Modified wheat bran fiber and preparation and use thereof
By treating wheat bran fiber with ultra-high pressure and chemical modification, the problem of insufficient adsorption capacity in dye wastewater treatment was solved, achieving efficient and low-cost dye wastewater treatment.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- XUCHANG UNIV
- Filing Date
- 2023-09-11
- Publication Date
- 2026-05-05
AI Technical Summary
In existing technologies, wheat bran fiber has limited adsorption sites and insufficient adsorption capacity for dye wastewater, making it difficult to effectively treat dye wastewater. Furthermore, adsorption materials such as activated carbon are costly and difficult to regenerate.
A combination of ultra-high pressure treatment and chemical modification was used to remove water-soluble components and soluble dietary fiber through ultra-high pressure treatment. Subsequently, the adsorption sites of wheat bran were increased by synergistic treatment with sodium hydroxide, epichlorohydrin and dimethylamine, thereby achieving amination modification and improving adsorption capacity.
It significantly improves the adsorption capacity of wheat bran fiber, enabling it to exhibit excellent adsorption performance in dye wastewater treatment, while being low in cost and renewable.
Smart Images
Figure CN117230548B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of comprehensive utilization of agricultural by-products, specifically relating to a modified wheat bran fiber and its preparation and application. Background Technology
[0002] Wheat bran is the outer layer of wheat grains, obtained during wheat milling after the grains are ground. It comprises approximately one-quarter of the original wheat grain weight and is an important byproduct of wheat processing. While wheat bran is abundant, it is currently mainly used in animal feed and fermentation, with its processing and utilization being underutilized. Its application value needs further exploration. Therefore, strengthening the development and utilization of wheat bran can effectively reduce resource waste and increase the added value of the wheat industry. Summary of the Invention
[0003] In view of this, the present invention aims to provide a modified wheat bran fiber, a method for preparing the wheat bran fiber, and also relates to the application of the wheat bran fiber in adsorption.
[0004] The technical solution adopted in this invention is as follows:
[0005] A method for preparing modified wheat bran fiber, characterized by comprising the following steps:
[0006] 1) Wheat bran is crushed and sieved to obtain wheat bran powder;
[0007] 2) Add water to wheat bran powder and process it under ultra-high pressure to obtain a wheat bran powder mixture;
[0008] 3) Centrifuge the wheat bran powder mixture obtained in the previous step, discard the supernatant, add water to the collected precipitate (the amount of water is 2-3 times the mass of the precipitate), stir and let stand (1-1.5h), centrifuge again, and collect the precipitate;
[0009] 4) Add water and amylase to the precipitate obtained in the previous step, adjust the pH to 3.5-4.0, keep warm and shake to react, then add saccharifying enzyme, keep warm and shake to react, centrifuge to separate, and collect the precipitate;
[0010] 5) Add water and protease to the precipitate obtained in the previous step, adjust the pH to 7.0-7.5, keep warm and shake the reaction, centrifuge to separate, and collect the precipitate, which is the insoluble fiber of wheat bran;
[0011] 6) Add NaOH solution to the insoluble wheat bran fiber obtained in the previous step, stir and let stand (1-1.5h), then centrifuge and collect the precipitate;
[0012] 7) Add epichlorohydrin solution to the precipitate obtained in the previous step, stir and filter. Wash the filter residue with water and acetone in turn.
[0013] 8) Add dimethylamine solution to the filter residue obtained in the previous step, stir to react, filter, and wash the filter residue with water and acetone in turn.
[0014] 9) Dry the filter residue obtained in the previous step to obtain modified wheat bran fiber.
[0015] In step 2), the mass of water is 2-3 times the mass of wheat bran powder, and the ultra-high pressure treatment conditions are: room temperature, 200-400 MPa, 10-15 minutes.
[0016] In step 4), the amount of water used is 1-1.5 times the mass of the precipitate, the amount of amylase used is 100-150U / 100g of the mixture, and the amount of saccharifying enzyme used is 60-100U / 100g of the mixture.
[0017] In step 5), the amount of water used is 1-1.5 times the mass of the precipitate, and the amount of protease used is 150-200U / 100g of the mixture.
