Deodorized and markable regenerated cellulose fiber and preparation method thereof

Abstract

The present invention belongs to the field of functional fibers, and more specifically, is a deodorizing and markable regenerated cellulose fiber and a preparation method thereof. 2 / g‑C 3 N 4 Nanocomposite materials, and select suitable carbon dots for TiO 2 / g‑C 3 N 4 The nanocomposite material is modified, and the components of the coagulation bath are adjusted by pre-spinning blending technology, and the regenerated cellulose fiber with a broad-spectrum light catalytic deodorization function is prepared by wet spinning. The regenerated cellulose fiber prepared by the present invention has an absorption peak in the ultraviolet region at 340nm, and an absorption characteristic peak in the visible light region at 435nm; the ammonia removal reduction rate is ≥85%, the acetic acid removal reduction rate is ≥90%, and the isovaleric acid removal reduction rate is ≥90%; the mechanical properties are excellent, the fiber fineness is 1.11-2.78dtex, the dry breaking strength is 2.7-3.0cN / dtex, and the wet breaking strength is 1.7-2.0cN / dtex; the water washing effect is good, the deodorization effect remains basically unchanged after washing fifty times, and the reduction rates of ammonia, acetic acid and isovaleric acid are all reduced by less than 3%.

Description

Technical Field

[0001] The invention belongs to the technical field of functional fibers, and in particular relates to a deodorizing and markable regenerated cellulose fiber and a preparation method thereof. Background Art

[0002] With the progress of science and technology, economic development, and the improvement of people's living standards, the concept of green, environmentally friendly, healthy and comfortable consumption has become deeply rooted in people's hearts. Malodor (smell) can stimulate people's sensory organs, make people irritable, and affect people's psychological and physiological health. With the acceleration of the aging process of the social population, the problem of "senile odor" has become one of the hot spots of research. "Senior odor" is a kind of body odor emitted by people as they age. When people reach middle age and old age, a fatty acid called palmitoleic acid (hexadecene acid) in the sebum will increase, and the oxidative decomposition reaction will produce ammonia, isovaleric acid, acetic acid and other odorous gases. Malodor (smell) is mainly a mixture of volatile molecules produced by the decomposition of organic matter such as proteins, carbohydrates, and higher fatty acids by bacteria and other microorganisms. The method of eliminating odor can be to inhibit or kill the production of bacteria and other microorganisms and decompose and remove the odorous volatile molecules. Patent CN114381819A discloses a method for preparing antibacterial and deodorizing regenerated cellulose fiber, which extracts polyphenols from plants and modifies cellulose to obtain fibers with antibacterial and deodorizing functions. Patent CN106367831A discloses a method for preparing antibacterial and deodorizing regenerated cellulose fibers by mixing the two substances and adding the dispersion to the cellulose spinning solution using the physical antibacterial effect of graphene and the photocatalytic effect of TiO2; Patent CN105483849A discloses a method for preparing photocatalyst regenerated cellulose fibers, directly adding nano-TiO2 titanium dioxide with photocatalytic effect to the regenerated cellulose fibers to effectively oxidize and decompose volatile organic compounds (VOCs). TiO2 can absorb light energy and stimulate the generation of electron-holes under ultraviolet light, thereby initiating a series of redox reactions, and is not a natural visible light photocatalyst. Patent CN 114713293A also discloses a composite photocatalyst composed of organic covalent skeleton nanomaterials, graphite carbon nitride (g-C3N4) and silver-doped nano-titanium dioxide, and prepares polyacrylonitrile nanofiber membranes containing composite photocatalysts through electrostatic spinning technology.

[0003] As a kind of carbon-based nanomaterial, carbon dots have attracted extensive attention due to their unique properties such as good biocompatibility, low toxicity, high water solubility, chemical inertness and easy functionalization. The particle size of carbon dots is very small, and they can form nanojunctions in close contact with other semiconductor materials. Photogenerated carriers can be transferred between different semiconductors through CQDs, effectively solving the congestion problem of carriers at the interface. Among them, in-plane doping of heteroatoms such as N, S, B, and P in GQDs is an effective method to adjust the band structure, adjust the optical properties and improve the activity of light-driven reactions. In addition, heteroatom-doped carbon dots show strong light absorption in the ultraviolet region, which gradually decays and extends to the visible light region, usually with characteristic absorption peaks at 200-400nm. The above characteristics provide guarantees for improving the catalytic performance, identification and tracing of materials.

