Application of adamantane-1, 3-diamine in preparation of reverse osmosis membrane with controllable desalination performance, reverse osmosis membrane as well as preparation method and application of reverse osmosis membrane

Abstract

The invention provides application of adamantane-1, 3-diamine in preparation of a reverse osmosis membrane with controllable desalination performance, the reverse osmosis membrane, a preparation method and application, and relates to the field of reverse osmosis membrane preparation. The reverse osmosis membrane with the controllable desalination performance comprises a polysulfone ultrafiltration membrane and a polyamide layer arranged on the surface of the polysulfone ultrafiltration membrane, wherein the polyamide layer is formed by carrying out interfacial polymerization reaction on a water-phase amine solution and an organic-phase acyl chloride solution and then carrying out heat treatment and curing; and the aqueous phase amine solution contains adamantane-1, 3-diamine. By adding adamantane-1, 3-diamine, a series of SWRO membranes which are identical in surface appearance, identical and similar in permeation flux and different in desalting performance are prepared, under the condition that an existing water production process and an existing membrane cleaning process are not changed, diversified requirements of different application scenes can be flexibly met, and the overall efficiency and economical efficiency of a system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of reverse osmosis membrane preparation, and in particular to an application of adamantane-1,3-diamine in the preparation of a reverse osmosis membrane with controllable desalination performance, a reverse osmosis membrane and a preparation method and application thereof, and in particular to a reverse osmosis membrane for seawater desalination, a method for regulating the selective permeability of a seawater desalination reverse osmosis membrane and an application thereof. Background Art

[0002] At present, reverse osmosis membrane desalination technology has been widely used in all aspects of production and life in islands and coastal areas. Seawater desalination reverse osmosis (SWRO) membrane technology usually operates at an operating pressure of 5.5MPa and is used to desalinate seawater into drinking water, industrial water, landscape water, and farmland irrigation water. Different application scenarios have different requirements for water quality, so SWRO membranes with different performance are required. For example, drinking water requires the SWRO membrane to have a desalination rate higher than 99.60% and a produced water conductivity lower than 200μS / cm to ensure the safety of drinking water quality; while farmland irrigation water only needs a desalination rate higher than 95.00% (produced water conductivity lower than 2500μS / cm) to meet the needs of crop growth, and too low conductivity may mean insufficient nutrients, which is not conducive to the healthy growth of crops.

[0003] For desalination plants, in order to meet the water quality requirements for different purposes, it is often necessary to significantly adjust the desalination process. This is not only time-consuming and labor-intensive, but sometimes even requires the addition of additional desalination process sections, increasing operating costs and complexity. In addition, if there are large differences in the surface morphology of SWRO membranes with different performance, different cleaning methods will need to be used during the membrane cleaning process, further increasing the difficulty and cost of maintenance. If the surface morphology of SWRO membranes with different performance is consistent, it can avoid developing or changing existing cleaning operations, simplifying the maintenance process and reducing operating costs.

[0004] The desalination performance can be regulated by adding aqueous or organic co-solvents, carbon nanomaterials, phase transfer catalysts, etc., but these methods usually cause the nanovesicles or fine leaf structures on the membrane surface to transform into a coarse structure of large leaf spread or leaf accumulation, which requires changing the cleaning process and increasing the complexity of the operation during the membrane cleaning process in the desalination process. In addition, there is an inevitable trade-off between the permeability and desalination rate of the membrane (trade-off effect). Therefore, it is a huge challenge to maintain the constant permeate flux while regulating the desalination performance of different SWRO membranes.

[0005] Therefore, in order to reduce the overall cost of seawater desalination, it is urgent to develop SWRO membranes with the same membrane surface morphology and permeation flux but different desalination performance. This membrane can flexibly meet the diverse needs of different application scenarios without changing the existing desalination process and operation, and improve the overall efficiency and economy of the system.

[0006] In view of this, the present invention is proposed. Summary of the invention

[0007] The purpose of the present invention is to provide an application of adamantane-1,3-diamine in the preparation of a reverse osmosis membrane with controllable desalination performance, a reverse osmosis membrane, a preparation method and an application thereof. The present invention achieves the purpose of regulating the desalination performance of the reverse osmosis membrane by adding adamantane-1,3-diamine, and the addition of adamantane-1,3-diamine can still ensure that the reverse osmosis membrane with controllable desalination performance is a series of reverse osmosis membranes with the same membrane surface morphology and the same or similar permeation flux. Therefore, the present invention can flexibly respond to various water production needs without changing the existing desalination process and operation.

[0008] In order to achieve the above-mentioned purpose of the present invention, the following technical solutions are particularly adopted:

[0009] In a first aspect, the present invention provides a use of adamantane-1,3-diamine in preparing a reverse osmosis membrane with controllable desalination performance.

