A continuous preparation method of reverse osmosis membrane based on micro-evaporation balance regulation

Abstract

The application discloses a kind of based on micro-evaporation balance regulation and control reverse osmosis membrane continuous preparation method.This method is in continuous production line, porous support film is coated with the aqueous solution containing m-phenylenediamine and after being blown by air knife and removing excess droplets, not immediately interface polymerization is carried out, but it is continuously introduced into micro-evaporation balance cabin for processing, cabin temperature is controlled to 25~30 ℃, relative humidity is controlled to 45%~55% RH, residence time is 8~15 s, and parallel steady-state parallel airflow with 0.5~1.2 m / s is inputted.Subsequently, the base film is immersed into organic phase solution containing trimesoyl chloride to occur interface polymerization.The application utilizes specific temperature and humidity and steady-state parallel airflow narrow critical window, provides surface tension leveling time for aqueous film and deep monomer capillary upwelling power, and completely eliminates air knife corrugation defect.

Description

Technical Field

[0001] This invention relates to the field of polymer separation membrane manufacturing technology, and more specifically, to a continuous preparation method for reverse osmosis membranes based on micro-evaporation equilibrium control. Background Technology

[0002] Polyamide reverse osmosis membranes, as a highly efficient membrane separation technology, play a crucial role in seawater desalination, brackish water desalination, and ultrapure water production. Currently, the most mature and widely used method for industrially preparing polyamide reverse osmosis membranes is interfacial polymerization. This method typically uses a porous polysulfone membrane as the substrate, which is first contacted with an aqueous solution containing m-phenylenediamine, followed by an organic solution containing trimesoyl chloride. The two monomers undergo an extremely rapid condensation reaction at the water-oil interface, thereby generating an ultrathin and dense polyamide separation layer on the substrate surface that serves as the core for separation.

[0003] In existing industrial continuous production lines for reverse osmosis membranes, to achieve large-scale roll-to-roll manufacturing, excess surface moisture must be physically removed from the base membrane after coating with an aqueous solution. Chinese patent CN104707767B discloses a reverse osmosis membrane manufacturing method and equipment that uses interfacial polymerization to form the membrane and employs an air knife to dry excess liquid from the substrate surface before it enters the organic phase contact reaction. This process of using a high-pressure air knife for surface dehydration is currently standard practice in industrial production lines, its purpose being to prevent excessively thick water films from causing uncontrolled interfacial polymerization reactions and excessive consumption of organic phase solvents.

[0004] However, the aforementioned traditional dewatering processes reveal insurmountable physical defects in actual continuous production. When high-pressure air knives sweep the liquid surface, they generate strong shear forces on the liquid film at the micron level, leaving fine ripples and stress concentration points on the base membrane surface. Due to the high fiber feeding speed in industrial production lines, the membrane tape typically enters the organic phase tank directly within a very short time after being processed by the air knife. Although Chinese patent CN108079806A mentions that the residence time during the coating process has a significant impact on the separation performance of the semi-permeable membrane, it does not disclose how to precisely intervene in this brief physical process from after the air knife treatment to before entering the organic phase. This results in the microscopic ripples blown out by the air knife not having time to level out, and are subsequently permanently frozen inside the polyamide layer during the rapidly occurring interfacial polymerization, causing uneven membrane thickness and a persistently high local salt leakage defect rate.

[0005] Besides surface ripple defects, traditional air knife processes and excessively short air residence times also hinder the effective upflow of reactive monomers deep within the membrane pores. While high-pressure air knives remove the surface m-phenylenediamine aqueous solution, the solution inside the membrane pores cannot be replenished to the gas-liquid interface in time without sufficient capillary pull. To improve the uniformity of aqueous monomer distribution, existing technologies typically add various surfactants or polymeric thickeners to the aqueous solution. However, these added chemicals not only increase production costs but also easily remain in the generated polyamide network, causing steric hindrance and blocking water channels. This leads to a significant decrease in membrane water flux, making it difficult to overcome the trade-off between permeability and selectivity.

