Modified fiber material, preparation method and application

Abstract

The invention relates to a modified fiber material, a preparation method and application. The preparation method of the modified fiber material comprises the following steps: activating fibers, and then freeze-drying to obtain pretreated fibers; mixing the pretreated fiber, a disilane system and a catalyst, heating and reacting to obtain silane modified fiber; the preparation method comprises the following steps: modifying nano titanium dioxide by adopting a silane coupling agent to obtain modified nano titanium dioxide; dispersing the modified nano titanium dioxide in a solvent to obtain a dispersion liquid; and soaking the silane modified fiber in the dispersion liquid to obtain the modified fiber material. The invention also provides the modified fiber material prepared by the method. The invention also provides an application of the modified fiber material prepared by the preparation method as an adsorbent. The invention solves the problem of limited adsorption efficiency of the existing earthy smell substance adsorption material, and the problems of high cost and obvious adsorption capacity attenuation after regeneration of the existing earthy smell substance adsorption material.

Description

Technical Field

[0001] The present invention relates to the technical field of water treatment, and in particular to a modified fiber material, a preparation method and an application thereof. Background Art

[0002] The presence of earthy odor substances has long been a concern in the field of water treatment technology. These substances, primarily geosmin and 2-methylisoborneol, are typically produced by naturally occurring microorganisms such as actinomycetes (e.g., Streptomyces) and cyanobacteria (e.g., Anabaena) through complex metabolic processes.

[0003] Actinomycetes, microorganisms widely found in soil, multiply and produce metabolites such as geosmin and 2-methylisoborneol when the soil environment changes, such as changes in moisture and temperature. Cyanobacteria are also prone to growing and producing these odorous substances in conditions such as eutrophication of water bodies.

[0004] These earthy-smelling substances have extremely low thresholds and can be keenly detected by the human olfactory system even at extremely low concentrations, thus having a significant impact on water, aquatic products and various products that need to maintain a good smell, resulting in a decline in product quality and affecting consumer acceptance.

[0005] Furthermore, earthy-smelling substances exhibit high hydrophobicity, which makes them less soluble in water and more likely to bind to organic matter or hydrophobic surfaces. This property increases the difficulty of removing them, and traditional treatment methods often fail to achieve ideal removal results.

[0006] Among existing methods for removing earthy odors, adsorption technology is widely used. Activated carbon, as a traditional adsorption material, exhibits a moderate adsorption effect on earthy odors. However, its application also has limitations. Firstly, its relatively high cost makes it a significant economic burden for large-scale applications. Secondly, the microporous structure of activated carbon (specific surface area 1200-1500 m² / g) is easily clogged by competitive adsorption by organic matter in the water. This not only reduces the adsorption capacity of earthy odors, but also significantly decreases after 3-5 regenerations, typically by 40-60%. This not only further increases treatment costs but also poses a risk of secondary environmental pollution.

[0007] Given the shortcomings of traditional adsorption materials in removing earthy odor substances, finding a new adsorption material with lower cost, better adsorption effect and easier regeneration has become an urgent problem to be solved. Summary of the Invention

[0008] In view of this, the purpose of the present invention is to provide a modified fiber material, preparation method and application to solve the problem of limited adsorption efficiency of existing earthy odor adsorption materials, as well as the problem of high cost and obvious attenuation of adsorption capacity after regeneration of existing earthy odor adsorption materials.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is as follows: A method for preparing a modified fiber material comprises the following steps: S1. Pretreatment: Activating the fibers to increase the exposure of hydroxyl groups in the fiber material, followed by freeze-drying to preserve the three-dimensional porous structure of the fibers to obtain pretreated fibers. S2, silane modification: pretreated fiber, bisilane system and catalyst are mixed and heated to react to obtain silane-modified fiber; S3. Loading: Nano-titanium dioxide (TiO2) is modified with a silane coupling agent to obtain modified nano-titanium dioxide; the modified nano-titanium dioxide is dispersed in a solvent to obtain a dispersion; and the silane-modified fiber is immersed in the dispersion to obtain a modified fiber material.

[0010] According to the above technical approach, first, during the pretreatment step, the fibers are activated to increase the number of exposed hydroxyl groups in the fiber material. Hydroxyl groups are highly reactive functional groups that can undergo chemical or physical adsorption with chemical groups in earthy-smelling substances. This increase in exposed sites means more active sites available for adsorption on the fiber surface, providing more "anchor points" for the adsorption process, allowing earthy-smelling substances to more effectively bind to the fiber material and improve adsorption efficiency. Second, the three-dimensional porous structure of the fibers, preserved after freeze-drying, provides excellent channels for the diffusion and adsorption of earthy-smelling substances. This porous structure increases the specific surface area of the fiber material, allowing more fiber surface to come into contact with earthy-smelling substances. Furthermore, the pores within the porous structure can accommodate earthy-smelling substance molecules, promoting their diffusion and adsorption within the fiber material, further improving adsorption efficiency. Third, during the loading step, nano-titanium dioxide modified with a silane coupling agent is loaded onto the silane-modified fibers. Nano-titanium dioxide has a large specific surface area and high surface energy, making it suitable for adsorbing earthy-smelling substances. When combined with fiber materials, it creates additional adsorption sites on the fiber surface, further enhancing the material's ability to adsorb earthy odors. Furthermore, nano-titanium dioxide may also possess photocatalytic properties, capable of decomposing adsorbed earthy odors under illumination. This synergistic effect of adsorption and degradation further enhances the removal of earthy odors, effectively resolving the limited adsorption efficiency of existing earthy odor adsorption materials.

[0011] The fiber material itself is usually widely available and relatively inexpensive, and after pretreatment and modification, it can obtain good adsorption performance, eliminating the need to use expensive special adsorption materials, thereby reducing material costs and solving the high cost problem of existing earthy odor adsorption materials.