[0004] TiO2 can produce photocatalytic effects under ultraviolet light irradiation and is a widely used photocatalyst. As a new type of non-metallic photocatalytic material, g-C3N4 has a wider absorption spectrum range and can play a photocatalytic role under ordinary visible light, photolyzing harmful gases and organic pollutants. At the same time, both have good acid and alkali stability. TiO2 / g-C3N4 nanocomposite materials have good stability, wider photocatalytic application conditions, and better performance. They are suitable for wet spinning to prepare deodorizing functional regenerated cellulose fibers, but after repeated washing, the composite materials are easy to fall off. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a deodorizing and markable regenerated cellulose fiber and a preparation method thereof. A TiO2 / g-C3N4 nanocomposite material is prepared, and suitable carbon dots are selected to modify the TiO2 / g-C3N4 nanocomposite material. Pre-spinning blending technology is used to prepare regenerated cellulose fibers with broad-spectrum photocatalytic antibacterial and deodorizing functions by wet spinning. Carbon dots are modified on the TiO2 / g-C3N4 nanocomposite material to combine the advantages of the three, thereby achieving the improvement of the photocatalytic performance and labeling of the prepared functional regenerated cellulose fibers.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] One of the purposes of the present invention is to prepare a deodorizing and markable regenerated cellulose fiber, wherein the regenerated cellulose fiber contains a carbon-dot-modified TiO2 / g-C3N4 nanocomposite material; its ultraviolet light absorption peak is located at 340nm, and the absorption characteristic peak in the visible light region is located at 435nm; the ammonia removal reduction rate is ≥85%, the acetic acid removal reduction rate is ≥90%, and the isovaleric acid removal reduction rate is ≥90%; the fiber fineness is 1.16-2.76dtex, the dry breaking strength is 2.71-2.96cN / dtex, and the wet breaking strength is 1.72-1.86cN / dtex.

[0008] The second object of the present invention is to provide a method for preparing deodorized and markable regenerated cellulose fibers, the method comprising the following steps:

[0009] Preparation of S1, TiO2 / g-C3N4 nanocomposites

[0010] Using urea, thiourea or melamine as a precursor, a light yellow g-C3N4 powder is prepared by a thermal polymerization method, and the g-C3N4 is added into anhydrous ethanol and dissolved to obtain a g-C3N4 solution;

[0011] Add titanium sulfate aqueous solution while stirring the g-C3N4 solution, continue stirring for 6 to 12 hours, then heat to 70 to 80°C and stir for 2 to 4 hours to obtain a mixed solution; transfer the mixed solution to a reactor, perform hydrothermal reaction at 160 to 180°C for 8 to 12 hours, cool to room temperature after the reaction, centrifuge, wash with deionized water and anhydrous ethanol in turn, dry, and add to a nano grinder for grinding to obtain a TiO2 / g-C3N4 nanocomposite material.

[0012] Preferably, the effective ingredient content of the titanium sulfate aqueous solution is 20%.

[0013] Preferably, the molar ratio of titanium sulfate to g-C3N4 is 1:2-4.

[0014] Preferably, the stirring rate is 200-300 r / min.

[0015] Preferably, the nano-grinder is a JFS-550 ceramic nano-grinder, the grinding speed is 500-1000 r / min, and the grinding time is 60-90 min.

[0016] During the hydrothermal reaction, titanium sulfate hydrolyzes and forms hydrogen bonds with the -NH groups on the surface of g-C3N4, which makes TiO2 nanoparticles grow in situ on the surface of g-C3N4. TiO2 nanoparticles are uniformly loaded on the surface of g-C3N4, with an average particle size of 15 to 30 nm. In addition, the hydrogen ions generated by the hydrolysis of titanium sulfate protonate with the basic groups on the surface of g-C3N4, increasing the porous structure of the g-C3N4 surface and the specific surface area, which is 22.6 to 26.4 m 2 / g, the active sites increase, the photocatalytic and adsorption effects are better, and it also prepares for the subsequent coordination and cross-linking with aluminum ions in the coagulation bath.

[0017] Modification of TiO2 / g-C3N4 Nanocomposites by S2 and Carbon Dots

[0018] The carbon dots are dissolved in anhydrous ethanol to obtain an alcohol solution of the carbon dots; the alcohol solution of the carbon dots is added to the dispersion of the TiO2 / g-C3N4 nanocomposite material in a certain proportion, and after fully reacting for 50 to 90 minutes, the carbon dots are adsorbed on the surface of the TiO2 / g-C3N4 nanocomposite material; after the reaction is completed, the carbon dots are centrifuged, washed, and dried to obtain the TiO2 / g-C3N4 nanocomposite material modified with carbon dots.

[0019] Preferably, the carbon dots are nitrogen-doped carbon quantum dots (NGQDs) prepared with 1,3-dihydroxynaphthalene and ethylenediamine hydrochloride as carbon sources, with an excitation wavelength of 500 nm, an emission wavelength of 600 nm, and a UV-visible absorption spectrum in aqueous solution with two absorption bands, the center of the UV region is located at 340 nm, and the absorption characteristic peak in the visible light region is 435 nm, and there is a broad tail in the visible light region extending beyond 650 nm.

[0020] Preferably, the amount of the carbon dots added is 5 to 10 wt % of the TiO 2 content in the dispersion of the TiO 2 / g-C 3 N 4 nanocomposite material.

