Rosin-based coordination polymer thin film, and preparation method and application thereof

Abstract

The present application relates to a kind of rosin-based coordination polymer film and its preparation method and application.By dissolving hydrolysis maleic rosin in natural turpentine to obtain oil phase solution, it is added to the water phase solution containing metal ions on top, coordination reaction occurs at oil-water interface to form rosin-based coordination polymer film, and combined with porous base film to form composite film.The present application realizes the nanoscale processing of rosin product by interfacial molecular self-assembly, and the obtained nanocomposite film has good performance in organic solvent nanofiltration, can realize the separation of organic molecules and solvent recovery, and has great prospect in the separation and purification of organic mixtures in chemical, pharmaceutical, food and other industries.The present interfacial synthesis method is efficient and convenient, solvent is green and sustainable, reaction condition is mild and easy to scale up.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of chemical utilization of turpentine, and particularly relates to a rosin-based coordination film as well as a preparation method and application thereof. BACKGROUND

[0002] As a renewable biomass resource, rosin is widely used in various industrial fields such as coatings, papermaking, adhesives, and perfumes, and is an extremely important bulk forest chemical. China is the largest rosin producing country in the world, with an annual output accounting for about 60% of the global output. However, the level, added value, and variety of rosin deep processing products cannot meet the market demand. Even globally, the high-value utilization and high-end application development of rosin are very limited, and in most cases, rosin products are only used as additives. There is a lack of products with rosin as the main body. In recent years, through chemical modification of the unique tricyclic diterpene rigid skeleton and carboxyl functional groups of rosin molecules, rosin-based nanometer new materials have been prepared by molecular self-assembly, which brings new opportunities for rosin deep processing technology innovation and high-value utilization of rosin products. On the one hand, the tricyclic diterpene rigid physical structure of rosin has a stable spatial configuration and volume effect, which can provide mechanical support for nanometer self-assembly; on the other hand, the active sites such as carboxyl groups of rosin are easy to modify and form interactions between molecules, and then self-assemble to obtain nanometer materials. Yan et al. synthesized an ammonium oxide surfactant R-6-AO by chemical modification of the carboxyl group of rosin, which can be used as a high-efficiency emulsion stabilizer and small-molecule hydrogel agent. In the presence of R-6-AO, various oil phases can form stable gel emulsions, which have wide applicability; Zhai et al. successfully prepared a rosin anionic surfactant C 12 -MPA-Na, which can form nanometer spherical aggregates at a low concentration and is expected to be applied in oil extraction, cosmetics, industrial washing, and other fields. The above-mentioned molecular self-assembly technology helps rosin to break through the existing application limitations and provides the possibility for the preparation of high-value rosin-based new materials and the expansion of high-end applications, but it still has the following problems: 1) the existing rosin-based nanometer assembly is mainly based on weak hydrophilic and hydrophobic interactions, and its stability is difficult to adapt to actual application; 2) the nanometer level processing precision makes the design and preparation of rosin-based nanometer materials extremely challenging (such as nanometer thin film).

[0003] Nanofiltration is a green and low-carbon frontier separation technology, and the separation process does not change phase and can be operated at room temperature or lower temperature. Under pressure driving, nanofiltration technology realizes efficient separation of small organic molecules (200-1000 Da) by using the permeation selectivity of the membrane, but has higher requirements for the stability and structure precision of the membrane, especially the nano ultra-thin membrane has smaller mass transfer resistance, which can improve the separation efficiency and reduce the operation energy consumption, and shows broad prospects in the field of nanofiltration. If the rosin material is processed into a nano thin film by a self-assembly technology and used for nanofiltration separation, it is expected to expand the application of rosin nano materials in the field of high-tech, but no related research results have been reported. SUMMARY

[0004] The present application aims to overcome the above-mentioned defects, and provides a rosin-based coordination polymer thin film and a preparation method and application thereof. The rosin nano thin film is prepared by using an interface coordination assembly strategy, hydrolyzed maleic rosin is used as a ligand, transition metal ions are used as a crosslinking center, and a flexible and adjustable metal-organic coordination is used to assemble and prepare a nano ultra-thin film with a thickness of about 34-54 nm at the interface of an aqueous solution and an oil phase solution. The nano ultra-thin film is loaded on a polyacrylonitrile porous base film to obtain an ultra-thin composite film, and the ultra-thin composite film is used for separation of organic mixtures.