[0012] Throughout the preparation process, the silane system, catalyst, silane coupling agent, and nano-titanium dioxide used are all relatively safe, non-toxic, or low-toxic substances, and do not produce harmful residues during use. Compared to some traditional adsorption materials, this modified fiber material does not release other harmful substances after absorbing earthy odors, thus avoiding the risk of secondary contamination.

[0013] During the silane modification process, a stable structure is formed between the disilane system and the fiber material through chemical bonding. This stable chemical bonding makes the active sites and structure on the surface of the fiber material less susceptible to damage during the regeneration process, and can maintain good adsorption performance. Even after multiple regeneration treatments, the adsorption capacity of the fiber material will not show significant attenuation. After being modified with a silane coupling agent, the loaded nano-titanium dioxide is more tightly bonded to the fiber material. During the regeneration process, nano-titanium dioxide is not easy to fall off from the surface of the fiber material or agglomerate, thereby ensuring its adsorption performance after regeneration. In addition, nano-titanium dioxide itself has a certain stability and durability, and can resist the physical and chemical effects of the regeneration process to a certain extent, further slowing down the attenuation of the adsorption capacity. This solves the problem of significant attenuation of the adsorption capacity of existing earthy odor adsorption materials after regeneration.

[0014] Preferably, in S2, the bisilane system is selected from a mixture of octadecyltrimethoxysilane (C18) and γ-methacryloxypropyltrimethoxysilane (KH-570).

[0015] By using a mixture of octadecyltrimethoxysilane (C18) and γ-methacryloxypropyltrimethoxysilane (KH-570) to form a disilane system, not only the hydrophobic properties of the fiber are effectively enhanced, but also the flexibility of the fiber is effectively improved, making it easier for the fiber to adhere to the surface of pollutants (such as oil droplets or particulate matter) during the adsorption process, increasing the effective contact area and thus improving the adsorption efficiency.

[0016] Preferably, the mass ratio of octadecyltrimethoxysilane (C18) to γ-methacryloxypropyltrimethoxysilane (KH-570) in the bisilane system is 1:0.4.

[0017] Preferably, in S2, the catalyst is selected from acetic acid / sodium acetate buffer.

[0018] By adding acetic acid / sodium acetate buffer as a catalyst, the hydrolysis of Si-OC bonds was effectively reduced, and the grafting density was increased by 15%, thereby forming a stable hydrophobic layer.

[0019] Preferably, the pH value of the acetic acid / sodium acetate buffer is 4.5-5.5.

[0020] Preferably, the pH value of the acetic acid / sodium acetate buffer is 5.0.

[0021] Preferably, in S1, the fibers are selected from natural plant fibers.

[0022] Preferably, the natural fiber is a plant fiber, and the plant fiber includes at least one of cotton, kapok, flax, ramie, hemp, jute, sisal, abaca and coconut shell fiber.

[0023] Preferably, in S2, the temperature of the mixed heating reaction is 60-70° C., and the time is 7-9 hours.

[0024] Preferably, the temperature of the mixed heating reaction is 65° C. and the time is 8 hours.

[0025] Preferably, the mixing and heating reaction is a mixing and stirring heating reaction.

[0026] Preferably, in S3, the preparation method of modified nano-titanium dioxide comprises: adding nano-titanium dioxide to a mixture of γ-methacryloxypropyltrimethoxysilane (KH-570) and γ-aminopropyltriethoxysilane (KH-550), adjusting the pH value to 6-7, and then stirring the mixture at a temperature of 70°C for 1-2 hours to obtain modified nano-titanium dioxide.

[0027] By using γ-methacryloxypropyltrimethoxysilane (KH-570) to modify the surface of nano-titanium dioxide and introducing γ-aminopropyltriethoxysilane (KH-550) as an interface enhancer, the silane coupling agent and nano-titanium dioxide are chemically bonded to form a stable Si-O-Ti structure, which effectively enhances the subsequent bonding force with the fiber substrate and effectively ensures the adsorption performance of the fiber recycling.

[0028] Preferably, the amount of the modifier γ-methacryloxypropyltrimethoxysilane (KH-570) is 10% of the mass of titanium dioxide (TiO2).

[0029] Preferably, the amount of the interface enhancer γ-aminopropyltriethoxysilane (KH-550) is 3% of the mass of titanium dioxide (TiO2).

[0030] Preferably, the particle size of the nano-titanium dioxide is 20 nm to 50 nm.

[0031] Preferably, in said S3, the method for preparing the dispersion comprises: adding the modified nano-titanium dioxide to an ethanol aqueous solution, and then adding acetic acid to obtain the dispersion.

[0032] Preferably, in S3, the method for preparing the modified fiber material comprises: immersing the silane-modified fiber in a dispersion, and ultrasonically treating the fiber at room temperature for 1 to 3 hours to obtain the fiber material loaded with nano-titanium dioxide.

[0033] Preferably, the power of ultrasonic treatment is 300 W and the frequency is 40 kHz.

[0034] Ultrasonic treatment during the impregnation process effectively promotes the penetration of nanoparticles into the fiber pores, thereby effectively ensuring the hydrophobicity and chemical adsorption capacity of the modified fiber material. At the same time, the introduction of the interfacial enhancer γ-aminopropyltriethoxysilane (KH-550) allows the silane-modified fiber to undergo a condensation reaction with the hydroxyl groups on the fiber surface during the impregnation process, forming a "fiber-TiO2" gradient bonding layer, further improving the load-bearing firmness.

[0035] Preferably, the step S3 further comprises: subjecting the fiber material loaded with nano-titanium dioxide to vacuum filtration to remove free particles, and then drying the fiber material under vacuum conditions at 60° C. for 12 hours to solidify the modified nano-titanium dioxide layer to obtain a modified fiber material.

