High-temperature-resistant reverse osmosis membrane prepared based on acyl chloride graphene oxide and ultrasonic assistance and preparation method of high-temperature-resistant reverse osmosis membrane
By using graphene oxide with acyl chloride and ultrasonic-assisted preparation technology, the problem of performance degradation of reverse osmosis membranes at high temperatures was solved, achieving efficient desalination and water flux, and improving the stability and high-temperature resistance of the membrane.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- VONTRON TECH CO LTD
- Filing Date
- 2024-11-05
- Publication Date
- 2026-05-08
AI Technical Summary
Existing reverse osmosis membranes exhibit performance degradation under high-temperature conditions, making it difficult to maintain efficient desalination and water flux in high-temperature wastewater treatment. Furthermore, the uneven dispersion of graphene oxide in the organic phase affects membrane stability.
Acyl chloride graphene oxide and ultrasonic-assisted preparation technology were used to synthesize acyl chloride graphene oxide by reacting acyl chloride with graphene oxide. Before interfacial polymerization, the organic phase solution was ultrasonically treated to make it uniformly dispersed in the organic phase to form a composite reverse osmosis membrane.
It improves the flux and desalination performance of the composite reverse osmosis membrane, especially maintaining stability under high temperature conditions. The water flux increases by 70%, the desalination rate is increased to 99.3%, and the long-term operation stability is excellent.
Smart Images
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Abstract
Description
Technical Field
[0001] This invention relates to the field of reverse osmosis composite membrane technology, specifically a high-temperature resistant reverse osmosis membrane based on acyl chloride oxygraphene and ultrasonic-assisted preparation, and its preparation method. Background Technology
[0002] In recent years, pressure-driven seawater desalination membranes using reverse osmosis technology have become a cutting-edge technology for producing fresh water from brine. However, the widespread application of this technology still faces some challenges. To ensure the long-term use of membrane elements, the temperature of the water sample to be treated usually needs to be controlled below 45℃. For high-temperature wastewater (60-95℃) from industries such as papermaking and textiles, it is necessary to cool it to an allowable temperature before membrane separation. Therefore, developing high-temperature resistant and high-performance reverse osmosis membranes is of great significance. A new concept in preparing advanced reverse osmosis membranes is to integrate nanoparticles into polyamide (PA) layers to create composite material structures. Various hydrophilic porous and non-porous nanomaterials have been used to modify reverse osmosis membranes, such as nano-silver, titanium dioxide, silica, and carbon nanotubes.
[0003] Therefore, finding a high-temperature resistant reverse osmosis membrane with excellent high-temperature resistance and long-term stability remains a key research direction.
[0004] Graphene oxide (GO) retains the advantages of graphene's structure, but with an increased number of oxygen-containing functional groups, making it more reactive than graphene. During the preparation of the PA layer, embedding a certain amount of GO during interfacial polymerization can effectively improve the membrane's water flux, stability, antifouling properties, and chlorine resistance, while the loss of desalination performance is almost negligible, making it an ideal modifying additive. Although adding GO to the aqueous phase is easy, removing excess aqueous phase with a rubber roller before interfacial polymerization can peel off some GO from the membrane surface, damaging its sheet-like structure. Conversely, when dispersed in an organic phase, GO can be distributed layer by layer from the organic phase onto the support layer, but it is difficult to disperse GO uniformly in the organic phase. Summary of the Invention
[0005] To address the aforementioned technical problems in the prior art, this invention provides a high-temperature resistant reverse osmosis membrane based on acyl chloride-oxidized graphene and ultrasonic-assisted preparation, as well as its preparation method.
[0006] A method for preparing a high-temperature resistant reverse osmosis membrane based on acyl chloride-oxidized graphene and ultrasound-assisted fabrication includes the following steps:
[0007] (1) Preparation of the base film:
[0008] Polysulfone (PSF) powder and N,N-dimethylformamide (DMF) solvent are mixed and stirred until the polysulfone dissolves in N,N-dimethylformamide and forms a transparent membrane liquid; then, the membrane liquid is cast onto a nonwoven fabric support layer to obtain a base film by a solvent-free phase inversion method.
