Preparation method of bovine collagen-based aerogel material adsorbing Cu(Ⅱ)

Abstract

The present invention discloses a method for preparing a bovine collagen-based aerogel material that selectively adsorbs Cu(II). The method uses bovine collagen extracted from leather solid waste as raw material, performs a molding and modification process on the material, forms a gel by means of the crosslinking effect between sodium alginate and crosslinking ions, activates the adsorbent using plasma technology, filters out excess moisture from the resulting hydrogel spheres, precools the spheres using a vacuum freeze dryer, places the hydrogel spheres in a cold trap for prefreezing, and then freeze-dries them under vacuum conditions. After drying, the bovine collagen-based aerogel material that adsorbs Cu(II) is obtained. The present invention uses bovine collagen as raw material and employs dielectric barrier discharge plasma technology and vacuum freeze-drying technology to produce a hierarchical porous structure aerogel. The aerogel can selectively treat Cu(II) in copper-containing wastewater under low-temperature conditions, has strong adsorption capacity, and can achieve a removal rate of over 90% at 30°C. It is also easy to recycle.

Description

Technical Field

[0001] The present invention belongs to the technical field of adsorption material preparation, and specifically relates to a method for preparing a cowhide collagen-based aerogel material that can efficiently and selectively adsorb Cu(II) under low-temperature conditions. This method helps solve the problem of copper pollution, thereby achieving the goal of protecting human health and environmental sustainable development. Background Art

[0002] Copper, a metal that has been vital to humanity since ancient times, is both a nutrient and a toxic element. Excessive concentrations in water can severely impact the environment and human health. The hazards of copper-containing wastewater include: 1. Environmental impacts: Copper can have devastating effects on aquatic and terrestrial environments, disrupting ecological balance; 2. Impacts on crops: Using copper-containing wastewater for irrigation not only impairs crop growth but also contaminates food, affecting its quality and safety; 3. Impacts on human health: Long-term exposure to copper-containing wastewater can cause acute or chronic poisoning, with long-term consequences for human health. Various methods are available for removing Cu(II) from water. Chemical precipitation methods, among others, produce large amounts of heavy metal sludge that requires further treatment to prevent secondary contamination. Ion exchange processes require regular regeneration and maintenance of the exchange resin to maintain its efficiency. While electrolysis can effectively remove Cu(II) from water, it consumes a high amount of energy. Therefore, adsorption methods, due to their high efficiency, low cost, ease of handling, and small footprint, have attracted extensive research.

[0003] my country's leather industry generates a significant amount of solid waste annually, containing a significant amount of collagen. Failure to fully utilize this waste will result in a waste of resources. Collagen possesses excellent adsorption properties, is recyclable, and is biodegradable, minimizing environmental impact. Therefore, applying collagen extracted from leather solid waste to adsorption applications can help conserve resources, improve economic efficiency, and reduce environmental pollution.

[0004] Collagen is rich in nitrogen- and oxygen-containing functional groups, which can serve as active sites for coordination with Cu(II), making it a good adsorption material. However, collagen is readily soluble in water, and sodium alginate can be introduced to form collagen adsorption materials through the cross-linking effect between sodium alginate and cross-linking ions. In addition, collagen and tannin extracts can form not only hydrogen bonds but also covalent bonds with the help of cross-linking agents. The abundant phenolic hydroxyl groups in tannin extracts also have excellent adsorption capacity for Cu(II). Therefore, making full use of bovine skin collagen to prepare adsorbents is a research topic worthy of attention. Summary of the Invention

[0005] This invention aims to provide a simple, low-cost method for preparing a cowhide collagen-based aerogel material that efficiently and selectively adsorbs Cu(II) at low temperatures, thereby fully utilizing the collagen extracted from leather solid waste. The aerogel can selectively treat Cu(II) in copper-containing wastewater, exhibits strong adsorption capacity, ideal material functionality, and is easily recyclable.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] The preparation method of the Cu(II)-adsorbed bovine collagen-based aerogel material is as follows:

[0008] (1) Sodium alginate was dissolved in deionized water and dispersed by alternating ultrasonic stirring;

[0009] (2) mixing bovine collagen powders of different particle sizes, pouring the mixed powder into deionized water for magnetic stirring, then pouring the mixed powder into the solution obtained in step (1), and dispersing the mixed powder by alternating ultrasonic stirring;

