Scale inhibition reverse osmosis membrane and preparation method thereof
By alternately depositing ZrO2-TiO2 composite nano-coatings on the surface of the reverse osmosis membrane substrate, the problem of scaling in reverse osmosis membranes was solved, achieving efficient scale inhibition and water flux, and extending the service life of the membrane.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-26
- Publication Date
- 2026-03-10
AI Technical Summary
Existing reverse osmosis membranes are prone to scaling during operation, which leads to decreased membrane flux, increased operating pressure, and increased cleaning frequency. Furthermore, existing membrane surface modification technologies are not effective at inhibiting scaling, and hydrophilic groups are easily oxidized, hydrolyzed, and detached, resulting in a short service life.
Alternating ZrO2-TiO2 composite nanocoatings are deposited on the surface of a reverse osmosis membrane substrate. The coating thickness and the atomic ratio of Zr to Ti are controlled to form a hydrophilic, oleophobic, and highly negatively charged membrane surface. The uniformity and stability of the coating are ensured by atomic deposition.
It improves the scale inhibition performance of reverse osmosis membranes, ensures water flux, extends membrane lifespan, and reduces the risk of scaling.
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Figure CN121623569A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of water treatment, and particularly relates to a scale-inhibiting reverse osmosis membrane and a preparation method thereof. BACKGROUND
[0002] Reverse osmosis technology has been widely used in seawater desalination, brackish water desalination, industrial wastewater reuse and municipal water supply due to its high desalination and purification capacity. However, scale formation is prone to occur on the reverse osmosis membrane during operation, which is one of the main bottlenecks restricting the long-term stable operation of the reverse osmosis membrane.
[0003] The scale formation is mainly caused by the concentration and precipitation of hardness ions such as calcium and magnesium and anions such as sulfate and carbonate on the membrane surface, and the adsorption of organic matters in water on the membrane surface, which aggravates the scale formation problem. The scale formation can lead to the decrease of membrane flux, the increase of operation pressure and the increase of cleaning frequency, which not only reduces the treatment efficiency of the system, but also shortens the service life of the membrane and increases the operation cost.
[0004] In order to solve the scale formation problem of the reverse osmosis membrane, various methods have been adopted in the prior art, such as removing part of the scale-forming ions by pretreatment, adding scale inhibitors and optimizing operation parameters. However, these methods have the disadvantages of limited scale inhibition effect, high cost and possible introduction of secondary pollution. In recent years, membrane surface modification technology has become a research hotspot. By changing the physical and chemical properties of the membrane surface, the adhesion of scale-forming substances on the membrane surface is reduced. The existing membrane surface modification technology is mainly to construct a hydrophilic layer on the membrane surface by grafting, so as to reduce the surface free energy of the reverse osmosis membrane. However, the hydrophilic groups are easy to oxidize, hydrolyze and fall off during long-term operation, and the service life is relatively short, and the scale inhibition effect is poor. SUMMARY
[0005] The present application aims to provide a scale-inhibiting reverse osmosis membrane and a preparation method thereof, which solves the problem of poor scale inhibition effect of the existing reverse osmosis membrane.
[0006] To achieve the above-mentioned purpose, the present application provides a scale-inhibiting reverse osmosis membrane, which comprises a reverse osmosis membrane substrate and a ZrO2-TiO2 composite nano coating attached to the surface of the reverse osmosis membrane substrate.
[0007] Preferably, the ZrO2-TiO2 composite nano coating is an alternating ZrO2 layer and TiO2 layer.
[0008] Preferably, the reverse osmosis membrane substrate is an aromatic polyamide reverse osmosis membrane, and the thickness of the ZrO2-TiO2 composite nano coating is 5-10 nm.
[0009] Preferably, the atomic ratio of Zr to Ti in the ZrO2-TiO2 composite nano coating is 2.5-3.5:1.
