Process for the preparation of dye / salt separation membranes based on co-deposition of dopamine and polymeric framework materials

Abstract

The present application relates to a method for preparing a dye / salt separation membrane based on co-deposition of dopamine and a polymer framework material; a polyacrylonitrile ultrafiltration membrane is hydrolyzed in an aqueous sodium hydroxide solution and then placed in deionized water to obtain a hydrolyzed polyacrylonitrile ultrafiltration membrane; an aqueous tris solution is prepared, hydrochloric acid is added to adjust the pH to 8-10, and a hydrochloric acid-tris solution with a concentration of 0.25-1.00 g / L is obtained; the polymer framework is added to the hydrochloric acid-tris buffer solution and ultrasonically dispersed to obtain a hydrochloric acid-tris solution of the polymer framework; the hydrochloric acid-tris solution of the polymer framework is mixed with anhydrous copper sulfate, hydrogen peroxide and dopamine, stirred, and then the mixed solution is poured onto the surface of the HPAN base membrane, and after static deposition, a dye / salt separation membrane co-deposited with dopamine and the polymer framework is obtained. The separation membrane exhibits excellent rejection performance for molecules with a molecular weight greater than 696.66 Da.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of loose nanofiltration membrane preparation; and relates to a method for preparing a dye / salt separation membrane based on co-deposition of dopamine and a polymer framework material (HMMP-1). BACKGROUND

[0002] The hierarchical treatment of dyes / salts is an important part of solving the pollution problem of textile wastewater, realizing resource recycling and sustainable development [1,2] . Compared with traditional dye / salt wastewater treatment technologies (e.g. adsorption, distillation, condensation, etc.), nanofiltration membrane separation technology has the advantages of low energy consumption, small occupation area, no secondary pollution, etc., and therefore is highly concerned in the field of textile wastewater treatment [3-5] . However, the existing commercial nanofiltration membranes are mainly prepared by interfacial polymerization process. Although the dense separation layer can maintain high rejection of dye molecules when treating high-salt dye wastewater, the rejection rate of monovalent and divalent salts is generally more than 30%, so it cannot realize effective separation of dyes and salts.

[0003] To realize effective separation of dyes and salts, Van et al. [5] first proposed the concept of loose nanofiltration membrane (LNM) and used it for wastewater treatment. So far, LNM has been mainly prepared by blending phase inversion [6-10] , interfacial polymerization [11-15] and surface coating construction [16-20] . Compared with other methods, surface coating construction can not only effectively avoid the problem of poor interfacial compatibility between nanofillers and mixed matrix existing in blending phase inversion, but also has simple preparation process, so it has broad application potential. The polydopamine deposition technology inspired by mussels has been widely used for the construction of surface coating due to its good biocompatibility, inherent adhesion and excellent multifunctionality. Zhu et al.

[21] used FeCl3 / H2O2 as initiator to successfully prepare a continuous and uniform polydopamine (PDA) coating within 1h. The results showed that the prepared LNM not only maintained high water permeability (17.5 LMH·bar -1 ), but also had a dye / salt (CR / Na2SO4) selectivity of 6.6. Wang et al.

[22] The polyethyleneimine (PEI) was introduced into the polydopamine coating to construct the polydopamine / polyethyleneimine hybrid coating. By adding Cu2SO4 / H2O2 into the polydopamine / polyethyleneimine solution, the polymerization of dopamine was promoted, and the Michael addition and Schiff base reaction between dopamine and polyethyleneimine were also facilitated, so that the rapid co-deposition of polydopamine / polyethyleneimine was successfully achieved. The introduction of polyethyleneimine can increase the space between the stacked polymer segments in the LNM separation layer on the one hand, and on the other hand, the introduction of positively charged amine groups can not only improve the hydrophilicity of the LNM surface, but also balance the negative charge of polydopamine, which is conducive to the preparation of electrically neutral LNM. The optimal LNM prepared has a water permeability of 26.2 LMH·bar -1 , and the selectivity of dye / salt (CR / Na2SO4) is further improved to 19.4. The above reported work essentially increases the gap between the stacked polymer segments in the LNM separation layer by introducing amine-rich polymers into the polydopamine coating to improve the permeation and selectivity of the membrane. However, due to the close packing of polymer segments, the free volume between the segments is characterized by small amount and wide distribution, so this method of increasing the gap between the stacked polymer segments to improve the performance of the membrane is still not ideal, and the water permeability of the prepared membrane is generally less than 30 LMH·bar -1 , and the selectivity of dye / salt is still less than 20.

