Method for directly preparing chitin nanofiber from shrimp and crab shells based on deep eutectic solvent system and chitin nanofiber
By combining a eutectic solvent system and ultrasonic treatment, a simplified preparation of chitin nanofibers was achieved, solving the problems of complex processes, high energy consumption, and serious pollution in traditional methods. This improved the yield and product quality, making it suitable for the fields of biomedicine and food packaging.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- GULF (FOSHAN) BIOTECHNOLOGY CO LTD
- Filing Date
- 2026-03-31
- Publication Date
- 2026-05-12
AI Technical Summary
Existing methods for preparing chitin nanofibers are cumbersome, energy-intensive, cause serious environmental pollution, have low yields, and produce unstable product quality, making industrialization difficult.
By employing a eutectic solvent system, deproteinization, demineralization, and nanoforming are achieved simultaneously in the same reaction. Combined with ultrasonic treatment, this method simplifies the preparation of chitin nanofibers into a one-step process.
It significantly shortens the production cycle, reduces energy consumption, reduces environmental pollution, improves productivity and product quality, simplifies equipment requirements, and broadens the scope of applications.
Smart Images
Figure CN122013369A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of biomass nanomaterial preparation, and mainly to a method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system, and the chitin nanofibers themselves. Background Technology
[0002] Chitin is a natural polymer material widely found in the shells of crustaceans such as shrimp and crab. It has excellent biocompatibility, biodegradability and bioactivity. Its nano-product—chitin nanofibers—continues these core advantages and has broad application prospects in many fields such as biomedicine, food, cosmetics and environmental protection. It has also become a key direction for current chitin application research.
[0003] Traditional methods for preparing chitin nanofibers typically involve three core steps: first, deproteinization, which involves treating shrimp and crab shells with acid or alkali solutions to remove the protein components; second, demineralization, which involves stripping the shells of minerals, primarily calcium carbonate, using strong acid solutions; and third, nanofiberization, which involves further refining chitin microfibers into nanofibers through mechanical grinding, high-pressure homogenization, or chemical treatment.
[0004] Although such methods can successfully prepare chitin nanofibers, several prominent problems remain: the preparation process is cumbersome, requiring multiple independent operations, which not only prolongs the production cycle but also significantly increases production costs; at the same time, the reaction conditions are relatively harsh, with each step requiring high temperature and high pressure environments, resulting in high energy consumption, which does not meet the current development needs for energy conservation and emission reduction; in addition, there is significant environmental pressure, as the preparation process requires the use of large amounts of strong acids and alkalis, generating large amounts of wastewater and waste residue, with high subsequent treatment costs and the potential to cause serious pollution to the ecological environment; furthermore, the product yield is low, and the multi-step operation causes a large loss of chitin; in addition, the product quality stability is insufficient, as the complex multi-step operation can easily damage the molecular structure of chitin, thereby affecting its core product performance such as bioactivity.
[0005] Therefore, developing efficient, energy-saving, environmentally friendly preparation methods that can improve yield and product quality is crucial for promoting the industrialization of chitin nanofibers and fully realizing their application value. Summary of the Invention
[0006] In view of the shortcomings of the prior art, the purpose of this application is to provide a method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system, and the chitin nanofibers themselves. The aim is to simultaneously realize the three processes of deproteinization, demineralization and chitin nanofiber formation in the same reaction system, simplify the process flow, reduce energy consumption and environmental pollution, and improve the yield and quality of chitin nanofibers.
[0007] The technical solution of this application is as follows: A method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system includes the following steps: A eutectic solvent system was prepared by mixing hydrogen bond donors and hydrogen bond acceptors in a molar ratio of 1:1 to 3:1. Shrimp and crab shell powder reacts with the eutectic solvent system at a reaction temperature of 40-100℃, a reaction time of 2-6h, and a stirring rate of 200-500r / min. Then perform the first ultrasonic treatment; the conditions for the first ultrasonic treatment are: ultrasonic power 800-2400W, ultrasonic frequency 20-25kHz, pulse ultrasonic mode with ultrasonic 2s-5s and interval 2s-4s, control system temperature <70℃, and total ultrasonic time 30min-180min. After the reaction was completed, chitin nanofibers were obtained by separation, washing, and a second ultrasonic treatment.
