CN106832337B - Dissolving method of collagen-containing waste in leather industry and preparation method of porous membrane material - Google Patents
Dissolving method of collagen-containing waste in leather industry and preparation method of porous membrane material Download PDFInfo
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- CN106832337B CN106832337B CN201710024900.3A CN201710024900A CN106832337B CN 106832337 B CN106832337 B CN 106832337B CN 201710024900 A CN201710024900 A CN 201710024900A CN 106832337 B CN106832337 B CN 106832337B
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
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- C08J3/02—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques
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- C08J3/05—Making solutions, dispersions, lattices or gels by other methods than by solution, emulsion or suspension polymerisation techniques in aqueous media from solid polymers
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- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
- C08J9/28—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum
- C08J9/286—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof by elimination of a liquid phase from a macromolecular composition or article, e.g. drying of coagulum the liquid phase being a solvent for the monomers but not for the resulting macromolecular composition, i.e. macroporous or macroreticular polymers
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- C—CHEMISTRY; METALLURGY
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- C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
- C08J2389/00—Characterised by the use of proteins; Derivatives thereof
- C08J2389/04—Products derived from waste materials, e.g. horn, hoof or hair
- C08J2389/06—Products derived from waste materials, e.g. horn, hoof or hair derived from leather or skin
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Abstract
The dissolving method of collagen-containing waste in tanning industry comprises dissolving the collagen waste in a salt-water system selected from LiBr water solution and CaCl2-one of an ethanol-water solution, a NaSCN-water solution and a LiBr-dimethylsulfoxide-water solution. Also discloses a method for preparing the porous membrane material by using the dissolving method. The invention processes the collagen waste in a dissolving way to construct a novel collagen-based material-porous membrane material which can be used for cell culture, catalysis and other aspects and is expected to realize high-value utilization of collagen biomass materials; the dissolution mode of the collagen waste is low in cost and high in solubility, and the molecular weight of the collagen obtained by dissolution is high; the whole preparation process is simple, the reaction condition is mild, the operability is strong, and the industrial popularization of the method is facilitated.
Description
Technical Field
The invention belongs to the technical field of materials, and particularly relates to a dissolving method of collagen-containing waste in the leather industry and a preparation method of a porous membrane material.
Background
About more than 140 million tons of leather corner wastes are not effectively treated every year in the leather-making industry in China, so that not only is great resource waste caused, but also a factor of environmental pollution is caused. The severe situation of resource and environmental issues requires that the tanning industry must accept the challenges of the "sustainable development" strategy. How to effectively recycle the tanning wastes is a problem which is generally concerned by people outside the industry.
The collagen-containing waste in the prior leather making is mostly used in the fields of low added value such as regenerated leather filling, feed and the like through simple mechanical crushing. At present, as a material rich in natural polymers, the most suitable processing mode of the collagen-containing waste is 'dissolution'. The dissolution of soluble collagen mainly adopts an acid dissolution method and a salt dissolution method. The acid dissolution method is to destroy the intermolecular salt bond and Schiff bond of collagen by using a low concentration of acid, and to cause the collagen fiber to swell until dissolution. The acid used as the solvent is mainly acetic acid, citric acid, formic acid, or the like. However, collagen has limited solubility in dilute acid, and protein molecular chains are degraded to some extent under the action of acidic conditions. The salt dissolution method is to dissolve collagen using high concentration of salts such as sodium chloride, etc., and the concentration and use conditions of these neutral salts are strictly controlled, otherwise the stability of collagen fibers in solution is deteriorated, thereby causing strong molecular degradation. The dissolving method aims at collagen with simple structure and without excessive covalent bond crosslinking, and the collagen-containing waste treated by the tanning process cannot be easily dissolved due to the more complex molecular aggregation structure. An ionic liquid, which has recently been a focus, is a molten salt at room temperature, and shows excellent performance in dissolving a poorly soluble natural polymer. The subject group (patent No. 201010173659.9) successfully dissolved collagen fibers from leather-making waste leather scraps within 2h by adopting 1-butyl-3-methylimidazole chloride ([ BMIM ] Cl) for the first time, and prepared collagen functional materials with different forms by a precipitation regeneration method. However, the dissolution process requires a high temperature (100-120 ℃), which is not favorable for the stability of the molecular structure of the collagen. Although the ionic liquid shows excellent dissolving performance, the ionic liquid is not suitable for being used as an ideal solvent for biomass resources such as tanning waste to be recycled in large quantities.
The above drawbacks limit better recycling of tanning waste, and are technical problems to be solved in the art.
Disclosure of Invention
The invention aims to provide a method for dissolving collagen-containing waste in the leather industry, and simultaneously provides a method for preparing a porous membrane material.