[0004] The polymer framework material (HMMP-1) is composed of chromium nitrate nonahydrate, 4-chloroisophthalic acid and polyethyleneimine. Cr 3+ is first coordinated with 4-chloroisophthalic acid to form a unit cell, and then self-assembles along the polymer chain to form a three-dimensional framework structure [23-24] . SUMMARY

[0005] According to the deficiencies of the prior art, we have carried out in-depth research. The introduction of porous nanofillers can provide more water / salt transfer channels for the membrane separation layer, shorten the mass transfer distance, and further improve the permeation and selectivity of the prepared membrane. However, at the same time, the introduction of nanofillers will also bring the problem of compatibility with the mixed matrix interface. The polymer framework has a high specific surface area and a suitable pore size, and its co-deposition with dopamine can provide additional transport channels for water / salt in the separation layer, thereby breaking the limitation of the close packing of polymer segments on the performance of the membrane, and is expected to further improve the permeation and selectivity of the prepared membrane. In addition, the amine-rich polymer framework can form covalent bonds with dopamine through Michael addition / Schiff base reaction, effectively avoiding the problem of reduced permeation selectivity due to poor interface compatibility. The specific surface area of the polymer framework material is as high as 787.84 m 2 ·g -1It also has a suitable pore size (0.9 nm) between most hydrated ions and dye molecules. Therefore, more accurate nanochannels can be provided after introducing the membrane separation layer, breaking the limitation of the improvement of membrane performance due to the close packing of polymer segments. On the other hand, the polymer framework also has a rich free amine group, so it can form a covalent connection with dopamine through Michael addition / shiff base reaction, which can well avoid the problem of membrane performance decline due to poor interface compatibility. Therefore, co-deposition of dopamine and polymer framework material to break the limitation of the improvement of membrane performance due to the close packing of polymer segments is a key problem that needs to be solved urgently for preparing high-performance dye / salt separation membrane.

[0006] The present application proposes the following technical solutions:

[0007] A method for preparing a high-selectivity dye / salt separation membrane based on co-deposition of dopamine and polymer framework material, comprising the following steps:

[0008] 1) Hydrolyze the polyacrylonitrile ultrafiltration membrane (PAN) in a sodium hydroxide aqueous solution and then place it in deionized water to obtain a hydrolyzed polyacrylonitrile ultrafiltration membrane (HPAN);

[0009] 2) Prepare a tris aqueous solution, add hydrochloric acid to adjust the pH to 8-10 to obtain a hydrochloric acid-tris solution;

[0010] 3) Ultrasonically disperse the polymer framework into the hydrochloric acid-tris buffer solution of step 2) to obtain a hydrochloric acid-tris solution of the polymer framework;

[0011] 4) Mix and stir the hydrochloric acid-tris solution of the polymer framework of step 3) with anhydrous copper sulfate, hydrogen peroxide and dopamine, pour the above mixed solution onto the surface of the HPAN base membrane obtained in step 1), and after static deposition, obtain a dye / salt separation membrane co-deposited with dopamine and a polymer framework.

[0012] The concentration of the polymer framework in the hydrochloric acid-tris solution of the polymer framework in step 3) is 0.25-1.00 g / L.