[0010] Preferably, the reverse osmosis membrane with the ZrO2-TiO2 composite nanocoating has a contact angle with water of ≤15° and a contact angle with oil of ≥150°, and the surface of the reverse osmosis membrane has a zeta potential of -30 mV ± 5 mV. Preferably, the reverse osmosis membrane with the ZrO2-TiO2 composite nanocoating has a contact angle with water of ≤15° and a contact angle with oil of ≥150°, and the surface of the reverse osmosis membrane has a zeta potential of -30 mV ± 5 mV.
[0011] A method for preparing the reverse osmosis membrane with scale inhibition as described above, comprising the following steps: S1, pretreating the reverse osmosis membrane substrate; S2, placing the pretreated reverse osmosis membrane substrate into the reaction cavity of an atomic layer deposition device, and vacuumizing the reaction cavity to a pressure of ≤1 Pa; S3, introducing a zirconium source precursor into the reaction cavity, pulse processing, and then introducing an inert gas to purge the pulse; S4, introducing ozone into the reaction cavity, and allowing the ozone to react with the zirconium source precursor to generate a ZrO2 thin layer; S5, introducing a titanium source precursor into the reaction cavity, pulse processing, and then introducing an inert gas to purge the pulse; S6, introducing ozone into the reaction cavity, and allowing the ozone to react with the titanium source precursor to generate a TiO2 thin layer; S7, repeating S3-S6 for 20-50 cycles to obtain a ZrO2-TiO2 composite nanocoating; S8, stopping the introduction of the gas, and naturally cooling the temperature of the reaction cavity to room temperature to obtain the reverse osmosis membrane with scale inhibition.
[0012] Preferably, in S1, the pretreatment of the reverse osmosis membrane substrate comprises the following steps: S11, first ultrasonically cleaning the reverse osmosis membrane substrate with deionized water for 20-30 minutes, and the temperature of the deionized water is 30-40°C; S12, ultrasonically cleaning with ethanol for 10-15 minutes; S13, placing the cleaned reverse osmosis membrane substrate into a forced air drying oven at 60-80°C and drying for 1-2 hours.
[0013] Preferably, in S3, the zirconium source precursor is tetrakis(dimethylamino)zirconium, the deposition temperature is 150°C ± 5°C, the pulse time is 0.1-0.5 s, the inert gas is nitrogen or argon, the inert gas flow rate is 100-200 sccm, and the inert gas introduction time is 5-10 s.
[0014] Preferably, in S4 and S6, the concentration of the ozone is 80 -100 , and the introduction flow rate is 50-100 sccm.
[0015] Preferably, in step S5, the titanium source precursor is tetrakis(dimethylamino)titanium, the deposition temperature is 150℃±5℃, and the pulse time is 0.1s-0.5s; the inert gas is nitrogen or argon, the inert gas flow rate is 100sccm-200sccm, and the inert gas introduction time is 5s-10s.
[0016] The advantages and positive effects of the scale-inhibiting reverse osmosis membrane and its preparation method described in this invention are as follows: This invention uses atomic deposition to alternately deposit a zirconium oxide and titanium oxide composite nano-coating on the surface of a reverse osmosis membrane substrate, controlling the thickness of the composite nano-coating and the atomic ratio of Zr to Ti, thereby obtaining a hydrophilic, oleophobic, and highly negatively charged reverse osmosis membrane, improving the scale inhibition performance of the reverse osmosis membrane, ensuring the water flux of the reverse osmosis membrane, and increasing the service life of the reverse osmosis membrane.
[0017] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description
[0018] Figure 1 This is a flowchart of the preparation method according to an embodiment of the present invention. Detailed Implementation
[0019] In this application, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. In case of any inconsistency, the meaning set forth in this specification or derived from the content described herein shall prevail. Furthermore, the terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit the scope of this application.
[0020] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.
[0021] A scale-inhibiting reverse osmosis membrane includes a reverse osmosis membrane substrate, wherein a ZrO2-TiO2 composite nano-coating is attached to the surface of the reverse osmosis membrane substrate.
[0022] The ZrO2-TiO2 composite nanocoating consists of alternating ZrO2 and TiO2 layers.
[0023] The reverse osmosis membrane substrate is an aromatic polyamide reverse osmosis membrane, which has good desalination performance and mechanical properties, and is conducive to improving the service life of the reverse osmosis membrane.