[0008] Furthermore, the conditions for the second ultrasound treatment are the same as those for the first ultrasound treatment.
[0009] Furthermore, the mass ratio of the shrimp and crab shell powder to the eutectic solvent system is 1:(8-20).
[0010] Furthermore, the hydrogen bond donor includes one or more of lactic acid, citric acid, acetic acid, formic acid, and malic acid; the hydrogen bond acceptor includes quaternary ammonium compounds.
[0011] Furthermore, the quaternary ammonium salt compounds include choline chloride and betaine.
[0012] Furthermore, using fresh shrimp and crab shells as raw materials, the mud, sand, meat residue and impurities attached to the surface are removed, and after being rinsed clean with water, they are dried at low temperature to constant weight to obtain the shrimp and crab shell powder.
[0013] Furthermore, the temperature for the low-temperature drying is 60-80℃.
[0014] Furthermore, after being dried at a low temperature to a constant weight, it is then pulverized into a 100-200 mesh powder to obtain the shrimp and crab shell powder.
[0015] Furthermore, the hydrogen bond acceptor is choline chloride, and the hydrogen bond donor is lactic acid.
[0016] Furthermore, the yield of the chitin nanofibers is 86-92%, and the purity is 95-99%.
[0017] This application also provides a chitin nanofiber with a diameter of 20-60 nm.
[0018] Compared with the prior art, this application has the following beneficial effects: 1. Simplified process flow: The traditional three-step method is simplified into a one-step method, which shortens the production cycle by more than 50%. The traditional method requires more than 2 days to prepare the product, while the entire process of this invention only takes 6-12 hours. 2. Reduced energy consumption: Compared with traditional methods, the strong acid desalting and strong alkali deproteinization steps are omitted, which greatly reduces energy consumption; 3. Reduced environmental pollution: The elimination of strong acids and alkalis significantly reduces environmental pollution; 4. Increased yield: The yield of chitin nanofibers can reach over 85%. Attached Figure Description
[0019] Figure 1 This is a microscopic morphology image of chitin nanofibers prepared under the conditions of stirring time of 6 hours and sonication for 30 minutes in Example 1 of this application.
[0020] Figure 2 This is a microscopic morphology image of the chitin product prepared in Comparative Example 1 of this application. Detailed Implementation
[0021] This application provides a method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system, and the chitin nanofibers themselves. To make the objectives, technical solutions, and effects of this application clearer and more explicit, the following provides a more detailed description. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.
[0022] The method provided in this application can be used on shrimp and crab shells, or on shrimp or crab shells alone.
[0023] This application provides a method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system, comprising the following steps: Step 1: Shrimp and crab shell pretreatment: Fresh shrimp and crab shells are selected as raw materials. First, the mud, sand, meat residue and impurities attached to the surface are removed. After being rinsed with clean water, they are dried at a low temperature (temperature controlled at 60-80℃) until constant weight is achieved. Then, they are pulverized into 100-200 mesh powder by a pulverizing device to obtain shrimp and crab shell powder.
[0024] The aim is to increase the contact area between the shrimp and crab shells and the eutectic solvent system, laying the foundation for subsequent simultaneous reactions and ensuring that the reaction proceeds fully.
[0025] Step 2: Reaction in the eutectic solvent system: The pretreated shrimp and crab shell powder was added to a pre-prepared eutectic solvent system and placed in a reaction vessel. The mixture was stirred and reacted under optimized mild reaction conditions. Through the action of the eutectic solvent system and with the aid of the first ultrasonic treatment, the degradation and removal of proteins, the dissolution and stripping of minerals, and the nano-sizing of chitin microfibers in the shrimp and crab shells were completed simultaneously.
