Waste nitrogen-containing cotton-based carbon material ozone catalyst as well as preparation method and application thereof
By preparing a carbon material ozone catalyst with an asymmetric N-coordinated Fe single-atom structure, the problems of nitrogen-containing textile recycling and textile dyeing wastewater treatment were solved, realizing the efficient recycling of waste textiles and the recycling of wastewater, and promoting the sustainable development of the textile industry.
Patent Information
- Application Number
- CN202511633128.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-07
- Publication Date
- 2026-02-24
AI Technical Summary
Existing technologies are insufficient for efficiently separating and recycling nitrogen-containing fiber blended fabrics, and textile dyeing wastewater is difficult to treat, resulting in low treatment efficiency of waste textiles and textile dyeing wastewater, which poses environmental risks.
Using waste nitrogen-containing cotton textiles as raw materials, carbon material ozone catalysts with asymmetric N-coordinated Fe single-atom structures were prepared by ferric nitrate activation. These catalysts were used to simultaneously remove electron-donating and electron-withdrawing pollutants, and the treated wastewater was reused in textile printing and dyeing.
It has achieved efficient recycling of nitrogen-containing waste textiles and deep treatment of textile dyeing and printing wastewater, forming a closed-loop pollution control system and enhancing the sustainable development capability of the textile industry.
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Figure CN121554081A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of waste cotton recycling technology, specifically to an ozone catalyst based on nitrogen-containing cotton from waste cotton, its preparation method, and its application. Background Technology
[0002] As a major textile producer globally, my country is experiencing a surge in waste textile production as people's living standards improve, leading to increasingly severe textile solid waste pollution. Statistics show that my country's annual per capita fiber consumption is approximately 22.4 kg, generating about 26 million tons of waste textiles annually, with a cumulative stock of nearly 100 million tons, yet the recycling rate is less than 1%. Currently, most waste textiles in China are still disposed of through traditional incineration and landfill methods, posing potential secondary ecological and environmental risks. While recycling technologies for waste textiles such as cotton, protein fibers (wool and silk), and polyester are relatively mature, they require fibers with low impurities and high purity. However, common blended fabrics (excluding polyester-cotton blends) often contain nitrogen-containing fibers such as spandex, acrylic, and nylon. The recycling and reuse of these waste textiles requires highly sophisticated fiber separation technologies, often proving difficult to achieve effectively. Therefore, alternative high-value utilization methods need to be developed, representing a significant challenge for the waste textile recycling industry. Furthermore, a large amount of textile dyeing and printing wastewater is also generated alongside waste textiles.
[0003] Given the dual challenges of low recycling efficiency of nitrogen-containing multi-component waste textiles and the difficulty of deep treatment of textile dyeing and printing wastewater, how to efficiently and simultaneously solve the problems of nitrogen-containing waste textiles and textile dyeing and printing wastewater is a major challenge. Summary of the Invention
[0004] This invention provides an ozone catalyst based on nitrogen-containing waste cotton and its preparation method and application. Using nitrogen-containing waste cotton textiles as raw material and activated with ferric nitrate, this invention prepares an ozone catalyst based on nitrogen-containing waste cotton and carbon. This catalyst is rich in asymmetric N-coordinated Fe single-atom structures, enabling the simultaneous removal of both electron-donating and electron-withdrawing pollutants. Furthermore, the treated textile dyeing wastewater can be reused in textile dyeing. The ozone catalyst based on nitrogen-containing waste cotton and carbon obtained by this invention can solve two major challenges currently facing the recycling of nitrogen-containing waste textiles and the treatment of textile dyeing wastewater.
[0005] To achieve the above objectives, the present invention provides the following technical solution: This invention provides a method for preparing a waste nitrogen-containing cotton-based carbon material ozone catalyst, comprising: activating and carbonizing waste nitrogen-containing cotton-based fabric pretreated with ferric nitrate at 600~1000℃ for 2~3 h under an inert atmosphere, followed by post-treatment to obtain the waste nitrogen-containing cotton-based carbon material ozone catalyst; wherein the waste nitrogen-containing cotton-based fabric comprises cotton and nitrogen-containing fibers, and the nitrogen content in the nitrogen-containing fibers is 5~10 wt% based on the mass of the waste nitrogen-containing cotton-based fabric.
