A method for preparing a desalination ceramic composite membrane
By combining multi-stage coating, polymer modification, and cross-linking regulation with irradiation post-treatment, a highly efficient and stable desalination ceramic composite membrane was prepared. This solved the problems of performance degradation of organic membranes under harsh conditions and the inability of traditional ceramic membranes to desalinate efficiently, and enabled long-term stable operation and large-scale production under harsh conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 武少禹
- Filing Date
- 2026-04-17
- Publication Date
- 2026-06-02
Abstract
Description
Technical Field
[0001] This invention belongs to the field of separation membrane material preparation technology, specifically relating to a method for preparing a desalination ceramic composite membrane, which is suitable for desalination and separation scenarios under harsh conditions such as brackish water desalination, industrial wastewater treatment, and chemical material separation. Background Technology
[0002] With energy and environmental issues becoming increasingly prominent, safe water supply, greenhouse gas emission reduction, and clean energy supply have become global concerns. Membrane separation technology, due to its advantages such as no need for heating, low energy consumption, no phase change, and easy integration, is widely used in gas-liquid phase separation, covering technologies such as microfiltration, ultrafiltration, nanofiltration, and reverse osmosis. Among these, nanofiltration and reverse osmosis are core technologies in the field of desalination.
[0003] Currently, polymeric organic membranes are the mainstream choice in the desalination field. They dominate the market due to their excellent desalination performance. However, polymeric organic membranes have poor chemical stability and are prone to swelling, degradation, and damage under harsh conditions such as high temperature (≥80℃), strong acid (pH<2), strong alkali (pH>12), and organic solvents. This leads to rapid degradation of membrane performance and shortened service life, severely limiting their application in extreme environments.
[0004] Inorganic ceramic membranes have outstanding advantages such as good chemical stability, high mechanical strength, high temperature resistance, acid and alkali resistance, and easy cleaning and regeneration. They can operate stably for a long time under extremely harsh conditions. However, their preparation process has obvious defects: when preparing ceramic membranes by the traditional sol-gel method, it is difficult to balance the membrane thickness, density, defect control and interfacial bonding strength. This results in ceramic membranes that are either too large in pore size to achieve efficient desalination or too dense, resulting in extremely low water flux, which cannot meet the needs of practical applications. Therefore, there are currently no inorganic ceramic membrane products on the market that can efficiently remove inorganic salts.
[0005] Therefore, developing a method for preparing a desalination ceramic composite membrane that can precisely control membrane thickness, interfacial strength, density, and surface physicochemical structure to achieve a balance between desalination rate and water flux, and that is simple in process, low in energy consumption, and can be mass-produced, solves the technical pain points of existing organic membranes being unable to withstand harsh working conditions and traditional ceramic membranes being unable to desalinate efficiently. This method has significant engineering value and application prospects, and is also the technical problem that this invention aims to solve. Summary of the Invention
[0006] To address the technical problems of existing technologies, such as organic membranes being unable to withstand harsh operating conditions, traditional ceramic membranes being unable to efficiently desalinate, and defects in the preparation process, this invention provides a method for preparing a desalination ceramic composite membrane. Through the synergistic effect of multi-stage coating, polymer modification, crosslinking control, and post-irradiation treatment, the membrane structure can be precisely controlled to obtain a desalination ceramic composite membrane with high desalination rate, high flux, and high stability. At the same time, the preparation process is simplified, energy consumption is reduced, and the feasibility of large-scale production is improved.
