Fluorescent cellulose nanocrystal based on fluorescent fabric and manufacturing process of fluorescent cellulose nanocrystal

Abstract

The invention belongs to the field of nanocellulose, and particularly relates to a fluorescent cellulose nanocrystal based on a fluorescent fabric and a manufacturing process of the fluorescent cellulose nanocrystal. The manufacturing process comprises the following steps: S1, cutting the fluorescent fabric into fluorescent cloth pieces; s2, acid and the fluorescent fabric are mixed; and S3, after the reaction is finished, removing acid to obtain the fluorescent cellulose nanocrystal. According to the method, the fluorescent dyeing textile waste can be effectively recycled under the conditions that the structure of the covalent binding fluorescent dye is completely reserved and dissolution loss of the covalent binding fluorescent dye is avoided. Fluorescent components contained in the fluorescent fabric are effectively reserved in CNC, fiber resource utilization of the waste fluorescent fabric is achieved, pollution to the environment is reduced, meanwhile, the preparation cost of fluorescent CNC raw materials is reduced, and a new feasible way is provided for high-value-added resource utilization of the waste fluorescent fabric.

Description

Technical Field

[0001] This invention belongs to the field of nanocellulose, specifically relating to a fluorescent cellulose nanocrystal based on fluorescent fabric and its manufacturing process. Background Technology

[0002] With the excessive growth of urban textile production and consumption, a large amount of waste textiles have not been efficiently recycled, resulting in a serious waste of fiber resources. Currently, the main methods for disposing of waste textiles are incineration and landfill. Fluorescently dyed textiles contain organic fluorescent dyes that are difficult to biodegrade. Traditional treatment methods not only fail to effectively recover fiber resources but also cause environmental pollution. Furthermore, the inefficient extraction and reuse of fluorescent dyes further exacerbates the problem of resource waste. Summary of the Invention

[0003] The purpose of this invention is to overcome the defects in the prior art and provide a fluorescent cellulose nanocrystal based on fluorescent fabric and its manufacturing process.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A process for preparing fluorescent cellulose nanocrystals based on fluorescent fabric includes the following steps: S1: cutting the fluorescent fabric into fluorescent scraps; the fluorescent fabric is fluorescent pure cotton textile; S2: mixing the fluorescent fabric with an acid for reaction; the reaction temperature is 45℃; the reaction time is 4h; the acid is sulfuric acid; the concentration of the acid is 64 wt%; S3: removing organic fibers that are insoluble in the acid; S4: after the reaction is completed, removing the acid to obtain fluorescent cellulose nanocrystals.

[0005] The fluorescent fabric mentioned in step S1 includes one or any combination of fluorescent cotton fabric, fluorescent linen fabric, fluorescent polyester-cotton blend fabric, and cotton and viscose fiber blend fabric.

[0006] The fluorescent color of the fluorescent fabric mentioned in step S1 includes any one or a mixture of fluorescent yellow, fluorescent red, or fluorescent green.

[0007] The number of shredded fabric pieces is less than or equal to 20. 5 (mm).

[0008] In step S2, the solid-liquid ratio is 1:1.5 to 1:10.

[0009] Between steps S2 and S3, there is also an alkaline fixation reaction; the specific steps of the alkaline fixation reaction are as follows: after the reaction in step S2 is completed, deionized water is added to dilute and terminate the reaction, then the reaction system is allowed to stand, the supernatant is removed, and this operation is repeated. Then, the acid in the system is neutralized with alkali, the pH is adjusted to pH=6, and the system is fixed after neutralization.

[0010] The alkali is one or any combination of sodium hydroxide, sodium carbonate, ammonia, and magnesium oxide; the concentration of the alkali is 2 wt% to 10 wt%; preferably 5 wt%.

[0011] The color-fixing temperature is 30℃~100℃; the color-fixing time is 0.5h~3h. Preferably, it is treated at 60℃ for 1h.