[0009] (2) Preparation of GO-COCl:
[0010] First, triethylamine (TEA) and bis(trichloromethyl) carbonate (BTC) were dissolved in carbon tetrachloride (CCl4) to obtain TEA-CCl4 and BTC-CCl4, respectively. Graphene oxide (GO) was ultrasonically dispersed in the isoparaffin solvent Isopar G. Then, under a nitrogen atmosphere, the GO-Isopar G solution was added to BTC-CCl4, and the mixture was stirred continuously while the TEA-CCl4 solution was added dropwise to the mixture until the solution was homogeneous and stable. Finally, the mixture was refluxed at 60-80°C for 5-10 hours and then vacuum filtered. Byproducts were removed by washing with Isopar G to obtain GO-COCl.
[0011] (3) Polyamide skin structure:
[0012] m-phenylenediamine (MPD) was dissolved in deionized water as the aqueous phase, and 1,3,5-tristobenzoyl chloride (TMC) was dissolved in n-hexane as the oil phase. The two solutions were placed in two separate containers. Then, the GO-COCl prepared in (2) was dispersed in Isopar G and added to the oil phase solution. The solution was then subjected to constant temperature ultrasonic dispersion treatment. Subsequently, the nonwoven fabric with polysulfone-based membrane was immersed in the aqueous phase solution. After removing the excess liquid on the surface, the membrane was immersed in the container containing the oil phase. The resulting membrane was dried and stored at low temperature.
[0013] Further, the ratio of the polysulfone powder to N,N-dimethylformamide is (7:93)-(21:79) by mass. Preferably, the ratio of the polysulfone powder to N,N-dimethylformamide is 13:87 by mass.
[0014] Furthermore, the concentration of the TEA-CCl4 is 0.05-0.45 g / mL.
[0015] Furthermore, the concentration of the BTC-CCl4 is 0.5-1 g / mL.
[0016] Furthermore, in step (3), m-phenylenediamine (MPD) is dissolved in deionized water as the aqueous phase, with a specific concentration of 2-5 wt%.
[0017] Furthermore, 0.1-0.6 wt% of 1,3,5-tristobenzoyl chloride (TMC) is dissolved in n-hexane as the oil phase, and the GO-COCl prepared above (2) is dispersed in Isopar G at a ratio of 0.15 w / v% and then added to the oil phase solution at a ratio of 0.002 wt%.
[0018] Furthermore, the constant temperature ultrasonic dispersion treatment specifically involves a power of 300W, a frequency of 40kHz, and ultrasonic treatment for 20-30 minutes.
[0019] The high-temperature resistant reverse osmosis membrane prepared by the above method is based on acyl chloride graphene oxide and ultrasonic-assisted preparation.
[0020] Compared with the prior art, the technical effects of this invention are reflected in:
[0021] To simultaneously achieve high water permeability and high ion barrier properties, this invention synthesizes acyl chloride graphene oxide (GO-COCl) by reacting acyl chloride with graphene oxide, and adds it to the organic phase using Isopar G as a dispersant. Simultaneously, the organic phase solution is subjected to ultrasonic-assisted treatment before interfacial polymerization to ensure uniform dispersion of GO-COCl within the organic phase. Finally, a composite reverse osmosis membrane is prepared through interfacial polymerization of m-phenylenediamine (MPD) and 1,3,5-tribenzoyl chloride (TMC). This method allows GO-COCl to be added to the interior of the PA layer via crosslinking, rather than to the surface or substrate. Because the acyl chloride in GO-COCl reacts with the amine monomer to form polyamide chains, and because the organic phase solution is ultrasonically dispersed before interfacial polymerization, uniform GO-COCl sheets are sandwiched within the PA layer, which is beneficial for improving the flux, desalination performance, and stability of the composite reverse osmosis membrane.
[0022] The high-temperature resistant reverse osmosis membrane prepared by this invention has a functional layer thickness in the range of 130-180 nm. Compared with conventional commercial reverse osmosis membranes, under conditions of 25°C, sodium chloride concentration of 2000 ppm, and operating pressure of 225 psi, the water flux decreases by approximately 20%, while the desalination rate increases from 99.1% to 99.4%. When the temperature rises to 80°C, the water flux increases by 70% compared to 25°C, and the desalination rate of ordinary commercial reverse osmosis membranes decreases to 94.8%, while the high-temperature resistant reverse osmosis membrane of this invention still maintains a desalination rate of 99.3%. Even after continuous operation for 12 hours under high-temperature conditions, the water flux of the membrane remains stable, and the desalination rate remains above 99.0%, demonstrating excellent high-temperature resistance and long-term stability. Detailed Implementation
[0023] The technical solution of the present invention will be further defined below with reference to specific embodiments, but the scope of protection is not limited to the description made.
