermediate medium; subsequently, anhydrous ethylenediamine is used as a crosslinking agent to prepare a hydrogel through a hydrothermal reaction, and finally, freeze-drying yields the sulfonated graphene aerogel material. This invention, by pretreating and incorporating sulfonic acid groups into the carbon aerogel framework, significantly improves the aerogel's adsorption capacity for highly polar extractants; it lays a solid foundation for the adsorption and separation of highly polar extractants, and the preparation method involved is low-cost, highly operable, and scalable, indicating promising application prospects.

Description

Technical Field

[0001] This invention relates to the field of aerogel materials for highly polar extractants in the adsorption-separation solvent extraction process for phenol extraction and their preparation technology, specifically to a compressible sulfonated graphene aerogel and its preparation method. Background Technology

[0002] Phenolic raw materials used in industry are mainly found in the processing of coal tar, petroleum, and biomass pyrolysis oil. The traditional alkaline washing process for phenol extraction involves reacting sodium hydroxide with phenolic compounds to form sodium phenolate, which is then separated. However, this process consumes large amounts of strong acids and bases and generates phenol-containing wastewater, causing environmental pollution. In contrast, the solvent extraction process selects a suitable solvent to react with phenolic compounds. It utilizes the high solubility of the extractant in phenolic compounds but low solubility in the oil phase to achieve the extraction and separation of phenolic compounds under appropriate conditions. This process is generally simple and less prone to secondary pollution. Currently, highly polar extractants such as amides, esters, and ethers are commonly used to separate phenolic compounds from phenolic oils. However, based on the principles of acid-base coordination and hydrogen bonding, these extractants typically form stable binary mixtures with phenolic compounds, making it difficult for conventional separation methods to remove the extractant from multiple phenols. For example, multi-stage distillation cannot completely separate the azeotrope formed by the two, and the equipment cost is high and the energy consumption is large; while commercial adsorbents such as activated carbon, alumina, and zeolite cannot selectively adsorb these highly polar extractants. Therefore, a new adsorbent that is low-cost and highly efficient is needed. Summary of the Invention

[0003] Graphene aerogels are three-dimensional porous network structures formed by stacking and connecting two-dimensional graphene sheets. They not only retain the excellent physicochemical properties of two-dimensional graphene but also possess characteristics such as low density, high porosity, stable mechanical strength, flexible structural control, and strong adsorption performance, demonstrating significant application value in the separation field. Achieving multifunctionality of graphene aerogels requires introducing modifying reagents to replace the original oxygen-containing functional groups in their two-dimensional precursors through a series of reactions. For example, by utilizing media with stronger electron-withdrawing effects (such as sulfonic acid groups, nitro groups, and carboxyl groups), some highly polar organic impurities can be electrostatically adsorbed and separated, enabling graphene aerogels to function as selective adsorbents. Therefore, using sulfonated graphene aerogels with a certain degree of compressibility as adsorption carriers to effectively remove highly polar extractants from solvent extraction systems for phenol extraction is of great significance for advancing its practical applications.

[0004] The purpose of this invention is to provide a compressible sulfonated graphene aerogel adsorbent material and its preparation method. The resulting compressible sulfonated graphene aerogel material can effectively adsorb and separate strongly polar extractants in the solvent extraction process for phenol extraction. Furthermore, the preparation method of this aerogel adsorbent material has low cost, strong operability, and can be prepared on a large scale.

[0005] To achieve the above objectives, the present invention provides the following technical solution: A compressible sulfonated graphene aerogel adsorbent material and its preparation method include the following steps: (1) Dissolve aminobenzenesulfonic acid powder in sodium hydroxide solution, then add nitrite and concentrated strong acid, and carry out diazotization reaction under ice bath stirring to generate aminobenzenesulfonic acid diazonium salt. (2) The obtained diazonium salt of aminobenzenesulfonic acid was added dropwise to a uniformly dispersed graphite oxide dispersion and sulfonated under ice bath stirring to generate a sulfonated graphite oxide dispersion. (3) The obtained sulfonated graphite oxide dispersion was centrifuged and washed, and then prepared into a uniform 2 ~ 6 mg / mL dispersion and stored at low temperature. (4) After mixing the prepared sulfonated graphene oxide dispersion with anhydrous ethylenediamine, a hydrothermal reaction is carried out to synthesize sulfonated graphene hydrogel. (5) The obtained sulfonated graphene hydrogel was purified by immersing it in deionized water and then freeze-dried to obtain a compressible sulfonated graphene aerogel adsorbent material.

