A method for extracting biomass green pigment from silkworm excrement and application thereof in fabric dyeing

Abstract

The application discloses a method for extracting biomass green pigment from silkworm sand and application of the biomass green pigment in fabric dyeing. The method comprises the following steps: taking silkworm sand as raw material, and adopting anhydrous extraction method combined with nano solid acid catalysis and low-temperature ultrasonic energy. In the extraction method, the concentration of the nano solid acid is 1-3 g / L, the solid-liquid ratio is 1:4-12, the ultrasonic power is 220-400 W, the ultrasonic temperature is 40-65 DEG C, and the ultrasonic time is 30-150 min. The obtained chlorophyll dye has good dyeing affinity to silk fabric, the dyeing pH value is 3-8, the dyeing temperature is 60-80 DEG C, the dyeing time is 40-60 min, and the dyed fabric has soft color, excellent color fastness and antibacterial and ultraviolet resistance. The method utilizes the synergistic catalysis of Lewis acid and Bronsted acid of the nano solid acid and the ultrasonic energy to promote the swelling and crushing of the biomass cell wall, the catalyst is easy to separate and recycle, and the low-temperature, high-efficiency and green extraction process is realized, which provides a feasible path for resource utilization of silkworm sand waste and development of natural functional dye.

Description

Technical Field

[0001] This invention relates to the field of biomass extraction and recycling technology, and more specifically to a method for extracting green pigment from silkworm excrement and its application in fabric dyeing. Background Technology

[0002] With the global demands for carbon emission reduction and sustainable development, natural bio-dyes have gained widespread attention in multifunctional textile dyeing due to their non-toxic and environmentally friendly properties. Silkworm excrement is one of the most important byproducts of sericulture. Statistics show that China produces 5 million tons of silkworm excrement annually; however, the vast majority is discarded or used only as feed or fertilizer, resulting in a single utilization method and serious resource waste.

[0003] Silkworm excrement is rich in chlorophyll and its derivatives, such as flavonoids, carotenoids, and alkaloids, which are various bioactive substances. The content of chlorophyll derivatives, which are green dyes, accounts for 0.5-1% of the dry matter content of silkworm excrement. Developing natural bio-pigments can not only make full use of natural resources and reduce production costs, but also reduce environmental pollution. Traditional chlorophyll extraction methods mainly have the following problems: (1) large solvent consumption, which poses an environmental pollution risk; (2) low extraction efficiency and high energy consumption; (3) high temperature conditions during the extraction process can easily destroy the structure of dye molecules, resulting in unstable dye molecules in the extract; (4) catalysts or solvents are difficult to separate and recover.

[0004] In the prior art, CN102093369B discloses a method for extracting chlorophyll from silkworm excrement and preparing sodium ferrochlorophyllin. This method uses an ultra-micro vibration mill in conjunction with medium-concentration ethanol for extraction at 45-55℃. This method improves extraction efficiency through physical pulverization, but simple physical pulverization still has limited extraction efficiency for chlorophyll that is tightly bound to lignin and cellulose, and prolonged mechanical pulverization may generate localized high temperatures.

[0005] Therefore, developing a more efficient, mild, and green method for extracting chlorophyll from silkworm excrement is of great significance for the resource utilization of silkworm excrement waste and the development of natural functional dyes. Summary of the Invention

[0006] This invention aims to solve the technical problems existing in the extraction of chlorophyll from silkworm excrement, such as low extraction efficiency, high energy consumption, high temperature that easily damages the dye molecular structure, difficulty in separating solvent / catalyst, and environmental pollution. It provides an efficient, mild, and green method for extracting green pigments from biomass from silkworm excrement.

[0007] The technical solution adopted by the present invention to solve the technical problem is: a method for extracting green pigment from silkworm excrement. The extraction method includes the following steps: mixing the crushed silkworm excrement with a solvent, and extracting chlorophyll from the silkworm excrement by low-temperature ultrasonic anhydrous extraction under the catalysis of nano solid acid, to obtain an extract containing chlorophyll; and separating the solid and liquid components of the extract, removing the solvent, and purifying it to obtain chlorophyll.

