High-performance adsorption material for sewage treatment and preparation method thereof

Abstract

The invention discloses a high-performance adsorption material for sewage treatment and a preparation method thereof, and relates to the technical field of sewage treatment. The high-performance adsorption material for sewage treatment is prepared from an enhanced tannin grafted deacetylated konjac glucomannan ternary composite adsorption material, a polyacrylic acid grafted amino modified silicon dioxide aerogel material and genipin, an enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorption material and a polyacrylic acid-grafted amino-modified silica aerogel material form a stable and uniform three-dimensional integral network with highly interconnected inside under the crosslinking action, and the three-dimensional integral network is rich in three powerful functional groups, namely carboxyl, amino and phenolic hydroxyl, so that the adsorption capacity of the adsorption material is improved; according to the present invention, the ultra-high capacity adsorption and the ultra-wide pH range adaptability to the heavy metal ions are achieved through the broad-spectrum and efficient chelation and ion exchange action mode, the adsorption performance is significantly enhanced, and the sewage purification treatment effect is optimized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of sewage treatment, and particularly relates to a high-performance adsorption material for sewage treatment and a preparation method thereof. BACKGROUND

[0002] Water resources are the basis for human survival and development. With the continuous development of industry and agriculture, the problem of heavy metal water pollution is becoming more and more serious. Among them, copper and lead are two heavy metals widely used in industrial production. Copper is used for metal polishing, electroplating, etching and production of electronic products. Lead is used for processing of lead-acid batteries and paints. High concentrations of copper and lead in industrial wastewater are non-biodegradable, toxic and easily accumulated in the body, causing serious harm to human health. They can also accumulate through the food chain and have a great impact on human health and the ecosystem. Therefore, water heavy metal pollution has attracted great attention worldwide. In recent years, among various technologies that can be used to remove heavy metal pollutants, the research on heavy metal ion adsorption materials is particularly active. It is of great significance to prepare adsorption materials with excellent adsorption capacity and stability for their application.

[0003] The existing technology mainly has the following problems:

[0004] The adsorption capacity of conventional adsorption materials is low, and the applicable pH range is too narrow, which limits the play of adsorption performance, and is not conducive to the purification and adsorption effect of sewage. SUMMARY

[0005] In view of the above situation, in order to overcome the defects of the prior art, the application provides a high-performance adsorption material for sewage treatment, which comprises the following components in parts by weight: 20-40 parts of enhanced tannin grafted deacetylated konjac glucomannan ternary composite adsorption material, 10-20 parts of polyacrylic acid grafted amino modified silica aerogel material and 3-5 parts of genipin.

[0006] The enhanced tannin grafted deacetylated konjac glucomannan ternary composite adsorption material comprises the following components in parts by weight: 70-85 parts of deacetylated konjac glucomannan, 10-15 parts of nano cellulose, 8-10 parts of chitosan and 20-30 parts of tannin.

[0007] The preparation method of the enhanced tannin grafted deacetylated konjac glucomannan ternary composite adsorption material specifically comprises the following steps:

[0008] (1) Disperse konjac glucomannan in 500 mL of 40% ethanol solution, stir and heat to 40-50℃, then add 8.0-10.0 g of anhydrous sodium carbonate and continue stirring for 1-2 h. Cool at room temperature, filter, transfer the solid product to a beaker, add 100 mL of distilled water to disperse, and add 0.1 mol / L hydrochloric acid standard solution dropwise while stirring to neutralize until the pH of the suspension is 6.5-7.5. Filter, wash the precipitate 3-5 times with 30% ethanol solution, and finally wash 3-5 times with distilled water. Vacuum dry at 100℃. The acetyl groups on the side chains of konjac glucomannan molecules are partially or completely removed, directly exposing the acetyl groups. The presence of more active hydroxyl groups enhances the hydrophilicity and reactivity of the molecule. The increased intramolecular and intermolecular hydrogen bonding after deacetylation makes it easier to form an ordered and stable three-dimensional network gel structure in water. The micropores and channels in the gel network provide pathways for the diffusion of heavy metal ions into the interior of the material, allowing the active sites inside to participate in adsorption, thereby improving the adsorption capacity. Furthermore, under acidic conditions, the gel network of deacetylated konjac glucomannan can still maintain its basic structure and remain insoluble, providing a stable working platform for other components. Under alkaline conditions, it can assist in the adsorption of metal cations through electrostatic attraction, thereby broadening the applicable pH range and obtaining deacetylated konjac glucomannan.

[0009] (2) Add the dried nanocellulose to 50mL of distilled water, stir magnetically for 10-20min, then sonicate in an ice bath for 10-20min. The sonication power is 250-300W, and the sonication time is 2s with a 1s interval to form a nanocellulose dispersion for later use. Weigh 0.8-1.0g of chitosan powder with a deacetylation degree ≥90% and add it to 100mL of 1% acetic acid aqueous solution. Stir in a water bath at 40-50℃ for 1-2h to form a chitosan acetic acid solution for later use. Then add 200mL of distilled water to a three-necked flask. While stirring at 200-250rpm, first add the nanocellulose dispersion, keeping the stirring speed constant, and then slowly add it at a rate of 1-2 drops / second using a constant pressure dropping funnel. Slowly add the chitosan-acetic acid solution, and continue stirring for 30-40 minutes after the addition is complete. Then add the deacetylated konjac glucomannan described in step (1), and add distilled water to ensure the reaction system reaches 300 mL. Stir at room temperature for 1-2 hours. With deacetylated konjac glucomannan as the main body of the three-dimensional network and nanocellulose as the reinforcing skeleton to improve the stability of the structure, chitosan is firmly fixed in the stable network formed by deacetylated konjac glucomannan and nanocellulose. A large number of amino groups on the chitosan molecular chain play an adsorption role as strong functional groups for binding heavy metals, and can maintain structural integrity over a wider pH range. At the same time, the deacetylated konjac glucomannan gel network in the composite substrate has hydrophilicity and weak buffering capacity, and can slightly consume H+. +To a certain extent, this protects the amino groups of chitosan and slows down its protonation, thereby broadening the effective lower limit of pH operation of the material to a stronger acidic environment, resulting in a composite substrate slurry.

[0010] (3) Add ascorbic acid and tannin to the composite base slurry described in step (2), stir at 200-250 rpm for 20-30 min under a nitrogen protective atmosphere, then add 30 mL of 3.4% hydrogen peroxide solution, react at 25℃ for 8-9 h, filter, and first soak and wash the solid with 100 mL of 0.4% sodium hydroxide solution 2-3 times, stirring for 5 min each time and then filtering. Then soak and wash with 100 mL of 1% sodium dodecyl sulfate aqueous solution at 50℃ 2-3 times, stirring for 10 min each time and then filtering. Finally wash with distilled water 3-5 times, and vacuum dry the solid product at 60℃. The tannin molecules undergo a free radical reaction initiated by ascorbic acid and hydrogen peroxide, and the hydrogen on the phenolic hydroxyl group is removed, forming Phenoxy radicals covalently couple with the active hydrogen sites on the molecular chains of deacetylated konjac glucomannan and chitosan, forming a stable complex with tannin molecules covalently bonded to the entire network via strong carbon-carbon or ether bonds. This complex is formed on the surface and inside of the nanocellulose-reinforced deacetylated konjac glucomannan / chitosan network. The entire framework surface is covered with a layer of hook-like active surface rich in catechol / triphenol structures, introducing a large number of highly active sites. It also possesses phenolic hydroxyl, amino, and hydroxyl functional groups, which greatly improves the adsorption capacity of heavy metals and significantly enhances the material's adaptability over a wide pH range, especially under strongly acidic conditions. This allows it to maintain excellent adsorption performance in different water environments, resulting in an enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material.

[0011] Preferably, in step (1), the amount of konjac glucomannan added is 8.0-10.0g. Konjac glucomannan swells in water to form a three-dimensional network framework, which provides a stable support and a huge dispersion and attachment space for subsequent grafting modification of substances. This is conducive to fully exposing various active adsorption sites and improving the site utilization rate. At the same time, under alkaline conditions, the hydroxyl groups on the konjac glucomannan molecular chain are partially deprotonated and become negatively charged, which can adsorb heavy metal cations through electrostatic interaction.

[0012] Preferably, in step (2), the amount of nanocellulose added is 1.0-1.5g. Nanocellulose can be interwoven into a nanoscale rigid network skeleton. Under extreme pH conditions, it can effectively prevent excessive swelling and collapse of chitosan and deacetylated konjac glucomannan, ensuring that the material can maintain its complete shape in a wide pH range. At the same time, the stable network skeleton prevents the gel from becoming dense, maximizing the maintenance and exposure of the pores and channels inside the material, providing a huge adhesion area for subsequent grafting, so that heavy metal ions can come into contact with the adsorption sites more fully, which is conducive to improving the overall adsorption capacity.

[0013] Preferably, in step (3), the amounts of ascorbic acid and tannin added are 0.5-1.0g and 2.0-3.0g, respectively. Tannin is rich in catechol / pyrogallol structure, and its phenolic hydroxyl group has a strong chelating ability for heavy metal ions such as copper and lead. One molecule of tannin can provide multiple coordination sites at the same time, and can form more stable chelates with metal ions with higher coordination ratios, thereby effectively improving the adsorption capacity. In addition, the phenolic hydroxyl group of tannin has a low degree of protonation, and its chelating effect is far less affected by acidity than that of amino groups. It becomes the main adsorption functional group under strong acid conditions, which greatly extends the effective working pH limit of the material. Under alkaline conditions, tannin still has a good chelating ability for metal hydroxyl complexes, further maintaining the adsorption performance of the material at higher pH.

[0014] This invention also provides a method for preparing a high-performance adsorbent material for wastewater treatment, specifically including the following steps:

[0015] S1. Add 25 mL of tetraethyl orthosilicate to 40 mL of anhydrous ethanol and stir until homogeneous. Adjust the pH to 3.0-4.0 with 0.1 mol / L hydrochloric acid standard solution. Stir magnetically at 50-60℃ for 1-2 h, cool to room temperature, and let stand for 2-4 h. The resulting gel will age at room temperature for 24 h. Then add anhydrous ethanol and continue aging in a 40℃ water bath for 24 h. Remove the wet gel and perform solvent exchange with anhydrous ethanol and n-hexane sequentially for 36-48 h, changing the solvent every 6 h. Freeze-dry the solvent-exchanged wet gel to obtain silica aerogel for later use. Add 3-aminopropyltriethoxysilane to 500 mL of anhydrous ethanol that has been dried with 3A molecular sieves and stir at room temperature for 10-15 min to form a modified solution for later use. Immerse the silica aerogel in the modified solution. Under nitrogen protection, the mixture was refluxed at 70-80℃ for 8-12 hours. After the reaction, the product was washed 3-5 times with anhydrous ethanol and finally vacuum dried at 60-80℃. The silanol groups after hydrolysis of 3-aminopropyltriethoxysilane condensed with the silanol groups on the surface of silica aerogel to form strong Si-O-Si covalent bonds, thereby chemically grafting its own aminopropyl groups onto the entire inner surface of the aerogel. This achieves high capacity and strong selectivity in capturing heavy metal ions. At the same time, it can also change its electrical properties under different pH conditions to achieve effective adsorption of various forms of heavy metals (cations and complexed anions). The stable covalent bond connection ensures that the amino functional groups will not leach out during use and regeneration, thus improving the stability and effectiveness of the adsorption performance of the aerogel material, resulting in amino-modified silica aerogel.