[0010] Preferably, the reverse osmosis membranes with controllable desalination performance have the same membrane surface morphology and similar permeation flux.

[0011] Preferably, the NaCl rejection rate of the reverse osmosis membrane is regulated between 95.00 and 99.98%.

[0012] Preferably, the difference between the permeation fluxes of the reverse osmosis membranes is 0 to 2 L·m -2 ·h -1 the following.

[0013] Preferably, the reverse osmosis membrane comprises a polyamide layer; wherein the adamantane-1,3-diamine is used as an amine monomer for preparing the polyamide layer.

[0014] In a second aspect, the present invention provides a reverse osmosis membrane with controllable desalination performance, the reverse osmosis membrane with controllable desalination performance comprising a polysulfone ultrafiltration membrane and a polyamide layer disposed on the surface of the polysulfone ultrafiltration membrane;

[0015] The polyamide layer is formed by curing through heat treatment after an interfacial polymerization reaction between an aqueous amine solution and an organic acyl chloride solution; and the aqueous amine solution contains adamantane-1,3-diamine.

[0016] Preferably, the aqueous amine solution further comprises: m-phenylenediamine, camphorsulfonic acid and triethylamine.

[0017] Preferably, the aqueous amine solution comprises the following components by mass percentage:

[0018] Adamantane-1,3-diamine 0-0.6%, m-phenylenediamine 2.6-4.5%, camphorsulfonic acid 2.6-3.5%, triethylamine 1.2-2.6%, and the balance is water.

[0019] Preferably, the organic phase acyl chloride solution contains trimesoyl chloride and an organic solvent.

[0020] Preferably, in the organic phase acyl chloride solution, the mass percentage of trimesoyl chloride is 0.1-0.3%.

[0021] Preferably, the organic solvent is selected from any one of n-hexane, cyclohexane, Isopar G, Isopar H, Isopar L or Isopar M, or a combination of at least two thereof.

[0022] Preferably, the mass ratio of the aqueous phase amine solution to the organic phase acyl chloride solution is (0.1-5):1.

[0023] Preferably, the pore size of the polysulfone ultrafiltration membrane is 19-22 nm.

[0024] Preferably, the pure water flux of the polysulfone ultrafiltration membrane is 380 to 400 L·m -2 ·h -1 .

[0025] In a third aspect, the present invention provides a method for preparing a reverse osmosis membrane with controllable desalination performance as described in the second aspect, the preparation method comprising the following steps:

[0026] (1) After applying fluorine to the surface of the polysulfone ultrafiltration membrane with an aqueous amine solution, the membrane is left to stand and soak to obtain a composite membrane 1;

[0027] (2) pouring the organic phase acyl chloride solution onto the surface of the composite membrane 1 obtained in step (1) to perform interfacial polymerization to form a polyamide layer, thereby obtaining a composite membrane 2;

[0028] (3) heat-treating the composite membrane 2 obtained in step (2) to solidify the polyamide layer, thereby obtaining the reverse osmosis membrane with controllable desalination performance.

[0029] Preferably, in step (1), the temperature of the static soaking is 10 to 40° C., and the time of the static soaking is 30 to 60 seconds.

[0030] Preferably, in step (1), after the static infiltration, the method further comprises: removing excess solution on the surface of the composite membrane 1, and blowing the surface dry with nitrogen.

[0031] Preferably, in step (2), the temperature of the interfacial polymerization reaction is 10 to 40° C., and the time of the interfacial polymerization reaction is 30 to 120 seconds.

[0032] Preferably, in step (2), after the interfacial polymerization reaction, the method further comprises: removing excess solution on the surface of the second composite membrane and draining the solution.

[0033] Preferably, in step (3), the temperature of the heat treatment is 80 to 140° C., and the time of the heat treatment is 180 to 360 seconds.

[0034] Preferably, in step (3), after the heat treatment, the method further comprises: rinsing the membrane surface with deionized water.

[0035] In a fourth aspect, the present invention provides a reverse osmosis membrane with controllable desalination performance as described in the second aspect for use as a reverse osmosis membrane for seawater desalination. The prepared reverse osmosis membrane (SWRO membrane) can be applied to the field of seawater desalination, and can flexibly meet the diverse needs of different application scenarios without changing the existing desalination process and operation, thereby improving the overall efficiency and economy of the system.

[0036] Compared with the prior art, the present invention has the following beneficial effects:

[0037] (1) The present invention uses Ad with a stable cage-like tetrahedral structure as the second amine monomer in the aqueous phase, and utilizes its large size, rigidity and twisted structure as a steric hindrance unit at the molecular level to change the twisted orientation of the polyamide chain, further adjust its folding and compaction effects, and successfully prepare a SWRO membrane whose structure changes only at the submicroscopic level.