[0008] Furthermore, in the extraction method, the concentration of the nano-solid acid is 1~3g / L; the material-liquid ratio is 1:4~12; the ultrasonic power is 220~400W; the ultrasonic temperature is 40~65℃; and the ultrasonic time is 30~150 min.

[0009] Furthermore, the nano-solid acid is a nano-solid superacid possessing both Lewis acid and Brønsted acid sites; the nano-solid acid is SO4. 2- / TiO2 nano-solid acid; the nano-solid acid is synthesized by the sol-gel method.

[0010] Further, the solvent is any one of methanol, ethanol, propanol, acetone, butanone, and acetonitrile; after extracting the pulverized silkworm excrement and cooling it to room temperature, it is vacuum filtered to obtain a chlorophyll extract; then the ethanol is removed by distillation to obtain crude chlorophyll, and finally chlorophyll and its derivatives are obtained by recrystallization from ethanol.

[0011] This invention utilizes the synergistic catalytic effect of Lewis acids and Brønsted acids in nano-solid acids to efficiently swell bio-cellulose and lignin in silkworm excrement. Simultaneously, it combines this with the physical disruption of biomass cell walls using ultrasonic energy, achieving a synergistic effect of chemical swelling and physical disruption, resulting in the efficient dissolution of intracellular biomass molecules (chlorophyll). Because the extraction process is carried out at low temperatures (40-65℃), the molecular structure of the extract is completely preserved. After extraction, the nano-solid acid catalyst is easily separated and recovered from the system, and the ethanol solvent can be recycled through distillation. The entire process is green, anhydrous, and pollution-free.

[0012] The present invention also discloses a chlorophyll bio-dye obtained by the extraction method described above.

[0013] The present invention also discloses the application of the above-mentioned chlorophyll bio-dyes in textile dyeing.

[0014] Furthermore, the application of the chlorophyll bio-dye in textile dyeing, wherein the textile is a silk fabric; the dyeing conditions for the silk fabric are: pH value 3~8, dyeing temperature 60~80 ℃, liquor ratio 1:10, and dyeing time 40~60 min.

[0015] This invention also discloses a dyed fabric, obtained by dyeing textiles with the aforementioned chlorophyll bio-dye; the fabric is a silk fabric; after treatment with the chlorophyll bio-dye, a multifunctional silk textile with antibacterial and UV-resistant properties is obtained. Chlorophyll and its derivatives are photosensitizers; under light, chlorophyll can generate reactive oxygen species, thereby killing bacteria. Pigments in plant extracts (such as flavonoids, chlorophyll, etc.) can usually effectively absorb ultraviolet rays, and biomass chlorophyll can endow fabrics with UV-resistant properties.

[0016] The beneficial effects of this invention are as follows: Compared with the prior art, this invention has the following advantages: 1) High extraction efficiency: Through the synergistic effect of nano solid acid catalysis and ultrasonic energy, the extraction rate of chlorophyll is significantly improved, reaching up to 6.38 mg / g silkworm excrement.

[0017] 2) Low extraction temperature and low energy consumption: The extraction temperature only needs to be 40~65℃, which avoids the damage of high temperature to the chlorophyll molecular structure and maintains the biological activity of dye molecules; low temperature extraction and efficient extraction process greatly reduce energy consumption.

[0018] 3) Green and environmentally friendly, with high product purity: The entire process is water-free, the ethanol solvent is recyclable, and the nano-solid acid catalyst is easy to separate and recover, resulting in no environmental pollution. The extracted chlorophyll has a complete structure, high purity, and excellent staining properties.

[0019] 4) Excellent dyeing performance: The extracted chlorophyll bio-dye has good dyeing affinity for silk fabrics, and the dyed fabrics have soft color, excellent color fastness, and antibacterial and anti-ultraviolet properties.

[0020] 5) Resource recycling: It realizes the high-value utilization of silkworm excrement waste and builds an internal industrial cycle chain of "silkworm excrement-chlorophyll-silk", which is in line with the development concept of green textiles. Attached Figure Description

[0021] Figure 1 This is the ultraviolet-visible spectrum of the chlorophyll dye in this invention.

