Composite adsorbing material for water environment purification treatment and preparation method thereof

Abstract

The application discloses a kind of composite adsorption materials for water environment purification treatment and preparation method thereof, belong to water treatment functional material technical field.The composite adsorption material uses discarded cow hair as matrix, and the surface of matrix is formed by dopamine self-polymerization and co-deposition with metal composite powder to form polydopamine / metal composite powder coating, and polyallyl glycidyl ether is grafted on the coating by surface-initiated atom transfer radical polymerization, and finally, L-arginine or 2,4-diamino butyric acid is used for ring-opening modification.The metal composite powder is mixed by nano TiO2, nano ZrO2 and nano CeO2 in a specific ratio.The material is modified by zwitterion to give pH responsiveness, and can selectively adsorb anionic or cationic dyes under different pH conditions, and after adsorption saturation, the dyes can be eluted and recovered with dilute acid or dilute alkali, and photocatalytic regeneration can be realized by sunlight irradiation.

Description

Technical Field

[0001] This application relates to the field of water treatment functional material preparation technology, and more specifically, it relates to a composite adsorbent material for water environment purification and treatment and its preparation method. Background Technology

[0002] With the rapid development of industries such as printing and dyeing, textiles, and papermaking, large amounts of wastewater containing synthetic dyes are discharged into natural water bodies. Synthetic dyes typically possess complex aromatic ring structures and exhibit excellent chemical and photothermal stability, making them difficult to completely degrade using conventional biological or physical methods. Adsorption methods, due to their simple operation, low cost, and lack of highly toxic byproducts, have become one of the main technologies for treating dye wastewater.

[0003] Traditional adsorption materials mainly include activated carbon, silica gel, zeolite, clay minerals, and biomass materials (such as straw, fruit shells, and chitosan). Although these materials have certain adsorption capacity, they generally have the following problems: (1) poor selectivity: they lack the ability to distinguish between anionic and cationic dyes that coexist in water, making it impossible to achieve classified recycling; (2) difficult regeneration: saturated adsorbents usually require high-temperature calcination or strong acid / alkali soaking for regeneration, which consumes a lot of energy and easily damages the material structure; (3) risk of secondary pollution: adsorption only achieves phase transfer of pollutants. If saturated adsorbents are not properly treated, the adsorbed dyes will be released back into the environment; (4) waste of resources: a large amount of waste biomass (such as waste cow hair from tanneries) has not been utilized at high value, which is an environmental and resource problem faced by the tanning industry.

[0004] In recent years, researchers have attempted to endow adsorbent materials with pH responsiveness through chemical modification, such as grafting L-lysine onto a cellulose matrix. This allows for the switching adsorption of anionic and cationic dyes by utilizing the protonation / deprotonation behavior of the amino and carboxyl groups at different pH levels. However, these materials still suffer from limitations such as limited adsorption capacity, lack of in-situ regeneration capability, and restricted matrix sources. Summary of the Invention

[0005] To address the technical problems of existing adsorption materials, such as poor selectivity, difficulty in regeneration, and easy secondary pollution, this application provides a composite adsorption material for water environment purification and treatment and its preparation method.

[0006] In one aspect, this application provides a composite adsorption material for water environment purification.

[0007] A composite adsorbent material for water environment purification, wherein the composite adsorbent material uses waste cow hair as a matrix, and the surface of the matrix is ​​loaded with: a polydopamine layer formed by dopamine self-polymerization, and a metal composite powder co-deposited in the polydopamine layer; a polymer containing epoxy groups is grafted onto the polydopamine layer; the polymer is connected to an amphoteric modifier through a ring-opening reaction; the metal composite powder is composed of nano-titanium dioxide, nano-zirconium oxide and nano-cerium oxide mixed in a mass ratio of 1:(0.2-0.4):(0.1-0.2); the amphoteric modifier is L-arginine or 2,4-diaminobutyric acid.

[0008] Secondly, this application provides a method for preparing a composite adsorbent material for water environment purification.