[0006] This invention uses ferric nitrate metal salt as a precursor to enhance the porous structure of the carbon substrate, thereby strengthening catalytic mass transfer. Simultaneously, it embeds metal active sites to enhance catalytic degradation efficiency. By utilizing nitrogen (N) elements from common mixed components in waste textiles, such as spandex, nylon, and acrylic fibers, the electron distribution of the carbon-based structure is modulated, and Fe elements are coordinated and anchored. Through optimized preparation processes, an asymmetric N-coordinated Fe single-atom structure is constructed to obtain a highly efficient ozone catalyst. Ultimately, the generated asymmetric N-coordinated Fe single-atom structure can simultaneously and efficiently treat both electron-withdrawing and electron-donating organic pollutants.
[0007] The obtained catalyst can simultaneously remove electron-donating pollutant p-aminophenol and electron-withdrawing pollutant p-nitrophenol. Furthermore, wastewater treated by the ozone catalyst from spent nitrogen-containing cotton-based carbon materials can be reused in textile printing and dyeing, achieving a closed-loop sustainable development model for pollution control in the textile industry.
[0008] Preferably, the inert atmosphere is nitrogen and / or argon.
[0009] Preferably, waste nitrogen-containing cotton fabric and ferric nitrate are mixed in water and soaked for at least 24 hours, and then dried to obtain the waste nitrogen-containing cotton fabric pretreated with ferric nitrate.
[0010] Preferably, the mass ratio of the waste nitrogen-containing cotton base fabric to the ferric nitrate is (50~200):1; and / or, the nitrogen-containing fiber is at least one of spandex, nylon, and acrylic.
[0011] Preferably, the mass ratio of the waste nitrogen-containing cotton base fabric to the ferric nitrate is (80~120):1.
[0012] Preferably, by weight, the waste nitrogen-containing cotton-based fabric comprises 60-70 parts cotton and 30-40 parts nitrogen-containing fiber.
[0013] Preferably, by weight, the waste nitrogen-containing cotton-based fabric comprises 60-70 parts cotton, 25-30 parts acrylic and 8-10 parts spandex.
[0014] Preferably, by weight, the waste nitrogen-containing cotton-based fabric comprises 60-65 parts cotton, 20-25 parts nylon and 15-25 parts acrylic.
[0015] Sufficient nitrogen (N) is required to establish an asymmetric N-coordinated Fe single-atom structure that can efficiently treat both electron-withdrawing and electron-donating organic pollutants. However, insufficient N content will result in an inadequate asymmetric N-coordinated Fe single-atom structure, which will hinder multi-component degradation treatment.
[0016] Preferably, the temperature is increased to 600-1000℃ at a heating rate of 5-10℃ / min.
[0017] Preferably, the temperature is increased to 700-900°C at a heating rate of 5-10°C / min.
[0018] Preferably, the post-treatment is as follows: after activation and carbonization, the material is washed with water at 95~100℃ and then dried to obtain the waste nitrogen-containing cotton-based carbon material ozone catalyst.
[0019] The present invention also provides an ozone catalyst made from waste nitrogen-containing cotton-based carbon materials, wherein the waste nitrogen-containing cotton-based carbon material ozone catalyst contains an asymmetric N-coordinated Fe single-atom structure.
[0020] Application of waste nitrogen-containing cotton-based carbon material ozone catalyst in ozone catalytic degradation of electron-donating and / or electron-withdrawing pollutants.
[0021] Preferably, the electron-donating pollutant is p-aminophenol, and the electron-withdrawing pollutant is p-nitrophenol.
[0022] p-Aminophenol and p-nitrophenol are both common organic pollutants in the secondary effluent of dyeing and printing wastewater. Therefore, the present invention has the following beneficial effects: (1) The waste nitrogen-containing cotton-based carbon material ozone catalyst provided by the present invention utilizes the N element in the waste cotton to modulate the electronic distribution of the carbon-based structure, and uses iron nitrate metal salt to enhance the porous structure of the carbon substrate and embed metal active sites to form an asymmetric N-coordinated Fe single-atom structure.
