Porous coordination polymer tanning agent as well as preparation method and application thereof

Abstract

The invention discloses a porous coordination polymer tanning agent and a preparation method and application thereof, and belongs to the technical field of leather tanning agents. According to the preparation method disclosed by the invention, a metal salt solution and an organic ligand solution are used as raw materials, and the porous coordination polymer tanning agent is prepared through calcination activation treatment; according to the method, dependence on an expensive organic solvent is avoided, the synthesis condition is changed from high temperature and high pressure to room temperature and normal pressure, energy consumption is reduced, and the risk of environmental pollution is remarkably reduced; meanwhile, the use of chromium ions is avoided, the reaction conditions of the porous coordination polymer tanning agent are moderated, and the organic solvent is removed, so that the pollution to the environment and the potential threat to the human health in the preparation process and the application process of the tanning agent are effectively reduced, and the requirement of large-scale production can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of leather tanning agents, and in particular relates to a porous coordination polymer tanning agent and a preparation method and application thereof. Background Art

[0002] During the tanning process, tanning agent molecules penetrate the animal hide from the outside to the inside, and combine with the active groups on the collagen fibers in the animal hide through coordination bonds, hydrogen bonds, etc., to obtain tanned leather with excellent wet heat stability and physical and mechanical properties. The leather products obtained by further processing of tanned leather are stable in storage, strong and durable, indicating that tanning can make efficient resource utilization of animal hides, which are the by-products of the food industry, and has extremely high economic significance. Chrome tanning agent (Cr(OH)SO4) has become the most widely used tanning agent due to its mature application process and best tanning performance. However, the absorption rate of chromium in chrome tanning agent is low, and a large amount of unused chromium is discharged with wastewater and waste leather. In addition, Cr(Ⅲ) in tanned leather is easily oxidized into carcinogenic Cr(Ⅵ) in the subsequent leather making process, posing a serious threat to environmental safety and human health. Therefore, the development of chrome-free tanning agents has become the most important research direction in the leather making industry.

[0003] Non-chromium metal (zirconium, aluminum, iron, etc.) tanning agents can form relatively stable chemical cross-links with skin collagen fibers through coordination bonds, which can give tanned leather certain wet heat stability and physical and mechanical properties. They are currently a relatively mature type of chrome-free tanning agent. However, metal ions usually exist in the form of water complexes in water, and the stability of the complexes greatly affects the tanning properties of metal tanning agents. For example, zirconium ions are easily hydrolyzed and polymerized to form polymers, and their large molecular weight affects the ability of tanning agent molecules to penetrate into raw hides; aluminum ions have a weaker ability to bind to skin collagen fibers, and are more likely to form coordination compounds with water, causing tanned leather to detannage when exposed to water. At present, the introduction of small molecule organic ligands to form relatively stable coordination compounds with metal tanning agents can improve the tanning properties of metal tanning agents.

[0004] Coordination polymers such as complexes of hyperbranched polymers and metal salts and metal-organic framework materials are good tanning materials. However, conventional synthesis methods of coordination polymer tanning agents use a large amount of organic solvents and are usually synthesized under high temperature and high pressure conditions. The process is complicated and difficult to scale up, which limits the application of this type of tanning agent. Summary of the invention

[0005] The purpose of the present invention is to provide a porous coordination polymer tanning agent and a preparation method and application thereof, so as to solve the technical problem that the existing preparation method has high requirements on synthesis conditions and is not conducive to large-scale production.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: The invention discloses a method for preparing a porous coordination polymer tanning agent, comprising the following steps: mixing the metal salt solution into the organic ligand solution, and stirring to obtain a mixed solution; The mixed solution is post-treated in sequence to obtain a powder product; The powder product is subjected to calcination and activation treatment to obtain a porous coordination polymer tanning agent.

[0007] Furthermore, the metal salt solution is obtained by mixing metal salt, acetic acid and water; the molar ratio of the metal salt, acetic acid and water is 1:(5-20):(100-200); The organic ligand solution is obtained by mixing an organic ligand, sodium hydroxide and water; the molar ratio of the organic ligand, sodium hydroxide and water is 1:(1-10):(200-300).