[0009] A method for preparing a composite adsorbent material for water environment purification includes the following steps:

[0010] S1: Matrix Pretreatment

[0011] Waste cow hair is rinsed alternately with a 0.5-1.5 g / L solution of fatty alcohol polyoxyethylene ether sodium sulfate (AES) and deionized water until clean. After air drying, it is subjected to low-temperature plasma treatment: the cow hair is placed in a plasma treatment chamber, nitrogen or oxygen is introduced, and it is treated for 3-10 minutes under the conditions of 50-150 W power and 10-30 Pa vacuum to obtain activated cow hair matrix.

[0012] S2: Co-deposition of dopamine and metal composite powder

[0013] The activated bovine hair matrix was immersed in a Tris buffer solution containing dopamine and a metal composite powder. The Tris buffer solution had a pH of 7.5-8.5 and a concentration of 10-50 mmol / L; the concentration of dopamine was 0.5-2.0 g / L; and the concentration of the metal composite powder was 1.0-3.0 g / L. The reaction was carried out under light-protected conditions at 20-35°C with stirring for 12-24 hours, allowing dopamine to self-polymerize to form polydopamine and adhering and fixing the metal composite powder to the surface of the bovine hair. After the reaction was completed, the matrix was removed, rinsed with deionized water, and vacuum dried to obtain the primary complex.

[0014] S3: Surface-initiated atom transfer radical polymerization (SI-ATRP) grafting of epoxy-containing polymers.

[0015] (3.1) The primary complex obtained in step S2 was immersed in an anhydrous dichloromethane solution containing bromoisobutyryl bromide (BIBB) and triethylamine, and reacted under ice bath conditions for 2-4 h to introduce alkyl bromide initiation sites on the material surface; wherein the concentration of BIBB was 5-15 mmol / L, and the molar ratio of triethylamine to BIBB was 1.2:1. After the reaction, the mixture was washed successively with dichloromethane, ethanol, and deionized water, and then dried under vacuum to obtain the brominated complex.

[0016] (3.2) Under anhydrous and oxygen-free conditions, the brominated complex, monomer, catalyst, and ligand are added to a reaction flask. The monomer is allyl glycidyl ether (AGE), the catalyst is cuprous bromide (CuBr), and the ligand is pentamethyldiethylenetriamine (PMDETA). The molar ratio of monomer to cuprous bromide is (50-200):1, and the molar ratio of cuprous bromide to PMDETA is 1:1.2. Using N,N-dimethylformamide (DMF) or anisole as solvent, after deoxygenation of the reaction system, the reaction is stirred at 40-70℃ for 6-24h. After the reaction is completed, the material is taken out and ultrasonically washed with DMF, methanol, and deionized water in sequence to remove the physically adsorbed homopolymer. The homopolymer is then vacuum dried to obtain a complex grafted with polyallyl glycidyl ether (PAGE).

[0017] S4: Zwitterionic modification

[0018] The composite obtained in step S3 is immersed in a solution containing a zwitterionic modifier, namely L-arginine or 2,4-diaminobutyric acid, in a mixed solvent of dimethyl sulfoxide (DMSO) and water (volume ratio 4:1), with a modifier concentration of 20-50 g / L. Sodium carbonate is added as an acid-binding agent, with a molar ratio of modifier to sodium carbonate of 1:0.8-1.2. The mixture is stirred at 50-80°C for 12-24 h to allow the amino groups in the modifier to undergo a ring-opening addition reaction with the epoxy groups of the PAGE side chain. After the reaction is complete, the material is removed, washed sequentially with DMSO, ethanol, and deionized water, and then vacuum dried to obtain the composite adsorbent material.

[0019] Preferably, the preparation method of the metal composite powder is as follows: nano titanium dioxide (particle size 20-50nm), nano zirconium oxide (particle size 30-60nm), and nano cerium oxide (particle size 20-40nm) are mixed in a mass ratio of 1:0.2-0.4:0.1-0.2, added to anhydrous ethanol and ultrasonically dispersed for 30min, then the solvent is removed by rotary evaporation at 60℃, and then vacuum dried at 200-300℃ for 2h to obtain the final product.

