Functionalized knitted fabric containing carboxyl and amino as well as preparation method and application of functional knitted fabric

Abstract

The invention discloses functional knitted fabric containing carboxyl and amino and a preparation method and application, and belongs to the technical field of functional materials.The preparation method comprises the following steps that acrylic knitted fabric serves as a raw material, cyano on the surface of acrylic and triethylene tetramine are subjected to an addition reaction, amino is grafted to an acrylic matrix, and multi-amino knitted fabric is prepared; amino on the multi-amino knitted fabric and iminodiacetic acid or chloroacetic acid are subjected to carboxylation reaction to generate the functional knitted fabric containing carboxyl and amino. According to the preparation method, an amination and carboxylation two-step method is adopted, amido and carboxyl are grafted to acrylic knitted fabric in sequence, and the carboxyl functionalized knitted fabric is prepared in situ for the first time. The method has the advantages that the advantages of high adsorption sensitivity, deformation resistance and the like of acrylic fiber knitted fabric are organically combined with selective adsorption of carboxyl functional groups on alkaline pollution gas, strength damage and form loss caused when acrylic fibers are directly used for preparing carboxyl fibers are avoided, and material support is provided for application in the aspect of large-air-volume low-concentration ammonia gas purification.

Description

Technical Field

[0001] The invention relates to the technical field of functional materials, and in particular to a functionalized knitted fabric containing carboxyl groups and amino groups for purifying aquaculture waste gas, and a preparation method and application thereof. Background Art

[0002] NH3 is one of the eight malodorous pollutants published in my country's "Emission Standards for Malodorous Pollutants" (GB14554-93). It is also the malodorous gas with the highest concentration and the most harmful to humans and animals among the malodorous gases emitted by animal husbandry. It is produced by urease decomposing organic nitrogen in animal feces under suitable conditions. NH3 is a colorless alkaline gas with a pungent odor. Its chemical properties are active. It not only pollutes the air, destroys the ecological structure and biodiversity, but also seriously damages human skin tissue and respiratory system. The degree of harm is related to the duration and concentration of the malodor. The most harmful and wide-ranging malodor exposure is low-concentration and long-term malodor exposure.

[0003] At present, the methods for treating NH3 at home and abroad mainly include: (1) Chemical absorption-water circulation wet scrubber spray technology: Ammonia scrubber and spray tower are the most common ammonia treatment technologies at this stage. Ammonia is absorbed by dilute sulfuric acid through gas-liquid contact, and the neutralized liquid collects the by-products in the form of salt and discharges them through wastewater. Its disadvantage is that the treatment efficiency cannot directly meet the requirements of the upcoming odor pollutant emission standard (draft for comments). If the efficiency needs to be improved, the number of spray tower stages needs to be increased, which will greatly increase the treatment cost. (2) Physical absorption-absorption tower: Soft water or dilute ammonia water is used as absorbent to absorb ammonia in industrial tail gas, obtain low-concentration ammonia water and distill to obtain concentrated ammonia water; its disadvantage is that the water consumption is large, and the large amount of dilute ammonia water produced in the absorption process must be concentrated to 20% by heating, which consumes a lot of energy and has a low ammonia recovery rate. After the tail gas after water washing is recovered by membrane separation, the ammonia concentration in the gas is relatively high and must be burned to produce a certain amount of NOx, causing secondary pollution. (3) Membrane absorption: Membrane absorption technology is a new type of high-efficiency separation method with the advantages of large contact area per unit volume and non-interference between the two-phase flow. At the same time, it can avoid the shortcomings of liquid flooding, channeling and mist entrainment, thereby enhancing gas-liquid mass transfer, and has become a technology that has attracted increasing attention from researchers at home and abroad. Membrane technology is limited to treating low-concentration ammonia-containing waste gas. When the inlet flow rate increases, the purification efficiency decreases accordingly. It is not suitable for high-concentration industrial waste gas. (4) Catalytic thermal cracking-ammonia separator: This technology decomposes ammonia into nitrogen, hydrogen and nitrogen oxides at a high temperature of 1200℃, among which the proportion of nitrogen oxides is ≤0.1%. However, this method also faces many problems, such as: when the temperature exceeds 1200℃, the catalyst vapor pressure will be too high and the catalyst loss will be accelerated; when the temperature is lower than 900℃, the catalyst is prone to sulfur poisoning or ammonium salts will block the catalyst, which directly affects the service life of the catalyst. The ammonia decomposition reaction releases a large amount of heat, but it is not easy to recycle, resulting in high energy consumption and high operating costs for ammonia catalytic decomposition, which is not suitable for widespread use. (5) Biodegradation: Biological methods have inherent advantages in purifying organic pollutants, but they are mainly limited to laboratory research. There are still many shortcomings that need to be improved and overcome through theory and practice. For example, the degree of automation of the control and operation process, the strength and specific surface area of ​​the filler, the ability to handle high loads, the life of the reactor, operating costs, scrapping measures and environmental hazards are not very mature. When biodegradation treatment technology is used as an industrial method for treating ammonia-containing waste gas, the current research level on the toxicity resistance and degradation efficiency of biological strains cannot meet specific requirements. (6) Plasma technology: The specific reaction process of plasma technology used to purify toxic and harmful gases is unclear, and the cleaning and selection issues in the application have not made good progress, and more exploration and experimental verification are needed.(7) New technologies - fuel cell catalytic reaction treatment technology, etc.: At present, there are also new ammonia removal devices using fuel cell technology. This device uses stable zirconium oxide as a solid electrolyte, strontium manganate as a cathode, porous metal ceramics as an anode, and porous nickel as an integrated electrical appliance to protect the anode gas diffusion layer. This new device is highly efficient and environmentally friendly, but the cost is difficult for the market to accept at this stage.