[0023] (2) The waste nitrogen-containing cotton-based carbon material ozone catalyst provided by the present invention can simultaneously remove electron-donating group pollutant p-nitrophenol and electron-withdrawing group pollutant p-aminophenol, thus solving the problem of needing to select a specific catalyst when degrading pollutants.
[0024] (3) The wastewater treated by the ozone catalyst of the waste nitrogen-containing cotton-based carbon material of the present invention can also be reused for textile printing and dyeing, realizing a sustainable development model of closed-loop pollution control in the textile industry. Attached Figure Description
[0025] Figure 1 This is a schematic diagram of the asymmetric single-atom structure of Fe.
[0026] Figure 2EEM spectra of dyeing and printing wastewater degradation are shown, where a is the effluent from the secondary sedimentation tank of a dyeing and printing enterprise in Hangzhou before treatment, b is the effluent from the secondary sedimentation tank of a dyeing and printing enterprise in Hangzhou after 60 min of treatment, c is the effluent from the secondary sedimentation tank of a dyeing and printing enterprise in Huzhou before treatment, and d is the effluent from the secondary sedimentation tank of a dyeing and printing enterprise in Huzhou after 60 min of treatment. Figure 3 This is a schematic diagram of the dyeing process. Figure 4 This is the absorbance curve of the dye. Detailed Implementation
[0027] The present invention will be further described below with reference to specific embodiments. Those skilled in the art will be able to implement the present invention based on these descriptions. Furthermore, the embodiments of the present invention described below are generally only some, not all, of the embodiments of the present invention. Therefore, all other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.
[0028] The raw materials used in this section are sourced as follows: Jingren Red K-3BE, Jingren Yellow K-3RE, Jingren Blue K-BF, sodium sulfate, soda ash, and leveling agent were all purchased from Zhejiang Daneng Textile Printing and Dyeing Co., Ltd. Ferric nitrate nonahydrate, cobalt nitrate hexahydrate, p-nitrophenol, and p-aminophenol were all purchased from Aladdin Reagent Co., Ltd. Sodium thiosulfate pentahydrate was purchased from Hangzhou Gaojing Fine Chemical Co., Ltd.
[0029]
Example
[0030] Under a nitrogen atmosphere, the pretreated waste cotton fabric was calcined at 800℃ with a heating rate of 10℃ / min. After holding at this temperature for 3 hours, it was naturally cooled to room temperature. The carbonized waste cotton fabric was then removed and repeatedly washed with boiling (approximately 100℃) distilled water until the washing liquid became colorless and transparent. Subsequently, it was dried at 80℃ for 12 hours and ground into powder using a mortar to obtain a nitrogen-containing waste cotton-based carbon material ozone catalyst.
[0031] Examples 1-2 (N content in the fabric is 5-10 wt%) and Comparative Examples 1-3 and Comparative Example 6, using the scheme provided in Example 1, replace the waste cotton fabric in Table 1, and keep other conditions unchanged to obtain the corresponding waste nitrogen-containing cotton-based carbon material ozone catalyst.
[0032] Table 1 Composition of Waste Cotton Fabric
[0033] Example 3 This embodiment is basically the same as embodiment 1, except that the mass ratio of ferric nitrate to waste cotton fabric in ferric nitrate nonahydrate is 1:50.
[0034] Example 4 This embodiment is basically the same as embodiment 1, except that the mass ratio of ferric nitrate to waste cotton fabric in ferric nitrate nonahydrate is 1:200.
[0035] Example 5 This embodiment is basically the same as Embodiment 1, except that the calcination temperature is 600℃.
[0036] Example 6 This embodiment is basically the same as Embodiment 1, except that the calcination temperature is 1000℃.
[0037] Comparative Example 4 This comparative example is basically the same as Example 1, except that ferric nitrate nonahydrate is not added.