[0020] Preferably, in step S1, the waste cow hair is raw material discarded by tanneries and is cut into 1-3cm long pieces with scissors before use.

[0021] Preferably, in step S2, the concentration of the Tris buffer is 25 mmol / L and the pH is 8.0.

[0022] Preferably, in step S3 (2), the method for removing oxygen from the reaction system is as follows: after sealing the reaction bottle, bubble it with high-purity nitrogen for 30 minutes, or perform three "vacuuming-nitrogen filling" cycles on a vacuum line.

[0023] Preferably, in step S4, after the modification reaction is completed, the agent is washed three times alternately with 0.1 mol / L hydrochloric acid solution and 0.1 mol / L sodium hydroxide solution to remove unreacted modifier and byproducts.

[0024] Preferably, the adsorption and regeneration method of the composite adsorbent material is as follows: when treating cationic dye wastewater, the pH of the wastewater is adjusted to 8-10, and adsorption is carried out in the dark for 60-120 minutes; when treating anionic dye wastewater, the pH of the wastewater is adjusted to 3-4, and adsorption is carried out in the dark for 60-120 minutes; after adsorption saturation, the material is eluted and desorbed alternately with 0.5 mol / L hydrochloric acid solution or 0.5 mol / L sodium hydroxide solution to recover the dye; the desorbed material is placed under sunlight for 1-2 hours for recycling.

[0025] In summary, this application has the following beneficial effects:

[0026] 1. This application is the first to directly use waste cow hair, after low-temperature plasma activation, as the matrix of a composite adsorbent material, without the need for dissolution or carbonization. This process fully preserves the natural scaly structure and abundant surface functional groups (-OH, -NH2, -COOH, -SH) of the cow hair. These groups can form multiple interactions with subsequent coatings, improving coating adhesion. Simultaneously, it achieves the resource utilization of leather tanning waste, aligning with the concept of a circular economy.

[0027] 2. This application employs a one-step strategy of "dopamine self-polymerization + metal composite powder co-deposition" to construct a photocatalytically active polydopamine / metal oxide composite coating on the surface of cow hair. Dopamine not only acts as a binder to firmly fix the nano-metal oxide, but its quinone / phenolic structure also promotes photogenerated electron transfer, synergistically improving photocatalytic efficiency. The metal composite powder is a ternary system of nano-TiO2, nano-ZrO2, and nano-CeO2. The addition of ZrO2 improves the thermal and chemical stability of the coating, while CeO2 enhances its oxygen storage capacity and variable valence state (CeO2). 3+ / Ce 4+ It can effectively suppress the recombination of photogenerated electron-hole pairs and significantly enhance visible light response performance.

[0028] 3. This application employs surface-initiated atom transfer radical polymerization (SI-ATRP) to graft polyallyl glycidyl ether (PAGE) onto the coating surface. Compared to the traditional "grafting to" method, this method yields a higher grafting density and a more uniform polymer layer. The epoxy groups on the PAGE side chains provide abundant reaction sites for subsequent zwitterionic modification, while the polymer's "tentacle" effect significantly increases the material's specific surface area and adsorption capacity.

[0029] 4. This application uses L-arginine or 2,4-diaminobutyric acid as modifiers, instead of the commonly used L-lysine. L-arginine's guanidinium group has a higher pKa (approximately 12.5) and stronger hydrogen bonding ability, enabling it to maintain a positive charge over a wider pH range and form stronger ion pairs and hydrogen bonds with the sulfonic acid groups in dye molecules. 2,4-diaminobutyric acid, on the other hand, has a shorter carbon chain, providing higher charge density and a faster pH response. Both modifiers impart excellent pH responsiveness to the material. By adjusting the solution pH, the surface charge of the material can be reversed, thereby selectively adsorbing anionic or cationic dyes and achieving gentle desorption and recovery of the dyes.