[0004] In summary, the existing ammonia treatment technologies have various deficiencies to a certain extent. With the further improvement of the country's requirements for gaseous pollutant emissions, the deep purification of ammonia in exhaust gas has become a technical problem in the aquaculture industry, PROBAN flame-retardant fabric production industry and other industries with large air volume and low concentration of ammonia-related gas pollutant emissions, which has produced significant social and environmental benefits. In addition, the breakthrough of this type of technology can significantly enhance the visibility and influence of our institute in promoting local economic development.

[0005] Environmental functional fiber is a new type of polymer functional material with unique chemical and physical adsorption, separation, catalysis and other properties. It is called the functional material of the 21st century by the international scientific and industrial communities. It has the following advantages: (1) good mechanical properties, high adsorption rate, and good separation effect; (2) strong desorption and regeneration ability, and can maintain a good application form during repeated adsorption and desorption cycles; (3) cheap and easy to obtain raw materials; (4) with a certain elasticity and low flow resistance, it can be made into non-woven fabrics, fabrics, ion exchange columns and other forms. As one of the three major synthetic fibers, polyacrylonitrile (PAN) fiber has good mechanical strength, thermal stability and chemical stability. Its molecules contain a large number of cyano (-CN) active groups, which can react with a variety of reagents to produce modified PAN ion exchange fiber materials containing different functional groups (carboxyl, amino, sulfonic acid, thiol, etc.). PAN-based fiber materials rich in functional groups can not only be directly used for heavy metal adsorption or acid-base waste gas treatment, but also can be used as intermediate materials for the development of new ion exchange fiber materials. Among them, the process of synthesizing carboxyl functional fibers by alkaline hydrolysis of PAN has achieved industrial mass production, and alkaline gas purification devices with needle-punched cloth made of carboxyl functional fibers as the core material have been widely used in many high-concentration NH3 emission industries such as sewage treatment plants, smelting, and petrochemicals. However, in terms of treating odorous gases from aquaculture with large air volume and low concentration, gas purification devices with knitted cloth as carriers have shown limitations such as insufficient strength, large wind resistance, and obvious deformation, which restrict the treatment effect and service life of the device.