[0016] S2. Add MW5000 polyacrylic acid to 100 mL of MES buffer solution with pH 4.5-5.0, then add 0.3-0.5 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.1-0.2 g of N-hydroxysuccinimide. Stir for 20-30 min to form an activated polyacrylic acid solution. Immerse the amino-modified silica aerogel from step S1 into the activated polyacrylic acid solution. Adjust the pH to 7.5-8.0 within 1-2 min using a 0.4% pre-cooled sodium hydroxide solution. Then place the solution in a constant temperature water bath at 25-30℃ and stir for 12-24 h. Remove the aerogel and thoroughly soak and wash it with deionized water for 24-36 h, changing the water every 2 h. Deionized water was used until the washing liquid showed no chloride ions when tested with silver nitrate and no amino byproducts when tested with ninhydrin. Finally, the washed product was soaked and replaced with anhydrous ethanol and tert-butanol 2-3 times in sequence, 2 hours each time, and then freeze-dried. Polyacrylic acid long chains were grafted onto the surface of amino-modified silica aerogel. The synergistic cooperation of carboxyl and amino groups provided a large number of high-affinity adsorption sites, which significantly improved the adsorption capacity. The dissociation state of carboxyl groups on polyacrylic acid long chains at different pH values ​​perfectly complemented and relayed the protonated state of amino groups, so that at least one functional group was always in a highly efficient working state over a wide pH range, reducing the adverse effects of acid and alkaline environments on adsorption performance, and obtaining polyacrylic acid-grafted amino-modified silica aerogel material.

[0017] S3. Grind the polyacrylic acid-grafted amino-modified silica aerogel material described in step S2, controlling the particle size to 100-300 mesh, to obtain aerogel powder for later use. Grind the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material, controlling the particle size to 100-300 mesh, to obtain ternary composite powder for later use. Weigh 0.3-0.5g of genipin and add it to 200mL of PBS buffer (pH 8.0-9.0), and sonicate at 40℃ for 30-40min. Prepare a genipin crosslinking solution and set aside. Then, mix the aerogel powder and ternary composite powder and add them to 100 mL of deionized water. Sonicate the mixture in an ice bath for 20-30 min to form a suspension. Add the genipin crosslinking solution slowly to the suspension at a rate of 1-2 drops / second using a constant pressure dropping funnel, while stirring at 200-300 rpm. After the addition is complete, place the mixture in a 37°C water bath and stir at 200-250 rpm for 24-48 h. Filter the mixture. The filter cake was first repeatedly washed with deionized water until the washing liquid was colorless and clear. Then, it was soaked in ethanol solutions with mass fractions of 30%, 50%, 70%, and 90% for 4-6 hours each time. Finally, it was soaked in anhydrous ethanol and tert-butanol for 4-6 hours. The product was then removed and freeze-dried. It was first pre-frozen at -50℃ for 6-8 hours and then dried at -60℃ and a vacuum of 6-8 Pa for 48-72 hours. Using polyacrylic acid-grafted amino-modified silica aerogel as a rigid framework network and reinforced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent as flexible sites, the crosslinking agent anchored and intertwined the two to form a stable, uniform, and highly interconnected three-dimensional network. It also has three powerful functional groups: carboxyl, amino, and phenolic hydroxyl. Through broad-spectrum and efficient chelation and ion exchange, it achieved ultra-high capacity adsorption of heavy metal ions and ultra-wide pH range adaptability, further enhancing the purification and adsorption effect of wastewater, and obtaining a high-performance adsorbent material for wastewater treatment.

[0018] Preferably, in step S1, the amount of 3-aminopropyltriethoxysilane added is 18-24 mL. The amino group at the end of 3-aminopropyltriethoxysilane can form stable coordination bonds with heavy metal ions such as copper and lead, thereby increasing the chemical adsorption capacity. Furthermore, under acidic conditions, the amino group is highly protonated to -NH3. + It can adsorb metal complex anions through strong positive electrostatic adsorption, while under alkaline conditions, the amino group is completely deprotonated to -NH2, and still maintains a high adsorption capacity.

[0019] Preferably, in step S2, the amount of polyacrylic acid added is 0.8-1.0g. The carboxyl groups introduced by polyacrylic acid mainly adsorb heavy metal ions through ion exchange, and can work synergistically with amino sites to achieve broad-spectrum and efficient adsorption. Furthermore, under acidic conditions, although the carboxyl groups are partially protonated, there are still a large number of carboxyl groups on the long chain of polyacrylic acid that can undergo ion exchange. Under alkaline conditions, the carboxyl groups, as negatively charged groups, can assist in the electrostatic adsorption effect.

[0020] The beneficial effects achieved by this invention are as follows:

[0021] This invention utilizes a reinforced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material and a polyacrylic acid-grafted amino-modified silica aerogel material to form a stable, uniform, and highly interconnected three-dimensional network through cross-linking. This network is rich in three powerful functional groups: carboxyl, amino, and phenolic hydroxyl groups. Through broad-spectrum and efficient chelation and ion exchange, it achieves ultra-high capacity adsorption of heavy metal ions and adaptability to an ultra-wide pH range, significantly enhancing adsorption performance and optimizing wastewater treatment. In the reinforced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material, deacetylated konjac glucomannan serves as the main network component, nanocellulose acts as the reinforcing framework, and chitosan is... Immobilized within a stable network formed by deacetylated konjac glucomannan and nanocellulose, the numerous amino groups on the chitosan molecular chains act as powerful functional groups for binding heavy metals, exerting adsorption effects and maintaining structural integrity over a wider pH range. Tannin molecules are covalently bonded to the surface and interior of the nanocellulose-reinforced deacetylated konjac glucomannan / chitosan network, covering the entire framework surface with a layer of catechol / triphenol-rich hook-like active surfaces, introducing a large number of highly active sites. Simultaneously possessing phenolic hydroxyl, amino, and hydroxyl functional groups, these sites can synergistically enhance the adsorption capacity of heavy metals through multiple mechanisms such as coordination, ion exchange, and electrostatic attraction, and also greatly improve the material's adsorption capacity over a wider pH range. Its adaptability, especially under strongly acidic conditions, allows it to maintain excellent adsorption performance in various water environments. In the polyacrylic acid-grafted amino-modified silica aerogel material, the aminopropyl groups of 3-aminopropyltriethoxysilane are first chemically grafted onto the entire inner surface of the silica aerogel to complete the modification treatment. Then, long chains of polyacrylic acid are grafted onto the surface of the amino-modified silica aerogel. The introduced carboxyl and amino groups work synergistically as high-affinity adsorption sites, significantly improving the adsorption capacity. At the same time, the dissociation state of the carboxyl groups on the long chains of polyacrylic acid at different pH levels perfectly complements and reinforces the protonated state of the amino groups, making the material... Within a wide pH range, at least one functional group remains in a highly efficient working state, effectively broadening the pH applicability of the aerogel material. Furthermore, the flexible polymer chains swell in water, forming a hydrogel layer within the aerogel channels, expanding into an adsorbent with a three-dimensional structure, greatly increasing the contact volume of heavy metals and further enhancing adsorption capacity. This invention uses an enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material, polyacrylic acid-grafted amino-modified silica aerogel material, and genipin to create a high-performance adsorbent material for wastewater treatment. This material not only improves the adsorption capacity of heavy metals but also broadens the pH applicability range, achieving efficient and effective wastewater purification. Attached Figure Description

[0022] Figure 1The graphs show the adsorption results of Examples 1-4 and Comparative Examples 1-3 of this invention.

[0023] Figure 2 The graph shows the adsorption retention rate results of Examples 1-4 and Comparative Examples 1-3 of the present invention. Detailed Implementation

[0024] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0025] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those familiar to those skilled in the art. Furthermore, any methods and materials similar to or equivalent to those described herein may be applied to this invention. The preferred embodiments and materials described herein are for illustrative purposes only and do not limit the scope of this application.

[0026] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods; unless otherwise specified, the experimental materials used in the following embodiments are all purchased from commercial channels.

[0027] Example 1

[0028] This embodiment proposes a high-performance adsorbent material for wastewater treatment, comprising the following components in parts by weight: 40 parts of enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material, 20 parts of polyacrylic acid-grafted amino-modified silica aerogel material, and 5 parts of genipin.

[0029] The enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material comprises the following components in parts by weight: 85 parts deacetylated konjac glucomannan, 15 parts nanocellulose, 10 parts chitosan, and 30 parts tannin.

[0030] The preparation method of the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material specifically includes the following steps:

[0031] (1) Konjac glucomannan was dispersed in 500 mL of 40% ethanol solution. The amount of konjac glucomannan added was 10.0 g. Konjac glucomannan swelled in water to form a three-dimensional network framework, which provided a stable support and a large dispersion and attachment space for subsequent grafting modification of substances. This facilitated the full exposure of various active adsorption sites and improved the site utilization rate. At the same time, under alkaline conditions, the hydroxyl groups on the konjac glucomannan molecular chain were deprotonated and became negatively charged, which could adsorb heavy metal cations through electrostatic interaction. The mixture was stirred and heated to 50°C, and then 10.0 g of anhydrous sodium carbonate was added and stirred for 2 hours. After cooling at room temperature, the mixture was filtered, and the solid product was transferred to a beaker. 100 mL of distilled water was added to disperse the mixture. 0.1 mol / L hydrochloric acid standard solution was added dropwise under stirring to neutralize the mixture until the pH of the suspension was 7.5. The mixture was then filtered, and the precipitate was further treated with ethanol solution of 40% ethanol solution. Washed five times with 30% ethanol solution, and finally washed five times with distilled water, and then vacuum dried at 100℃, the acetyl groups on the side chains of konjac glucomannan molecules were partially or completely removed, directly exposing more active hydroxyl groups, thereby enhancing the hydrophilicity and reactivity of the molecules. The intramolecular and intermolecular hydrogen bonding after deacetylation is enhanced, making it easier to form an ordered and stable three-dimensional network gel structure in water. The micropores and channels in the gel network provide pathways for the diffusion of heavy metal ions into the interior of the material, allowing the internal active sites to participate in adsorption, which is beneficial to improving the adsorption capacity. Furthermore, under acidic conditions, the gel network of deacetylated konjac glucomannan can still maintain its basic structure and remain insoluble, providing a stable working platform for other components. Under alkaline conditions, it can assist the adsorption of metal cations through electrostatic attraction, thereby broadening the applicable pH range and obtaining deacetylated konjac glucomannan.