[0030] 5. The composite adsorbent material of this application combines the functions of high specific surface area polymer adsorption, pH-responsive selective adsorption / desorption, and sunlight photocatalytic regeneration. After adsorption saturation, no high temperature or strong chemical reagents are required; only 1-2 hours of sunlight irradiation is needed for the photocatalytic component to degrade the residual dye, achieving in-situ regeneration of the material, fundamentally avoiding secondary pollution and significantly reducing operating costs. Attached Figure Description

[0031] Figure 1 This is a flowchart illustrating the preparation process of the composite adsorbent material of this application.

[0032] Figure 2 The images shown are scanning electron microscope (SEM) images of the composite adsorbent material prepared in Example 1 of this application, where (a) is the waste cow hair matrix, (b) is the primary composite, (c) is the composite after grafting with PAGE, and (d) is the final composite adsorbent material. Detailed Implementation

[0033] The present application will be further described in detail below with reference to the embodiments.

[0034] Unless otherwise specified, the raw materials used in the embodiments and comparative examples of this application are all commercially available.

[0035] Preparation Example 1: Preparation of Metal Composite Powder

[0036] Nano-titanium dioxide (average particle size 30 nm, anatase type, purity 99.5%), nano-zirconia (average particle size 40 nm, monoclinic phase, purity 99.0%), and nano-cerium oxide (average particle size 30 nm, cubic phase, purity 99.5%) were weighed in a mass ratio of 1:0.3:0.15, totaling 50 g. These were added to 500 mL of anhydrous ethanol and ultrasonically dispersed (power 200 W, frequency 40 kHz) for 30 min. The suspension was transferred to a rotary evaporator and evaporated at a water bath of 60 °C and a vacuum of -0.09 MPa to remove the ethanol. The resulting solid powder was placed in a vacuum drying oven and dried at 250 °C and -0.1 MPa for 2 h. After grinding, it was passed through a 200-mesh sieve to obtain the metal composite powder, which was then sealed and stored in a light-proof container for later use.

[0037] Preparation Example 2: Preparation of L-arginine modified solution

[0038] Weigh 10.0 g (57.4 mmol) of L-arginine and 6.1 g (57.4 mmol) of sodium carbonate, dissolve them in a mixed solvent consisting of 160 mL of dimethyl sulfoxide (DMSO) and 40 mL of deionized water, stir until completely dissolved, and prepare a 50 g / L L-arginine modified solution (calculated as L-arginine). Seal and store for later use.

[0039] Preparation Example 3: Preparation of 2,4-Diaminobutyric Acid Modified Solution

[0040] Weigh 10.9 g (57.4 mmol) of 2,4-diaminobutyric acid dihydrochloride and 12.2 g (114.8 mmol) of sodium carbonate, dissolve them in a mixed solvent consisting of 160 mL of DMSO and 40 mL of deionized water, and stir until completely dissolved (sodium carbonate is used to neutralize the hydrochloride). Prepare a modified solution with a concentration of approximately 50 g / L based on 2,4-diaminobutyric acid, and store it in a sealed container for later use.

[0041] Example 1

[0042] A method for preparing composite adsorbent materials for water environment purification (e.g.) Figure 1 (As shown), including the following steps:

[0043] S1: Matrix Pretreatment

[0044] Take discarded white cow hair from a tannery, cut it into 2-3 cm long pieces with scissors, soak it in a 1.0 g / L sodium fatty alcohol polyoxyethylene ether sulfate (AES) solution for 30 min, then rinse it with plenty of deionized water until there is no foam in the washing liquid, rinse it three times with deionized water, and air dry it in a 40℃ oven for 24 h to obtain the cow hair matrix.