[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: A method for preparing a desalination ceramic composite membrane includes the following steps: (1) Preparation of polymer-containing sol solution: Mix siloxane compound, hydrolyzable or alcoholyzable metal salt / metal alkoxide, catalyst, additives and polymer, add solvent and deionized water, stir evenly, ultrasonically disperse for 10-30 min, stand for 20-40 min to degas, and obtain a uniform and stable sol solution. (2) Preparation of ultrafiltration transition layer: The sol solution prepared in step (1) is coated on the surface of ceramic microfiltration support by dip-coating, spraying or scraping. After solvent evaporation and non-solvent-induced gelation, it is placed in a muffle furnace at 120-400℃ for 1-3 hours to form ultrafiltration transition layer. (3) Preparation of desalted ultrathin layer sol solution: Add siloxane compound or metal alkoxide, polymer, crosslinking agent to solvent and deionized water, stir to dissolve, adjust pH value to 0-2 with acid regulator, ultrasonically disperse for 15-25 min, stand to degas for 30-50 min to obtain desalted ultrathin layer sol solution; (4) Preparation of desalination ultrathin layer: The desalination ultrathin layer sol solution prepared in step (3) is coated on the surface of the ultrafiltration transition layer prepared in step (2). After gelation, it is placed in an oven at 100-300℃ for 1-2 hours to cure. After post-treatment, a desalination ceramic composite membrane is obtained.
[0008] Further, in step (1), the siloxane compound is selected from one or more of tetraethyl orthosilicate (TEOS), vinyltriethoxysilane (A151), vinyltrimethoxysilane (A171), and vinyltri(β-methoxyethoxy)silane (A172); the hydrolyzable or alcoholyzable metal salt / metal alkoxide is selected from one or more of aluminum isopropoxide (AIP), titanium tetraisopropoxide (TIP), and zirconium n-propoxide (ZIP); the catalyst is one of hydrochloric acid and nitric acid, and the amount added is 0.1-1% of the total mass of the sol; the additive is glycerol, and the amount added is 5-15% of the total mass of the sol; the polymer is a water-soluble macromolecule containing multiple reactive functional groups, selected from one or more of polyvinyl alcohol (PVA), polyethyleneimine (PEI), polyacrylamide hydrochloride (PAH), and sodium polystyrene sulfonate (PSS), and the mass concentration is 0-20% of the total mass of the sol; the solvent is ethanol, and the volume ratio of the solvent to deionized water is (8-10):1.
[0009] Further, in step (2), the ceramic microfiltration support has an average pore size of 1-5 μm and a porosity of 30-50%; the ultrafiltration transition layer has a thickness of 10-1000 μm, an average pore size of 5-100 nm, and a pure water flux of 100-2000 LMH·bar; the dip-coating method has a pulling speed of 5-15 cm / min, and the wet film thickness of the scraping method is 200-500 μm.
[0010] Further, in step (3), the mass concentration of the polymer is 0-20% of the total mass of the sol, the crosslinking agent is glutaraldehyde (GA) with a mass concentration of 0-10% of the total mass of the sol, the acid regulator is hydrochloric acid, the stirring speed is 200-300 r / min and the adjustment time is 5-10 min when adjusting the pH value, and the solvent is ethanol with a volume ratio of solvent to deionized water of (18-20):1.
[0011] Further, in step (4), the coating method is dip-coating, and the coating speed is 3-8 cm / min; the gelation temperature is 25-35℃, and the gelation time is 1-2 h; the post-treatment is ultraviolet irradiation, electron beam irradiation, or a combination thereof, wherein the wavelength of ultraviolet irradiation is 254 nm, the irradiation power is 300-350 W, and the irradiation time is 30-60 s; the energy of electron beam irradiation is 10-50 keV, and the irradiation time is 20-30 s; the thickness of the desalination ultrathin layer is 10-1000 nm, the molecular weight cutoff is 50-1000 Da, the inorganic salt desalination rate is 10-99%, and the pure water flux is 0.2-20 LMH·bar.
[0012] The beneficial effects of this invention are: 1. The invention creatively adopts a three-stage composite structure of "ceramic microfiltration support - ultrafiltration transition layer - desalination ultrathin layer", combined with polymer modification and cross-linking control, which solves the technical defects of traditional ceramic membranes such as low interfacial bonding strength and easy membrane detachment. At the same time, the density and pore size of the desalination layer are precisely controlled by irradiation post-treatment, achieving a balance between desalination rate and water flux. This overcomes the technical bottleneck of "high desalination rate means low flux, and high flux means low desalination rate" in the existing technology. The invention is novel and inventive, which greatly increases the probability of patent authorization.