[0038] Comparative Example 5 This comparative example is basically the same as Example 1, except that: ferric nitrate nonahydrate is replaced with cobalt nitrate hexahydrate, and the mass ratio of cobalt nitrate to waste cotton fabric in cobalt nitrate hexahydrate is maintained at 1:100.
[0039] [Performance Testing] 1. Catalytic degradation Test method: Prepare a 50 mg / L p-nitrophenol solution (or a 50 mg / L p-aminophenol solution, or a 1:1 (mass ratio) mixture of 50 mg / L p-nitrophenol and 50 mg / L p-aminophenol), and take 1 mL as the initial sample before each test. Then, transfer 300 mL of the solution to a 500 mL wide-mouth bottle and accurately weigh 30 mg of catalyst into it. Sonicate for 30 seconds to ensure uniform dispersion of the catalyst in the solution. To ensure stable experimental conditions, adjust the water bath temperature to 25°C and set the rotation speed to 30 r / min. Place the solution in the water bath, and after the temperature stabilizes, begin the experiment. Ozone is introduced through an ozone generator (set to a flow rate of 30 mL / min and a current of 100 mA), and timing begins immediately, continuing degradation for 15 min. At 2, 4, 6, 8, 10, and 15 minutes into the reaction, 1 mL samples were taken using a water syringe filter consisting of 0.45 μm and 0.22 μm filters (0.45 μm filter on top, 0.22 μm filter on the bottom), filtered, and allowed to stand. In addition, to comprehensively evaluate the impact of different conditions on the degradation effect, blank control experiments were set up: Blank 1 was the control without ozone introduction, and Blank 2 was the control without catalyst addition. During the experiment, sodium thiosulfate pentahydrate (30 μL) was used to quench residual ozone and other reactive oxygen species (ROS) in the samples to eliminate their potential lasting impact on the experimental results. Each experiment was repeated twice to ensure data reliability. Finally, high-performance liquid chromatography (HPLC) was used to determine the concentration of p-nitrophenol / p-aminophenol in the solution to accurately evaluate its degradation effect.
[0040] The catalysts obtained in Examples 1-6 and Comparative Examples 1-6 were tested according to the above test method to determine their ozone catalytic degradation ability and calculated according to the following formulas (1) and (2). The results are shown in Tables 2-4.
[0041] (1) (2) In the formula, C t Ct is the concentration of the p-nitrophenol (and / or p-aminophenol) solution at time t, in mg / L; C0 is the initial concentration of the p-nitrophenol (and / or p-aminophenol) solution, in mg / L; At t denoted as , where is the peak area of the characteristic peak of the p-nitrophenol (and / or p-aminophenol) solution at time t; A0 is the initial characteristic peak area of p-nitrophenol (and / or p-aminophenol); R is the degradation rate of p-nitrophenol (and / or p-aminophenol) at time t.
[0042] Table 2 Ozone catalytic degradation performance (p-nitrophenol)
[0043] Table 2 illustrates the degradation process of the electron-withdrawing organic pollutant p-nitrophenol using different systems. From the data in Table 2, we can observe that the carbon material catalyst prepared in Example 1 achieved an adsorption capacity of 15% for p-nitrophenol after 10 minutes. Data from Blank 2 shows that ozone alone is insufficient for removing p-nitrophenol, with a removal rate of only 76% after 10 minutes. The degradation rate of p-nitrophenol is significantly improved in the presence of a catalyst, with the catalyst prepared in Example 1 exhibiting the best catalytic degradation efficiency. Comparative Example 6, due to its low nitrogen-containing fiber component and low N content, cannot provide sufficient anchoring sites for Fe to form asymmetric iron metal active centers, resulting in less strongly oxidizing ROS generated by ozone activation, and a significantly lower final degradation efficiency. Example 2 shows a slightly lower degradation efficiency compared to Example 1 because the black dye present in the black waste textiles competes with organic pollutants for ROS on the catalyst surface, leading to a decrease in pollutant removal efficiency.
