Hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disrupters as well as preparation method and application of hydrothermal carbon-based composite material
By combining rice husk hydrothermal carbon with mesoporous silica foam and loading it with polyethyleneimine, the problems of small specific surface area and imperfect pore structure of hydrothermal carbon were solved, achieving efficient adsorption of bisphenol A and maintaining stability during high-temperature regeneration, which is in line with the principles of green chemistry.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-18
- Publication Date
- 2026-03-13
AI Technical Summary
Existing hydrothermal carbon has a limited specific surface area and an imperfect pore structure, resulting in insufficient adsorption capacity and mass transfer rate. Furthermore, polyethyleneimine is prone to deactivation through urea reaction during thermal regeneration.
Rice husk hydrothermal carbon and mesoporous silica foam are mixed in a certain proportion to form a composite carrier, and polyethyleneimine is loaded onto it. The three-dimensional interconnected channels and surface silanol groups of the mesoporous silica foam stabilize the polyethyleneimine and inhibit its urea reaction during high-temperature regeneration. At the same time, boron and phosphorus elements are introduced to enhance the diversity of surface functional groups.
It significantly improves the adsorption capacity and selectivity for bisphenol A, with an adsorption capacity retention rate of over 90%, achieving efficient regeneration and recycling of the material, which is in line with the principles of green chemistry.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of bisphenol A adsorption technology, and in particular to a hydrothermal carbon-based composite material for adsorbing bisphenol A-type endocrine disruptors, its preparation method and application. Background Technology
[0002] Bisphenol A (BPA) is a typical endocrine disruptor widely used in the production of polycarbonate plastics and epoxy resins. Even at extremely low concentrations (ng / L-μg / L) in the environment, it can pose potential harm to organisms and ecosystems. Adsorption is considered a promising technology due to its simplicity and relatively low cost. Activated carbon is a commonly used adsorbent, but its selectivity for trace amounts of lipophilic organic pollutants is low, and regeneration is difficult. Hydrothermal carbon, a carbon-rich material prepared from biomass through a hydrothermal process, contains abundant oxygen-containing functional groups (such as carboxyl and hydroxyl groups), exhibiting good affinity for certain organic pollutants, and its raw materials are widely available and inexpensive. However, the specific surface area of hydrothermal carbon is usually limited, and its pore structure is not fully developed, restricting its adsorption capacity and mass transfer rate. More importantly, when used directly as a carrier for polyethyleneimine (PEI), PEI is prone to ureaization during thermal regeneration, leading to rapid deactivation of the adsorbent.
[0003] Therefore, in view of the above problems, the present invention urgently needs to provide a hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors, its preparation method and application. Summary of the Invention
[0004] The purpose of this invention is to provide a hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors, its preparation method, and its application. The proposed method for preparing the hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors solves the problem that the specific surface area of single hydrothermal carbon is usually limited and the pore structure is not well developed, which restricts its adsorption capacity and mass transfer rate in the prior art.
[0005] The present invention provides a method for preparing a hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors, comprising the following steps:
[0006] Rice husk hydrothermal carbon and mesoporous silica foam were mixed at a mass ratio of 1:(1-5) to obtain a composite carrier;
[0007] Polyethyleneimine is dissolved in a solvent and stirred until homogeneous to obtain an impregnation solution. The composite carrier is then impregnated in the impregnation solution, stirred, and the solvent is evaporated to obtain a composite adsorbent. The mass ratio of the composite carrier to polyethyleneimine is 1:(0.4-0.6).
[0008] Preferably, the mesoporous silica foam has a specific surface area of not less than 800 m² / g and a pore volume of not less than 2.5 cm³ / g.