[0036] Preferably, the vacuum degree of the vacuum filtration treatment is less than 10 Pa.

[0037] Preferably, in S1, the fiber activation treatment includes: immersing the fiber in an alkaline solution for ultrasonic treatment for 30 minutes, and then immersing the fiber in an acid solution for ultrasonic treatment for 30 minutes to remove metal oxide residues and impurities and increase the hydroxyl exposure points of the fiber material (hydroxyl exposure rate ≥ 90%), and then rinsing the fiber with deionized water to remove residual acid or alkali to obtain activated fiber; Freeze drying includes: pre-freezing the activated fiber at a temperature of -50°C, and then sublimation drying for 12 hours at a vacuum degree of 0.1 Pa to retain the three-dimensional porous structure of the fiber to obtain pretreated fiber.

[0038] Experimental research has shown that freeze-drying can better preserve the microstructure than high-temperature (100°C) drying.

[0039] Preferably, the alkaline solution is selected from a sodium hydroxide (NaOH) solution with a concentration of 5%.

[0040] Preferably, the acid solution is selected from a hydrochloric acid (HCl) solution with a concentration of 1%.

[0041] The present invention also provides a modified fiber material prepared by the method of the present invention.

[0042] The present invention also provides a use of the modified fiber material prepared by the preparation method of the present invention as an adsorbent.

[0043] Preferably, the modified fiber material is used to absorb earthy odor substances in water.

[0044] Preferably, the earthy smelling substances include at least geosmin and 2-methylisoborneol.

[0045] Preferably, the water body includes at least aquaculture water, drinking water source and industrial wastewater.

[0046] Preferably, the adsorption capacity attenuation rate of the modified fiber material after adsorption regeneration is less than 6.7%.

[0047] The method for regenerating the modified fiber material after adsorption comprises the following steps: The modified fiber material adsorbed with the earthy odor substance is placed in a sealed environment combined with ozone and ultraviolet light for treatment, and dried to obtain a regenerated modified fiber material; The modified fiber material is a fiber material that has been modified by silanization and loaded with titanium dioxide; The fiber material is natural plant fiber.

[0048] Through the synergistic effect of ozone and ultraviolet light, ozone is decomposed into OH (oxidation potential 2.8 V) under the action of ultraviolet light, thereby non-selectively attacking geosmin (C 12 H 22 O) of the olefin bond and methyl side chain, •OH can efficiently oxidize the tertiary alcohol structure and methyl side chain in the 2-methylisoborneol molecule to produce small molecular carboxylic acids (such as acetic acid and propionic acid), which are ultimately mineralized into CO2 and H2O, effectively regenerating the modified fiber material adsorbed with earthy odor substances. The nano-TiO2 loaded on the surface of the modified fiber material activates photocatalysis under ultraviolet light and can synergistically degrade pollutants with ozone, further enhancing the regeneration capacity. At the same time, the TiO2 coating prevents excessive ozone oxidation and fiber substrate breakage, ensuring the stability of the regenerated modified fiber material. This solves the problem of significant adsorption capacity decay after regeneration of existing earthy odor adsorbent materials.

[0049] The combined ozone and UV treatment not only removes earthy odors but also removes other impurities and contaminants from the fiber surface. These impurities may occupy active sites on the fiber during the adsorption process, affecting its adsorption performance. This regeneration method restores the active sites on the fiber surface, allowing it to regain efficient adsorption capacity. Furthermore, the relatively mild ozone and UV treatment conditions do not damage the fiber's internal structure. After this regeneration process, the natural plant fiber retains its three-dimensional porous structure, providing excellent channels and surface area for adsorption, thereby ensuring the regenerated material's adsorption efficiency. Fiber materials modified with silanization and loaded with titanium dioxide have a stable chemical structure. During the ozone and UV regeneration process, this stable structure resists oxidation, reducing degradation and damage to the fiber. Therefore, even after multiple regeneration treatments, the fiber's adsorption capacity does not show significant attenuation. The combined ozone and UV regeneration method effectively restores the fiber's adsorption properties, allowing it to maintain a high adsorption capacity after repeated use. Compared with traditional regeneration methods (such as thermal regeneration, chemical regeneration, etc.), this method can significantly reduce the attenuation of adsorption capacity and extend the service life of the material.

[0050] Furthermore, ozone decomposes in water to produce oxygen, and the UV treatment process produces no harmful chemical residues. This regeneration method does not cause secondary pollution to the environment and conforms to the principles of green chemistry. The combined ozone and UV regeneration process takes place at room temperature and pressure, eliminating the need for harsh conditions such as high temperature and pressure, resulting in lower energy consumption. This not only reduces regeneration costs but also improves the economic efficiency of the regeneration process.

[0051] Preferably, the ozone concentration in the sealed environment is 1-10 mg / L.

[0052] Preferably, in the sealed environment, the wavelength of the ultraviolet light is 254 nm, the power is 30-100 W, and the irradiation intensity is 10-15 mW / cm 2 , ultraviolet radiation coverage is greater than 90%.

[0053] Preferably, in the sealed environment, ozone is evenly distributed through microporous aeration tubes, and ultraviolet lamps are arranged in a spiral to enhance light radiation coverage.

[0054] Preferably, the treatment time in the sealed environment is 20 minutes.

[0055] Preferably, the drying is: hot air drying the regenerated modified fiber material at a temperature of 60-80°C.

[0056] Preferably, the adsorption capacity attenuation rate of the regenerated modified fiber material obtained after 10 cycles of adsorption regeneration of the modified fiber material is less than 6.7%.