[0006] Specifically, the aminobenzenesulfonic acid in step (1) includes one of o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, and p-aminobenzenesulfonic acid. Preferably, the aminobenzenesulfonic acid is p-aminobenzenesulfonic acid.

[0007] Specifically, the temperature of the sodium hydroxide solution in step (1) is 35 ~ 50 ℃, and the mass fraction of sodium hydroxide is 2 ~ 5%.

[0008] Specifically, the nitrite in step (1) is one of sodium nitrite, potassium nitrite, butyl nitrite, and amyl nitrite. Preferably, the nitrite is sodium nitrite.

[0009] Specifically, the concentrated strong acid in step (1) is one of hydrochloric acid, hydrobromic acid, tetrafluoroboric acid, perchloric acid, trifluoroacetic acid, and methanesulfonic acid. Preferably, the concentrated strong acid is hydrochloric acid.

[0010] Specifically, in step (1), the molar ratio of aminobenzenesulfonic acid to nitrite is 1:(1 ~ 1.5), and the molar ratio of aminobenzenesulfonic acid to concentrated strong acid is 1:(2.5 ~ 5).

[0011] Specifically, in step (1), the diazotization reaction temperature is 0 ~ 10 ℃, and the diazotization reaction time is 15 ~ 25 min. Preferably, the diazotization reaction time is 15 min.

[0012] Specifically, the graphene oxide dispersion in step (2) is prepared by one of the Brodie method, the Staudenmaier method, or the modified Hummer method, with a concentration of 10-20 mg / mL and a storage temperature of 0-8℃. Preferably, the graphene oxide dispersion is prepared by the modified Hummer method, with a graphene oxide concentration of 10 mg / mL.

[0013] Specifically, the mass ratio of the graphite oxide dispersion to aminobenzenesulfonic acid in step (2) is 1:(1 ~ 6).

[0014] Specifically, the sulfonation treatment temperature in step (2) is 0 ~ 10 ℃, and the sulfonation treatment time is 2 ~ 6 h. Preferably, the sulfonation treatment time is 3.5 h.

[0015] Specifically, the centrifugal washing step of the sulfonated graphite oxide dispersion in step (3) includes: (a) Centrifuge the sulfonated graphite oxide dispersion obtained from the reaction at a speed of 8000 ~ 9000 r / min for 10 ~ 15 min, separate the supernatant and retain the lower brown precipitate; (b) Add an appropriate amount of deionized water to the upper layer of the precipitate and mix evenly. Centrifuge at 7000-8000 r / min for 5-10 min, separate the supernatant and retain the lower brown precipitate. (c) Repeat step (b) 3 to 6 times until the pH of the supernatant is 5 to 6.

[0016] Specifically, the dispersant in the sulfonated graphite oxide dispersion in step (3) is one of ultrapure water, deionized water, dimethylformamide (DMF), N-methylpyrrolidone (NMP), and ethylene glycol, and the concentration of the sulfonated graphite oxide dispersion is 2-5 mg / mL. Preferably, the dispersant in the sulfonated graphite oxide dispersion is deionized water, and the concentration of the sulfonated graphite oxide dispersion is 3 mg / mL.

[0017] Specifically, in step (4), the volume ratio of the sulfonated graphite oxide dispersion to anhydrous ethylenediamine is 500:(1~5), and the mixing time is 10~20 min. Preferably, the volume ratio of the sulfonated graphite oxide dispersion to anhydrous ethylenediamine is 500:3.

[0018] Specifically, the hydrothermal reaction temperature in step (4) is 120~200 ℃, and the hydrothermal reaction time is 10~15 h. Preferably, the hydrothermal reaction temperature is 180 ℃, and the reaction time is 12 h.

[0019] Specifically, the freeze drying in step (5) involves freezing the food in a refrigerator and then transferring it to a freeze dryer at -50 to -70 ℃ for 36 to 96 hours.

[0020] The aerogel adsorbent material is used for the separation of highly polar extractants in crude phenol oil.

[0021] The highly polar extractant is a highly polar extractant containing amides, esters, or ethers.

[0022] The specific separation steps are as follows: (1) Add an appropriate amount of crude phenolic oil treated by solvent extraction to a beaker and record the total mass as M0; place any volume of dried sulfonated graphene aerogel material into it and remove it every 2 to 5 minutes, and record the remaining total mass as M. n (For example, M1 represents the remaining mass after the first extraction) and calculate the cumulative absorbed mass of crude phenolic oil ΔM. n (△M) n =M0-M n ), until △M n Approaching stability. Then, plotting absorption time as the x-axis and the cumulative absorbed mass ΔM... n Plotting the absorption equilibrium curve on the ordinate, we obtain the maximum absorption value M for this volume of aerogel. max .