[0006] Therefore, the development of an in-situ carboxyl functionalized knitted fabric material can help to solve technical problems in industries with large air volume and low concentration of ammonia gas pollutant emissions, such as animal husbandry and PROBAN flame-retardant fabric production. Breakthroughs in this type of technology can also significantly enhance the visibility and influence of our institute in promoting local economic development. Summary of the invention

[0007] In view of this, the present invention provides a functionalized knitted fabric containing carboxyl groups and amino groups for use in the purification of aquaculture waste gas, as well as a preparation method and application, to solve the above technical problems.

[0008] In order to achieve the above technical purpose, the present invention provides a method for preparing a functional knitted fabric containing carboxyl groups and amino groups, comprising the following steps:

[0009] (1) Amination reaction: Using acrylic knitted fabric (PAN fabric) as raw material, the cyanide group on the surface of acrylic knitted fabric reacts with triethylenetetramine to graft the amine group onto the acrylic matrix to prepare polyamine knitted fabric (APAN fabric). The reaction equation is:

[0010]

[0011] (2) Carboxylation reaction: The amine groups on the polyamine knitted fabric react with iminodiacetic acid or chloroacetic acid to form functionalized knitted fabric containing carboxyl groups and amino groups. The amine groups on the polyamine knitted fabric react with chloroacetic acid to undergo an amine electrophilic substitution reaction under alkaline conditions. The amine group acts as a negative ion nucleophile to attack the carboxymethyl cation substrate in ClCH2COOH. After the reaction, Cl leaves with a lone pair of electrons and forms HCl with the H removed from the amine group, causing the reaction equilibrium to continue to move to the right, and finally forming a carboxylated functionalized knitted fabric. The reaction equation is:

[0012]

[0013] Wherein, in step (1), the bath ratio of acrylic knitted fabric to triethylenetetramine is 1:30-80, and the immersion time of acrylic knitted fabric in triethylenetetramine is 0.5-5h; the heating reaction temperature is 60-120°C, and the addition reaction time is 2-6h.

[0014] Wherein, in step (1), after the addition reaction, the steps of washing and drying are also included, and the drying temperature is 40-80°C.

[0015] Wherein, in step (2), before the carboxylation reaction, the step of soaking the polyamine-based knitted fabric in ethylene glycol for swelling is included to obtain swollen fibers.

[0016] The bath ratio of the polyamine-based knitted fabric immersed in ethylene glycol is 1:30-80, and the swelling time is 0.5-5h.

[0017] Before the carboxylation reaction, the organic acid and sodium hydroxide are dissolved in a small amount of water respectively, and then the sodium hydroxide solution is added to the organic acid solution in small amounts and multiple times, and the pH value is measured in real time until the addition is stopped at 9 to 11; during the carboxylation reaction, the sodium hydroxide solution containing the organic acid is mixed with the swollen fiber, the pH value is adjusted to 9-11, the reaction temperature is 60-120°C, and the reaction time is 4-8h.

[0018] The organic acid is chloroacetic acid, iminodiacetic acid or benzenetetracarboxylic acid, and the mass ratio of the organic acid to the acrylic knitted fabric is 1 to 2:1.

[0019] Wherein, in step (2), after the carboxylation reaction, a washing and drying step is further included, and the drying temperature is 40-80°C.

[0020] The invention also provides a functional knitted fabric containing carboxyl groups and amino groups, which is made by the above-mentioned preparation method.

[0021] The invention also provides application of functionalized knitted fabric containing carboxyl groups and amino groups in purifying aquaculture odor.

[0022] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0023] 1. The present invention adopts a two-step method of amination and carboxylation to successively graft amine groups and carboxyl groups onto acrylic knitted fabrics, and prepares carboxyl functionalized knitted fabrics in situ for the first time. Its advantage is that it organically combines the advantages of acrylic knitted fabrics such as high adsorption sensitivity and deformation resistance with the selective adsorption of alkaline polluted gases by carboxyl functional groups, avoiding the strength damage and morphological loss caused by directly preparing carboxyl fibers from acrylic fibers, and providing material support for the application of carboxyl functionalized fiber materials in the purification of high air volume and low concentration ammonia.