[0013] The calculation method of the polymer framework concentration in step 3) refers to the following formula:

[0014] C = m / V

[0015] In the formula, C is the concentration of the polymer framework, g / L; m is the mass of the polymer framework, g; and V is the volume of the hydrochloric acid-tris, L.

[0016] The addition concentration of anhydrous copper sulfate in step 4) is 5-20 mM.

[0017] The concentration of hydrogen peroxide added in step 4) is 30-70 mM.

[0018] The concentration of dopamine added in step 4) is 108-653 mM.

[0019] The concentration of anhydrous copper sulfate, hydrogen peroxide, and dopamine added in step 4) is calculated based on the volume of hydrochloric acid-tris of the polymer framework.

[0020] The specific instructions are as follows:

[0021] The preparation method of the polymer framework in step 3) is referred to the invention patent "Mixed matrix membranes for CO2 separations by incorporating microporous polymer framework fillers with amine-rich nanochannels", document DOI: 10.1016 / j.memsci.2020.118923. The preparation method of the polymer framework in other public documents is also referred to.

[0022] The present application obtains a series of dye / salt separation membranes with high permeation selectivity by controlling the addition concentration of the polymer framework to be 0.25-1.00 g / L. The influence of nanoparticles on the membrane structure is determined by analyzing the surface SEM image of the polydopamine / polymer framework mixed coating. Within the addition concentration range contained in the present application, with the increase of the polymer framework concentration, the particle aggregates formed by the non-covalent polymerization of dopamine on the membrane surface are gradually replaced by the polymer framework particle aggregates. The disappearance of the particle aggregates formed by the non-covalent polymerization of dopamine is mainly because the introduction of the polymer framework rich in amine groups can form covalent connection with dopamine, thereby weakening the non-covalent connection between dopamines. In addition, the increase of the polymer framework concentration will intensify the crosslinking reaction with dopamine on the one hand, thereby increasing the deposition speed of dopamine and polymer framework, making the thickness of the prepared membrane further increase, which is not conducive to the improvement of permeability. On the other hand, the increase of the polymer framework concentration will intensify the agglomeration of nanoparticles, which is not conducive to the good dispersion of nanoparticles when the concentration exceeds a certain degree. The key steps are step 3 and step 4 of the above technical method, and the key parameter is the addition concentration of the polymer framework in step 3. When the polymer framework concentration exceeds 1.00 g / L, on the one hand, a large number of nanoparticles will agglomerate on the membrane surface, which is not conducive to the improvement of the membrane permeation selectivity. On the other hand, the polymer framework will accelerate the deposition after establishing covalent connection with dopamine, making the membrane thickness increase greatly, which is not conducive to the further improvement of the membrane performance; when the polymer framework concentration is lower than 0.25 g / L, the separation layer of the prepared membrane will form non-covalent aggregates of dopamine, making the stability and uniformity of the coating decrease. In addition, the polydopamine coating has less free volume and widely distributed due to the close packing and mutual folding of the polymer chains, so the permeation selectivity performance is still not ideal. The prepared loose nanofiltration membrane is subjected to pure water, 1.00 g / L salt solution and CR filtration experiments in turn. The results show that the pure water permeability of the optimal membrane prepared by adding 0.25 g / L of polymer is 57.22 LMH·bar -1 , which is 1.65 times that of the pure polydopamine membrane, and maintains a retention rate of 99.43% for CR. Then, different types of dyes (coomassie brilliant blue, direct red 23, congo red, sunset yellow, rhodamine B) are subjected to filtration experiments, and the results show that the prepared separation membrane exhibits excellent retention performance for molecules with a molecular weight greater than 696.66 Da. In addition, the prepared membrane is subjected to filtration experiments in different concentrations of dye / salt mixed systems (CR: 30 mg / L, NaCl: 1-10 g / L), and the results show that the permeability of the prepared separation membrane is >40 LMH·bar -1 , and the selectivity of CR / NaCl is >20, which is more than 2 times that of the conventional prepared membranes reported in the literature. Therefore, it is fully proved that the polymer framework material greatly improves the membrane performance, and has strong application background.