[0038] (2) The preparation method of the present invention is simple and easy to industrialize. Ad participates in the interfacial polymerization reaction as the second monomer in the aqueous phase. Compared with the traditional chemical modification or post-treatment method, the present invention does not need to add complicated production steps or additional equipment investment, thereby significantly simplifying the production process, reducing the difficulty of implementation, and being more conducive to large-scale production and application.

[0039] (3) The preparation method of the present invention has excellent control effect and significant cost-effectiveness. The amount of Ad added is only in a relatively small range of 0 to 0.6 wt%, but its control effect on the salt retention performance of the SWRO membrane is very prominent. Therefore, while maintaining low costs, it can flexibly meet the diverse needs of different application scenarios without changing the existing desalination process and operation, which helps to improve the overall efficiency and economy of the seawater desalination system. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 Surface SEM images of the reverse osmosis membranes prepared in Comparative Example 1 and Examples 1 to 5.

[0042] Among them, a is the reverse osmosis membrane of comparative example 1, b is the reverse osmosis membrane of embodiment 1, c is the reverse osmosis membrane of embodiment 2, d is the reverse osmosis membrane of embodiment 3, e is the reverse osmosis membrane of embodiment 4, and f is the reverse osmosis membrane of embodiment 5.

[0043] Figure 2 It is the WAXS scattering curve diagram of the reverse osmosis membrane prepared in Comparative Example 1 and Examples 1-5.

[0044] Figure 3 It is a schematic diagram of the three-Lorentz peak fitting of WAXS of the reverse osmosis membranes prepared in Comparative Example 1 and Examples 1 to 5.

[0045] Figure 4 The Kratky curve converted from the acquired SAXS curve.

[0046] Wherein, I is the reverse osmosis membrane of comparative example 1, II is the reverse osmosis membrane of embodiment 1, III is the reverse osmosis membrane of embodiment 2, IV is the reverse osmosis membrane of embodiment 3, V is the reverse osmosis membrane of embodiment 4, and VI is the reverse osmosis membrane of embodiment 5. DETAILED DESCRIPTION

[0047] Unless otherwise defined herein, scientific and technological terms used in conjunction with the present invention shall have the meanings commonly understood by those of ordinary skill in the art. The meaning and scope of the terms should be clear, however, in the case of any potential ambiguity, the definitions provided herein take precedence over any dictionary or external definitions. In this application, unless otherwise stated, the use of "or" means "and / or". In addition, the use of the term "including" and other forms is non-limiting.

[0048] It should be noted that specific details are described in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0049] The embodiments of the present invention will be described in detail below in conjunction with the embodiments and examples, but it will be appreciated by those skilled in the art that the following embodiments and examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified, proceed according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0050] In a first aspect, the present invention provides a use of adamantane-1,3-diamine in preparing a reverse osmosis membrane with controllable desalination performance.

[0051] As an optional embodiment, the reverse osmosis membrane with controllable desalination performance has the same membrane surface morphology and similar permeation flux.

[0052] In the present invention, the adamantane-1,3-diamine (Ad) can be used as the second monomer in the aqueous amine solution to prepare a series of SWRO membranes. Ad is a compound composed of an adamantane ring (a saturated carbocyclic compound composed of three fused cyclohexane rings arranged in a chair-shaped conformation) connected to two amine groups (-NH2). Among them, the adamantane part constitutes a stable cage-like tetrahedral structure, while the two amine groups provide nucleophilicity and reactivity. The present invention utilizes the large size, rigidity and twisted structure of Ad as a steric unit at the molecular level, changes the twisted orientation of the polyamide chain, and further adjusts its folding and compaction effects, thereby preparing a series of SWRO membranes whose apparent morphology has not changed, the permeate flux remains unchanged, but the desalination performance is different. Therefore, the present invention can flexibly respond to various water production needs without changing the existing desalination process and operation.

[0053] As an optional embodiment, the NaCl retention rate of the reverse osmosis membrane is regulated between 95.00 and 99.98%, for example, it can be 95.00%, 95.50%, 96.00%, 96.50%, 97.00%, 97.50%, 98.00%, 98.50%, 99.00%, 99.50%, 99.98%, etc.

[0054] As an optional embodiment, the difference between the permeation fluxes of the reverse osmosis membranes is 0 to 2 L·m -2 ·h -1 Below, for example, it can be 0L·m -2 ·h -1 , 0.2L·m -2 ·h -1 , 0.4L·m -2 ·h -1 , 0.5L·m-2 ·h -1 , 0.6L·m -2 ·h -1 , 0.8L·m -2 ·h -1 , 1L·m -2 ·h -1 , 1.2L·m -2 ·h -1 、1.4L·m -2 ·h -1 、1.5L·m -2 ·h -1 、1.6L·m -2 ·h -1 、1.8L·m -2 ·h -1 , 2L·m -2 ·h -1 wait.