[0026] The first ultrasonic treatment used a probe-type ultrasonic disruptor with an ultrasonic power of 800-2400W, an ultrasonic frequency of 20-25kHz, and a pulse ultrasonic mode of 2s-5s with an interval of 2s-4s. The system temperature was controlled to be <70℃, and the total ultrasonic time was 30min-180min.
[0027] This step is the core reaction step of the present invention, achieving a technological breakthrough of "multiple effects in one step".
[0028] Preferably, the mass ratio of shrimp and crab shell powder to the eutectic solvent system is 1:(8-20).
[0029] Mild reaction conditions are as follows: reaction temperature controlled at 40-100℃, reaction time 2-6h, and stirring rate 200-500r / min.
[0030] Specifically, in eutectic solvent systems: Function: As the core reaction medium in the entire preparation process, it can not only provide a stable reaction environment for the three reactions of deproteinization, demineralization and chitin nano-sizing, but also, through its unique solubility, it can target the proteins, minerals and chitin in shrimp and crab shells to achieve simultaneous treatment of the three, replacing the strong acids and alkalis in traditional processes and reducing environmental pollution from the source.
[0031] Implementation method: It is prepared by mixing hydrogen bond donors and hydrogen bond acceptors in a molar ratio of 1:1 to 3:1. The hydrogen bond donors can be one or more of lactic acid, citric acid, acetic acid, formic acid, and malic acid, and the hydrogen bond acceptors can be quaternary ammonium salt compounds such as choline chloride and betaine. The hydrogen bond donors and hydrogen bond acceptors can form a homogeneous and stable eutectic solvent system, and the ratio of the two can be flexibly adjusted according to the characteristics of shrimp and crab shell raw materials to optimize the reaction effect.
[0032] Technical benefits: It completely eliminates the use of strong acids and alkalis in traditional processes, avoids the generation of large amounts of wastewater and waste residue, reduces environmental treatment costs, and the low eutectic solvent system has good biocompatibility, which is in line with the development trend of green chemical industry.
[0033] Regarding simultaneous multi-process reactions: Function: Breaking the barrier of the three independent operations of deproteinization, demineralization and nano-sizing in the traditional preparation process, it completes the three key processes simultaneously in the same eutectic solvent reaction system, without the need to frequently change the reaction device and reaction medium, and realizes the "one-step preparation" of chitin nanofibers.
[0034] Implementation method: By precisely optimizing the reaction conditions, including the reaction temperature (controlled at 40-100℃), reaction time (2-6h), and stirring rate (200-500r / min), the eutectic solvent system can simultaneously dissolve proteins, exfoliate minerals, and refine chitin microfibers. In the eutectic solvent system, proteins are degraded and dissolved, minerals (mainly calcium carbonate) react gently with the solvent and dissolve, and chitin microfibers are gradually exfoliated and refined under the action of the solvent. Finally, the chitin nanofibers are further exfoliated by ultrasound, ultimately forming nanofibers.
[0035] Technical benefits: It significantly simplifies the preparation process, integrates the multi-step operation of the traditional process into a one-step reaction, shortens the production cycle (more than 50% shorter than the traditional process), reduces the number of operation steps, reduces human error, and improves production efficiency, making it possible for the large-scale production of chitin nanofibers.
[0036] Regarding mild reaction conditions: Function: It achieves efficient deproteinization, demineralization and nano-sizing reactions under relatively low temperature and normal pressure conditions, avoiding the damage to the chitin molecular structure caused by high temperature and high pressure in traditional processes, while reducing energy consumption.
[0037] Implementation method: Fully utilize the unique solubility and reactivity of the eutectic solvent system, so that the reaction can proceed smoothly at a mild temperature of 40-100℃; at the same time, the reaction can be completed under normal pressure, eliminating the need for high-pressure reaction vessels, simplifying equipment requirements and reducing equipment investment costs.