[0008] Furthermore, the metal salt is a zirconium salt, an aluminum salt, an iron salt or a zinc salt.

[0009] Furthermore, the molar ratio of the metal salt to the organic ligand in the mixed solution is 1:(0.5-5).

[0010] Furthermore, the organic ligand is a carboxylic acid ligand, a phosphate ligand or a nitrogen-containing heterocyclic ligand.

[0011] Furthermore, the post-treatment is centrifugation, washing and drying performed in sequence; the washing is performed using water and ethanol for 1 to 3 times respectively; and the drying temperature is 50 to 80°C.

[0012] Furthermore, the calcination activation treatment is carried out at a temperature of 150-300° C. and for a time of 6-24 hours.

[0013] The invention also discloses a porous coordination polymer tanning agent prepared by the preparation method.

[0014] The present invention also discloses the use of the porous coordination polymer tanning agent in leather tanning, which comprises the following steps: The pickled leather is taken as raw material, and the mass of the pickled leather is weighed as the reference mass of the tanning process; sodium chloride and water are added into a rotary drum, the mass of water is 100-200% of the reference mass, and the mass of sodium chloride is 6-10% of the reference mass; 0.5-2.5% of the reference mass of 10% formic acid solution is added, and the pH value of the solution in the rotary drum is adjusted to 1.0-3.5 to obtain a tanning bath; a porous coordination polymer tanning agent is added into the tanning bath, and tanning is performed for 1-6 h; after the tanning is completed, 0.5-2.5% of the reference mass of sodium bicarbonate solution is added, and the pH value of the tanning bath is adjusted to 3.5-6.0, and the leather is rotated for 30-90 min, left to stand overnight, and rotated for 30-90 min the next day to obtain a porous coordination polymer tanned leather.

[0015] Furthermore, the mass of the porous coordination polymer tanning agent is 1-10% of the reference mass.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The invention discloses a method for preparing a porous coordination polymer tanning agent. The porous coordination polymer tanning agent is prepared by using a metal salt solution and an organic ligand solution as raw materials and undergoing a calcination activation treatment. The method not only avoids dependence on expensive organic solvents, but also changes the synthesis conditions from high temperature and high pressure to room temperature and normal pressure, thereby reducing energy consumption and significantly reducing the risk of environmental pollution. At the same time, the use of chromium ions is avoided, and the mild reaction conditions of the porous coordination polymer tanning agent and the removal of organic solvents effectively reduce the pollution of the tanning agent to the environment during the preparation and application processes and the potential threat to human health, thereby meeting the requirements of large-scale production.

[0017] Furthermore, the metal salt and organic ligand raw materials used are easily available and cheap, while avoiding harsh reaction conditions and the use of expensive and toxic organic solvents, reducing the preparation cost of the tanning agent and facilitating the large-scale production of the tanning agent; in addition, the method of the present invention simplifies the application process of the tanning agent, and the process parameters are close to traditional chrome tanning, which is suitable for subsequent leather processing, is more conducive to the replacement of chrome tanning agents, and further highlights its advantages in industrial applications.