[0045] The air-dried cow hair was evenly spread on the sample stage of the plasma treatment chamber. The chamber door was closed, and the pressure was evacuated to 10 Pa. High-purity nitrogen gas was introduced to a pressure of 20 Pa, and the treatment was carried out at a radio frequency power of 100 W for 5 min. After the treatment, the cow hair was removed to obtain the activated cow hair matrix.

[0046] S2: Co-deposition of dopamine and metal composite powder

[0047] Preparation of Tris buffer: Dissolve 3.03 g of tris(hydroxymethyl)aminomethane (Tris, 25 mmol) in 800 mL of deionized water, adjust the pH to 8.0 with 0.1 mol / L hydrochloric acid, and then bring the volume to 1 L to obtain a 25 mmol / L Tris buffer solution with pH=8.0.

[0048] Weigh 1.0 g of dopamine hydrochloride and 2.0 g of the metal composite powder from Preparation Example 1, add them to 1 L of the above Tris buffer, and sonicate for 15 min to obtain a deposition solution. Immerse 10 g of the activated hair matrix obtained in step S1 into the deposition solution and react with mechanical stirring at 150 rpm for 18 h at 25 °C in the dark. After the reaction is complete, remove the hair with tweezers and wash it three times each with deionized water, anhydrous ethanol, and deionized water, and dry it in a vacuum drying oven at 50 °C for 12 h to obtain the primary complex.

[0049] S3: Surface-initiated atom transfer radical polymerization (SI-ATRP) grafted polyallyl glycidyl ether

[0050] (3.1) Introduction of initiation sites: In a 500 mL round-bottom flask, 3.0 g of the primary complex obtained in step S2 was dispersed in 200 mL of anhydrous dichloromethane, and 2.5 mL (18 mmol) of triethylamine (TEA) was added. The mixture was then cooled to 0 °C in an ice bath. Under nitrogen protection, 30 mL of anhydrous dichloromethane solution containing 2.5 mL (20 mmol) of bromoisobutyryl bromide (BIBB) was slowly added dropwise over a period of 30 min. After the addition was complete, the mixture was stirred at 0 °C for 2 h, then the ice bath was removed, and the mixture was allowed to warm naturally to room temperature and stirred for another 2 h. After the reaction was complete, the material was filtered and washed three times each with dichloromethane, anhydrous ethanol, and deionized water, and then dried under vacuum at 40 °C for 12 h to obtain the brominated complex.

[0051] (3.2) SI-ATRP polymerization: In a 250 mL Schlenk flask, 11.4 g (100 mmol) of allyl glycidyl ether (AGE) monomer, 0.143 g (1.0 mmol) of cuprous bromide (CuBr), 0.21 mL (1.0 mmol) of pentamethyldiethylenetriamine (PMDETA), and 50 mL of anisole were added as solvent. 2.0 g of the brominated composite obtained in step (3.1) was added to the flask. The Schlenk flask was sealed, and three "vacuum-nitrogen purging" cycles were performed on a vacuum line to thoroughly remove oxygen. Then, under positive nitrogen pressure, the Schlenk flask was placed in a 50 °C oil bath and magnetically stirred for 12 h. After the reaction, the Schlenk flask was opened, the material was removed, and the material was ultrasonically washed three times each with DMF, methanol, and deionized water (10 min each time) to remove physically adsorbed homopolymer. Finally, the material was vacuum dried at 40 °C for 12 h to obtain the surface-grafted PAGE composite.

[0052] S4: Zwitterionic modification

[0053] 3.0 g of the composite obtained in step S3 was immersed in 100 mL of the L-arginine modified solution from Preparation Example 2, and 0.5 g of sodium carbonate was added (to maintain an alkaline environment). The mixture was magnetically stirred in an oil bath at 65 °C for 20 h under nitrogen protection. After the reaction, the material was removed and washed three times each with DMSO, anhydrous ethanol, and deionized water. Then, it was washed three times alternately with 0.1 mol / L hydrochloric acid solution and 0.1 mol / L sodium hydroxide solution (immersion for 5 min each time), followed by washing with deionized water until neutral. Finally, it was vacuum dried at 50 °C for 24 h to obtain the composite adsorbent material.