[0032] (2) Add 1.5g of dried nanocellulose to 50mL of distilled water. Nanocellulose can interweave into a nanoscale rigid network skeleton, which can effectively prevent excessive swelling and collapse of chitosan and deacetylated konjac glucomannan under extreme pH conditions, ensuring that the material can maintain its integrity over a wide pH range. At the same time, the stable network skeleton prevents the gel from densifying, maximizing the maintenance and exposure of the pores and channels inside the material, providing a huge adhesion area for subsequent grafting, so that heavy metal ions can come into full contact with the adsorption sites, thereby improving the overall adsorption capacity. First, stir magnetically for 20min, then sonicate in an ice bath for 20min. The sonication power is 300W, and the sonication time is 2s with a 1s interval to form a nanocellulose dispersion for later use. Weigh 1.0g of chitosan powder with a deacetylation degree ≥90% and add it to 100mL of 1% acetic acid aqueous solution. Stir in a 50℃ water bath for 2h to form a nanocellulose dispersion. Prepare a chitosan-acetic acid solution for later use. Then, add 200 mL of distilled water to a three-necked flask. While stirring at 250 rpm, first add the nanocellulose dispersion. Keep the stirring speed constant and slowly add the chitosan-acetic acid solution at a rate of 2 drops / second using a constant pressure dropping funnel. After the addition is complete, continue stirring for 40 min. Then, add the deacetylated konjac glucomannan described in step (1) and add distilled water to ensure that the reaction system reaches 300 mL. Stir at room temperature for 2 h. With deacetylated konjac glucomannan as the main body of the three-dimensional network and nanocellulose as the reinforcing skeleton to improve the stability of the structure, the chitosan is firmly fixed in the stable network formed by the deacetylated konjac glucomannan and nanocellulose. The large number of amino groups on the chitosan molecular chain play an adsorption role as a strong functional group for binding heavy metals and can maintain structural integrity over a wider pH range. At the same time, the deacetylated konjac glucomannan gel network in the composite substrate has hydrophilicity and weak buffering capacity, and can slightly consume H+. + To a certain extent, this protects the amino groups of chitosan and slows down its protonation, thereby broadening the effective lower limit of pH operation of the material to a stronger acidic environment, resulting in a composite substrate slurry.

[0033] (3) Add ascorbic acid and tannin to the composite substrate slurry described in step (2). The amounts of ascorbic acid and tannin added are 1.0g and 3.0g, respectively. Tannin is rich in catechol / pyrogallol structure. Its phenolic hydroxyl group has a strong chelating ability for heavy metal ions such as copper and lead. One molecule of tannin can provide multiple coordination sites at the same time, and can form more stable chelates with metal ions with higher coordination ratios, thereby effectively improving the adsorption capacity. In addition, the phenolic hydroxyl group of tannin has a low degree of protonation, and its chelating effect is far less affected by acidity than that of amino groups. It becomes a strong acidic adsorption medium under strong acid conditions. The main adsorption functional groups significantly extend the effective working pH limit of the material. Even under alkaline conditions, tannins maintain good chelating ability for metal hydroxyl complexes, further maintaining the material's adsorption performance at higher pH levels. Under a nitrogen atmosphere, the mixture was stirred at 250 rpm for 30 min, then 30 mL of 3.4% hydrogen peroxide solution was added, and the reaction was carried out at 25℃ for 9 h. After filtration, the solid was first soaked and washed three times with 100 mL of 0.4% sodium hydroxide solution, stirring for 5 min each time, followed by filtration. Then, it was treated with 10... The product was soaked and washed three times in a 1% sodium dodecyl sulfate aqueous solution at 50℃, with stirring for 10 min each time, followed by filtration. Finally, it was washed five times with distilled water. The solid product was then vacuum dried at 60℃. The tannin molecules underwent a free radical reaction initiated by ascorbic acid and hydrogen peroxide, resulting in the removal of hydrogen from the phenolic hydroxyl groups. The formed phenoxy radicals covalently coupled with the active hydrogen sites on the deacetylated konjac glucomannan and chitosan molecular chains, forming a strong carbon-carbon bond or ether bond chemically bonded to the entire network, thus creating a nanocellulose-reinforced deacetylated konjac glucomannan... The polysaccharide / chitosan network contains a stable complex of tannin molecules covalently bonded to its surface and interior. The entire framework surface is covered with a layer of hook-like active surfaces rich in catechol / triphenol structures, introducing a large number of highly active sites. It also possesses phenolic hydroxyl, amino, and hydroxyl functional groups, which greatly enhances the adsorption capacity of heavy metals and significantly improves the material's adaptability over a wide pH range, especially under strongly acidic conditions. This allows it to maintain excellent adsorption performance in different water environments, resulting in an enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material.

[0034] This embodiment provides a method for preparing a high-performance adsorption material for wastewater treatment, specifically including the following steps:

[0035] S1. Add 25 mL of tetraethyl orthosilicate to 40 mL of anhydrous ethanol and stir until homogeneous. Adjust the pH to 4.0 with 0.1 mol / L hydrochloric acid standard solution. Stir magnetically at 60 °C for 2 h, cool to room temperature, and let stand for 4 h. The resulting gel is aged at room temperature for 24 h. Then, add anhydrous ethanol and continue aging in a 40 °C water bath for 24 h. Remove the wet gel and perform solvent exchange with anhydrous ethanol and n-hexane sequentially for 48 h, changing the solvent every 6 h. Freeze-dry the solvent-exchanged wet gel to obtain silica aerogel for later use. Add 24 mL of 3-aminopropyltriethoxysilane to 500 mL of anhydrous ethanol that has been dried with 3A molecular sieves. The amino group at the end of 3-aminopropyltriethoxysilane can form stable coordination bonds with heavy metal ions such as copper and lead, improving the chemical adsorption capacity. Under acidic conditions, the amino group is highly protonated to -NH3. + It can adsorb metal complex anions through strong positive electrostatic adsorption. Under alkaline conditions, the amino group is completely deprotonated to -NH2, still maintaining a high adsorption capacity. Stirring at room temperature for 15 min forms a modified solution for later use. The silica aerogel is immersed in the modified solution and refluxed at 80℃ for 12 h under nitrogen protection. After the reaction, the product is washed 5 times with anhydrous ethanol and finally vacuum dried at 80℃. The silanol groups after hydrolysis of 3-aminopropyltriethoxysilane undergo a condensation reaction with the silanol groups on the surface of silica aerogel to form a strong Si-O-Si covalent bond, thereby chemically grafting its own aminopropyl group onto the entire inner surface of the aerogel, achieving high capacity and strong selectivity for capturing heavy metal ions. At the same time, it can also change the charge under different pH conditions to achieve effective adsorption of various forms of heavy metals (cations and complex anions). The stable covalent bond connection ensures that the amino functional group will not leach out during use and regeneration, improving the stability and effectiveness of the aerogel material's adsorption performance, thus obtaining amino-modified silica aerogel.

[0036] S2. Add 1.0 g of MW5000 polyacrylic acid to 100 mL of pH 5.0 MES buffer. The carboxyl groups introduced by polyacrylic acid mainly adsorb heavy metal ions through ion exchange, and can achieve broad-spectrum and efficient adsorption in conjunction with amino sites. Furthermore, under acidic conditions, although the carboxyl groups are partially protonated, there are still a large number of carboxyl groups on the long chain of polyacrylic acid that can undergo ion exchange. Under alkaline conditions, the carboxyl groups, as negatively charged groups, can assist in electrostatic adsorption. Then add 0.5 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.2 g of N-hydroxysuccinimide, and stir for 30 min to form an activated polyacrylic acid solution for later use. Immerse the amino-modified silica aerogel described in step S1 into the activated polyacrylic acid solution, and adjust the pH to 8 within 1 min using a 0.4% pre-cooled sodium hydroxide solution. 0.0, then placed in a 30℃ constant temperature water bath and stirred for 24h. The aerogel was taken out and thoroughly soaked and washed with deionized water for 36h, with the deionized water being replaced every 2h until the washing liquid showed no chloride ions when tested with silver nitrate and no amino byproducts when tested with ninhydrin. Finally, the washed product was soaked and replaced with anhydrous ethanol and tert-butanol three times in sequence, 2h each time, and then freeze-dried. Polyacrylic acid long chains were grafted onto the surface of amino-modified silica aerogel. The synergistic cooperation of carboxyl and amino groups provided a large number of high-affinity adsorption sites, which significantly improved the adsorption capacity. The dissociation state of the carboxyl groups on the polyacrylic acid long chains at different pH levels perfectly complemented and relayed the protonated state of the amino groups, so that at least one functional group was always in a highly efficient working state in a wide pH range, reducing the adverse effects of acid and alkaline environments on adsorption performance, and obtaining polyacrylic acid grafted amino-modified silica aerogel material.

[0037] S3. Grind the polyacrylic acid-grafted amino-modified silica aerogel material described in step S2, controlling the particle size to 300 mesh, to obtain aerogel powder for later use. Grind the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material, controlling the particle size to 300 mesh, to obtain ternary composite powder for later use. Weigh 0.5g of genipin and add it to 200mL of pH 9.0 PBS buffer, sonicate at 40℃ for 40min to form a genipin crosslinking solution for later use. Then mix the aerogel powder and the ternary composite powder and add them to 100mL of deionized water, sonicate under ice bath for 30min to form a suspension slurry for later use. Then slowly add the genipin crosslinking solution to the suspension slurry at a rate of 2 drops / second through a constant pressure dropping funnel, while stirring at 300rpm. After the addition is complete, place it in a 37℃ water bath and stir at 250rpm for 48h. Filter, and wash the filter cake repeatedly with deionized water. The product was washed until the washing liquid was colorless and clear, and then soaked in ethanol solutions with mass fractions of 30%, 50%, 70%, and 90% for 6 hours each time. Finally, it was soaked in anhydrous ethanol and tert-butanol for 6 hours. The product was then removed, freeze-dried, pre-frozen at -50℃ for 8 hours, and then dried at -60℃ and 8 Pa vacuum for 72 hours. Using polyacrylic acid-grafted amino-modified silica aerogel as a rigid framework network and reinforced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent as flexible sites, a crosslinking agent anchors and interweaves the two to form a stable, uniform, and highly interconnected three-dimensional network. It also has three powerful functional groups: carboxyl, amino, and phenolic hydroxyl. Through broad-spectrum and efficient chelation and ion exchange, it achieves ultra-high capacity adsorption of heavy metal ions and ultra-wide pH range adaptability, further enhancing the purification and adsorption effect of wastewater, and obtaining a high-performance adsorbent material for wastewater treatment.

[0038] Example 2

[0039] This embodiment proposes a high-performance adsorbent material for wastewater treatment, comprising the following components in parts by weight: 20 parts of enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material, 20 parts of polyacrylic acid-grafted amino-modified silica aerogel material, and 3 parts of genipin.

[0040] The enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material comprises the following components in parts by weight: 70 parts deacetylated konjac glucomannan, 10 parts nanocellulose, 8 parts chitosan, and 20 parts tannin.