[0024] Example 1
[0025] A casting solution was prepared by mixing PSF and DMF at a mass ratio of 13:87 and then cast into a base membrane. The prepared base membrane was immersed in an aqueous solution containing 3.0 wt% MPD and 0.5 wt% sodium hydroxide for 30 seconds. After removing excess liquid from the surface, the membrane was then immersed in an Isopar G organic solvent containing 0.15 wt% TMC, n-hexane, and 0.002 wt% GO-COCl for interfacial polymerization for 20 seconds. To enhance the high-temperature resistance of the membrane, the organic solution was ultrasonically dispersed (300 W, 40 kHz) for 20 minutes before use and then placed in a vacuum environment to eliminate air bubbles. Finally, the membrane was dried in an 80°C oven for 3 minutes and stored at low temperature for later use.
[0026] Comparative Example
[0027] A casting solution was prepared by mixing PSF and DMF at a mass ratio of 13:87 and then cast into a base membrane. The prepared base membrane was immersed in an aqueous solution containing 3.0 wt% MPD and 0.5 wt% sodium hydroxide for 30 seconds. After removing excess liquid from the surface, the membrane was then immersed in an organic solvent containing 0.15 wt% TMC and n-hexane for interfacial polymerization for 20 seconds. To enhance the high-temperature resistance of the membrane, the organic solution was ultrasonically dispersed for 20 minutes before use and then placed in a vacuum environment to eliminate air bubbles. Finally, the membrane was dried in an 80°C oven for 3 minutes and stored at low temperature for later use.
[0028] The performance of the comparative membrane was compared with that of Example 1. The desalination rate and flux of both membranes were tested at 25°C and 80°C using a 2000 ppm NaCl solution and an operating pressure of 225 psi.
[0029] The test results in NaCl solution at 25℃ are shown in Table 1 below (concentrate circulation):
[0030] Table 1
[0031]
[0032] The test results in NaCl solution at 80℃ are shown in Table 2 below (concentrate circulation):
[0033] Table 2
[0034]
[0035] As shown in Tables 1 and 2, compared with the comparative example, the composite reverse osmosis membrane prepared by the present invention in Example 1 based on acyl chloride graphene oxide and ultrasonic-assisted preparation showed the following characteristics when operating in NaCl solution at 25℃: the flux decreased, the desalination rate increased from 99.1% to 99.4%, and it could operate stably for a long time; when operating in NaCl solution at 80℃, the flux increased significantly, the desalination rate of ordinary commercial reverse osmosis membrane decreased to 94.3%, while the desalination rate of high-temperature resistant reverse osmosis membrane remained at 99.3%, and after operating at high temperature for 20 hours, the membrane remained bright and stable, and the desalination rate was still above 99.3%, demonstrating excellent high-temperature resistance.
[0036] Example 2
[0037] A casting solution was prepared by mixing PSF and DMF at a mass ratio of 13:87 and then cast into a base membrane. The prepared base membrane was immersed in an aqueous solution containing 3.0 wt% MPD and 0.5 wt% sodium hydroxide for 30 seconds. After removing excess liquid from the surface, the membrane was then immersed in an Isopar G organic solvent containing 0.15 wt% TMC, n-hexane, and 0.003 wt% GO-COCl for interfacial polymerization for 20 seconds. To enhance the high-temperature resistance of the membrane, the organic solution was ultrasonically dispersed for 20 minutes before use and then placed in a vacuum environment to eliminate air bubbles. Finally, the membrane was dried in an 80°C oven for 3 minutes and stored at low temperature for later use.