[0010] (3) The solution obtained in step (2) is dripped into the mixed solution of Sr(II), Fe(III) and Zr(IV) using a peristaltic pump, and magnetic stirring is performed during the dripping process. After the dripping is completed, slow stirring is performed again, and initial hydrogel spheres are formed after cross-linking;

[0011] (4) washing the hydrogel spheres obtained in step (3) with deionized water and placing them in a dielectric barrier discharge reactor for activation;

[0012] (5) Dissolve the black wattle bark tannin powder in deionized water, disperse it by ultrasonic until uniform, and collect the supernatant after standing;

[0013] (6) Pour the hydrogel spheres obtained in step (4) into the solution obtained in step (5), slowly stir and then wash;

[0014] (7) activating the hydrogel spheres obtained in step (6) again according to the method of step (4);

[0015] (8) Pour the hydrogel spheres obtained in step (7) into a mixed solution of glutaraldehyde, formaldehyde and oxazolidine, slowly stir and then wash with deionized water;

[0016] (9) Filter out excess water from the hydrogel spheres obtained in step (8), pre-cool them using a vacuum freeze dryer, place the hydrogel spheres in a cold trap for pre-freezing, and then freeze-dry them. After drying, the target product, a bovine collagen-based aerogel material with Cu(II) adsorbed, is obtained.

[0017] Furthermore, in the step (1), 0.6 to 1.0 g of sodium alginate is dissolved in 30 mL of deionized water, and ultrasonic stirring is used at pH 6 and 40° C. The ultrasound is turned off after each 10 minutes of ultrasonication, and the mixture is stirred for 5 minutes. The total ultrasonication time is 1 hour, and the mixture is dispersed until uniform and free of lumps.

[0018] Furthermore, in step (2), 0.2 to 0.4 g of bovine collagen powder with a particle size of 80 to 300 meshes is weighed and mixed, the mixed powder is poured into 10 mL of deionized water, and magnetic stirring is performed at a speed of 150 to 200 rpm and a magnetic stirring temperature of 5 to 10° C., and then poured into the solution obtained in step (1), and dispersed for 1 hour using an ultrasonic stirring alternating method.

[0019] Furthermore, in the step (3), the solution obtained in the step (2) is dripped into a mixed solution of Sr(II), Fe(III) and Zr(IV) in different proportions using a peristaltic pump. During the dripping process, the solution is stirred at a speed of 100 to 120 rpm using a magnetic stirrer. After the dripping is completed, the solution is slowly stirred at a speed of 150 to 200 rpm, and the initial hydrogel spheres are prepared after cross-linking at 25°C.

[0020] Furthermore, in step (3), the inner diameter of the silicone tube of the peristaltic pump is 1.6-3.1 mm, the flow rate of the peristaltic pump is 3.5-5.5 d / s, the ratio of Sr(II), Fe(III) and Zr(IV) in the mixed solution of Sr(II), Fe(III) and Zr(IV) is Sr(II):Fe(III):Zr(IV)=1-5:1-5:1-5, and the cross-linking time is 60-120 min.

[0021] Furthermore, the activation conditions in step (4) are as follows: under standard atmospheric pressure, oxygen is introduced into the dielectric barrier discharge reactor at a flow rate of 50 to 200 mL / min, plasma is generated by applying a voltage of 100 to 500 V and a current of 2 to 6 A, discharge activation is performed every 1 to 5 minutes, each activation lasts 10 to 50 seconds, and the activation reaction is performed for a total of 20 to 60 minutes.

[0022] Furthermore, the mass of the black wattle bark tannin powder in step (5) is 0.5 to 2.5 g.

[0023] Furthermore, in step (8), the hydrogel spheres obtained in step (7) are poured into 100 mL of a mixed solution of glutaraldehyde, formaldehyde and oxazolidine with a volume fraction of 3-5%; wherein the volume fraction ratios of glutaraldehyde, formaldehyde and oxazolidine are glutaraldehyde: formaldehyde: oxazolidine = 0-5:0-5:0-5.

[0024] Furthermore, the freeze-drying time in step (9) is 10 to 12 hours.

[0025] Furthermore, in the step (9), excess water of the hydrogel balls obtained in the step (8) is filtered out with filter paper, and the vacuum freeze dryer is first pre-cooled. After the cold trap temperature drops to -40°C, the hydrogel balls are placed in the cold trap and pre-frozen for 15 minutes, and then freeze-dried under vacuum conditions with a vacuum degree of 1 to 10 Pa. The cold trap temperature is maintained at about -60°C. After drying, the target product, bovine collagen-based aerogel material adsorbing Cu(II), is obtained.