[0023] (2) Place the same dry aerogel as in step (1) vertically into the beaker, and then drop a mass of M onto its surface. max The crude phenolic oil was then sealed in a beaker with an organic membrane and placed in the dark for adsorption treatment.

[0024] (3) Take out the aerogel from step (2) and put it into the empty tube of a special quartz syringe with a built-in stainless steel filter. Use the quartz push rod to squeeze the aerogel and collect the absorbed phenolic oil. Then use gas chromatography-mass spectrometry to quantitatively detect the content of phenolic compounds.

[0025] Specifically, in step (2), the adsorption treatment temperature of the sulfonated graphene aerogel on the highly polar extractant in crude phenol oil is 40~60 ℃, and the adsorption treatment time is 20~40 min. Preferably, the adsorption treatment temperature is 50 ℃ and the adsorption treatment time is 30 min.

[0026] The present invention has the following excellent effects: The present invention provides a compressible sulfonated graphene aerogel adsorbent material and its preparation method. First, a graphene oxide dispersion is prepared. Then, sulfonic acid groups are grafted onto the graphene oxide using diazonium aminobenzenesulfonic acid as an intermediate medium. Then, anhydrous ethylenediamine is used as a crosslinking agent to prepare a hydrogel through a hydrothermal reaction. Finally, the sulfonated graphene aerogel material is obtained by freeze-drying.

[0027] The resulting compressible sulfonated graphene aerogel material has adjustable volume, regular morphology, smooth surface, stable mechanical properties, and abundant pore structure, which can effectively adsorb and separate strongly polar extractants in the solvent extraction process for phenol extraction. The sulfonation of graphene aerogel is mainly achieved by grafting sulfonic acid groups onto the surface of graphene oxide through the reaction of diazonium salt of aminobenzenesulfonic acid at low temperature. To make it compressible, anhydrous ethylenediamine, a crosslinking agent, can be added. Through the grafting and removal reaction, the graphene oxide sheets are tightly connected and the conjugated regions on the surface are repaired, forming a more stable porous structure under the π~π conjugated system and hydrophobic interaction.

[0028] The sulfonated aerogels effectively separated highly polar extractants such as amides, esters, and ethers: the phenolic compound content in crude phenolic oil containing amide extractants increased from 60 wt% to 89 wt%, with an adsorption rate of 72.5%; the phenolic compound content in crude phenolic oil containing ester extractants increased from 63 wt% to 93 wt%, with an adsorption rate of 75%; and the phenolic compound content in crude phenolic oil containing ether extractants increased from 61 wt% to 87 wt%, with an adsorption rate of 65%, indicating superior adsorption performance for ester extractants. In contrast, activated carbon, alumina, and zeolite, three commercially available powdered adsorbents, showed poor adsorption performance for highly polar extractants such as amides, esters, and ethers, with almost no change in the phenolic compound content in the crude phenolic oil before and after adsorption treatment. In comparison, the sulfonated aerogels prepared in this invention exhibit high efficiency and selectivity in the adsorption and separation of these three highly polar extractants. Although trace amounts of extractant remain in the treated crude phenolic oil, these levels are unmatched by commercial powdered adsorbents. The preparation method of this aerogel adsorbent material is low-cost, highly operable, and can be mass-produced, and it is expected to have a good application prospect. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0030] Figure 1 This is a digital photograph of the aerogel adsorbent material prepared in Example 3.

[0031] Figure 2 This is a digital photograph of the aerogel adsorbent material prepared in Example 5.

[0032] Figure 3 This is the absorption equilibrium curve of crude phenolic oil by the aerogel adsorbent material prepared in Example 3.

[0033] Figure 4 This is the absorption equilibrium curve of crude phenolic oil by the aerogel adsorbent material prepared in Example 5.

[0034] Figure 5 This is a graph showing the content of phenolic compounds in crude phenolic oil containing highly polar extractants after treatment with different adsorbents. Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0036] This invention discloses a compressible sulfonated graphene aerogel adsorbent material, its preparation method, and its application.

[0037] To better understand the present invention, the following embodiments are provided for further detailed description of the present invention, but they should not be construed as limiting the present invention. Any non-essential improvements and adjustments made by those skilled in the art based on the above-described invention are also considered to fall within the protection scope of the present invention.