[0005] To achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0006] A preparation method of a rosin-based coordination polymer thin film comprises the following steps: a certain amount of maleic rosin and NaOH are respectively dissolved in ethanol until completely dissolved, then NaOH ethanol solution is added dropwise into the maleic rosin ethanol solution while stirring until the pH value of the solution is about 9-10, then the solution is refluxed in an 88℃ oil bath for 6h, after cooling, the solution is extracted and washed with ethanol, and dried to obtain a light yellow solid, then the light yellow solid is dissolved in a proper amount of ultrapure water, and a proper amount of HCl solution is added dropwise while stirring until the pH value of the solution is about 3-4, then the solution is extracted and washed with ultrapure water, and dried to obtain a white powder, which is hydrolyzed maleic rosin. Then, a transition metal salt and the hydrolyzed maleic rosin are respectively dissolved in pure water and turpentine to configure an aqueous solution (1.25-5.0mmol / L) and an oil phase solution (0.25-1.0mg / mL), then the aqueous solution and the oil phase solution are sequentially poured into a glass container to react for 30-90min, and the rosin-based coordination polymer thin film is formed at the oil-water interface. The rosin-based thin film is taken up by a polyacrylonitrile base film, and the ultra-thin composite film is formed by heat treatment at 50-80℃ for 10min, and the ultra-thin composite film is applied to nanofiltration of organic solvents to realize separation of small molecule mixtures such as dyes, antibiotics and organic solvents.

[0007] Further, the transition metal salt is any one of copper sulfate, ferric chloride and zirconium nitrate. Preferably, the transition metal salt is ferric chloride.

[0008] Further, the concentration of the prepared transition metal salt aqueous phase assembly solution is preferably 5.0 mmol / L.

[0009] Further, the concentration of the prepared maleic rosin assembly solution is preferably 1.0 mg / mL.

[0010] Further, the time for two-phase solution assembly is preferably 60 min.

[0011] Compared with the prior art, the present application has the advantages of:

[0012] (1) The present application proposes an interface coordination processing method for rosin, which uses the interface self-assembly technology to prepare rosin-based coordination polymer thin films with a film thickness as low as nanometers.

[0013] (2) The rosin-based coordination polymer thin films prepared by the present application are very thin and have hydrophobic properties, and exhibit excellent performance in the field of organic mixture separation.

[0014] (3) The present application uses turpentine oil produced from rosin homologous to replace petroleum-based solvents, which is beneficial to ligand dissolution and is green and sustainable. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The surface electron microscope (SEM) image of the rosin-based coordination (iron ion) composite film prepared in Example 1.

[0016] Figure 2 The electron microscope (AFM) image of the rosin-based coordination (iron ion) polymer thin film (loaded on a silicon wafer substrate) prepared in Example 1.

[0017] Figure 3 The electron microscope (SEM) image of the surface of the commercial polyacrylonitrile-based film used in the present application.

[0018] Figure 4 The filtration of tetracycline, congo red, and alizarine blue 8GX organic molecules by the rosin-based coordination polymer thin film loaded on the PAN substrate prepared in Examples 1-3. DETAILED DESCRIPTION

[0019] The present application will be further described below through specific examples and drawings. The examples of the present application are to better enable those skilled in the art to understand the present application and do not limit the present application in any way.

[0020] Example 1, preparation of rosin-based coordination polymer thin film, the steps are as follows:

[0021] Step one, preparation of aqueous solution: add ferric chloride with a final concentration of 5 mmol / L to 80 mL of ultrapure water to prepare an aqueous phase assembly solution.

[0022] Step two, preparation of hydrolyzed maleic rosin solution: add hydrolyzed maleic rosin with final concentration of 1.0 mg / mL into 80 mL of turpentine oil to make oil phase assembly solution;

[0023] Step three, preparation of rosin-based coordination composite film: fix the washed and dried polyacrylonitrile-based film at the bottom of vacuum filtration device, add the water phase solution prepared in step one and the hydrolyzed maleic rosin assembly solution prepared in step two in sequence at the upper part, stand for assembly at 40℃ for 60 min, then open the vacuum filtration device for filtration until no water phase solution drops at the bottom, pour out the hydrolyzed maleic rosin assembly solution from the upper part, immerse the prepared assembly composite film in turpentine oil for 10 min, take out the film for heat treatment at 60℃ for 10 min to obtain rosin-based coordination composite film 1, the electron microscope graph of which is shown in Figure 1 .

[0024] Then use the obtained rosin-based coordination composite film for separation of tetracycline, congo red and alizarin blue.