[0026] The present invention utilizes dielectric barrier discharge plasma technology and vacuum freeze-drying technology to produce a layered porous aerogel, which exhibits excellent adsorption capacity for Cu(II) at low temperatures, achieving a removal rate exceeding 90% at 30°C. The present invention utilizes bovine skin collagen as raw material and forms a gel through the crosslinking interaction between sodium alginate and crosslinking ions. Tannin extracts are introduced through hydrogen bonding and covalent interactions, resulting in the gel containing abundant active functional groups such as hydroxyl, amino, carboxyl, and peptide groups. These functional groups interact with Cu(II) through coordination and ion exchange. Plasma technology is used to activate the adsorbent, effectively stimulating the material's groups and enhancing its functionality. The aerogel of the present invention has a layered porous structure, and its adsorption of Cu(II) is unaffected by other contaminants in the water, enabling the selective treatment of Cu(II) in copper-containing wastewater. Vacuum freeze-drying technology is used to form the material into an aerogel, making it easily recyclable. Adsorption experiments have shown that the aerogel exhibits excellent selective adsorption capacity for Cu(II) at low temperatures. Using cowhide collagen extracted from leather solid waste as raw material, it is shaped and improved to give it better adsorption properties. This is an innovative attempt to address the problem of resource waste. It not only solves the problem of resource recycling, but also solves the problem of copper pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The present invention will be described in detail below through specific examples. These examples are provided in order to enable a more thorough understanding of the present invention and to fully convey the scope of the present invention to those skilled in the art. As mentioned throughout the specification and claims, "including" or "comprising" is an open-ended term and is interpreted as "including but not limited to". The subsequent description of the specification is a preferred embodiment of the present invention, but the description is based on the general principles of the specification and is not intended to limit the scope of the present invention. The scope of protection of the present invention shall be determined by the appended claims. Unless otherwise specified, the various reagents and materials used in the present invention can be purchased from the market.

[0028] Figure 1 The actual image (a), SEM image (b), EDS image after adsorption (c), selective adsorption image (d), and hydrated ion model (illustrations in c and d) of the bovine collagen-based aerogel material of the present invention. DETAILED DESCRIPTION

[0029] Example 1

[0030] A method for preparing a cowhide collagen-based aerogel material capable of efficiently and selectively adsorbing Cu(II) under low temperature conditions comprises the following steps:

[0031] (1) Dissolve 0.6 g of sodium alginate in 30 mL of deionized water. Use ultrasonic stirring at pH 6 and 40 °C. Turn off the ultrasound after every 10 minutes and stir for 5 minutes. The total ultrasonic time is 1 hour. Disperse until uniform and free of lumps.

[0032] (2) Weigh 0.2 g of bovine collagen powder with particle sizes of 80-100, 100-200, and 200-300 mesh respectively and mix them. Pour the mixed powder into 10 mL of deionized water and stir it at 150-200 rpm with a magnetic stirrer at 10°C until it is uniform. Slowly pour it into the solution obtained in step (1) and ultrasonically stir it for 1 hour using the ultrasonic stirring alternating method in step (1);

[0033] (3) The solution obtained in step (2) was dripped into a mixed solution of Sr(Ⅱ), Fe(Ⅲ) and Zr(Ⅳ) in different proportions (Sr(Ⅱ):Fe(Ⅲ):Zr(Ⅳ)=1:1:1) using a peristaltic pump with a silicone tube with an inner diameter of 1.6 mm at a flow rate of 3.5 d / s. During the dripping process, the solution was stirred at a speed of 100-120 rpm using a magnetic stirrer. After the dripping was completed, the solution was slowly stirred at a speed of 150-200 rpm. After cross-linking at 25°C for 60 min, the initial hydrogel spheres were prepared.

[0034] (4) The hydrogel balls were washed with deionized water five times and then placed in a dielectric barrier discharge reactor for activation. Oxygen was introduced into the reactor at a flow rate of 50 mL / min under standard atmospheric pressure. Plasma was generated by applying a voltage of 100 V and a current of 2 A. Discharge activation was performed every 5 minutes, each activation lasting 10 seconds, for a total of 20 minutes of activation reaction.