[0038] Comparative Example
[0039] A casting solution was prepared by mixing PSF and DMF at a mass ratio of 13:87 and then cast into a base membrane. The prepared base membrane was immersed in an aqueous solution containing 3.0 wt% MPD and 0.5 wt% sodium hydroxide for 30 seconds. After removing excess liquid from the surface, the membrane was then immersed in an organic solvent containing 0.15 wt% TMC and n-hexane for interfacial polymerization for 20 seconds. To enhance the high-temperature resistance of the membrane, the organic solution was ultrasonically dispersed for 20 minutes before use and then placed in a vacuum environment to eliminate air bubbles. Finally, the membrane was dried in an 80°C oven for 3 minutes and stored at low temperature for later use.
[0040] The performance of the comparative membrane and the membrane from Example 2 were compared. The desalination rate and flux of both membranes were tested at 25°C and 80°C using a 2000 ppm NaCl solution and an operating pressure of 225 psi.
[0041] The test results in NaCl solution at 25℃ are shown in Table 1 below (concentrate circulation):
[0042] Table 1
[0043]
[0044] The test results in NaCl solution at 80℃ are shown in Table 2 below (concentrate circulation):
[0045] Table 2
[0046]
[0047] As shown in Tables 1 and 2, compared with the comparative example, the composite reverse osmosis membrane prepared by the present invention in Example 2 based on acyl chloride graphene oxide and ultrasonic-assisted preparation exhibits the following characteristics when operating in NaCl solution at 25°C: The flux decreased, but the desalination rate increased from 99.1% to 99.4%, and it maintained stable operation for an extended period. When operating in NaCl solution at 80°C, the flux increased, the desalination rate of the ordinary commercial reverse osmosis membrane decreased to 94.3%, while the desalination rate of the high-temperature resistant reverse osmosis membrane remained at 99.2%. Furthermore, after 20 hours of operation at high temperature, the membrane remained bright and stable, with a desalination rate still above 99.2%, demonstrating excellent high-temperature resistance. However, the overall flux decreased compared to Example 1, possibly due to excessive GO-COCl causing localized over-polymerization of the membrane.
[0048] Example 3
[0049] A casting solution was prepared by mixing PSF and DMF at a mass ratio of 13:87 and then cast into a base membrane. The prepared base membrane was immersed in an aqueous solution containing 3.0 wt% MPD and 0.5 wt% sodium hydroxide for 30 seconds. After removing excess liquid from the surface, the membrane was then immersed in an Isopar G organic solvent containing 0.15 wt% TMC, n-hexane, and 0.002 wt% GO-COCl for interfacial polymerization for 20 seconds. To enhance the high-temperature resistance of the membrane, the organic solution was ultrasonically dispersed (300 W, 40 kHz) for 20 minutes before use and then placed in a vacuum environment to eliminate air bubbles. Finally, the membrane was dried in an 80°C oven for 3 minutes and stored at low temperature for later use.
[0050] Comparative Example
[0051] A casting solution was prepared by mixing PSF and DMF at a mass ratio of 13:87 and then cast into a base membrane. The prepared base membrane was immersed in an aqueous solution containing 3.0 wt% MPD and 0.5 wt% sodium hydroxide for 30 seconds. After removing excess liquid from the surface, the membrane was then immersed in an organic solvent containing 0.15 wt% TMC and n-hexane for interfacial polymerization for 20 seconds. To enhance the high-temperature resistance of the membrane, the organic solution was ultrasonically dispersed for 20 minutes before use and then placed in a vacuum environment to eliminate air bubbles. Finally, the membrane was dried in an 80°C oven for 3 minutes and stored at low temperature for later use.
[0052] The performance of the comparative membrane and the membrane from Example 3 were compared. The desalination rate and flux of both membranes were tested at 25°C and 80°C using a 2000 ppm NaCl solution and an operating pressure of 225 psi.