[0009] Preferably, the mesoporous silica foam preparation steps are as follows:
[0010] Using poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (PEO-PPO-PEO) as a template agent, 1,3,5-trimethylbenzene as a pore expander, and tetraethyl orthosilicate as a silicon source, hydrolysis and polycondensation were carried out under acidic conditions. After aging at 40-60℃ for 24 hours, hydrothermal crystallization was performed at 100-120℃, followed by washing, drying, and calcination at 500-600℃ for 4-6 hours to obtain mesoporous silica foam with a three-dimensional interconnected pore structure.
[0011] Preferably, the steps for preparing hydrothermal char from rice husks include:
[0012] Rice husks are washed, dried, and crushed to obtain rice husk granules;
[0013] Rice husk particles are mixed with boron and phosphorus-containing acid solution at a solid-liquid mass ratio of 1:(5-15) and soaked for 2-8 hours. After soaking, deionized water is added, and a hydrothermal reaction is carried out at 180-220℃. After the reaction is completed for 6-12 hours, the mixture is cooled, washed, and dried to obtain rice husk hydrothermal carbon rich in functional groups and with a loose structure.
[0014] Preferably, the acid solution includes hydrochloric acid, boric acid, and phosphoric acid, with a mass ratio of 1:1:1 and an acid concentration of 0.1-1.0 M.
[0015] Preferably, the calcination conditions for mesoporous silica foam are: heating to 550°C at a rate of 2°C / min and holding for 5 hours in an air atmosphere.
[0016] Preferably, the molecular weight of polyethyleneimine is 600-10000 Da.
[0017] Preferably, the solvent is methanol.
[0018] The present invention also provides a hydrothermal carbon-based composite material obtained based on the hydrothermal carbon-based composite material preparation method for adsorbing bisphenol A endocrine disruptors as described above.
[0019] The present invention also provides an application of the hydrothermal carbon-based composite material as described above in the adsorption of bisphenol A. The pH of the wastewater is adjusted to 5-9, the hydrothermal carbon-based composite material is added, and after adsorption, the hydrothermal carbon-based composite material is recovered. Bisphenol A is then recovered by elution with an organic solvent.
[0020] The hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors provided by this invention, its preparation method, and its application have the following advantages compared with the prior art:
[0021] 1. This invention proposes a method for preparing a hydrothermal carbon-based composite material for adsorbing bisphenol A-type endocrine disruptors. Mesoporous silica foam is a novel porous material with three-dimensional interconnected channels, ultra-high pore volume, and a large specific surface area. Its unique foam-like structure facilitates mass transport, making it an ideal adsorbent carrier. Combining it with hydrothermal carbon integrates the advantages of both. Hydrothermal carbon provides adsorption sites and surface activity, while mesoporous silica provides a large loading space and excellent mass transfer channels. Furthermore, its abundant silanol groups (Si-OH) can form hydrogen bonds or weak electrostatic interactions with the amino groups of polyethyleneimine. This interaction helps stabilize polyethyleneimine molecules and disperse their aggregation, thereby inhibiting the formation of urea bonds through intermolecular condensation during high-temperature regeneration. Polyethyleneimine is a high-molecular polymer rich in amino groups, which can strongly adsorb organic compounds containing benzene rings (such as bisphenol A) through hydrogen bonding, π-π stacking, and other interactions. Loading polyethyleneimine onto a hydrothermal carbon@MSF composite carrier can significantly improve the material's adsorption capacity and selectivity for bisphenol A.
[0022] 2. The method for preparing hydrothermal carbon-based composite materials for adsorbing bisphenol A endocrine disruptors provided by the present invention allows for the introduction of appropriate amounts of compounds containing elements such as boron and phosphorus into the acid solution to achieve element doping in the subsequent hydrothermal carbonization, enhance the diversity of surface functional groups, and inhibit the intermolecular condensation of polyethyleneimine during high-temperature regeneration, thereby improving the adsorption rate.