[0035] (5) Weigh 0.5 g of black wattle bark tannin powder with a molecular weight of 500-3000 and dissolve it in 100 mL of deionized water. Ultrasonic dispersion was performed at 25°C until uniform. After standing for 10 min, the supernatant was collected.

[0036] (6) Pour the hydrogel spheres obtained in step (4) into the solution prepared in step (5), slowly stir at 150-200 rpm at 20°C, and wash with deionized water 5 times after 2 hours;

[0037] (7) activating the hydrogel spheres obtained in step (6) again using dielectric barrier discharge plasma technology according to the method in step (4);

[0038] (8) In a fume hood, the hydrogel spheres obtained in step (7) were poured into 100 mL of a mixed solution of 3% glutaraldehyde, formaldehyde, and oxazolidine (glutaraldehyde: formaldehyde: oxazolidine = 1:0:0), slowly stirred at 150-200 rpm at 20°C, and washed five times with deionized water after 2 h.

[0039] (9) Filter out excess water from the hydrogel spheres obtained in step (8) with filter paper, pre-cool in a vacuum freeze dryer, and place the hydrogel spheres in the cold trap after the cold trap temperature drops to -40°C for 15 minutes. Freeze-dry under vacuum conditions of 1 to 10 Pa, and maintain the cold trap temperature at around -60°C. After drying for 10 hours, obtain aerogel spheres.

[0040] Example 2

[0041] A method for preparing a cowhide collagen-based aerogel material capable of efficiently and selectively adsorbing Cu(II) under low temperature conditions comprises the following steps:

[0042] (1) Dissolve 0.7 g of sodium alginate in 30 mL of deionized water. Use ultrasonic stirring at pH 6 and 40 °C. Turn off the ultrasound after every 10 minutes and stir for 5 minutes. The total ultrasonic time is 1 hour. Disperse until uniform and free of lumps.

[0043] (2) Weigh 0.3, 0.2, and 0.2 g of bovine collagen powder with a particle size of 80-100, 100-200, and 200-300 mesh, respectively, and mix them. Pour the mixed powder into 10 mL of deionized water, stir it at 150-200 rpm with a magnetic stirrer at 10°C until it is uniform, and slowly pour it into the solution obtained in step (1). Use the ultrasonic stirring alternating method in step (1) to sonicate for 1 hour;

[0044] (3) The solution obtained in step (2) was dripped into a mixed solution of Sr(II), Fe(III) and Zr(IV) in different proportions (Sr(II):Fe(III):Zr(IV)=2:1:1) using a peristaltic pump with a silicone tube with an inner diameter of 1.6 mm at a flow rate of 3.5 d / s. During the dripping process, the solution was stirred at a speed of 100-120 rpm using a magnetic stirrer. After the dripping was completed, the solution was slowly stirred at a speed of 150-200 rpm. After cross-linking at 25°C for 60 min, the initial hydrogel spheres were prepared.

[0045] (4) The hydrogel balls were washed with deionized water five times and then placed in a dielectric barrier discharge reactor for activation. Oxygen was introduced into the reactor at a flow rate of 100 mL / min under standard atmospheric pressure. Plasma was generated by applying a voltage of 200 V and a current of 3 A. Discharge activation was performed every 5 minutes, each activation lasting 20 seconds, for a total of 30 minutes of activation reaction.

[0046] (5) Weigh 1.0 g of black wattle bark tannin powder with a molecular weight of 500-3000 and dissolve it in 100 mL of deionized water. Ultrasonic dispersion was performed at 25°C until uniform. After standing for 10 min, the supernatant was collected.

[0047] (6) Pour the hydrogel spheres obtained in step (4) into the solution prepared in step (5), slowly stir at 150-200 rpm at 20°C, and wash with deionized water 5 times after 2 hours;

[0048] (7) activating the hydrogel spheres obtained in step (6) again using dielectric barrier discharge plasma technology according to the method in step (4);

[0049] (8) In a fume hood, pour the hydrogel spheres obtained in step (7) into 100 mL of a mixed solution of 3% glutaraldehyde, formaldehyde, and oxazolidine (glutaraldehyde: formaldehyde: oxazolidine = 0:1:0), slowly stir at 150-200 rpm at 20°C, and wash with deionized water five times after 2 h.