[0041] The preparation method of the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material specifically includes the following steps:

[0042] (1) Konjac glucomannan was dispersed in 500 mL of 40% ethanol solution. The amount of konjac glucomannan added was 8.0 g. Konjac glucomannan swelled in water to form a three-dimensional network framework, which provided a stable support and a large dispersion and attachment space for subsequent grafting modification of substances. This facilitated the full exposure of various active adsorption sites and improved the site utilization rate. At the same time, under alkaline conditions, the hydroxyl groups on the konjac glucomannan molecular chain were deprotonated and became negatively charged, which could adsorb heavy metal cations through electrostatic interaction. The mixture was stirred and heated to 40°C, and then 8.0 g of anhydrous sodium carbonate was added and stirred for 1 h. After cooling at room temperature, the mixture was filtered, and the solid product was transferred to a beaker. 100 mL of distilled water was added to disperse the mixture. 0.1 mol / L hydrochloric acid standard solution was added dropwise under stirring to neutralize the mixture until the pH of the suspension was 6.5. The mixture was filtered, and the precipitate was then treated with 3% ethanol solution. Washed three times with 0% ethanol solution, and finally washed three times with distilled water, and then vacuum dried at 100℃, the acetyl groups on the side chains of konjac glucomannan molecules were partially or completely removed, directly exposing more active hydroxyl groups, thereby enhancing the hydrophilicity and reactivity of the molecules. The intramolecular and intermolecular hydrogen bonding after deacetylation is enhanced, making it easier to form an ordered and stable three-dimensional network gel structure in water. The micropores and channels in the gel network provide pathways for the diffusion of heavy metal ions into the interior of the material, allowing the internal active sites to participate in adsorption, which is beneficial to improving the adsorption capacity. Furthermore, under acidic conditions, the gel network of deacetylated konjac glucomannan can still maintain its basic structure and remain insoluble, providing a stable working platform for other components. Under alkaline conditions, it can assist the adsorption of metal cations through electrostatic attraction, thereby broadening the applicable pH range and obtaining deacetylated konjac glucomannan.

[0043] (2) Add 1.0 g of dried nanocellulose to 50 mL of distilled water. The nanocellulose can be interwoven into a nanoscale rigid network skeleton. Under extreme pH conditions, it can effectively prevent excessive swelling and collapse of chitosan and deacetylated konjac glucomannan, ensuring that the material can maintain its integrity over a wide pH range. At the same time, the stable network skeleton prevents the gel from densifying, maximizing the maintenance and exposure of the pores and channels inside the material, providing a huge adhesion area for subsequent grafting, so that heavy metal ions can more fully contact the adsorption sites, thereby improving the overall adsorption capacity. First, stir magnetically for 10 min, then sonicate in an ice bath for 10 min. The sonication power is 250 W, and the sonication time is 2 s with an interval of 1 s to form a nanocellulose dispersion for later use. Weigh 0.8 g of chitosan powder with a deacetylation degree ≥90% and add it to 100 mL of 1% acetic acid aqueous solution. Stir in a 40℃ water bath for 1 h to form a nanocellulose dispersion. Prepare a chitosan-acetic acid solution for later use. Then, add 200 mL of distilled water to a three-necked flask. While stirring at 200 rpm, first add the nanocellulose dispersion. Keep the stirring speed constant and slowly add the chitosan-acetic acid solution at a rate of 1 drop / second using a constant pressure dropping funnel. After the addition is complete, continue stirring for 30 min. Then, add the deacetylated konjac glucomannan described in step (1) and add distilled water to ensure the reaction system reaches 300 mL. Stir at room temperature for 1 h. With deacetylated konjac glucomannan as the main body of the three-dimensional network and nanocellulose as the reinforcing skeleton to improve the stability of the structure, the chitosan is firmly fixed in the stable network formed by the deacetylated konjac glucomannan and nanocellulose. The large number of amino groups on the chitosan molecular chain play an adsorption role as a strong functional group for binding heavy metals and can maintain structural integrity over a wider pH range. At the same time, the deacetylated konjac glucomannan gel network in the composite substrate has hydrophilicity and weak buffering capacity, and can slightly consume H+. + To a certain extent, this protects the amino groups of chitosan and slows down its protonation, thereby broadening the effective lower limit of pH operation of the material to a stronger acidic environment, resulting in a composite substrate slurry.

[0044] (3) Add ascorbic acid and tannin to the composite substrate slurry described in step (2). The amounts of ascorbic acid and tannin added are 0.5g and 2.0g, respectively. Tannin is rich in catechol / pyrogallol structure. Its phenolic hydroxyl group has a strong chelating ability for heavy metal ions such as copper and lead. One molecule of tannin can provide multiple coordination sites at the same time, and can form more stable chelates with metal ions with higher coordination ratios, thereby effectively improving the adsorption capacity. In addition, the phenolic hydroxyl group of tannin has a low degree of protonation, and its chelating effect is far less affected by acidity than that of amino groups. It becomes a strong acidic adsorption medium under strong acid conditions. The main adsorption functional groups significantly extend the effective working pH limit of the material. Even under alkaline conditions, tannins maintain good chelating ability for metal hydroxyl complexes, further maintaining the material's adsorption performance at higher pH levels. Under a nitrogen atmosphere, the mixture was stirred at 200 rpm for 20 min, then 30 mL of 3.4% hydrogen peroxide solution was added, and the reaction was carried out at 25℃ for 8 h. After filtration, the solid was first soaked and washed twice with 100 mL of 0.4% sodium hydroxide solution, stirring for 5 min each time, followed by filtration. Then, it was treated with 10... The product was soaked and washed twice in a 1% sodium dodecyl sulfate aqueous solution at 50℃, with stirring for 10 min each time, followed by filtration. Finally, it was washed three times with distilled water. The solid product was then vacuum dried at 60℃. The tannin molecules underwent a free radical reaction initiated by ascorbic acid and hydrogen peroxide, resulting in the abstraction of hydrogen atoms from the phenolic hydroxyl groups. The formed phenoxy radicals covalently coupled with the active hydrogen sites on the deacetylated konjac glucomannan and chitosan molecular chains, forming a strong carbon-carbon bond or ether bond chemically bonded to the entire network, thus creating a nanocellulose-reinforced deacetylated konjac glucomannan... The polysaccharide / chitosan network contains a stable complex of tannin molecules covalently bonded to its surface and interior. The entire framework surface is covered with a layer of hook-like active surfaces rich in catechol / triphenol structures, introducing a large number of highly active sites. It also possesses phenolic hydroxyl, amino, and hydroxyl functional groups, which greatly enhances the adsorption capacity of heavy metals and significantly improves the material's adaptability over a wide pH range, especially under strongly acidic conditions. This allows it to maintain excellent adsorption performance in different water environments, resulting in an enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material.

[0045] This embodiment provides a method for preparing a high-performance adsorption material for wastewater treatment, specifically including the following steps:

[0046] S1. Add 25 mL of tetraethyl orthosilicate to 40 mL of anhydrous ethanol and stir until homogeneous. Adjust the pH to 3.0 with 0.1 mol / L hydrochloric acid standard solution. Stir magnetically at 50 °C for 1 h, cool to room temperature, and let stand for 2 h. The resulting gel ages at room temperature for 24 h. Then add anhydrous ethanol and continue aging in a 40 °C water bath for 24 h. Remove the wet gel and perform solvent exchange with anhydrous ethanol and n-hexane sequentially for 36 h, changing the solvent every 6 h. Freeze-dry the solvent-exchanged wet gel to obtain silica aerogel for later use. Add 18 mL of 3-aminopropyltriethoxysilane to 500 mL of anhydrous ethanol that has been dried with 3A molecular sieves. The amino group at the end of 3-aminopropyltriethoxysilane can form stable coordination bonds with heavy metal ions such as copper and lead, improving the chemical adsorption capacity. Furthermore, under acidic conditions, the amino group is highly protonated to -NH3. + It can adsorb metal complex anions through strong positive electrostatic adsorption. Under alkaline conditions, the amino group is completely deprotonated to -NH2, still maintaining a high adsorption capacity. After stirring at room temperature for 10 min, a modified solution is formed for later use. The silica aerogel is immersed in the modified solution and refluxed at 70℃ for 8 h under nitrogen protection. After the reaction, the product is washed three times with anhydrous ethanol and finally vacuum dried at 60℃. The silanol groups after hydrolysis of 3-aminopropyltriethoxysilane undergo a condensation reaction with the silanol groups on the surface of silica aerogel to form a strong Si-O-Si covalent bond, thereby chemically grafting its own aminopropyl group onto the entire inner surface of the aerogel, achieving high capacity and strong selectivity for capturing heavy metal ions. At the same time, it can also change the charge under different pH conditions to achieve effective adsorption of various forms of heavy metals (cations and complex anions). The stable covalent bond connection ensures that the amino functional group will not be leached out during use and regeneration, improving the stability and effectiveness of the adsorption performance of the aerogel material, thus obtaining amino-modified silica aerogel.

[0047] S2. Add 0.8 g of MW5000 polyacrylic acid to 100 mL of pH 4.5 MES buffer. The carboxyl groups introduced by polyacrylic acid mainly adsorb heavy metal ions through ion exchange, and can achieve broad-spectrum and efficient adsorption in conjunction with amino sites. Furthermore, under acidic conditions, although the carboxyl groups are partially protonated, there are still a large number of carboxyl groups on the long chain of polyacrylic acid that can undergo ion exchange. Under alkaline conditions, the carboxyl groups, as negatively charged groups, can assist in electrostatic adsorption. Then add 0.3 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.1 g of N-hydroxysuccinimide, and stir for 20 min to form an activated polyacrylic acid solution for later use. Immerse the amino-modified silica aerogel described in step S1 into the activated polyacrylic acid solution, and adjust the pH to 7 within 2 min using a 0.4% pre-cooled sodium hydroxide solution. 5, then placed in a 25℃ constant temperature water bath and stirred for 12h. The aerogel was taken out and thoroughly soaked and washed with deionized water for 24h, with the deionized water being replaced every 2h until the washing liquid showed no chloride ions when tested with silver nitrate and no amino byproducts when tested with ninhydrin. Finally, the washed product was soaked and replaced twice with anhydrous ethanol and tert-butanol, 2h each time, and then freeze-dried. The polyacrylic acid long chain was grafted onto the surface of the amino-modified silica aerogel. The synergistic cooperation of carboxyl and amino groups provided a large number of high-affinity adsorption sites, which significantly improved the adsorption capacity. The dissociation state of the carboxyl group on the polyacrylic acid long chain at different pH levels and the protonated state of the amino group formed a perfect complement and relay, so that at least one functional group was always in a highly efficient working state in a wide pH range, reducing the adverse effects of acid and alkaline environments on adsorption performance, and obtaining the polyacrylic acid grafted amino-modified silica aerogel material.