[0018] The present invention also discloses a porous coordination polymer tanning agent prepared by the above method. The prepared porous coordination polymer tanning agent has good permeability and can give tanned leather a higher shrinkage temperature after application. The organic ligands in the structure of the porous coordination polymer tanning agent can stabilize metal ions and promote the efficient use of metal ions, so that the porous coordination polymer tanned leather still has good wet heat stability and physical and mechanical properties at a lower metal content. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is the XRD spectrum of the porous coordination polymer tanning agent prepared in Example 1 of the present invention; Figure 2 The figure is a shrinkage temperature diagram of tanned leather obtained by using the porous coordination polymer tanning agent prepared by the present invention. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0021] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0022] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0023] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0024] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0025] The present invention provides a method for preparing a porous coordination polymer tanning agent, comprising the following steps: Step 1: dissolving a metal salt in an acetic acid aqueous solution (obtained by mixing acetic acid and water), and stirring thoroughly to obtain a metal salt solution; wherein the molar ratio of the metal salt, acetic acid, and water is 1:(5-20):(100-200); Step 2: dissolving the organic ligand in a sodium hydroxide aqueous solution (obtained by mixing sodium hydroxide and water), and stirring thoroughly to obtain an organic ligand solution, wherein the molar ratio of the organic ligand, sodium hydroxide, and water is 1:(1-10):(200-300); Step 3: Pour the metal salt solution obtained in step 1 into the organic ligand solution obtained in step 2, and stir to obtain a milky white mixed solution; centrifuge the mixed solution to obtain a crude product, wash it with water and ethanol for 1 to 3 times, and dry it at 60° C. to obtain a white powder product; Step 4: The powder product is further calcined and activated at 200°C for 12 hours to obtain a porous coordination polymer tanning agent synthesized at room temperature.

[0026] Preferably, the metal salt is a metal salt having tanning properties such as zirconium salt, aluminum salt, iron salt, zinc salt, etc.

[0027] Preferably, the organic ligand is a multi-coordinate ligand such as a carboxylic acid ligand, a phosphate ligand, or a nitrogen-containing heterocyclic ligand.

[0028] The porous coordination polymer tanning agent is applied in leather tanning, which specifically comprises the following steps: The pickled leather is taken as raw material, and the mass of the pickled leather is weighed as the reference mass of the tanning process; sodium chloride and water are added into a rotary drum, the mass of water is 100-200% of the reference mass, and the mass of sodium chloride is 6-10% of the reference mass; 0.5-2.5% of the reference mass of 10% formic acid solution is added, and the pH value of the solution in the rotary drum is adjusted to 1.0-3.5 to obtain a tanning bath; a porous coordination polymer tanning agent is added into the tanning bath, and tanning is performed for 1-6 h; after the tanning is completed, 0.5-2.5% of the reference mass of sodium bicarbonate solution is added, and the pH value of the tanning bath is adjusted to 3.5-6.0, and the leather is rotated for 30-90 min, left to stand overnight, and rotated for 30-90 min the next day to obtain a porous coordination polymer tanned leather.

[0029] Preferably, the mass of the porous coordination polymer tanning agent is 1-10% of the base mass.

[0030] The preparation method proposed in the present invention not only avoids dependence on organic solvents and reduces energy consumption, but also significantly reduces the risk of environmental pollution; in addition, the room temperature synthesis method of the porous coordination polymer tanning agent provided by the present invention has the advantages of simple operation, low energy consumption, and easy large-scale production. The tanning agent application process has strong repeatability and is compatible with subsequent traditional leather making processes, which helps to promote the leather making industry to develop in a more green and environmentally friendly direction.

[0031] The present invention adopts metal salts and organic ligands with tanning properties as raw materials, and uses environmentally friendly solvents to prepare porous coordination polymer tanning agents at room temperature; the stability and penetration capacity of the tanning agent are enhanced through the stabilizing effect of small molecule ligands on metal ions, effectively solving the problems of insufficient stability of traditional metal tanning agents and high energy consumption and difficulty in scalability in the synthesis process of traditional metal-organic framework materials.

[0032] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0033] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0034] Example 1 A method for preparing a porous coordination polymer tanning agent comprises the following steps: Step 1: dissolving zirconium salt zirconium oxychloride octahydrate in an acetic acid aqueous solution, and stirring thoroughly to obtain a metal salt solution, wherein the molar ratio of the metal salt, acetic acid, and water is 1:7:100; Step 2: dissolving the carboxylic acid ligand terephthalic acid in a sodium hydroxide aqueous solution, and stirring thoroughly to obtain an organic ligand solution, wherein the molar ratio of the organic ligand, sodium hydroxide, and water is 1:2:200; Step 3: Pour the metal salt solution obtained in step 1 into the organic ligand solution obtained in step 2, and stir to obtain a milky white mixed solution; centrifuge the mixed solution to obtain a crude product, wash it with water and ethanol three times respectively; and dry it at 60° C. to obtain a white powder product; Step 4: The powder product is further calcined and activated at 200° C. for 12 h to obtain a porous coordination polymer tanning agent.