[0006] In summary, current continuous fabrication technologies for polyamide reverse osmosis membranes suffer from significant process blind spots in the transition between aqueous phase coating and interfacial polymerization. Existing methods rely excessively on brute-force air knife dewatering or the addition of complex chemical additives, failing to address the issues of microscopic membrane fluctuations and uneven monomer concentrations in the deep layers from the perspective of pure fluid dynamics and micro-thermodynamic equilibrium. Therefore, there is an urgent need in this field to develop a novel continuous fabrication process that, without introducing additional chemical additives, can completely eliminate air knife ripple defects and induce reasonable enrichment of deep monomers through precise physical control of the coated aqueous phase membrane, thereby stably fabricating polyamide reverse osmosis membranes with high desalination rates, high water flux, and extremely uniform structure. Summary of the Invention

[0007] The main technical problem to be solved by this invention is that in existing industrial continuous production lines for reverse osmosis membranes, micro-ripple defects are easily left on the membrane surface after the aqueous phase is coated and water is removed by air knife. Furthermore, the aqueous phase monomers in the deep pores do not have time to replenish the surface before entering the organic phase to react, resulting in uneven thickness of the polyamide separation layer formed by interfacial polymerization, high local salt leakage defect rate, and limited water flux.

[0008] To address the aforementioned technical problems, this invention provides a continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control, comprising the following steps: Step 1: The porous support membrane is continuously immersed in an aqueous solution containing m-phenylenediamine for coating. Then, an air knife is used to blow away excess droplets on the surface of the porous support membrane to obtain a base membrane with an aqueous liquid film attached to its surface. Step 2: The base film treated by the air knife is continuously introduced into the micro-evaporation balancing chamber for steady-state parallel airflow micro-evaporation balancing treatment; wherein, the temperature in the micro-evaporation balancing chamber is constantly controlled at 25~30 ℃, the relative humidity is constantly controlled at 45%~55% RH, the residence time of the base film in the micro-evaporation balancing chamber is 8~15 s, and a steady-state parallel airflow consistent with the direction of travel of the base film is introduced into the micro-evaporation balancing chamber, and the wind speed of the steady-state parallel airflow is controlled at 0.5~1.2 m / s; Step 3: The base film, which has undergone the steady-state parallel airflow micro-evaporation equilibrium treatment, is continuously immersed in an organic phase solution containing trimesoyl chloride to carry out an interfacial polymerization contact reaction, thereby generating a polyamide separation layer on the surface of the base film. Step 4: The reacted base membrane is drawn out and subjected to heat treatment and water washing in sequence, and finally wound up to obtain the reverse osmosis membrane.

[0009] In a preferred embodiment, in step one, the aqueous solution consists of deionized water and m-phenylenediamine, without any additional additives, wherein the mass fraction of m-phenylenediamine in the aqueous solution is 1.5~2.5 wt%. This invention achieves uniform monomer distribution purely through process control, thereby completely avoiding membrane pore blockage caused by residual surfactants or macromolecular thickeners.

[0010] In a preferred embodiment, in step one, the porous support membrane is a porous polysulfone support membrane.

[0011] In a preferred embodiment, in step one, the working pressure of the air knife is controlled to be 0.05~0.15 MPa.

[0012] In a preferred embodiment, in step two, the micro-evaporation balancing chamber is a sealed chamber with inlet and outlet slits for the membrane strip at both ends. The temperature and relative humidity of the steady-state parallel airflow are consistent with the constant temperature and constant relative humidity inside the micro-evaporation balancing chamber, respectively. This ensures the absolute stability of the micro-evaporation environment on the liquid film surface.

[0013] In a preferred embodiment, in step three, the organic phase solution is composed of an isoparaffin solvent and trimesoyl chloride, wherein the mass fraction of trimesoyl chloride in the organic phase solution is 0.05~0.15 wt%.

[0014] In a preferred embodiment, in step three, the contact reaction time of the base film immersed in the organic phase solution containing trimesoyl chloride is controlled to be 10-20 s; and the temperature of the organic phase solution containing trimesoyl chloride is constantly controlled to be 20-25 ℃.

[0015] In a preferred embodiment, in step four, the heat treatment is carried out continuously in a hot air oven, the temperature of the heat treatment is controlled at 85~100 ℃, and the time of the heat treatment is controlled at 2~5 min.

[0016] In a preferred embodiment, in step four, the water washing process involves continuously rinsing the base membrane with deionized water at a temperature of 40-60°C.

