Modified metal mesh with surface self-cleaning function for separating crude oil / seawater mixture and its preparation method

Abstract

The present invention belongs to the technical field of functional materials, and in particular to a modified metal mesh membrane with a surface self-cleaning function for separating crude oil / seawater mixtures and a preparation method thereof. A metal mesh is used as a substrate, and a photosensitizer tetracarboxylphenylporphyrin (TCPP)-doped UiO-66-NH2 metal organic framework material is grown in situ on its surface by a one-step solvent thermal method to prepare a modified metal mesh membrane. The modified metal mesh membrane has a rough surface structure and superwettability, can treat wastewater containing high-viscosity crude oil, and has an efficient photocatalytic synergistic photothermal self-cleaning effect on the high-viscosity crude oil adhered to the mesh surface and pores, and therefore has a higher flux recovery rate in recycling use. The modified metal mesh membrane shows the advantages of high oil-water separation efficiency and strong separation sustainability, and has good application prospects in the fields of oil recovery and oily wastewater treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of functional materials, and in particular relates to a modified metal mesh membrane with a surface self-cleaning function for separating crude oil / seawater mixtures and a preparation method thereof. Background Art

[0002] Frequent oil spills during offshore oil exploration, production, and transportation not only severely waste scarce petroleum resources but also cause severe damage to the marine ecosystem when large amounts of oily wastewater enter the ocean. Membrane separation technology has attracted widespread attention in the field of oily wastewater separation and treatment due to its advantages such as low cost, low energy consumption, and simple process flow. While membrane separation is relatively easy to achieve for the separation of heavy oil / water mixtures and light oil / water mixtures, the effective and sustainable separation of highly viscous crude oil / water mixtures is more challenging. While the construction of superwetting membrane materials can address the problem of oil contamination on the membrane surface to a certain extent, highly viscous crude oil inevitably clogs the membrane surface and pores during oil-water separation and long-term membrane operation, resulting in a sharp drop in membrane separation flux, thereby compromising oil-water separation efficiency and sustainability, and significantly shortening the membrane's service life. This presents a major challenge to be addressed in the practical application of membrane technology for oil-water separation. Therefore, the development of membrane materials that can efficiently separate highly viscous crude oil / water mixtures and possess surface-adherent self-cleaning properties is of great significance. Summary of the Invention

[0003] The purpose of the present invention is to provide a modified metal mesh membrane with surface self-cleaning function for separating high-viscosity crude oil / seawater mixtures and a preparation method thereof, which has practical application prospects.

[0004] The method for preparing the modified metal mesh membrane with surface self-cleaning function of the present invention is specifically carried out according to the following steps:

[0005] (1) A metal mesh substrate (including but not limited to stainless steel mesh and copper mesh) is cut into corresponding sizes as required, placed in an ethanol solution for ultrasonic cleaning, and then immersed in a tris (hydroxymethyl)aminomethane hydrochloride buffer solution (pH = 8.7) containing dopamine. The solution is heated and shaken at 50-70°C for 24 hours to allow the dopamine to uniformly self-polymerize into a polypolyamine layer on the surface of the metal mesh substrate. The polydopamine-coated metal mesh substrate is removed, cleaned with deionized water and ethanol, and then dried for later use.

[0006] Wherein, the concentration of dopamine in the buffer solution is 1-2 mg / mL.

[0007] (2) Zirconium tetrachloride and 2-aminoterephthalic acid were added to 50 mL of N,N-dimethylformamide solvent, and a certain volume of acetic acid was added, and the mixture was ultrasonically mixed to obtain solution 1. At the same time, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were ultrasonically dissolved in 10 mL of N,N-dimethylformamide solvent to obtain solution 2.

[0008] The molar ratio of zirconium tetrachloride to 2-aminoterephthalic acid is 1:1, the total molar amount of zirconium tetrachloride and 2-aminoterephthalic acid is 1-3 mmol, and the molar volume ratio of zirconium tetrachloride to acetic acid is 1 mmol:6 mL.

[0009] The mass ratio of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide is 1:1, and the concentrations of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in N,N-dimethylformamide solvent are both 0.005-0.01 mg / mL.