[0023] 3. The method for preparing hydrothermal carbon-based composite materials for adsorbing bisphenol A endocrine disruptors provided by the present invention optimizes the preparation method of mesoporous silica, achieving a surface area of 800-1000 m² / g and a pore volume of 2.5-3.0 cm³ / g. This ultra-large spatial structure not only efficiently accommodates and fixes hydrothermal carbon particles, preventing their stacking, but also provides an ideal environment for the uniform and high loading distribution of polyethyleneimine, greatly reducing the local concentration of polyethyleneimine molecules and physically reducing the probability of urea reaction.
[0024] 4. The method for preparing hydrothermal carbon-based composite materials for adsorbing bisphenol A endocrine disruptors provided by the present invention introduces mesoporous silica carrier. Through its huge specific surface area to disperse polyethyleneimine and the stabilizing effect of surface silanol groups, it effectively inhibits the urea reaction of polyethyleneimine during high-temperature regeneration. The hydrothermal carbon-based composite material obtained by the present invention retains more than 90% of its adsorption capacity after 10 cycles, while the retention rate of polyethyleneimine@hydrothermal carbon adsorbent with hydrothermal carbon as the carrier is less than 70%.
[0025] 5. The hydrothermal carbon-based composite material preparation method for adsorbing bisphenol A endocrine disruptors provided by the present invention allows the obtained adsorbent to be regenerated by mild solvent elution, and the bisphenol A in the eluent can be concentrated and recovered, realizing the transformation from "removal" to "recovery", which is in line with the principles of green chemistry. Detailed Implementation
[0026] The technical solution of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0027] The present invention provides a method for preparing a hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors, comprising the following steps:
[0028] S101) Rice husk hydrothermal carbon and mesoporous silica foam are mixed at a mass ratio of 1:(1-5) to obtain a composite carrier;
[0029] S102) Polyethyleneimine is dissolved in a solvent and stirred evenly to obtain an impregnation solution. The composite carrier is impregnated in the impregnation solution, stirred, and the solvent is evaporated to obtain a composite adsorbent. The mass ratio of the composite carrier to polyethyleneimine is 1:(0.4-0.6).
[0030] Specifically, the mesoporous silica foam has a specific surface area of not less than 800 m² / g and a pore volume of not less than 2.5 cm³ / g.
[0031] Specifically, the steps for preparing mesoporous silica foam are as follows:
[0032] Using poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (PEO-PPO-PEO) as a template agent, 1,3,5-trimethylbenzene as a pore expander, and tetraethyl orthosilicate as a silicon source, hydrolysis and polycondensation were carried out under acidic conditions. After aging at 40-60℃ for 24 hours, hydrothermal crystallization was performed at 100-120℃, followed by washing, drying, and calcination at 500-600℃ for 4-6 hours to obtain mesoporous silica foam with a three-dimensional interconnected pore structure.
[0033] Specifically, the steps for preparing hydrothermal char from rice husks include:
[0034] Rice husks are washed, dried, and crushed to obtain rice husk granules;
[0035] Rice husk particles are mixed with boron and phosphorus-containing acid solution at a solid-liquid mass ratio of 1:(5-15) and soaked for 2-8 hours. After soaking, deionized water is added, and a hydrothermal reaction is carried out at 180-220℃. After the reaction is completed for 6-12 hours, the mixture is cooled, washed, and dried to obtain rice husk hydrothermal carbon rich in functional groups and with a loose structure.
[0036] Specifically, the acid solution includes hydrochloric acid, boric acid, and phosphoric acid, with a mass ratio of 1:1:1 and an acid concentration of 0.1-1.0 M.
[0037] Specifically, the calcination conditions for mesoporous silica foam are as follows: in an air atmosphere, the temperature is increased to 550°C at a rate of 2°C / min and held for 5 hours.
[0038] Specifically, the molecular weight of polyethyleneimine is 600-10000 Da.
[0039] Specifically, the solvent is methanol.
[0040] The present invention also provides a hydrothermal carbon-based composite material obtained based on the hydrothermal carbon-based composite material preparation method for adsorbing bisphenol A endocrine disruptors as described above.