[0048] S3. Grind the polyacrylic acid-grafted amino-modified silica aerogel material described in step S2, controlling the particle size to 100 mesh, to obtain aerogel powder for later use. Grind the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material, controlling the particle size to 100 mesh, to obtain ternary composite powder for later use. Weigh 0.3g of genipin and add it to 200mL of pH 8.0 PBS buffer, sonicate at 40℃ for 30min to form a genipin crosslinking solution for later use. Then mix the aerogel powder and the ternary composite powder and add them to 100mL of deionized water, sonicate under ice bath for 20min to form a suspension slurry for later use. Then slowly add the genipin crosslinking solution to the suspension slurry at a rate of 1 drop / second through a constant pressure dropping funnel, while stirring at 200rpm. After the addition is complete, place it in a 37℃ water bath and stir at 200rpm for 24h. Filter, and wash the filter cake repeatedly with deionized water. The product was washed until the washing liquid was colorless and clear, and then soaked in ethanol solutions with mass fractions of 30%, 50%, 70%, and 90% for 4 hours each time. Finally, it was soaked in anhydrous ethanol and tert-butanol for 4 hours. The product was then removed, freeze-dried, pre-frozen at -50℃ for 6 hours, and then dried at -60℃ and 6Pa vacuum for 48 hours. Using polyacrylic acid-grafted amino-modified silica aerogel as a rigid framework network and reinforced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent as flexible sites, a crosslinking agent anchors and interweaves the two to form a stable, uniform, and highly interconnected three-dimensional network. It also has three powerful functional groups: carboxyl, amino, and phenolic hydroxyl. Through broad-spectrum and efficient chelation and ion exchange, it achieves ultra-high capacity adsorption of heavy metal ions and ultra-wide pH range adaptability, further enhancing the purification and adsorption effect of wastewater, and obtaining a high-performance adsorbent material for wastewater treatment.

[0049] Example 3

[0050] This embodiment proposes a high-performance adsorbent material for wastewater treatment, comprising the following components in parts by weight: 30 parts of enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material, 10 parts of polyacrylic acid-grafted amino-modified silica aerogel material, and 4 parts of genipin.

[0051] The enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material comprises the following components in parts by weight: 77 parts deacetylated konjac glucomannan, 12.5 parts nanocellulose, 9 parts chitosan, and 25 parts tannin.

[0052] The preparation method of the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material specifically includes the following steps:

[0053] (1) Konjac glucomannan was dispersed in 500 mL of 40% ethanol solution. The amount of konjac glucomannan added was 9.0 g. Konjac glucomannan swelled in water to form a three-dimensional network framework, which provided a stable support and a large dispersion and attachment space for subsequent grafting modification of substances. This facilitated the full exposure of various active adsorption sites and improved the site utilization rate. At the same time, under alkaline conditions, the hydroxyl groups on the konjac glucomannan molecular chain were deprotonated and became negatively charged, which could adsorb heavy metal cations through electrostatic interaction. The mixture was stirred and heated to 45°C, and then 9.0 g of anhydrous sodium carbonate was added and stirred for 1.5 h. After cooling at room temperature, the mixture was filtered, and the solid product was transferred to a beaker. 100 mL of distilled water was added to disperse the mixture. 0.1 mol / L hydrochloric acid standard solution was added dropwise under stirring to neutralize the mixture until the pH of the suspension was 7.0. The mixture was filtered, and the precipitate was then treated with ethanol solution of 40% ethanol solution. Washed four times with 30% ethanol solution, and finally washed four times with distilled water, and then vacuum dried at 100℃, the acetyl groups on the side chains of konjac glucomannan molecules were partially or completely removed, directly exposing more active hydroxyl groups, thereby enhancing the hydrophilicity and reactivity of the molecules. The intramolecular and intermolecular hydrogen bonding after deacetylation is enhanced, making it easier to form an ordered and stable three-dimensional network gel structure in water. The micropores and channels in the gel network provide pathways for the diffusion of heavy metal ions into the interior of the material, allowing the internal active sites to participate in adsorption, which is beneficial to improving the adsorption capacity. Furthermore, under acidic conditions, the gel network of deacetylated konjac glucomannan can still maintain its basic structure and remain insoluble, providing a stable working platform for other components. Under alkaline conditions, it can assist the adsorption of metal cations through electrostatic attraction, thereby broadening the applicable pH range and obtaining deacetylated konjac glucomannan.

[0054] (2) Add 1.25 g of dried nanocellulose to 50 mL of distilled water. The nanocellulose can be interwoven into a nanoscale rigid network skeleton. Under extreme pH conditions, it can effectively prevent excessive swelling and collapse of chitosan and deacetylated konjac glucomannan, ensuring that the material can maintain its integrity over a wide pH range. At the same time, the stable network skeleton prevents the gel from densifying, maximizing the maintenance and exposure of the pores and channels inside the material, providing a huge adhesion area for subsequent grafting, so that heavy metal ions can more fully contact the adsorption sites, thereby improving the overall adsorption capacity. First, stir magnetically for 15 min, then sonicate in an ice bath for 15 min. The sonication power is 275 W, and the sonication time is 2 s with a 1 s interval to form a nanocellulose dispersion for later use. Weigh 0.9 g of chitosan powder with a deacetylation degree ≥90% and add it to 100 mL of 1% acetic acid aqueous solution. Stir in a 45℃ water bath for 1.5 h to form Chitosan acetic acid solution was prepared for use. Then, 200 mL of distilled water was added to a three-necked flask. While stirring at 225 rpm, nanocellulose dispersion was added first. While maintaining the stirring speed, chitosan acetic acid solution was slowly added at a rate of 1.5 drops / second using a constant pressure dropping funnel. After the addition was completed, stirring was continued for 35 min. Then, deacetylated konjac glucomannan from step (1) was added, and distilled water was added to ensure that the reaction system reached 300 mL. The mixture was stirred at room temperature for 1.5 h. With deacetylated konjac glucomannan as the main body of the three-dimensional network and nanocellulose as the reinforcing skeleton to improve the stability of the structure, chitosan was firmly fixed in the stable network formed by deacetylated konjac glucomannan and nanocellulose. A large number of amino groups on the chitosan molecular chain played an adsorption role as strong functional groups for binding heavy metals, and could maintain structural integrity over a wider pH range. At the same time, the deacetylated konjac glucomannan gel network in the composite substrate had hydrophilicity and weak buffering capacity, and could slightly consume H+. + To a certain extent, this protects the amino groups of chitosan and slows down its protonation, thereby broadening the effective lower limit of pH operation of the material to a stronger acidic environment, resulting in a composite substrate slurry.

[0055] (3) Add ascorbic acid and tannin to the composite substrate slurry described in step (2). The amounts of ascorbic acid and tannin added are 0.75g and 2.5g, respectively. Tannin is rich in catechol / pyrogallol structure. Its phenolic hydroxyl group has a strong chelating ability for heavy metal ions such as copper and lead. One molecule of tannin can provide multiple coordination sites at the same time, and can form more stable chelates with metal ions with higher coordination ratios, thereby effectively improving the adsorption capacity. In addition, the phenolic hydroxyl group of tannin has a low degree of protonation, and its chelating effect is far less affected by acidity than that of amino groups. It becomes a strong acidic adsorption medium under strong acid conditions. The main adsorption functional groups significantly extend the effective working pH limit of the material. Even under alkaline conditions, tannins maintain good chelating ability for metal hydroxyl complexes, further maintaining the material's adsorption performance at higher pH levels. Under a nitrogen atmosphere, the mixture was stirred at 225 rpm for 25 min, then 30 mL of 3.4% hydrogen peroxide solution was added, and the reaction was carried out at 25℃ for 8.5 h. After filtration, the solid was first soaked and washed twice with 100 mL of 0.4% sodium hydroxide solution, stirring for 5 min each time, followed by filtration. Then, it was treated with 1... The product was soaked and washed twice in 1% sodium dodecyl sulfate aqueous solution at 50℃, with stirring for 10 min each time, followed by filtration. Finally, it was washed four times with distilled water. The solid product was then vacuum dried at 60℃. The tannin molecules underwent a free radical reaction initiated by ascorbic acid and hydrogen peroxide, resulting in the removal of hydrogen from the phenolic hydroxyl groups. The formed phenoxy radicals covalently coupled with the active hydrogen sites on the deacetylated konjac glucomannan and chitosan molecular chains, forming a strong carbon-carbon bond or ether bond chemically bonded to the entire network, thus creating a nanocellulose-reinforced deacetylated konjac glucomannan... The polysaccharide / chitosan network contains a stable complex of tannin molecules covalently bonded to its surface and interior. The entire framework surface is covered with a layer of hook-like active surfaces rich in catechol / triphenol structures, introducing a large number of highly active sites. It also possesses phenolic hydroxyl, amino, and hydroxyl functional groups, which greatly enhances the adsorption capacity of heavy metals and significantly improves the material's adaptability over a wide pH range, especially under strongly acidic conditions. This allows it to maintain excellent adsorption performance in different water environments, resulting in an enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material.

[0056] This embodiment provides a method for preparing a high-performance adsorption material for wastewater treatment, specifically including the following steps:

[0057] S1. Add 25 mL of tetraethyl orthosilicate to 40 mL of anhydrous ethanol and stir until homogeneous. Adjust the pH to 3.5 with 0.1 mol / L hydrochloric acid standard solution. Stir magnetically at 55 °C for 1.5 h, cool to room temperature, and let stand for 3 h. The resulting gel is aged at room temperature for 24 h. Then, add anhydrous ethanol and continue aging in a 40 °C water bath for 24 h. Remove the wet gel and perform solvent exchange with anhydrous ethanol and n-hexane sequentially for 42 h, changing the solvent every 6 h. Freeze-dry the solvent-exchanged wet gel to obtain silica aerogel for later use. Add 21 mL of 3-aminopropyltriethoxysilane to 500 mL of anhydrous ethanol that has been dried with 3A molecular sieves. The amino group at the end of 3-aminopropyltriethoxysilane can form stable coordination bonds with heavy metal ions such as copper and lead, improving the chemical adsorption capacity. Furthermore, under acidic conditions, the amino group is highly protonated to -NH3. + It can adsorb metal complex anions through strong positive electrostatic adsorption. Under alkaline conditions, the amino group is completely deprotonated to -NH2, still maintaining a high adsorption capacity. Stirring at room temperature for 12.5 min forms a modified solution for later use. The silica aerogel is immersed in the modified solution and refluxed at 75℃ for 10 h under nitrogen protection. After the reaction, the product is washed four times with anhydrous ethanol and finally vacuum dried at 70℃. The silanol groups after hydrolysis of 3-aminopropyltriethoxysilane undergo a condensation reaction with the silanol groups on the surface of silica aerogel to form a strong Si-O-Si covalent bond, thereby chemically grafting its own aminopropyl group onto the entire inner surface of the aerogel, achieving high capacity and strong selectivity for capturing heavy metal ions. At the same time, it can also change the charge under different pH conditions to achieve effective adsorption of various forms of heavy metals (cations and complex anions). The stable covalent bond connection ensures that the amino functional group will not leach out during use and regeneration, improving the stability and effectiveness of the aerogel material's adsorption performance, thus obtaining amino-modified silica aerogel.