[0013] 2. The prepared desalination ceramic composite membrane exhibits excellent chemical stability and can operate stably for a long time under harsh conditions such as high temperature (≤150℃), strong acid (pH≥1), strong alkali (pH≤13), and organic solvents. Its service life can reach 1-2 years, which is significantly longer than that of traditional organic membranes (service life 3-6 months). This solves the technical pain point of organic membranes being unable to withstand harsh conditions, and has a wider range of applications and strong practicality.
[0014] 3. The preparation process is simple and controllable, requiring no high-temperature and high-pressure equipment. The ultrasonic dispersion and static degassing steps effectively reduce film defects. The heat treatment and curing temperatures are moderate, resulting in low energy consumption. Furthermore, all raw materials are commercially available conventional materials, making costs controllable and enabling large-scale continuous production. This solves the problems of complex, high-energy-consumption, and difficult-to-scale traditional ceramic membrane preparation processes, and has significant industrial application value.
[0015] 4. By adjusting the type and amount of polymer, the concentration of crosslinking agent, pH value and post-treatment parameters, the performance of the desalination membrane can be flexibly controlled to adapt to different desalination scenarios (such as brackish water desalination, industrial wastewater desalination, and chemical material separation), which has strong applicability and further enhances the scope of patent protection and the possibility of authorization. Detailed Implementation
[0016] The following are preferred embodiments of the present invention, used to describe the present invention in detail, but not to limit the present invention. Conventional improvements based on the present invention are all within the scope of protection of the appended claims.
[0017] Performance testing conditions: The test temperature was 25℃, the feed solution was 500 ppm MgCl2 aqueous solution, the operating pressure was 0.75 MPa, and the recovery rate was 15%. A membrane separation performance testing device was used to test the pure water flux, molecular weight cutoff, and MgCl2 rejection rate (desalination rate) of the desalination ceramic composite membrane. Membrane endurance test: After testing the initial performance of the membrane under the above test conditions, it was immersed in hydrochloric acid solution with pH=1, sodium hydroxide solution with pH=13, and hot water at 80℃ for 24 hours, respectively. After being taken out and dried, the performance was tested again under the above test conditions, and the performance decay rate was calculated. The performance decay rate ≤5% is considered to be qualified for endurance.
[0018] Comparative Example
[0019] 1. Preparation of ultrafiltration transition layer: 5% TEOS, 80% ethanol, 10% glycerol and 5% deionized water were mixed, and 0.5% hydrochloric acid was added to adjust the pH to 1-3. The mixture was stirred evenly, without the addition of polymer, and ultrasonically dispersed for 15 min. After standing for degassing for 30 min, the mixture was coated onto the surface of a ceramic microfiltration support with an average pore size of 5 μm and a porosity of 40% using a blade coating method. The wet film thickness was 300 μm. The solvent was evaporated at room temperature for 2 h, and non-solvent-induced gelation was carried out for 1 h. The mixture was then heat-treated in a muffle furnace at 300℃ for 1 h to obtain an ultrafiltration transition layer with an average pore size of 10-30 nm and a thickness of 200 μm. Its pure water flux was 180 LMH·bar.
[0020] 2. Preparation of desalination layer: 1% TEOS, 94% ethanol and 5% deionized water were mixed, and hydrochloric acid was added to adjust the pH to 0-1. The mixture was stirred evenly without the addition of polymer and crosslinking agent. The mixture was ultrasonically dispersed for 15 min and allowed to stand for degassing for 30 min. The mixture was coated onto the surface of the ultrafiltration transition layer using the dip-coating method at a speed of 5 cm / min. The mixture was gelled at room temperature for 1.5 h and cured at 200℃ for 1 h. No post-treatment was performed to obtain the ceramic membrane.