[0041] The present invention also provides an application of the hydrothermal carbon-based composite material as described above in the adsorption of bisphenol A. The pH of the wastewater is adjusted to 5-9, the hydrothermal carbon-based composite material is added, and after adsorption, the hydrothermal carbon-based composite material is recovered. Bisphenol A is then recovered by elution with an organic solvent.
[0042] This invention proposes a method for preparing a hydrothermal carbon-based composite material for adsorbing bisphenol A-type endocrine disruptors. Mesoporous silica foam is a novel porous material with three-dimensional interconnected channels, ultra-high pore volume, and a large specific surface area. Its unique foam-like structure facilitates mass transport, making it an ideal adsorbent carrier. Combining it with hydrothermal carbon integrates the advantages of both. Hydrothermal carbon provides adsorption sites and surface activity, while mesoporous silica provides a large loading space and excellent mass transfer channels. Furthermore, its abundant silanol groups (Si-OH) can form hydrogen bonds or weak electrostatic interactions with the amino groups of polyethyleneimine. This interaction helps stabilize polyethyleneimine molecules and disperse their aggregation, thereby inhibiting, to some extent, the formation of urea bonds through intermolecular condensation during high-temperature regeneration. Polyethyleneimine is a high-molecular polymer rich in amino groups, which can strongly adsorb organic compounds containing benzene rings (such as bisphenol A) through hydrogen bonding, π-π stacking, and other interactions. Loading polyethyleneimine onto a hydrothermal carbon@MSF composite carrier can significantly improve the material's adsorption capacity and selectivity for bisphenol A.
[0043] The present invention provides a method for preparing hydrothermal carbon-based composite materials for adsorbing bisphenol A endocrine disruptors. In this method, compounds containing elements such as boron and phosphorus can be introduced into the acid solution in appropriate amounts to achieve element doping in the subsequent hydrothermal carbonization, enhance the diversity of surface functional groups, and inhibit the intermolecular condensation of polyethyleneimine during high-temperature regeneration, thereby improving the adsorption rate.
[0044] The present invention provides a method for preparing hydrothermal carbon-based composite materials for adsorbing bisphenol A endocrine disruptors. By optimizing the preparation method of mesoporous silica, the surface area can reach 800-1000 m² / g and the pore volume can reach 2.5-3.0 cm³ / g. This ultra-large spatial structure can not only efficiently accommodate and fix hydrothermal carbon particles and prevent them from stacking, but also provide an ideal environment for the uniform and high loading distribution of polyethyleneimine, greatly reducing the local concentration of polyethyleneimine molecules and reducing the probability of urea reaction from a physical spatial perspective.
[0045] The present invention provides a method for preparing hydrothermal carbon-based composite materials for adsorbing bisphenol A endocrine disruptors. The introduction of mesoporous silica carrier effectively inhibits the urea reaction of polyethyleneimine during high-temperature regeneration by dispersing polyethyleneimine through its huge specific surface area and the stabilizing effect of surface silanol groups. The hydrothermal carbon-based composite material obtained by the present invention retains more than 90% of its adsorption capacity after 10 cycles, while the retention rate of polyethyleneimine@hydrothermal carbon adsorbent with hydrothermal carbon as the carrier is less than 70%.
[0046] The present invention provides a method for preparing hydrothermal carbon-based composite materials for adsorbing bisphenol A endocrine disruptors. The obtained adsorbent can be regenerated by mild solvent elution, and the bisphenol A in the eluent can be concentrated and recovered, realizing the transformation from "removal" to "recovery", which is in line with the principles of green chemistry.
[0047] Example 1
[0048] The specific method for preparing a hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors is as follows:
[0049] 101) Rice husk hydrothermal carbon and mesoporous silica foam were mixed at a mass ratio of 1:1 to obtain a composite carrier;
[0050] 102) Dissolve polyethyleneimine in a solvent, stir until homogeneous to obtain an impregnation solution, impregnate the composite carrier in the impregnation solution, stir, evaporate the solvent to obtain a composite adsorbent, wherein the mass ratio of the composite carrier to polyethyleneimine is 1:0.4.