[0010] (3) The two solutions prepared in step (2) are mixed evenly, and then transferred to a reactor, and tetracarboxyphenylporphyrin (TCPP) is added. At the same time, the polydopamine-coated metal mesh substrate obtained in step (1) is immersed in the reactor. The reactor is heated in an oven at 120° C. for 24 hours. After the reaction is completed, the metal mesh is taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified metal mesh.

[0011] Wherein, the volume ratio of solution 1 to solution 2 is 53-59:10;

[0012] The mass molar ratio of TCPP to zirconium tetrachloride is 10-45 mg:1 mmol, and the TCPP-doped UiO-66-NH2 material in situ grown on the surface of the metal mesh accounts for 3-9% of the mass of the metal mesh substrate.

[0013] The technical effects of the present invention are:

[0014] (1) The surface of the modified metal mesh membrane prepared by the present invention is in situ grown with TCPP-doped UiO-66-NH2 material, which constructs a surface micro-nano rough structure and provides a large number of hydrophilic groups (hydroxyl and amino groups), so that the membrane exhibits super wettability. During oil-water separation, the water phase can pass through the membrane, while the oil phase is efficiently blocked on the other side of the membrane, showing higher oil-water separation efficiency and separation flux. Due to its underwater super oleophobic properties, a hydration layer can be formed on the membrane surface, which gives the membrane a certain anti-oil adhesion ability. The prepared modified metal mesh membrane has practical application prospects in treating wastewater containing highly viscous crude oil.

[0015] (2) TCPP-doped UiO-66-NH2 material is in situ grown on the surface of the modified metal mesh prepared by the present invention. TCPP is doped as a mixed organic ligand for preparing UiO-66-NH2 and is also doped by connecting with UiO-66-NH2 through an amide bond. TCPP has a conjugated macrocyclic π-electronic structure and visible light influencing ability. Its addition can not only expand the light absorption range, but also serve as an electron channel to improve the separation rate of photogenerated carriers in UiO-66-NH2. In addition, TCPP can generate singlet oxygen under light, enriching the types of active oxygen species, and has photothermal conversion ability, reducing the viscosity of crude oil adhered to the membrane surface. In view of the above advantages, the prepared modified metal mesh has excellent photocatalytic synergistic photothermal self-cleaning function for high-viscosity crude oil adhered to the surface during long-term use. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a scanning electron microscope (SEM) image of the TCPP-doped UiO-66-NH2 modified stainless steel mesh membrane prepared in Example 1 of the present invention.

[0017] Figure 2 This is a diagram of the oil-water separation device constructed as described in Example 2 of the present invention. DETAILED DESCRIPTION

[0018] The present invention is described in detail below with reference to specific embodiments.

[0019] Example 1

[0020] 1. Preparation of modified metal mesh membrane

[0021] (1) A 300-mesh stainless steel mesh was cut into a circular shape with a diameter of 2R = 6 cm, placed in an ethanol solution for ultrasonic cleaning (power 40 Hz, ultrasonic time 10 minutes), and then immersed in a tris (hydroxymethyl)aminomethane hydrochloride buffer solution (pH = 8.7) containing dopamine at a dopamine concentration of 1 mg / mL. The mesh was heated and shaken at 70°C for 24 hours to allow the dopamine to uniformly self-polymerize into a polypolyamine layer on the surface of the stainless steel mesh substrate. The polydopamine-coated stainless steel mesh substrate was removed, cleaned with deionized water and ethanol, and dried for later use.

[0022] (2) Add 0.5 mmol of zirconium tetrachloride and 0.5 mmol of 2-aminoterephthalic acid to 50 mL of N,N-dimethylformamide solvent, then add 3 mL of acetic acid and mix thoroughly by ultrasonication. Simultaneously, dissolve 0.05 mg of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.05 mg of N-hydroxysuccinimide in 10 mL of N,N-dimethylformamide solvent by ultrasonication.

[0023] (3) The two solutions prepared in step (2) were mixed evenly, and then transferred to a reactor, and 15 mg of tetracarboxyphenylporphyrin (TCPP) was added. At the same time, the polydopamine-coated stainless steel substrate obtained in step (1) was immersed in the reactor. The reactor was heated in an oven at 120° C. for 24 hours. After the reaction was completed, the stainless steel mesh was taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified stainless steel mesh. The TCPP-doped UiO-66-NH2 material in situ grown on the surface of the stainless steel mesh accounted for 3% of the mass of the metal mesh substrate.