[0012] The specific steps of step S3 are as follows: pass the sample through a sieve of 300 mesh or higher to remove organic fibers that are insoluble in the system; The specific steps of step S4 are as follows: After the color fixation treatment is completed, the reaction system is transferred to a dialysis bag for further dialysis to remove acid, and then ultrasonic treatment is performed to make it dispersed evenly to obtain a CNC suspension. After vacuum freeze-drying, CNC powder is obtained.

[0013] The mixture was transferred to a dialysis bag with a molecular weight of 10,000 and dialyzed until the pH reached neutral to remove acid and small molecule impurities; the dialysis time was 48 h to 96 h; the sonication time was 10 to 30 min.

[0014] The present invention also includes fluorescent cellulose nanocrystals obtained by the preparation process described above.

[0015] The present invention also includes an application of the fluorescent cellulose nanocrystals described herein.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. It can effectively recycle fluorescent dyed textile waste while preserving the covalent bond between fluorescent dyes and fibers and effectively preventing their leaching and loss.

[0017] 2. Effectively retaining the fluorescent components contained in fluorescent fabrics into CNC not only realizes the resource utilization of waste fluorescent fabric fibers and reduces environmental pollution, but also reduces the preparation cost of fluorescent CNC raw materials, providing a practical and feasible new approach for the high-value-added resource utilization of waste fluorescent textiles. Attached Figure Description

[0018] Figure 1 Comparison of the dispersion stability of fluorescent cotton textiles treated with 64 wt% sulfuric acid at different solid-liquid ratios (1:1.5, 1:3, 1:6, 1:10) after acid hydrolysis, dialysis, and static separation, diluted to 1 wt%. Figure 2 Zeta potential diagrams and nanoparticle size distribution diagrams of fluorescent cotton textiles treated with 64 wt% sulfuric acid at different solid-liquid ratios (1:1.5, 1:3, 1:6, 1:10) after acid hydrolysis, dialysis and static separation were obtained. Figure 3Fluorescent cotton textiles treated with 64 wt% sulfuric acid at different solid-liquid ratios (1:1.5, 1:3, 1:6, 1:10) were subjected to acid hydrolysis, dialysis, and static separation. The absorbance and content of fluorescent components in the resulting products were obtained. Figure 4 Zeta potential diagrams and nanoparticle size distribution diagrams of the products obtained after color fixation with different bases (sodium hydroxide, sodium carbonate, ammonia, magnesium oxide); Figure 5 The absorbance diagrams of fluorescent components, the absorbance diagrams of fluorescent components, and the content diagrams of fluorescent components are obtained after fixing with different bases (sodium hydroxide, sodium carbonate, ammonia, and magnesium oxide). Detailed Implementation

[0019] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and preferred embodiments.

[0020] Example 1: A process for preparing fluorescent cellulose nanocrystals based on fluorescent fabric, comprising the following steps: S1: Cut the fluorescent fabric into fluorescent fabric scraps; In this example, take 50 g of yellow fluorescent fabric (the fluorescent fabric has a cotton content of 80% and a spandex content of 20%) and cut it into 0.5 cm × 2 cm scraps; S2: Mix the acid with fluorescent pure cotton fabric; mix with 75 g of 64% sulfuric acid at a solid-liquid ratio of 1:1.5, and react in a water bath at 45℃ for 4 hours. After the reaction is completed, add 20 times the amount of deionized water to stop the reaction.

[0021] S3: Pass the sample through a sieve of 300 mesh or higher to remove organic fibers that are insoluble in the system; S4: After the reaction, the acid was removed to obtain fluorescent cellulose nanocrystals. The mixture was precipitated and the supernatant was removed, and this process was repeated three times. The mixture was then transferred to a dialysis bag with a molecular weight of 10,000 and dialyzed for 72 hours until the pH was neutral. After precipitation for 24 hours, a mixed system with upper and lower layers was obtained. The upper and lower layers were separated and each was sonicated for 10 minutes to ensure uniform dispersion, resulting in a CNC suspension. This suspension was then freeze-dried under vacuum to obtain upper and lower CNC powders. The obtained CNCs were stored for later use.