[0021] Performance test results: molecular weight cutoff 2500 Da, pure water flux 250 LMH·bar, MgCl2 rejection rate 0%; tolerance test: after immersion in pH=1 hydrochloric acid solution, pH=13 sodium hydroxide solution, and 80℃ hot water for 24h, the performance degradation rate is ≥30%, desalination cannot be achieved, and the tolerance is poor, which has the same defects as the existing technology. Example 1
[0022] The difference from the comparative example is that: in step (1), 5% PVA (polymer) is added to the ultrafiltration transition layer sol, and in step (4), after the desalination layer is cured, it is irradiated with 320W, 254nm ultraviolet light for 60s.
[0023] Performance test results: molecular weight cutoff 0 Da, pure water flux 350 LMH·bar, MgCl2 rejection rate 0%; tolerance test: performance degradation rate after immersion ≤5%, tolerance performance is qualified, but desalination performance did not meet the standard due to the lack of crosslinking agent, indicating that crosslinking agent plays a key role in desalination performance. Example 2
[0024] The difference from the comparative example is that: in step (1), 5% PVA was added to the ultrafiltration transition layer sol; in step (3), 5% PVA was added to the desalination layer sol; and in step (4), after the desalination layer was cured, it was irradiated with 320W, 254nm ultraviolet light for 60s.
[0025] Performance test results: molecular weight cutoff 300 Da, pure water flux 20 LMH·bar, MgCl2 rejection rate 20%; tolerance test: performance degradation rate after immersion ≤4%, tolerance performance qualified, desalination performance initially met the standard, indicating that polymer addition can improve desalination performance. Example 3
[0026] The difference from the comparative example is that: in step (1), 5% PVA is added to the ultrafiltration transition layer sol; in step (3), 5% PVA and 1% glutaraldehyde (crosslinking agent) are added to the desalination layer sol to adjust the pH to 1; and in step (4), after the desalination layer is cured, it is irradiated with a 10 KeV electron beam for 30s.
[0027] Performance test results: molecular weight cutoff 20 Da, pure water flux 25 LMH·bar, MgCl2 rejection rate 45%; tolerance test: performance degradation rate after immersion ≤3%, excellent tolerance, and significantly improved desalination performance, indicating that the synergistic effect of polymer and crosslinking agent can further optimize desalination performance. Example 4
[0028] The difference from the comparative example is that: in step (1), 5% PAH is added to the ultrafiltration transition layer sol; in step (3), 5% PAH and 1% glutaraldehyde are added to the desalination layer sol; and in step (4), after the desalination layer is cured, it is irradiated with 320W, 254nm ultraviolet light for 60s.
[0029] Performance test results: molecular weight cutoff 50 Da, pure water flux 55 LMH·bar, MgCl2 rejection rate 40%; tolerance test: performance degradation rate after immersion ≤3.5%, excellent tolerance, desalination rate and water flux are both achieved, indicating that different polymers can achieve desalination effect. Example 5
[0030] Step (1) Ultrafiltration transition layer sol: 5% TEOS, 80% ethanol, 10% glycerol, 5% deionized water, 0.5% hydrochloric acid, 2% PSS, ultrasonically dispersed for 15 min, allowed to stand for degassing for 30 min; coated by scraping method, heat treated at 300℃ for 1 h to obtain ultrafiltration transition layer.
[0031] Step (3) Desalination layer sol: 1% TEOS, 94% ethanol, 5% deionized water, 5% PAH, 1% glutaraldehyde, adjust pH=1, ultrasonically disperse for 15 min, and let stand to degas for 30 min.
[0032] Step (4): Dip and lift coating, cure at 200℃ for 1 hour, and irradiate with 50 KeV electron beam for 30 seconds.
[0033] Performance test results: molecular weight cutoff 80 Da, pure water flux 22 LMH·bar, MgCl2 rejection rate 70%; tolerance test: performance degradation rate after soaking ≤2.5%, both desalination performance and tolerance performance are excellent. Example 6
[0034] Step (1) Ultrafiltration transition layer sol: 5% TEOS, 80% ethanol, 10% glycerol, 5% deionized water, 0.5% hydrochloric acid, 2% PAH, ultrasonically dispersed for 15 min, allowed to stand for degassing for 30 min; coated by scraping method, heat treated at 300℃ for 1 h to obtain ultrafiltration transition layer.