[0025] Finally, add the water phase solution prepared in step one and the hydrolyzed maleic rosin assembly solution prepared in step two in sequence into 60 mL of round culture dish, stand for assembly at 40℃ for 60 min, take out the formed rosin-based coordination polymer film from the culture dish with forceps, and heat treat at 60℃ for 10 min to obtain rosin-based coordination polymer film, the thickness of which is confirmed by AFM electron microscope graph, as shown in Figure 2 .

[0026] The retention rate of the rosin-based coordination composite film 1 prepared in Example 1 for tetracycline (50 ppm) ethanol solution is 25.9%.

[0027] The retention rate of the rosin-based coordination composite film 1 prepared in Example 1 for congo red (50 ppm) ethanol solution is 37.7%.

[0028] The retention rate of the rosin-based coordination composite film 1 prepared in Example 1 for alizarin blue (50 ppm) ethanol solution is 99.3%.

[0029] Example 2, preparation of rosin-based coordination composite film, the preparation process of which is basically the same as that of Example 1, except that the water phase solution of transition metal ions in step one is changed from 5 mmol / L of ferric chloride aqueous solution to 5 mmol / L of copper sulfate aqueous solution, and finally rosin-based coordination composite film 2 is obtained.

[0030] The retention rate of the rosin-based coordination composite film 2 prepared in Example 2 for tetracycline (50 ppm) ethanol solution is 10.8%.

[0031] The retention rate of the rosin-based coordination composite membrane 2 prepared in Example 2 for a Congo red (50 ppm) ethanol solution was 30.3%.

[0032] The retention rate of the rosin-based coordination composite membrane 2 prepared in Example 2 for an Alizarine blue (50 ppm) ethanol solution was 98.7%.

[0033] Example 3, preparation of a rosin-based coordination composite membrane, the preparation process is basically the same as that of Example 1, the only difference is that the aqueous solution of transition metal ions in step one is changed from 5 mmol / L of ferric chloride aqueous solution to 5 mmol / L of zirconium nitrate aqueous solution, and finally a rosin-based coordination composite membrane 3 is obtained.

[0034] The retention rate of the rosin-based coordination composite membrane 3 prepared in Example 3 for a tetracycline (50 ppm) ethanol solution was 35.4%.

[0035] The retention rate of the rosin-based coordination composite membrane 3 prepared in Example 3 for a Congo red (50 ppm) ethanol solution was 53.0%.

[0036] The retention rate of the rosin-based coordination composite membrane 3 prepared in Example 3 for an Alizarine blue (50 ppm) ethanol solution was 99.8%.

[0037] Figure 4 The retention rate of the rosin-based coordination composite membranes 1-3 for tetracycline, Congo red, and Alizarine blue (50 ppm) ethanol solutions is shown in the figure.

[0038] Example 4, preparation of a rosin-based coordination composite membrane, the preparation process is basically the same as that of Example 1, the only difference is that the final concentration of the ferric chloride aqueous solution in step one is changed to 2.5 mmol / L, and finally a rosin-based coordination composite membrane 4 is obtained.

[0039] The retention rate of the rosin-based coordination composite membrane 4 prepared in Example 4 for a tetracycline (50 ppm) ethanol solution was 20.8%.

[0040] The retention rate of the rosin-based coordination composite membrane 4 prepared in Example 4 for a Congo red (50 ppm) ethanol solution was 30.6%.

[0041] The retention rate of the rosin-based coordination composite membrane 4 prepared in Example 4 for an Alizarine blue (50 ppm) ethanol solution was 99.8%.

[0042] Example 5, preparation of a rosin-based coordination composite membrane, the preparation process is basically the same as that of Example 1, the only difference is that the final concentration of the ferric chloride aqueous solution in step one is changed to 1.25 mmol / L, and finally a rosin-based coordination composite membrane 5 is obtained.

[0043] The rejection rate of tetracycline (50 ppm) ethanol solution by the rosin-based coordination composite membrane 5 prepared in Example 5 was 19.8%.

[0044] The rejection rate of Congo red (50 ppm) ethanol solution by the rosin-based coordination composite membrane 5 prepared in Example 5 was 27.8%.

[0045] The rejection rate of Alcian blue (50 ppm) ethanol solution by the rosin-based coordination composite membrane 5 prepared in Example 5 was 98.8%.

[0046] Example 6, a rosin-based coordination composite membrane was prepared according to the same procedure as in Example 1, except that the final concentration of hydrolyzed maleic rosin in Step 2 was changed to 0.5 mg / mL, and a rosin-based coordination composite membrane 6 was finally obtained.