[0057] Beneficial effects of the present invention: The method for preparing the modified fiber material of the present invention firstly activates the fibers to increase the number of exposed hydroxyl groups, thereby providing more "anchor points" for the adsorption process. This allows earthy-smelling substances to more effectively bind to the fiber material, improving adsorption efficiency. Secondly, freeze-drying preserves more of the fiber's three-dimensional porous structure, providing a favorable channel for the diffusion and adsorption of earthy-smelling substances. The porous structure increases the specific surface area of the fiber material, allowing more fiber surface to come into contact with the earthy-smelling substances. Furthermore, the pores within the porous structure can accommodate earthy-smelling substance molecules, promoting their diffusion and adsorption within the fiber material, further improving adsorption efficiency. Thirdly, during the loading process, nano-titanium dioxide modified with a silane coupling agent is loaded onto the silane-modified fibers, further enhancing the modified fiber material's adsorption capacity for earthy-smelling substances. Furthermore, during the silane modification process, chemical bonding between the disilane system and the fiber material forms a stable structure. This stable chemical bonding prevents the active sites and structure on the fiber material from being damaged during regeneration, maintaining good regeneration adsorption performance. It also has the advantages of a wide range of raw material sources, relatively low prices, relatively simple operation, mild reaction conditions and low risk of secondary pollution.

[0058] Experimental research has shown that the modified fiber material of the present invention has good adsorption performance for earthy odor substances in water (such as geosmin, 2-methylisoborneol, etc.), and the regeneration cycle adsorption capacity attenuation rate is very low, which meets the needs of sustainable development and has promotion and application value in the field of water treatment technology. DETAILED DESCRIPTION

[0059] The following will describe the embodiments of the present invention with reference to preferred embodiments. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are intended only to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0060] Example 1 A method for preparing a modified fiber material comprises the following steps: S1. Preprocessing: S11. Activation of substrate: Immersing cotton in a 5% sodium hydroxide solution and ultrasonically treating it for 30 minutes, then immersing it in a 1% hydrochloric acid solution and ultrasonically treating it for 30 minutes to remove metal oxide residues and impurities, and then rinsing the fiber with deionized water to remove residual acid or alkali, thereby obtaining activated fiber; S12, freeze drying: pre-freeze the activated fiber obtained in S11 at a temperature of -50°C, and then sublimate and dry it at a vacuum degree of 0.1 Pa for 12 hours to retain the three-dimensional porous structure of the fiber, thereby obtaining a pretreated fiber; S2, Silane modification: S21. Preparing a bissilane system: mixing octadecyltrimethoxysilane (C18) and γ-methacryloxypropyltrimethoxysilane (KH-570) at a mass ratio of 1:0.4 to obtain a bissilane system; S22, modification: 10 g of the pretreated fiber obtained in S12, 6 g of the disilane system obtained in S21, and 12 mL of acetic acid / sodium acetate buffer (pH = 5.0) were mixed and stirred at 65 °C for 8 h to obtain silane-modified fiber; S3, load: S31. Preparation of modified nano-titanium dioxide: Add nano-titanium dioxide to a mixture of γ-methacryloxypropyltrimethoxysilane (KH-570) and γ-aminopropyltriethoxysilane (KH-550), adjust the pH value of the system to 6.5 with 1.0 mol / L hydrochloric acid, and then react at 70°C with constant stirring for 1.5 hours to allow the coupling agent to form a stable Si-O-Ti structure through chemical bonding, thereby enhancing the bonding strength with the fiber substrate, thereby obtaining modified nano-titanium dioxide; wherein the amount of KH-570 is 10% of the mass of the nano-titanium dioxide; the amount of KH-550 is 3% of the mass of the nano-titanium dioxide; S32, preparing a dispersion: dispersing the modified nano-titanium dioxide obtained in S31 in an ethanol aqueous solution to a concentration of 2%, and then adding 0.1 mol / L acetic acid as a catalyst to obtain a dispersion; wherein the volume ratio of ethanol to water in the ethanol aqueous solution is 8:2; S33, titanium dioxide loading: The silane-modified fiber obtained in S22 was immersed in the dispersion prepared in S32, and subjected to ultrasonic-assisted treatment at a power of 300 W and a frequency of 40 kHz for 2 h to promote the penetration of nanoparticles into the fiber pores, thereby obtaining a fiber material loaded with nano-titanium dioxide; S34. Post-treatment: The fiber material loaded with nano-titanium dioxide is subjected to vacuum filtration treatment at a vacuum degree of less than 10 Pa to remove free particles, and then dried at a vacuum condition of 60° C. for 12 hours to solidify the titanium dioxide coating to obtain a modified fiber material.