[0022] To verify that the CNC prepared in this embodiment is a satisfactory and stable CNC, the particle size distribution, zeta potential, and fluorescence properties of the prepared CNC were measured using the following methods: The upper CNC powder was prepared into a 0.1 wt% CNC suspension, and ultrasonically treated for 10 min to obtain a uniformly dispersed suspension. Figure 1 As shown, this embodiment corresponds to a 1:1.5 ratio (upper CNC and lower CNC, and so on for others). The particle size distribution of the upper CNC was measured to be between 30 nm and 500 nm. Figure 2 As shown in (b), this embodiment corresponds to 1.5 mV, and others follow the same pattern. Zeta potential -25.8 mV ( Figure 2 As shown in (a), this example corresponds to a ratio of 1:1.5, and so on for others), with a fluorescence concentration of 0.448 mg / L. Figure 3 As shown in (c), this embodiment corresponds to a ratio of 1:1.5, and others follow the same pattern. Figure 3 In the image, 'a' represents the full-wavelength scan. Figure 3 In the figure, b represents the standard curve; The lower CNC powder and the upper CNC powder were tested using the same method. The particle size distribution of the lower CNC powder was between 60 nm and 250 nm. Figure 2 As shown in (c), this embodiment corresponds to 1.5), Zeta potential -29.5 mV ( Figure 2 As shown in Figure (a), this example corresponds to a 1:1.5 ratio), with a fluorescence concentration of 0.521 mg / L. Figure 3 As shown in (c), this embodiment corresponds to a ratio of 1:1.5, where the CNC dispersion is relatively uniform and the properties are stable.

[0023] Example 2: The preparation steps are the same as in Example 1, except that 64 wt% concentrated sulfuric acid is mixed with fluorescent pure cotton fabric at a solid-liquid ratio (fluorescent fabric to sulfuric acid ratio) of 1:3. The resulting CNC is stored for later use.

[0024] To confirm that the nano-cellulose crystals prepared in this embodiment are uniformly sized and stable, the particle size distribution and stability of the CNC were measured using the processing method and measuring instrument described in Example 1. The particle size distribution of the upper CNC was measured to be between 60 nm and 200 nm. Figure 2 (b) Middle 3 (above), Zeta potential -26.7 mV ( Figure 2 (a) 1:3 (top), fluorescence concentration was 0.369 mg / L ( Figure 3 Middle 1:3 (upper) The particle size distribution of the lower CNC layer is 50 nm-230 nm. Figure 2 (c) Middle 3), Zeta potential -31.1 mV ( Figure 2In (a) at a ratio of 1:3, the fluorescence concentration was 0.401 mg / L. Figure 3 (1:3 ratio in the middle) CNC is evenly dispersed and has stable properties.

[0025] Example 3: The preparation steps are the same as in Example 1, except that 64 wt% concentrated sulfuric acid is mixed with fluorescent pure cotton fabric at a solid-liquid ratio (the ratio of fluorescent fabric to sulfuric acid) of 1:6, and the resulting CNC is stored for later use.

[0026] To confirm that the nanocellulose crystals prepared in this embodiment are uniformly sized and stable, the particle size distribution, zeta potential, and fluorescence properties of the CNC were measured using the processing method and measuring instruments described in Example 1 (see Example 1). Figures 2-3 As shown in the figure, the upper CNC particle size distribution was measured to be between 30 nm and 170 nm, with a Zeta potential of -28.6 mV and a fluorescence concentration of 0.291 mg / L; the lower CNC particle size distribution was between 50 nm and 170 nm, with a Zeta potential of -30.4 mV and a fluorescence concentration of 0.283 mg / L. The particle size distribution was uniform and the properties were stable.

[0027] Example 4: The preparation steps are the same as in Example 1, except that 64 wt% concentrated sulfuric acid is mixed with fluorescent pure cotton fabric at a solid-liquid ratio (fluorescent fabric to sulfuric acid ratio) of 1:10. The resulting CNC is stored for later use.