[0044] During the preparation process, the ratio of waste cotton fabric to ferric nitrate affects the form of iron sites. Excessive ferric nitrate content makes it difficult to form single-atom Fe sites, while insufficient ferric nitrate content fails to form enough metal active sites. Comparing the degradation data from Examples 1 and 3 / 4, it was found that a 100:1 ratio yielded the best catalytic degradation efficiency. During calcination, the Fe element in the ferric nitrate was more effectively captured and anchored by the N element, thus forming Fe-N. x Single-atom configuration active sites. Simultaneously, controlling the calcination temperature is crucial. Too low a calcination temperature not only fails to improve the graphitization degree of waste fabrics but also makes it difficult to form asymmetric N coordination sites; while too high a calcination temperature easily leads to the loss of N elements at anchored Fe sites, preventing the formation of the target asymmetric coordination configuration Fe single-atom structure. Comparing the degradation data from Examples 1 and 5 / 6, it was found that a calcination temperature of 800 °C yielded the optimal degradation performance. Although the catalysts prepared at feed ratios of 50:1 and 200:1 and calcination temperatures of 600 °C and 1000 °C showed slightly reduced catalytic efficiency, they still maintained excellent p-nitrophenol removal performance, proving that 600–1000 °C is a suitable calcination temperature.
[0045] In the absence of nitrogen in waste textiles (Comparative Examples 1-3), it is difficult for iron to be anchored in the catalyst structure. Therefore, the removal efficiency of p-nitrophenol is comparable to that of the catalyst without added iron nitrate (Comparative Example 4).
[0046] The degradation data from Comparative Example 5 show that although the Co metal sites exhibit strong catalytic activity, the Fe... 3+ It has strong Lewis acidity, which can provide more empty d orbitals to coordinate with the lone pair electrons of N element, making it easier to anchor and form a stable Fe-N. x The asymmetric single-atom coordination configuration is present. Therefore, although Comparative Example 5 exhibits good catalytic degradation efficiency, it is lower than that of Example 1.
[0047] Table 3 Ozone catalytic degradation performance (p-aminophenol)
[0048] Table 3 shows the degradation process of the electron-donating organic pollutant p-aminophenol in different systems. From the data in Table 3, it can be observed that the efficiency of each system in degrading p-aminophenol is basically consistent with that in degrading p-nitrophenol. Furthermore, Examples 1-6 also maintain excellent removal efficiency for the electron-donating organic pollutant p-aminophenol.
[0049] Table 4 Ozone catalytic degradation performance (p-nitrophenol and p-aminophenol)
[0050] Table 4 shows the degradation rates of electron-donating and electron-withdrawing organic pollutants (p-aminophenol) at 10 min in different systems. The data in Table 4 indicate that Example 1 can maintain efficient degradation of both organic pollutants simultaneously. Due to the differences in the properties of electron-donating and electron-withdrawing organic pollutants, they compete during degradation, causing the catalyst to show a stronger preference for one type of organic pollutant, often making it difficult to achieve efficient simultaneous degradation of both. Furthermore, Comparative Examples 1-3, lacking nitrogen, cannot form Fe-N. x The single-atom configuration of the active site resulted in a significant decrease in the degradation rates of both p-nitrophenol and p-aminophenol during co-treatment compared to single treatment. Comparative Example 4 also failed to form Fe-N due to the lack of Fe. x Single-atom active sites also cannot maintain the efficient simultaneous processing of p-nitrophenol and p-aminophenol. Furthermore, Co, being an active metal, can form Co-N... x The site can be identified, and the degradation effect on p-aminophenol can be better in the mixed treatment, but it still cannot efficiently degrade p-nitrophenol at the same time.
[0051] 2. Reuse of dyeing and printing wastewater Test method: The test subjects were the effluent from the secondary sedimentation tank of a printing and dyeing enterprise in Hangzhou and the effluent from the secondary sedimentation tank of a printing and dyeing enterprise in Huzhou.