Based on the purpose, the invention adopts the following technical scheme:
the dissolving method of collagen-containing waste in tanning industry comprises dissolving the collagen waste in a salt-water system selected from LiBr water solution and CaCl2-one of an ethanol-water solution, a NaSCN-water solution and a LiBr-dimethylsulfoxide-water solution.
The concentration of the LiBr aqueous solution is 2.3-9.3 mol/L; CaCl2-ethanol-CaCl in aqueous solution2The molar ratio of the ethanol to the water is 1 (2-5) to 7-8; the concentration of the NaSCN aqueous solution is 30-55 wt%; the molar ratio of LiBr, dimethyl sulfoxide and water in the LiBr-dimethyl sulfoxide-water solution is 1:2 (7-10).
The solid-liquid ratio of the collagen waste to the salt-water system is 1 (20-50), the dissolving temperature is 50-75 ℃, and the dissolving time is 24-60 hours.
The collagen waste is dried and mechanically crushed to obtain the collagen fiber, and then the collagen fiber is dissolved in a salt-water system.
The drying temperature is between room temperature and 50 ℃.
The collagen waste is leftover waste produced by animal skin after being treated by degreasing, liming and deliming processes.
The animal skin is pigskin, cow leather or rabbit skin.
The preparation method of the porous membrane material comprises the following steps: 1) obtaining a protein solution by using the dissolving method; 2) and coating the obtained protein solution on the surface of a matrix material, and solidifying and regenerating the matrix material in a precipitator.
In the step 2), the precipitant is ethanol, acetone or isopropanol.
In the step 2), the matrix material is glass, ceramic, metal or a high polymer material.
The invention adopts a salt-water system dissolving method to recycle leather-making leather collagen waste, provides new solvent composition and dissolving conditions, and provides scientific basis and new thinking for recycling biomass waste resources and constructing novel leather rubber raw materials. Compared with the prior art, the invention has the technical advantages that:
(1) the invention processes the collagen waste in a dissolving way to construct a novel collagen-based material-porous membrane material which can be used for cell culture, catalysis and other aspects and is expected to realize high-value utilization of collagen biomass materials;
(2) compared with the ionic liquid and acid dissolution, the dissolution mode of the collagen waste is low in cost and high in solubility, and the molecular weight of the collagen obtained after dissolution is high;
(3) the method has simple steps, mild reaction conditions and strong operability, and is more favorable for industrial popularization.
Drawings
FIG. 1 is a photograph showing collagen fibers obtained by drying and mechanically pulverizing collagen waste;
FIG. 2 shows the reaction mixture being passed through an aqueous solution of LiBr, CaCl, respectively2-a physical photograph of the protein solution obtained by dissolving the aqueous ethanol solution and the NaSCN solution;
FIG. 3 is an SEM image of a porous membrane material prepared by the present invention;
FIG. 4 is a gel permeation chromatogram of protein solutions obtained by dissolving collagen fibers using different salt-water systems.
Detailed Description
The present invention will be specifically illustrated by the following examples, but these specific embodiments do not limit the scope of the present invention in any way. The raw materials used in this embodiment are all commercially available.
Example 1
The method for preparing the porous membrane material by utilizing the collagen-containing waste in the leather industry comprises the following steps:
1) dissolving collagen waste in a tanning industry in a salt-water system to obtain a protein solution; the collagen waste is dried in a blower at 50 deg.C, mechanically pulverized to obtain collagen fiber (shown in figure 1), and then dissolved in a salt-water system. The salt-water system is LiBr water solution with the concentration of 9.3 mol/L; the collagen waste is leftover waste generated after the cowhide is treated by degreasing, liming and deliming processes; the solid-liquid ratio of the collagen waste to the salt-water system is 1:50, the dissolving temperature is 50 ℃, and the dissolving time is 60 hours;
2) coating the obtained protein solution on the surface of a matrix material, and solidifying and regenerating in a precipitator to obtain a porous membrane material; the precipitant is ethanol. The matrix material is glass.
Example 2
The method for preparing the porous membrane material by utilizing the collagen-containing waste in the leather industry comprises the following steps:
1) dissolving collagen waste in a tanning industry in a salt-water system to obtain a protein solution; naturally drying the collagen waste at room temperature, mechanically crushing to obtain collagen fibers, and dissolving in a salt-water system; the salt-water system is 55wt% NaSCN water solution; the collagen waste is leftover waste generated after the cowhide is treated by degreasing, liming and deliming processes; the solid-liquid ratio of the collagen waste to the salt-water system is 1:20, the dissolving temperature is 50 ℃, and the dissolving time is 60 hours;
2) coating the obtained protein solution on the surface of a matrix material, and solidifying and regenerating in a precipitator to obtain a porous membrane material; the precipitant is acetone. The matrix material is ceramic (or polymer material such as polytetrafluoroethylene).