[0021] S3. Preparation of blended spinning solution

[0022] Cotton pulp, wood pulp, bamboo pulp or a mixture thereof is selected as raw material, and a cellulose spinning solution is prepared through processes such as impregnation, pressing, crushing, aging, yellowing, dissolving, filtering and degassing; a dispersion of a carbon dot-modified TiO2 / g-C3N4 nanocomposite material is added to the cellulose spinning solution in proportion before spinning and mixed evenly to prepare a blended spinning solution.

[0023] Preferably, the viscosity of the cellulose spinning solution is 50-80s (falling ball method), the degree of maturity is 20-30mL (10% NH4CL), the methyl cellulose content is 7.2-8.2wt%, and the sodium hydroxide content is 4.5-5.6wt%.

[0024] Preferably, the added amount of the carbon dot-modified TiO2 / g-C3N4 nanocomposite material is 0.5-2.0 wt% of the cellulose cellulose content in the cellulose spinning solution.

[0025] S4, Spinning

[0026] After the blended spinning solution is ejected from the spinneret, it is formed and drawn in a coagulation bath to obtain a primary fiber bundle. The bundle is further drawn in a second bath and enters the post-processing process.

[0027] Preferably, in the coagulation bath, sulfuric acid is 70-90 g / L, zinc sulfate is 40-60 g / L, sodium sulfate is 210-240 g / L, aluminum sulfate is 8-15 g / L, the reaction temperature is 35-40° C., and the draft in the coagulation bath is controlled at 0-30%.

[0028] Preferably, the H2SO4 content in the second bath is 20-30 g / L, the bath temperature is controlled at 75-95°C, and the draft in the second bath is controlled at 60-100%.

[0029] The components of the coagulation bath are crucial to the formation of fiber bundles. Sulfuric acid can decompose cellulose sulfonate to generate regenerated cellulose, sodium sulfate promotes the coagulation and formation of viscose, and zinc sulfate reacts with sodium cellulose sulfonate to generate cellulose zinc sulfonate with a uniform and fine crystalline structure. Reduce the concentration of sulfuric acid and sodium sulfate in the coagulation bath, increase the concentration of zinc sulfate, slow down the coagulation rate of the fiber, and ensure that the carbon point-modified TiO2 / g-C3N4 nanocomposite in the blended spinning solution is evenly distributed inside and outside the fiber; reduce drafting to avoid the breakage of the incompletely formed primary fiber bundles; add aluminum sulfate to the coagulation bath. Aluminum ions are positive trivalent, with high charge and small radius, and stronger complexing ability. One aluminum ion can form a complex with multiple triazine rings in g-C3N4 to obtain a cross-linked structure that runs through the fiber, which is more tightly and stably combined with the fiber, and the cross-linked structure can also improve the fiber strength. Similarly, trivalent iron ions can also coordinate and complex with triazine rings, but the trivalent iron ion complex is color-developing, which will affect the appearance of the fiber, so aluminum ions are selected here. In the second bath, the unformed primary fiber tows are completely solidified, further improving the fiber strength.

[0030] S5. Post-processing

[0031] The fibers after double-bath drawing are washed, desulfurized, bleached, oiled, dried and wound to obtain deodorized and markable regenerated cellulose fibers.

[0032] Due to the adoption of the above technical solution, the technical effects achieved by the present invention are:

[0033] 1. The deodorizing and markable regenerated cellulose fiber prepared by the present invention has excellent mechanical properties, wherein the fiber fineness is 1.16-2.76 dtex, the dry breaking strength is 2.71-2.96 cN / dtex, and the wet breaking strength is 1.72-1.86 cN / dtex.

[0034] 2. The deodorizing markable regenerated cellulose fiber prepared by the present invention has good deodorizing effect, with an ammonia reduction rate of ≥85%, an acetic acid reduction rate of ≥90%, and an isovaleric acid reduction rate of ≥90% (determined in accordance with GB / T 33610.3-2019); and has good water washing resistance. The deodorizing effect remains basically unchanged after washing fifty times, and the reduction rates of ammonia, acetic acid and isovaleric acid are all reduced by less than 3%.

[0035] 3. The deodorizing and markable regenerated cellulose fiber prepared by the present invention has excellent photocatalytic performance, combines the advantages of carbon quantum dots, TiO2 and g-C3N4, and has broad application prospects. The absorption peak in the ultraviolet light region is 340nm, and the absorption characteristic peak in the visible light region is 435nm. DETAILED DESCRIPTION

[0036] The present invention is further described below in conjunction with specific embodiments.

[0037] Embodiment 1: A deodorizing and markable regenerated cellulose fiber and a preparation method thereof, the preparation method comprising the following steps:

[0038] Preparation of S1, TiO2 / g-C3N4 nanocomposites

[0039] Using urea and thiourea as precursors, a light yellow g-C3N4 powder is prepared by a thermal polymerization method, and the g-C3N4 is added into anhydrous ethanol to dissolve to obtain a g-C3N4 solution; the molar ratio of the urea to the thiourea is 3:1.