[0055] As an optional embodiment, the reverse osmosis membrane includes a polyamide layer; wherein the adamantane-1,3-diamine is used as an amine monomer for preparing the polyamide layer.

[0056] In a second aspect, the present invention provides a reverse osmosis membrane with controllable desalination performance, the reverse osmosis membrane with controllable desalination performance comprising a polysulfone ultrafiltration membrane and a polyamide layer disposed on the surface of the polysulfone ultrafiltration membrane;

[0057] The polyamide layer is formed by curing through heat treatment after an interfacial polymerization reaction between an aqueous amine solution and an organic acyl chloride solution; and the aqueous amine solution contains adamantane-1,3-diamine.

[0058] In the present invention, by introducing adamantane-1,3-diamine (Ad) with a three-dimensional cage structure as the second aqueous phase monomer in the aqueous amine solution and embedding it into the polyamide network structure, the stacking morphology and spacing, folding and compaction structure of the polyamide benzene rings are regulated. The embedding of Ad into the APA network structure does not change the stacking morphology of the aggregates, so the water permeability of the SWRO membrane remains unchanged. However, due to the barrier effect of the rigid Ad molecules, the shoulder-to-shoulder stacking spacing d1 of the benzene rings in the polyamide network structure increases significantly at high concentrations of Ad, which changes the twisted orientation of the polyamide chain and weakens the folding degree of the polyamide chain and the compaction degree of the colloid particles. Therefore, the prepared SWRO membrane significantly regulates the salt retention performance of the SWRO membrane without changing the permeation flux. It should be noted that the present invention adds Ad to the aqueous solution and obtains a SWRO membrane with unchanged apparent morphology after interfacial polymerization.

[0059] As an optional embodiment, the aqueous amine solution further comprises: m-phenylenediamine, camphorsulfonic acid and triethylamine.

[0060] As an optional embodiment, the aqueous amine solution comprises the following components by mass percentage: 0-0.6% adamantane-1,3-diamine, 2.6-4.5% m-phenylenediamine, 2.6-3.5% camphorsulfonic acid, 1.2-2.6% triethylamine, and the balance is water.

[0061] Based on the total mass of the aqueous amine solution as 100%, the content of adamantane-1,3-diamine is 0 to 0.6%, for example, it can be 0.00001%, 0.00005%, 0.0001%, 0.0005%, 0.001%, 0.005%, 0.01%, 0.02%, 0.04%, 0.05%, 0.06%, 0.08%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, etc. (excluding the lower limit of 0%).

[0062] Taking the total mass of the aqueous amine solution as 100%, the content of m-phenylenediamine is 2.6-4.5%, for example, it can be 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, 3.6%, 3.7%, 3.8%, 3.9%, 4.0%, 4.1%, 4.2%, 4.3%, 4.4%, 4.5%, etc., preferably 3.7%.

[0063] Based on the total mass of the aqueous amine solution as 100%, the content of camphorsulfonic acid is 2.6-3.5%, for example, it can be 2.6%, 2.7%, 2.8%, 2.9%, 3.0%, 3.1%, 3.2%, 3.3%, 3.4%, 3.5%, etc., preferably 3.1%.

[0064] Taking the total mass of the aqueous amine solution as 100%, the content of triethylamine is 1.2-2.6%, for example, 1.2%, 1.3%, 1.4%, 1.5%, 1.6%, 1.7%, 1.8%, 1.9%, 2.0%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, etc., preferably 1.7%.

[0065] As an optional implementation, the organic phase acyl chloride solution contains trimesoyl chloride and an organic solvent.

[0066] As an optional embodiment, in the organic phase acyl chloride solution, the mass percentage of the trimesoyl chloride is 0.1-0.3%, for example, it can be 0.1%, 0.12%, 0.14%, 0.15%, 0.16%, 0.18%, 0.2%, 0.22%, 0.24%, 0.25%, 0.26%, 0.28%, 0.3%, etc.

[0067] As an optional embodiment, the organic solvent is selected from any one of n-hexane, cyclohexane, Isopar G, Isopar H, Isopar L or Isopar M, or a combination of at least two thereof, preferably Isopar G.

[0068] As an optional embodiment, the mass ratio of the aqueous amine solution to the organic acyl chloride solution is (0.1-5):1, for example, it can be 0.1:1, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, etc.

[0069] As an optional embodiment, the pore size of the polysulfone ultrafiltration membrane is 19 to 22 nm.

[0070] As an optional embodiment, the pure water flux of the polysulfone ultrafiltration membrane is 380 to 400 L·m -2 ·h -1 , for example, it can be 380L·m -2 ·h -1 、382L·m -2 ·h -1 、384L·m -2 ·h -1 、385L·m -2 ·h -1 、386L·m -2 ·h -1 、388L·m -2 ·h -1 、390L·m -2 ·h -1 、392L·m -2 ·h -1 、394L·m -2 ·h -1 、396L·m -2 ·h -1 、398L·m -2 ·h -1 、400L·m -2 ·h -1 wait.