[0022] Figure 2 This is the Fourier transform infrared spectrum of the chlorophyll dye in this invention.

[0023] Figure 3 This is a photograph of the appearance of a dyed fabric sample obtained under the dyeing condition of pH 3 according to the present invention.

[0024] Figure 4 This is a photograph of the appearance of a dyed fabric sample obtained under the dyeing condition of pH 6 according to the present invention.

[0025] Figure 5This is a photograph of the appearance of a dyed fabric sample obtained under the dyeing condition of pH 8 according to the present invention. Detailed Implementation

[0026] The present invention will be further illustrated below with specific embodiments. However, these examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0027] This invention utilizes silkworm excrement, a waste product of silkworms, as raw material. Through a low-temperature ultrasonic energy anhydrous extraction method catalyzed by nano-solid acid, a green low-temperature extraction technology for the bio-dye chlorophyll has been invented. This method successfully and efficiently extracts natural chlorophyll from silkworm excrement. Compared with traditional solvent extraction methods, this method involves lower temperatures, higher efficiency, and lower energy consumption. The molecular structure of the extract is not damaged, the catalyst is easily separated, and the process is green, anhydrous, and pollution-free. Furthermore, it has been applied to the ecological dyeing of silk fabrics, resulting in multifunctional silk textiles with antibacterial and UV-resistant properties. This not only endows silk with a natural, soft color and unique functionality but also constructs an internal industrial cycle chain of "silkworm excrement-chlorophyll-silk," aligning with the development concept of green textiles. The following are several specific implementation examples to illustrate this invention.

[0028] Example 1 Preparation of nano-solid acids: SO4 was synthesized using the sol-gel method. 2- / TiO2 nano-solid acid. First, 10 mL of tetrabutyl titanate (TBOT) was added to a mixture of 50 mL of ethanol and 10 mL of glacial acetic acid (solution A). Next, 6.25 mL of water was mixed into 25 mL of ethanol (solution B). Then, solution B was added dropwise to solution A under vigorous stirring. The mixture was stirred at ambient temperature for 3 hours, and then aged for 24 hours to form a homogeneous gel. Afterward, the gel was dried by rotary evaporation and then immersed in 50 mL of 1 mol / L H2SO4 solution. TiO2 powder was stirred in H2SO4 solution for 8 hours and aged for 24 hours. Then, it was collected by filtration and dried. Finally, it was calcined at 500°C for 3 hours. After grinding and dispersion, Lewis acid and Brønsted acid nano-solid acid were obtained, with the following chemical structures:

[0029] By utilizing the synergistic catalysis of Lewis acid and Brønsted acid in nano-solid acid, a highly efficient swelling effect on bio-cellulose and lignin is achieved. This, combined with ultrasonic energy, swells the cells and cell walls in biomass, resulting in a highly efficient biomass molecule extraction effect and enabling efficient dissolution of bio-dyes in the system.

[0030] The silkworm excrement sample was pulverized and passed through a 60-mesh sieve. A certain amount of silkworm excrement was accurately weighed and placed in a three-necked flask, and a certain volume of ethanol was added. Chlorophyll was extracted from the silkworm excrement using a low-temperature ultrasonic energy anhydrous extraction method catalyzed by nano-solid acid (2 g / L), a solid-liquid ratio of 1:4, an ultrasonic power of 220 W, a temperature of 40 ℃, and a time of 50 min. After extraction, the mixture was cooled to room temperature and vacuum filtered to obtain the chlorophyll extract. Ethanol was removed by distillation to obtain chlorophyll, which was then recrystallized from ethanol. The chlorophyll extraction rate reached 5.63 mg / g (5.63 mg of chlorophyll dye was extracted per gram of silkworm excrement). The structure of the compound was characterized using an FTS-25PC Fourier transform infrared spectroscopy (FTIR) instrument, and the absorption spectrum was measured using an ultraviolet-visible absorption spectrometer (UV-Vis). The infrared and UV-Vis spectra are shown below. Figure 1 and Figure 2 .