[0024] 2. The present invention enhances the stability of acrylic fiber through a polyamine cross-linking reaction, and the introduced polyamine functional groups undergo N-alkylation reaction with chloroacetic acid to graft carboxyl functional groups on the matrix. The destruction of the skeleton structure of the acrylic fiber matrix is ​​effectively avoided when the acrylic fiber is hydrolyzed to prepare carboxyl functional fibers, and the mechanical strength of the matrix material is retained on the basis of the introduction of carboxyl functional groups. The innovation of the preparation process broadens the industrial application field of carboxyl functional materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is an infrared spectrum diagram of the present invention for measuring and analyzing the characteristic functional groups of the knitted fabric before and after the reaction. DETAILED DESCRIPTION

[0026] The following embodiments are provided for a better understanding of the present invention, but are not limited to the best mode of implementation, and do not limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0027] Example 1

[0028] This embodiment provides a method for preparing a functionalized knitted fabric containing carboxyl groups and amino groups, comprising the following steps:

[0029] (1) Amination reaction: Immerse acrylic knitted fabric (PAN fabric) in triethylenetetramine (bath ratio: 1:50, time: 3 h), react in a round-bottom flask in an 80°C oil bath for 4 h to graft the amino group onto the fiber fabric; wash with water until neutral and then dry (drying temperature 60°C) to obtain polyamine knitted fabric (APAN fabric).

[0030] (2) Carboxylation reaction: Take polyamine knitted fabric (APAN fabric), soak it in ethylene glycol for swelling time (bath ratio: 1:50, swelling time: 4h), dissolve chloroacetic acid and sodium hydroxide in a small amount of water, add sodium hydroxide solution to the chloroacetic acid solution in small amounts and multiple times, measure the pH value in real time, and stop adding until 10 (the mass ratio of chloroacetic acid to acrylic knitted fabric is 1.5:1). Mix the solution with the swollen fiber and adjust the pH value to 10; react in a round-bottom flask at 60-120℃ oil bath for 4-8h to graft the carboxyl group to the polyamine knitted fabric (APAN fabric); wash with water to neutral after cooling, and dry (drying temperature 60℃) to obtain functional knitted fabric containing carboxyl and amino groups.

[0031] Example 2

[0032] This embodiment provides a method for preparing a functionalized knitted fabric containing carboxyl groups and amino groups, comprising the following steps:

[0033] (1) Amination reaction: Soak acrylic knitted fabric (PAN fabric) in triethylenetetramine (bath ratio: 1:30, time: 5 h), react in a round-bottom flask in a 60°C oil bath for 6 h to graft the amino group onto the fiber fabric; wash with water until neutral and then dry (drying temperature 40°C) to obtain polyamine knitted fabric (APAN fabric).

[0034] (2) Carboxylation reaction: Take polyamine knitted fabric (APAN fabric), soak it in ethylene glycol for swelling time (bath ratio: 1:30, swelling time: 5h), dissolve iminodiacetic acid and sodium hydroxide in a small amount of water respectively, add sodium hydroxide solution to the iminodiacetic acid solution in small amounts and multiple times, measure the pH value in real time, and stop adding until 9 o'clock (the mass ratio of iminodiacetic acid to acrylic knitted fabric is 1:1); react in a round-bottom flask under a 60°C oil bath for 8h to graft the carboxyl group to the polyamine knitted fabric (APAN fabric); after cooling, wash with water to neutrality and dry (drying temperature 40°C) to obtain functional knitted fabric containing carboxyl and amino groups.

[0035] Example 3

[0036] This embodiment provides a method for preparing a functionalized knitted fabric containing carboxyl groups and amino groups, comprising the following steps:

[0037] (1) Amination reaction: Soak acrylic knitted fabric (PAN fabric) in triethylenetetramine (bath ratio: 1:80, time: 0.5 h), react in a round-bottom flask in an oil bath at 120 °C for 2 h to graft the amino group onto the fiber fabric; wash with water until neutral and then dry (drying temperature 80 °C) to obtain polyamine knitted fabric (APAN fabric).