[0058] S2. Add 0.9 g of MW5000 polyacrylic acid to 100 mL of pH 4.7 MES buffer. The carboxyl groups introduced by polyacrylic acid mainly adsorb heavy metal ions through ion exchange, and can achieve broad-spectrum and efficient adsorption in conjunction with amino sites. Furthermore, under acidic conditions, although the carboxyl groups are partially protonated, there are still a large number of carboxyl groups on the long chain of polyacrylic acid that can undergo ion exchange. Under alkaline conditions, the carboxyl groups, as negatively charged groups, can assist in electrostatic adsorption. Then add 0.4 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.15 g of N-hydroxysuccinimide, and stir for 25 min to form an activated polyacrylic acid solution for later use. Immerse the amino-modified silica aerogel described in step S1 into the activated polyacrylic acid solution, and adjust the pH to 7 within 1.5 min using a 0.4% pre-cooled sodium hydroxide solution. 7. Then, place the mixture in a constant temperature water bath at 27.5℃ and stir for 18 hours. Remove the aerogel and soak it thoroughly in deionized water for 30 hours, changing the deionized water every 2 hours until the washing liquid is free of chloride ions when tested with silver nitrate and free of amino byproducts when tested with ninhydrin. Finally, soak the washed product in anhydrous ethanol and tert-butanol for 2 hours each time, and freeze-dry it. The polyacrylic acid long chain is grafted onto the surface of the amino-modified silica aerogel. The synergistic cooperation of carboxyl and amino groups provides a large number of high-affinity adsorption sites, which significantly improves the adsorption capacity. The dissociation state of the carboxyl group on the polyacrylic acid long chain at different pH levels is perfectly complementary and relayed with the protonated state of the amino group, so that at least one functional group is always in a highly efficient working state in a wide pH range, reducing the adverse effects of acid and alkaline environments on adsorption performance. The resulting polyacrylic acid grafted amino-modified silica aerogel material is obtained.

[0059] S3. Grind the polyacrylic acid-grafted amino-modified silica aerogel material described in step S2, controlling the particle size to 200 mesh, to obtain aerogel powder for later use. Grind the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material, controlling the particle size to 200 mesh, to obtain ternary composite powder for later use. Weigh 0.4 g of genipin and add it to 200 mL of pH 8.5 PBS buffer, sonicate at 40°C for 35 min to form a genipin crosslinking solution for later use. Then mix the aerogel powder and the ternary composite powder and add them to 100 mL of deionized water, sonicate under ice bath for 25 min to form a suspension slurry for later use. Then slowly add the genipin crosslinking solution to the suspension slurry at a rate of 1.5 drops / second through a constant pressure dropping funnel, while stirring at 250 rpm. After the addition is complete, place it in a 37°C water bath and stir at 225 rpm for 36 h. Filter, and rinse the filter cake repeatedly with deionized water. Wash until the washing liquid is colorless and clear, then soak in ethanol solutions with mass fractions of 30%, 50%, 70%, and 90% for 5 hours each time. Finally, soak in anhydrous ethanol and tert-butanol for 5 hours. Remove the product, freeze-dry it, first pre-freezing at -50℃ for 7 hours, then drying it at -60℃ and a vacuum of 7 Pa for 60 hours. Using polyacrylic acid-grafted amino-modified silica aerogel as a rigid framework network and reinforced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent as flexible sites, a crosslinking agent anchors and interweaves the two to form a stable, uniform, and highly interconnected three-dimensional network. It also possesses three powerful functional groups: carboxyl, amino, and phenolic hydroxyl groups. Through broad-spectrum and efficient chelation and ion exchange, it achieves ultra-high capacity adsorption of heavy metal ions and ultra-wide pH range adaptability, further enhancing the purification and adsorption effect of wastewater, and obtaining a high-performance adsorbent material for wastewater treatment.

[0060] Example 4

[0061] This embodiment proposes a high-performance adsorbent material for wastewater treatment, comprising the following components in parts by weight: 40 parts of enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material, 10 parts of polyacrylic acid-grafted amino-modified silica aerogel material, and 5 parts of genipin.

[0062] The enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material comprises the following components in parts by weight: 85 parts deacetylated konjac glucomannan, 10 parts nanocellulose, 10 parts chitosan, and 20 parts tannin.

[0063] The preparation method of the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material specifically includes the following steps:

[0064] (1) Konjac glucomannan was dispersed in 500 mL of 40% ethanol solution. The amount of konjac glucomannan added was 10.0 g. Konjac glucomannan swelled in water to form a three-dimensional network framework, which provided a stable support and a large dispersion and attachment space for subsequent grafting modification of substances. This facilitated the full exposure of various active adsorption sites and improved the site utilization rate. At the same time, under alkaline conditions, the hydroxyl groups on the konjac glucomannan molecular chain were deprotonated and became negatively charged, which could adsorb heavy metal cations through electrostatic interaction. The mixture was stirred and heated to 50°C, and then 10.0 g of anhydrous sodium carbonate was added and stirred for 2 hours. After cooling at room temperature, the mixture was filtered, and the solid product was transferred to a beaker. 100 mL of distilled water was added to disperse the mixture. 0.1 mol / L hydrochloric acid standard solution was added dropwise under stirring to neutralize the mixture until the pH of the suspension was 7.5. The mixture was then filtered, and the precipitate was further treated with ethanol solution of 40% ethanol solution. Washed five times with 30% ethanol solution, and finally washed five times with distilled water, and then vacuum dried at 100℃, the acetyl groups on the side chains of konjac glucomannan molecules were partially or completely removed, directly exposing more active hydroxyl groups, thereby enhancing the hydrophilicity and reactivity of the molecules. The intramolecular and intermolecular hydrogen bonding after deacetylation is enhanced, making it easier to form an ordered and stable three-dimensional network gel structure in water. The micropores and channels in the gel network provide pathways for the diffusion of heavy metal ions into the interior of the material, allowing the internal active sites to participate in adsorption, which is beneficial to improving the adsorption capacity. Furthermore, under acidic conditions, the gel network of deacetylated konjac glucomannan can still maintain its basic structure and remain insoluble, providing a stable working platform for other components. Under alkaline conditions, it can assist the adsorption of metal cations through electrostatic attraction, thereby broadening the applicable pH range and obtaining deacetylated konjac glucomannan.

[0065] (2) Add 1.0 g of dried nanocellulose to 50 mL of distilled water. The nanocellulose can be interwoven into a nanoscale rigid network skeleton. Under extreme pH conditions, it can effectively prevent excessive swelling and collapse of chitosan and deacetylated konjac glucomannan, ensuring that the material can maintain its integrity over a wide pH range. At the same time, the stable network skeleton prevents the gel from densifying, maximizing the maintenance and exposure of the pores and channels inside the material, providing a huge adhesion area for subsequent grafting, so that heavy metal ions can more fully contact the adsorption sites, thereby improving the overall adsorption capacity. First, stir magnetically for 20 min, then sonicate in an ice bath for 20 min. The sonication power is 300 W, and the sonication time is 2 s with an interval of 1 s to form a nanocellulose dispersion for later use. Weigh 1.0 g of chitosan powder with a deacetylation degree ≥90% and add it to 100 mL of 1% acetic acid aqueous solution. Stir in a 50℃ water bath for 2 h to form a nanocellulose dispersion. Prepare a chitosan-acetic acid solution for later use. Then, add 200 mL of distilled water to a three-necked flask and stir at 250 rpm. First, add the nanocellulose dispersion while maintaining the stirring speed. At the same time, use a constant pressure dropping funnel to slowly add the chitosan-acetic acid solution at a rate of 1 drop / second. After the addition is complete, continue stirring for 40 min. Then, add the deacetylated konjac glucomannan described in step (1) and add distilled water to ensure that the reaction system reaches 300 mL. Stir at room temperature for 2 h. With deacetylated konjac glucomannan as the main body of the three-dimensional network and nanocellulose as the reinforcing skeleton to improve the stability of the structure, the chitosan is firmly fixed in the stable network formed by the deacetylated konjac glucomannan and nanocellulose. The large number of amino groups on the chitosan molecular chain play an adsorption role as a strong functional group for binding heavy metals and can maintain structural integrity over a wider pH range. At the same time, the deacetylated konjac glucomannan gel network in the composite substrate has hydrophilicity and weak buffering capacity, and can slightly consume H+. + To a certain extent, this protects the amino groups of chitosan and slows down its protonation, thereby broadening the effective lower limit of pH operation of the material to a stronger acidic environment, resulting in a composite substrate slurry.

[0066] (3) Add ascorbic acid and tannin to the composite substrate slurry described in step (2). The amounts of ascorbic acid and tannin added are 1.0g and 2.0g, respectively. Tannin is rich in catechol / pyrogallol structure. Its phenolic hydroxyl group has a strong chelating ability for heavy metal ions such as copper and lead. One molecule of tannin can provide multiple coordination sites at the same time, and can form more stable chelates with metal ions with higher coordination ratios, thereby effectively improving the adsorption capacity. In addition, the phenolic hydroxyl group of tannin has a low degree of protonation, and its chelating effect is far less affected by acidity than that of amino groups. It becomes a strong acidic adsorption medium under strong acid conditions. The main adsorption functional groups significantly extend the effective working pH limit of the material. Even under alkaline conditions, tannins maintain good chelating ability for metal hydroxyl complexes, further maintaining the material's adsorption performance at higher pH levels. Under a nitrogen atmosphere, the mixture was stirred at 250 rpm for 30 min, then 30 mL of 3.4% hydrogen peroxide solution was added, and the reaction was carried out at 25℃ for 9 h. After filtration, the solid was first soaked and washed three times with 100 mL of 0.4% sodium hydroxide solution, stirring for 5 min each time, followed by filtration. Then, it was treated with 10... The product was soaked and washed three times in a 1% sodium dodecyl sulfate aqueous solution at 50℃, with stirring for 10 min each time, followed by filtration. Finally, it was washed five times with distilled water. The solid product was then vacuum dried at 60℃. The tannin molecules underwent a free radical reaction initiated by ascorbic acid and hydrogen peroxide, resulting in the removal of hydrogen from the phenolic hydroxyl groups. The formed phenoxy radicals covalently coupled with the active hydrogen sites on the deacetylated konjac glucomannan and chitosan molecular chains, forming a strong carbon-carbon bond or ether bond chemically bonded to the entire network, thus creating a nanocellulose-reinforced deacetylated konjac glucomannan... The polysaccharide / chitosan network contains a stable complex of tannin molecules covalently bonded to its surface and interior. The entire framework surface is covered with a layer of hook-like active surfaces rich in catechol / triphenol structures, introducing a large number of highly active sites. It also possesses phenolic hydroxyl, amino, and hydroxyl functional groups, which greatly enhances the adsorption capacity of heavy metals and significantly improves the material's adaptability over a wide pH range, especially under strongly acidic conditions. This allows it to maintain excellent adsorption performance in different water environments, resulting in an enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material.