[0031] Example 2 The preparation of nano-solid acids is the same as in Example 1.

[0032] The silkworm excrement sample was pulverized and passed through a 60-mesh sieve. A certain amount of silkworm excrement was accurately weighed and placed in a three-necked flask, and a certain volume of ethanol was added. A low-temperature ultrasonic energy anhydrous extraction method catalyzed by nano-solid acid was used. The nano-solid acid concentration was 2 g / L, the material-to-liquid ratio was 1:8, the ultrasonic power was 360 W, the temperature was 50 ℃, and the time was 100 min to extract chlorophyll from the silkworm excrement. After extraction, the sample was cooled to room temperature and vacuum filtered to obtain the chlorophyll extract. The ethanol was removed by distillation to obtain chlorophyll, which was then recrystallized with ethanol. The chlorophyll extraction rate reached 5.97 mg / g (5.97 mg of chlorophyll dye was extracted per gram of silkworm excrement).

[0033] Example 3 The preparation of nano-solid acids is the same as in Example 1.

[0034] The silkworm excrement sample was pulverized and passed through a 60-mesh sieve. A certain amount of silkworm excrement was accurately weighed and placed in a three-necked flask, and a certain volume of ethanol was added. Chlorophyll was extracted from the silkworm excrement using a low-temperature ultrasonic energy anhydrous extraction method catalyzed by nano-solid acid (3 g / L), a solid-liquid ratio of 1:12, an ultrasonic power of 400 W, a temperature of 30 ℃, and a time of 150 min. After extraction, the mixture was cooled to room temperature and vacuum filtered to obtain the chlorophyll extract. The ethanol was removed by distillation to obtain chlorophyll, which was then recrystallized from ethanol. The chlorophyll extraction rate reached 5.51 mg / g (5.51 mg of chlorophyll dye was extracted per gram of silkworm excrement).

[0035] Example 4 The preparation of nano-solid acids is the same as in Example 1.

[0036] The silkworm excrement sample was pulverized and passed through a 60-mesh sieve. A certain amount of silkworm excrement was accurately weighed and placed in a three-necked flask, and a certain volume of ethanol was added. Chlorophyll was extracted from the silkworm excrement using a low-temperature ultrasonic energy anhydrous extraction method catalyzed by nano-solid acid (1 g / L), a solid-liquid ratio of 1:6, an ultrasonic power of 280 W, a temperature of 60 ℃, and a time of 60 min. After extraction, the mixture was cooled to room temperature and vacuum filtered to obtain the chlorophyll extract. The ethanol was removed by distillation to obtain chlorophyll, which was then recrystallized from ethanol. The chlorophyll extraction rate reached 6.38 mg / g (6.38 mg of chlorophyll dye was extracted per gram of silkworm excrement).

[0037] Comparative Example 1 The silkworm excrement sample was pulverized and passed through a 60-mesh sieve. A certain amount of silkworm excrement was accurately weighed and placed in a three-necked flask, and a certain volume of ethanol was added. The material-to-liquid ratio was 1:4. Chlorophyll was extracted from the silkworm excrement using ultrasonic power of 220 W, temperature of 40 ℃, and time of 50 min. After extraction, the mixture was cooled to room temperature and vacuum filtered to obtain the chlorophyll extract. The ethanol was removed by distillation to obtain the chlorophyll, which was then recrystallized with ethanol. The chlorophyll extraction rate reached 2.36 mg / g, less than 50% of that in Example 1. This demonstrates that nano-solid acids play a significant synergistic role in the extraction of biomass dyes.

[0038] Example 6: Dye Application Accurately cut 1 g of silk fabric, use a dye concentration of 4% (owf), dye at 60 ℃, dye for 60 min, use a liquor ratio of 1:10, adjust the pH of the dye bath to 3, and obtain a green color in the silk fabric. A photograph of the dyed fabric sample is shown below. Figure 3 As shown in Table 1, the fabric was fixed with 0.6 g / L CuSO4, and color fastness tests were conducted on the fabric, including wash fastness, rubbing fastness, and light fastness. The obtained fabric achieved a 99% inhibition rate against Staphylococcus aureus and a UPF of 53 for UV resistance.