[0050] (9) Filter out excess water from the hydrogel spheres obtained in step (8) with filter paper, pre-cool in a vacuum freeze dryer, and place the hydrogel spheres in the cold trap after the cold trap temperature drops to -40°C for 15 minutes. Freeze-dry under vacuum conditions of 1 to 10 Pa, and maintain the cold trap temperature at around -60°C. After drying for 10 hours, obtain aerogel spheres.

[0051] Example 3

[0052] A method for preparing a cowhide collagen-based aerogel material capable of efficiently and selectively adsorbing Cu(II) under low temperature conditions comprises the following steps:

[0053] (1) Dissolve 0.8 g of sodium alginate in 30 mL of deionized water. Use ultrasonic stirring at pH 6 and 40 °C. Turn off the ultrasound after every 10 minutes and stir for 5 minutes. The total ultrasonic time is 1 hour. Disperse until uniform and free of lumps.

[0054] (2) Weigh 0.3, 0.3, and 0.2 g of bovine collagen powder with particle sizes of 80-100, 100-200, and 200-300 mesh, respectively, and mix them. Pour the mixed powder into 10 mL of deionized water, stir it at 150-200 rpm with a magnetic stirrer at 10°C until it is uniform, and slowly pour it into the solution obtained in step (1). Use the ultrasonic stirring alternating method in step (1) to sonicate for 1 hour;

[0055] (3) The solution obtained in step (2) was dripped into a mixed solution of Sr(II), Fe(III) and Zr(IV) in different proportions (Sr(II):Fe(III):Zr(IV)=1:2:1) using a peristaltic pump with a silicone tube with an inner diameter of 2.4 mm at a flow rate of 4.5 d / s. During the dripping process, the solution was stirred at a speed of 100-120 rpm using a magnetic stirrer. After the dripping was completed, the solution was slowly stirred at a speed of 150-200 rpm. After cross-linking at 25°C for 90 min, the initial hydrogel spheres were prepared.

[0056] (4) The hydrogel balls were washed with deionized water five times and then placed in a dielectric barrier discharge reactor for activation. Oxygen was introduced into the reactor at a flow rate of 150 mL / min under standard atmospheric pressure. Plasma was generated by applying a voltage of 300 V and a current of 4 A. Discharge activation was performed every 5 minutes, each activation lasting 30 seconds, for a total of 40 minutes of activation reaction.

[0057] (5) Weigh 1.5 g of black wattle bark tannin powder with a molecular weight of 500-3000 and dissolve it in 100 mL of deionized water. Ultrasonic dispersion was performed at 25°C until uniform. The mixture was allowed to stand for 10 min and the supernatant was collected.

[0058] (6) Pour the hydrogel spheres obtained in step (4) into the solution prepared in step (5), slowly stir at 150-200 rpm at 20°C, and wash with deionized water 5 times after 2 hours;

[0059] (7) activating the hydrogel spheres obtained in step (6) again using dielectric barrier discharge plasma technology according to the method in step (4);

[0060] (8) In a fume hood, pour the hydrogel spheres obtained in step (7) into 100 mL of a mixed solution of 3% glutaraldehyde, formaldehyde, and oxazolidine (glutaraldehyde: formaldehyde: oxazolidine = 0:0:1), slowly stir at 150-200 rpm at 20°C, and wash with deionized water five times after 2 h.

[0061] (9) Use filter paper to filter out excess water from the hydrogel spheres obtained in step (8), and pre-cool them in a vacuum freeze dryer. After the cold trap temperature drops to -40°C, place the hydrogel spheres in the cold trap and pre-freeze them for 15 minutes. Then, freeze-dry them under vacuum conditions with a vacuum degree of 1 to 10 Pa, and keep the cold trap temperature at around -60°C. After drying for 11 hours, aerogel spheres are obtained.

[0062] Example 4

[0063] A method for preparing a cowhide collagen-based aerogel material capable of efficiently and selectively adsorbing Cu(II) under low temperature conditions comprises the following steps:

[0064] (1) Dissolve 0.9 g of sodium alginate in 30 mL of deionized water. Use ultrasonic stirring at pH 6 and 40 °C. Turn off the ultrasound after every 10 minutes and stir for 5 minutes. The total ultrasonic time is 1 hour. Disperse until uniform and free of lumps.