[0054] The microstructure of the cow hair matrix, primary complex, PAGE-grafted complex, and composite adsorbent material was observed using scanning electron microscopy. The results are as follows: Figure 2 As shown. From Figure 2 As can be seen in (a), the surface of the cow hair matrix is ​​irregularly scaly; in (b), a rough coating structure is formed after the deposition of dopamine and metal composite powder; in (c), a new polymer layer appears after polymer grafting; and in (d), no obvious decomposition phenomenon is observed after L-arginine modification.

[0055] Performance testing

[0056] (1) Adsorption of cationic dye (methylene blue): 100 mL of a 350 mg / L methylene blue solution was taken, and the pH was adjusted to 9.0 with 0.1 mol / L NaOH. 1.0 g of the composite adsorbent material prepared in this example was added, and the adsorption was carried out at 150 rpm for 90 min under light-protected conditions at 25 °C. After centrifugation, the supernatant was taken and the residual concentration was determined by UV-Vis spectrophotometer (λ_max=664 nm). The adsorption rate was calculated to be 99.3%.

[0057] (2) Adsorption of anionic dye (Acid Red 18): Take 100 mL of Acid Red 18 solution with a concentration of 350 mg / L, adjust the pH to 3.5 with 0.1 mol / L HCl, add 1.0 g of composite adsorption material, and shake to adsorb for 90 min under the same conditions. The residual concentration (λ_max=506 nm) was measured and the adsorption rate was 98.7%.

[0058] (3) pH selectivity: When the pH values ​​in the above experiment were reversed (i.e., cationic dye at pH=3.5 and anionic dye at pH=9.0), the adsorption rates decreased to 4.2% and 3.1%, respectively, indicating that the composite adsorption material has excellent pH selectivity.

[0059] (4) Desorption and regeneration: Add 50 mL of 0.5 mol / L HCl solution to the saturated material (taking methylene blue as an example), shake and elute for 30 min, pour off the eluent, repeat three times, combine the eluents and determine the dye concentration. The desorption rate was 97.6%. The desorbed material was washed with deionized water until neutral, placed under sunlight (light intensity of about 80,000 lux) for 1.5 h, and used for adsorption again. After 10 cycles, the adsorption rate of methylene blue on the 10th cycle was still 93.8%.

[0060] Example 2

[0061] The difference between this embodiment and Example 1 is that: the amount of metal composite powder used in step S2 is changed to 3.0 g / L; the monomer AGE in step S3 (2) is changed to 120 mmol, and the reaction time is changed to 18 h; the modifier in step S4 is changed to 2,4-diaminobutyric acid (using the modified solution of Preparation Example 3), the reaction temperature is changed to 70 °C, and the reaction time is changed to 24 h. The remaining steps are the same.

[0062] Performance test results:

[0063] The adsorption rates were 99.1% for methylene blue (pH=9) and 99.0% for Acid Red 18 (pH=3.5); in the pH selectivity experiment, the adsorption rates were 3.8% and 2.9% under opposite pH conditions, respectively; the desorption rates were 98.2% (acid elution of cationic dyes) and 98.5% (alkali elution of anionic dyes), respectively; and the regeneration adsorption rates after 10 cycles were 94.1% and 93.7%, respectively.

[0064] Example 3

[0065] The difference between this embodiment and Example 1 is as follows: In step S1, the plasma treatment is changed to an oxygen atmosphere (high-purity oxygen is introduced), the power is 120W, and the treatment time is 8min; in step S2, the concentration of dopamine hydrochloride is changed to 1.5g / L, and the metal composite powder is changed to a mixture of nano TiO2, nano ZrO2, and nano CeO2 in a mass ratio of 1:0.4:0.1 (the preparation method is the same as in Example 1); in step S3 (2), the solvent is changed to DMF, and the reaction temperature is changed to 60℃; in step S4, the concentration of L-arginine is changed to 40g / L, the reaction temperature is changed to 75℃, and the reaction time is changed to 18h. The remaining steps are the same.