[0040] Add titanium sulfate aqueous solution while stirring the g-C3N4 solution, continue stirring for 10 hours, then heat to 75°C and stir for 3 hours to obtain a mixed solution; transfer the mixed solution to a reactor, perform hydrothermal reaction at 170°C for 10 hours, cool to room temperature after the reaction, centrifuge, wash with deionized water and anhydrous ethanol in sequence, dry, and add to a nano grinder for grinding to obtain a TiO2 / g-C3N4 nanocomposite material.

[0041] The effective component content of the titanium sulfate aqueous solution is 20%.

[0042] The molar ratio of the titanium sulfate to g-C3N4 is 1:3.

[0043] The stirring rate is 250 r / min.

[0044] The nano-grinder is a JFS-550 ceramic nano-grinder, the grinding speed is 700 r / min, and the grinding time is 80 min.

[0045] During the hydrothermal reaction, titanium sulfate hydrolyzes and forms hydrogen bonds with the -NH groups on the surface of g-C3N4, which makes TiO2 nanoparticles grow in situ on the surface of g-C3N4. TiO2 nanoparticles are uniformly loaded on the surface of g-C3N4, with an average particle size of 20nm. In addition, the hydrogen ions generated by the hydrolysis of titanium sulfate protonate with the basic groups on the surface of g-C3N4, increasing the porous structure of the g-C3N4 surface and the specific surface area. The average specific surface area is 26.4m 2 / g, the active sites increase, the photocatalytic and adsorption effects are better, and it also prepares for the subsequent coordination and cross-linking with aluminum ions in the coagulation bath.

[0046] Modification of TiO2 / g-C3N4 Nanocomposites by S2 and Carbon Dots

[0047] The carbon dots are dissolved in anhydrous ethanol to obtain an alcohol solution of the carbon dots; the alcohol solution of the carbon dots is added to the dispersion of the TiO2 / g-C3N4 nanocomposite material in a certain proportion, and after fully reacting for 60 minutes, the carbon dots are adsorbed on the surface of the TiO2 / g-C3N4 nanocomposite material. After the reaction is completed, the carbon dots are centrifuged, washed, and dried to obtain the TiO2 / g-C3N4 nanocomposite material modified with carbon dots.

[0048] The carbon dots are nitrogen-doped carbon quantum dots (NGQDs) prepared with 1,3-dihydroxynaphthalene and ethylenediamine hydrochloride as carbon sources, with an excitation wavelength of 500 nm, an emission wavelength of 600 nm, and a UV-visible absorption spectrum in aqueous solution with two absorption bands, the center of the UV region is located at 340 nm, and the absorption characteristic peak in the visible region is 435 nm, and there is a broad tail in the visible region extending beyond 650 nm.

[0049] The amount of carbon dots added is 8wt% of the TiO2 content in the dispersion of the TiO2 / g-C3N4 nanocomposite material.

[0050] S3. Preparation of blended spinning solution

[0051] Cotton pulp is selected as raw material, and a cellulose spinning solution is prepared through processes such as impregnation, pressing, crushing, aging, yellowing, dissolving, filtering, and degassing. A dispersion of a carbon dot-modified TiO2 / g-C3N4 nanocomposite material is added to the cellulose spinning solution in proportion before spinning and mixed evenly to prepare a blended spinning solution.

[0052] The viscosity of the cellulose spinning solution is 62 s (falling ball method), the degree of maturity is 26 mL (10% NH4CL), the methyl cellulose content is 7.8 wt%, and the sodium hydroxide content is 5.2 wt%.

[0053] The addition amount of the carbon dot-modified TiO2 / g-C3N4 nanocomposite material is 1.2wt% of the methyl cellulose content in the cellulose spinning solution.

[0054] S4, Spinning

[0055] After the blended spinning solution is ejected from the spinneret, it is formed and drawn in a coagulation bath to obtain a primary fiber bundle. The bundle is further drawn in a second bath and enters the post-processing process.

[0056] In the coagulation bath, sulfuric acid is 80 g / L, zinc sulfate is 50 g / L, sodium sulfate is 220 g / L, aluminum sulfate is 13 g / L, the reaction temperature is 38° C., and the draft in the coagulation bath is controlled at 22%.

[0057] The H2SO4 content in the second bath is 25 g / L, the bath temperature is controlled at 85°C, and the draft in the second bath is controlled at 86%.

[0058] S5. Post-processing

[0059] The fibers after double-bath drawing are washed, desulfurized, bleached, oiled, dried and wound to obtain deodorized and markable regenerated cellulose fibers.