[0051] The mesoporous silica foam of this embodiment has a specific surface area of not less than 800 m² / g and a pore volume of not less than 2.5 cm³ / g.
[0052] The mesoporous silica foam preparation steps in this embodiment are as follows:
[0053] Using poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (PEO-PPO-PEO) as a template agent, 1,3,5-trimethylbenzene as a pore expander, and tetraethyl orthosilicate as a silicon source, hydrolysis and polycondensation were carried out under acidic conditions. After aging at 40°C for 24 hours, hydrothermal crystallization was performed at 100°C. The foam was then washed, dried, and calcined at 500°C for 4 hours to obtain mesoporous silica foam with a three-dimensional interconnected pore structure.
[0054] The steps for preparing hydrothermal char from rice husks in this embodiment include:
[0055] Rice husks are washed, dried, and crushed to obtain rice husk granules;
[0056] Rice husk particles were mixed with boron and phosphorus-containing acid solution at a solid-liquid mass ratio of 1:5 and soaked for 2 hours. After soaking, deionized water was added, and a hydrothermal reaction was carried out at 180°C. After 6 hours of reaction, the mixture was cooled, washed, and dried to obtain rice husk hydrothermal carbon rich in functional groups and with a loose structure.
[0057] The acid solution in this embodiment includes hydrochloric acid, boric acid, and phosphoric acid, with a mass ratio of 1:1:1 and an acid concentration of 0.4M.
[0058] The calcination conditions for the mesoporous silica foam in this embodiment are as follows: under an air atmosphere, the temperature is increased to 550°C at a rate of 2°C / min and maintained for 5 hours.
[0059] The molecular weight of the polyethyleneimine in this embodiment is 600 Da.
[0060] The solvent in this embodiment is methanol.
[0061] This invention also provides a hydrothermal carbon-based composite material that can be used to adsorb bisphenol A. Specifically, the pH of the wastewater is adjusted to 9, the hydrothermal carbon-based composite material is added, and after adsorption, the hydrothermal carbon-based composite material is recovered. Bisphenol A is then recovered by elution with an organic solvent.
[0062] The adsorption properties of the obtained hydrothermal carbon-based composite material are shown in Table 1.
[0063] Example 2
[0064] The specific method for preparing a hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors is as follows:
[0065] 201) Rice husk hydrothermal carbon and mesoporous silica foam were mixed at a mass ratio of 1:5 to obtain a composite carrier;
[0066] 202) Dissolve polyethyleneimine in a solvent, stir until homogeneous to obtain an impregnation solution, impregnate the composite carrier in the impregnation solution, stir, evaporate the solvent to obtain a composite adsorbent, wherein the mass ratio of the composite carrier to polyethyleneimine is 1:0.6.
[0067] The mesoporous silica foam of this embodiment has a specific surface area of not less than 800 m² / g and a pore volume of not less than 2.5 cm³ / g.
[0068] The mesoporous silica foam preparation steps in this embodiment are as follows:
[0069] Using poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (PEO-PPO-PEO) as a template agent, 1,3,5-trimethylbenzene as a pore expander, and tetraethyl orthosilicate as a silicon source, hydrolysis and polycondensation were carried out under acidic conditions. After aging at 60°C for 24 hours, hydrothermal crystallization was performed at 120°C. The foam was then washed, dried, and calcined at 600°C for 6 hours to obtain mesoporous silica foam with a three-dimensional interconnected pore structure.
[0070] The steps for preparing hydrothermal char from rice husks in this embodiment include:
[0071] Rice husks are washed, dried, and crushed to obtain rice husk granules;
[0072] Rice husk particles were mixed with boron and phosphorus-containing acid solution at a solid-liquid mass ratio of 1:15 and soaked for 8 hours. After soaking, deionized water was added, and a hydrothermal reaction was carried out at 220℃. After reacting for 12 hours, the mixture was cooled, washed, and dried to obtain rice husk hydrothermal carbon rich in functional groups and with a loose structure.