[0023] Table 1 Comparison of membrane performance with literature reported membranes

[0024] BRIEF DESCRIPTION OF DRAWINGS

[0025] Figure 1 are the surface scanning electron micrographs of the dye / salt separation membranes prepared by co-deposition, (a) (b) (c) (d) are the separation membranes prepared by adding different concentrations of polymer framework, the adding concentrations are 0 g / L, 0.25 g / L, 0.5 g / L, 1.0 g / L respectively.

[0026] Figure 2 is the mechanism diagram of the dye / salt separation membrane prepared by co-deposition. DETAILED DESCRIPTION

[0027] The application will be further described in detail below in combination with the drawings and specific examples:

[0028] The polymer framework was prepared according to the reference Mixed matrix membranes for CO2 separations by incorporating microporous polymer framework fillers with amine-rich nanochannels (DOI: 10.1016 / j.memsci.2020.118923).

[0029] 1) After hydrolysis of polyacrylonitrile ultrafiltration membrane (PAN) in sodium hydroxide aqueous solution, the hydrolyzed polyacrylonitrile ultrafiltration membrane (HPAN) was obtained by placing it in deionized water;

[0030] 2) A tris aqueous solution was prepared, and hydrochloric acid was added to adjust the pH to obtain a hydrochloric acid-tris solution;

[0031] 3) The polymer framework was added to the hydrochloric acid-tris buffer solution and ultrasonically dispersed to obtain a hydrochloric acid-tris solution of the polymer framework;

[0032] 4) The hydrochloric acid-tris solution of the polymer framework was mixed with anhydrous copper sulfate, hydrogen peroxide and dopamine in sequence and stirred, then the above mixed solution was poured on the surface of the HPAN base membrane obtained in step 1), and after static deposition, a dye / salt separation membrane based on co-deposition of dopamine and polymer framework was obtained. The surface morphology of the prepared membrane is shown in Figure 1 As the adding concentration of the polymer framework increases, the dopamine non-covalent polymer particle aggregates on the membrane surface are gradually replaced by polymer framework aggregates, and when the concentration of the polymer framework is 0.25 g / L, the membrane surface is the most continuous and uniform, and there are no obvious particle aggregates. Figure 2A schematic diagram of the construction mechanism of the polymer framework and dopamine mixed coating. The picture shows that the construction mechanism of the mixed coating mainly includes the self-polymerization of dopamine and the occurrence of covalent reaction between the polymer framework and dopamine. The amine-rich polymer framework can be covalently connected with dopamine through Michael addition / Schiff base reaction, thereby facilitating the reduction of the influence of poor interfacial compatibility on the performance of the membrane.

[0033] Example 1

[0034] 1) After hydrolyzing polyacrylonitrile ultrafiltration membrane (PAN) in 2 mol / L aqueous sodium hydroxide solution at room temperature for 20 h, the membrane was placed in deionized water for at least 30 h to obtain a hydrolyzed polyacrylonitrile ultrafiltration membrane (HPAN);

[0035] 2) A 50 mM aqueous tris solution was prepared, and 0.1 M hydrochloric acid was added to adjust the pH to 8.5 to obtain a hydrochloric acid-tris solution;

[0036] 3) 7.5 mg of dark green polymer framework was added to 30 ml of hydrochloric acid-tris buffer (50 mM, pH = 8.5) and ultrasonically dispersed for 1 h to obtain a 0.25 g / L polymer framework hydrochloric acid-tris solution;

[0037] 4) 8.3 mM anhydrous copper sulfate, 65.2 mM hydrogen peroxide (30 wt%), and 435.2 mM dopamine were sequentially added to the polymer framework hydrochloric acid-tris solution and mixed and stirred, and then the mixed solution was poured onto the surface of the HPAN-based membrane obtained in step 1), and after static deposition for 1 h, a dye / salt separation membrane was obtained, and the surface SEM image is as shown in Figure 1 (b).