[0018] In step 6), the concentration of the NaOH solution is 20-30%, and the amount added is 10-15 times the mass of the insoluble fiber in wheat bran.
[0019] In step 7), the concentration of epichlorohydrin solution is 99.0-99.5%, the amount added is 4-8 times the mass of the precipitate, the stirring time is 4-8 hours, and the amount of water and acetone is 2-3 times the mass of the filter residue.
[0020] In step 8), the concentration of dimethylamine solution is 30%-35%, and the amount added is 4-8 times the mass of the filter residue. The reaction is carried out at 60-80℃ for 3-5 hours, and the amount of water and acetone is 2-3 times the mass of the filter residue. In step 9), the drying conditions are: 80-100℃ for 10-14 hours.
[0021] The centrifugation conditions are: 2000-3000 rpm for 10-15 minutes; and the reaction is carried out at 50-55℃ for 2-3 hours during the incubation and shaking reaction.
[0022] Modified wheat bran fiber obtained by the above method.
[0023] The modified wheat bran fiber is used as a dye adsorbent.
[0024] The inventor has been researching the comprehensive utilization of wheat bran for many years, exploring the application of wheat bran fiber. The inventor also discovered that dye wastewater is a common form of water pollution. The main components of dye wastewater include aromatic rings, amino groups, and azo groups, making it complex and harmful to the environment. Treating dye wastewater is a challenging problem. Currently, adsorption is the most mature method for treating dye wastewater, with commonly used adsorption materials such as activated carbon. However, activated carbon is expensive and difficult to regenerate. Using agricultural byproducts to treat dye wastewater would significantly reduce costs. Raw wheat bran fiber was a material the inventor had previously tried, but found that its limited adsorption sites restricted its adsorption capacity, making it ineffective for adsorbing dye wastewater.
[0025] Compared with the prior art, the beneficial technical effects of the present invention are:
[0026] In this invention, ultra-high pressure treatment is employed to remove water-soluble components and soluble dietary fiber from wheat bran under ultra-high pressure conditions, which facilitates the extraction of insoluble dietary fiber. Ultra-high pressure treatment of wheat bran lays the foundation for subsequent chemical modification, making it easier to attach amylation groups and maximizing the adsorption effect. Based on ultra-high pressure treatment, the wheat bran is further chemically modified through the synergistic treatment of sodium hydroxide, epichlorohydrin, and dimethylamine, which significantly enhances the adsorption capacity of the wheat bran. The physical and chemical modifications achieve a synergistic effect. Attached Figure Description
[0027] Figure 1 The image shows scanning electron microscope (SEM) images of wheat bran before and after modification in Example 1.
[0028] Figure 2 The image shows the infrared spectra of wheat bran before and after modification in Example 1. Detailed Implementation
[0029] The following examples illustrate specific implementations of the present invention. However, these examples are merely for illustrative purposes and do not limit the scope of the invention in any way.
[0030] Example 1:
[0031] A method for preparing modified wheat bran fiber includes the following steps:
[0032] 1) Crush the dried wheat bran, pass it through a 40-mesh sieve, and collect the sieve-passing material as wheat bran powder;
[0033] 2) Then add water twice the weight of wheat bran powder to the wheat bran powder, put it in a plastic bag, and perform ultra-high pressure treatment at room temperature, 200 MPa, for 15 minutes to obtain wheat bran mixture.
[0034] 3) Centrifuge the wheat bran mixture at 2000 rpm for 15 minutes, discard the supernatant, add twice the mass of water to the precipitate, stir and let stand for 1 hour, then centrifuge again (2000 rpm for 15 minutes), discard the supernatant and collect the precipitate.
[0035] 4) Add water equal to the mass of the precipitate obtained in the previous step, then add amylase at a concentration of 100 U / 100g of the mixture. Adjust the pH of the solution to 3.5, incubate at 50°C with shaking for 3 hours, then add saccharifying enzyme at a concentration of 60 U / 100g of the mixture. Incubate at 55°C with shaking for 2 hours, then centrifuge (2000 rpm for 15 minutes), discard the supernatant, and collect the precipitate.