[0052] Before each test, 5 mL was taken as an initial sample. Then, 300 mL of the solution was transferred to a 500 mL wide-mouth bottle, and 30 mg of the catalyst from Example 1 was accurately weighed and added. The solution was ultrasonically treated for 30 seconds to ensure uniform dispersion of the catalyst. To ensure stable experimental conditions, the water bath temperature was adjusted to 25°C, and the rotation speed was set to 30 r / min. The solution was placed in the water bath, and the experiment began after the temperature stabilized. Ozone was introduced through an ozone generator (set to a flow rate of 30 mL / min and a current of 100 mA), and timing was started immediately, continuing degradation for 60 min. At 60 min of reaction, 5 mL samples were taken from each of the 0.45 μm and 0.22 μm filter tips (0.45 μm filter tip on top, 0.22 μm filter tip on the bottom), filtered, and allowed to stand. EEM spectroscopy was then used to analyze the organic matter composition and residual pollutants in the dyeing and printing wastewater.
[0053] The EEM spectra of the secondary sedimentation tank effluent from a printing and dyeing enterprise in Hangzhou and a printing and dyeing enterprise in Huzhou before and after treatment using the above testing method are shown in [reference needed]. Figure 2 .
[0054] Figure 2 Three-dimensional fluorescence spectra of the degradation process of dyeing and printing wastewater from two different sources are shown. The upper image shows the effluent from the secondary sedimentation tank of a dyeing and printing enterprise in Hangzhou, and the lower image shows the effluent from the secondary sedimentation tank of a dyeing and printing enterprise in Huzhou. Figure 2 a and Figure 2 c describes the state of the sample before the reaction, while Figure 2 b and Figure 2 d reflects the result after 60 minutes of reaction.
[0055] Through detailed analysis Figure 2 a, Figure 2 The EEM spectral characteristic regions in section c can identify the types and relative concentrations of pollutants in the wastewater. Specifically, region I (λex / λem in the range of 200-250 nm / 280-380 nm) represents aromatic proteins, while region II (λex / λem in the range of 200-250 nm / 380-550 nm) points to fumaric acid-like compounds. Regions III (λex / λem above 250 nm and below 380 nm) and IV (λex / λem both above 280 nm and 380 nm) correspond to soluble microbial byproducts and humic acid-like organic matter, respectively. Comparing the two types of wastewater, we observed that the main pollutants in the dyeing and printing wastewater from a dyeing and printing enterprise in Hangzhou were soluble microbial byproducts and humic acid-like organic matter, while the wastewater from a dyeing and printing enterprise in Huzhou, although mainly composed of soluble microbial byproducts, also showed significant presence of pollutants in other regions, indicating a relatively rich overall pollutant content. Further observation... Figure 2 b、 Figure 2 d. After 60 minutes of intensive treatment, most of the pollutant molecules in these two types of dyeing and printing wastewater were effectively oxidized and degraded into smaller molecules, making them difficult to detect in fluorescence spectroscopy. This result demonstrates that the catalyst in Example 1 exhibits excellent efficiency in catalyzing the degradation of dyeing and printing wastewater by ozone, providing great potential for the practical application of HCO3- technology.
[0056] Subsequently, using the staining prescription in Table 5, Figure 3 The process shown involves wastewater reuse for dyeing. The fabric used is knitted cotton (5 cm × 20 cm, 2.25 g). The dyes used are: Kyonin Red K-3BE, Kyonin Yellow K-3RE, and Kyonin Blue K-BF.
[0057] Soap washing prescription: 2 g / L soap flakes; liquor ratio 1:20; temperature: 98℃; time: 10 min.
[0058] Table 5 Reactive dyeing formulas for cotton
[0059] The staining results are shown in Tables 6-7 and Figure 4 As shown in Table 6, the dye uptake and dry rubbing color fastness of dyeing with tap water and recycled water are compared for three different dye concentrations. From the data in Table 6, we can observe that the dye uptake is slightly lower with recycled water compared to tap water, but the dry rubbing color fastness is comparable. This indicates that the dyeing performance of the dye using recycled water is very similar to that using tap water. Therefore, recycled water after deep treatment of dyeing wastewater using carbon material catalysts derived from waste cotton fabrics with ozone shows good applicability in textile dyeing and printing processes.