[0038] The technical solution of the present invention will be further described below with reference to specific embodiments. Example 1

[0039] (1) Weigh 0.6 g of p-aminobenzenesulfonic acid and dissolve it completely in 15 mL of 2 wt% sodium hydroxide solution at 40 °C. Then add 0.24 g of sodium nitrite and stir to dissolve it completely. Place the solution in an ice bath and stir while adding 1 mL of concentrated hydrochloric acid. Then react for 15 min to obtain p-aminobenzenesulfonic acid diazonium salt.

[0040] (2) Take 30 mL of 10 mg / mL graphite oxide dispersion, place it in an ice bath and stir while adding diazonium salt of p-aminobenzenesulfonic acid dropwise, and then react for 3.5 h to obtain sulfonated graphite oxide dispersion.

[0041] (3) The obtained sulfonated graphite oxide dispersion was centrifuged and washed: First, centrifuged at 8500 r / min for 10 min, separated the supernatant and retained the lower brown precipitate; then, an appropriate amount of deionized water was added and the precipitate was evenly dispersed, centrifuged at 8000 r / min for 5 min, separated the supernatant and retained the lower brown precipitate, and then repeated 3 times until the pH of the supernatant was about 6. After centrifugation, the precipitate was collected in a 100 mL graduated cylinder and deionized water was added until the maximum mark was reached, then the turbid liquid was taken out and stirred to make it evenly dispersed, to obtain a 3 mg / mL sulfonated graphite oxide ink dispersion.

[0042] (4) Measure 10 mL of 3 mg / mL sulfonated graphene oxide ink dispersion and 60 μL of anhydrous ethylenediamine, stir for 15 min to mix thoroughly, and then carry out a hydrothermal reaction at 180 ℃ for 12 h. After it cools naturally to room temperature, sulfonated graphene hydrogel is obtained.

[0043] (4) The sulfonated graphene hydrogel was purified by immersing it in deionized water, the hydrogel was taken out and frozen, and then dried in a freeze dryer for 36 h to obtain the compressible sulfonated graphene aerogel material. Example 2

[0044] (1) Weigh 0.9 g of p-aminobenzenesulfonic acid and dissolve it completely in 15 mL of 2 wt% sodium hydroxide solution at 40 °C. Then add 0.36 g of sodium nitrite and stir to dissolve it completely. Place the solution in an ice bath and stir while adding 1.5 mL of concentrated hydrochloric acid. Then react for 15 min to obtain p-aminobenzenesulfonic acid diazonium salt.

[0045] (2) Take 30 mL of 10 mg / mL graphite oxide dispersion, place it in an ice bath and stir while adding diazonium salt of p-aminobenzenesulfonic acid dropwise, and then react for 3.5 h to obtain sulfonated graphite oxide dispersion.

[0046] (3) The obtained sulfonated graphite oxide dispersion was centrifuged and washed: First, centrifuged at 8500 r / min for 10 min, separated the supernatant and retained the lower brown precipitate; then, an appropriate amount of deionized water was added and the precipitate was evenly dispersed, centrifuged at 8000 r / min for 5 min, separated the supernatant and retained the lower brown precipitate, and then repeated 4 times until the pH of the supernatant was about 6. After centrifugation, the precipitate was collected in a 100 mL graduated cylinder and deionized water was added until the maximum mark was reached, then the turbid liquid was taken out and stirred to make it evenly dispersed, to obtain a 3 mg / mL sulfonated graphite oxide ink dispersion.

[0047] (4) Measure 10 mL of 3 mg / mL sulfonated graphene oxide ink dispersion and 60 μL of anhydrous ethylenediamine, stir for 15 min to mix thoroughly, and then carry out a hydrothermal reaction at 180 ℃ for 12 h. After it cools naturally to room temperature, sulfonated graphene hydrogel is obtained.

[0048] (5) The sulfonated graphene hydrogel was purified by immersing it in deionized water, the hydrogel was taken out and frozen, and then dried in a freeze dryer for 36 h to obtain the compressible sulfonated graphene aerogel material. Example 3

[0049] (1) Weigh 1.2 g of p-aminobenzenesulfonic acid and dissolve it completely in 15 mL of 2 wt% sodium hydroxide solution at 45 ℃. Then add 0.48 g of sodium nitrite and stir to dissolve it completely. Place the solution in an ice bath and stir while adding 2 mL of concentrated hydrochloric acid. Then react for 15 min to obtain p-aminobenzenesulfonic acid diazonium salt.

[0050] (2) Take 30 mL of 10 mg / mL graphite oxide dispersion, place it in an ice bath and stir while adding diazonium salt of p-aminobenzenesulfonic acid dropwise, and then react for 3.5 h to obtain sulfonated graphite oxide dispersion.