[0071] In a third aspect, the present invention provides a method for preparing a reverse osmosis membrane with controllable desalination performance as described in the second aspect, the preparation method comprising the following steps:

[0072] (1) After applying fluorine to the surface of the polysulfone ultrafiltration membrane with an aqueous amine solution, the membrane is left to stand and soak to obtain a composite membrane 1;

[0073] (2) pouring the organic phase acyl chloride solution onto the surface of the composite membrane 1 obtained in step (1) to perform interfacial polymerization to form a polyamide layer, thereby obtaining a composite membrane 2;

[0074] (3) heat-treating the composite membrane 2 obtained in step (2) to solidify the polyamide layer, thereby obtaining the reverse osmosis membrane with controllable desalination performance.

[0075] As an optional embodiment, in step (1), the static infiltration temperature is 10-40°C, for example, it can be 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, etc., and the static infiltration time is 30-60s, for example, it can be 30s, 32s, 34s, 35s, 36s, 38s, 40s, 42s, 44s, 45s, 46s, 48s, 50s, 52s, 54s, 55s, 56s, 58s, 60s, etc.

[0076] As an optional embodiment, in step (1), after the static infiltration, the method further includes: removing excess solution on the surface of the composite membrane 1, and blowing the surface dry with nitrogen.

[0077] As an optional embodiment, in step (2), the temperature of the interfacial polymerization reaction is 10-40°C, for example, it can be 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, etc., and the time of the interfacial polymerization reaction is 30-120s, for example, it can be 30s, 32s, 34s, 35s, 36s, 38s, 40s, 42s, 44s, 45s, 46s, 48s, 50s, 60s, 70s, 80s, 90s, 100s, 110s, 120s, etc.

[0078] As an optional implementation, in step (2), after the interfacial polymerization reaction, the method further includes: removing excess solution on the surface of the second composite membrane and draining the solution.

[0079] As an optional embodiment, in step (3), the heat treatment temperature is 80-140°C, for example, 80°C, 85°C, 90°C, 95°C, 100°C, 105°C, 110°C, 115°C, 120°C, 125°C, 130°C, 135°C, 140°C, etc., preferably 125°C, and the heat treatment time is 180-360s, for example, 180 s, 185s, 190s, 195s, 200s, 205s, 210s, 215s, 220s, 225s, 230s, 235s, 240s, 245s, 250s, 260s, 270s, 280s, 290s, 300s, 310s, 320s, 330s, 340s, 350s, 360s, etc., preferably 235s.

[0080] As an optional embodiment, in step (3), after the heat treatment, the method further comprises: rinsing the membrane surface with deionized water.

[0081] In a fourth aspect, the present invention provides a controllable desalination performance reverse osmosis membrane as described in the second aspect for use as a controllable desalination performance reverse osmosis membrane for seawater desalination. The prepared controllable desalination performance reverse osmosis membrane (SWRO membrane) can be applied to the field of seawater desalination, and can flexibly meet the diverse needs of different application scenarios without changing the existing desalination process and operation, thereby improving the overall efficiency and economy of the system.

[0082] As an optional embodiment, the seawater desalination includes desalinating seawater into any one of drinking water, viewing water or farmland irrigation water.

[0083] The present invention is further described below by means of specific examples and comparative examples. However, it should be understood that these examples are only used for more detailed description and should not be construed as limiting the present invention in any form.

[0084] The sources of materials provided in the following embodiments and comparative examples are as follows:

[0085]

[0086]

[0095] Example 1

[0096] This embodiment provides a reverse osmosis membrane with controllable desalination performance, and the reverse osmosis membrane with controllable desalination performance is prepared by the following steps:

[0097] (1) First, the polysulfone support membrane is taken out from the deionized water soaked in sodium bisulfite and sandwiched between plexiglass plates. The membrane surface is washed with pure deionized water, and then the water droplets on the membrane surface are drained. Next, an aqueous solution containing adamantane-1,3-diamine, m-phenylenediamine, camphorsulfonic acid and triethylamine is evenly infiltrated on the surface of the polysulfone ultrafiltration membrane, and after standing at room temperature for 51 seconds, the droplets on the membrane surface are removed with nitrogen. Among them, the concentration of adamantane-1,3-diamine is 0.05wt%, the concentration of m-phenylenediamine is 3.7wt%, the concentration of camphorsulfonic acid is 3.1wt%, the concentration of triethylamine is 1.7wt%, and the balance is water.

[0098] (2) Pour the organic phase solution containing trimesoyl chloride evenly on the membrane surface treated in step (1), react at room temperature for 39 seconds, and then drain the excess solution on the membrane surface. The concentration of trimesoyl chloride is 0.19wt%, and the remainder is IsoparG solvent; and the mass ratio of the aqueous solution in step (1) to the organic phase solution in step (2) is 1:1.