[0017] Compared with the prior art, the present invention has the following beneficial effects: First, it completely eliminates the "air knife ripple" defect, significantly improving the membrane roll yield. This invention breaks with the traditional process of "directly immersing the membrane in the organic phase after air knife dewatering," cleverly setting a residence zone under specific temperature, humidity, and a light breeze environment between the two. During this period, through the physical leveling effect of surface tension, the microscopic ripples generated by the air knife are completely smoothed, preventing the ripple defects from freezing during rapid interfacial polymerization. Macroscopically, this results in a significant reduction in the coefficient of variation (CV) of the water flux of the entire large-area reverse osmosis membrane roll, almost complete elimination of localized salt leakage points, and extremely stable and uniform product quality.

[0018] Secondly, the invention precisely induces the capillary upwelling of deep monomers, resulting in a significant increase in water flux. The invention defines a critical window of "45%~55% RH relative humidity" and "8~15 s residence time." Within this window, minute and controlled micro-evaporation occurs on the liquid membrane surface. The slight reduction in surface moisture triggers capillary suction, precisely drawing the m-phenylenediamine solution deep within the membrane pores to the surface, forming a nanoscale high-concentration monomer layer at the gas-liquid interface. This allows the subsequent interfacial polymerization reaction to close rapidly and form an ultrathin desalination layer, effectively blocking ineffective deep diffusion of monomers. While maintaining an extremely high desalination rate, this results in a stable increase in the water flux of the reverse osmosis membrane.

[0019] Third, it avoids the addition of expensive chemical additives, making it highly promising for industrial applications. The solution of this invention completely abandons the involutionary approach of adding various surfactants or polymers to the aqueous phase, and solves the problem of uneven interface by utilizing extremely simple and controllable temperature, humidity, and hydrodynamic physical parameters. Existing continuous production lines can be upgraded simply by adding a very low-cost micro-evaporation balancing chamber between the coating section and the organic phase tank, without changing the main drive system. The technology is highly concealed, making it extremely easy to achieve large-scale industrial implementation and significantly reduce production costs. Attached Figure Description

[0020] Figure 1 A schematic diagram of the process flow for a continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control provided in an embodiment of the present invention; Figure 2This is a cross-sectional view of the core coating section of a continuous production line provided in an embodiment of the present invention.

[0021] Explanation of reference numerals in the attached figures: 1. Porous support membrane, 2. Aqueous phase tank, 3. Air knife, 4. Micro-evaporation balance chamber, 5. Organic phase tank, 6. Guide roller. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0023] like Figure 1 As shown, this invention provides a continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control. The overall process flow includes the following steps: Step 1, aqueous phase coating and air knife treatment; Step 2, steady-state parallel airflow micro-evaporation equilibrium treatment; Step 3, organic phase interfacial polymerization reaction; Step 4, heat treatment, water washing, and winding. This process breaks through the inherent technical bias of directly performing interfacial polymerization after aqueous phase coating in traditional industrial production lines, and introduces the crucial micro-evaporation equilibrium residence step.

[0024] Combination Figure 2 This paper provides a detailed description of the physical structure and yarn feeding process of the core coating section of the continuous production line. The porous support membrane 1, guided by a roll-to-roll take-up and unroller device and a series of guide rollers 6, runs continuously and smoothly at a preset yarn feeding speed. The porous support membrane 1 is first guided downwards by the guide rollers 6 and immersed in the aqueous phase tank 2, where it is fully coated and wetted with the aqueous solution below the liquid surface. Subsequently, the porous support membrane 1 is continuously drawn out of the aqueous phase tank 2 and passes through the air knife 3 during its upward oblique movement. The high-pressure airflow from the air knife 3 blows away excess large droplets from the membrane surface, forming an initial liquid film.

[0025] In existing processes, the membrane belt typically enters the subsequent organic phase tank 5 directly. However, this invention cleverly adds a micro-evaporation balancing chamber 4 to the transmission path between the air knife 3 and the organic phase tank 5. This micro-evaporation balancing chamber 4 is a sealed cavity with an independent temperature and humidity field control system, with only slits at both ends for the porous support membrane 1 to enter and exit. The membrane belt, after being processed by the air knife 3, enters the micro-evaporation balancing chamber 4 and travels at a uniform speed inside. During this time, a steady-state parallel airflow parallel to the direction of membrane belt travel is continuously introduced into the micro-evaporation balancing chamber 4, utilizing a controlled physical micro-evaporation time to release surface tension and induce capillary upwelling of monomers within the pores. After completing the micro-evaporation balancing process, the porous support membrane 1 is then introduced into the organic phase tank 5 by the guide roller 6, where an extremely rapid interfacial polymerization contact reaction occurs below the liquid surface of the organic phase tank 5, thereby generating an extremely thin polyamide separation layer in situ on the base membrane surface. Finally, it is led out for conventional heat treatment and washing.