[0036] 5) Add water of the same mass as the precipitate to the precipitate from the previous step, add protease at a rate of 200 U / 100g of the mixture, adjust the pH of the solution to 7.0, incubate at 50℃ with shaking for 3 hours, centrifuge (2000 rpm for 15 minutes), discard the supernatant, and collect the precipitate, which is the insoluble fiber of wheat bran.
[0037] 6) Add a 20% NaOH solution to the insoluble wheat bran fiber obtained in the previous step. The amount added should be 15 times the mass of the insoluble wheat bran fiber. After stirring evenly, let it stand for 1.5 hours, then centrifuge (2000 rpm for 15 minutes). Discard the supernatant and collect the precipitate.
[0038] 7) Add a 99% epichlorohydrin solution to the precipitate, the amount of which is 4 times the mass of the precipitate. Stir magnetically at room temperature for 4 hours, filter, take the filter residue, and wash the filter residue with water and acetone in turn, the amount of water and acetone used for washing being 2 times the mass of the filter residue.
[0039] 8) Add a 30% dimethylamine solution to the filter residue obtained in the previous step. The amount added is 8 times the mass of the filter residue. Keep it at 60℃ and react for 5 hours. Filter and take the filter residue. Wash the filter residue with water and acetone in sequence. The amount of water and acetone used for washing is 3 times the mass of the filter residue, respectively.
[0040] 9) Dry the filter residue obtained in the previous step with hot air at 100℃ for 10 hours to obtain modified wheat bran fiber.
[0041] The scanning electron microscope images of wheat bran fiber before and after modification obtained in this embodiment are as follows: Figure 1 As shown, by Figure 1 It can be seen that the wheat bran before modification contains insoluble dietary fiber, while the wheat bran modified by the method of this invention no longer contains insoluble dietary fiber, and the pores and wrinkles are greatly increased, which means that the adsorption capacity has been significantly improved.
[0042] Depend on Figure 2 It can be seen that the modified wheat bran has characteristic absorption peaks of CN and NH groups, indicating that the chemical modification of insoluble dietary fiber in wheat bran was successful and achieved amination modification.
[0043] Example 2
[0044] A method for preparing modified wheat bran fiber includes the following steps:
[0045] 1) Crush the dried wheat bran, pass it through a 60-mesh sieve, and collect the sieve-passing material as wheat bran powder;
[0046] 2) Then add water at a ratio of 3 times the weight of wheat bran powder to the wheat bran powder, put it in a plastic bag, and perform ultra-high pressure treatment at room temperature, 400 MPa, for 10 minutes to obtain wheat bran mixture.
[0047] 3) Centrifuge the wheat bran mixture obtained in the previous step at 3000 rpm for 10 minutes, discard the supernatant, add water three times the mass of the precipitate to the precipitate, stir and let stand for 1.5 hours, then centrifuge again (3000 rpm for 10 minutes), discard the supernatant and collect the precipitate.
[0048] 4) Add 1.5 times the mass of water to the precipitate obtained in the previous step, then add amylase at a concentration of 150 U / 100g. Adjust the pH of the solution to 4.0, incubate at 55℃ with shaking for 2 hours, then add saccharifying enzyme at a concentration of 100 U / 100g. Incubate at 50℃ with shaking for 3 hours, centrifuge (3000 rpm for 10 minutes), discard the supernatant, and collect the precipitate.
[0049] 5) Add 1.5 times the mass of water to the precipitate, add protease at a concentration of 150 U / 100g of the mixture, adjust the pH of the solution to 7.5, incubate at 55℃ with shaking for 2 hours, centrifuge (3000 rpm for 10 minutes), discard the supernatant, and collect the precipitate, which is the insoluble fiber of wheat bran.
[0050] 6) Add a 30% NaOH solution to the insoluble wheat bran fiber obtained in the previous step. The amount added should be 10 times the mass of the insoluble wheat bran fiber. After stirring evenly, let it stand for 1 hour, then centrifuge (3000 rpm for 10 minutes). Discard the supernatant and collect the precipitate.
[0051] 7) Add a 99.5% epichlorohydrin solution to the precipitate obtained in the previous step. The amount added is 8 times the mass of the precipitate. Stir magnetically at room temperature for 8 hours, filter, take the filter residue, and wash the filter residue with water and acetone in turn. The amount of water and acetone used for washing is 3 times the mass of the filter residue, respectively.