[0099] (3) Finally, the membrane treated in step (2) was placed in an oven and cured at 125° C. for 235 seconds. After the curing was completed, the membrane surface was thoroughly rinsed with deionized water to remove unreacted residues and impurities, thereby obtaining a SWRO membrane.

[0100] Example 2

[0101] This embodiment provides a reverse osmosis membrane with controllable desalination performance, which is different from Embodiment 1 only in that: in step (1), the concentration of adamantane-1,3-diamine is 0.1 wt %, and the other conditions remain unchanged.

[0102] Example 3

[0103] This embodiment provides a reverse osmosis membrane with controllable desalination performance, which is different from Embodiment 1 only in that in step (1), the concentration of adamantane-1,3-diamine is 0.2 wt %, and the other conditions remain unchanged.

[0104] Example 4

[0105] This embodiment provides a reverse osmosis membrane with controllable desalination performance, which is different from Embodiment 1 only in that in step (1), the concentration of adamantane-1,3-diamine is 0.4 wt %, and the other conditions remain unchanged.

[0106] Example 5

[0107] This embodiment provides a reverse osmosis membrane with controllable desalination performance, which is different from Embodiment 1 only in that in step (1), the concentration of adamantane-1,3-diamine is 0.6 wt %, and the other conditions remain unchanged.

[0108] Example 6

[0109] This embodiment provides a reverse osmosis membrane with controllable desalination performance, which is different from Embodiment 1 only in that in step (2), the organic solvent is n-hexane, and the other conditions remain unchanged.

[0110] Example 7

[0111] This embodiment provides a reverse osmosis membrane with controllable desalination performance, which is different from Embodiment 1 only in that in step (2), the organic solvent is cyclohexane, and the other conditions remain unchanged.

[0112] Example 8

[0113] This embodiment provides a reverse osmosis membrane with controllable desalination performance, which is different from Embodiment 1 only in that in step (2), the organic solvent is Isopar H, and the other conditions remain unchanged.

[0114] Example 9

[0115] This embodiment provides a reverse osmosis membrane with controllable desalination performance, which is different from Embodiment 1 only in that in step (2), the organic solvent is Isopar L, and the other conditions remain unchanged.

[0116] Example 10

[0117] This embodiment provides a reverse osmosis membrane with controllable desalination performance, which is different from Embodiment 1 only in that in step (2), the organic solvent is Isopar M, and the other conditions remain unchanged.

[0118] Embodiment 11

[0119] This embodiment provides a reverse osmosis membrane with controllable desalination performance, which is different from Embodiment 1 only in that: in step (3), the heat treatment temperature is 90° C., the heat treatment time is 250 s, and the other conditions remain unchanged.

[0120] Example 12

[0121] This embodiment provides a reverse osmosis membrane with controllable desalination performance, which is different from Embodiment 1 only in that: in step (3), the heat treatment temperature is 140° C., the heat treatment time is 190 s, and the other conditions remain unchanged.

[0122] Comparative Example 1

[0123] This comparative example provides a reverse osmosis membrane, which is different from Example 1 only in that the concentration of adamantane-1,3-diamine is 0 wt %, and water is added to make the total amount of the aqueous solution 100%, and other conditions remain unchanged.

[0124] Comparative Example 2

[0125] This comparative example provides a reverse osmosis membrane with controllable desalination performance, which is different from Example 1 only in that in step (1), adamantane-1,3-diamine is replaced by adamantaneamine at a concentration of 0.1 wt %, and the other conditions remain unchanged.

[0126] Comparative Example 3

[0127] This comparative example provides a reverse osmosis membrane with controllable desalination performance, which is different from Example 1 only in that in step (1), adamantane-1,3-diamine is replaced by 1,3-adamantane dicarboxylic acid chloride with a concentration of 0.1 wt %, and the other conditions remain unchanged.

[0128] Test Example 1

[0129] Test samples: the reverse osmosis membranes with controllable desalination performance provided by Examples 1 to 12 and the reverse osmosis membranes provided by Comparative Examples 1 to 3.

[0130] Test method: In the present invention, the performance of the SWRO membranes prepared in Examples 1 to 5 and Comparative Example 1 was tested using a cross-flow filtration evaluation system. The prepared membrane samples were installed in 6 parallel filtration units, and the effective area of ​​each test cell was 29.2 cm 2 , the flow channel height is 1mm. First, pre-treat at 5.5MPa, 25±1℃ for 30 minutes, then use 32000ppm NaCl solution as raw water and adjust the pH to 7.0±0.5, and collect the produced water at 5.5MPa filtration pressure and 6LPM cross-flow rate.