[0026] It should be noted that the "steady-state parallel airflow" described in this invention refers to a macroscopic airflow direction that is substantially parallel to the direction of travel of the base film, aiming to avoid turbulence that vertically impacts the film surface. It does not demand an absolutely ideal laminar flow state in a fluid dynamics sense; those skilled in the art can achieve this using conventional industrial laminar flow hoods or uniform flow ducts. Furthermore, as a continuous preparation method, the wire feeding speed of the porous support membrane in this invention can be set according to conventional industrial production lines (preferably 5~20 m / min), and the physical length of the micro-evaporation balance chamber is designed to match the selected wire feeding speed and a residence time of 8~15 s. The wind speed of 0.5~1.2 m / s specified in this application refers to the absolute flow velocity of the airflow within the chamber.

[0027] In all the following embodiments and comparative examples, the porous support membrane 1 used is a commercially available conventional porous polysulfone support membrane with a width of 1.0 m. In the following embodiments and comparative examples 2 and 3 of the present invention, the effective physical length of the micro-evaporation balancing chamber is fixed at 2.0 m. Those skilled in the art will understand that the "residence time" of the base membrane in the chamber is uniquely determined by the "feeding speed" of the production line (i.e., residence time = chamber length / feeding speed).

[0028] Example 1

[0029] This embodiment provides a continuous preparation method for reverse osmosis membranes, the specific steps of which are as follows: Step 1: Prepare an aqueous solution consisting only of deionized water and 2.0 wt% m-phenylenediamine, without adding any surfactants or thickeners. The porous polysulfone support membrane is continuously immersed in the aqueous bath at a wire feed speed of 12 m / min for coating. After extraction, excess droplets on the surface are removed using an air knife with a working pressure of 0.1 MPa.

[0030] Step 2: The base film treated with an air knife is continuously introduced into a micro-evaporation balancing chamber with an effective length of 2.0 m for steady-state parallel airflow micro-evaporation balancing treatment. Since the wire feed speed is 12 m / min, the residence time of the base film in the chamber is precisely controlled to 10 s. The temperature inside the micro-evaporation balancing chamber is controlled at 28 ℃, and the relative humidity at 50% RH. A steady-state parallel airflow, consistent with the direction of the base film's movement, is introduced into the chamber. The absolute wind speed of this steady-state parallel airflow is 0.8 m / s, and the temperature and humidity are consistent with the chamber environment.

[0031] Step 3: The treated base film is continuously immersed in an organic phase bath at a temperature of 25 °C. The organic phase consists of isoparaffins and 0.1 wt% trimesoyl chloride, which generates a polyamide separation layer on the surface of the base film.

[0032] Step 4: Take out the membrane tape after reaction and put it into a hot air oven at 95 ℃ for continuous heat treatment for 3 min. Then rinse it continuously with deionized water at 50 ℃ and rewind it to obtain the reverse osmosis membrane.

[0033] Example 2

[0034] The preparation method in this embodiment is basically the same as that in Example 1, except that: In step one, in order to prolong the dwell time, the wire feed speed of the porous polysulfone support membrane is reduced to 8 m / min.

[0035] In step two, within a micro-evaporation equilibrium chamber with an effective length of 2.0 m, the residence time of the base film within the chamber is extended to 15 s; the chamber temperature is controlled at 30 ℃, the relative humidity is controlled at the lower limit of the scope of this invention (45% RH), and the absolute wind speed of the steady-state parallel airflow is increased to 1.2 m / s. The remaining formulation and steps are completely consistent with those in Example 1.

[0036] Example 3

[0037] The preparation method in this embodiment is basically the same as that in Example 1, except that: In step one, in order to shorten the dwell time, the wire feed speed of the porous polysulfone support membrane is increased to 15 m / min.