[0066] Performance test results:

[0067] The adsorption rates of methylene blue (pH=9) were 99.5% and those of Acid Red 18 (pH=3.5) were 98.9%; under opposite pH conditions, the adsorption rates were 3.5% and 2.8%, respectively; the desorption rates were 97.9% and 98.1%, respectively; and the regeneration adsorption rates after 10 cycles were 94.5% and 93.9%, respectively.

[0068] Comparative Example 1

[0069] The difference from Example 1 is that no metal composite powder is added in step S2; instead, only Tris buffer with 1.0 g / L dopamine hydrochloride is used. The remaining steps are the same.

[0070] Performance test results: The methylene blue adsorption rate was 98.8%, but after 10 cycles, the regeneration adsorption rate dropped to 35.2%, indicating that the material cannot be effectively regenerated without photocatalytic components.

[0071] Comparative Example 2

[0072] The difference from Example 1 is that in step S2, the metal composite powder is made by mixing only nano-TiO2 and nano-CeO2 at a mass ratio of 1:0.15. The remaining steps are the same.

[0073] Performance test results: The initial adsorption rate was 99.0%, and the regeneration adsorption rate dropped to 78.6% after 10 cycles, indicating that the addition of ZrO2 improved the durability and cycle stability of the coating.

[0074] Comparative Example 3

[0075] The difference from Example 1 is that the modifier in step S4 is replaced with L-lysine (preparation method is similar, concentration 50 g / L). The remaining steps are the same.

[0076] Performance test results: Methylene blue adsorption rate was 98.5%, while the pH-selective adsorption rate was 5.6% (slightly higher than the 4.2% of this application), and the regeneration adsorption rate after 10 cycles was 91.2% (lower than the 93.8% of this application). This indicates that the guanidino group of L-arginine provides stronger pH responsiveness and better cycling stability.

[0077] Comparative Example 4

[0078] The difference from Example 1 is that step S3 is omitted, and the primary complex from step S2 is directly modified with L-arginine (an attempt is made to introduce L-arginine onto the polydopamine layer). However, the adsorption rate of the modified material for the dye is only about 65%, indicating that there are severely insufficient adsorption sites without polymer.

[0079] The composite adsorbent material and its preparation method provided in this application have a wide range of raw material sources (waste cow hair is a tannery waste), and the preparation process is mild and controllable, making it easy to scale up for production. The material has a high selective adsorption capacity for both anionic and cationic dyes and can be regenerated in situ by sunlight irradiation. It is suitable for the purification and treatment of water environments such as dyeing and printing wastewater, textile wastewater, and papermaking wastewater, and can also achieve the classified recycling of dyes, resulting in significant economic and environmental benefits.

[0080] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, and such modifications are protected by patent law as long as they fall within the scope of protection claimed in this application.

Claims

1. A composite adsorbent material for water environment purification and treatment, characterized in that, The composite adsorbent material uses waste cow hair as a matrix, and the surface of the matrix is ​​loaded with: a polydopamine layer formed by dopamine self-polymerization, and a metal composite powder co-deposited in the polydopamine layer; a polymer containing epoxy groups is grafted onto the polydopamine layer; the polymer is connected to an amphoteric modifier through a ring-opening reaction; The metal composite powder is composed of nano-titanium dioxide, nano-zirconium oxide, and nano-cerium oxide mixed in a mass ratio of 1:(0.2-0.4):(0.1-0.2). The zwitterionic modifier is L-arginine or 2,4-diaminobutyric acid; The composite adsorbent material is prepared using the following steps: S1: After cleaning and air-drying the waste cow hair, it is subjected to low-temperature plasma treatment to obtain activated cow hair matrix; S2: Immerse the activated cow hair matrix in Tris buffer containing dopamine and metal composite powder, stir and react in the dark for 12-24 hours to allow dopamine to self-polymerize to form polydopamine and co-deposit and fix the metal composite powder on the surface of the cow hair. After washing and drying, the primary complex is obtained. S3: Introduce alkyl bromide initiation sites on the surface of the primary complex, and then, under anhydrous and oxygen-free conditions, use allyl glycidyl ether as a monomer and cuprous bromide / pentamethyldiethylenetriamine as a catalytic system to graft polyallyl glycidyl ether via surface-initiated atom transfer radical polymerization to obtain a polymer grafted complex. S4: Immerse the polymer grafted composite in a solution containing L-arginine or 2,4-diaminobutyric acid, and stir at 50-80℃ for 12-24 hours to allow the zwitterionic modifier to undergo a ring-opening addition reaction with the epoxy group. After washing and drying, the composite adsorbent material is obtained.