[0038] Technical benefits: It significantly reduces energy consumption during the production process and saves production costs; at the same time, the mild reaction environment effectively avoids the breakage and structural damage of chitin molecular chains, maximizing the preservation of chitin's inherent biocompatibility, biodegradability and bioactivity, improving the product quality and stability of chitin nanofibers, and broadening its application scope in various fields.
[0039] Step 3: Product separation and purification: After the reaction was completed, the solid product in the reaction system was separated from the eutectic solvent system by centrifugation (speed controlled at 8000-10000 r / min); then the solid product was repeatedly washed with deionized water until the washing solution was neutral, and then the chitin was further fibroinated by a second ultrasonic treatment to obtain purified chitin nanofibers.
[0040] The parameters for the second ultrasound treatment can be the same as or different from those for the first ultrasound treatment, but it is preferable to use the same parameters.
[0041] The present application will be further described below through specific embodiments.
[0042] Example 1 This embodiment is applicable to the large-scale industrial production of chitin nanofibers, which can be used in fields such as biomedicine and food packaging.
[0043] The method provided in this embodiment can be used for shrimp and crab shells, or for shrimp shells or crab shells alone. This embodiment uses shrimp shells as an example.
[0044] Step 1: Shrimp shell pretreatment: Wash the fresh shrimp shells to remove the mud, sand, meat residue and impurities attached to the surface. After rinsing with clean water, dry them at a low temperature (temperature controlled at 70℃) until constant weight, and then pulverize them to 200 mesh to obtain shrimp shell powder.
[0045] Step 2: Preparation of eutectic solvent system: Choline chloride (hydrogen bond acceptor) and lactic acid (hydrogen bond donor) are mixed in a molar ratio of 1:2 and stirred at 80°C until completely dissolved to obtain eutectic solvent system.
[0046] Step 3: Simultaneous reaction: Add 100g of pretreated shrimp shell powder and eutectic solvent system to the reaction vessel at a mass ratio of 1:10. Stir at 300rpm at 100℃ for 2-6 hours, and then perform the first ultrasonic treatment for 30-120 minutes to simultaneously achieve deproteinization, demineralization and chitin nano-sizing.
[0047] The ultrasonic power is 960W, the ultrasonic frequency is 20kHz, the pulsed ultrasonic mode is 4s of ultrasound followed by 2s of intermittent ultrasound, and the system temperature is controlled to be <70℃.
[0048] The specific parameters for stirring reaction time and ultrasonic treatment time are detailed in Table 1.
[0049] Step 4: Product separation and purification: After the reaction was completed, the reaction mixture was cooled to room temperature, diluted with deionized water, and then centrifuged at 8000 rpm for 10 min to collect the precipitate. The precipitate was repeatedly washed with deionized water until neutral, and then subjected to a second ultrasonic treatment under the same conditions for 30 min to obtain chitin nanofibers.
[0050] Determination of chitin content in shrimp shells: Add 100g of shrimp shell powder to 10 times its weight of 1% hydrochloric acid solution and treat at room temperature for 8 hours. Repeat twice.
[0051] The solution was then treated twice with a 4% sodium hydroxide solution at 80°C for 4 hours each time, with a solid-liquid ratio of 1:10.
[0052] Rinse with water until neutral after each treatment.
[0053] The obtained chitin was dried in an oven at 60°C and weighed to obtain 26.45g of chitin.
[0054] Results: As shown in Table 1, the yield and purity of chitin nanofibers increased with increasing stirring and sonication time. Scanning electron microscopy revealed that the diameters of the chitin nanofibers were all between 20 and 60 nm. The entire process of preparing chitin nanofibers from shrimp shell powder took 6–11.5 hours.
[0055] Table 1. Yield and purity of chitin nanofibers obtained with different stirring and sonication times.
[0056] Example 2 Steps 1 and 2: Same as in Example 1 Step 3: Simultaneous reaction: Add 100g of pretreated shrimp shell powder and eutectic solvent system to the reaction vessel at mass ratios of 1:12, 1:15 and 1:20 respectively (see Table 2 for details). Stir at 300rpm for 6 hours at 100℃, and then perform the first ultrasonic treatment for 30 minutes to simultaneously achieve deproteinization, demineralization and chitin nano-sizing.