[0047] The rejection rate of tetracycline (50 ppm) ethanol solution by the rosin-based coordination composite membrane 6 prepared in Example 6 was 20.1%.

[0048] The rejection rate of Congo red (50 ppm) ethanol solution by the rosin-based coordination composite membrane 6 prepared in Example 6 was 25.3%.

[0049] The rejection rate of Alcian blue (50 ppm) ethanol solution by the rosin-based coordination composite membrane 6 prepared in Example 6 was 98.2%.

[0050] Example 7, a rosin-based coordination composite membrane was prepared according to the same procedure as in Example 1, except that the final concentration of hydrolyzed maleic rosin in Step 2 was changed to 0.25 mg / mL, and a rosin-based coordination composite membrane 7 was finally obtained.

[0051] The rejection rate of tetracycline (50 ppm) ethanol solution by the rosin-based coordination composite membrane 7 prepared in Example 7 was 19.6%.

[0052] The rejection rate of Congo red (50 ppm) ethanol solution by the rosin-based coordination composite membrane 7 prepared in Example 7 was 22.4%.

[0053] The rejection rate of Alcian blue (50 ppm) ethanol solution by the rosin-based coordination composite membrane 7 prepared in Example 7 was 98.3%.

[0054] Example 8, a rosin-based coordination composite membrane was prepared according to the same procedure as in Example 1, except that the assembly time of the aqueous solution and the hydrolyzed maleic rosin assembly solution in Step 3 was changed from 60 min at 40°C to 30 min, and a rosin-based coordination composite membrane 8 was finally obtained.

[0055] The rejection rate of tetracycline (50 ppm) ethanol solution by the rosin-based coordination composite membrane 8 prepared in Example 8 was 20.3%.

[0056] The rejection rate of the rosin-based coordination composite membrane 8 prepared in Example 8 for a Congo red (50 ppm) ethanol solution was 24.6%.

[0057] The rejection rate of the rosin-based coordination composite membrane 8 prepared in Example 8 for an Alcian blue (50 ppm) ethanol solution was 98%.

[0058] Example 9, a rosin-based coordination composite membrane was prepared in the same manner as in Example 1, except that in Step 3, the assembly time of the aqueous solution and the hydrolyzed maleic rosin assembly solution was changed from 60 min at 40°C to 90 min, and finally a rosin-based coordination composite membrane 9 was obtained.

[0059] The rejection rate of the rosin-based coordination composite membrane 9 prepared in Example 9 for a tetracycline (50 ppm) ethanol solution was 26.1%.

[0060] The rejection rate of the rosin-based coordination composite membrane 9 prepared in Example 9 for a Congo red (50 ppm) ethanol solution was 31.7%.

[0061] The rejection rate of the rosin-based coordination composite membrane 9 prepared in Example 9 for an Alcian blue (50 ppm) ethanol solution was 98.5%.

[0062] Example 10, a rosin-based coordination composite membrane was prepared in the same manner as in Example 1, except that in Step 3, the heat treatment conditions of the prepared composite membrane were changed from heat treatment at 60°C for 10 min to heat treatment at 50°C for 10 min, and finally a rosin-based coordination composite membrane 10 was obtained.

[0063] The rejection rate of the rosin-based coordination composite membrane 10 prepared in Example 10 for a tetracycline (50 ppm) ethanol solution was 25.2%.

[0064] The rejection rate of the rosin-based coordination composite membrane 10 prepared in Example 10 for a Congo red (50 ppm) ethanol solution was 30.1%.

[0065] The rejection rate of the rosin-based coordination composite membrane 10 prepared in Example 10 for an Alcian blue (50 ppm) ethanol solution was 97.4%.

[0066] Example 11, a rosin-based coordination composite membrane was prepared in the same manner as in Example 1, except that in Step 3, the heat treatment conditions of the prepared composite membrane were changed from heat treatment at 60°C for 10 min to heat treatment at 70°C for 10 min, and finally a rosin-based coordination composite membrane 11 was obtained.

[0067] The retention rate of the rosin-based coordination composite membrane 11 prepared in Example 11 for tetracycline (50 ppm) ethanol solution is 26.3%.

[0068] The retention rate of the rosin-based coordination composite membrane 11 prepared in Example 11 for Congo red (50 ppm) ethanol solution is 32.3%.

