Zeolite-based composite membrane for seawater desalination

Abstract

The utility model belongs to the technical field of seawater desalination, and particularly relates to a zeolite-based composite membrane for seawater desalination, which comprises a support layer, a composite membrane layer and a surface layer, the supporting layer is made of a polysulfone material and has a porous structure, and the aperture range is 0.1-10 microns; the composite membrane layer is formed by uniformly dispersing modified zeolite particles in a polyamide polymer matrix, and the particle size of the modified zeolite particles is 50-500 nanometers; and the surface layer is a polyamide layer with the thickness of 0.1-1 micron and completely covers the composite film layer. According to the zeolite-based composite membrane disclosed by the utility model, the zeolite is combined with the polyamide polymer, so that the composite membrane not only inherits the high separation performance of the zeolite, but also obviously improves the overall performance of the membrane by virtue of the mechanical strength and chemical stability of the polymer matrix.

Description

TECHNICAL FIELD

[0001] The utility model belongs to sea water desalination technical field, especially relate to a zeolite base composite membrane for sea water desalination. BACKGROUND

[0002] With the increasingly serious problem of global water resource shortage, sea water desalination as an effective solution has been widely concerned. At present, the commonly used sea water desalination methods mainly include distillation method, reverse osmosis method, electrodialysis method etc. Although the distillation method is mature in technology, it has extremely high energy consumption, large equipment investment and high operation cost, and the equipment corrosion problem is serious in high temperature environment. The reverse osmosis method has the advantages of simple equipment and easy maintenance, but the reverse osmosis membrane has problems of easy pollution, short service life and weak pressure resistance. The electrodialysis method has high requirements for pretreatment, which easily leads to membrane stack blockage, scaling and corrosion, and a large amount of electric energy is consumed. Therefore, there is an urgent need for a sea water desalination membrane with high efficiency, low energy consumption, anti-pollution and corrosion resistance. SUMMARY

[0003] In order to overcome the deficiencies of the prior art, the utility model provides a zeolite base composite membrane for sea water desalination to solve the problems in the above background art.

[0004] The utility model solves its technical problem adopts the technical scheme: provide a kind of zeolite base composite membrane for sea water desalination, including support layer, composite membrane layer and surface layer;The support layer is made of polysulfone material, with porous structure, pore size range is 0.1-10 microns;The composite membrane layer is made of modified zeolite particles uniformly dispersed in polyamide polymer matrix, wherein the particle size of modified zeolite particle is 50-500 nanometers;The surface layer is a layer of polyamide layer with thickness of 0.1-1 microns, completely covers composite membrane layer.

[0005] Further, the zeolite particles are treated by silane coupling agent, with amino or epoxy group reactive groups on the surface, and are combined with polyamide matrix by covalent bond.

[0006] Further, the composite membrane layer forms three-dimensional crosslinked network structure by interfacial polymerization method, and the zeolite particles are embedded in the crosslinked network, and the zeolite particles account for 10%-30% of the total mass of the composite membrane layer.

[0007] Further, the porosity of the support layer is 40%-70%, and the surface roughness Ra thereof is less than or equal to 0.5 microns, so as to enhance the adhesion of the composite membrane layer.

[0008] Further, the surface layer also uniformly disperses nano titanium dioxide particles therein, and the content of the nano titanium dioxide particles is 0.5%-5wt%, for improving the ultraviolet resistance and anti-pollution performance of the membrane.

[0009] Further, a transition layer is arranged between the composite membrane layer and the surface layer, the transition layer is a blend of polyamide and polyvinyl alcohol, and has a thickness of 50-200 nanometers, for relieving stress between layers and improving interface stability.

[0010] The utility model discloses the beneficial effect is:

[0011] (1) Because zeolite has uniform micropore distribution and larger specific surface area, can provide efficient transport channel for water molecules, effectively intercept the salt and other impurities in seawater. This unique pore structure makes the composite membrane show excellent desalination performance in the process of seawater desalination, significantly improves the recovery rate and water quality of fresh water. By adjusting the type and amount of zeolite, the pore size of the membrane can be further optimized to better meet the needs of seawater desalination.

[0012] (2) By combining zeolite with polyamide polymer, the composite membrane not only inherits the high separation performance of zeolite, but also takes advantage of the mechanical strength and chemical stability of the polymer matrix, significantly improving the overall performance of the membrane. The crosslinking reaction of polyamide makes the zeolite particles firmly embedded in the polymer network, forming a dense desalination functional layer, thereby enhancing the compression resistance and durability of the membrane. This structural design enables the composite membrane to operate stably in complex seawater environment for a long time, reducing the frequency of membrane damage and replacement.

[0013] (3) The porous structure of zeolite provides abundant adsorption sites, which can effectively adsorb calcium, magnesium and other ions in seawater, reducing the deposition of these ions on the membrane surface. At the same time, the protective effect of the polymer matrix further reduces the risk of membrane surface pollution. By surface modification of zeolite with silane coupling agent, the interfacial compatibility between zeolite and polymer is enhanced, making the membrane surface more uniform and dense, thereby further improving the anti-pollution ability. This anti-pollution performance not only prolongs the service life of the membrane, but also reduces the cleaning and maintenance cost.

[0014] (4) By adjusting the type, amount of zeolite and the crosslinking degree of polymer, the pore size and hydrophilic / hydrophobic property of the composite membrane can be accurately controlled. The optimized pore size distribution enables water molecules to pass through the membrane more efficiently, while effectively retaining salt and other impurities, improving the separation efficiency of the membrane. In addition, appropriate hydrophilic / hydrophobic property helps to reduce the formation of water droplets on the membrane surface, further improving the transmission efficiency of water molecules and reducing energy consumption.