[0067] This embodiment provides a method for preparing a high-performance adsorption material for wastewater treatment, specifically including the following steps:

[0068] S1. Add 25 mL of tetraethyl orthosilicate to 40 mL of anhydrous ethanol and stir until homogeneous. Adjust the pH to 4.0 with 0.1 mol / L hydrochloric acid standard solution. Stir magnetically at 50-60℃ for 2 h, cool to room temperature, and let stand for 4 h. The resulting gel ages at room temperature for 24 h. Then add anhydrous ethanol and continue aging in a 40℃ water bath for 24 h. Remove the wet gel and perform solvent exchange with anhydrous ethanol and n-hexane sequentially for 48 h, changing the solvent every 6 h. Freeze-dry the solvent-exchanged wet gel to obtain silica aerogel for later use. Add 18 mL of 3-aminopropyltriethoxysilane to 500 mL of anhydrous ethanol that has been dried with 3A molecular sieves. The amino group at the end of 3-aminopropyltriethoxysilane can form stable coordination bonds with heavy metal ions such as copper and lead, improving the chemical adsorption capacity. Under acidic conditions, the amino group is highly protonated to -NH3. + It can adsorb metal complex anions through strong positive electrostatic adsorption. Under alkaline conditions, the amino group is completely deprotonated to -NH2, still maintaining a high adsorption capacity. Stirring at room temperature for 15 min forms a modified solution for later use. The silica aerogel is immersed in the modified solution and refluxed at 80℃ for 12 h under nitrogen protection. After the reaction, the product is washed 5 times with anhydrous ethanol and finally vacuum dried at 80℃. The silanol groups after hydrolysis of 3-aminopropyltriethoxysilane undergo a condensation reaction with the silanol groups on the surface of silica aerogel to form a strong Si-O-Si covalent bond, thereby chemically grafting its own aminopropyl group onto the entire inner surface of the aerogel, achieving high capacity and strong selectivity for capturing heavy metal ions. At the same time, it can also change the charge under different pH conditions to achieve effective adsorption of various forms of heavy metals (cations and complex anions). The stable covalent bond connection ensures that the amino functional group will not leach out during use and regeneration, improving the stability and effectiveness of the aerogel material's adsorption performance, thus obtaining amino-modified silica aerogel.

[0069] S2. Add 0.8 g of MW5000 polyacrylic acid to 100 mL of pH 5.0 MES buffer. The carboxyl groups introduced by polyacrylic acid mainly adsorb heavy metal ions through ion exchange, and can achieve broad-spectrum and efficient adsorption in conjunction with amino sites. Furthermore, under acidic conditions, although the carboxyl groups are partially protonated, there are still a large number of carboxyl groups on the long chain of polyacrylic acid that can undergo ion exchange. Under alkaline conditions, the carboxyl groups, as negatively charged groups, can assist in electrostatic adsorption. Then add 0.5 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.2 g of N-hydroxysuccinimide, and stir for 30 min to form an activated polyacrylic acid solution for later use. Immerse the amino-modified silica aerogel described in step S1 into the activated polyacrylic acid solution, and adjust the pH to 0.4% pre-cooled sodium hydroxide solution within 1-2 min. 8.0, then placed in a 30℃ constant temperature water bath and stirred for 24h. The aerogel was taken out and thoroughly soaked and washed with deionized water for 36h, with the deionized water being replaced every 2h until the washing liquid showed no chloride ions when tested with silver nitrate and no amino byproducts when tested with ninhydrin. Finally, the washed product was soaked and replaced with anhydrous ethanol and tert-butanol three times in sequence, 2h each time, and then freeze-dried. Polyacrylic acid long chains were grafted onto the surface of amino-modified silica aerogel. The synergistic cooperation of carboxyl and amino groups provided a large number of high-affinity adsorption sites, which significantly improved the adsorption capacity. The dissociation state of the carboxyl groups on the polyacrylic acid long chains at different pH levels perfectly complemented and relayed the protonated state of the amino groups, so that at least one functional group was always in a highly efficient working state in a wide pH range, reducing the adverse effects of acid and alkaline environments on adsorption performance, and obtaining polyacrylic acid grafted amino-modified silica aerogel material.

[0070] S3. Grind the polyacrylic acid-grafted amino-modified silica aerogel material described in step S2, controlling the particle size to 300 mesh, to obtain aerogel powder for later use. Grind the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material, controlling the particle size to 300 mesh, to obtain ternary composite powder for later use. Weigh 0.5g of genipin and add it to 200mL of pH 9.0 PBS buffer, sonicate at 40℃ for 40min to form a genipin crosslinking solution for later use. Then mix the aerogel powder and the ternary composite powder and add them to 100mL of deionized water, sonicate under ice bath for 30min to form a suspension slurry for later use. Then slowly add the genipin crosslinking solution dropwise to the suspension slurry at a rate of 1 drop / second through a constant pressure dropping funnel, while stirring at 300rpm. After the addition is complete, place it in a 37℃ water bath and stir at 250rpm for 48h. Filter, and wash the filter cake repeatedly with deionized water. The product was washed until the washing liquid was colorless and clear, and then soaked in ethanol solutions with mass fractions of 30%, 50%, 70%, and 90% for 6 hours each time. Finally, it was soaked in anhydrous ethanol and tert-butanol for 6 hours. The product was then removed, freeze-dried, pre-frozen at -50℃ for 8 hours, and then dried at -60℃ and 8 Pa vacuum for 72 hours. Using polyacrylic acid-grafted amino-modified silica aerogel as a rigid framework network and reinforced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent as flexible sites, a crosslinking agent anchors and interweaves the two to form a stable, uniform, and highly interconnected three-dimensional network. It also has three powerful functional groups: carboxyl, amino, and phenolic hydroxyl. Through broad-spectrum and efficient chelation and ion exchange, it achieves ultra-high capacity adsorption of heavy metal ions and ultra-wide pH range adaptability, further enhancing the purification and adsorption effect of wastewater, and obtaining a high-performance adsorbent material for wastewater treatment.

[0071] Comparative Example 1

[0072] This comparative example provides a high-performance adsorbent material for wastewater treatment. The difference between this material and Example 1 is that the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material does not contain nanocellulose; nanocellulose is not added in step (2) of the preparation method of the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material; and the preparation method of the high-performance adsorbent material for wastewater treatment is the same as that of Example 1.

[0073] Comparative Example 2

[0074] This comparative example provides a high-performance adsorbent material for wastewater treatment. The difference between this material and Example 1 is that the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material does not contain tannin; tannin is not added in step (3) of the preparation method of the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material; and the preparation method of the high-performance adsorbent material for wastewater treatment is the same as that of Example 1.

[0075] Comparative Example 3

[0076] This comparative example provides a high-performance adsorbent material for wastewater treatment. The difference between this material and Example 1 is that the amino-modified silica aerogel material grafted with polyacrylic acid does not contain polyacrylic acid; the preparation method of the enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material is the same as that of Example 1; and polyacrylic acid is not added in step S2 of the preparation method of the high-performance adsorbent material for wastewater treatment.

[0077] Experimental Example 1

[0078] Adsorption experiment

[0079] Test samples: High-performance adsorbent materials for wastewater treatment prepared in Examples 1-4 and Comparative Examples 1-3.

[0080] Test method: A simulated wastewater with a heavy metal concentration of 100 mg / L was prepared, and the pH of the water was 5.0-8.0. In this experiment, Pb was selected. 2+ Adsorption experiments were conducted on heavy metal pollutants. 1.0 g of the test sample was weighed and added to 1000 mL of simulated wastewater. The mixture was placed in a constant-temperature shaker (303 K, 120 rpm) and reacted for 24 h. The solution was then filtered through a 0.45 μm organic filter membrane. A suitable amount of the filtrate was taken and the Pb content was determined using the dithizone spectrophotometric method. 2+ The residual concentration of Pb is specifically defined as follows: in an alkaline buffer medium (pH 9.5), the residual concentration of Pb is... 2+ The compound reacts with dithizone to form a red complex. After extraction with carbon tetrachloride, the organic phase is separated, and its absorbance is measured at 520 nm using a UV-Vis spectrophotometer. Pb is then determined according to the dithizone method. 2+ The standard curve fitting equation for concentration-absorbance is A = 0.1986C + 0.0042(R²). 2 =0.9995), thus obtaining the Pb corresponding to the absorbance of the measured solution. 2+ The mass concentration was determined, and the adsorption capacity (mg / g) of Pb²⁺ was calculated using the following formula:

[0081] Adsorption capacity (mg / g) = (C0 - C) e )×V / m

[0082] Where C0 is the initial pollutant mass concentration in mg / L, C e V represents the mass concentration of the pollutant after adsorption (mg / L), V is the solution volume (L), and m is the amount of test sample added (g).

[0083] Figure 1The figures show the adsorption results for Examples 1-4 and Comparative Examples 1-3. As shown, the adsorption capacity of Examples 1-4 was 88-95 mg / g, indicating good adsorption. The adsorption capacity of Comparative Examples 1-3 was 35-67 mg / g, indicating poor adsorption. The enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material of Comparative Example 1 lacks nanocellulose, making it impossible to block the tight packing of polysaccharide molecular chains through rigid fibers, which is detrimental to the formation of a multi-level and stable pore structure within the material, resulting in poor adsorption. The enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material of Comparative Example 2 lacks tannin, making it impossible to introduce highly active, multi-site catechol / pyrogallol structures, resulting in poor adsorption. The polyacrylic acid-grafted amino-modified silica aerogel material of Comparative Example 3 lacks polyacrylic acid, making it impossible to introduce high-capacity carboxyl adsorption sites and construct a three-dimensional adsorbent, resulting in poor adsorption.

[0084] Experimental Example 2

[0085] pH adaptation experiment

[0086] Test samples: High-performance adsorbent materials for wastewater treatment prepared in Examples 1-4 and Comparative Examples 1-3.