[0065] (2) Weigh 0.4, 0.2, and 0.2 g of bovine collagen powder with particle sizes of 80-100, 100-200, and 200-300 mesh, respectively, and mix them. Pour the mixed powder into 10 mL of deionized water, stir it at 150-200 rpm with a magnetic stirrer at 10°C until it is uniform, and slowly pour it into the solution obtained in step (1). Use the ultrasonic stirring alternating method in (1) to sonicate for 1 hour;

[0066] (3) The solution obtained in step (2) was dripped into a mixed solution of Sr(II), Fe(III) and Zr(IV) in different proportions (Sr(II):Fe(III):Zr(IV)=1:1:2) using a peristaltic pump with a silicone tube with an inner diameter of 2.4 mm at a flow rate of 4.5 d / s. During the dripping process, the solution was stirred at a speed of 100-120 rpm using a magnetic stirrer. After the dripping was completed, the solution was slowly stirred at a speed of 150-200 rpm. After cross-linking at 25°C for 90 min, the initial hydrogel spheres were prepared.

[0067] (4) The hydrogel balls were washed with deionized water five times and then placed in a dielectric barrier discharge reactor for activation. Oxygen was introduced into the reactor at a flow rate of 200 mL / min under standard atmospheric pressure. Plasma was generated by applying a voltage of 400 V and a current of 5 A. Discharge activation was performed every 5 minutes, each activation lasting 40 seconds, for a total of 50 minutes of activation reaction.

[0068] (5) Weigh 2.0 g of black wattle bark tannin powder with a molecular weight of 500-3000 and dissolve it in 100 mL of deionized water. Ultrasonic dispersion was performed at 25°C until uniform. The mixture was allowed to stand for 10 min and the supernatant was collected.

[0069] (6) Pour the hydrogel spheres obtained in step (4) into the solution prepared in step (5), slowly stir at 150-200 rpm at 20°C, and wash with deionized water 5 times after 2 hours;

[0070] (7) activating the hydrogel spheres obtained in step (6) again using dielectric barrier discharge plasma technology according to the method in step (4);

[0071] (8) In a fume hood, pour the hydrogel spheres obtained in step (7) into 100 mL of a mixed solution of 3% glutaraldehyde, formaldehyde, and oxazolidine (glutaraldehyde: formaldehyde: oxazolidine = 1:1:0), slowly stir at 150-200 rpm at 20°C, and wash with deionized water five times after 2 h.

[0072] (9) Use filter paper to filter out excess water from the hydrogel spheres obtained in step (8), and pre-cool them in a vacuum freeze dryer. After the cold trap temperature drops to -40°C, place the hydrogel spheres in the cold trap and pre-freeze them for 15 minutes. Then, freeze-dry them under vacuum conditions with a vacuum degree of 1 to 10 Pa, and keep the cold trap temperature at around -60°C. After drying for 11 hours, aerogel spheres are obtained.

[0073] Example 5

[0074] A method for preparing a cowhide collagen-based aerogel material capable of efficiently and selectively adsorbing Cu(II) under low temperature conditions comprises the following steps:

[0075] (1) Dissolve 1.0 g of sodium alginate in 30 mL of deionized water. Use ultrasonic stirring at pH 6 and 40 °C. Turn off the ultrasound after every 10 minutes and stir for 5 minutes. The total ultrasonic time is 1 hour. Disperse until uniform and free of lumps.

[0076] (2) Weigh 0.4, 0.4, and 0.2 g of bovine collagen powder with particle sizes of 80-100, 100-200, and 200-300 mesh, respectively, and mix them. Pour the mixed powder into 10 mL of deionized water, stir it at 150-200 rpm with a magnetic stirrer at 10°C until it is uniform, and slowly pour it into the solution obtained in step (1). Use the ultrasonic stirring alternating method in step (1) to sonicate for 1 hour;

[0077] (3) The solution obtained in step (2) was dripped into a mixed solution of Sr(II), Fe(III) and Zr(IV) in different proportions (Sr(II):Fe(III):Zr(IV)=1:1:2) using a peristaltic pump with a silicone tube with an inner diameter of 3.1 mm at a flow rate of 5.5 d / s. During the dripping process, the solution was stirred at a speed of 100-120 rpm using a magnetic stirrer. After the dripping was completed, the solution was slowly stirred at a speed of 150-200 rpm. After cross-linking at 25°C for 120 min, the initial hydrogel spheres were prepared.

[0078] (4) The hydrogel balls were washed with deionized water five times and then placed in a dielectric barrier discharge reactor for activation. Oxygen was introduced into the reactor at a flow rate of 200 mL / min under standard atmospheric pressure. Plasma was generated by applying a voltage of 500 V and a current of 6 A. Discharge activation was performed every 5 minutes, each activation lasting 50 seconds, for a total of 60 minutes of activation reaction.