[0038] In step two, within a micro-evaporation equilibrium chamber with an effective length of 2.0 m, the residence time of the base film within the chamber is shortened to 8 s; the chamber temperature is controlled at 25 ℃, the relative humidity is controlled at the upper limit of the scope of this invention (55% RH), and the absolute wind speed of the steady-state parallel airflow is reduced to 0.5 m / s. The remaining formulation and steps are completely consistent with those in Example 1.

[0039] Comparative Example 1 This comparative example provides a continuous preparation method for a conventional reverse osmosis membrane, which differs from Example 1 in that: The porous polysulfone-supported membrane was coated with an aqueous phase and treated with an air knife at a wire feed speed of 12 m / min. Without passing through any sealed balancing chamber, it underwent a wire feed transition of less than 1 s in open air, and was then directly immersed in an organic phase bath containing trimesoyl chloride to undergo interfacial polymerization. The remaining formulation and steps were completely consistent with those in Example 1.

[0040] Comparative Example 2 This comparative example provides a method for preparing a reverse osmosis membrane, which differs from Example 1 in that: In step one, the wire feed speed is significantly reduced to 4.8 m / min.

[0041] In step two, due to the extremely slow wire feeding speed and the chamber length of 2.0 m, the base film resides in the micro-evaporation equilibrium chamber for up to 25 seconds. Simultaneously, the relative humidity within the chamber is controlled to be extremely low, at 20% RH. The remaining formulation and steps are completely consistent with Example 1.

[0042] Comparative Example 3 This comparative example provides a method for preparing a reverse osmosis membrane, which differs from Example 1 in that: The same yarn feed speed of 12 m / min as in Example 1 (i.e., the dwell time in the chamber was also 10 s) was used, but the relative humidity in the micro-evaporation balancing chamber was set to as high as 90% RH. The rest of the formulation and steps were completely consistent with Example 1.

[0043] Characterization and testing methods The reverse osmosis membranes prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests. The specific test methods and conditions are as follows: (1) Water flux and desalination rate test: The effective test area is 42 cm². 2 The cross-flow membrane evaluation device was used. The test feed water was a sodium chloride aqueous solution with a concentration of 2000 ppm. The test temperature was kept constant at 25 ℃, and the operating pressure was kept constant at 1.55 MPa. After the system ran continuously for 1 hour and the permeate stabilized, the permeate was collected, and the permeate flow rate per unit area and per unit time was calculated to obtain the water flux, expressed in L / (m²). 2 ·h); At the same time, the conductivity of raw water and permeate was measured using a high-precision conductivity meter, and the desalination rate was calculated, in units of %.

[0044] (2) Transverse uniformity test (CV value calculation): On the transverse side of the membrane roll after winding on the continuous production line, 10 membrane samples are randomly cut at equal intervals, and their water flux is tested according to the above test conditions. The ratio of the standard deviation to the mean of the water flux of these 10 samples is calculated to obtain the coefficient of variation (CV value), in %. The smaller the CV value, the more uniform the transverse coating of the membrane surface and the fewer the ripple defects caused by the air knife shearing force.

[0045] The specific test data results are shown in Table 1; Table 1 Performance test data for different embodiments and comparative examples

[0046] As can be seen from the test data above: (1) By comparing Examples 1-3 with Comparative Example 1, it can be seen that the traditional benchmark process (Comparative Example 1) has a lateral CV value of up to 5.7% because the stress ripples generated by the air knife are not released. However, after introducing the micro-evaporation balance chamber in this invention, the CV value of the examples drops sharply to 0.8%~1.2%. This strongly proves that under specific temperature and humidity and steady-state parallel airflow conditions, giving the liquid film a residence buffer time of 8~15 s can perfectly level the micro-ripples by utilizing surface tension, and completely eliminate local thickness unevenness and salt leakage defects on the continuous production line.

[0047] (2) Compared with Comparative Example 1, in a pure system without the addition of any chemical pore expanders or organic surfactants, the water flux of the present invention increased from 44.1 L / (m²) 2 •h) steadily increased to 50.9~54.7 L / (m 2 This is because controlled parallel flow microevaporation induces capillary upwelling of deep m-phenylenediamine, forming a nanoscale high-concentration reaction layer at the gas-liquid interface, which generates a thinner separation layer with a higher degree of effective cross-linking during interfacial polymerization.