[0073] The acid solution in this embodiment includes hydrochloric acid, boric acid, and phosphoric acid, with a mass ratio of 1:1:1 and an acid concentration of 0.1M.
[0074] The calcination conditions for the mesoporous silica foam in this embodiment are as follows: under an air atmosphere, the temperature is increased to 550°C at a rate of 2°C / min and maintained for 5 hours.
[0075] The molecular weight of the polyethyleneimine in this embodiment is 10,000 Da.
[0076] The solvent in this embodiment is methanol.
[0077] This invention also provides the application of hydrothermal carbon-based composite material in the adsorption of bisphenol A. Specifically, the pH of wastewater is adjusted to 9, hydrothermal carbon-based composite material is added, and after adsorption, the hydrothermal carbon-based composite material is recovered. Bisphenol A is then recovered by elution with an organic solvent.
[0078] The adsorption properties of the obtained hydrothermal carbon-based composite material are shown in Table 1.
[0079] Example 3
[0080] The specific method for preparing a hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors is as follows:
[0081] 301) Rice husk hydrothermal carbon and mesoporous silica foam are mixed at a mass ratio of 1:3 to obtain a composite carrier;
[0082] 302) Dissolve polyethyleneimine in a solvent, stir until homogeneous to obtain an impregnation solution, impregnate the composite carrier in the impregnation solution, stir, evaporate the solvent to obtain a composite adsorbent, wherein the mass ratio of the composite carrier to polyethyleneimine is 1:0.5.
[0083] The mesoporous silica foam of this embodiment has a specific surface area of not less than 800 m² / g and a pore volume of not less than 2.5 cm³ / g.
[0084] The mesoporous silica foam preparation steps in this embodiment are as follows:
[0085] Using poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (PEO-PPO-PEO) as a template agent, 1,3,5-trimethylbenzene as a pore expander, and tetraethyl orthosilicate as a silicon source, hydrolysis and polycondensation were carried out under acidic conditions. After aging at 50°C for 24 hours, hydrothermal crystallization was performed at 110°C. The foam was then washed, dried, and calcined at 550°C for 5 hours to obtain mesoporous silica foam with a three-dimensional interconnected pore structure.
[0086] The steps for preparing hydrothermal char from rice husks in this embodiment include:
[0087] Rice husks are washed, dried, and crushed to obtain rice husk granules;
[0088] Rice husk particles were mixed with boron and phosphorus-containing acid solution at a solid-liquid mass ratio of 1:10 and soaked for 5 hours. After soaking, deionized water was added, and a hydrothermal reaction was carried out at 200℃. After reacting for 10 hours, the mixture was cooled, washed, and dried to obtain rice husk hydrothermal carbon rich in functional groups and with a loose structure.
[0089] The acid solution in this embodiment includes hydrochloric acid, boric acid, and phosphoric acid, with a mass ratio of 1:1:1 and an acid concentration of 1.0 M.
[0090] The calcination conditions for the mesoporous silica foam in this embodiment are as follows: under an air atmosphere, the temperature is increased to 550°C at a rate of 2°C / min and maintained for 5 hours.
[0091] The molecular weight of the polyethyleneimine in this embodiment is 8000 Da.
[0092] The solvent in this embodiment is methanol.
[0093] In this embodiment, the hydrothermal carbon-based composite material is used to adsorb bisphenol A. Specifically, the pH of the wastewater is adjusted to 5, the hydrothermal carbon-based composite material is added, and after adsorption, the hydrothermal carbon-based composite material is recovered. Bisphenol A is then recovered by elution with an organic solvent.
[0094] The adsorption properties of the obtained hydrothermal carbon-based composite material are shown in Table 1.