[0024] 2. Separation process of high-viscosity crude oil / seawater mixture and self-cleaning process of membrane surface

[0025] The prepared modified stainless steel mesh was first moistened with water and then placed between the constructed oil-water separation devices. A high-viscosity crude oil / seawater mixture (the crude oil viscosity was 2×10 5 mPa s), the separation process is completed only by gravity. The flux (F) is calculated as follows: F = V / (S×Δt), where V (L), S (m 2 ), Δt(h) are the filtration volume, membrane effective filtration area, and separation time, respectively. The separation efficiency is calculated as follows: η = m1 / m0 × 100%, where m1 and m0 are the mass of seawater before and after separation, respectively. The calculated flux is 49673 L m -2 h -1 , the separation efficiency is 99.5%.

[0026] The initial pure water flux of the modified stainless steel mesh membrane for separating highly viscous crude oil / seawater mixture was measured. The crude oil contaminated mesh membrane was then preliminarily cleaned with deionized water. The cleaned modified stainless steel mesh membrane was placed under simulated sunlight to initiate the photocatalytic reaction (0.3 W·cm -2 Xenon lamp irradiation was used to photothermally degrade the crude oil remaining on the membrane surface and in its pore structure. The pure water flux was measured every two minutes, and after 12 minutes, the flux recovery rate reached 100%, completing the membrane surface self-cleaning process.

[0027] The oil-water separation device constructed in this embodiment is shown in FIG. Figure 2 .

[0028] Example 2

[0029] 1. Preparation of modified metal mesh membrane

[0030] (1) A 300-mesh copper mesh was cut into a circular shape with a diameter of 2R = 6 cm, placed in an ethanol solution for ultrasonic cleaning, and then immersed in a tris (hydroxymethyl)aminomethane hydrochloride buffer solution (pH = 8.7) containing dopamine at a dopamine concentration of 2 mg / mL. The dopamine was heated at 70°C and shaken for 24 hours to allow the dopamine to uniformly self-polymerize into a polypolyamine layer on the surface of the copper mesh substrate. The polydopamine-coated copper mesh substrate was removed, cleaned with deionized water and ethanol, and dried for later use.

[0031] (2) Add 0.5 mmol of zirconium tetrachloride and 0.5 mmol of 2-aminoterephthalic acid to 50 mL of N,N-dimethylformamide solvent, then add 3 mL of acetic acid and mix thoroughly by ultrasonication. Simultaneously, dissolve 0.05 mg of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.05 mg of N-hydroxysuccinimide in 10 mL of N,N-dimethylformamide solvent by ultrasonication.

[0032] (3) The two solutions prepared in step (2) were mixed evenly, and then transferred to a reactor, and 15 mg of tetracarboxyphenylporphyrin (TCPP) was added. At the same time, the polydopamine-coated copper mesh substrate obtained in step (1) was immersed in the reactor. The reactor was heated in an oven at 120° C. for 24 hours. After the reaction was completed, the copper mesh membrane was taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified copper mesh membrane. The TCPP-doped UiO-66-NH2 material in situ generated on the copper mesh surface accounted for 3.2% of the mass of the metal mesh substrate.

[0033] 2. Separation process of high-viscosity crude oil / seawater mixture and self-cleaning process of membrane surface

[0034] The prepared modified stainless steel mesh was first moistened with water and then placed between the constructed oil-water separation devices. A high-viscosity crude oil / seawater mixture (the crude oil viscosity was 2×10 5 mPa s), the separation process is completed only by gravity. The calculation of flux (F) and separation efficiency is the same as in Example 1. The calculated flux is 50290 L m -2 h -1 , the separation efficiency is 99.5%.

[0035] The flux recovery test process was the same as in Example 1. After 14 minutes, the flux recovery rate was 100%, and the self-cleaning process of the membrane surface was completed.