[0069] The retention rate of the rosin-based coordination composite membrane 11 prepared in Example 11 for Alizarine blue (50 ppm) ethanol solution is 97.9%.

[0070] Example 12, preparation of a rosin-based coordination composite membrane, the preparation process is basically the same as that of Example 1, except that in step three, the heat treatment condition of the prepared composite membrane is changed from heat treatment at 60℃ for 10 min to heat treatment at 80℃ for 10 min, and finally a rosin-based coordination composite membrane 12 is obtained.

[0071] The retention rate of the rosin-based coordination composite membrane 12 prepared in Example 12 for tetracycline (50 ppm) ethanol solution is 27.9%.

[0072] The retention rate of the rosin-based coordination composite membrane 12 prepared in Example 12 for Congo red (50 ppm) ethanol solution is 30.5%.

[0073] The retention rate of the rosin-based coordination composite membrane 12 prepared in Example 12 for Alizarine blue (50 ppm) ethanol solution is 98.8%.

[0074] The comparative example selects a commercial polyacrylonitrile membrane, i.e. a comparative membrane, the surface electron microscope image of which is shown in Figure 3 .

[0075] The retention rate of the comparative membrane selected in the comparative example for tetracycline (50 ppm) ethanol solution is 7.9%.

[0076] The retention rate of the comparative membrane selected in the comparative example for Congo red (50 ppm) ethanol solution is 8.5%.

[0077] The retention rate of the comparative membrane selected in the comparative example for Alizarine blue (50 ppm) ethanol solution is 9.8%.

[0078] The separation performance of the membranes prepared in the examples of the present application and the comparative membrane for organic small molecules is shown in Table 1:

[0079] Table 1

[0080]

[0081]

[0082] Through the above examples, the present application obtains the corresponding experimental results.

[0083] According to the data in Table 1, during the preparation of the rosin-based coordination polymer film of this invention: 1. When the concentration of the hydrolyzed maleic rosin ligand solution decreases, the retention rates of tetracycline, Congo red, and Alcian blue decrease; 2. When coordinated with solutions of different types of transition metal ions, the retention rates of the three dyes are ranked as follows: copper sulfate < ferric chloride < zirconium nitrate; 3. When the concentration of the ferric chloride aqueous solution decreases, the retention rates of tetracycline, Congo red, and Alcian blue decrease; 4. When the assembly time increases, the retention rates of tetracycline, Congo red, and Alcian blue increase.

[0084] Depend on Figure 1 and Figure 2 As can be seen, in Example 1, the transition metal salt ferric chloride can coordinate with the rosin ligand to obtain a complete and continuous film structure. The assembled rosin-based coordination polymer film is uniformly loaded on the polyacrylonitrile-based film, and the film has a smooth and flat surface morphology with a thickness of about 49.5 nanometers.

[0085] Depend on Figure 4 As can be seen, the rosin-based coordination composite membranes prepared in Examples 1-3 were used to test the retention rates of common organic dyes of different molecular weights, including tetracycline (444 Da), Congo red (697 Da), and Alcian blue (1299 Da). The results showed that the coordination membranes formed by the three metal ions exhibited different retention rates for the three dyes. Furthermore, the membranes formed by ligands with higher concentrations of coordinating groups and metal ions exhibited higher retention rates and better separation performance for organic dyes.

[0086] It should be understood that the embodiments and examples discussed herein are for illustrative purposes only, and may be modified or altered by those skilled in the art, and all such modifications and alterations should fall within the scope of protection of the appended claims.

Claims

1. A process for the preparation of a rosin-based coordination polymer thin film, characterized in that, The transition metal salt and the hydrolyzed maleic rosin are dissolved in pure water and turpentine respectively to form an aqueous solution and an oil solution, and then the aqueous solution and the oil solution are poured into a glass container in sequence and reacted for a period of time, and the rosin-based coordination polymer film is formed at the oil-water interface; the rosin-based coordination polymer film is lifted by a polyacrylonitrile-based film and heat treated to be applied to organic solvent nanofiltration in the form of a composite film, so that organic small molecule mixtures are separated; The transition metal salt is any one of copper sulfate, ferric chloride and zirconium nitrate; The concentration of the transition metal salt in the aqueous solution is 1.25-5.0 mmol / L; The concentration of the hydrolyzed maleic rosin in the oil solution is 0.25-1.0 mg / mL; The reaction time is 30-90 min; The heat treatment temperature is 50-80℃, and the time is 10 min.

2. The rosin-based coordination polymer film prepared by the preparation method in claim 1.

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