[0038] Then the prepared membrane was subjected to pure water, 1 g / L salt solution (Na2SO4, NaCl), and 30 mg / L Congo red filtration experiments in sequence at 6.5 MPa. The results showed that the water permeability of the separation membrane reached 57.22 LMH·bar -1 , the salt retention rate was less than 2.61%, and the Congo red retention rate was more than 99.43%.

[0039] Example 2

[0040] 1) After hydrolyzing polyacrylonitrile ultrafiltration membrane (PAN) in 2 mol / L aqueous sodium hydroxide solution at room temperature for 20 h, the membrane was placed in deionized water for at least 30 h to obtain a hydrolyzed polyacrylonitrile ultrafiltration membrane (HPAN);

[0041] 2) A 50 mM aqueous tris solution was prepared, and 0.1 M hydrochloric acid was added to adjust the pH to 8.5 to obtain a hydrochloric acid-tris solution;

[0042] 3) 15.0 mg of dark green polymer framework was added into 30 ml of hydrochloric acid-tris buffer (50 mM, pH = 8.5) and ultrasonically dispersed for 1 h to obtain a 0.5 g / L polymer framework hydrochloric acid-tris solution;

[0043] 4) 8.3 mM of anhydrous copper sulfate, 65.2 mM of hydrogen peroxide (30 wt%), and 435.2 mM of dopamine were sequentially added to the polymer framework hydrochloric acid-tris solution and mixed and stirred, and then the mixed solution was poured onto the surface of the HPAN-based membrane obtained in step 1), and after static deposition for 1 h, a high-selectivity dye / salt separation membrane was obtained, and a surface SEM image is as shown in Figure 1 (c) Then the prepared membrane was subjected to water filtration, 1 g / L salt solution (Na2SO4, NaCl), and 30 mg / L Congo red filtration experiments in sequence at 6.5 MPa. The results showed that the water permeability of the separation membrane reached 54.35 LMH·bar -1 , the salt retention rate was less than 4.38%, and the Congo red retention rate was more than 99.59%.

[0044] Example 3

[0045] 1) After the polyacrylonitrile ultrafiltration membrane (PAN) was hydrolyzed in a 2 mol / L sodium hydroxide aqueous solution at room temperature for 20 h, it was placed in deionized water for at least 30 h to obtain a hydrolyzed polyacrylonitrile ultrafiltration membrane (HPAN);

[0046] 2) A 50 mM aqueous solution of tris (tris) was prepared, and 0.1 M hydrochloric acid was added to adjust the pH to 8.5 to obtain a hydrochloric acid-tris solution;

[0047] 3) 30 mg of dark green polymer framework was added into 30 ml of hydrochloric acid-tris buffer (50 mM, pH = 8.5) and ultrasonically dispersed for 1 h to obtain a 1 g / L polymer framework hydrochloric acid-tris solution;

[0048] 4) 8.3 mM of anhydrous copper sulfate, 65.2 mM of hydrogen peroxide (30 wt%), and 435.2 mM of dopamine were sequentially added to the polymer framework hydrochloric acid-tris solution and mixed and stirred, and then the mixed solution was poured onto the surface of the HPAN-based membrane obtained in step 1), and after static deposition for 1 h, a high-selectivity dye / salt separation membrane was obtained, and a surface SEM image is as shown in Figure 1 (d) Then the prepared membrane was subjected to water filtration, 1 g / L salt solution (Na2SO4, NaCl), and 30 mg / L Congo red filtration experiments in sequence at 6.5 MPa. The results showed that the water permeability of the separation membrane reached 52.81 LMH·bar -1 , the salt retention rate was less than 6.78%, and the Congo red retention rate was more than 99.87%.