[0079] (5) Weigh 2.5 g of black wattle bark tannin powder with a molecular weight of 500-3000 and dissolve it in 100 mL of deionized water. Ultrasonic dispersion was performed at 25°C until uniform. After standing for 10 min, the supernatant was collected.

[0080] (6) Pour the hydrogel spheres obtained in step (4) into the solution prepared in step (5), slowly stir at 150-200 rpm at 20°C, and wash with deionized water 5 times after 2 hours;

[0081] (7) activating the hydrogel spheres obtained in step (6) again using dielectric barrier discharge plasma technology according to the method in step (4);

[0082] (8) In a fume hood, pour the hydrogel spheres obtained in step (7) into 100 mL of a mixed solution of 3% glutaraldehyde, formaldehyde, and oxazolidine (glutaraldehyde: formaldehyde: oxazolidine = 1:1:1), slowly stir at 150-200 rpm at 20°C, and wash with deionized water five times after 2 h.

[0083] (9) Filter out excess water from the hydrogel spheres obtained in step (8) with filter paper, pre-cool in a vacuum freeze dryer, and place the hydrogel spheres in the cold trap after the cold trap temperature drops to -40°C for 15 minutes. Freeze-dry under vacuum conditions of 1 to 10 Pa, and maintain the cold trap temperature at around -60°C. After drying for 12 hours, obtain aerogel spheres.

[0084] Experimental results

[0085] After comparing the adsorption properties of the aerogel materials prepared in Examples 1 to 5, it was found that the aerogel prepared under the experimental conditions in Example 3 (see the actual figure) Figure 1 a) has the best adsorption effect. Its SEM picture is as follows Figure 1 As shown in Figure b, it can be clearly seen that the aerogel material contains a layered porous structure, which creates a good condition for the adsorption of Cu(II). The aerogel prepared in Example 3 has a Cu(II) removal rate of more than 90%. The EDS diagram after adsorption is shown in Figure 2. Figure 1 As shown in c. Figure 1As can be seen from Figure d, compared with Pb(Ⅱ), Cr(Ⅲ), Zn(Ⅱ) and Mn(Ⅱ), the aerogel material has excellent selective adsorption capacity for Cu(Ⅱ). Figure 1 As shown in the insets in c and d, Pb(II), Cr(III), Zn(II), and Mn(II) exist in an octahedral configuration in aqueous solution, while Cu(II) exists as a square, planar hydrated copper ion. Therefore, in addition to being able to diffuse to the external surface, the planar hydrated copper ion is more likely to diffuse into the pores and react with the inner surfaces of the pores than the other four ions.

[0086] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the scope of protection of the present invention.

Claims

1. A method for preparing a Cu(II)-adsorbed bovine collagen-based aerogel material, characterized in that: The specific implementation steps are as follows: (1) Sodium alginate was dissolved in deionized water and dispersed by alternating ultrasonic stirring; (2) mixing bovine collagen powders of different particle sizes, pouring the mixed powder into deionized water for magnetic stirring, then pouring the mixed powder into the solution obtained in step (1), and dispersing the mixed powder by alternating ultrasonic stirring; (3) The solution obtained in step (2) is dripped into the mixed solution of Sr(II), Fe(III) and Zr(IV) using a peristaltic pump, and magnetic stirring is performed during the dripping process. After the dripping is completed, slow stirring is performed again, and initial hydrogel spheres are formed after cross-linking; (4) washing the hydrogel spheres obtained in step (3) with deionized water and placing them in a dielectric barrier discharge reactor for activation; (5) Dissolve the black wattle bark tannin powder in deionized water, disperse it by ultrasonic until uniform, and collect the supernatant after standing; (6) Pour the hydrogel spheres obtained in step (4) into the solution obtained in step (5), slowly stir and then wash; (7) activating the hydrogel spheres obtained in step (6) again according to the method of step (4); (8) Pour the hydrogel spheres obtained in step (7) into a mixed solution of glutaraldehyde, formaldehyde and oxazolidine, slowly stir and then wash with deionized water; (9) Filter out excess water from the hydrogel spheres obtained in step (8), pre-cool them using a vacuum freeze dryer, place the hydrogel spheres in a cold trap for pre-freezing, and then freeze-dry them. After drying, the target product, a bovine collagen-based aerogel material with Cu(II) adsorbed, is obtained.