Example 3
The method for preparing the porous membrane material by utilizing the collagen-containing waste in the leather industry is different from the method in the embodiment 2 in that: in the step 1), the salt-water system is a 30wt% NaSCN water solution, the solid-to-liquid ratio of the collagen waste to the salt-water system is 1:50, the dissolving temperature is 75 ℃, and the dissolving time is 24 hours; the precipitating agent in the step 2) is isopropanol, the matrix material is metal, and the rest is the same as the embodiment 2.
Example 4
The method for preparing the porous membrane material by utilizing the collagen-containing waste in the leather industry is different from the method in the embodiment 1 in that: in the step 1), the salt-water system is LiBr water solution with the concentration of 2.3mol/L, the solid-liquid ratio of the collagen waste to the salt-water system is 1:20, the dissolving temperature is 75 ℃, and the dissolving time is 24 hours; the rest is the same as in example 1.
Example 5
The method for preparing the porous membrane material by utilizing the collagen-containing waste in the leather industry is different from the method in the embodiment 1 in that: in the step 1), the salt-water system is CaCl2-aqueous ethanol, said CaCl2The molar ratio of the ethanol to the water is 1:5: 7; the rest is the same as in example 1.
Example 6
The method for preparing the porous membrane material by utilizing the collagen-containing waste in the leather industry is different from the method in the embodiment 1 in that: in the step 1), the salt-water system is CaCl2-aqueous ethanol, said CaCl2The mol ratio of ethanol to water is 1:2:8, the solid-liquid ratio of the collagen waste to the salt-water system is 1:20, the dissolving temperature is 75 ℃, and the dissolving time is 24 hours; the rest is the same as in example 1.
Example 7
The method for preparing the porous membrane material by utilizing the collagen-containing waste in the leather industry is different from the method in the embodiment 1 in that: in the step 1), the salt-water system is LiBr-dimethyl sulfoxide-water solution, and the molar ratio of LiBr, dimethyl sulfoxide and water is 1:2: 7; the solid-liquid ratio of the collagen waste to the salt-water system is 1:20, the dissolving temperature is 50 ℃, and the dissolving time is 60 hours; the rest is the same as in example 1.
Example 8
The method for preparing the porous membrane material by utilizing the collagen-containing waste in the leather industry is different from the method in the embodiment 1 in that: in the step 1), the salt-water system is LiBr-dimethyl sulfoxide-water solution, and the molar ratio of LiBr, dimethyl sulfoxide and water is 1:2: 10; the solid-liquid ratio of the collagen waste to the salt-water system is 1:50, the dissolving temperature is 75 ℃, and the dissolving time is 24 hours; the rest is the same as in example 1.
Example 9
The method for preparing the porous membrane material by utilizing the collagen-containing waste in the leather industry is different from the method in the embodiment 1 in that: in the step 1), the salt-water system is 55wt% NaSCN aqueous solution, the dissolving temperature is 50 ℃, and the dissolving time is 60 hours; the rest is the same as in example 1.
Example 10
The method for preparing the porous membrane material by utilizing the collagen-containing waste in the leather industry is different from the method in the embodiment 1 in that: in the step 1), the salt-water system is a 30wt% NaSCN aqueous solution, the dissolving temperature is 75 ℃, and the dissolving time is 24 hours; the rest is the same as in example 1.
Effect test
1. Characterization of molecular weight
In order to investigate the effect on collagen molecular weight when collagen fibers were dissolved using the salt-water system of the present invention, the present test performed molecular weight characterization of the protein solutions obtained by dissolving in step 1) of examples 1, 5, 7 and 9 by gel permeation chromatography, and the obtained profile is shown in fig. 4, using the protein solution obtained by treating with 35wt% NaCl solution as a control in the prior art.
Through the analysis of the outflow time and the molecular weight standard curve, the molecular weight range of the dissolved protein is 5-11 ten thousand. The molecular weight of the protein obtained by the control group after being treated by NaCl solution is about 4 ten thousand. It can be seen that protein molecules are severely degraded after the NaCl solution treatment.
2. Solubility test
To investigate the degree of dissolution of collagen fibres using the salt-water system described in the present invention, the test was carried out using the following method: weighing the dissolved hide powder (collagen waste after drying and mechanical crushing), wherein the weight is m1, dissolving the hide powder in a salt-water system, centrifuging the dissolved hide powder, washing the dissolved hide powder with water, centrifuging the dissolved hide powder again, drying the dissolved hide powder, and weighing the dried hide powder as m 2.