[0052] 8) Add a 35% dimethylamine solution to the filter residue obtained in the previous step. The amount added is 4 times the mass of the precipitate. Keep the temperature at 70℃ and react for 3 hours. Filter and take the filter residue. Wash the filter residue with water and acetone in sequence. The amount of water and acetone used for washing is 2 times the mass of the filter residue.
[0053] 9) Dry the filter residue with hot air at 80℃ for 14 hours to obtain modified wheat bran fiber.
[0054] Example 3
[0055] A method for preparing modified wheat bran fiber includes the following steps:
[0056] 1) Crush the dried wheat bran, pass it through a 60-mesh sieve, and collect the sieve-passing material as wheat bran powder;
[0057] 2) Then, add 2.5 times the weight of water to the wheat bran powder, put it in a plastic bag, and perform ultra-high pressure treatment at room temperature, 300 MPa, for 13 minutes to obtain a wheat bran mixture.
[0058] 3) Centrifuge the wheat bran mixture at 2500 rpm for 12 minutes, discard the supernatant, add 2.5 times the mass of water to the precipitate, stir and let stand for 1.3 hours, then centrifuge again (2500 rpm for 12 minutes), discard the supernatant and collect the precipitate.
[0059] 4) Add 1.3 times the mass of water to the precipitate obtained in the previous step, then add amylase at a concentration of 120 U / 100g of the mixture. Adjust the pH of the solution to 3.8, incubate at 53°C with shaking for 2.5 hours, then add saccharifying enzyme at a concentration of 80 U / 100g of the mixture. Incubate at 53°C with shaking for 2.5 hours, centrifuge (2500 rpm for 12 minutes), discard the supernatant, and collect the precipitate.
[0060] 5) Add 1.3 times the mass of water to the precipitate obtained in the previous step, add protease, the amount of protease is 180U / 100g of mixture, adjust the pH of the solution to 7.2, keep it at 53℃ and shake for 2.5h, centrifuge (2500 rpm, centrifuge for 12 minutes), discard the supernatant, and collect the precipitate, which is the insoluble fiber of wheat bran.
[0061] 6) Add a 25% NaOH solution to the insoluble wheat bran fiber obtained in the previous step. The amount added should be 13 times the mass of the insoluble wheat bran fiber. After stirring evenly, let it stand for 1.2 hours, then centrifuge (2500 rpm for 12 minutes). Discard the supernatant and collect the precipitate.
[0062] 7) Add a 99.3% epichlorohydrin solution to the precipitate from the previous step. The amount added is 6 times the mass of the precipitate. Stir magnetically at room temperature for 6 hours, filter, take the filter residue, and wash the filter residue with water and acetone in sequence. The amount of water and acetone used for washing is 2.5 times the mass of the filter residue, respectively.
[0063] 8) Add a 33% dimethylamine solution to the filter residue obtained in the previous step. The amount added is 6 times the mass of the filter residue. Keep the temperature at 65℃ and react for 2.5 hours. Filter and take the filter residue. Wash the filter residue with water and acetone in sequence. The amount of water and acetone used for washing is 2.5 times the mass of the filter residue, respectively.
[0064] 9) Dry the filter residue obtained in the previous step with hot air at 90℃ for 12 hours to obtain modified wheat bran fiber.
[0065] Example 4
[0066] A method for preparing modified wheat bran fiber includes the following steps:
[0067] 1) Crush the dried wheat bran, pass it through a 40-mesh sieve, and collect the sieve-passing material as wheat bran powder;
[0068] 2) Then add water twice the weight of wheat bran powder to the wheat bran powder, put it in a plastic bag, and perform ultra-high pressure treatment at room temperature, 200 MPa, for 15 minutes to obtain wheat bran mixture.
[0069] 3) Centrifuge the wheat bran mixture at 2000 rpm for 15 minutes, discard the supernatant, add twice the mass of water to the precipitate, stir and let stand for 1 hour, then centrifuge again (2000 rpm for 15 minutes), discard the supernatant and collect the precipitate.