[0035] Example 2 A method for preparing a porous coordination polymer tanning agent comprises the following steps: Step 1: dissolving zirconium salt zirconium oxychloride octahydrate in an acetic acid aqueous solution, and stirring thoroughly to obtain a metal salt solution, wherein the molar ratio of the metal salt, acetic acid, and water is 1:12:150; Step 2: dissolving the carboxylic acid ligand trimesic acid in a sodium hydroxide aqueous solution and stirring thoroughly to obtain an organic ligand solution, wherein the molar ratio of the organic ligand, sodium hydroxide, and water is 1:6:250; Step 3: Pour the metal salt solution obtained in step 1 into the organic ligand solution obtained in step 2, and stir to obtain a milky white mixed solution; centrifuge the mixed solution to obtain a crude product, wash it with water and ethanol three times respectively; and dry it at 60° C. to obtain a white powder product; Step 4: The powder product is further calcined and activated at 200° C. for 12 h to obtain a porous coordination polymer tanning agent.

[0036] Example 3 A method for preparing a porous coordination polymer tanning agent comprises the following steps: Step 1: dissolving zirconium salt zirconium chloride in an acetic acid aqueous solution and stirring thoroughly to obtain a metal salt solution, wherein the molar ratio of the metal salt, acetic acid, and water is 1:18:200; Step 2: dissolving the carboxylic acid ligand fumaric acid in a sodium hydroxide aqueous solution, and stirring thoroughly to obtain an organic ligand solution, wherein the molar ratio of the organic ligand, sodium hydroxide, and water is 1:9:300; Step 3: Pour the metal salt solution obtained in step 1 into the organic ligand solution obtained in step 2, and stir to obtain a milky white mixed solution; centrifuge the mixed solution to obtain a crude product, wash it with water and ethanol three times respectively; and dry it at 60° C. to obtain a white powder product; Step 4: The powder product is further calcined and activated at 200° C. for 12 h to obtain a porous coordination polymer tanning agent.

[0037] Example 4 A method for preparing a porous coordination polymer tanning agent comprises the following steps: Step 1: dissolving zinc salt zinc nitrate in an acetic acid aqueous solution, and stirring thoroughly to obtain a metal salt solution, wherein the molar ratio of the metal salt, acetic acid, and water is 1:10:170; Step 2: dissolving the nitrogen-containing heterocyclic ligand 2-methylimidazole in a sodium hydroxide aqueous solution, and stirring thoroughly to obtain an organic ligand solution, wherein the molar ratio of the organic ligand, sodium hydroxide, and water is 1:5:200; Step 3: Pour the metal salt solution obtained in step 1 into the organic ligand solution obtained in step 2, and stir to obtain a milky white mixed solution; centrifuge the mixed solution to obtain a crude product, wash it with water and ethanol three times respectively; and dry it at 60° C. to obtain a white powder product; Step 4: The powder product is further calcined and activated at 200° C. for 12 h to obtain a porous coordination polymer tanning agent.

[0038] Example 5 A method for preparing a porous coordination polymer tanning agent comprises the following steps: Step 1: dissolving zinc salt zinc nitrate in an acetic acid aqueous solution, and stirring thoroughly to obtain a metal salt solution, wherein the molar ratio of the metal salt, acetic acid, and water is 1:20:100; Step 2: dissolving the nitrogen-containing heterocyclic ligand 2-methylimidazole in a sodium hydroxide aqueous solution, and stirring thoroughly to obtain an organic ligand solution, wherein the molar ratio of the organic ligand, sodium hydroxide, and water is 1:1:200; Step 3: Pour the metal salt solution obtained in step 1 into the organic ligand solution obtained in step 2, and stir to obtain a milky white mixed solution; centrifuge the mixed solution to obtain a crude product, wash it with water and ethanol three times respectively; and dry it at 50° C. to obtain a white powder product; Step 4: The powder product is further calcined and activated at 300°C for 6 hours to obtain a porous coordination polymer tanning agent.