[0051] (3) The obtained sulfonated graphite oxide dispersion was centrifuged and washed: First, centrifuged at 8500 r / min for 10 min, separated the supernatant and retained the lower brown precipitate; then, an appropriate amount of deionized water was added and the precipitate was evenly dispersed, centrifuged at 8000 r / min for 5 min, separated the supernatant and retained the lower brown precipitate, and then repeated 5 times until the pH of the supernatant was about 6. After centrifugation, the precipitate was collected in a 100 mL graduated cylinder and deionized water was added until the maximum mark was reached, then the turbid liquid was taken out and stirred to make it evenly dispersed, to obtain a 3 mg / mL sulfonated graphite oxide ink dispersion.

[0052] (4) Measure 10 mL of 3 mg / mL sulfonated graphene oxide ink dispersion and 60 μL of anhydrous ethylenediamine, stir for 15 min to mix thoroughly, and then carry out a hydrothermal reaction at 180 ℃ for 12 h. After it cools naturally to room temperature, sulfonated graphene hydrogel is obtained.

[0053] (5) The sulfonated graphene hydrogel was purified by immersing it in deionized water, the hydrogel was taken out and frozen, and then dried in a freeze dryer for 36 h to obtain the compressible sulfonated graphene aerogel material. Example 4

[0054] (1) Weigh 1.5 g of p-aminobenzenesulfonic acid and dissolve it completely in 15 mL of 2 wt% sodium hydroxide solution at 45 ℃. Then add 0.6 g of sodium nitrite and stir to dissolve it completely. Place the solution in an ice bath and stir while adding 2.5 mL of concentrated hydrochloric acid. Then react for 15 min to obtain p-aminobenzenesulfonic acid diazonium salt.

[0055] (2) Take 30 mL of 10 mg / mL graphite oxide dispersion, place it in an ice bath and stir while adding diazonium salt of p-aminobenzenesulfonic acid dropwise, and then react for 3.5 h to obtain sulfonated graphite oxide dispersion.

[0056] (3) The obtained sulfonated graphite oxide dispersion was centrifuged and washed: First, centrifuged at 8500 r / min for 10 min, separated the supernatant and retained the lower brown precipitate; then, an appropriate amount of deionized water was added and the precipitate was evenly dispersed, centrifuged at 8000 r / min for 5 min, separated the supernatant and retained the lower brown precipitate, and then repeated 6 times until the pH of the supernatant was about 6. After centrifugation, the precipitate was collected in a 100 mL graduated cylinder and deionized water was added until the maximum mark was reached, then the turbid liquid was taken out and stirred to make it evenly dispersed, to obtain a 3 mg / mL sulfonated graphite oxide ink dispersion.

[0057] (4) Measure 10 mL of 3 mg / mL sulfonated graphene oxide ink dispersion and 60 μL of anhydrous ethylenediamine, stir for 15 min to mix thoroughly, and then carry out a hydrothermal reaction at 180 ℃ for 12 h. After it cools naturally to room temperature, sulfonated graphene hydrogel is obtained.

[0058] (5) The sulfonated graphene hydrogel was purified by immersing it in deionized water, the hydrogel was taken out and frozen, and then dried in a freeze dryer for 36 h to obtain the compressible sulfonated graphene aerogel material. Example 5

[0059] (1) Weigh 0.9 g of p-aminobenzenesulfonic acid and dissolve it completely in 15 mL of 2 wt% sodium hydroxide solution at 40 °C. Then add 0.36 g of sodium nitrite and stir to dissolve it completely. Place the solution in an ice bath and stir while adding 1.5 mL of concentrated hydrochloric acid. Then react for 15 min to obtain p-aminobenzenesulfonic acid diazonium salt.

[0060] (2) Take 30 mL of 10 mg / mL graphite oxide dispersion, place it in an ice bath and stir while adding diazonium salt of p-aminobenzenesulfonic acid dropwise, and then react for 3.5 h to obtain sulfonated graphite oxide dispersion.

[0061] (3) The obtained sulfonated graphite oxide dispersion was centrifuged and washed: First, centrifuged at 8500 r / min for 10 min, separated the supernatant and retained the lower brown precipitate; then, an appropriate amount of deionized water was added and the precipitate was evenly dispersed, centrifuged at 8000 r / min for 5 min, separated the supernatant and retained the lower brown precipitate, and then repeated 4 times until the pH of the supernatant was about 6. After centrifugation, the precipitate was collected in a 100 mL graduated cylinder and deionized water was added until the maximum mark was reached, then the turbid liquid was taken out and stirred to make it evenly dispersed, to obtain a 3 mg / mL sulfonated graphite oxide ink dispersion.