[0070] 4) Add water equal to the mass of the precipitate obtained in the previous step, then add amylase at a concentration of 100 U / 100g of the mixture. Adjust the pH of the solution to 3.5, incubate at 50°C with shaking for 3 hours, then add saccharifying enzyme at a concentration of 60 U / 100g of the mixture. Incubate at 55°C with shaking for 2 hours, then centrifuge (2000 rpm for 15 minutes), discard the supernatant, and collect the precipitate.
[0071] 5) Add water of the same mass as the precipitate to the precipitate from the previous step, add protease at a rate of 200 U / 100g of the mixture, adjust the pH of the solution to 7.0, incubate at 50℃ with shaking for 3 hours, centrifuge (2000 rpm for 15 minutes), discard the supernatant, and collect the precipitate, which is the insoluble fiber of wheat bran.
[0072] 6) Dry the insoluble wheat bran fiber obtained in the previous step with hot air at 100℃ for 10 hours to obtain wheat bran fiber.
[0073] Example 5
[0074] A method for preparing modified wheat bran fiber includes the following steps:
[0075] 1) Crush the dried wheat bran, pass it through a 40-mesh sieve, and collect the sieve-passing material as wheat bran powder;
[0076] 2) Then add water twice the weight of wheat bran powder to the wheat bran powder and stir to obtain a wheat bran mixture. Centrifuge the wheat bran mixture at 2000 rpm for 15 minutes, discard the supernatant, add water twice the weight of the precipitate to the precipitate again, stir and let stand for 1 hour, then centrifuge again (2000 rpm for 15 minutes), discard the supernatant and collect the precipitate.
[0077] 3) Add water equal to the mass of the precipitate obtained in the previous step, then add amylase at a concentration of 100 U / 100g of the mixture. Adjust the pH of the solution to 3.5, incubate at 50°C with shaking for 3 hours, then add saccharifying enzyme at a concentration of 60 U / 100g of the mixture. Incubate at 55°C with shaking for 2 hours, then centrifuge (2000 rpm for 15 minutes), discard the supernatant, and collect the precipitate.
[0078] 4) Add water of the same mass as the precipitate to the precipitate from the previous step, add protease at a rate of 200 U / 100g of the mixture, adjust the pH of the solution to 7.0, incubate at 50℃ with shaking for 3 hours, centrifuge (2000 rpm for 15 minutes), discard the supernatant, and collect the precipitate, which is the insoluble fiber of wheat bran.
[0079] 5) Add a 20% NaOH solution to the insoluble wheat bran fiber obtained in the previous step. The amount added should be 15 times the mass of the insoluble wheat bran fiber. After stirring evenly, let it stand for 1.5 hours, then centrifuge (2000 rpm for 15 minutes). Discard the supernatant and collect the precipitate.
[0080] 6) Add a 99% epichlorohydrin solution to the precipitate, the amount of which is 4 times the mass of the precipitate. Stir magnetically at room temperature for 4 hours, filter, take the filter residue, and wash the filter residue with water and acetone in turn, the amount of water and acetone used for washing being 2 times the mass of the filter residue.
[0081] 7) Add a 30% dimethylamine solution to the filter residue obtained in the previous step. The amount added is 8 times the mass of the filter residue. Keep it at 60℃ and react for 5 hours. Filter and take the filter residue. Wash the filter residue with water and acetone in sequence. The amount of water and acetone used for washing is 3 times the mass of the filter residue.
[0082] 8) Dry the filter residue obtained in the previous step with hot air at 100℃ for 10 hours to obtain modified wheat bran fiber.
[0083] Adsorption capacity determination experiments were conducted on the modified wheat bran fibers obtained in Examples 1-5:
[0084] Prepare 100 mL of Congo red (azo dye) solution at a concentration of 100 mg / L, and add 0.1 g of modified wheat bran fiber from Examples 1-5 respectively. After magnetic stirring for 120 min, take an appropriate amount of solution, centrifuge, and measure the absorbance of the supernatant. Calculate the dye residue and adsorption capacity. The results are shown in Table 1 below:
[0085]
[0086] Q – Adsorption capacity, in mg / g;
[0087] C0—Initial solution concentration, in mg / L;
[0088] Ct — solution concentration at time t, in mg / L;
[0089] V – Solution volume, in L;
[0090] M – Adsorbent mass, in grams.