2. The composite adsorbent material for water environment purification and treatment according to claim 1, characterized in that, In step S1, the conditions for low-temperature plasma treatment are: atmosphere is nitrogen or oxygen, power is 50-150W, vacuum degree is 10-30Pa, and treatment time is 3-10min.

3. The composite adsorbent material for water environment purification and treatment according to claim 1, characterized in that, In step S2, the pH of the Tris buffer solution is 7.5-8.5 and the concentration is 10-50 mmol / L; the concentration of dopamine is 0.5-2.0 g / L and the concentration of the metal composite powder is 1.0-3.0 g / L.

4. The composite adsorbent material for water environment purification and treatment according to claim 1, characterized in that, In step S3, the specific operation of introducing the alkyl bromide initiation site is as follows: the primary complex is immersed in an anhydrous dichloromethane solution containing bromoisobutyryl bromide and triethylamine, and reacted under ice bath conditions for 2-4 hours. The concentration of bromoisobutyryl bromide is 5-15 mmol / L, and the molar ratio of triethylamine to bromoisobutyryl bromide is 1.2:

1.

5. The composite adsorbent material for water environment purification and treatment according to claim 1, characterized in that, In step S3, the reaction conditions for surface-initiated atom transfer radical polymerization are as follows: the molar ratio of allyl glycidyl ether to cuprous bromide is (50-200):1, the molar ratio of cuprous bromide to pentamethyldiethylenetriamine is 1:1.2, the reaction solvent is N,N-dimethylformamide or anisole, the reaction temperature is 40-70℃, and the reaction time is 6-24h.

6. The composite adsorbent material for water environment purification and treatment according to claim 1, characterized in that, In step S4, the solution containing the zwitterionic modifier comprises the modifier, sodium carbonate, dimethyl sulfoxide, and water, wherein the concentration of the modifier is 20-50 g / L, the molar ratio of the modifier to sodium carbonate is 1:0.8-1.2, and the volume ratio of dimethyl sulfoxide to water is 4:

1.

7. The composite adsorbent material for water environment purification and treatment according to claim 1, characterized in that, The preparation method of the metal composite powder is as follows: nano titanium dioxide, nano zirconium oxide and nano cerium oxide are mixed in a mass ratio of 1:(0.2-0.4):(0.1-0.2), anhydrous ethanol is added and ultrasonically dispersed for 30 min, then the solvent is removed by rotary evaporation at 60℃, and then vacuum dried at 200-300℃ for 2 h to obtain the final product.

8. The composite adsorbent material for water environment purification and treatment according to claim 1, characterized in that, In step S4, after the reaction is complete, the process further includes washing the sample three times alternately with 0.1 mol / L hydrochloric acid solution and 0.1 mol / L sodium hydroxide solution.

9. The composite adsorbent material for water environment purification and treatment according to claim 1, characterized in that, The composite adsorbent material can be obtained by a regeneration method, which is as follows: after adsorption saturation, the dye is recovered by alternating elution and desorption with 0.5 mol / L hydrochloric acid solution or 0.5 mol / L sodium hydroxide solution. The desorbed material is then placed under sunlight for 1-2 hours for recycling.

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