[0036] Example 3

[0037] 1. Preparation of modified metal mesh membrane

[0038] (1) A 300-mesh stainless steel mesh was cut into a circular shape with a diameter of 2R = 6 cm, placed in an ethanol solution for ultrasonic cleaning, and then immersed in a tris (hydroxymethyl)aminomethane hydrochloride buffer solution (pH = 8.7) containing dopamine at a dopamine concentration of 2 mg / mL. The mesh was heated and shaken at 60°C for 24 hours to allow the dopamine to uniformly self-polymerize into a polypolyamine layer on the surface of the stainless steel mesh substrate. The polydopamine-coated stainless steel mesh substrate was removed, cleaned with deionized water and ethanol, and dried for later use.

[0039] (2) Add 1 mmol of zirconium tetrachloride and 1 mmol of 2-aminoterephthalic acid to 50 mL of N,N-dimethylformamide solvent, then add 6 mL of acetic acid and mix thoroughly by ultrasonication. Simultaneously, dissolve 0.05 mg of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.05 mg of N-hydroxysuccinimide in 10 mL of N,N-dimethylformamide solvent by ultrasonication.

[0040] (3) The two solutions prepared in step (2) were mixed evenly, and then transferred to a reactor, and 30 mg of tetracarboxyphenylporphyrin (TCPP) was added. At the same time, the polydopamine-coated stainless steel substrate obtained in step (1) was immersed in the reactor. The reactor was heated in an oven at 120° C. for 24 hours. After the reaction was completed, the stainless steel mesh was taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified stainless steel mesh. The TCPP-doped UiO-66-NH2 material in situ grown on the surface of the stainless steel mesh accounted for 9% of the mass of the metal mesh substrate.

[0041] The scanning electron microscope (SEM) image of the TCPP-doped UiO-66-NH2 modified stainless steel mesh membrane prepared in this embodiment is shown in FIG. Figure 1 .

[0042] 2. Separation process of high-viscosity crude oil / seawater mixture and self-cleaning process of membrane surface

[0043] The prepared modified stainless steel mesh was first moistened with water and then placed between the constructed oil-water separation devices. A high-viscosity crude oil / seawater mixture (the crude oil viscosity was 2×10 5 mPa s), the separation process is completed only by gravity. The calculation of flux (F) and separation efficiency is the same as in Example 1. The calculated flux is 59740 L m -2 h -1 , the separation efficiency is 99.7%.

[0044] The flux recovery test process was the same as in Example 1. After 8 minutes, the flux recovery rate was 100%, and the self-cleaning process of the membrane surface was completed.

[0045] Example 4

[0046] 1. Preparation of modified metal mesh membrane

[0047] Step (1) and step (2) are the same as in Example 3.

[0048] (3) The two solutions prepared in step (2) were mixed evenly, and then transferred to a reactor, and 45 mg of tetracarboxyphenylporphyrin (TCPP) was added. At the same time, the polydopamine-coated stainless steel substrate obtained in step (1) was immersed in the reactor. The reactor was heated in an oven at 120° C. for 24 hours. After the reaction was completed, the stainless steel mesh was taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified stainless steel mesh. The TCPP-doped UiO-66-NH2 material in situ grown on the surface of the stainless steel mesh accounted for 6.8% of the mass of the metal mesh substrate.

[0049] 2. Separation process of high-viscosity crude oil / seawater mixture and self-cleaning process of membrane surface

[0050] The prepared modified stainless steel mesh was first moistened with water and then placed between the constructed oil-water separation devices. A high-viscosity crude oil / seawater mixture (the crude oil viscosity was 2×10 5 mPa s), the separation process is completed only by gravity. The calculation of flux (F) and separation efficiency is the same as in Example 1. The calculated flux is 53468 L m -2 h -1 , the separation efficiency is 99.5%.

[0051] The flux recovery test process was the same as in Example 1. After 11 minutes, the flux recovery rate was 100%, and the self-cleaning process of the membrane surface was completed.

[0052] Example 5

[0053] 1. Preparation of modified metal mesh membrane

[0054] Step (1) and step (2) are the same as in Example 3.

[0055] (3) The two solutions prepared in step (2) were mixed evenly, and then transferred to a reactor, and 15 mg of tetracarboxyphenylporphyrin (TCPP) was added. At the same time, the polydopamine-coated stainless steel substrate obtained in step (1) was immersed in the reactor. The reactor was heated in an oven at 120° C. for 24 hours. After the reaction was completed, the stainless steel mesh was taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified stainless steel mesh. The TCPP-doped UiO-66-NH2 material in situ grown on the surface of the stainless steel mesh accounted for 5.5% of the mass of the metal mesh substrate.