[0048] (3) The criticality and necessity of the temperature and humidity window of the present invention were confirmed by comparing Example 1 with Comparative Examples 2 and 3. As shown in Comparative Example 2, when the humidity is too low (20% RH) and the residence time is too long, the liquid film dries out severely, resulting in extremely uneven monomer distribution during interfacial polymerization. The abnormal thickening of the polyamide layer in some areas causes the overall water flux to plummet to 31.6 L / (m²). 2In some areas, shrinkage stress creates tiny physical defects that lead to salt leakage, reducing the desalination rate to 98.62%. Simultaneously, the lateral CV value of the water flux spikes to 7.5%, rendering the process completely unusable. As shown in Comparative Example 3, when the humidity inside the chamber is too high (90% RH), the surface cannot generate micro-evaporation pull, deep pore monomers do not undergo capillary uplift, structural homogenization is not triggered, and ultimately, the performance degrades to almost the same level as the traditional process in Comparative Example 1.

[0049] In summary, without introducing any additional chemical reagents, this invention successfully overcomes the two major technical biases of "air knife ripple defects" and "flux limitation" in reverse osmosis membrane industrial production lines by precisely defining the local temperature and humidity field and physical residence time during the continuous coating process, achieving unexpected technical results.

[0050] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A continuous preparation method for reverse osmosis membranes based on micro-evaporation equilibrium control, characterized in that, Includes the following steps: Step 1: The porous support membrane is continuously immersed in an aqueous solution containing m-phenylenediamine for coating. Then, an air knife is used to blow away the excess droplets on the surface of the porous support membrane to obtain a base membrane with an aqueous liquid film attached to its surface. Step 2: The base film treated by the air knife is continuously introduced into the micro-evaporation balancing chamber for steady-state parallel airflow micro-evaporation balancing treatment; wherein, the temperature in the micro-evaporation balancing chamber is constantly controlled at 25~30 ℃, the relative humidity is constantly controlled at 45%~55% RH, the residence time of the base film in the micro-evaporation balancing chamber is 8~15 s, and a steady-state parallel airflow consistent with the direction of travel of the base film is introduced into the micro-evaporation balancing chamber, and the wind speed of the steady-state parallel airflow is controlled at 0.5~1.2 m / s; Step 3: The base film, after the steady-state parallel airflow micro-evaporation equilibrium treatment, is continuously immersed in an organic phase solution containing trimesoyl chloride to carry out an interfacial polymerization contact reaction, thereby generating a polyamide separation layer on the surface of the base film. Step 4: The reacted base membrane is drawn out and subjected to heat treatment and water washing in sequence, and finally wound up to obtain the reverse osmosis membrane.

2. The continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control according to claim 1, characterized in that, In step one, the aqueous solution consists of deionized water and m-phenylenediamine, without any additional additives, wherein the mass fraction of m-phenylenediamine in the aqueous solution is 1.5~2.5 wt%.

3. The continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control according to claim 1, characterized in that, In step one, the porous support membrane is a porous polysulfone support membrane.

4. The continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control according to claim 1, characterized in that, In step one, the working pressure of the air knife is controlled at 0.05~0.15 MPa.

5. The continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control according to claim 1, characterized in that, In step two, the micro-evaporation balance chamber is a sealed chamber with membrane belts at both ends. The temperature and relative humidity of the steady-state parallel airflow are consistent with the constant temperature and constant relative humidity inside the micro-evaporation balance chamber.

6. The continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control according to claim 1, characterized in that, In step three, the organic phase solution is composed of an isoparaffin solvent and trimesoyl chloride, wherein the mass fraction of trimesoyl chloride in the organic phase solution is 0.05~0.15 wt%.

7. The continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control according to claim 1, characterized in that, In step three, the contact reaction time of the base film immersed in the organic phase solution containing trimesoyl chloride is controlled to be 10-20 s.

8. The continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control according to claim 1, characterized in that, In step three, the temperature of the organic phase solution containing trimesoyl chloride is constantly controlled at 20~25 °C.

9. The continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control according to claim 1, characterized in that, In step four, the heat treatment is carried out continuously in a hot air oven, the temperature of the heat treatment is controlled at 85~100 ℃, and the time of the heat treatment is controlled at 2~5 min.

10. The continuous reverse osmosis membrane preparation method based on micro-evaporation equilibrium control according to claim 1, characterized in that, In step four, the water washing process involves continuously rinsing the base membrane with deionized water at a temperature of 40-60°C.

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