[0062] (4) Measure 40 mL of 3 mg / mL sulfonated graphene oxide ink dispersion and 240 μL of anhydrous ethylenediamine, stir for 20 min to mix thoroughly, and then carry out a hydrothermal reaction at 180 ℃ for 12 h. After it cools naturally to room temperature, sulfonated graphene hydrogel is obtained.

[0063] (5) The sulfonated graphene hydrogel was purified by immersing it in deionized water, the hydrogel was taken out and frozen, and then dried in a freeze dryer for 48 h to obtain a compressible sulfonated graphene aerogel material. Example 6

[0064] (1) Weigh 0.9 g of p-aminobenzenesulfonic acid and dissolve it completely in 15 mL of 2 wt% sodium hydroxide solution at 40 °C. Then add 0.36 g of sodium nitrite and stir until it is completely dissolved. Place the solution in an ice bath and stir while adding 2.5 mL of concentrated hydrochloric acid. Then react for 15 min to obtain p-aminobenzenesulfonic acid diazonium salt.

[0065] (2) Take 30 mL of 10 mg / mL graphite oxide dispersion, place it in an ice bath and stir while adding diazonium salt of p-aminobenzenesulfonic acid dropwise, and then react for 3.5 h to obtain sulfonated graphite oxide dispersion.

[0066] (3) The obtained sulfonated graphite oxide dispersion was centrifuged and washed: First, centrifuged at 8500 r / min for 10 min, separated the supernatant and retained the lower brown precipitate; then, an appropriate amount of deionized water was added and the precipitate was evenly dispersed, centrifuged at 8000 r / min for 5 min, separated the supernatant and retained the lower brown precipitate, and then repeated 4 times until the pH of the supernatant was about 6. After centrifugation, the precipitate was collected in a 100 mL graduated cylinder and deionized water was added until the maximum mark was reached, then the turbid liquid was taken out and stirred to make it evenly dispersed, to obtain a 3 mg / mL sulfonated graphite oxide ink dispersion.

[0067] (4) Measure 80 mL of 3 mg / mL sulfonated graphene oxide ink dispersion and 480 μL of anhydrous ethylenediamine, stir for 20 min to mix thoroughly, and then carry out hydrothermal reaction at 180 ℃ for 12 h. After it cools naturally to room temperature, sulfonated graphene hydrogel is obtained.

[0068] (5) The sulfonated graphene hydrogel was purified by immersing it in deionized water, the hydrogel was taken out and frozen, and then dried in a freeze dryer for 72 h to obtain the compressible sulfonated graphene aerogel material.

[0069] Example 7: Plotting the Absorption Equilibrium Curve 1. Main materials The sulfonated graphene aerogel prepared in Example 3 (see Example 3) Figure 1 ); sulfonated graphene aerogel prepared in Example 5 (see Example 5) Figure 2 ); crude phenolic oil treated by solvent extraction.

[0070] 2. Main methods Add an appropriate amount of crude phenolic oil treated by solvent extraction to a beaker and record the total mass as M0; place the dried sulfonated graphene aerogel materials prepared in Examples 3 and 5 into the beaker and remove them at intervals of 2 min and 5 min, respectively, and record the remaining total mass as M. n And calculate the cumulative absorbed mass ΔM of crude phenolic oil. n until △M n Approaching stability. Then, plotting absorption time as the x-axis and the cumulative absorbed mass ΔM... n Plotting the absorption equilibrium curve with the ordinate as the vertical axis yields the maximum absorption value M for both aerogels. max .

[0071] 3. Results Analysis The sulfonated graphene aerogel material (0.02 g by mass) prepared in Example 3, such as Figure 3 As shown, the cumulative absorption value increases slowly with increasing absorption time and reaches its maximum at 30 min, indicating that the saturated absorption capacity of this dry aerogel for crude phenolic oil is 5 g; the sulfonated graphene aerogel material prepared in Example 5 (mass 0.03 g), such as... Figure 4As shown, the cumulative absorption value increases rapidly with increasing absorption time, reaching its maximum value at 15 minutes, indicating that the saturated absorption capacity of this dry aerogel for crude phenolic oil is 10 g. This is due to the difference in volume between the two sulfonated aerogels: the small-volume dry aerogel material in Example 3 has a smaller average pore size, resulting in a slower permeation rate of crude phenolic oil and a longer time required to reach saturation absorption; while the large-volume dry aerogel material in Example 5 has a larger average pore size and more developed pores, resulting in a faster permeation rate of crude phenolic oil and a shorter time required to reach saturation absorption. Furthermore, with increasing aerogel volume, the maximum absorption value of the sulfonated graphene aerogel prepared in this invention can reach 15 g.