[0060] The deodorized and markable regenerated cellulose fiber prepared in Example 1 has a fineness of 1.33 dtex, a dry breaking strength of 2.96 cN / dtex, and a wet breaking strength of 1.86 cN / dtex; an ammonia removal reduction rate of 90%, an acetic acid removal reduction rate of 96%, and an isovaleric acid removal reduction rate of 94%. After washing 50 times, the reduction rates of ammonia, acetic acid, and isovaleric acid are reduced by an average of 2.3%; the absorption peak in the ultraviolet light region is 340 nm, and the absorption characteristic peak in the visible light region is 435 nm.

[0061] Embodiment 2: A deodorizing and markable regenerated cellulose fiber and a preparation method thereof, the preparation method comprising the following steps:

[0062] Preparation of S1, TiO2 / g-C3N4 nanocomposites

[0063] Using urea and thiourea as precursors, a light yellow g-C3N4 powder is prepared by a thermal polymerization method, and the g-C3N4 is added into anhydrous ethanol to dissolve to obtain a g-C3N4 solution; the molar ratio of the urea to the thiourea is 3:1.

[0064] Add titanium sulfate aqueous solution while stirring the g-C3N4 solution, continue stirring for 6 hours, then heat to 70°C and stir for 2 hours to obtain a mixed solution; transfer the mixed solution to a reactor, perform hydrothermal reaction at 160°C for 8 hours, cool to room temperature after the reaction, centrifuge, wash with deionized water and anhydrous ethanol in turn, dry, and add to a nano grinder for grinding to obtain a TiO2 / g-C3N4 nanocomposite material.

[0065] The effective component content of the titanium sulfate aqueous solution is 20%.

[0066] The molar ratio of the titanium sulfate to g-C3N4 is 1:2.

[0067] The stirring rate is 200 r / min.

[0068] The nano-grinder is a JFS-550 ceramic nano-grinder, the grinding speed is 500 r / min, and the grinding time is 60 min.

[0069] During the hydrothermal reaction, titanium sulfate hydrolyzes and forms hydrogen bonds with the -NH groups on the surface of g-C3N4, which makes TiO2 nanoparticles grow in situ on the surface of g-C3N4. TiO2 nanoparticles are uniformly loaded on the surface of g-C3N4, with an average particle size of 30nm. In addition, the hydrogen ions generated by the hydrolysis of titanium sulfate protonate with the basic groups on the surface of g-C3N4, increasing the porous structure of the g-C3N4 surface and the specific surface area to 22.6m 2 / g, the active sites increase, the photocatalytic and adsorption effects are better, and it also prepares for the subsequent coordination and cross-linking with aluminum ions in the coagulation bath.

[0070] Modification of TiO2 / g-C3N4 Nanocomposites by S2 and Carbon Dots

[0071] The carbon dots are dissolved in anhydrous ethanol to obtain an alcohol solution of the carbon dots; the alcohol solution of the carbon dots is added to the dispersion of the TiO2 / g-C3N4 nanocomposite material in a certain proportion, and after fully reacting for 50 minutes, the carbon dots are adsorbed on the surface of the TiO2 / g-C3N4 nanocomposite material. After the reaction is completed, the carbon dots are centrifuged, washed, and dried to obtain the TiO2 / g-C3N4 nanocomposite material modified with carbon dots.

[0072] The carbon dots are nitrogen-doped carbon quantum dots (NGQDs) prepared with 1,3-dihydroxynaphthalene and ethylenediamine hydrochloride as carbon sources, with an excitation wavelength of 500 nm, an emission wavelength of 600 nm, and a UV-visible absorption spectrum in aqueous solution with two absorption bands, the center of the UV region is located at 340 nm, and the absorption characteristic peak in the visible region is 435 nm, and there is a broad tail in the visible region extending beyond 650 nm.

[0073] The amount of carbon dots added is 5wt% of the TiO2 content in the dispersion of the TiO2 / g-C3N4 nanocomposite material.

[0074] S3. Preparation of blended spinning solution

[0075] Cotton pulp is selected as raw material, and a cellulose spinning solution is prepared through processes such as impregnation, pressing, crushing, aging, yellowing, dissolving, filtering, and degassing. A dispersion of a carbon dot-modified TiO2 / g-C3N4 nanocomposite material is added to the cellulose spinning solution in proportion before spinning and mixed evenly to prepare a blended spinning solution.

[0076] The cellulose spinning solution has a viscosity of 50 s (falling ball method), a maturity of 20 mL (10% NH4CL), a methyl cellulose content of 7.2 wt %, and a sodium hydroxide content of 4.5 wt %.

[0077] The addition amount of the carbon dot-modified TiO2 / g-C3N4 nanocomposite material is 0.5wt% of the methyl cellulose content in the cellulose spinning solution.

[0078] S4, Spinning

[0079] After the blended spinning solution is ejected from the spinneret, it is formed and drawn in a coagulation bath to obtain a primary fiber bundle. The bundle is further drawn in a second bath and enters the post-processing process.