[0028] To confirm that the nanocellulose crystals prepared in this embodiment are uniformly sized and stable, the particle size distribution, zeta potential, and fluorescence properties of the CNC were measured using the processing method and measuring instruments described in Example 1 (see Example 1). Figures 2-3 As shown in the figure, the particle size distribution of the upper CNC layer was measured to be between 50 nm and 200 nm, with a Zeta potential of -26.9 mV and a fluorescence concentration of 0.281 mg / L; the particle size distribution of the lower CNC layer was between 30 nm and 170 nm, with a Zeta potential of -31.1 mV and a fluorescence concentration of 0.272 mg / L. The particle size distribution was uniform and the properties were stable.

[0029] Example 5: The difference between Example 5 and Example 4 is that an alkaline fixation reaction is included between steps S2 and S3; after the reaction in step S2 is completed, the supernatant is removed, and the acid in the system is neutralized with 5 wt% sodium hydroxide until pH=6. Then the system is heated at 60°C for 1 hour to fix the color.

[0030] To confirm that the nanocellulose crystals prepared in this embodiment are uniformly sized and stable, the particle size distribution, zeta potential, and fluorescence properties of the CNC were measured using the processing method and measuring instruments described in Example 1 (see Example 1). Figures 4-5 As shown, Figures 4-5 The middle layer corresponds to the lower layer CNC), and the particle size distribution of the CNC was measured to be between 25 nm and 200 nm. Figure 4 As shown in Figure b, the original sample corresponds to the lower CNC layer of Example 4), with a Zeta potential of -25.5 mV. Figure 4 As shown in Figure a), the fluorescence concentration was 0.301 mg / L ( Figure 5 As shown in b, Figure 5 (a is the full-wave scan image of Examples 4-8), indicating uniform particle size distribution and stable properties.

[0031] Example 6: The preparation steps are the same as in Example 5, except that the system is neutralized and fixed with 5 wt% sodium carbonate. The resulting CNC is stored for later use.

[0032] To confirm that the nanocellulose crystals prepared in this embodiment are uniform in particle size distribution and stable in properties, the particle size distribution, zeta potential, and fluorescence properties of the above-mentioned CNC were measured using the processing method and measuring instrument described in Example 1. The particle size distribution of the CNC was measured to be between 30 nm and 170 nm, the zeta potential was -23.9 mV, and the fluorescence concentration was 0.297 mg / L. The particle size distribution was uniform and the properties were stable.

[0033] Example 7: The preparation steps are the same as in Example 5, except that the system is neutralized and fixed with 5 wt% ammonia. The resulting CNC is stored for later use.

[0034] To confirm that the nanocellulose crystals prepared in this embodiment are uniform in particle size distribution and stable in properties, the particle size distribution, zeta potential, and fluorescence properties of the above-mentioned CNC were measured using the processing method and measuring instrument described in Example 1. The particle size distribution of the CNC was measured to be between 40 nm and 150 nm, the zeta potential was -28.0 mV, and the fluorescence concentration was 0.343 mg / L. The particle size distribution was uniform and the properties were stable.

[0035] Example 8: The preparation steps are the same as in Example 5, except that the system is neutralized and fixed with 5 wt% magnesium oxide. The resulting CNC is stored for later use.

[0036] To confirm that the nanocellulose crystals prepared in this embodiment are uniform in particle size distribution and stable in properties, the particle size distribution, zeta potential, and fluorescence properties of the above-mentioned CNC were measured using the processing method and measuring instrument described in Example 1. The particle size distribution of the CNC was measured to be between 40 nm and 110 nm, the zeta potential was -19.9 mV, and the fluorescence concentration was 0.312 mg / L. The particle size distribution was uniform and the properties were stable.