[0072] The above results indicate that the volume of the sulfonated graphene aerogel prepared by this invention is adjustable, and its saturated absorption capacity for crude phenolic oil can reach 250-375 g / g. Furthermore, as the volume increases, the time for the dry aerogel to reach its maximum absorption capacity decreases, significantly increasing the amount of crude phenolic oil processed per unit time. Compared with multi-stage distillation, this invention is highly operable in practical applications, shortens the time in actual production processes, and saves some production costs.

[0073] Example 8: Determination of Adsorption Performance 1. Main materials The sulfonated graphene aerogel prepared in Example 3 (see Example 3) Figure 1 Commercial powder adsorbents: activated carbon, alumina, zeolite; crude phenolic oil containing trace amounts of amides, esters, and ethers, which are highly polar extractants.

[0074] 2. Main methods (1) The dried sulfonated graphene aerogel prepared in Example 3 was placed vertically into a beaker, and 5 g of crude phenol oil was dropped onto its surface. The beaker was then sealed with an organic membrane and placed in a dark environment at 50 °C for 30 min for adsorption treatment.

[0075] (2) Take the same volume (6 cm³) of aerogel as in Example 3. 3 Three commercial powder adsorbents were placed in short-tube funnels, and 5 g of crude phenol oil was dropped onto their surfaces. The funnels were then sealed with an organic membrane and placed in a dark environment at 50 °C for 30 min for adsorption treatment.

[0076] (3) Take out the aerogel from step (2) and put it into the empty tube of a specially made quartz syringe with a built-in stainless steel filter. Use the quartz pusher to squeeze the aerogel and collect the absorbed phenolic oil. Then collect the phenolic oil in the funnel from step (3). Use gas chromatography-mass spectrometry to quantitatively detect the content of phenolic compounds.

[0077] 3. Results Analysis from Figure 5As can be seen, the sulfonated aerogels prepared in Example 3 all achieved effective separation of amide, ester, and ether-based highly polar extractants: the content of phenolic compounds in crude phenolic oil containing amide extractants increased from 60 wt% to 89 wt%, with an adsorption rate of 72.5%; the content of phenolic compounds in crude phenolic oil containing ester extractants increased from 63 wt% to 93 wt%, with an adsorption rate of 75%; and the content of phenolic compounds in crude phenolic oil containing ether extractants increased from 61 wt% to 87 wt%, with an adsorption rate of 65%, indicating that the adsorption effect on ester extractants was superior. In contrast, the three commercial powder adsorbents—activated carbon, alumina, and zeolite—had poor adsorption effects on amide, ester, and ether-based highly polar extractants, with almost no change in the content of phenolic compounds in the crude phenolic oil before and after adsorption treatment. In contrast, the sulfonated aerogel prepared in this invention exhibits high efficiency and selectivity in the adsorption and separation of three strongly polar extractants. Although trace amounts of extractant remain in the treated crude phenolic oil, these are unmatched by commercial powder adsorbents. Furthermore, the crude phenolic oil collected after treatment in Example 3 was 4.4–4.6 g, with a recovery rate as high as 88–92%.

[0078] The above results indicate that the sulfonated graphene aerogel prepared in this invention can effectively improve the separation efficiency of highly polar extractants in crude phenol oil, achieving selective adsorption. Compared with commercial adsorbents, this invention has greater potential for large-scale application in actual production processes.

[0079] In summary, the experimental results show that compressible sulfonated graphene aerogel adsorbents have great potential for adsorption and separation of highly polar extractants in solvent extraction processes for phenol production.