[0056] 2. Separation process of high-viscosity crude oil / seawater mixture and self-cleaning process of membrane surface

[0057] The prepared modified stainless steel mesh was first moistened with water and then placed between the constructed oil-water separation devices. A high-viscosity crude oil / seawater mixture (the crude oil viscosity was 2×10 5 mPa s), the separation process is completed only by gravity. The calculation of flux (F) and separation efficiency is the same as in Example 1. The calculated flux is 55670 L m -2 h -1 , the separation efficiency is 99.6%.

[0058] The flux recovery test process was the same as in Example 1. After 13 minutes, the flux recovery rate was 100%, and the self-cleaning process of the membrane surface was completed.

[0059] Example 6

[0060] 1. Preparation of modified metal mesh membrane

[0061] (1) A 300-mesh copper mesh was cut into a circular shape with a diameter of 2R = 6 cm, placed in an ethanol solution for ultrasonic cleaning, and then immersed in a tris (hydroxymethyl)aminomethane hydrochloride buffer solution (pH = 8.7) containing dopamine at a dopamine concentration of 2 mg / mL. The dopamine was heated at 50°C and shaken for 24 hours to allow the dopamine to uniformly self-polymerize into a polypolyamine layer on the surface of the copper mesh substrate. The polydopamine-coated copper mesh substrate was removed, cleaned with deionized water and ethanol, and dried for later use.

[0062] (2) Add 1.5 mmol of zirconium tetrachloride and 1.5 mmol of 2-aminoterephthalic acid to 50 mL of N,N-dimethylformamide solvent, then add 9 mL of acetic acid and mix thoroughly by ultrasonication. Simultaneously, dissolve 0.1 mg of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.1 mg of N-hydroxysuccinimide in 10 mL of N,N-dimethylformamide solvent by ultrasonication.

[0063] (3) The two solutions prepared in step (2) were mixed evenly, and then transferred to a reactor, and 45 mg of tetracarboxyphenylporphyrin (TCPP) was added. At the same time, the polydopamine-coated copper mesh substrate obtained in step (1) was immersed in the reactor. The reactor was heated in an oven at 120° C. for 24 hours. After the reaction was completed, the copper mesh membrane was taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified copper mesh membrane. The TCPP-doped UiO-66-NH2 material in situ generated on the copper mesh surface accounted for 8.7% of the mass of the metal mesh substrate.

[0064] 2. Separation process of high-viscosity crude oil / seawater mixture and self-cleaning process of membrane surface

[0065] The prepared modified copper mesh membrane was first moistened with water and then placed between the constructed oil-water separation devices. A high-viscosity crude oil / seawater mixture (the crude oil viscosity was 2×10 5 mPa s), the separation process is completed only by gravity. The calculation of flux (F) and separation efficiency is the same as in Example 1. The calculated flux is 54540 L m -2 h -1 , the separation efficiency is 99.7%.

[0066] The flux recovery test process was the same as in Example 1. After 10 minutes, the flux recovery rate was 100%, and the self-cleaning process of the membrane surface was completed.

[0067] Example 7

[0068] 1. Preparation of modified metal mesh membrane

[0069] (1) A 300-mesh copper mesh was cut into a circular shape with a diameter of 2R = 6 cm, placed in an ethanol solution for ultrasonic cleaning, and then immersed in a tris (hydroxymethyl)aminomethane hydrochloride buffer solution (pH = 8.7) containing dopamine at a dopamine concentration of 1.8 mg / mL. The mesh was heated and shaken at 60°C for 24 hours to allow the dopamine to uniformly self-polymerize into a poly(polyamine) layer on the surface of the copper mesh substrate. The polydopamine-coated copper mesh substrate was removed, cleaned with deionized water and ethanol, and dried for later use.

[0070] (2) Add 1.2 mmol of zirconium tetrachloride and 1.2 mmol of 2-aminoterephthalic acid to 50 mL of N,N-dimethylformamide solvent, then add 7.2 mL of acetic acid and mix thoroughly by ultrasonication. Simultaneously, dissolve 0.06 mg of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.06 mg of N-hydroxysuccinimide in 10 mL of N,N-dimethylformamide solvent by ultrasonication.