[0053] The test results in NaCl solution at 25℃ are shown in Table 1 below (concentrate circulation):
[0054] Table 1
[0055]
[0056] The test results in NaCl solution at 80℃ are shown in Table 2 below (concentrate circulation):
[0057] Table 2
[0058]
[0059] As shown in Tables 1 and 2, compared with the comparative example, the composite reverse osmosis membrane prepared by the present invention in Example 3 based on acyl chloride graphene oxide and ultrasonic-assisted preparation showed the following characteristics when operating in NaCl solution at 25℃: the flux decreased, the desalination rate increased from 99.1% to 99.4%, and it could operate stably for a long time; when operating in NaCl solution at 80℃, the flux increased significantly, the desalination rate of ordinary commercial reverse osmosis membrane decreased to 94.3%, while the desalination rate of high-temperature resistant reverse osmosis membrane remained at 99.3%, and after operating at high temperature for 20 hours, the membrane remained bright and stable, and the desalination rate was still above 99.3%, demonstrating excellent high-temperature resistance.
[0060] Finally, it should be noted that the above embodiments are merely representative examples of the present invention. Obviously, the technical solution of the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the content disclosed in this invention should be considered within the scope of protection of this invention.
Claims
1. A method for preparing a high-temperature resistant reverse osmosis membrane based on acyl chloride graphene oxide and ultrasonic-assisted fabrication, characterized in that, Includes the following steps: (1) Preparation of the base film: Polysulfone (PSF) powder and N,N-dimethylformamide (DMF) solvent are mixed and stirred until the polysulfone dissolves in N,N-dimethylformamide and forms a transparent membrane liquid; then, the membrane liquid is cast onto a nonwoven fabric support layer to obtain a base film by a solvent-free phase inversion method. (2) Preparation of GO-COCl: First, triethylamine (TEA) and bis(trichloromethyl) carbonate (BTC) were dissolved in carbon tetrachloride (CCl4) to obtain TEA-CCl4 and BTC-CCl4, respectively. Graphene oxide (GO) was ultrasonically dispersed in the isoparaffin solvent Isopar G. Then, under a nitrogen atmosphere, the GO-Isopar G solution was added to BTC-CCl4, and the mixture was stirred continuously while the TEA-CCl4 solution was added dropwise to the mixture until the solution was homogeneous and stable. Finally, the mixture was refluxed at 60-80°C for 5-10 hours and then vacuum filtered. Byproducts were removed by washing with Isopar G to obtain GO-COCl. (3) Polyamide skin structure: m-phenylenediamine (MPD) was dissolved in deionized water as the aqueous phase, and 1,3,5-tribenzoyl chloride (TMC) was dissolved in n-hexane as the oil phase. The two solutions were placed in two separate containers. Then, the GO-COCl prepared in (2) was dispersed in IsoparG and added to the oil phase solution. The solution was then subjected to constant temperature ultrasonic dispersion treatment. Subsequently, the nonwoven fabric with polysulfone-based membrane was immersed in the aqueous phase solution. After removing the excess liquid on the surface, the membrane was immersed in the container containing the oil phase. The resulting membrane was dried and stored at low temperature.
2. The preparation method according to claim 1, characterized in that, The ratio of the polysulfone powder to N,N-dimethylformamide is (7:93) to (21:79) by mass.
3. The preparation method according to claim 2, characterized in that, The ratio of polysulfone powder to N,N-dimethylformamide is 13:87 by mass.
4. The preparation method according to claim 1, characterized in that, A transparent film liquid is formed in step (1).
5. The preparation method according to claim 1, characterized in that, The TEA-CCl4 has a concentration of 0.05-0.45 g / mL.
6. The preparation method according to claim 1, characterized in that, The BTC-CCl4 has a concentration of 0.5-1 g / mL.
7. The preparation method according to claim 1, characterized in that, In step (3), m-phenylenediamine (MPD) is dissolved in deionized water as the aqueous phase, with a concentration of 2-5 wt%.
8. The preparation method according to claim 1, characterized in that, The 0.1-0.6 wt% of 1,3,5-tristobenzoyl chloride (TMC) was dissolved in n-hexane as the oil phase. The GO-COCl prepared in (2) above was dispersed in Isopar G at a ratio of 0.15 w / v% and then added to the oil phase solution at a ratio of 0.002 wt%.
9. The preparation method according to claim 1, characterized in that, The constant temperature ultrasonic dispersion treatment specifically involves a power of 300W, a frequency of 40kHz, and ultrasonic treatment for 20-30 minutes.
10. A high-temperature resistant reverse osmosis membrane based on acyl chloride graphene oxide and ultrasonic-assisted preparation, prepared by the preparation method according to any one of claims 1-8.