[0049] Example 4

[0050] 1) The polyacrylonitrile ultrafiltration membrane (PAN) was hydrolyzed in 2 mol / L aqueous sodium hydroxide solution at room temperature for 20 h and then placed in deionized water for at least 30 h to obtain a hydrolyzed polyacrylonitrile ultrafiltration membrane (HPAN);

[0051] 2) A 50 mM aqueous tris solution was prepared, and 0.1 M hydrochloric acid was added to adjust the pH to 8 to obtain a hydrochloric acid-tris solution;

[0052] 3) 7.5 mg of dark green polymer framework was added to 30 ml of hydrochloric acid-tris buffer (50 mM, pH = 8) and ultrasonically dispersed for 1 h to obtain a 0.25 g / L polymer framework hydrochloric acid-tris solution;

[0053] 4) 5 mM anhydrous copper sulfate, 30 mM hydrogen peroxide (30 wt%), and 108.8 mM dopamine were sequentially added to the polymer framework hydrochloric acid-tris solution and mixed and stirred, and then the above mixed solution was poured onto the surface of the HPAN base membrane obtained in step 1), and after static deposition for 0.5 h, a high-selectivity dye / salt separation membrane was obtained, and the surface SEM image is as shown in Figure 1 (d). Then the prepared membrane was subjected to pure water, 1 g / L salt solution (Na2SO4, NaCl), and 30 mg / L Congo red filtration experiments at 6.5 MPa in sequence. The results showed that the water permeability of the separation membrane reached 65.80 LMH·bar -1 , the salt rejection rate was less than 5.20%, and the Congo red rejection rate was more than 99.00%.

[0054] Example 5

[0055] 1) The polyacrylonitrile ultrafiltration membrane (PAN) was hydrolyzed in 2 mol / L aqueous sodium hydroxide solution at room temperature for 20 h and then placed in deionized water for at least 30 h to obtain a hydrolyzed polyacrylonitrile ultrafiltration membrane (HPAN);

[0056] 2) A 50 mM aqueous tris solution was prepared, and 0.1 M hydrochloric acid was added to adjust the pH to 10 to obtain a hydrochloric acid-tris solution;

[0057] 3) 7.5 mg of dark green polymer framework was added to 30 ml of hydrochloric acid-tris buffer (50 mM, pH = 10) and ultrasonically dispersed for 1 h to obtain a 0.25 g / L polymer framework hydrochloric acid-tris solution;

[0058] 4) 20 mM of anhydrous copper sulfate, 70 mM hydrogen peroxide (30 wt%) and 652.8 mM dopamine were added to the hydrochloric acid-tris solution of the polymer framework in turn and after mixing and stirring, the above mixed solution was poured on the HPAN-based membrane surface obtained in step 1), and after static deposition for 1 h, a high-selectivity dye / salt separation membrane was obtained, and the surface SEM image is as shown in Figure 1 (d) The prepared membrane was then subjected to pure water, 1 g / L salt solution (Na2SO4, NaCl) and 30 mg / L Congo red filtration experiments in turn at 6.5 MPa. The results showed that the water permeability of the separation membrane reached 72.1 LMH·bar -1 , the salt rejection rate was less than 4.30%, and the Congo red rejection rate was more than 97.00%.

[0059] The performance of the separation membrane prepared by co-deposition of dopamine and polyethyleneimine reported in the cited document is used as the following comparative example.

[0060] Comparative Example 1

[0061] The optimal performance membrane prepared by co-deposition of dopamine and polyethyleneimine using Cu2SO4 / H2O2 as an initiator reported in the document “High flux electroneutral loose nanofiltration membranes based on rapid deposition of polydopamine / polyethyleneimine” (DOI: 10.1039 / c7ta02661g) is used as Comparative Example 1, and the data are listed in Table 2.