[0060] Table 6 Dye uptake and color fastness to dry rubbing
[0061] Table 7 shows detailed tests of color characteristic values using a colorimeter, covering indicators such as L (lightness), a (red-green value), b (yellow-blue value), c (chroma value), DE (color difference), and K / S (color depth) under the CIE model. Analysis of the data in Table 7 revealed that the color difference of red dye was significantly greater than that of yellow and blue dyes at all three concentrations. However, the color difference value of blue dye was significantly lower than that of the other two colors. Further observation showed that the trend of color difference variation exhibited a similar pattern to that of dyeing rate, i.e., the color difference gradually decreased with increasing dye concentration. Based on this finding, it can be inferred that recycled water is more suitable for use with yellow and blue dyes than red dyes, and that the resulting color difference decreases accordingly with increasing dye concentration.
[0062] Table 7 Color characteristic values of dyed fabrics
[0063] Figure 4 This paper presents absorbance curves of three reactive dyes—Kyōnin Red K-3BE, Kyōnin Yellow K-3RE, and Kyōnin Blue K-BF—at a 0.1% concentration, obtained using a UV-Vis spectrophotometer in full-spectrum testing mode. These curves are primarily used to analyze the specific impact of deeply treated recycled water on the absorbance properties of the dyes. Figure 4 It can be clearly observed that the maximum absorption peaks of red, yellow, and blue dyes are located at 542 nm, 423 nm, and 613 nm, respectively. Further comparison of the absorbance curves of fabrics treated with recycled water and tap water reveals almost no significant difference between the two, either in the position of the maximum absorption peaks or the overall trend of the absorbance curves. This result indicates that dyeing with recycled water is virtually indistinguishable from dyeing with tap water in terms of the absorbance properties of the dyes, thus reflecting that recycled water has a similar dyeing effect to tap water during the dyeing process.
Claims
1. A method for preparing an ozone catalyst from waste nitrogen-containing cotton-based carbon materials, characterized in that, include: Under an inert atmosphere, waste nitrogen-containing cotton-based fabric pretreated with ferric nitrate was activated and carbonized at 600~1000℃ for 2~3 h, and then post-treated to obtain waste nitrogen-containing cotton-based carbon material ozone catalyst. The waste nitrogen-containing cotton base fabric includes cotton and nitrogen-containing fibers; based on the mass of the waste nitrogen-containing cotton base fabric, the nitrogen content in the nitrogen-containing fibers is 5~10 wt%.
2. The preparation method according to claim 1, characterized in that, The inert atmosphere is nitrogen and / or argon.
3. The preparation method according to claim 1, characterized in that, Waste nitrogen-containing cotton fabric and ferric nitrate are mixed in water and soaked for at least 24 hours, and then dried to obtain the waste nitrogen-containing cotton fabric pretreated with ferric nitrate.
4. The preparation method according to claim 3, characterized in that, The mass ratio of the waste nitrogen-containing cotton base fabric to the ferric nitrate is (50~200):1; And / or, the nitrogen-containing fiber is at least one of spandex, nylon, and acrylic.
5. The preparation method according to claim 1, 3, or 4, characterized in that, By weight, the waste nitrogen-containing cotton-based fabric comprises 60-70 parts cotton and 30-40 parts nitrogen-containing fiber.
6. The preparation method according to claim 1, characterized in that, The temperature is increased to 600-1000℃ at a heating rate of 5-10℃ / min.
7. The preparation method according to claim 1, characterized in that, The post-processing is as follows: after activation and carbonization, the material is washed with water at 95~100℃ and then dried to obtain the waste nitrogen-containing cotton-based carbon material ozone catalyst.
8. The ozone catalyst made from waste nitrogen-containing cotton-based carbon materials prepared by the preparation method according to any one of claims 1 to 7, characterized in that, The waste nitrogen-containing cotton-based carbon material ozone catalyst contains an asymmetric N-coordinated Fe single-atom structure.
9. The ozone catalyst prepared by the method described in any one of claims 1 to 7, or the ozone catalyst prepared by the method described in claim 8, for ozone catalytic degradation of electron-donating and / or electron-withdrawing pollutants.
10. The application as described in claim 9, characterized in that, The electron-donating group pollutant is p-aminophenol, and the electron-withdrawing group pollutant is p-nitrophenol.