[0024] The thickness of the ZrO2-TiO2 composite nanocoating is 5nm-10nm. The very thin thickness of the ZrO2-TiO2 composite nanocoating results in low mass transfer resistance for water molecules, which is beneficial for increasing water flux.
[0025] The atomic ratio of Zr to Ti in the ZrO2-TiO2 composite nanocoating is 2.5-3.5:1, preferably 2.8-3.2:1. By controlling the atomic ratio of Zr to Ti, the contact angle between the ZrO2-TiO2 composite nanocoating and water is ≤15°, and the contact angle with oil is ≥150°, thus improving the surface properties of the reverse osmosis membrane. The potential is -30mV ± 5mV.
[0026] Zr 4+ Ti has a smaller ionic radius and higher electronegativity, resulting in a stronger attraction to oxygen atoms and a more stable adsorption of water molecules to generate a high density of surface hydroxyl groups. These hydroxyl groups can form strong hydrogen bonds with water molecules, allowing water molecules to spread rapidly on the membrane surface and reducing the water contact angle. 4+ ZrO2 has a slightly larger ionic radius and lower electronegativity, resulting in weaker hydrogen bonding with water molecules. When the atomic ratio of Zr to Ti in the composite nanocoating is less than 2.5:1, the proportion of TiO2 with low hydroxyl density increases, the total number of hydroxyl groups on the surface decreases, hydrogen bonding weakens, water molecule spreading resistance increases, the water contact angle is >15°, and hydrophilicity decreases. Excessive ZrO2 leads to surface hydroxyl group aggregation, resulting in excessively strong local hydrogen bonding but decreased overall interfacial compatibility, which in turn hinders the uniform spreading of water molecules, and the water contact angle also increases, leading to an imbalance in hydrophilicity. The surface energy of ZrO2 is slightly higher than that of TiO2. When the atomic ratio of Zr to Ti in the composite nanocoating is less than 2.5:1, the surface energy decreases, and the weak polarity of TiO2 easily forms local adsorption with oil molecules, weakening oleophobicity. When the atomic ratio of Zr to Ti in the composite nanocoating is greater than 2.5:1, the surface energy is too high, and oil molecules spread on the film surface through van der Waals forces, weakening oleophobicity. 4+ The strong polarization of Zr is beneficial for forming a strong negative charge on the membrane surface, which is conducive to improving the scale inhibition effect of reverse osmosis membranes. However, excessive Zr... 4+ It will disrupt the uniformity of charge distribution, leading to Potential fluctuations affect scale inhibition performance.
[0027] The contact angle between the reverse osmosis membrane and water is ≤15°, enabling the rapid formation of a continuous hydration layer on the membrane surface, thus isolating calcium from the water. 2+ Mg 2+ The direct contact between hardness ions and the reverse osmosis membrane surface reduces the crystallization and precipitation of heavy metal ions, thus achieving scale inhibition. Furthermore, its high hydrophilicity reduces the frictional resistance between water molecules and the reverse osmosis membrane, increasing the mass transfer rate and pure water flux. The contact angle between the reverse osmosis membrane and oil is ≥150°, which significantly reduces the interfacial tension between oily organic matter in the water and the reverse osmosis membrane surface, reducing the adsorption of organic matter on the membrane surface, preventing its accumulation, and ensuring the water flux of the reverse osmosis membrane. With a potential of -30mV±5mV, the reverse osmosis membrane has strong negative charge and is attracted to positively charged calcium in water. 2+ Mg 2+ Ions of equal hardness generate electrostatic repulsion, reducing the hardness of Ca. 2+ Mg 2+ The deposition of ions on the reverse osmosis membrane inhibits crystallization and improves the membrane's scale inhibition effect. Simultaneously, it reduces the adsorption of positively charged colloidal particles in the water onto the membrane, further lowering the risk of scaling and increasing water flux.
[0028] like Figure 1 As shown, the preparation method of the above-mentioned scale-inhibiting reverse osmosis membrane includes the following steps: S1. Pretreatment of the reverse osmosis membrane substrate.