[0080] In the coagulation bath, sulfuric acid is 90 g / L, zinc sulfate is 40 g / L, sodium sulfate is 210 g / L, aluminum sulfate is 8 g / L, the reaction temperature is 35° C., and the draft in the coagulation bath is controlled at 27%.

[0081] The H2SO4 content in the second bath is 20 g / L, the bath temperature is controlled at 75°C, and the draft in the second bath is controlled at 72%.

[0082] S5. Post-processing

[0083] The fibers after double-bath drawing are washed, desulfurized, bleached, oiled, dried and wound to obtain deodorized and markable regenerated cellulose fibers.

[0084] The deodorized and markable regenerated cellulose fiber prepared in Example 2 has a fineness of 2.76 dtex, a dry breaking strength of 2.71 cN / dtex, and a wet breaking strength of 1.72 cN / dtex; the ammonia removal reduction rate is 86%, the acetic acid removal reduction rate is 93%, and the isovaleric acid removal reduction rate is 90%. After washing 50 times, the reduction rates of ammonia, acetic acid and isovaleric acid are reduced by an average of 2.8%; the absorption peak in the ultraviolet light region is 340 nm, and the absorption characteristic peak in the visible light region is 435 nm.

[0085] Embodiment 3: A deodorizing and markable regenerated cellulose fiber and a preparation method thereof, the preparation method comprising the following steps:

[0086] Preparation of S1, TiO2 / g-C3N4 nanocomposites

[0087] Using urea and thiourea as precursors, a light yellow g-C3N4 powder is prepared by a thermal polymerization method, and the g-C3N4 is added into anhydrous ethanol to dissolve to obtain a g-C3N4 solution; the molar ratio of the urea to the thiourea is 3:1.

[0088] Add titanium sulfate aqueous solution while stirring the g-C3N4 solution, continue stirring for 12 hours, then heat to 80°C and stir for 4 hours to obtain a mixed solution; transfer the mixed solution to a reactor, perform hydrothermal reaction at 180°C for 12 hours, cool to room temperature after the reaction, centrifuge, wash with deionized water and anhydrous ethanol in turn, dry, and add to a nano grinder for grinding to obtain a TiO2 / g-C3N4 nanocomposite material.

[0089] The effective component content of the titanium sulfate aqueous solution is 20%.

[0090] The molar ratio of the titanium sulfate to g-C3N4 is 1:4.

[0091] The stirring rate is 300 r / min.

[0092] The nano-grinder is a JFS-550 ceramic nano-grinder, the grinding speed is 1000 r / min, and the grinding time is 90 min.

[0093] During the hydrothermal reaction, titanium sulfate hydrolyzes and forms hydrogen bonds with the -NH groups on the surface of g-C3N4, which makes TiO2 nanoparticles grow in situ on the surface of g-C3N4. TiO2 nanoparticles are uniformly loaded on the surface of g-C3N4, with an average particle size of 15nm. In addition, the hydrogen ions generated by the hydrolysis of titanium sulfate protonate with the basic groups on the surface of g-C3N4, increasing the porous structure of the g-C3N4 surface and the specific surface area to 24.3m 2 / g, the active sites increase, the photocatalytic and adsorption effects are better, and it also prepares for the subsequent coordination and cross-linking with aluminum ions in the coagulation bath.

[0094] Modification of TiO2 / g-C3N4 Nanocomposites by S2 and Carbon Dots

[0095] The carbon dots are dissolved in anhydrous ethanol to obtain an alcohol solution of the carbon dots; the alcohol solution of the carbon dots is added to the dispersion of the TiO2 / g-C3N4 nanocomposite material in a certain proportion, and after fully reacting for 90 minutes, the carbon dots are adsorbed on the surface of the TiO2 / g-C3N4 nanocomposite material. After the reaction is completed, the carbon dots are centrifuged, washed, and dried to obtain the TiO2 / g-C3N4 nanocomposite material modified with carbon dots.

[0096] The carbon dots are nitrogen-doped carbon quantum dots (NGQDs) prepared with 1,3-dihydroxynaphthalene and ethylenediamine hydrochloride as carbon sources, with an excitation wavelength of 500 nm, an emission wavelength of 600 nm, and a UV-visible absorption spectrum in aqueous solution with two absorption bands, the center of the UV region is located at 340 nm, and the absorption characteristic peak in the visible region is 435 nm, and there is a broad tail in the visible region extending beyond 650 nm.

[0097] The amount of carbon dots added is 10wt% of the TiO2 content in the dispersion of the TiO2 / g-C3N4 nanocomposite material.

[0098] S3. Preparation of blended spinning solution

[0099] Cotton pulp is selected as raw material, and a cellulose spinning solution is prepared through processes such as impregnation, pressing, crushing, aging, yellowing, dissolving, filtering, and degassing. A dispersion of a carbon dot-modified TiO2 / g-C3N4 nanocomposite material is added to the cellulose spinning solution in proportion before spinning and mixed evenly to prepare a blended spinning solution.