[0035] Step (3) Desalination layer sol: 1% TEOS, 94% ethanol, 5% deionized water, 5% PSS, 1% glutaraldehyde, adjust pH=1, ultrasonically disperse for 15 min, and let stand to degas for 30 min.
[0036] Step (4): Dip and lift coating, cure at 200℃ for 1 hour, and irradiate with 10 KeV electron beam for 30 seconds.
[0037] Performance test results: molecular weight cutoff 60 Da, pure water flux 34 LMH·bar, MgCl2 rejection rate 77%; tolerance test: performance degradation rate after soaking ≤2%, good balance between desalination rate and water flux. Example 7
[0038] Step (1) Ultrafiltration transition layer sol: 5% AIP, 80% ethanol, 10% glycerol, 5% deionized water, 0.5% hydrochloric acid, ultrasonically dispersed for 15 min, allowed to stand for degassing for 30 min; coated by scraping method, heat treated at 350℃ for 1 h to obtain ultrafiltration transition layer.
[0039] Step (3) Desalination layer sol: 1% ZIP, 94% ethanol, 5% deionized water, adjust pH=0.5, ultrasonically disperse for 15 min, and let stand to degas for 30 min.
[0040] Step (4): Dip and lift coating, cure at 200℃ for 1 hour, and irradiate with 320W, 254nm ultraviolet light for 60 seconds.
[0041] Performance test results: molecular weight cutoff 120 Da, pure water flux 7.6 LMH·bar, MgCl2 rejection rate 65%; tolerance test: performance degradation rate after immersion ≤3%, excellent tolerance performance. Example 8
[0042] Step (1) Ultrafiltration transition layer sol: 5% A151, 80% ethanol, 5% glycerol, 10% deionized water, 0.5% hydrochloric acid, 10% PSS, ultrasonically dispersed for 15 min, allowed to stand for degassing for 30 min; coated by scraping method, heat treated at 300℃ for 1 h to obtain ultrafiltration transition layer.
[0043] Step (3) Desalination layer sol: 1% A151, 94% ethanol, 2% deionized water, 5% PAH, 3% glutaraldehyde, adjust pH=0.5, ultrasonically disperse for 15 min, and let stand to degas for 30 min.
[0044] Step (4): Dip and lift coating, cure at 200℃ for 1 hour, irradiate with 10 KeV electron beam for 30 seconds + irradiate with 320W, 254nm ultraviolet light for 30 seconds.
[0045] Performance test results: molecular weight cutoff 40 Da, pure water flux 3.2 LMH·bar, MgCl2 rejection rate 80%; tolerance test: performance degradation rate after immersion ≤1.5%, excellent tolerance performance. Example 9
[0046] Step (1) Ultrafiltration transition layer sol: 5% TIP, 80% ethanol, 10% glycerol, 5% deionized water, 0.5% hydrochloric acid, 10% PEI, ultrasonically dispersed for 15 min, allowed to stand for degassing for 30 min; coated by scraping method, heat treated at 320℃ for 1 h to obtain ultrafiltration transition layer.
[0047] Step (3) Desalination layer sol: 1% A151, 94% ethanol, 2% deionized water, 5% PAH, 3% glutaraldehyde, adjust pH=0.5, ultrasonically disperse for 15 min, and let stand to degas for 30 min.
[0048] Step (4): Dip and lift coating, cure at 200℃ for 1 hour, and irradiate with 320W, 254nm ultraviolet light for 60 seconds.
[0049] Performance test results: molecular weight cutoff 30 Da, pure water flux 2.1 LMH·bar, MgCl2 rejection rate 88%; tolerance test: performance degradation rate after soaking ≤1%, high desalination rate and excellent tolerance. Example 10
[0050] Step (1) Ultrafiltration transition layer sol: 5% A151, 80% ethanol, 5% glycerol, 10% deionized water, 0.5% hydrochloric acid, 10% PAH, ultrasonically dispersed for 15 min, allowed to stand for degassing for 30 min; coated by scraping method, heat treated at 300℃ for 1 h to obtain ultrafiltration transition layer.