[0095] Comparative Example 1
[0096] The only difference between this comparative example and Example 1 is that hydrothermal carbon was not added. The performance of the obtained adsorbent is shown in Table 1.
[0097] Compared to Example 1, the comparative example, due to the absence of hydrothermal carbon, showed a significant decrease in the saturated adsorption capacity of the adsorbent for bisphenol A, and the adsorption capacity retention rate after 10 adsorption-desorption cycles was significantly lower than that of Example 1. This is because the surface of the hydrothermal carbon is rich in various oxygen-containing functional groups (such as carboxyl and hydroxyl groups). These functional groups can not only directly adsorb bisphenol A molecules through non-covalent interactions such as hydrogen bonding and π-π stacking, but also enhance the overall hydrophilicity and surface activity of the composite material, thereby increasing its affinity for bisphenol A. Furthermore, the introduction of hydrothermal carbon helps disperse the interfacial interactions between mesoporous silica foam (MSF) and polyethyleneimine (PEI), optimizing the spatial distribution of PEI and preventing its local aggregation, thus improving the availability of adsorption sites. During regeneration, the stable carbon skeleton structure of the hydrothermal carbon can buffer thermal stress to a certain extent, protecting PEI molecules from excessive thermal degradation, thus resulting in higher cycle stability.
[0098] Comparative Example 2
[0099] The only difference between this comparative example and Example 1 is that mesoporous silica was not added. The performance of the obtained adsorbent is shown in Table 1.
[0100] Compared to Example 1, the comparative example showed a significant decrease in the saturated adsorption capacity of the adsorbent for bisphenol A due to the absence of mesoporous silica. This is because mesoporous silica foam (MSF) possesses an extremely high specific surface area (≥800 m² / g) and ultra-large pore volume (≥2.5 cm³ / g), and its three-dimensional interconnected pore structure provides ample loading space and excellent mass transfer channels for polyethyleneimine. The abundant silanol groups (Si–OH) on the MSF surface can form hydrogen bonds or weak electrostatic interactions with the amino groups of polyethyleneimine, effectively stabilizing the polyethyleneimine molecules and preventing intermolecular condensation to form urea bonds during heat treatment or regeneration, thereby maintaining adsorption activity. Furthermore, the introduction of mesoporous silica foam significantly enhances the pore structure and physical adsorption capacity of the composite material, which is beneficial for the diffusion and enrichment of bisphenol A molecules within the material.
[0101] Comparative Example 3
[0102] The only difference between this comparative example and Example 1 is that the mass ratio of the composite carrier to polyethyleneimine is 1:0.8. The performance of the obtained adsorbent is shown in Table 1.
[0103] Compared to Example 1, the polyethyleneimine loading in this comparative example exceeded that in Example 1, resulting in a significant decrease in the saturated adsorption capacity of the adsorbent for bisphenol A. This is because the composite support provides a large loading space and mass transfer channels. The abundant silanol groups (Si-OH) on its surface can form hydrogen bonds or weak electrostatic interactions with the amino groups of polyethyleneimine, which helps stabilize polyethyleneimine molecules and inhibit the formation of urea bonds through intermolecular condensation during high-temperature regeneration, thereby improving the regeneration stability of the adsorbent. However, excessive polyethyleneimine can lead to excessive accumulation and aggregation of polyethyleneimine molecules on the support surface and within the pores, blocking some pores and reducing the effective specific surface area and mass transfer efficiency of the composite material. At the same time, an excessively high polyethyleneimine loading can cause excessively high local amino group concentrations, which can increase the risk of intermolecular condensation, especially during high-temperature regeneration, making urea formation more likely to occur, leading to functional group loss and adsorption performance degradation. In addition, excessive polyethyleneimine may also affect the structural stability of the composite material, making it more susceptible to physical damage or activity reduction during recycling.
[0104] Comparative Example 4
[0105] The only difference between this comparative example and Example 1 is that the acid solution is hydrochloric acid. The performance of the obtained adsorbent is shown in Table 1.