[0071] (3) The two solutions prepared in step (2) were mixed evenly, and then transferred to a reactor, and 18 mg of tetracarboxyphenylporphyrin (TCPP) was added. At the same time, the polydopamine-coated copper mesh substrate obtained in step (1) was immersed in the reactor. The reactor was heated in an oven at 120° C. for 24 hours. After the reaction was completed, the copper mesh membrane was taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified copper mesh membrane. The TCPP-doped UiO-66-NH2 material in situ grown on the surface of the copper mesh accounted for 7% of the mass of the metal mesh substrate.

[0072] 2. Separation process of high-viscosity crude oil / seawater mixture and self-cleaning process of membrane surface

[0073] The prepared modified copper mesh membrane was first moistened with water and then placed between the constructed oil-water separation devices. A high-viscosity crude oil / seawater mixture (the crude oil viscosity was 2×10 5 mPa s), the separation process is completed only by gravity. The calculation of flux (F) and separation efficiency is the same as in Example 1. The calculated flux is 47254 L m -2 h -1 , the separation efficiency is 99.6%.

[0074] The flux recovery test process was the same as in Example 1. After 6 minutes, the flux recovery rate was 100%, and the self-cleaning process of the membrane surface was completed.

[0075] Example 8

[0076] 1. Preparation of modified metal mesh membrane

[0077] (1) A 300-mesh copper mesh was cut into a circular shape with a diameter of 2R = 6 cm, placed in an ethanol solution for ultrasonic cleaning, and then immersed in a tris (hydroxymethyl)aminomethane hydrochloride buffer solution (pH = 8.7) containing dopamine at a dopamine concentration of 1.8 mg / mL. The mesh was heated and shaken at 60°C for 24 hours to allow the dopamine to uniformly self-polymerize into a poly(polyamine) layer on the surface of the copper mesh substrate. The polydopamine-coated copper mesh substrate was removed, cleaned with deionized water and ethanol, and dried for later use.

[0078] (2) Add 1.2 mmol of zirconium tetrachloride and 1.2 mmol of 2-aminoterephthalic acid to 50 mL of N,N-dimethylformamide solvent, then add 7.2 mL of acetic acid and mix thoroughly by ultrasonication. Simultaneously, dissolve 0.1 mg of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.1 mg of N-hydroxysuccinimide in 10 mL of N,N-dimethylformamide solvent by ultrasonication.

[0079] (3) The two solutions prepared in step (2) were mixed evenly, and then transferred to a reactor, and 15 mg of tetracarboxyphenylporphyrin (TCPP) was added. At the same time, the polydopamine-coated stainless steel substrate obtained in step (1) was immersed in the reactor. The reactor was heated in an oven at 120° C. for 24 hours. After the reaction was completed, the stainless steel mesh was taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified stainless steel mesh. The TCPP-doped UiO-66-NH2 material in situ grown on the surface of the stainless steel mesh accounted for 7.4% of the mass of the metal mesh substrate.

[0080] 2. Separation process of high-viscosity crude oil / seawater mixture and self-cleaning process of membrane surface

[0081] The prepared modified stainless steel mesh was first moistened with water and then placed between the constructed oil-water separation devices. A high-viscosity crude oil / seawater mixture (the crude oil viscosity was 2×10 5 mPa s), the separation process is completed only by gravity. The calculation of flux (F) and separation efficiency is the same as in Example 1. The calculated flux is 55293 L m -2 h -1 , the separation efficiency is 99.5%.

[0082] The flux recovery test process was the same as in Example 1. After 13 minutes, the flux recovery rate was 100%, and the self-cleaning process of the membrane surface was completed.

[0083] Example 9

[0084] 1. Preparation of modified metal mesh membrane

[0085] (1) A 300-mesh stainless steel mesh was cut into a circular shape with a diameter of 2R = 6 cm, placed in an ethanol solution for ultrasonic cleaning, and then immersed in a tris (hydroxymethyl)aminomethane hydrochloride buffer solution (pH = 8.7) containing dopamine at a dopamine concentration of 1.5 mg / mL. The mesh was heated and shaken at 50°C for 24 hours to allow the dopamine to uniformly self-polymerize into a polypolyamine layer on the surface of the stainless steel mesh substrate. The polydopamine-coated stainless steel mesh substrate was removed, cleaned with deionized water and ethanol, and dried for later use.