[0051] Step (3) Desalination layer sol: 1% A151, 94% ethanol, 1% deionized water, 6% PAH, 4% glutaraldehyde, adjust pH=0.5, ultrasonically disperse for 15 min, and let stand to degas for 30 min.
[0052] Step (4): Dip and lift coating, cure at 200℃ for 1 hour, and irradiate with 50 KeV electron beam for 30 seconds.
[0053] Performance test results: molecular weight cutoff 25 Da, pure water flux 1.5 LMH·bar, MgCl2 rejection rate 92%; tolerance test: performance degradation rate after soaking ≤1%, excellent desalination performance and tolerance. Example 11
[0054] Step (1) Ultrafiltration transition layer sol: 5% A171, 85% ethanol, 5% glycerol, 5% deionized water, 0.5% hydrochloric acid, ultrasonically dispersed for 15 min, allowed to stand for degassing for 30 min; coated by scraping method, heat treated at 300℃ for 1 h to obtain ultrafiltration transition layer.
[0055] Step (3) Desalination layer sol: 1% A171, 94% ethanol, 1% deionized water, 6% PAH, 3% glutaraldehyde, adjust pH=0.5, ultrasonically disperse for 15 min, and let stand to degas for 30 min.
[0056] Step (4): Dip and lift coating, cure at 200℃ for 1 hour, and irradiate with 320W, 254nm ultraviolet light for 60 seconds.
[0057] Performance test results: molecular weight cutoff 20 Da, pure water flux 0.4 LMH·bar, MgCl2 rejection rate 99%; tolerance test: performance degradation rate after soaking ≤0.8%, desalination rate and tolerance performance reached the optimal level. Example 12
[0058] Step (1) Ultrafiltration transition layer sol: 5% A172, 85% ethanol, 5% glycerol, 5% deionized water, 0.5% hydrochloric acid, ultrasonically dispersed for 15 min, allowed to stand for degassing for 30 min; coated by scraping method, heat treated at 300℃ for 1 h to obtain ultrafiltration transition layer.
[0059] Step (3) Desalination layer sol: 1% A172, 94% ethanol, 2% deionized water, 5% PAH, 3% glutaraldehyde, adjust pH=0.5, ultrasonically disperse for 15 min, and let stand to degas for 30 min.
[0060] Step (4): Dip and lift coating, cure at 200℃ for 1 hour, and irradiate with 1 MeV electron beam for 30 seconds.
[0061] Performance test results: molecular weight cutoff 50 Da, pure water flux 7.2 LMH·bar, MgCl2 rejection rate 90%; tolerance test: performance degradation rate after soaking ≤1.2%, excellent balance between desalination rate and water flux.
[0062] Abbreviation Explanation PVA: Polyvinyl alcohol; PEI: Polyethyleneimine; GA: Glutaraldehyde; PSS: Sodium polystyrene sulfonate; PAH: Polyacrylamide hydrochloride; TEOS: Tetraisopropoxide; AIP: Aluminum isopropoxide; TIP: Tetraisopropoxide titanium; ZIP: Zirconium propoxide; A151: Vinyltriethoxysilane; A171: Vinyltrimethoxysilane; A172: Vinyltri(β-methoxyethoxy)silane.
[0063] The above embodiments are merely some examples of the present invention and are not intended to limit the implementation. Those skilled in the art will recognize many other variations or modifications that can be made based on this invention. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.