[0029] The pretreatment of reverse osmosis membrane substrate includes the following steps: S11. The reverse osmosis membrane substrate is first ultrasonically cleaned with deionized water for 20-30 minutes at a temperature of 30℃-40℃ to remove particulate matter attached to the surface.
[0030] S12. Use ethanol for ultrasonic cleaning for 10-15 minutes to remove organic pollutants.
[0031] S13. Place the cleaned reverse osmosis membrane substrate in a forced-air drying oven at 60℃-80℃ and dry for 1-2 hours.
[0032] The clean surface of the reverse osmosis membrane substrate after pretreatment is beneficial to improving the bonding strength and deposition uniformity between the ZrO2-TiO2 composite nano-coating and the reverse osmosis membrane substrate.
[0033] S2. Place the pretreated reverse osmosis membrane substrate into the reaction chamber of the atomic layer deposition equipment, ensuring that the surface of the reverse osmosis membrane substrate is flat and wrinkle-free. Evacuate the reaction chamber to a pressure ≤1Pa. The vacuum environment can prevent impurities in the air from interfering with the deposition process and ensure the purity of the coating.
[0034] S3. Introduce the zirconium source precursor into the reaction chamber, perform pulse treatment, and then purge with an inert gas pulse.
[0035] The zirconium source precursor is tetra(dimethylamino)zirconium, the deposition temperature is 150℃±5℃, and the pulse duration is 0.1s-0.5s. Pulsed processing ensures uniform deposition of tetra(dimethylamino)zirconium on the surface of the reverse osmosis membrane substrate. Nitrogen or argon is used as the inert gas, with a flow rate of 100sccm-200sccm and an inert gas introduction time of 5s-10s. The inert gas is introduced into the reaction chamber to remove unreacted precursors and byproducts, improving the purity and uniformity of the zirconium source precursor deposition.
[0036] S4. Ozone is introduced into the reaction chamber, and the ozone reacts with the zirconium source precursor to generate a thin layer of ZrO2.
[0037] The ozone concentration was 80. -100 The flow rate was 50-100 sccm. The high concentration of ozone reacted fully with the zirconium source precursor to obtain a ZrO2 thin layer.
[0038] S5. Introduce titanium source precursor into the reaction chamber, perform pulse treatment, and then purge with inert gas pulse.
[0039] The titanium source precursor is tetrakis(dimethylamino)titanium, the deposition temperature is 150℃±5℃, and the pulse time is 0.1s-0.5s. The inert gas is nitrogen or argon, the inert gas flow rate is 100sccm-200sccm, and the inert gas introduction time is 5s-10s.
[0040] S6. Ozone is introduced into the reaction chamber, and the ozone reacts with the titanium source precursor to generate a TiO2 thin layer.
[0041] The ozone concentration was 80. -100 The flow rate was 50-100 sccm. The high concentration of ozone reacted fully with the zirconium source precursor to obtain a TiO2 thin layer.
[0042] S7. Repeat S3-S6, and perform cyclic deposition 20-50 times to obtain a ZrO2-TiO2 composite nano-coating with a thickness of 5nm-10nm.
[0043] S8. Stop the gas supply and allow the reaction chamber temperature to cool naturally to room temperature to obtain an anti-scaling reverse osmosis membrane.
[0044] Atom deposition is employed to uniformly deposit an oxide layer layer by layer on the reverse osmosis membrane substrate. The resulting composite nano-coating exhibits high density, preventing metal ions from penetrating into the coating and inhibiting scaling on the reverse osmosis membrane. Atom deposition is used, and the process parameters are precisely controlled to ensure the atomic ratio of Zr to Ti, guaranteeing the performance stability of the reverse osmosis membrane. Atom deposition is performed at approximately 150℃, which does not damage the structure of the aromatic polyamide substrate, improving the adhesion between the coating and the substrate and ensuring long-term effective and stable operation of the coating. This contributes to enhancing the long-term effective scale inhibition effect of the reverse osmosis membrane.