[0061] Example 2 A method for preparing a modified fiber material comprises the following steps: S1. Preprocessing: S11. Activation of substrate: Immerse the kapok in a 5% sodium hydroxide solution and ultrasonically treat for 30 minutes, then immerse it in a 1% hydrochloric acid solution and ultrasonically treat for 30 minutes to remove metal oxide residues and impurities, and then rinse the fiber with deionized water to remove residual acid or alkali to obtain activated fiber; S12, freeze drying: pre-freeze the activated fiber obtained in S11 at a temperature of -50°C, and then sublimate and dry it at a vacuum degree of 0.1 Pa for 12 hours to retain the three-dimensional porous structure of the fiber, thereby obtaining a pretreated fiber; S2, Silane modification: S21. Preparing a bissilane system: mixing octadecyltrimethoxysilane (C18) and γ-methacryloxypropyltrimethoxysilane (KH-570) at a mass ratio of 1:0.4 to obtain a bissilane system; S22, modification: 10 g of the pretreated fiber obtained in S12, 6 g of the disilane system obtained in S21, and 12 mL of acetic acid / sodium acetate buffer (pH = 5.0) were mixed and stirred at 65 °C for 8 h to obtain silane-modified fiber; S3, load: S31. Preparation of modified nano-titanium dioxide: Add nano-titanium dioxide to a mixture of γ-methacryloxypropyltrimethoxysilane (KH-570) and γ-aminopropyltriethoxysilane (KH-550), adjust the pH value of the system to 6.5 with 1.0 mol / L hydrochloric acid, and then react at 70°C with constant stirring for 1.5 hours to allow the coupling agent to form a stable Si-O-Ti structure through chemical bonding, thereby enhancing the bonding strength with the fiber substrate, thereby obtaining modified nano-titanium dioxide; wherein the amount of KH-570 is 10% of the mass of the nano-titanium dioxide; the amount of KH-550 is 3% of the mass of the nano-titanium dioxide; S32, preparing a dispersion: dispersing the modified nano-titanium dioxide obtained in S31 in an ethanol aqueous solution to a concentration of 2%, and then adding 0.1 mol / L acetic acid as a catalyst to obtain a dispersion; wherein the volume ratio of ethanol to water in the ethanol aqueous solution is 8:2; S33, titanium dioxide loading: The silane-modified fiber obtained in S22 was immersed in the dispersion prepared in S32, and subjected to ultrasonic-assisted treatment at a power of 300 W and a frequency of 40 kHz for 2 h to promote the penetration of nanoparticles into the fiber pores, thereby obtaining a fiber material loaded with nano-titanium dioxide; S34. Post-treatment: The fiber material loaded with nano-titanium dioxide is subjected to vacuum filtration treatment at a vacuum degree of less than 10 Pa to remove free particles, and then dried at a vacuum condition of 60° C. for 12 hours to solidify the titanium dioxide coating to obtain a modified fiber material.

[0062] Example 3 A method for preparing a modified fiber material comprises the following steps: S1. Preprocessing: S11. Activating the substrate: Immersing the flax in a 5% sodium hydroxide solution and ultrasonically treating it for 30 minutes, then immersing it in a 1% hydrochloric acid solution and ultrasonically treating it for 30 minutes to remove residual metal oxides and impurities, and then rinsing the fiber with deionized water to remove residual acid or alkali, thereby obtaining activated fiber; S12, freeze drying: pre-freeze the activated fiber obtained in S11 at a temperature of -50°C, and then sublimate and dry it at a vacuum degree of 0.1 Pa for 12 hours to retain the three-dimensional porous structure of the fiber, thereby obtaining a pretreated fiber; S2, Silane modification: S21. Preparing a bissilane system: mixing octadecyltrimethoxysilane (C18) and γ-methacryloxypropyltrimethoxysilane (KH-570) at a mass ratio of 1:0.4 to obtain a bissilane system; S22, modification: 10 g of the pretreated fiber obtained in S12, 6 g of the disilane system obtained in S21, and 12 mL of acetic acid / sodium acetate buffer (pH = 5.0) were mixed and stirred at 65 °C for 8 h to obtain silane-modified fiber; S3, load: S31. Preparation of modified nano-titanium dioxide: Add nano-titanium dioxide to a mixture of γ-methacryloxypropyltrimethoxysilane (KH-570) and γ-aminopropyltriethoxysilane (KH-550), adjust the pH value of the system to 6.5 with 1.0 mol / L hydrochloric acid, and then react at 70°C with constant stirring for 1.5 hours to allow the coupling agent to form a stable Si-O-Ti structure through chemical bonding, thereby enhancing the bonding strength with the fiber substrate, thereby obtaining modified nano-titanium dioxide; wherein the amount of KH-570 is 10% of the mass of the nano-titanium dioxide; the amount of KH-550 is 3% of the mass of the nano-titanium dioxide; S32, preparing a dispersion: dispersing the modified nano-titanium dioxide obtained in S31 in an ethanol aqueous solution to a concentration of 2%, and then adding 0.1 mol / L acetic acid as a catalyst to obtain a dispersion; wherein the volume ratio of ethanol to water in the ethanol aqueous solution is 8:2; S33, titanium dioxide loading: The silane-modified fiber obtained in S22 was immersed in the dispersion prepared in S32, and subjected to ultrasonic-assisted treatment at a power of 300 W and a frequency of 40 kHz for 2 h to promote the penetration of nanoparticles into the fiber pores, thereby obtaining a fiber material loaded with nano-titanium dioxide; S34. Post-treatment: The fiber material loaded with nano-titanium dioxide is subjected to vacuum filtration treatment at a vacuum degree of less than 10 Pa to remove free particles, and then dried at a vacuum condition of 60° C. for 12 hours to solidify the titanium dioxide coating to obtain a modified fiber material.