[0062] Comparative Example 2

[0063] The optimal performance membrane prepared by co-deposition of dopamine using FeCl3 / H2O2 as an initiator reported in the document “A rapid deposition of polydopamine coatings induced by iron(III) chloride / hydrogen peroxide for loose nanofiltration” (DOI: 10.1016 / j.jcis.2018.03.072) is used as Comparative Example 2, and the data are listed in Table 2.

[0064] Test data and conclusions

[0065] The dye / salt separation performance of the membranes prepared by co-deposition of different concentrations of polymer framework and dopamine is shown in Table 2.

[0066] Table 2 CR / Na2SO4 separation performance of membranes based on dopamine co-deposition

[0067] Water permeability / LMH*bar -1 ]]> CR / Na2SO4 selectivity Example 1 57.22 38.09 Example 2 54.35 22.74 Example 3 52.81 14.73 Example 4 65.80 19.04 Example 5 72.10 21.16 Comparative Example 1 26.20 19.50 Comparative Example 2 17.50 6.60

[0068] As can be seen from Table 2, under the CR / Na2SO4 system, with the increase of the polymer framework addition concentration, the membrane performance shows a trend of first increasing and then decreasing, and the optimal value of the polymer framework addition concentration is 0.25 g / L. Compared with the performance of the comparative example in Table 2, the membrane prepared in the present application not only has a greatly improved water permeability, but also exhibits excellent CR / Na2SO4 selectivity, and its performance is much higher than that of the membrane prepared by co-deposition of dopamine and polyethyleneimine reported in the prior art. Moreover, the membrane preparation process of the present application is simple, reproducible, and has good application prospect.

[0069] The technical solutions disclosed and presented in the present application can be realized by the technical personnel in the field through reference to the content of the present application, appropriate changes in the conditions and routes, etc. Although the methods and preparation techniques of the present application have been described through preferred examples, the relevant technical personnel can obviously make changes or recombine the methods and technical routes described in the present application without departing from the content, spirit and scope of the present application, to realize the final preparation techniques. It is particularly pointed out that all similar substitutions and changes are obvious to the technical personnel in the field, and they are all considered to be included in the spirit, scope and content of the present application.

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Claims

1. A method for preparing a dye / salt separation membrane based on co-deposition of dopamine and a polymeric framework material, characterized in that, It comprises the following steps: 1) hydrolyzing polyacrylonitrile ultrafiltration membrane in sodium hydroxide aqueous solution and then placing it in deionized water to obtain hydrolyzed polyacrylonitrile ultrafiltration membrane; 2) preparing tris aqueous solution, adding hydrochloric acid to adjust pH = 8-10 to obtain hydrochloric acid-tris solution; 3) adding polymer framework into hydrochloric acid-tris buffer solution of step 2) to ultrasonically disperse to obtain hydrochloric acid-tris solution of polymer framework; 4) pouring the mixed solution of hydrochloric acid-tris solution of polymer framework of step 3) mixed with anhydrous copper sulfate, hydrogen peroxide and dopamine after stirring into the surface of HPAN base membrane obtained in step 1), and obtaining dye / salt separation membrane after static deposition of co-deposition of dopamine and polymer framework. The polymer framework material is HMMP-1; the concentration of polymer framework in the hydrochloric acid-tris solution of polymer framework in step 3) is 0.25-1.00 g / L.

2. The method for co-deposition of a dye / salt separation membrane based on a dopamine and a polymeric framework material according to claim 1, characterized in that, The added concentration of anhydrous copper sulfate in step 4) is 5-20 mM.

3. The method for co-deposition of a dye / salt separation membrane based on a dopamine and a polymeric framework material according to claim 1, characterized in that, The added concentration of hydrogen peroxide in step 4) is 30-70 mM.

4. The method for co-deposition of a dye / salt separation membrane based on a dopamine and a polymeric framework material according to claim 1, characterized in that, The added concentration of dopamine in step 4) is 108-653 mM.

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