[0091] Table 1 Adsorption Capacity Table
[0092] Adsorption capacity (mg / g) Unmodified insoluble dietary fiber from raw wheat bran <![CDATA[19±5 a ]]> Example 1 <![CDATA[126±7 d ]]> Example 2 <![CDATA[128±6 d ]]> Example 3 <![CDATA[128±7 d ]]> Example 4 <![CDATA[30±4 b ]]> Example 5 <![CDATA[82±6 c ]]>
[0093] Note: Different superscript letters indicate significant differences, P<0.05.
[0094] As shown in Table 1, the adsorption capacity of insoluble dietary fiber from unmodified raw wheat bran was 19 mg / g. After physical modification by ultra-high pressure treatment, the adsorption capacity of wheat bran increased to 30 mg / g, an increase of approximately 30%. With only chemical modification, the adsorption capacity of wheat bran reached 82 mg / g, approximately four times that of the unmodified bran. When physical and chemical modification were combined, the adsorption capacity increased to approximately six times that of the unmodified bran, indicating that physical and chemical modification not only have a simple additive effect but also a synergistic effect.
[0095] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Any other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention, as long as they do not depart from the spirit and scope of the technical solutions of the present invention, should be covered within the scope of the claims of the present invention.
Claims
1. A method for preparing modified wheat bran fiber, characterized in that... Includes the following steps: 1) Wheat bran is crushed and sieved to obtain wheat bran powder; 2) Water is added to wheat bran powder, and the mixture is subjected to ultra-high pressure treatment to obtain a wheat bran powder mixture; 3) Centrifuge the wheat bran powder mixture obtained in the previous step, discard the supernatant, add water to the collected precipitate, stir and let stand, centrifuge again, and collect the precipitate; 4) Add water and amylase to the precipitate obtained in the previous step, adjust the pH to 3.5-4.0, keep warm and shake to react, then add saccharifying enzyme, keep warm and shake to react, centrifuge to separate, and collect the precipitate; 5) Add water and protease to the precipitate obtained in the previous step, adjust the pH to 7.0-7.5, keep warm and shake the reaction, centrifuge to separate, and collect the precipitate, which is the insoluble fiber of wheat bran; 6) Add NaOH solution to the insoluble wheat bran fiber obtained in the previous step, stir, let stand, centrifuge, and collect the precipitate; 7) Add epichlorohydrin solution to the precipitate obtained in the previous step, stir and filter. Wash the filter residue with water and acetone in turn. 8) Add dimethylamine solution to the filter residue obtained in the previous step, stir to react, filter, and wash the filter residue with water and acetone in turn. 9) Dry the filter residue obtained in the previous step to obtain modified wheat bran fiber.
2. The preparation method according to claim 1, characterized in that: In step 2), the mass of water is 2-3 times the mass of wheat bran powder, and the ultra-high pressure treatment conditions are: room temperature, 200-400 MPa, 10-15 minutes.
3. The preparation method according to claim 1, characterized in that: In step 6), the concentration of the NaOH solution is 20-30%, and the amount added is 10-15 times the mass of the insoluble fiber in wheat bran.
4. The preparation method according to claim 1, characterized in that: In step 7), the concentration of epichlorohydrin solution is 99.0-99.5%, the amount added is 4-8 times the mass of the precipitate, the stirring time is 4-8 hours, and the amount of water and acetone is 2-3 times the mass of the filter residue.
5. The preparation method according to claim 1, characterized in that: In step 8), the concentration of dimethylamine solution is 30%-35%, and the amount added is 4-8 times the mass of the filter residue. The reaction is carried out at 60-80℃ for 3-5 hours, and the amount of water and acetone is 2-3 times the mass of the filter residue. In step 9), the drying conditions are: 80-100℃ for 10-14 hours.
6. The preparation method according to claim 1, characterized in that: The centrifugal separation conditions are: 2000-3000 rpm, centrifugation for 10-15 minutes; During the heat preservation and shaking reaction, the reaction should be carried out at 50-55℃ for 2-3 hours.
7. Modified wheat bran fiber prepared by the method of claim 1.
8. The application of the modified wheat bran fiber according to claim 7 as a dye adsorbent.