[0063] Example 4 A method for preparing a modified fiber material comprises the following steps: S1. Preprocessing: S11. Substrate activation: immerse the hemp in a 5% sodium hydroxide solution and ultrasonically treat it for 30 minutes, then immerse it in a 1% hydrochloric acid solution and ultrasonically treat it for 30 minutes to remove metal oxide residues and impurities, and then rinse the fiber with deionized water to remove residual acid or alkali to obtain activated fiber; S12, freeze drying: pre-freeze the activated fiber obtained in S11 at a temperature of -50°C, and then sublimate and dry it at a vacuum degree of 0.1 Pa for 12 hours to retain the three-dimensional porous structure of the fiber, thereby obtaining a pretreated fiber; S2, Silane modification: S21. Preparing a bissilane system: mixing octadecyltrimethoxysilane (C18) and γ-methacryloxypropyltrimethoxysilane (KH-570) at a mass ratio of 1:0.4 to obtain a bissilane system; S22, modification: 10 g of the pretreated fiber obtained in S12, 6 g of the disilane system obtained in S21, and 12 mL of acetic acid / sodium acetate buffer (pH = 5.0) were mixed and stirred at 65 °C for 8 h to obtain silane-modified fiber; S3, load: S31. Preparation of modified nano-titanium dioxide: Add nano-titanium dioxide to a mixture of γ-methacryloxypropyltrimethoxysilane (KH-570) and γ-aminopropyltriethoxysilane (KH-550), adjust the pH value of the system to 6.5 with 1.0 mol / L hydrochloric acid, and then react at 70°C with constant stirring for 1.5 hours to allow the coupling agent to form a stable Si-O-Ti structure through chemical bonding, thereby enhancing the bonding strength with the fiber substrate, thereby obtaining modified nano-titanium dioxide; wherein the amount of KH-570 is 10% of the mass of the nano-titanium dioxide; the amount of KH-550 is 3% of the mass of the nano-titanium dioxide; S32, preparing a dispersion: dispersing the modified nano-titanium dioxide obtained in S31 in an ethanol aqueous solution to a concentration of 2%, and then adding 0.1 mol / L acetic acid as a catalyst to obtain a dispersion; wherein the volume ratio of ethanol to water in the ethanol aqueous solution is 8:2; S33, titanium dioxide loading: The silane-modified fiber obtained in S22 was immersed in the dispersion prepared in S32, and subjected to ultrasonic-assisted treatment at a power of 300 W and a frequency of 40 kHz for 2 h to promote the penetration of nanoparticles into the fiber pores, thereby obtaining a fiber material loaded with nano-titanium dioxide; S34. Post-treatment: The fiber material loaded with nano-titanium dioxide is subjected to vacuum filtration treatment at a vacuum degree of less than 10 Pa to remove free particles, and then dried at a vacuum condition of 60° C. for 12 hours to solidify the titanium dioxide coating to obtain a modified fiber material.

[0064] Example 5 A method for preparing a modified fiber material comprises the following steps: S1. Preprocessing: S11, substrate activation: immersing the coconut shell fiber in a 5% sodium hydroxide solution and ultrasonically treating it for 30 minutes, and then immersing it in a 1% hydrochloric acid solution and ultrasonically treating it for 30 minutes to remove metal oxide residues and impurities, and then rinsing the fiber with deionized water to remove residual acid or alkali to obtain activated fiber; S12, freeze drying: pre-freeze the activated fiber obtained in S11 at a temperature of -50°C, and then sublimate and dry it at a vacuum degree of 0.1 Pa for 12 hours to retain the three-dimensional porous structure of the fiber, thereby obtaining a pretreated fiber; S2, Silane modification: S21. Preparing a bissilane system: mixing octadecyltrimethoxysilane (C18) and γ-methacryloxypropyltrimethoxysilane (KH-570) at a mass ratio of 1:0.4 to obtain a bissilane system; S22, modification: 10 g of the pretreated fiber obtained in S12, 6 g of the disilane system obtained in S21, and 12 mL of acetic acid / sodium acetate buffer (pH = 5.0) were mixed and stirred at 65 °C for 8 h to obtain silane-modified fiber; S3, load: S31. Preparation of modified nano-titanium dioxide: Add nano-titanium dioxide to a mixture of γ-methacryloxypropyltrimethoxysilane (KH-570) and γ-aminopropyltriethoxysilane (KH-550), adjust the pH value of the system to 6.5 with 1.0 mol / L hydrochloric acid, and then react at 70°C with constant stirring for 1.5 hours to allow the coupling agent to form a stable Si-O-Ti structure through chemical bonding, thereby enhancing the bonding strength with the fiber substrate, thereby obtaining modified nano-titanium dioxide; wherein the amount of KH-570 is 10% of the mass of the nano-titanium dioxide; the amount of KH-550 is 3% of the mass of the nano-titanium dioxide; S32, preparing a dispersion: dispersing the modified nano-titanium dioxide obtained in S31 in an ethanol aqueous solution to a concentration of 2%, and then adding 0.1 mol / L acetic acid as a catalyst to obtain a dispersion; wherein the volume ratio of ethanol to water in the ethanol aqueous solution is 8:2; S33, titanium dioxide loading: The silane-modified fiber obtained in S22 was immersed in the dispersion prepared in S32, and subjected to ultrasonic-assisted treatment at a power of 300 W and a frequency of 40 kHz for 2 h to promote the penetration of nanoparticles into the fiber pores, thereby obtaining a fiber material loaded with nano-titanium dioxide; S34. Post-treatment: The fiber material loaded with nano-titanium dioxide is subjected to vacuum filtration treatment at a vacuum degree of less than 10 Pa to remove free particles, and then dried at a vacuum condition of 60° C. for 12 hours to solidify the titanium dioxide coating to obtain a modified fiber material.