[0131] The water flux and salt retention were calculated by the following formula:

[0132]

[0133] In the formula, J w is the water flux, S is the effective membrane area, ΔV is the amount of permeate collected within a certain time Δt; c p and c f are the solute concentrations of the permeate and feed solutions, respectively.

[0134] The test results are shown in Table 1 below:

[0135] Table 1

[0136]

[0137]

[0138] As shown in Table 1 above, the flux of the prepared SWRO membranes remained unchanged. The membrane permeation flux prepared in Examples 1 to 5 with the addition of adamantane-1,3-diamine was maintained at about 42 L·m -2 ·h -1 The NaCl rejection rate can be maintained above 95% and can be adjusted within the range of 95.00 to 99.99%. This fully demonstrates that the present invention can prepare SWRO membranes with similar permeation fluxes but different desalination performances. The SWRO membrane developed by the present invention not only has extremely similar permeation fluxes, but can also accurately adjust the salt retention performance for different application scenarios, thereby meeting diverse application needs.

[0139] Among them, when the Ad concentration is low, especially 0.1wt% (Example 2), the SWRO membrane can have a NaCl retention rate of up to 99.72%, slightly higher than Comparative Example 1 (99.66%), and has excellent desalination performance that exceeds most commercial membranes. This excellent membrane is particularly suitable for desalinating seawater into drinking water. As the Ad concentration increases to 0.2wt% (Example 3), the salt retention rate is 99.13%, which can meet the general industrial water demand. Further, when the Ad concentration increases to 0.4wt% (Example 4) and 0.5wt% (Example 5), the salt retention rate is adjusted to 97.61% and 95.48%, which can meet the needs of desalinating seawater into landscape water and farmland irrigation water, respectively.

[0140] Among them, the use of adamantane amine (Comparative Example 2) and 1,3-adamantanedicarboxylic acid chloride (Comparative Example 3) not only failed to prepare a SWRO membrane with the same or similar permeation flux, but also the permeation flux and NaCl retention rate of the prepared SWRO membrane were significantly reduced, which could not meet the relevant technical requirements of seawater desalination.

[0141] Test Example 2

[0142] Test samples: the reverse osmosis membranes provided in Examples 1 to 5 and the reverse osmosis membrane provided in Comparative Example 1.

[0143] Test method: Use scanning electron microscope to observe each reverse osmosis membrane sample.

[0144] The test results are as follows Figure 1 As shown: (a) is comparative example 1, (b) is example 1, (c) is example 2, (d) is example 3, (e) is example 4, and (f) is example 5.

[0145] like Figure 1 As shown, Examples 1 to 5 of the present invention and Comparative Example 1 all have the same membrane surface morphology, so it is possible to avoid developing or changing the existing cleaning operation, simplify the maintenance process, and reduce the operating cost. This not only improves the overall efficiency of the system, but also enhances the economy. In summary, the SWRO membrane developed by the present invention not only has high flexibility in performance, but also shows significant advantages in maintenance and operating costs, providing strong support for the efficient and economical operation of the seawater desalination system.

[0146] Test Example 3

[0147] Test samples: the reverse osmosis membranes provided in Examples 1 to 5 and the reverse osmosis membrane provided in Comparative Example 1.

[0148] Test method: In order to further explain the above effects, the SWRO membranes prepared in Examples 1 to 5 and Comparative Example 1 were characterized and analyzed. WAXS technology was used when the scattering vector q was 0.7 to 2.5 The molecular structural information of the polyamide separation layer was obtained within the range of Figure 2 By fitting the scattering curve using the three-Lorentz peak model, three scattering peaks are obtained. Figure 3 Then the scattering peaks were calculated by the formula d=2π / q to obtain the corresponding benzene ring shoulder-to-shoulder stacking spacing d1, face-to-face stacking spacing d2 and hydrogen bond stacking spacing d3.

[0149] The results of the benzene ring spacing parameters obtained by fitting the WAXS scattering curve are shown in Table 2 below:

[0150] Table 2

[0151]

[0152] As shown in Table 2 above, after Ad is connected to the polyamide chain during the polymerization process, it does play a regulatory role in the stacking distance of submicroscopic benzene rings.

[0153] Specifically, d1 changes less at lower Ad concentrations (Comparative Example 1, Examples 1-2), maintaining about At high concentrations, they increased to (Example 3), (Example 4) and (Example 5). d2 is almost unchanged, and is maintained at about At lower concentrations (Comparative Example 1, Examples 1-2), d3 remains about As the concentration of Ad further increased, (Example 3), (Example 4) and (Example 5).

[0154] It can be seen that the analysis of the molecular stacking morphology and spacing of polyamide chains shows that after high concentration of Ad is embedded in the polyamide network structure, the polymer chain spacing d1 is significantly increased, the twisted orientation of polyamide is changed, and the Figure 4 The folding degree of the polyamide chain is weakened (the intensity of the Kratky peak is weakened).