[0037] The results showed that after the sulfuric acid hydrolysis reaction, neutralization and color-fixing treatment with alkaline solutions containing different metal ions all exhibited significant color-fixing effects. The zeta potential of the fluorescent CNCs after color-fixing treatment remained stable at around -30 mV, indicating stable system properties and uniform particle size distribution. Comparing the content of fluorescent components, all color-fixed fluorescent CNCs showed higher levels than the untreated group; among them, ammonia treatment showed the best effect, followed by magnesium oxide treatment.

[0038] In summary, the implementation scheme of this application can achieve effective recycling of fluorescent dyed textile waste while completely preserving the structure of the covalently bound fluorescent dye and preventing its leaching and loss. Effectively retaining the fluorescent components contained in the fluorescent fabric within the CNC not only realizes the resource utilization of waste fluorescent fabric fibers and reduces environmental pollution, but also lowers the raw material preparation cost of fluorescent CNC, providing a practical and feasible new approach for the high-value-added resource utilization of waste fluorescent textiles.

[0039] The above description is only a preferred embodiment of the present invention. For those skilled in the art, there will be changes in the specific implementation and application scope based on the ideas of the present invention. The content of this specification should not be construed as a limitation of the present invention.

Claims

1. A process for preparing fluorescent cellulose nanocrystals based on fluorescent fabric, characterized in that, The process includes the following steps: S1: Cutting the fluorescent fabric into fluorescent scraps; S2: Mixing the fluorescent fabric with acid; S3: Remove organic fibers that are insoluble in acid; S4: After the reaction is complete, remove the acid to obtain fluorescent cellulose nanocrystals; The fluorescent fabric has a cotton content of 80% and a spandex content of 20%. The reaction temperature in step S2 is 45℃; the reaction time is 4h; the acid in step S2 is sulfuric acid; and the concentration of the acid is 64wt%.

2. The preparation process of fluorescent cellulose nanocrystals based on fluorescent fabric according to claim 1, characterized in that, The fluorescent color of the fluorescent fabric includes any one or a mixture of fluorescent yellow, fluorescent red, or fluorescent green; the fabric scraps are less than or equal to 20. 5 (mm).

3. The preparation process of fluorescent cellulose nanocrystals based on fluorescent fabric according to claim 1, characterized in that, In step S2, the solid-liquid ratio is 1:1.5 to 1:

10.

4. The preparation process of fluorescent cellulose nanocrystals based on fluorescent fabric according to claim 1, characterized in that, Between steps S2 and S3, there is also an alkaline fixation reaction; the specific steps of the alkaline fixation reaction are as follows: after the reaction in step S2 is completed, deionized water is added to dilute and terminate the reaction, then the reaction system is allowed to stand, the supernatant is removed, and this operation is repeated. Then, the acid in the system is neutralized with alkali, the pH is adjusted to pH=6, and the system is fixed after neutralization. The alkali is one or any combination of sodium hydroxide, sodium carbonate, ammonia, and magnesium oxide; the concentration of the alkali is 2wt%~10wt%; the fixing temperature is 30℃~100℃; and the fixing time is 0.5h~3h.

5. The preparation process of fluorescent cellulose nanocrystals based on fluorescent fabric according to claim 1, characterized in that, The specific steps of step S3 are as follows: pass the sample through a sieve of 300 mesh or higher to remove organic fibers that are insoluble in the system.

6. The preparation process of fluorescent cellulose nanocrystals based on fluorescent fabric according to claim 1, characterized in that, The specific steps of step S4 are as follows: the reaction system is transferred to a dialysis bag for dialysis, then ultrasonically treated to disperse it evenly, to obtain a CNC suspension, which is then freeze-dried under vacuum to obtain CNC powder.

7. The preparation process of fluorescent cellulose nanocrystals based on fluorescent fabric according to claim 6, characterized in that, The mixture was transferred to a dialysis bag with a molecular weight of 10,000 and dialyzed until the pH value reached neutral to remove acid and small molecule impurities; the dialysis treatment time was 48h to 96h; the sonication time was 10 to 30min.

8. Fluorescent cellulose nanocrystals obtained by the preparation process according to any one of claims 1-7.

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