[0100] The cellulose spinning solution has a viscosity of 80 s (falling ball method), a maturity of 30 mL (10% NH4CL), a methyl cellulose content of 8.2 wt %, and a sodium hydroxide content of 5.6 wt %.

[0101] The addition amount of the carbon dot-modified TiO2 / g-C3N4 nanocomposite material is 2.0wt% of the methyl cellulose content in the cellulose spinning solution.

[0102] S4, Spinning

[0103] After the blended spinning solution is ejected from the spinneret, it is formed and drawn in a coagulation bath to obtain a primary fiber bundle. The bundle is further drawn in a second bath and enters the post-processing process.

[0104] In the coagulation bath, sulfuric acid is 70 g / L, zinc sulfate is 60 g / L, sodium sulfate is 240 g / L, aluminum sulfate is 15 g / L, the reaction temperature is 40° C., and the draft in the coagulation bath is controlled at 16%.

[0105] The H2SO4 content in the second bath is 30 g / L, the bath temperature is controlled at 95°C, and the draft in the second bath is controlled at 85%.

[0106] S5. Post-processing

[0107] The fibers after double-bath drawing are washed, desulfurized, bleached, oiled, dried and wound to obtain deodorized and markable regenerated cellulose fibers.

[0108] The deodorized and markable regenerated cellulose fiber prepared in Example 3 has a fineness of 1.16 dtex, a dry breaking strength of 2.82 cN / dtex, and a wet breaking strength of 1.78 cN / dtex; an ammonia removal reduction rate of 92%, an acetic acid removal reduction rate of 99%, and an isovaleric acid removal reduction rate of 98%. After washing 50 times, the reduction rates of ammonia, acetic acid, and isovaleric acid are reduced by an average of 2.5%; the absorption peak in the ultraviolet light region is 340 nm, and the absorption characteristic peak in the visible light region is 435 nm.

[0109] Comparative Example 1

[0110] Representative Example 1 was selected, and the aluminum sulfate in the coagulation bath was replaced by an equal amount of zinc sulfate. The rest was consistent with Example 1. As Comparative Example 1, the prepared fiber had a fineness of 1.24 dtex, a dry breaking strength of 2.62 cN / dtex, and a wet breaking strength of 1.54 cN / dtex; the ammonia removal reduction rate was 90%, the acetic acid removal reduction rate was 96%, and the isovaleric acid removal reduction rate was 94%. After washing 50 times with water, the reduction rates of ammonia, acetic acid and isovaleric acid were reduced by an average of 6.3%; the absorption peak in the ultraviolet light region was 340 nm, and the absorption characteristic peak in the visible light region was 435 nm.

[0111] Comparative Example 2

[0112] Representative Example 1 was selected, and the aluminum sulfate in the coagulation bath was removed. The rest were consistent with Example 1. As Comparative Example 2, the prepared fiber had a fineness of 1.26 dtex, a dry breaking strength of 2.3 cN / dtex, and a wet breaking strength of 1.21 cN / dtex; the ammonia removal reduction rate was 90%, the acetic acid removal reduction rate was 96%, and the isovaleric acid removal reduction rate was 94%. After washing 50 times with water, the reduction rates of ammonia, acetic acid and isovaleric acid were reduced by an average of 10.2%; the absorption peak in the ultraviolet light region was 340 nm, and the absorption characteristic peak in the visible light region was 435 nm.

[0113] It can be seen from Example 1, Comparative Example 1 and Comparative Example 2 that the triazine ring in g-C3N4 can also coordinate and crosslink with zinc ions, but the stability and binding force are far inferior to trivalent aluminum ions, and the crosslinking structure is not as tight as Example 1. Therefore, the strength of Comparative Example 1 becomes smaller, and the reduction rate of ammonia, acetic acid and isovaleric acid decreases more after washing with water 50 times; while the zinc sulfate content of Comparative Example 2 is reduced compared with Comparative Example 1, the zinc ions coordinated and crosslinked with the triazine ring are insufficient, and the crosslinking structure is reduced. Therefore, the strength of Comparative Example 2 decreases compared with Comparative Example 1, and the reduction rate of ammonia, acetic acid and isovaleric acid is lower after washing with water 50 times. Comparative Examples 1 and Comparative Example 2 are far inferior to Example 1.

[0114] Unless otherwise specified, the ratios and percentages described in the present invention are all weight ratios and weight percentages; and the raw materials are all commercially available.