[0065] Example 6 A method for preparing a modified fiber material comprises the following steps: S1. Preprocessing: S11. Activation of substrate: Immersing cotton in a 5% sodium hydroxide solution and ultrasonically treating it for 30 minutes, then immersing it in a 1% hydrochloric acid solution and ultrasonically treating it for 30 minutes to remove metal oxide residues and impurities, and then rinsing the fiber with deionized water to remove residual acid or alkali, thereby obtaining activated fiber; S12, freeze drying: pre-freeze the activated fiber obtained in S11 at a temperature of -50°C, and then sublimate and dry it at a vacuum degree of 0.1 Pa for 12 hours to retain the three-dimensional porous structure of the fiber, thereby obtaining a pretreated fiber; S2, Silane modification: S21. Preparing a bissilane system: mixing octadecyltrimethoxysilane (C18) and γ-methacryloxypropyltrimethoxysilane (KH-570) at a mass ratio of 1:0.4 to obtain a bissilane system; S22, modification: 10 g of the pretreated fiber obtained in S12, 6 g of the disilane system obtained in S21, and 12 mL of water were mixed and stirred at 65°C for 8 h to obtain silane-modified fiber; S3, load: S31. Preparation of modified nano-titanium dioxide: nano-titanium dioxide is added to a mixture of γ-methacryloyloxypropyltrimethoxysilane (KH-570) and γ-aminopropyltriethoxysilane (KH-550), and the pH value of the system is adjusted to 6.5 with 1.0 mol / L hydrochloric acid. The mixture is then stirred at a constant temperature of 70°C for 1.5 hours to allow the coupling agent to form a stable Si-O-Ti structure through chemical bonding, thereby enhancing the bonding strength with the fiber substrate, thereby obtaining modified nano-titanium dioxide; wherein, the amount of KH-570 is 10% of the mass of the nano-titanium dioxide; the amount of KH-550 is % of the mass of the nano-titanium dioxide; S32, preparing a dispersion: dispersing the modified nano-titanium dioxide obtained in S31 in an ethanol aqueous solution to a concentration of 2%, and then adding 0.1 mol / L acetic acid as a catalyst to obtain a dispersion; wherein the volume ratio of ethanol to water in the ethanol aqueous solution is 8:2; S33, titanium dioxide loading: The silane-modified fiber obtained in S22 was immersed in the dispersion prepared in S32, and subjected to ultrasonic-assisted treatment at a power of 300 W and a frequency of 40 kHz for 2 h to promote the penetration of nanoparticles into the fiber pores, thereby obtaining a fiber material loaded with nano-titanium dioxide; S34. Post-treatment: The fiber material loaded with nano-titanium dioxide is subjected to vacuum filtration treatment at a vacuum degree of less than 10 Pa to remove free particles, and then dried at a vacuum condition of 60° C. for 12 hours to solidify the titanium dioxide coating to obtain a modified fiber material.

[0066] Detection and Analysis 1) Adsorption performance test 4 g of each of the modified fiber materials prepared in Examples 1 to 5 was placed in 2 L of aquaculture wastewater containing geosmin (initial concentration of 60 μg / L) and 2-methylisoborneol (initial concentration of 80 μg / L). After 30 minutes of adsorption, the concentration changes before and after adsorption were determined by headspace solid phase microextraction gas chromatography-mass spectrometry. The results are shown in Table 1.

[0067] Table 1 shows the adsorption results of geosmin and 2-methylisoborneol From the analysis in Table 1, it can be seen that the modified fiber materials prepared in Examples 1 to 5 have removal rates of 71.3% to 72.8% and 64% to 66% for geosmin and 2-methylisoborneol, respectively, and have good adsorption properties.

[0068] 2) Adsorption performance test after regeneration 4 g of the modified fiber materials prepared in Examples 1 to 5 were respectively placed in 2 L of aquaculture wastewater with a geosmin concentration of 60 μg / L and a 2-methylisoborneol concentration of 80 μg / L for adsorption for 30 minutes to obtain a modified fiber material that was first adsorbed with geosmin and 2-methylisoborneol. The modified fiber material that was first adsorbed with geosmin and 2-methylisoborneol was placed in a sealed cavity combined with ozone and ultraviolet light for treatment for 20 minutes, and then the regenerated modified fiber material was hot-air dried at a temperature of 70°C to obtain a first regenerated modified fiber material. The adsorption and regeneration cycle was repeated 10 times to obtain a tenth regenerated modified fiber material.

[0069] Among them, ozone is evenly distributed in the sealed cavity through the microporous aeration tube, and the ultraviolet lamp is evenly arranged in a spiral. The concentration of ozone in the sealed cavity is 5mg / L, the wavelength of the ultraviolet light is 254nm, the power is 60W, and the irradiation intensity is 12mW / cm 2 .

[0070] 4 g of the 10th regenerated modified fiber material obtained after 10 adsorption regeneration cycles of the modified fiber material prepared in Examples 1 to 5 was placed in 2 L of aquaculture wastewater containing geosmin (initial concentration of 60 μg / L) and 2-methylisoborneol (initial concentration of 80 μg / L). After adsorption for 30 minutes, the concentration changes before and after adsorption were determined by headspace solid phase microextraction gas chromatography-mass spectrometry. The results are shown in Table 2.

[0071] Table 2 shows the adsorption and capacity attenuation results of the 10th regenerated modified fiber materials in Examples 1 to 5. The number 10 in Table 2 represents the regenerated modified fiber material after 10 adsorption regeneration cycles of the modified fibers in Examples 1 to 5. Analysis in Table 2 indicates that the modified fiber materials in Examples 1 to 5 exhibited good removal rates for geosmin and 2-methylisoborneol after 10 adsorption regeneration cycles, and the adsorption capacity decay rate (%) after 10 adsorption regeneration cycles was less than 6.7%, demonstrating excellent cyclic adsorption stability.

[0072] 3) Si-OC bond hydrolysis rate, grafting density and contact angle test The modified fiber materials obtained in Example 1 and Example 6 were respectively 29 The hydrolysis rate of Si-OC bonds was quantitatively determined by Si NMR, the grafting density was determined by XPS, and the contact angle was measured by static method (seating drop method). The results are shown in Table 3.