And (3) calculating the solubility: solubility (%) = (m 1-m 2)/m 1 × 100%. The solubility results obtained with different salt-water systems are shown in table 1.
As can be seen from table 1, the salt-water system proposed in this example can improve the solubility of collagen fibers better than the prior art.
Next, FIG. 2 shows the reaction mixture of LiBr in water and CaCl in water2A photograph of a real object of a protein solution obtained by dissolving an aqueous ethanol solution and a NaSCN solution, the solution being homogeneous and clear, which further illustrates the inventionThe proposed salt solvent system has good dissolving capacity for the collagen of the skin.
Table 1 dissolution results with different salt-water systems
3. Scanning electron microscope test
Fig. 3 is an SEM image of the porous membrane material prepared by the present invention, and it can be seen from fig. 3 that collagen molecules of the prepared porous membrane material are rearranged to form a microfibril structure to be interwoven together, thereby forming a porous membrane structure. The porous membrane has the potential of being applied in the fields of catalysis, cell culture and the like.
Claims (9)
1. The dissolving method of the collagen-containing waste in the leather industry is characterized in that the collagen waste is dissolved in a salt-water system, wherein the salt-water system is selected from LiBr water solution and CaCl2-one of an ethanol-water solution, a NaSCN-water solution and a LiBr-dimethylsulfoxide-water solution;
the concentration of the LiBr aqueous solution is 2.3-9.3 mol/L; CaCl2-ethanol-CaCl in aqueous solution2The molar ratio of the ethanol to the water is 1 (2-5) to 7-8; the concentration of the NaSCN aqueous solution is 30-55 wt%; the molar ratio of LiBr, dimethyl sulfoxide and water in the LiBr-dimethyl sulfoxide-water solution is 1:2 (7-10).
2. The method for dissolving collagen-containing waste in leather industry according to claim 1, wherein the solid-to-liquid ratio of the collagen waste to the salt-water system is 1 (20-50), the dissolving temperature is 50-75 ℃, and the dissolving time is 24-60 hours.
3. The method of dissolving collagen-containing waste in the tanning industry as recited in claim 2, wherein the collagen waste is dried and mechanically crushed to obtain collagen fibers, and then dissolved in a salt-water system.
4. The method for dissolving collagen-containing waste in the tanning industry as recited in claim 3, wherein the drying temperature is from room temperature to 50 ℃.
5. The method for dissolving collagen-containing waste in tanning industry as recited in claim 4, wherein said collagen waste is leftover bits and pieces of animal skin after being treated by degreasing, liming, deliming processes.
6. The method of dissolving collagen-containing waste in the tanning industry as recited in claim 5, wherein said animal skin is selected from the group consisting of pigskin, cowskin and rabbit skin.
7. The preparation method of the porous membrane material is characterized by comprising the following steps: 1) obtaining a protein solution by the solubilization method of any one of claims 1-6; 2) and coating the obtained protein solution on the surface of a matrix material, and solidifying and regenerating the matrix material in a precipitator.
8. The method for preparing a porous membrane material according to claim 7, wherein in step 2), the precipitating agent is ethanol, acetone or isopropanol.
9. The method for preparing a porous membrane material according to claim 7, wherein in step 2), the matrix material is a glass, ceramic, metal or polymer material.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1487038A (en) * | 2003-08-07 | 2004-04-07 | 唐宝辉 | Biocollagen and its production process |
| CN101050308A (en) * | 2007-04-29 | 2007-10-10 | 温州大学 | Method for preparing new type leather from disused leather |
| CN102559952A (en) * | 2011-11-07 | 2012-07-11 | 四川大学 | Method for preparing protein stuffing for tanning with chrome-containing scrap leather from tanning |
| CN104672316A (en) * | 2015-02-11 | 2015-06-03 | 苏州丝美特生物技术有限公司 | Preparation and identification method of domestic silkworm silk fibroin solution |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1487038A (en) * | 2003-08-07 | 2004-04-07 | 唐宝辉 | Biocollagen and its production process |
| CN101050308A (en) * | 2007-04-29 | 2007-10-10 | 温州大学 | Method for preparing new type leather from disused leather |
| CN102559952A (en) * | 2011-11-07 | 2012-07-11 | 四川大学 | Method for preparing protein stuffing for tanning with chrome-containing scrap leather from tanning |
| CN104672316A (en) * | 2015-02-11 | 2015-06-03 | 苏州丝美特生物技术有限公司 | Preparation and identification method of domestic silkworm silk fibroin solution |
Non-Patent Citations (1)
| Title |
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| 碱-中性盐溶液中皮胶原纤维的水解;程海明等;《中国皮革》;20090903;第38卷(第17期);第8-11页 * |
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