[0115] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing deodorized and markable regenerated cellulose fiber, characterized in that: The preparation method includes preparation of TiO2 / g-C3N4 nanocomposite material, modification of TiO2 / g-C3N4 nanocomposite material by carbon dots, preparation of co-blended spinning solution, spinning forming and post-treatment; The TiO2 / g-C3N4 nanocomposite material is prepared by: using urea, thiourea or melamine as a precursor, preparing light yellow g-C3N4 powder by a thermal polymerization method, adding g-C3N4 into anhydrous ethanol to dissolve, and obtaining a g-C3N4 solution; Adding titanium sulfate aqueous solution while stirring the g-C3N4 solution, continuing stirring for 6 to 12 hours, then heating to 70 to 80° C. and stirring for 2 to 4 hours to obtain a mixed solution; transferring the mixed solution to a reaction kettle, performing a hydrothermal reaction at 160 to 180° C. for 8 to 12 hours, cooling to room temperature after the reaction, centrifuging, washing with deionized water and anhydrous ethanol in sequence, drying, adding to a nano grinder, and grinding to obtain a TiO2 / g-C3N4 nanocomposite material; The modification of the TiO2 / g-C3N4 nanocomposite material by carbon dots is as follows: dissolving the carbon dots in anhydrous ethanol to obtain an alcohol solution of the carbon dots; adding the alcohol solution of the carbon dots to a dispersion of the TiO2 / g-C3N4 nanocomposite material in a certain proportion, fully reacting for 50 to 90 minutes, allowing the carbon dots to be adsorbed on the surface of the TiO2 / g-C3N4 nanocomposite material; centrifuging, washing, and drying after the reaction is completed to obtain the TiO2 / g-C3N4 nanocomposite material modified with carbon dots; The spinning process is as follows: after the blended spinning solution is ejected from the spinneret, it is formed and drawn in a coagulation bath to obtain a primary fiber bundle, and the bundle is further drawn in a second bath and enters a post-processing process; The blended spinning solution contains a dispersion of a carbon-dot-modified TiO2 / g-C3N4 nanocomposite material; In the coagulation bath, sulfuric acid is 70-90 g / L, zinc sulfate is 40-60 g / L, sodium sulfate is 210-240 g / L, aluminum sulfate is 8-15 g / L, the reaction temperature is 35-40° C., and the draft in the coagulation bath is controlled at 0-30%; The H2SO4 content in the second bath is 20-30 g / L, the bath temperature is controlled at 75-95°C, and the draft in the second bath is controlled at 60-100%.

2. The method for preparing a deodorized and markable regenerated cellulose fiber according to claim 1, characterized in that: The effective ingredient content of the titanium sulfate aqueous solution is 20%; The molar ratio of the titanium sulfate to g-C3N4 is 1:2-4.

3. The method for preparing a deodorized and markable regenerated cellulose fiber according to claim 1, characterized in that: The stirring rate is 200-300 r / min; The nano-grinder is a JFS-550 ceramic nano-grinder, the grinding speed is 500-1000 r / min, and the grinding time is 60-90 min.

4. The method for preparing a deodorized and markable regenerated cellulose fiber according to claim 1, characterized in that: The carbon dots are nitrogen-doped carbon quantum dots prepared by taking 1,3-dihydroxynaphthalene and ethylenediamine hydrochloride as carbon sources.

5. The method for preparing a deodorized and markable regenerated cellulose fiber according to claim 1, characterized in that: The amount of the carbon dots added is 5-10 wt % of the TiO 2 content in the dispersion of the TiO 2 / g-C 3 N 4 nanocomposite material.

6. The method for preparing a deodorized and markable regenerated cellulose fiber according to claim 1, characterized in that: The preparation of the blended spinning solution is as follows: cotton pulp, wood pulp, bamboo pulp or a mixture thereof is selected as raw material, and a cellulose spinning solution is obtained through the processes of impregnation, pressing, crushing, aging, yellowing, dissolving, filtering and degassing; a dispersion of a carbon dot-modified TiO2 / g-C3N4 nanocomposite material is added to the cellulose spinning solution in proportion before spinning and the mixture is evenly mixed to obtain a blended spinning solution.

7. The method for preparing a deodorized and markable regenerated cellulose fiber according to claim 6, characterized in that: The viscosity of the cellulose spinning solution using the falling ball method is 50-80s, the maturity using 10% NH4Cl is 20-30mL, the methyl cellulose content is 7.2-8.2wt%, and the sodium hydroxide content is 4.5-5.6wt%.

8. The method for preparing a deodorized and markable regenerated cellulose fiber according to claim 6, characterized in that: The addition amount of the carbon dot-modified TiO2 / g-C3N4 nanocomposite material is 0.5-2.0wt% of the methyl cellulose content in the cellulose spinning solution.

9. The method for preparing a deodorized and markable regenerated cellulose fiber according to claim 1, characterized in that: The post-treatment is as follows: the fibers after the two-bath drafting are washed, desulfurized, bleached, oiled, dried, and wound to obtain deodorized and markable regenerated cellulose fibers.

10. The deodorizing and markable regenerated cellulose fiber prepared by the preparation method according to any one of claims 1 to 9, characterized in that: The fiber has a fineness of 1.16 to 2.76 dtex, a dry breaking strength of 2.71 to 2.96 cN / dtex, and a wet breaking strength of 1.72 to 1.86 cN / dtex.