[0057] The ultrasonic power is 960W, the ultrasonic frequency is 20kHz, the pulsed ultrasonic mode is 4s of ultrasound followed by 2s of intermittent ultrasound, and the system temperature is controlled to be <70℃.
[0058] Step 4: Same as Example 1.
[0059] Results: As shown in Table 2, the yield of chitin nanofibers decreased slightly with the increase of the material-liquid ratio, but the purity increased.
[0060] Table 2. Yield and purity of chitin nanofibers obtained with different feed-to-liquid ratios.
[0061] Comparative Example 1 Steps 1 and 2: Same as in Example 1 Step 3: Simultaneous reaction: Add 100g of pretreated shrimp shell powder and eutectic solvent system to the reactor at a mass ratio of 1:10, and stir at 300rpm for 6h at 100℃.
[0062] Step 4: Product separation and purification: After the reaction is complete, the reaction mixture is cooled to room temperature, diluted with deionized water, and then centrifuged at 8000 rpm for 10 min to collect the precipitate. The precipitate is washed repeatedly with deionized water until neutral to obtain the chitin product.
[0063] Results: Chitosan nanofibers could not be obtained, and the product remained in powder form. A total of 24.3g of chitosan product was obtained with a purity of 92.4%.
[0064] As can be seen from Example 1 and Comparative Example 1, although deproteinization and demineralization can be completed and purified chitin can be obtained by using only a eutectic solvent system without introducing ultrasonic action, it is difficult to achieve efficient dissociation and nanofiberization of microfibers. The resulting product is mainly particles and chitin nanofibers cannot be obtained.
[0065] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of this application.
Claims
1. A method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system, characterized in that, Includes the following steps: A eutectic solvent system was prepared by mixing hydrogen bond donors and hydrogen bond acceptors in a molar ratio of 1:1 to 3:
1. Shrimp and crab shell powder reacts with the eutectic solvent system at a reaction temperature of 40-100℃, a reaction time of 2-6h, and a stirring rate of 200-500r / min. Perform the first ultrasonic treatment; the conditions for the first ultrasonic treatment are: ultrasonic power 800-2400W, ultrasonic frequency 20-25kHz, pulse ultrasonic mode with 2s-5s ultrasonic and 2s-4s interval, control system temperature <70℃, and total ultrasonic time 30min-180min. After the reaction was completed, chitin nanofibers were obtained by separation, washing, and a second ultrasonic treatment.
2. The method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system according to claim 1, characterized in that, The mass ratio of the shrimp and crab shell powder to the eutectic solvent system is 1:(8-20).
3. The method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system according to claim 1, characterized in that, The conditions for the second ultrasound treatment are the same as those for the first ultrasound treatment.
4. The method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system according to claim 1, characterized in that, The hydrogen bond donor includes one or more of lactic acid, citric acid, acetic acid, formic acid, and malic acid; the hydrogen bond acceptor includes quaternary ammonium compounds.
5. The method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system according to claim 4, characterized in that, The quaternary ammonium salt compounds include choline chloride and betaine.
6. The method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system according to claim 1, characterized in that, Fresh shrimp and crab shells are used as raw materials. After removing the mud, sand, meat residue and impurities attached to the surface, the shells are rinsed with clean water and then dried at low temperature to constant weight to obtain the shrimp and crab shell powder.
7. The method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system according to claim 6, characterized in that, The temperature for the low-temperature drying is 60-80℃.
8. The method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system according to claim 6, characterized in that, After being dried at low temperature to constant weight, the shells are then pulverized to a powder of 100-200 mesh to obtain the shrimp and crab shell powder.
9. Chitin nanofibers prepared by a method for directly preparing chitin nanofibers from shrimp and crab shells based on a eutectic solvent system as described in any one of claims 1-8.
10. The chitin nanofibers according to claim 9, characterized in that, The diameter is 20-60nm.