2. The method for preparing the Cu(II)-adsorbed bovine collagen-based aerogel material according to claim 1, characterized in that: In the step (1), 0.6-1.0 g of sodium alginate is dissolved in 30 mL of deionized water, and ultrasonic stirring is used at pH 6 and 40° C. After each ultrasonic treatment for 10 minutes, the sodium alginate is turned off and stirred for 5 minutes. The total ultrasonic treatment time is 1 hour, and the sodium alginate is dispersed until it is uniform and free of lumps.

3. The method for preparing the Cu(II)-adsorbed bovine collagen-based aerogel material according to claim 2, characterized in that: In the step (2), 0.2 g of bovine collagen powder with particle sizes of 80-100, 100-200, and 200-300 meshes are weighed and mixed respectively, and the mixed powder is poured into 10 mL of deionized water, and magnetic stirring is performed at a speed of 150-200 rpm and a magnetic stirring temperature of 5-10° C., and then poured into the solution obtained in the step (1), and dispersed for 1 hour by an ultrasonic stirring alternating method.

4. The method for preparing the Cu(II)-adsorbed bovine collagen-based aerogel material according to claim 3, characterized in that: In the step (3), the solution obtained in the step (2) is dripped into a mixed solution of Sr(II), Fe(III) and Zr(IV) in different proportions using a peristaltic pump. During the dripping process, the solution is stirred at a speed of 100 to 120 rpm using a magnetic stirrer. After the dripping is completed, the solution is slowly stirred at a speed of 150 to 200 rpm. After cross-linking at 25°C, the initial hydrogel spheres are formed.

5. The method for preparing the Cu(II)-adsorbed bovine collagen-based aerogel material according to claim 4, characterized in that: In the step (3), the inner diameter of the silicone tube of the peristaltic pump is 1.6 to 3.1 mm, the flow rate of the peristaltic pump is 3.5 to 5.5 d / s, the ratio of Sr(II), Fe(III) and Zr(IV) in the mixed solution of Sr(II), Fe(III) and Zr(IV) is Sr(II):Fe(III):Zr(IV)=1 to 5:1 to 5:1 to 5, and the crosslinking time is 60 to 120 min.

6. The method for preparing the Cu(II)-adsorbed bovine collagen-based aerogel material according to claim 5, characterized in that: The activation conditions in step (4) are as follows: under standard atmospheric pressure, oxygen is introduced into the dielectric barrier discharge reactor at a flow rate of 50 to 200 mL / min, plasma is generated by applying a voltage of 100 to 500 V and a current of 2 to 6 A, discharge activation is performed every 1 to 5 minutes, each activation lasts 10 to 50 seconds, and the activation reaction is carried out for a total of 20 to 60 minutes.

7. The method for preparing the Cu(II)-adsorbed bovine collagen-based aerogel material according to claim 6, characterized in that: The mass of the black wattle bark tannin powder in step (5) is 0.5 to 2.5 g.

8. The method for preparing the Cu(II)-adsorbed bovine collagen-based aerogel material according to claim 7, characterized in that: In the step (8), the hydrogel spheres obtained in the step (7) are poured into 100 mL of a mixed solution of glutaraldehyde, formaldehyde and oxazolidine with a volume fraction of 3-5%; wherein the volume fraction ratios of glutaraldehyde, formaldehyde and oxazolidine are glutaraldehyde:formaldehyde:oxazolidine=0-5:0-5:0-5.

9. The method for preparing the Cu(II)-adsorbed bovine collagen-based aerogel material according to claim 8, characterized in that: The freeze-drying time in step (9) is 10 to 12 hours.

10. The method for preparing the Cu(II)-adsorbed bovine collagen-based aerogel material according to any one of claims 1 to 9, characterized in that: In the step (9), excess water of the hydrogel balls obtained in the step (8) is filtered out with filter paper, and the vacuum freeze dryer is first pre-cooled. After the cold trap temperature drops to -40°C, the hydrogel balls are placed in the cold trap and pre-frozen for 15 minutes. Then, freeze-drying is performed under vacuum conditions with a vacuum degree of 1 to 10 Pa, and the cold trap temperature is maintained at about -60°C. After drying, the target product, a bovine collagen-based aerogel material adsorbing Cu(II), is obtained.

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