[0038] (2) Carboxylation reaction: Take polyamine knitted fabric (APAN fabric), soak it in ethylene glycol for swelling time (bath ratio: 1:80, swelling time: 0.5h), dissolve chloroacetic acid and sodium hydroxide in a small amount of water, add sodium hydroxide solution to the chloroacetic acid solution in small amounts and multiple times, measure the pH value in real time, and stop adding until 11 o'clock (the mass ratio of chloroacetic acid to acrylic knitted fabric is 2:1). Mix the solution with the swollen fiber and adjust the pH value to 9; react in a round-bottom flask under a 120℃ oil bath for 4h to graft the carboxyl group to the polyamine knitted fabric (APAN fabric); after cooling, wash with water to neutrality and dry (drying temperature 80℃) to obtain functional knitted fabric containing carboxyl and amino groups.

[0039] Example 4

[0040] This embodiment provides a method for preparing a functionalized knitted fabric containing carboxyl groups and amino groups, comprising the following steps:

[0041] (1) Amination reaction: Soak acrylic knitted fabric (PAN fabric) in triethylenetetramine (bath ratio: 1:50, time: 3h), react in a round-bottom flask in an 80℃ oil bath for 4h to graft the amino group onto the fiber fabric; wash with water until neutral and then dry (drying temperature 60℃) to obtain polyamine knitted fabric (APAN fabric).

[0042] (2) Carboxylation reaction: Take polyamine knitted fabric (APAN fabric), soak it in ethylene glycol for swelling time (bath ratio: 1:50, swelling time: 3h), dissolve chloroacetic acid and sodium hydroxide in a small amount of water, add sodium hydroxide solution to the chloroacetic acid solution in small amounts and multiple times, measure the pH value in real time, and stop adding when it reaches 9.5 (the mass ratio of chloroacetic acid to acrylic knitted fabric is 1.2:1). Mix the solution with the swollen fiber, react in a round-bottom flask in an 80℃ oil bath for 6h, and graft the carboxyl group to the polyamine knitted fabric (APAN fabric). After cooling, wash with water until neutral, and dry (drying temperature 60℃) to obtain functional knitted fabric containing carboxyl and amino groups.

[0043] Example 5

[0044] This embodiment provides a method for preparing a functionalized knitted fabric containing carboxyl groups and amino groups, comprising the following steps:

[0045] (1) Amination reaction: Soak acrylic knitted fabric (PAN fabric) in triethylenetetramine (bath ratio: 1:30, time: 5 h), react in a round-bottom flask in a 60°C oil bath for 6 h to graft the amino group onto the fiber fabric; wash with water until neutral and then dry (drying temperature 40°C) to obtain polyamine knitted fabric (APAN fabric).

[0046] (2) Carboxylation reaction: Take polyamine knitted fabric (APAN fabric), soak it in ethylene glycol for swelling time (bath ratio: 1:30, swelling time: 5h), dissolve iminodiacetic acid and sodium hydroxide in a small amount of water, add sodium hydroxide solution to the iminodiacetic acid solution in small amounts and multiple times, measure the pH value in real time, and stop adding when it reaches 10.5 (the mass ratio of iminodiacetic acid to acrylic knitted fabric is 1.8:1). Mix the solution with the swollen fiber, react in a round-bottom flask at 60℃ oil bath for 8h, so that the carboxyl group is grafted to the polyamine knitted fabric (APAN fabric). After cooling, wash with water until neutral, and dry (drying temperature 40℃) to obtain functional knitted fabric containing carboxyl and amino groups.

[0047] Example 6

[0048] This embodiment provides a method for preparing a functionalized knitted fabric containing carboxyl groups and amino groups, comprising the following steps:

[0049] (1) Amination reaction: Soak acrylic knitted fabric (PAN fabric) in triethylenetetramine (bath ratio: 1:80, time: 0.5 h), react in a round-bottom flask in an oil bath at 120 °C for 2 h to graft the amino group onto the fiber fabric; wash with water until neutral and then dry (drying temperature 80 °C) to obtain polyamine knitted fabric (APAN fabric).