[0045] Example 1 A scale-inhibiting reverse osmosis membrane includes a reverse osmosis membrane substrate, wherein a ZrO2-TiO2 composite nano-coating is attached to the surface of the reverse osmosis membrane substrate.
[0046] The ZrO2-TiO2 composite nanocoating consists of alternating ZrO2 and TiO2 layers.
[0047] The reverse osmosis membrane substrate is an aromatic polyamide reverse osmosis membrane.
[0048] The thickness of the ZrO2-TiO2 composite nanocoating is 8 nm.
[0049] The atomic ratio of Zr to Ti in the ZrO2-TiO2 composite nanocoating is 3:1.
[0050] The method for preparing the above-mentioned scale-inhibiting reverse osmosis membrane includes the following steps: S1. Pretreatment of the reverse osmosis membrane substrate.
[0051] The pretreatment of reverse osmosis membrane substrate includes the following steps: S11. The reverse osmosis membrane substrate is first ultrasonically cleaned with 40℃ deionized water for 20 minutes.
[0052] S12. Use ethanol for ultrasonic cleaning for 10 minutes to remove organic pollutants.
[0053] S13. Place the cleaned reverse osmosis membrane substrate in an 80°C forced-air drying oven and dry for 1 hour.
[0054] S2. Place the pretreated reverse osmosis membrane substrate into the reaction chamber of the atomic layer deposition equipment, and evacuate the reaction chamber to a pressure ≤1Pa.
[0055] S3. Introduce the zirconium source precursor into the reaction chamber, perform pulse treatment, and then purge with an inert gas pulse.
[0056] The zirconium source precursor was tetra(dimethylamino)zirconium, the deposition temperature was 150℃, and the pulse time was 0.3s. The pulse treatment ensured uniform deposition of tetra(dimethylamino)zirconium on the surface of the reverse osmosis membrane substrate. The inert gas was nitrogen or argon, the inert gas flow rate was 200 sccm, and the inert gas introduction time was 5s.
[0057] S4. Ozone is introduced into the reaction chamber, and the ozone reacts with the zirconium source precursor to generate a thin layer of ZrO2.
[0058] The concentration of ozone is 100. The flow rate was 100 sccm. The high concentration of ozone reacted fully with the zirconium source precursor to obtain a ZrO2 thin layer.
[0059] S5. Introduce titanium source precursor into the reaction chamber, perform pulse treatment, and then purge with inert gas pulse.
[0060] The titanium source precursor was tetrakis(dimethylamino)titanium, the deposition temperature was 150℃, and the pulse time was 0.1s. The inert gas was nitrogen or argon, the inert gas flow rate was 200 sccm, and the inert gas introduction time was 5s.
[0061] S6. Ozone is introduced into the reaction chamber, and the ozone reacts with the titanium source precursor to generate a TiO2 thin layer.
[0062] The ozone concentration was 80. The flow rate was 80 sccm. The high concentration of ozone reacted fully with the zirconium source precursor to obtain a TiO2 thin layer.
[0063] S7. Repeat S3-S6 for 40 cycles to obtain an 8nm thick ZrO2-TiO2 composite nano-coating.
[0064] S8. Stop the gas supply and allow the reaction chamber temperature to cool naturally to room temperature to obtain an anti-scaling reverse osmosis membrane.
[0065] Example 2 A scale-inhibiting reverse osmosis membrane includes a reverse osmosis membrane substrate, wherein a ZrO2-TiO2 composite nano-coating is attached to the surface of the reverse osmosis membrane substrate.
[0066] The ZrO2-TiO2 composite nanocoating consists of alternating ZrO2 and TiO2 layers.
[0067] The reverse osmosis membrane substrate is an aromatic polyamide reverse osmosis membrane.
[0068] The thickness of the ZrO2-TiO2 composite nanocoating is 5 nm.
[0069] The atomic ratio of Zr to Ti in the ZrO2-TiO2 composite nanocoating is 2.8:1.
[0070] The method for preparing the above-mentioned scale-inhibiting reverse osmosis membrane includes the following steps: S1. Pretreatment of the reverse osmosis membrane substrate.