[0086] (2) Add 1.5 mmol of zirconium tetrachloride and 1.5 mmol of 2-aminoterephthalic acid to 50 mL of N,N-dimethylformamide solvent, then add 9 mL of acetic acid and mix thoroughly by ultrasonication. Simultaneously, dissolve 0.1 mg of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and 0.1 mg of N-hydroxysuccinimide in 10 mL of N,N-dimethylformamide solvent by ultrasonication.

[0087] (3) The two solutions prepared in step (2) were mixed evenly, and then transferred to a reactor, and 45 mg of tetracarboxyphenylporphyrin (TCPP) was added. At the same time, the polydopamine-coated stainless steel substrate obtained in step (1) was immersed in the reactor. The reactor was heated in an oven at 120° C. for 24 hours. After the reaction was completed, the metal mesh was taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified stainless steel mesh. The TCPP-doped UiO-66-NH2 material in situ grown on the surface of the stainless steel mesh accounted for 9% of the mass of the metal mesh substrate.

[0088] 2. Separation process of high-viscosity crude oil / seawater mixture and self-cleaning process of membrane surface

[0089] The prepared modified stainless steel mesh was first moistened with water and then placed between the constructed oil-water separation devices. A high-viscosity crude oil / seawater mixture (the crude oil viscosity was 2×10 5 mPa s), the separation process is completed only by gravity. The calculation of flux (F) and separation efficiency is the same as in Example 1. The calculated flux is 56783 L m -2 h -1 , the separation efficiency is 99.4%.

[0090] The flux recovery test process was the same as in Example 1. After 8 minutes, the flux recovery rate was 100%, and the self-cleaning process of the membrane surface was completed.

[0091] Comparative Example 1

[0092] 1. Preparation of modified metal mesh membrane

[0093] Step (1) is the same as in Example 2.

[0094] (2) Add 0.5 mmol of zirconium tetrachloride and 0.5 mmol of 2-aminoterephthalic acid to 50 mL of N,N-dimethylformamide solvent, then add 3 mL of acetic acid and mix thoroughly by ultrasonication.

[0095] (3) The solution prepared in step (2) was transferred to a reactor, and 15 mg of tetracarboxyphenylporphyrin (TCPP) was added. At the same time, the polydopamine-coated stainless steel substrate obtained in step (1) was immersed in the reactor. The reactor was heated in an oven at 120° C. for 24 hours. After the reaction was completed, the stainless steel mesh was taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified stainless steel mesh. The TCPP-doped UiO-66-NH2 material in situ grown on the surface of the stainless steel mesh accounted for 4.7% of the mass of the metal mesh substrate.

[0096] 2. Separation process of high-viscosity crude oil / seawater mixture and self-cleaning process of membrane surface

[0097] The prepared modified stainless steel mesh was first moistened with water and then placed between the constructed oil-water separation devices. A high-viscosity crude oil / seawater mixture (the crude oil viscosity was 2×10 5 mPa s), the separation process is completed only by gravity. The calculation of flux (F) and separation efficiency is the same as in Example 1. The calculated flux is 48762 L m -2 h -1 , the separation efficiency is 99.2%.

[0098] The flux recovery test process was the same as in Example 1. After 14 minutes, the flux recovery rate was 100%, and the self-cleaning process of the membrane surface was completed.

[0099] Comparative Example 2

[0100] 1. Preparation of modified metal mesh membrane

[0101] Step (1) and step (2) are the same as in Example 1.

[0102] (3) The two solutions prepared in step (2) were mixed evenly and then transferred to a reactor. At the same time, the polydopamine-coated stainless steel substrate obtained in step (1) was immersed in the reactor. The reactor was heated in an oven at 120° C. for 24 hours. After the reaction was completed, the stainless steel mesh was taken out, washed with ethanol and dried to obtain a UiO-66-NH2-modified stainless steel mesh. The UiO-66-NH2 material in situ grown on the surface of the stainless steel mesh accounted for 4.8% of the mass of the metal mesh substrate.