[0106] Compared to Example 1, the acid used in this comparative example is hydrochloric acid. The saturated adsorption capacity of the obtained adsorbent for bisphenol A is significantly reduced. This is because the introduction of elements such as boron and phosphorus achieves element doping in the subsequent hydrothermal carbonization, enhances the diversity of surface functional groups, and inhibits the intermolecular condensation of polyethyleneimine molecules during high-temperature regeneration. This ensures that the saturated adsorption capacity for bisphenol A is maintained above 140 mg / g, while the adsorption capacity retention rate after 10 adsorption-desorption cycles is above 90%.
[0107] Table 1 Adsorption performance parameters of hydrothermal carbon-based composite materials
[0108]
[0109] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing a hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors, characterized in that: Includes the following steps: Rice husk hydrothermal carbon and mesoporous silica foam were mixed at a mass ratio of 1:(1-5) to obtain a composite carrier; Polyethyleneimine is dissolved in a solvent and stirred until homogeneous to obtain an impregnation solution. The composite carrier is then impregnated in the impregnation solution, stirred, and the solvent is evaporated to obtain a composite adsorbent. The mass ratio of the composite carrier to polyethyleneimine is 1:(0.4-0.6).
2. The method for preparing the hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors according to claim 1, characterized in that: The specific surface area of the mesoporous silica foam is not less than 800 m² / g, and the pore volume is not less than 2.5 cm³ / g.
3. The method for preparing the hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors according to claim 1, characterized in that: Mesoporous silica foam preparation steps: Using poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (PEO-PPO-PEO) as a template agent, 1,3,5-trimethylbenzene as a pore expander, and tetraethyl orthosilicate as a silicon source, hydrolysis and polycondensation were carried out under acidic conditions. After aging at 40-60℃ for 24 hours, hydrothermal crystallization was performed at 100-120℃, followed by washing, drying, and calcination at 500-600℃ for 4-6 hours to obtain mesoporous silica foam with a three-dimensional interconnected pore structure.
4. The method for preparing the hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors according to claim 1, characterized in that: The steps for preparing hydrothermal charcoal from rice husks include: Rice husks are washed, dried, and crushed to obtain rice husk granules; Rice husk particles are mixed with boron and phosphorus-containing acid solution at a solid-liquid mass ratio of 1:(5-15) and soaked for 2-8 hours. After soaking, deionized water is added, and a hydrothermal reaction is carried out at 180-220℃. After the reaction is completed for 6-12 hours, the mixture is cooled, washed, and dried to obtain rice husk hydrothermal carbon rich in functional groups and with a loose structure.
5. The method for preparing the hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors according to claim 1, characterized in that: The acid solution includes hydrochloric acid, boric acid, and phosphoric acid, with a mass ratio of 1:1:1 and a concentration of 0.1-1.0 M.
6. The method for preparing the hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors according to claim 1, characterized in that: The calcination conditions for mesoporous silica foam are as follows: in an air atmosphere, the temperature is increased to 550℃ at a rate of 2℃ / min and held for 5 hours.
7. The method for preparing the hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors according to claim 1, characterized in that: The molecular weight of polyethyleneimine is 600-10000 Da.
8. The method for preparing the hydrothermal carbon-based composite material for adsorbing bisphenol A endocrine disruptors according to claim 1, characterized in that: The solvent is methanol.
9. A hydrothermal carbon-based composite material obtained by the method for preparing hydrothermal carbon-based composite materials for adsorbing bisphenol A endocrine disruptors as described in any one of claims 1-8.
10. An application of the hydrothermal carbon-based composite material as described in claim 9 in the adsorption of bisphenol A, characterized in that: The pH of the wastewater was adjusted to 5-9, and a hydrothermal carbon-based composite material was added. After adsorption, the hydrothermal carbon-based composite material was recovered, and bisphenol A was recovered by elution with an organic solvent.