[0071] The pretreatment of reverse osmosis membrane substrate includes the following steps: S11. First, ultrasonically clean the reverse osmosis membrane substrate with 30°C deionized water for 30 minutes.
[0072] S12. Use ethanol for ultrasonic cleaning for 10 minutes to remove organic pollutants.
[0073] S13. Place the cleaned reverse osmosis membrane substrate in a 70°C forced-air drying oven and dry for 2 hours.
[0074] S2. Place the pretreated reverse osmosis membrane substrate into the reaction chamber of the atomic layer deposition equipment, and evacuate the reaction chamber to a pressure ≤1Pa.
[0075] S3. Introduce the zirconium source precursor into the reaction chamber, perform pulse treatment, and then purge with an inert gas pulse.
[0076] The zirconium source precursor was tetra(dimethylamino)zirconium, the deposition temperature was 145℃, and the pulse time was 0.4s. The pulse treatment ensured uniform deposition of tetra(dimethylamino)zirconium on the surface of the reverse osmosis membrane substrate. The inert gas was nitrogen or argon, the inert gas flow rate was 100 sccm, and the inert gas introduction time was 7s.
[0077] S4. Ozone is introduced into the reaction chamber, and the ozone reacts with the zirconium source precursor to generate a thin layer of ZrO2.
[0078] The ozone concentration was 80. The flow rate was 80 sccm. The high concentration of ozone reacted fully with the zirconium source precursor to obtain a ZrO2 thin layer.
[0079] S5. Introduce titanium source precursor into the reaction chamber, perform pulse treatment, and then purge with inert gas pulse.
[0080] The titanium source precursor was tetrakis(dimethylamino)titanium, the deposition temperature was 150℃, and the pulse time was 0.2s. The inert gas was nitrogen or argon, the inert gas flow rate was 100 sccm, and the inert gas introduction time was 5s.
[0081] S6. Ozone is introduced into the reaction chamber, and the ozone reacts with the titanium source precursor to generate a TiO2 thin layer.
[0082] The ozone concentration was 80. The flow rate was 50 sccm. The high concentration of ozone reacted fully with the zirconium source precursor to obtain a TiO2 thin layer.
[0083] S7. Repeat S3-S6 for 20 cycles to obtain a 5nm thick ZrO2-TiO2 composite nano-coating.
[0084] S8. Stop the gas supply and allow the reaction chamber temperature to cool naturally to room temperature to obtain an anti-scaling reverse osmosis membrane.
[0085] Example 3 A scale-inhibiting reverse osmosis membrane includes a reverse osmosis membrane substrate, wherein a ZrO2-TiO2 composite nano-coating is attached to the surface of the reverse osmosis membrane substrate.
[0086] The ZrO2-TiO2 composite nanocoating consists of alternating ZrO2 and TiO2 layers.
[0087] The reverse osmosis membrane substrate is an aromatic polyamide reverse osmosis membrane.
[0088] The thickness of the ZrO2-TiO2 composite nanocoating is 10 nm.
[0089] The atomic ratio of Zr to Ti in the ZrO2-TiO2 composite nanocoating is 3.2:1.
[0090] The method for preparing the above-mentioned scale-inhibiting reverse osmosis membrane includes the following steps: S1. Pretreatment of the reverse osmosis membrane substrate.
[0091] The pretreatment of reverse osmosis membrane substrate includes the following steps: S11. The reverse osmosis membrane substrate is first ultrasonically cleaned with 30°C deionized water for 30 minutes.
[0092] S12. Use ethanol for ultrasonic cleaning for 15 minutes to remove organic pollutants.
[0093] S13. Place the cleaned reverse osmosis membrane substrate in a 60°C forced-air drying oven and dry for 2 hours.
[0094] S2. Place the pretreated reverse osmosis membrane substrate into the reaction chamber of the atomic layer deposition equipment, and evacuate the reaction chamber to a pressure ≤1Pa.
[0095] S3. Introduce the zirconium source precursor into the reaction chamber, perform pulse treatment, and then purge with an inert gas pulse.