[0039] Table 1 Color fastness properties of dyed silk fabrics under pH 3 conditions

[0040] Example 7: Staining Application Accurately cut 1 g of silk fabric, use 4% owf dye, dye at 70 ℃, dye for 50 min, use a liquor ratio of 1:10, adjust the pH of the dye bath to 6, and obtain a green color in the silk fabric. A photograph of the dyed fabric sample is shown below. Figure 4As shown in Table 2, the fabric was fixed with 0.6 g / L CuSO4 for color fastness testing, including wash fastness, rubbing fastness, and light fastness. The obtained fabric achieved a 99% inhibition rate against Staphylococcus aureus and a UPF of 53 for UV resistance.

[0041] Table 2 Color fastness properties of dyed silk fabrics under pH 6 conditions

[0042] Example 8: Staining Application Accurately cut 1 g of silk fabric, use 4% owf dye, dye at 80 ℃, dye for 40 min, use a liquor ratio of 1:10, adjust the pH of the dye bath to 8, and obtain a green color in the silk fabric. A photograph of the dyed fabric sample is shown below. Figure 5 As shown in Table 3, the fabric was fixed with 0.6 g / L CuSO4, and color fastness tests were conducted on the fabric, including wash fastness, rubbing fastness, and light fastness. The obtained fabric achieved a 99% inhibition rate against Staphylococcus aureus and a UPF of 53 for UV resistance.

[0043] Table 3 Color fastness properties of dyed silk fabrics at pH 8

[0044] The above embodiments are only used to illustrate the present invention and are not intended to limit the present invention. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also fall within the scope of the present invention, and the patent protection scope of the present invention should be defined by the claims.

Claims

1. A method for extracting green pigment from silkworm excrement, characterized in that, The extraction method includes the following steps: mixing the crushed silkworm excrement with a solvent, and extracting chlorophyll from the silkworm excrement by low-temperature ultrasonic anhydrous extraction under the catalysis of nano solid acid, to obtain an extract containing chlorophyll; after solid-liquid separation, solvent removal, and purification of the extract, chlorophyll is obtained.

2. The method for extracting green pigment from silkworm excrement as described in claim 1, characterized in that: In the extraction method, the concentration of the nano-solid acid is 1~3g / L; the material-liquid ratio is 1:4~12; the ultrasonic power is 220~400W; the ultrasonic temperature is 40~65℃; and the ultrasonic time is 30~150 min.

3. The method for extracting green pigment from silkworm excrement as described in claim 1, characterized in that: The nano-solid acid is a nano-solid superacid possessing both Lewis acid and Brønsted acid sites; the nano-solid acid is SO4. 2- / TiO2 nano-solid acid; the nano-solid acid is synthesized by the sol-gel method.

4. The method for extracting green pigment from silkworm excrement as described in claim 1, characterized in that: The solvent is any one of methanol, ethanol, propanol, acetone, butanone, and acetonitrile; the pulverized silkworm excrement is extracted and cooled to room temperature, then vacuum filtered to obtain chlorophyll extract; ethanol is then removed by distillation to obtain crude chlorophyll, and finally chlorophyll and its derivatives are obtained by recrystallization from ethanol.

5. Chlorophyll bio-dye prepared by the method according to any one of claims 1-4.

6. The application of the chlorophyll bio-dye as described in claim 5 in textile dyeing.

7. The application as described in claim 6, characterized in that, The textile is a silk fabric; the dyeing conditions for the silk fabric are: pH value 3~8, dyeing temperature 60~80 ℃, liquor ratio 1:10, and dyeing time 40~60 min.

8. A dyed fabric, characterized in that, The fabric is obtained by dyeing it with the chlorophyll bio-dye as described in claim 5; the fabric is a silk fabric; after treatment with the chlorophyll bio-dye, a multifunctional silk textile with antibacterial and anti-ultraviolet properties is obtained.

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