[0155] And if Figure 1 As shown, the apparent morphology of the reverse osmosis membrane with controllable desalination performance has not changed. Therefore, Ad only changes the structural parameters of the submicroscopic level inside the polyamide, thereby realizing a preparation method of the present invention for regulating the performance of a seawater desalination reverse osmosis membrane without changing the apparent morphology.

[0156] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. Application of adamantane-1,3-diamine in the preparation of reverse osmosis membranes with controllable desalination performance.

2. The use according to claim 1, characterized in that: The controllable desalination performance reverse osmosis membrane has the same membrane surface morphology and similar permeation flux; Preferably, the NaCl rejection rate of the reverse osmosis membrane is regulated between 95.00 and 99.98%; Preferably, the difference between the permeation fluxes of the reverse osmosis membranes is 0 to 2 L·m -2 ·h -1 ; Preferably, the reverse osmosis membrane comprises a polyamide layer; wherein the adamantane-1,3-diamine is used as an amine monomer for preparing the polyamide layer.

3. A reverse osmosis membrane with controllable desalination performance, characterized in that: The reverse osmosis membrane with controllable desalination performance comprises a polysulfone ultrafiltration membrane and a polyamide layer arranged on the surface of the polysulfone ultrafiltration membrane; The polyamide layer is formed by curing through heat treatment after an interfacial polymerization reaction between an aqueous amine solution and an organic acyl chloride solution; and the aqueous amine solution contains adamantane-1,3-diamine.

4. The reverse osmosis membrane with controllable desalination performance according to claim 3, characterized in that: The aqueous amine solution also includes: m-phenylenediamine, camphorsulfonic acid and triethylamine; Preferably, the aqueous amine solution comprises the following components by mass percentage: 0-0.6% adamantane-1,3-diamine, 2.6-4.5% m-phenylenediamine, 2.6-3.5% camphorsulfonic acid, 1.2-2.6% triethylamine, and the balance is water; Preferably, the organic phase acyl chloride solution contains trimesoyl chloride and an organic solvent; Preferably, in the organic phase acyl chloride solution, the mass percentage of trimesoyl chloride is 0.1-0.3%; Preferably, the organic solvent is selected from any one or a combination of at least two of n-hexane, cyclohexane, Isopar G, Isopar H, Isopar L or Isopar M; Preferably, the mass ratio of the aqueous phase amine solution to the organic phase acyl chloride solution is (0.1-5):

1.

5. The reverse osmosis membrane with controllable desalination performance according to claim 3, characterized in that: The pore size of the polysulfone ultrafiltration membrane is 19 to 22 nm; Preferably, the pure water flux of the polysulfone ultrafiltration membrane is 380 to 400 L·m -2 ·h -1 .

6. A method for preparing a reverse osmosis membrane with controllable desalination performance according to any one of claims 3 to 5, characterized in that: The preparation method comprises the following steps: (1) After applying fluorine to the surface of the polysulfone ultrafiltration membrane with an aqueous amine solution, the membrane is left to stand and soak to obtain a composite membrane 1; (2) pouring the organic phase acyl chloride solution onto the surface of the composite membrane 1 obtained in step (1) to perform interfacial polymerization to form a polyamide layer, thereby obtaining a composite membrane 2; (3) heat-treating the composite membrane 2 obtained in step (2) to solidify the polyamide layer, thereby obtaining the reverse osmosis membrane with controllable desalination performance.

7. The method for preparing a reverse osmosis membrane with controllable desalination performance according to claim 6, characterized in that: In step (1), the temperature of the static soaking is 10 to 40° C., and the time of the static soaking is 30 to 60 seconds; Preferably, in step (1), after the static infiltration, the method further comprises: removing excess solution on the surface of the composite membrane 1, and blowing the surface dry with nitrogen.

8. The method for preparing a reverse osmosis membrane with controllable desalination performance according to claim 6, characterized in that: In step (2), the temperature of the interfacial polymerization reaction is 10 to 40° C., and the time of the interfacial polymerization reaction is 30 to 120 seconds; Preferably, in step (2), after the interfacial polymerization reaction, the method further comprises: removing excess solution on the surface of the second composite membrane and draining the solution.

9. The method for preparing a reverse osmosis membrane with controllable desalination performance according to claim 6, characterized in that: In step (3), the heat treatment temperature is 80 to 140° C., and the heat treatment time is 180 to 360 seconds; Preferably, in step (3), after the heat treatment, the method further comprises: rinsing the membrane surface with deionized water.

10. Use of a reverse osmosis membrane with controllable desalination performance according to any one of claims 3 to 5 in the preparation of a reverse osmosis membrane for seawater desalination; And / or, the seawater desalination includes desalinating seawater into any one of drinking water, viewing water or farmland irrigation water.

Images