[0096] The zirconium source precursor was tetra(dimethylamino)zirconium, the deposition temperature was 155℃, and the pulse time was 0.5s. The pulse treatment ensured uniform deposition of tetra(dimethylamino)zirconium on the surface of the reverse osmosis membrane substrate. The inert gas was nitrogen or argon, the inert gas flow rate was 200 sccm, and the inert gas introduction time was 8s.
[0097] S4. Ozone is introduced into the reaction chamber, and the ozone reacts with the zirconium source precursor to generate a thin layer of ZrO2.
[0098] The concentration of ozone is 100. The flow rate was 100 sccm. The high concentration of ozone reacted fully with the zirconium source precursor to obtain a ZrO2 thin layer.
[0099] S5. Introduce titanium source precursor into the reaction chamber, perform pulse treatment, and then purge with inert gas pulse.
[0100] The titanium source precursor was tetrakis(dimethylamino)titanium, the deposition temperature was 150℃, and the pulse time was 0.2s. The inert gas was nitrogen or argon, the inert gas flow rate was 100 sccm, and the inert gas introduction time was 10s.
[0101] S6. Ozone is introduced into the reaction chamber, and the ozone reacts with the titanium source precursor to generate a TiO2 thin layer.
[0102] The concentration of ozone is 100. The flow rate was 100 sccm. The high concentration of ozone reacted fully with the zirconium source precursor to obtain a TiO2 thin layer.
[0103] S7. Repeat S3-S6 for 50 cycles to obtain a 10 nm thick ZrO2-TiO2 composite nano-coating.
[0104] S8. Stop the gas supply and allow the reaction chamber temperature to cool naturally to room temperature to obtain an anti-scaling reverse osmosis membrane.
[0105] Comparative Example 1 The difference between this comparative example and Example 1 is that the composite nano-coating in this example only has a ZrO2 layer. The ZrO2 thin-layer formation process and the TiO2 thin-layer formation process described in Example 1 are used to alternately deposit ZrO2 layers to obtain a ZrO2 nano-coating with a thickness of 8 nm.
[0106] Comparative Example 2 The difference between this comparative example and Example 1 is that the composite nano-coating in this example only has a TiO2 layer. The TiO2 layer is deposited alternately using the ZrO2 thin-layer formation process and the TiO2 thin-layer formation process described in Example 1 to obtain a TiO2 nano-coating with a thickness of 8 nm.
[0107] Comparative Example 3 The difference between this comparative example and Example 1 is that the ZrO2 thin-layer formation process is changed in this comparative example, the pulse time during zirconium deposition is 0.6s, and other process parameters are the same as in Example 1. The atomic ratio of Zr to Ti in the obtained composite nano-coating is 4.5:1.
[0108] The permeation flux and desalination rate of the reverse osmosis membranes prepared in Examples 1-3 and Comparative Examples 1-3 were tested. The permeation flux and desalination rate were determined according to GB / T32373-2015 "Test Methods for Reverse Osmosis Membranes". The feed solution was a 2000 ppm sodium chloride aqueous solution with a pH of 7, an operating pressure of 15.5 bar, and an operating temperature of 25°C.
[0109] After the reverse osmosis membranes prepared in Examples 1-3 and Comparative Examples 1-3 were continuously operated in a brine solution for 100 hours, the membranes were dried to constant weight. The amount of contaminant deposited was obtained by measuring the mass difference of the reverse osmosis membranes before and after operation. The brine solution contained 20... Sodium chloride, 3 Calcium chloride, 2 Magnesium chloride, 1 The solution contained sodium bicarbonate and the remainder deionized water, with a pH of 7, and was prepared at room temperature (25°C).
[0110] Table 1 Performance of Examples 1-3 and Comparative Examples 1-3
[0111] As can be seen from Table 1, attaching a ZrO2-TiO2 composite nano-coating to the surface of the reverse osmosis membrane substrate, by controlling the thickness of the composite nano-coating and the atomic ratio of Zr to Ti, improves the hydrophilicity and oleophobicity of the reverse osmosis membrane, as well as its strong negative charge, effectively improving the flux and scale inhibition effect of the reverse osmosis membrane.