[0050] (2) Carboxylation reaction: Take polyamine knitted fabric (APAN fabric), soak it in ethylene glycol for swelling time (bath ratio: 1:80, swelling time: 0.5h), dissolve chloroacetic acid or iminodiacetic acid and sodium hydroxide in a small amount of water, add sodium hydroxide solution to chloroacetic acid or iminodiacetic acid solution in small amounts and multiple times, measure the pH value in real time, and stop adding until 9-11; mix the solution with the swollen fiber, react in a round-bottom flask under a 120℃ oil bath for 4h, so that the carboxyl group is grafted to the polyamine knitted fabric (APAN fabric). After cooling, wash with water until neutral, and dry (drying temperature 80℃) to obtain functional knitted fabric containing carboxyl and amino groups.

[0051] 1. Structure and performance characterization

[0052] 1. Infrared spectrum analysis: Fourier transform infrared spectrometer was used to measure and analyze the characteristic functional groups of knitted fabrics before and after the reaction. The infrared spectrum is shown in the figure below: Figure 1 As shown, ① is acrylic knitted fabric (PAN fabric), ② is polyamine knitted fabric (APAN fabric) obtained in step (1) of Example 1; ③ is functionalized knitted fabric containing carboxyl and amino groups obtained in Example 4 (obtained by reaction with iminodiacetic acid); ④ is functionalized knitted fabric containing carboxyl and amino groups obtained in Example 1 (obtained by reaction with chloroacetic acid). Figure 1 It can be seen that the infrared spectrum ② after the amination reaction has significant changes compared with the infrared spectrum of acrylic knitted fabric ①. The characteristic absorption peak of cyano group (2242cm-1) and the absorption peak of copolymerization unit (2942cm-1, 1740cm-1, 1457cm-1, 1377cm-1, 1239cm-1, etc.) on acrylic knitted fabric are significantly weakened or disappeared, while new absorption peaks related to grafted structure (-C==NH, -C-NH-) (3443cm-1, 1664cm-1, 1610cm-1, 1122cm-1, etc.) appear, proving that after the above reaction, the chemical structure of the knitted fabric has changed significantly and new chemical groups have been introduced. Infrared spectra ③④ are the infrared spectra of the final product of APAN after carboxylation reaction of iminodiacetic acid and chloroacetic acid. The spectrum shows that the characteristic absorption peak of cyano group (2242cm -1 ) almost disappeared, indicating that almost all cyano groups participated in the reaction, 1730cm -1 Carboxyl -COOH appeared at the position of the knitted fabric, and the amine absorption peak at 1664cm-1 became wider and stronger, indicating that carboxyl -COOH and amine groups were grafted onto the knitted fabric.

[0053] 2. Tensile strength

[0054] The breaking properties of the functionalized knitted fabric fibers and acrylic knitted fabric raw materials of Examples 1-6 were tested using an electronic single fiber strength tester, with a holding distance of 10 mm and a tensile speed of 20 mm / min. The test results are shown in Table 1:

[0055] Table 1 Tensile strength test results

[0056] Breaking strength (cN / dext) Elongation at break (%) Example 1 1.64 55.9 Example 2 1.62 55.8 Example 3 1.65 54.9 Example 4 1.68 57.2 Example 5 1.69 57.1 Acrylic knitted fabric raw materials 1.65 56.7

[0057] It can be seen from the above data that there is no significant difference between the tensile strength of the functionalized knitted fabrics of Examples 1-5 and the tensile strength of the acrylic knitted fabric raw material, which indicates that the addition reaction of the present invention does not damage the fiber strength and is conducive to industrial production.

[0058] 3. Study on the adsorption performance of NH3 in aquaculture odor gas

[0059] (1) Static adsorption study: A static adsorption test was carried out using a static reactor at room temperature and pressure. The adsorption amount of the functionalized knitted fabrics prepared in Examples 1-5 was in the range of 1 to 4 mmol / g.