[0080] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An application of a compressible sulfonated graphene aerogel adsorbent material, characterized in that: The aerogel adsorbent material is used for the separation of highly polar extractants in crude phenol oil; The preparation method of the aerogel adsorbent material includes the following steps: (1) Dissolve aminobenzenesulfonic acid powder in sodium hydroxide solution, then add nitrite and strong acid, and carry out diazotization reaction under ice bath stirring to generate aminobenzenesulfonic acid diazonium salt; The sodium hydroxide solution is at a temperature of 35-50°C, and the mass fraction of sodium hydroxide is 2-5%. The molar ratio of aminobenzenesulfonic acid to nitrite is 1:1 to 1.5, and the molar ratio of aminobenzenesulfonic acid to concentrated strong acid is 1:2.5 to 5. The diazotization reaction temperature is 0 ~ 10 ℃, and the diazotization reaction time is 15 ~ 25 min; (2) The obtained diazonium salt of aminobenzenesulfonic acid was added dropwise to a uniformly dispersed graphite oxide dispersion, and sulfonation was carried out under ice bath stirring to generate sulfonated graphite oxide dispersion. The concentration of the graphite oxide dispersion is 10-20 mg / mL, and the mass ratio of the graphite oxide dispersion to aminobenzenesulfonic acid is 1:1-6. The sulfonation treatment temperature is 0 ~ 10 ℃, and the sulfonation treatment time is 2 ~ 6 h; (3) The obtained sulfonated graphite oxide dispersion was centrifuged and washed, and then prepared into a uniform dispersion and stored at low temperature. The concentration of the sulfonated graphite oxide dispersion was 2-5 mg / mL, and the storage temperature was 0-8 ℃. (4) After mixing the prepared sulfonated graphene oxide dispersion with anhydrous ethylenediamine, a hydrothermal reaction is carried out to synthesize sulfonated graphene hydrogel. The volume ratio of the sulfonated graphite oxide dispersion to anhydrous ethylenediamine is 500:1~5, and the stirring time is 10~20 min; the hydrothermal reaction temperature is 120~200 ℃, and the hydrothermal reaction time is 10~15 h; (5) The obtained sulfonated graphene hydrogel was purified by soaking in deionized water and then freeze-dried to obtain a compressible sulfonated graphene aerogel adsorbent material. The freeze-drying process involves freezing the food and then transferring it to a freeze dryer at -50 to -70°C for 36 to 96 hours.

2. The application of the compressible sulfonated graphene aerogel adsorbent material according to claim 1, characterized in that: The aminobenzenesulfonic acid is one of o-aminobenzenesulfonic acid, m-aminobenzenesulfonic acid, and p-aminobenzenesulfonic acid.

3. The application of the compressible sulfonated graphene aerogel adsorbent material according to claim 1, characterized in that: The nitrite is either sodium nitrite or potassium nitrite.

4. The application of the compressible sulfonated graphene aerogel adsorbent material according to claim 1, characterized in that: The strong acid is one of hydrochloric acid, hydrobromic acid, tetrafluoroboric acid, perchloric acid, trifluoroacetic acid, and methanesulfonic acid.

5. The application of the compressible sulfonated graphene aerogel adsorbent material according to claim 1, characterized in that: The dispersant for the sulfonated graphite oxide dispersion is one of ultrapure water, deionized water, dimethylformamide, N-methylpyrrolidone, and ethylene glycol.

6. The application of the compressible sulfonated graphene aerogel adsorbent material according to claim 1, characterized in that, The centrifugal washing step of the sulfonated graphite oxide dispersion in step (3) includes: a. Centrifuge the sulfonated graphite oxide dispersion obtained from the reaction at a speed of 8000 ~ 9000 r / min for 10 ~ 15 min, separate the supernatant and retain the lower brown precipitate; b. Add deionized water to the top layer of the precipitate and mix evenly. Centrifuge at 7000-8000 r / min for 5-10 min, separate the supernatant and retain the lower brown precipitate. c. Repeat step b until the pH of the supernatant is 5-6.

7. The application of the compressible sulfonated graphene aerogel adsorbent material according to claim 1, characterized in that: The highly polar extractant is a highly polar extractant containing amides, esters, or ethers.

8. The application of the compressible sulfonated graphene aerogel adsorbent material according to claim 1, characterized in that, The separation process is as follows: (1) Add crude phenolic oil treated by solvent extraction to a beaker and record the total mass as M0; place the dried sulfonated graphene aerogel material in it and remove it every 2-5 minutes, and record the remaining total mass as M. n Calculate the cumulative absorbed mass ΔM of crude phenolic oil. n , where: △M n =M0-M n ; until △M n Approaching stability; with absorption time as the x-axis and cumulative absorbed mass ΔM n Plotting the absorption equilibrium curve on the ordinate, we obtain the maximum absorption value M for this volume of aerogel. max ; (2) Place the same dry aerogel as in step (1) vertically into the beaker, and then drop a mass of M onto its surface. max The crude phenolic oil was then sealed in a beaker with an organic membrane and placed in a dark environment at 40-60°C for 20-40 minutes for adsorption treatment. (3) Take out the aerogel from step (2) and put it into the empty tube of a special quartz syringe with a built-in stainless steel filter. Use the quartz push rod to squeeze the aerogel and collect the absorbed phenolic oil. Then use gas chromatography-mass spectrometry to quantitatively detect the content of phenolic compounds.

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