[0103] 2. Separation process of high-viscosity crude oil / seawater mixture and self-cleaning process of membrane surface

[0104] The prepared modified stainless steel mesh was first moistened with water and then placed between the constructed oil-water separation devices. A high-viscosity crude oil / seawater mixture (the crude oil viscosity was 2×10 5 mPa s), the separation process is completed only by gravity. The calculation of flux (F) and separation efficiency is the same as in Example 1. The calculated flux is 36723 L m -2 h -1 , the separation efficiency is 92.4%.

[0105] The flux recovery test process was the same as in Example 1, and the flux did not recover after 12 minutes.

Claims

1. A method for preparing a modified metal mesh membrane with surface self-cleaning function, characterized in that: The preparation method comprises the following steps: (1) After cutting the metal mesh substrate as needed, place it in an ethanol solution for ultrasonic cleaning, then immerse it in a tris(hydroxymethyl)aminomethane hydrochloride buffer solution with a pH of 8.7 containing dopamine, and heat and shake it at a temperature of 50-70°C for 24 hours to allow dopamine to uniformly self-polymerize into a polydopamine layer on the surface of the metal mesh substrate; remove the polydopamine-coated metal mesh substrate, clean it with deionized water and ethanol, and then dry it for use; (2) Zirconium tetrachloride and 2-aminoterephthalic acid were added to N,N-dimethylformamide solvent, and acetic acid was added, and the mixture was ultrasonically mixed to obtain solution 1; 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide were ultrasonically dissolved in N,N-dimethylformamide solvent to obtain solution 2; (3) The two solutions prepared in step (2) were mixed evenly, and then transferred to a reactor, and tetracarboxyphenylporphyrin TCPP was added. The polydopamine-coated metal mesh substrate obtained in step (1) was then immersed in the reactor. The reactor was heated in an oven at 120°C for 24 hours. After the reaction was completed, the metal mesh was taken out, washed with ethanol and dried to obtain a TCPP-doped UiO-66-NH2-modified metal mesh.

2. The method for preparing a modified metal mesh membrane with a surface self-cleaning function according to claim 1, characterized in that: In step (1), the metal mesh substrate includes a stainless steel mesh and a copper mesh; the concentration of dopamine in the buffer solution is 1-2 mg / mL.

3. The method for preparing a modified metal mesh membrane with a surface self-cleaning function according to claim 1, characterized in that: In step (2), the molar ratio of zirconium tetrachloride to 2-aminoterephthalic acid is 1:1, the total molar amount of zirconium tetrachloride and 2-aminoterephthalic acid is 1-3 mmol, and the molar volume ratio of zirconium tetrachloride to acetic acid is 1 mmol: 6 mL.

4. The method for preparing a modified metal mesh membrane with a surface self-cleaning function according to claim 1, wherein: In step (2), the mass ratio of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride to N-hydroxysuccinimide is 1:1, and the concentrations of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride and N-hydroxysuccinimide in N,N-dimethylformamide are both 0.005-0.01 mg / mL.

5. The method for preparing a modified metal mesh membrane with a surface self-cleaning function according to claim 1, characterized in that: In step (3), the volume ratio of solution 1 to solution 2 is 53-59:10; The mass molar ratio of TCPP to zirconium tetrachloride is 10-45 mg:1 mmol, and the TCPP-doped UiO-66-NH2 material in situ generated on the metal mesh surface accounts for 3-9% of the mass of the metal mesh substrate.

6. A modified metal mesh membrane with surface self-cleaning function prepared by the method according to any one of claims 1 to 5, characterized in that: TCPP in the modified metal mesh membrane is doped not only as a mixed organic ligand for preparing UiO-66-NH2, but also connected with UiO-66-NH2 through an amide bond for doping.

7. An application of a modified metal mesh membrane with surface self-cleaning function prepared by the method according to any one of claims 1 to 5, characterized in that: The modified metal mesh membrane is used for separating high-viscosity crude oil / seawater mixture.

8. The use of the modified metal mesh membrane with surface self-cleaning function according to claim 7, characterized in that: The volume ratio of crude oil to seawater in the high-viscosity crude oil / seawater mixture is 1:10-1:5.

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