[0087] Test method: Simulated wastewater with pH values ​​of 3.0, 7.0, and 11.0, and a heavy metal concentration of 100 mg / L, was prepared respectively. Common heavy metals, such as Pb, were selected for this experiment. 2+ To conduct a purification experiment for heavy metal pollutants, 1.0 g of the test sample was weighed and added to 1000 mL of simulated wastewater. The sample was placed in a constant-temperature shaker (303 K, 120 rpm) and reacted for 24 h. Then, the sample was filtered through a 0.45 μm organic filter membrane. An appropriate amount of the filtrate was taken and the Pb content was determined by dithizone spectrophotometry. 2+ The residual concentration of Pb is specifically defined as follows: in an alkaline buffer medium (pH 9.5), the residual concentration of Pb is... 2+ The compound reacts with dithizone to form a red complex. After extraction with carbon tetrachloride, the organic phase is separated, and its absorbance is measured at 520 nm using a UV-Vis spectrophotometer. Pb is then determined according to the dithizone method. 2+ The standard curve fitting equation for concentration-absorbance is A = 0.1986C + 0.0042(R²). 2 =0.9995), thus obtaining the Pb corresponding to the absorbance of the measured solution. 2+ The mass concentration of Pb is obtained according to the formula in Experiment 1. 2+ Adsorption capacity Q 3.0 Q 7.0 Q 11.0 (mg / g), and then calculate the adsorption retention rate (%) according to the following formula:

[0088] Adsorption retention rate (%) = (QpH3.0 Or Q pH11.0 ) / Q pH7.0 ×100%

[0089] Figure 2 The graph shows the adsorption retention rates of Examples 1-4 and Comparative Examples 1-3. As shown, Examples 1-4 exhibited adsorption retention rates of 83-90% and 88-95% at pH 3.0 and pH 11.0, respectively, indicating a wide pH adaptability and good adsorption under acidic and alkaline conditions. Comparative Examples 1-3 showed adsorption retention rates of 47-75% and 39-80% at pH 3.0 and pH 11.0, respectively, indicating moderate or poor pH adaptability and moderate or poor adsorption under acidic and alkaline conditions. The enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material of Comparative Example 1 lacks nanocellulose and cannot form a nanoscale rigid network framework. Under extreme pH conditions, it cannot prevent excessive swelling and collapse of chitosan and deacetylated konjac glucomannan, which is detrimental to the material's adsorption under relatively low pH conditions. The lack of intact morphology and adsorption performance over a wide pH range results in poor pH adaptability and poor adsorption under acidic and alkaline conditions. The enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent material in Comparative Example 2 lacks tannins, hindering the synergistic complementarity between the low-protonated tannin phenolic hydroxyl groups and chitosan, thus limiting its adsorption performance across acidic and alkaline pH environments and resulting in only moderate pH adaptability and adsorption under acidic and alkaline conditions. The polyacrylic acid-grafted amino-modified silica aerogel material in Comparative Example 3 lacks polyacrylic acid. Over a wide pH range, it cannot utilize the dissociation states of the carboxyl groups on the long polyacrylic acid chain at different pH levels, thus failing to ensure that at least one carboxyl or amino functional group is always in a highly efficient working state, leading to poor pH adaptability and poor adsorption under acidic and alkaline conditions.

[0090] The above experimental results show that the adsorption capacity and pH adaptability of Examples 1-4 of the present invention are significantly better than those of Comparative Examples 1-3. Among them, Example 1, which uses an enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent and a polyacrylic acid-grafted amino-modified silica aerogel, has a stronger adsorption capacity and a wider pH adaptability. The enhanced tannin-grafted deacetylated konjac glucomannan ternary composite adsorbent and the polyacrylic acid-grafted amino-modified silica aerogel form a stable, uniform, and highly interconnected three-dimensional network under cross-linking. It is rich in three powerful functional groups: carboxyl, amino, and phenolic hydroxyl groups. Through broad-spectrum and efficient chelation and ion exchange, it achieves ultra-high capacity adsorption of heavy metal ions and ultra-wide pH adaptability, significantly enhancing adsorption performance and optimizing the treatment effect of wastewater purification.

[0091] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

[0092] The present invention and its embodiments have been described above. This description is not restrictive, and the accompanying drawings are only one embodiment of the present invention. The actual application is not limited to this. In conclusion, if those skilled in the art are inspired by this description and design similar methods and embodiments without departing from the spirit of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A high performance adsorbent material for sewage treatment, characterized by: The sewage treatment high-performance adsorption material comprises the following components in parts by weight: 20-40 parts of reinforced tannin grafted deacetylated konjac glucomannan ternary composite adsorption material, 10-20 parts of polyacrylic acid grafted amino modified silica aerogel material, and 3-5 parts of genipin.

2. A method of preparing a high performance adsorbent material for wastewater treatment according to claim 1, characterized by: Specifically comprising the following steps: S1, 25 mL of tetraethyl orthosilicate is added to 40 mL of anhydrous ethanol and stirred uniformly, a 0.1 mol / L hydrochloric acid standard solution is used to adjust the pH to 3.0-4.0, and magnetic stirring is carried out at 50-60°C for 1-2 h, and then the mixture is cooled to room temperature and left to stand for 2-4 h, the formed gel is aged at room temperature for 24 h, then anhydrous ethanol is added and the aging is continued in a 40°C water bath for 24 h, the wet gel is taken out, and solvent exchange is carried out with anhydrous ethanol and n-hexane for 36-48 h, the solvent is replaced every 6 h, the wet gel after the solvent exchange treatment is freeze-dried to obtain the silica aerogel, 3-aminopropyltriethoxysilane is added to 500 mL of anhydrous ethanol which has been dried by 3A molecular sieves, and stirring is carried out at room temperature for 10-15 min to form a modified solution, the silica aerogel is soaked in the modified solution, and refluxing is carried out at 70-80°C for 8-12 h under the protection of nitrogen, after the reaction is completed, the product is washed with anhydrous ethanol for 3-5 times, and finally vacuum drying is carried out at 60-80°C to obtain the amino modified silica aerogel; S2, polyacrylic acid with a molecular weight of 5000 is added to 100 mL of MES buffer solution with a pH of 4.5-5.0, then 0.3-0.5 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and 0.1-0.2 g of N-hydroxysuccinimide are added, and stirring is carried out for 20-30 min to form an activated polyacrylic acid solution, the amino modified silica aerogel prepared in step S1 is immersed in the activated polyacrylic acid solution, a 0.4% pre-cooled sodium hydroxide solution is used to adjust the pH to 7.5-8.0 within 1-2 min, and then the mixture is placed in a thermostatic water bath at 25-30°C and stirred for 12-24 h, the aerogel is taken out and washed with deionized water for 24-36 h, the deionized water is replaced every 2 h, until the washing liquid is detected to be free of chloride ions by silver nitrate detection and free of amino by ninhydrin detection, and finally the product after washing is immersed in anhydrous ethanol and tert-butanol for 2-3 times, each time for 2 h, and freeze-drying is carried out to obtain the polyacrylic acid grafted amino modified silica aerogel material; S3, grinding the polyacrylic acid grafted amino-modified silica aerogel material of step S2, controlling the particle size to be 100-300 mesh, to obtain an aerogel powder for standby use, grinding the enhanced tannin grafted deacetylated konjac glucomannan ternary composite adsorption material, controlling the particle size to be 100-300 mesh, to obtain a ternary composite powder for standby use, taking 0.3-0.5 g of genipin and adding it into 200 mL of PBS buffer solution with pH of 8.0-9.0, ultrasonic treatment at 40 ℃ for 30-40 min to form a genipin crosslinking solution for standby use, then mixing the aerogel powder and the ternary composite powder and adding them into 100 mL of deionized water, ultrasonic dispersion under ice bath for 20-30 min to form a suspension slurry for standby use, then slowly adding the genipin crosslinking solution into the suspension slurry through a constant pressure dropping funnel at a speed of 1-2 drops per second, while stirring at a speed of 200-300 rpm, after the addition is completed, placing it in a 37 ℃ water bath and stirring at a speed of 200-250 rpm for 24-48 h, suction filtration, washing the filter cake with deionized water repeatedly until the washing liquid is colorless and clear, then sequentially immersing it in ethanol solutions with mass fractions of 30%, 50%, 70% and 90% for 4-6 h each time, finally immersing it in anhydrous ethanol and tert-butyl alcohol for 4-6 h, taking out the product, freeze-drying, pre-freezing at -50 ℃ for 6-8 h, then drying at -60 ℃ and a vacuum degree of 6-8 Pa for 48-72 h, to obtain a high-performance adsorption material for sewage treatment.

3. The method for preparing high-performance adsorbent material for wastewater treatment according to claim 2, characterized in that: In step S1, the addition amount of 3-aminopropyl triethoxysilane is 18-24 mL.

4. The method for preparing high-performance adsorbent material for wastewater treatment according to claim 3, characterized in that: In step S2, the addition amount of polyacrylic acid is 0.8-1.0 g.

5. The method for preparing high-performance adsorbent material for wastewater treatment according to claim 4, characterized in that: The preparation method of the enhanced tannin grafted deacetylated konjac glucomannan ternary composite adsorption material specifically includes the following steps: (1) dispersing konjac glucomannan in 500 mL of an ethanol solution with a mass fraction of 40%, stirring and heating to 40-50 ℃, then adding 8.0-10.0 g of anhydrous sodium carbonate and continuing to stir for 1-2 h, placing it at room temperature to cool, filtering, transferring the solid product to a beaker, dispersing it in 100 mL of distilled water, adding 0.1 mol / L hydrochloric acid standard solution drop by drop under stirring for neutralization, until the pH of the suspension is 6.5-7.5, filtering, washing the precipitate with an ethanol solution with a mass fraction of 30% for 3-5 times, and finally washing it with distilled water for 3-5 times, 100 ℃ vacuum drying, to obtain deacetylated konjac glucomannan; (2) The dried nanocellulose is added to 50 mL of distilled water, first stirred by magnetic force for 10-20 min, then treated by ice-bath ultrasonic for 10-20 min, ultrasonic power 250-300 W, ultrasonic 2 s, interval 1 s, to form nanocellulose dispersion liquid for use. 0.8-1.0 g of chitosan powder with deacetylation degree ≥90% is weighed and added to 100 mL of 1% acetic acid aqueous solution, stirred in a 40-50°C water bath for 1-2 h to form a chitosan acetic acid solution for use. Then 200 mL of distilled water is added to a three-necked flask, stirred at a speed of 200-250 rpm, first add the nanocellulose dispersion liquid, keep the stirring speed unchanged, and slowly add the chitosan acetic acid solution at a speed of 1-2 drops per second using a constant pressure dropping funnel, after the addition is completed, continue to stir for 30-40 min, then add the deacetylated konjac glucomannan described in step (1), add distilled water to make the reaction system reach 300 mL, and stir at room temperature for 1-2 h to obtain a composite base slurry; (3) Ascorbic acid and tannin are added to the composite base slurry described in step (2), stirred at a speed of 200-250 rpm under a nitrogen protective atmosphere for 20-30 min, then 30 mL of 3.4% hydrogen peroxide solution is added, and reacted at 25°C for 8-9 h. After filtration, the solid is first soaked and washed with 100 mL of 0.4% sodium hydroxide solution for 2-3 times, each time stirred for 5 min and then filtered, then soaked and washed with 100 mL of 50°C 1% sodium dodecyl sulfate aqueous solution for 2-3 times, each time stirred for 10 min and then filtered, and finally washed with distilled water for 3-5 times. The solid product is dried at 60°C under vacuum to obtain an enhanced tannin grafted deacetylated konjac glucomannan ternary composite adsorption material.

6. The method for preparing high-performance adsorbent material for wastewater treatment according to claim 5, characterized in that: In step (1), the addition amount of konjac glucomannan is 8.0-10.0 g.

7. The method for preparing high-performance adsorbent material for wastewater treatment according to claim 6, characterized in that: In step (2), the addition amount of nanocellulose is 1.0-1.5 g.

8. The method for preparing high-performance adsorbent material for wastewater treatment according to claim 7, characterized in that: In step (3), the addition amounts of ascorbic acid and tannin are 0.5-1.0 g and 2.0-3.0 g, respectively.

Images