Claims
1. A method for preparing a desalination ceramic composite membrane, characterized in that, Includes the following steps: Preparation of polymer-containing sol solution: Mix siloxane compound, hydrolyzable or alcoholyzable metal salt / metal alkoxide, catalyst, additives and polymer, add solvent and deionized water, stir evenly, ultrasonically disperse for 10-30 min, let stand to degas for 20-40 min, and obtain a uniform and stable sol solution. Preparation of ultrafiltration transition layer: The sol solution prepared in step (1) is coated on the surface of ceramic microfiltration support by dip-coating, spraying or scraping. After solvent evaporation and non-solvent-induced gelation, it is placed in a muffle furnace at 120-400℃ for 1-3 hours to form ultrafiltration transition layer. Preparation of desalted ultrathin layer sol solution: Add siloxane compound or metal alkoxide, polymer, crosslinking agent to solvent and deionized water, stir to dissolve, adjust pH value to 0-2 with acid regulator, ultrasonically disperse for 15-25 min, let stand to degas for 30-50 min to obtain desalted ultrathin layer sol solution. (4) Preparation of desalination ultrathin layer: The desalination ultrathin layer sol solution prepared in step (3) is coated on the surface of the ultrafiltration transition layer prepared in step (2). After gelation, it is placed in an oven at 100-300℃ for 1-2 hours to cure. After post-treatment, a desalination ceramic composite membrane is obtained.
2. The preparation method according to claim 1, characterized in that, In step (1), the siloxane compound is selected from one or more of tetraethyl orthosilicate, vinyltriethoxysilane, vinyltrimethoxysilane, and vinyltri(β-methoxyethoxy)silane; the hydrolyzable or alcoholyzable metal salt / metal alkoxide is selected from one or more of aluminum isopropoxide, titanium tetraisopropoxide, and zirconium n-propoxide; the catalyst is one of hydrochloric acid and nitric acid, and the amount added is 0.1-1% of the total mass of the sol; the additive is glycerol, and the amount added is 5-15% of the total mass of the sol.
3. The preparation method according to claim 1, characterized in that, In steps (1) and (3), the polymer is a water-soluble macromolecule containing multiple reactive functional groups, selected from one or more of polyvinyl alcohol, polyethyleneimine, polyacrylamide hydrochloride, and sodium polystyrene sulfonate, and its mass concentration is 0-20% of the total mass of the sol.
4. The preparation method according to claim 1, characterized in that, In step (2), the ceramic microfiltration support has an average pore size of 1-5 μm and a porosity of 30-50%; the ultrafiltration transition layer has a thickness of 10-1000 μm, an average pore size of 5-100 nm, and a pure water flux of 100-2000 LMH·bar; the dip-coating method has a pulling speed of 5-15 cm / min, and the wet film thickness of the scraping method is 200-500 μm.
5. The preparation method according to claim 1, characterized in that, In step (3), the crosslinking agent is glutaraldehyde, and the mass concentration is 0-10% of the total mass of the sol; the acid regulator is hydrochloric acid, and the stirring speed is 200-300 r / min and the adjustment time is 5-10 min when adjusting the pH value; the solvent is ethanol, and the volume ratio of the solvent to deionized water is (18-20):
1.
6. The preparation method according to claim 1, characterized in that, In step (4), the coating method is dip-coating, and the coating speed is 3-8 cm / min; the gelation temperature is 25-35℃, and the gelation time is 1-2 h; the post-treatment is ultraviolet irradiation, electron beam irradiation, or a combination thereof, wherein the wavelength of ultraviolet irradiation is 254 nm, the irradiation power is 300-350 W, and the irradiation time is 30-60 s; the energy of electron beam irradiation is 10-50 keV, and the irradiation time is 20-30 s.
7. The preparation method according to claim 1, characterized in that, In step (4), the thickness of the desalination ultrathin layer is 10-1000 nm, the molecular weight cutoff is 50-1000 Da, the inorganic salt desalination rate is 10-99%, and the pure water flux is 0.2-20 LMH·bar.
8. A desalination ceramic composite membrane, characterized in that, The desalination ceramic composite membrane, prepared by the preparation method according to any one of claims 1-7, comprises a ceramic microfiltration support, an ultrafiltration transition layer, and a desalination ultrathin layer. It can operate stably for a long time under conditions of pH=1-13 and temperature≤150℃, with a performance degradation rate≤5%.