[0073] Table 3 shows the test results of Si-OC bond hydrolysis rate, grafting density and contact angle of modified fiber materials As shown in Table 3, the Si-OC hydrolysis rate of the modified fiber material prepared by adding acetic acid / sodium acetate was reduced by 44%. XPS measurement results showed that the C / Si atomic ratio of the modified fiber material prepared by adding water was 0.8, while the C / Si atomic ratio of the modified fiber material prepared by adding acetic acid / sodium acetate was 0.92. Therefore, the grafting density of the modified fiber material prepared by adding acetic acid / sodium acetate was increased by 15% compared with the modified fiber material prepared by adding water. The contact angle of the modified fiber material prepared by adding acetic acid / sodium acetate was 120°, while the contact angle of the modified fiber material prepared by adding water was 105°, which proved that the reduced Si-OC hydrolysis rate allowed the water transport chain of the modified fiber material to be more intact. From the above, it can be seen that the weak acidity of the acetic acid / sodium acetate buffer effectively inhibited the excessive hydrolysis of the Si-OC bond, while promoting the condensation reaction, reducing hydrolysis and making the hydrophobic chain (C18) more evenly distributed, thereby enhancing the mechanical stability of the modified fiber material.

[0074] In summary, the modified fiber material of the present invention increases the number of exposed hydroxyl groups in the fiber material by subjecting it to an activation treatment, thereby providing more "anchor points" for the adsorption process. This allows earthy-smelling substances to more effectively bind to the fiber material, improving adsorption efficiency. Secondly, after freeze-drying, more of the fiber's three-dimensional porous structure is retained, providing a favorable channel for the diffusion and adsorption of earthy-smelling substances. This porous structure increases the specific surface area of the fiber material, allowing more of the fiber surface to come into contact with the earthy-smelling substances. Furthermore, the pores within the porous structure can accommodate earthy-smelling substance molecules, promoting their diffusion and adsorption within the fiber material, further improving adsorption efficiency. Thirdly, during the loading process, nano-titanium dioxide modified with a silane coupling agent is loaded onto the silane-modified fiber, further enhancing the modified fiber material's adsorption capacity for earthy-smelling substances. Furthermore, during the silane modification process, the disilane system forms a stable structure with the fiber material through chemical bonding. This stable chemical bonding prevents the active sites and structure on the fiber material from being damaged during regeneration, maintaining good regeneration adsorption performance. The process also offers advantages such as a wide range of raw material sources, relatively low prices, simple operation, mild reaction conditions, and a low risk of secondary pollution. Experimental research has shown that it has excellent adsorption properties for earthy-smelling substances in water (such as geosmin and 2-methylisoborneol), with a very low rate of adsorption capacity decay during regeneration cycles. This meets the needs of sustainable development and has potential for widespread application in the field of water treatment technology.

[0075] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A method for preparing a modified fiber material, characterized in that: The following steps are involved: S1. Pretreatment: Activate the fiber and freeze-dry to obtain pretreated fiber; S2, silane modification: pretreated fiber, bisilane system and catalyst are mixed and heated to react to obtain silane-modified fiber; S3, loading: using silane coupling agent to modify nano titanium dioxide (TiO2) to obtain modified nano titanium dioxide; The modified nano-titanium dioxide is dispersed in a solvent to obtain a dispersion liquid; the silane-modified fiber is immersed in the dispersion liquid and solidified to obtain a modified fiber material.

2. The method for preparing a modified fiber material according to claim 1, wherein: In said S2, the bisilane system is selected from a mixture of octadecyltrimethoxysilane (C18) and γ-methacryloxypropyltrimethoxysilane (KH-570); And / or, in said S2, the catalyst is selected from acetic acid / sodium acetate buffer; And / or, in S1, the fiber is selected from natural plant fibers.

3. The method for preparing a modified fiber material according to claim 1, characterized in that: In S2, the temperature of the mixed heating reaction is 60-70° C. and the time is 7-9 hours.

4. The method for preparing a modified fiber material according to claim 1, wherein: In S3, the preparation method of modified nano-titanium dioxide comprises: adding nano-titanium dioxide to a mixture of γ-methacryloxypropyltrimethoxysilane (KH-570) and γ-aminopropyltriethoxysilane (KH-550), adjusting the pH value to 6-7, and then stirring the mixture at a temperature of 70° C. for 1-2 hours to obtain modified nano-titanium dioxide; And / or, in said S3, the method for preparing the dispersion comprises: dissolving the modified nano-titanium dioxide in an ethanol aqueous solution, and then adding acetic acid to obtain a dispersion; And / or, in S3, the method for preparing the modified fiber material comprises: immersing the silane-modified fiber in a dispersion solution, and ultrasonically treating the fiber at room temperature for 1 to 3 hours to obtain a fiber material loaded with nano-titanium dioxide; The method further comprises: subjecting the fiber material loaded with nano-titanium dioxide to vacuum filtration treatment, and then drying it under vacuum conditions at a temperature of 60° C. for 12 hours to solidify the modified nano-titanium dioxide layer to obtain a modified fiber material.

5. The method for preparing a modified fiber material according to claim 1, wherein: In S1, the fiber activation treatment includes: immersing the fiber in an alkaline solution for ultrasonic treatment, and then immersing the fiber in an acid solution for ultrasonic treatment to obtain activated fiber; Freeze drying includes: pre-freezing the activated fiber at a temperature of -50°C, and then sublimation drying for 12 hours at a vacuum degree of 0.1 Pa to obtain pre-treated fiber; The alkaline solution is selected from a sodium hydroxide (NaOH) solution having a concentration of 5%; The acid solution is selected from a hydrochloric acid (HCl) solution with a concentration of 1%.

6. A modified fiber material, characterized in that: The method is as described in any one of claims 1 to 5.

7. Use of the modified fiber material obtained by the preparation method according to any one of claims 1 to 5 as an adsorbent.

8. The use according to claim 7, characterized in that The modified fiber material is used for absorbing earthy smell substances in water.

9. The use according to claim 8, characterized in that The earthy smell substances at least include geosmin and 2-methylisoborneol.

10. The use according to claim 8, characterized in that The adsorption capacity attenuation rate of the modified fiber material after adsorption regeneration is less than 6.7%.

Images