[0015] (5) The high-efficiency ion sieve performance of zeolite and the optimized design of polymer matrix enable the composite membrane to achieve efficient seawater desalination at low operating pressure. Compared with traditional reverse osmosis membranes, this low-energy consumption feature not only reduces operating costs, but also reduces dependence on energy, with significant economic and environmental benefits. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 Figure 1 is a structural schematic diagram of a zeolite-based composite membrane for seawater desalination according to the present application;

[0017] Figure 2 Figure 2 is another structural schematic diagram of a zeolite-based composite membrane for seawater desalination according to the present application;

[0018] The reference signs are: 1, support layer; 2, composite membrane layer; 3, transition layer; 4, surface layer. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. It can be understood that the specific embodiments described herein are only used to explain the present application, rather than limit the present application. In addition, it should be noted that, for the convenience of description, only the parts related to the present application are shown in the drawings, rather than all the structures.

[0020] Embodiment:

[0021] Preparation of the support layer: a porous support layer is prepared by phase inversion method using polysulfone PSF material. Polysulfone is dissolved in N-methyl pyrrolidone NMP to form a solution with a mass fraction of 15%. The solution is uniformly coated on a glass plate and immersed in deionized water for phase separation to form a porous structure. The pore size of the support layer ranges from 0.1 to 10 μm, the porosity is 50%, and the surface roughness Ra is 0.3 μm. The prepared support layer is dried at 60°C for 12 hours for standby.

[0022] Surface modification of zeolite particles: take zeolite particles with a particle size of 200 nanometers, add a 5% mass fraction of silane coupling agent ethanol solution, stir for 2 hours, so that the zeolite particle surface has amino reactive groups. The modified zeolite particles are washed with deionized water for 3 times to remove unreacted silane coupling agent, and then dried at 80°C for 6 hours.

[0023] Preparation of the composite membrane layer: the modified zeolite particles are uniformly dispersed in the polyamide precursor solution, and the zeolite particles account for 20% of the total mass of the composite membrane layer. The support layer is immersed in the above solution, and after taking out, an interfacial polymerization reaction is carried out with the triformyl chloride solution to form a three-dimensional cross-linked network structure. The reaction time is 1 minute and the reaction temperature is 25°C. The composite membrane layer is dried at 60°C for 2 hours to form a dense desalination functional layer.

[0024] Preparation of the surface layer: a layer of polyamide solution with a thickness of 0.5 microns is coated on the surface of the composite membrane layer, wherein 2wt% of nano-titanium dioxide particles are uniformly dispersed. After coating, dry at 80°C for 1 hour to form a surface layer.

[0025] Preparation of the transition layer: a transition layer with a thickness of 100 nm is coated between the composite membrane layer and the surface layer, and the transition layer is formed by blending polyamide and polyvinyl alcohol (mass ratio 1:1). After coating, dry at 60 DEG C for 1 hour to form a transition layer. As shown in Figure 1 and Figure 2 The structure diagram of the zeolite-based composite membrane for seawater desalination is shown.

[0026] The zeolite-based composite membrane of the utility model can realize efficient, low-energy-consumption, anti-pollution and corrosion-resistant seawater desalination effect by optimizing the structure design of the support layer, the composite membrane layer and the surface layer, combining the surface modification of the zeolite particles and the functional additives. The preparation method is simple, suitable for large-scale production and has wide application prospect.

[0027] The above only describes the preferred embodiments of the utility model and is not used for limiting the utility model. For the person skilled in the art, the utility model can have various changes and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the utility model should be included in the protection scope of the utility model.

Claims

1. A zeolite-based composite membrane for seawater desalination, characterized by: The composite membrane comprises a support layer, a composite membrane layer and a surface layer; the support layer is made of polysulfone material and has a porous structure with a pore size ranging from 0.1 to 10 microns; the composite membrane layer is composed of modified zeolite particles uniformly dispersed in a polyamide polymer matrix, wherein the particle size of the modified zeolite particles ranges from 50 to 500 nanometers; and the surface layer is a polyamide layer with a thickness of 0.1 to 1 micron, which completely covers the composite membrane layer.

2. A zeolite-based composite membrane for seawater desalination according to claim 1, characterized by: The zeolite particles are treated with a silane coupling agent, and have amino or epoxy reactive groups on the surface to covalently bond with the polyamide matrix.

3. A zeolite-based composite membrane for seawater desalination according to claim 1, characterized by: The composite membrane layer forms a three-dimensional crosslinked network structure by interfacial polymerization, and the zeolite particles are embedded in the crosslinked network, and the zeolite particles account for 10% to 30% of the total mass of the composite membrane layer.

4. The zeolite-based composite membrane for seawater desalination according to claim 1, characterized in that: The porosity of the support layer is 40% to 70%, and the surface roughness Ra is less than or equal to 0.5 microns.

5. The zeolite-based composite membrane for seawater desalination according to claim 1, characterized in that: The surface layer also uniformly disperses nano-titanium dioxide particles, and the content of the nano-titanium dioxide particles is 0.5% to 5% by weight.

6. The zeolite-based composite membrane for seawater desalination according to claim 1, characterized in that: A transition layer is provided between the composite membrane layer and the surface layer, and the transition layer is a blend of polyamide and polyvinyl alcohol with a thickness of 50 to 200 nanometers.

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