[0039] Example 6 A method for preparing a porous coordination polymer tanning agent comprises the following steps: Step 1: dissolving zinc salt zinc nitrate in an acetic acid aqueous solution, and stirring thoroughly to obtain a metal salt solution, wherein the molar ratio of the metal salt, acetic acid, and water is 1:5:200; Step 2: dissolving the nitrogen-containing heterocyclic ligand 2-methylimidazole in a sodium hydroxide aqueous solution, and stirring thoroughly to obtain an organic ligand solution, wherein the molar ratio of the organic ligand, sodium hydroxide, and water is 1:10:300; Step 3: Pour the metal salt solution obtained in step 1 into the organic ligand solution obtained in step 2, and stir to obtain a milky white mixed solution; centrifuge the mixed solution to obtain a crude product, wash it with water and ethanol three times respectively; and dry it at 80° C. to obtain a white powder product; Step 4: The powder product is further calcined and activated at 150° C. for 24 hours to obtain a porous coordination polymer tanning agent.

[0040] Application Example 1 Take pickled leather as raw material, weigh the mass of the pickled leather as the reference mass for the tanning process; add sodium chloride and water into a rotary drum, the mass of water is 150% of the reference mass, the mass of sodium chloride is 7% of the reference mass, add 1.5% of the reference mass of 10% formic acid solution, adjust the pH value of the solution in the rotary drum to 2.0, and obtain a tanning bath; add the porous coordination polymer tanning agent prepared in Example 1 to the tanning bath, and tan for 4 hours; after the tanning is complete, add 2.0% of the reference mass of sodium bicarbonate solution, adjust the pH value of the tanning bath to 5.0, rotate for 60 minutes, let it stand overnight, and rotate for 60 minutes the next day to obtain porous coordination polymer tanned leather.

[0041] Application Example 2 Take pickled leather as raw material, weigh the mass of the pickled leather as the reference mass for the tanning process; add sodium chloride and water into a rotary drum, the mass of water is 100% of the reference mass, the mass of sodium chloride is 6% of the reference mass, add 1.0% of the reference mass of 10% formic acid solution, adjust the pH value of the solution in the rotary drum to 3.0, and obtain a tanning bath; add the porous coordination polymer tanning agent prepared in Example 2 to the tanning bath, and tan for 5 hours; after the tanning is complete, add 1.5% of the reference mass of sodium bicarbonate solution, adjust the pH value of the tanning bath to 4.5, rotate for 90 minutes, let it stand overnight, and rotate for 90 minutes the next day to obtain porous coordination polymer tanned leather.

[0042] Application Example 3 Take pickled leather as raw material, weigh the mass of the pickled leather as the reference mass for the tanning process; add sodium chloride and water into a rotary drum, the mass of water is 200% of the reference mass, the mass of sodium chloride is 8% of the reference mass, add 2.5% of the reference mass of 10% formic acid solution, adjust the pH value of the solution in the rotary drum to 1.0, and obtain a tanning bath; add the porous coordination polymer tanning agent prepared in Example 3 to the tanning bath, and tan for 5 hours; after the tanning is complete, add 2.5% of the reference mass of sodium bicarbonate solution, adjust the pH value of the tanning bath to 5.0, rotate for 60 minutes, let it stand overnight, and rotate for 60 minutes the next day to obtain porous coordination polymer tanned leather.

[0043] Application Example 4 Take pickled leather as raw material, weigh the mass of the pickled leather as the reference mass for the tanning process; add sodium chloride and water into a rotary drum, the mass of water is 150% of the reference mass, the mass of sodium chloride is 7% of the reference mass, add 2.0% of the reference mass of 10% formic acid solution, adjust the pH value of the solution in the rotary drum to 1.5, and obtain a tanning bath; add the porous coordination polymer tanning agent prepared in Example 4 to the tanning bath, and tan for 4 hours; after the tanning is complete, add 2.0% of the reference mass of sodium bicarbonate solution, adjust the pH value of the tanning bath to 4.0, rotate for 60 minutes, let it stand overnight, and rotate for 60 minutes the next day to obtain porous coordination polymer tanned leather.