[0112] Therefore, the scale-inhibiting reverse osmosis membrane and its preparation method described in this invention can solve the problem of poor scale inhibition effect of existing osmosis membranes.
[0113] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.
Claims
1. A scale-inhibiting reverse osmosis membrane, characterized by: The application relates to a reverse osmosis membrane substrate comprising a ZrO2-TiO2 composite nano coating attached to the surface of the reverse osmosis membrane substrate.
2. The scale-inhibiting reverse osmosis membrane according to claim 1, characterized in that: The ZrO2-TiO2 composite nano coating comprises alternating ZrO2 layers and TiO2 layers.
3. The scale-inhibiting reverse osmosis membrane according to claim 1, wherein: The reverse osmosis membrane substrate is an aromatic polyamide reverse osmosis membrane, and the thickness of the ZrO2-TiO2 composite nano coating is 5-10 nm.
4. The scale-inhibiting reverse osmosis membrane according to claim 1, wherein: The atomic ratio of Zr to Ti in the ZrO2-TiO2 composite nano coating is 2.5-3.5:
1.
5. The scale-inhibiting reverse osmosis membrane according to claim 1, wherein: The reverse osmosis membrane containing the ZrO2-TiO2 composite nano coating has a contact angle with water of ≤15° and a contact angle with oil of ≥150°, and the surface of the reverse osmosis membrane has a zeta potential of -30 mV±5 mV. -30 mV±5 mV.
6. A method of making a scale-inhibiting reverse osmosis membrane according to any one of claims 1-5, characterized in that, The application further relates to a method for preparing the reverse osmosis membrane substrate, comprising the following steps: S1, pretreating the reverse osmosis membrane substrate; S2, placing the pretreated reverse osmosis membrane substrate into a reaction cavity of an atomic layer deposition device, and vacuumizing the reaction cavity to a pressure of less than or equal to 1 Pa; S3, introducing a zirconium source precursor into the reaction cavity, pulse processing, and then introducing an inert gas to perform pulse purging; S4, introducing ozone into the reaction cavity, and allowing the ozone to react with the zirconium source precursor to generate a ZrO2 thin layer; S5, introducing a titanium source precursor into the reaction cavity, pulse processing, and then introducing an inert gas to perform pulse purging; S6, introducing ozone into the reaction cavity, and allowing the ozone to react with the titanium source precursor to generate a TiO2 thin layer; S7, repeating S3-S6, and cyclically depositing 20-50 times to obtain the ZrO2-TiO2 composite nano coating; S8, stopping the gas introduction, and naturally cooling the reaction cavity to room temperature to obtain the anti-fouling reverse osmosis membrane.
7. The method of claim 6, wherein the anti-scaling reverse osmosis membrane is prepared by the steps of: In S1, the pretreatment of the reverse osmosis membrane substrate comprises the following steps: S11, first performing ultrasonic cleaning on the reverse osmosis membrane substrate with deionized water for 20-30 minutes, and the temperature of the deionized water is 30-40 DEG C; S12, performing ultrasonic cleaning with ethanol for 10-15 minutes; S13, placing the cleaned reverse osmosis membrane substrate into a blast drying oven at 60-80 DEG C and drying for 1-2 hours.
8. The method of claim 6, wherein the method further comprises: In S3, the zirconium source precursor is tetrakis(dimethylamino)zirconium, the deposition temperature is 150 DEG C + / - 5 DEG C, the pulse time is 0.1-0.5 s, the inert gas is nitrogen or argon, the inert gas flow is 100-200 sccm, and the inert gas introduction time is 5-10 s.
9. The method of claim 6, wherein the method further comprises: The concentration of ozone in S4 and S6 is 80 -100 , and the flow rate is 50-100 sccm.
10. The method of claim 6, wherein the method further comprises: In S5, the titanium source precursor is tetrakis(dimethylamino) titanium, the deposition temperature is 150 DEG C + / - 5 DEG C, the pulse time is 0.1-0.5 s, the inert gas is nitrogen or argon, the inert gas flow is 100-200 sccm, and the inert gas introduction time is 5-10 s.