[0060] (2) Dynamic adsorption study: The functionalized knitted fabrics prepared in Examples 1 to 5 were selected, and the functionalized knitted fabrics were trimmed to the same size as the inner tube area of ​​the quartz column, and then laid flat in the quartz column in multiple layers. The ammonia concentration in the breeding odor was 150-300 ppm, the flow rate was 400 ml / min, and it penetrated in 20 minutes. After the adsorption was completed, the functionalized knitted fabric was taken out and desorbed and regenerated with 0.1 mol / L HCl. The ammonia concentration in the desorbed solution can be determined according to the Nessler's reagent spectrophotometric method for the determination of ammonia nitrogen in water quality (HJ 535-2009); the adsorption capacity of the functionalized knitted fabrics in each example is shown in Table 2:

[0061] Table 2 Adsorption capacity test results

[0062] <![CDATA[Adsorption capacity / (mg·g -1 ),12 h]]> <![CDATA[Adsorption capacity / (mg·g -1 ),12 h]]> Example 1 56.12 56.34 Example 2 55.34 55.89 Example 3 57.12 57.21 Example 4 56.64 57.15 Example 5 56.23 56.41

[0063] Moreover, after 50 times of adsorption and regeneration of the functionalized knitted fabric, there was no significant change in the adsorption capacity and breaking strength.

[0064] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention. The protection scope of the present invention is defined by the claims and their equivalent technical solutions.

Claims

1. A method for preparing a functionalized knitted fabric containing carboxyl and amino groups, characterized in that The steps include: (1) Amination reaction: Using acrylic knitted fabric as raw material, the cyanide group on the surface of the acrylic knitted fabric reacts with triethylenetetramine to graft the amine group onto the acrylic matrix to prepare a polyamine knitted fabric; (2) Carboxylation reaction: The amine groups on the polyamine knitted fabric undergo a carboxylation reaction with organic acids to generate functionalized knitted fabrics containing carboxyl groups and amino groups.

2. The method for preparing a functionalized knitted fabric containing carboxyl and amino groups according to claim 1, characterized in that: In step (1), the bath ratio of acrylic knitted fabric to triethylenetetramine is 1:30-80, and the immersion time of acrylic knitted fabric in triethylenetetramine is 0.5-5h; the heating reaction temperature is 60-120°C, and the addition reaction time is 2-6h.

3. The method for preparing a functionalized knitted fabric containing carboxyl and amino groups according to claim 1, characterized in that: In step (1), after the addition reaction, the process further includes washing and drying steps, and the drying temperature is 40-80°C.

4. The method for preparing a functionalized knitted fabric containing carboxyl and amino groups according to claim 1, characterized in that: In step (2), before the carboxylation reaction, the polyamine-based knitted fabric is immersed in ethylene glycol for swelling to obtain swollen fibers.

5. The method for preparing a functionalized knitted fabric containing carboxyl and amino groups according to claim 4, characterized in that: The bath ratio of the polyamine-based knitted fabric soaked in ethylene glycol is 1:30-80, and the swelling time is 0.5-5h.

6. The method for preparing a functionalized knitted fabric containing carboxyl and amino groups according to claim 4, characterized in that: Before the carboxylation reaction, the organic acid and sodium hydroxide are dissolved in a small amount of water respectively, and then the sodium hydroxide solution is added to the organic acid solution in small amounts and multiple times, and the pH value is measured in real time until the addition is stopped at 9-11; during the carboxylation reaction, the sodium hydroxide solution containing the organic acid is mixed with the swollen fiber, the pH value is adjusted to 9-11, the reaction temperature is 60-120°C, and the reaction time is 4-8h.

7. The method for preparing a functionalized knitted fabric containing carboxyl and amino groups according to claim 6, characterized in that: The organic acid is chloroacetic acid, iminodiacetic acid or benzenetetracarboxylic acid, and the mass ratio of the organic acid to the acrylic knitted fabric is 1-2:

1.

8. The method for preparing a functionalized knitted fabric containing carboxyl and amino groups according to claim 1, characterized in that: In step (2), after the carboxylation reaction, the process further includes washing and drying steps, and the drying temperature is 40-80°C.

9. A functionalized knitted fabric containing carboxyl groups and amino groups, made by the preparation method according to any one of claims 1 to 8.

10. Use of the functionalized knitted fabric containing carboxyl groups and amino groups according to claim 9 in purifying aquaculture odor.

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