[0044] Figure 1 This is the XRD spectrum of the porous coordination polymer tanning agent prepared in Example 1. From the sharp characteristic diffraction peaks appearing in the figure, it can be seen that the porous coordination polymer tanning agent prepared by the room temperature synthesis method has a crystal structure similar to that of the metal organic framework material.

[0045] Figure 2 This is a graph of the shrinkage temperature of leather tanned using the porous coordination polymer in the example. It can be seen from the graph that when the porous coordination polymer tanning agent prepared in Example 1 is applied to leather tanning, the shrinkage temperature of the tanned leather can be increased by more than 30°C compared to the untanned leather sample, indicating that the porous coordination polymer tanning agent synthesized at room temperature has good tanning properties.

[0046] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a porous coordination polymer tanning agent, characterized in that: The following steps are involved: mixing the metal salt solution into the organic ligand solution, and stirring to obtain a mixed solution; The mixed solution is post-treated in sequence to obtain a powder product; The powder product is subjected to calcination and activation treatment to obtain a porous coordination polymer tanning agent.

2. The method for preparing a porous coordination polymer tanning agent according to claim 1, characterized in that: The metal salt solution is obtained by mixing metal salt, acetic acid and water; the molar ratio of the metal salt, acetic acid and water is 1: (5-20): (100-200); The organic ligand solution is obtained by mixing an organic ligand, sodium hydroxide and water; the molar ratio of the organic ligand, sodium hydroxide and water is 1:(1-10):(200-300).

3. The method for preparing a porous coordination polymer tanning agent according to claim 2, characterized in that: The metal salt is a zirconium salt, an aluminum salt, an iron salt or a zinc salt.

4. The method for preparing a porous coordination polymer tanning agent according to claim 2, characterized in that: The molar ratio of the metal salt to the organic ligand in the mixed solution is 1:(0.5-5).

5. The method for preparing a porous coordination polymer tanning agent according to claim 2, characterized in that: The organic ligand is a carboxylic acid ligand, a phosphoric acid ligand or a nitrogen-containing heterocyclic ligand.

6. The method for preparing a porous coordination polymer tanning agent according to claim 1, characterized in that: The post-treatment is centrifugation, washing and drying in sequence; the washing is performed using water and ethanol for 1 to 3 times respectively; the drying temperature is 50 to 80°C.

7. The method for preparing a porous coordination polymer tanning agent according to claim 1, characterized in that: The temperature of the calcination activation treatment is 150-300° C. and the time is 6-24 hours.

8. A porous coordination polymer tanning agent, characterized in that: The method is prepared by any one of claims 1 to 7.

9. Use of a porous coordination polymer tanning agent according to claim 8 in leather tanning, characterized in that: The following steps are involved: Taking pickled leather as raw material, weighing the mass of pickled leather as the reference mass of tanning process; adding sodium chloride and water into a rotary drum, wherein the mass of water is 100-200% of the reference mass, the mass of sodium chloride is 6-10% of the reference mass, adding 0.5-2.5% of the reference mass of 10% formic acid solution, adjusting the pH value of the solution in the rotary drum to 1.0-3.5, and obtaining a tanning bath liquid; Add a porous coordination polymer tanning agent to the tanning bath and tan for 1 to 6 hours. When the tanning is complete, add 0.5 to 2.5% of the standard mass of sodium bicarbonate solution, adjust the pH value of the tanning bath to 3.5 to 6.0, rotate for 30 to 90 minutes, let it stand overnight, and rotate for 30 to 90 minutes the next day to obtain porous coordination polymer tanned leather.

10. Use of a porous coordination polymer tanning agent in leather tanning according to claim 9, characterized in that: The mass of the porous coordination polymer tanning agent is 1-10% of the base mass.

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