WO2022127635A1 - 脱硼反渗透膜及其制备方法 - Google Patents

脱硼反渗透膜及其制备方法 Download PDF

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Publication number
WO2022127635A1
WO2022127635A1 PCT/CN2021/135768 CN2021135768W WO2022127635A1 WO 2022127635 A1 WO2022127635 A1 WO 2022127635A1 CN 2021135768 W CN2021135768 W CN 2021135768W WO 2022127635 A1 WO2022127635 A1 WO 2022127635A1
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layer
solution
support layer
nano
reverse osmosis
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PCT/CN2021/135768
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English (en)
French (fr)
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杨兴胜
梁松苗
胡利杰
康燕
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沃顿科技股份有限公司
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Publication of WO2022127635A1 publication Critical patent/WO2022127635A1/zh

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
    • B01D61/02—Reverse osmosis; Hyperfiltration ; Nanofiltration
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
    • B01D67/0002—Organic membrane manufacture
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
    • B01D69/12—Composite membranes; Ultra-thin membranes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/40—Polymers of unsaturated acids or derivatives thereof, e.g. salts, amides, imides, nitriles, anhydrides, esters
    • B01D71/42—Polymers of nitriles, e.g. polyacrylonitrile
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/40—Polymers of unsaturated acids or derivatives thereof, e.g. salts, amides, imides, nitriles, anhydrides, esters
    • B01D71/42—Polymers of nitriles, e.g. polyacrylonitrile
    • B01D71/421—Polyacrylonitrile
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/56—Polyamides, e.g. polyester-amides
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
    • B01D71/06—Organic material
    • B01D71/66—Polymers having sulfur in the main chain, with or without nitrogen, oxygen or carbon only
    • B01D71/68—Polysulfones; Polyethersulfones
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F1/00—Treatment of water, waste water, or sewage
    • C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
    • C02F1/441—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis by reverse osmosis
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2101/00—Nature of the contaminant
    • C02F2101/10—Inorganic compounds
    • C—CHEMISTRY; METALLURGY
    • C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
    • C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
    • C02F2103/08—Seawater, e.g. for desalination
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
    • Y02A20/00—Water conservation; Efficient water supply; Efficient water use
    • Y02A20/124—Water desalination
    • Y02A20/131—Reverse-osmosis

Definitions

  • the present disclosure relates to a deboronation reverse osmosis membrane and a preparation method thereof, in particular to a laminated loading interface polymerization high deboronation seawater desalination membrane and a preparation method thereof, belonging to the field of water treatment.
  • Seawater desalination is one of the effective ways to solve the current crisis of freshwater resources, and the use of reverse osmosis membrane method for seawater desalination has become one of the main technologies, which is estimated to account for 44% of the world's total seawater desalination, and continues to increase year by year.
  • Aromatic polyamide composite membranes are currently the most commonly used reverse osmosis membranes, with good water flux and salt rejection, as well as wider operating temperature and pH ranges.
  • a major factor limiting the application of aromatic polyamide reverse osmosis membranes is their relatively low removal rate of uncharged small molecules, such as boric acid.
  • Boron is a trace element in seawater. It mainly exists in the form of uncharged boric acid molecules in seawater. The average concentration is 4-7mg/L, and the highest can reach 9.6mg/L. Boron content exceeding a certain limit is toxic and harmful. According to the World Health Organization (WHO) report, when the boron content in water exceeds 2.4mg/L, it will cause plant poisoning. Excessive boron will also cause dizziness, nausea and kidney failure. and other symptoms. WHO recommends that boron content in drinking water should be less than 0.5mg/L. Therefore, boron removal is an important indicator in the desalination process.
  • WHO World Health Organization
  • the boric acid in seawater (about 95%) exists in the form of molecules, so the electrostatic repulsion mechanism of the reverse osmosis membrane to remove salt ions becomes ineffective, and it cannot effectively remove uncharged boric acid like desalination.
  • the steric hindrance mechanism removes boron.
  • the size of the uncharged boric acid molecule is 0.275nm, and the Stokes radius is 0.155nm.
  • the polyamide desalination layer of the reverse osmosis membrane mainly has network pores with a pore size of 0.1-0.3nm and aggregated pores with a pore size of 0.4-0.6nm. Pore structure.
  • boric acid The size of the boric acid molecule is close to the pore size of the network pore but smaller than the pore size of the aggregated pore. Therefore, in the process of reverse osmosis seawater desalination, boric acid will pass through the aggregated pore in the polyamide desalination layer, and even enter part of the network pore, resulting in the effect of reverse osmosis membrane on boron.
  • the removal rate is less than 90% (about 60% to 80%), so that a single reverse osmosis process cannot remove boron to the World Health Organization (WHO) recommended value of boron content in drinking water ( ⁇ 0.5mg/L ) level, the concentration of boron can only be further reduced by adding various pre-treatment and post-treatment processes or multi-stage reverse osmosis processes, which greatly increases energy consumption and cost. Therefore, it is necessary to improve the material and preparation process of the reverse osmosis membrane, and then realize the optimization of the performance by regulating the structure of the functional layer, and develop a seawater desalination reverse osmosis membrane product with a high boron removal rate, so that the reverse osmosis membrane can maintain the flux. And the high desalination rate at the same time greatly improves the boron removal rate.
  • WHO World Health Organization
  • Citation 1 discloses a blended hybrid deboronation affinity membrane and a preparation method thereof, including the following steps: (1) grinding ZXC700 special resin for boron removal into powder and sieving; (2) removing boron from substance A and ZXC700 Special resin powder, polyvinylpyrrolidone and organic solvent are mixed evenly, stirred, and left to stand at room temperature for vacuum degassing until no foaming, and the phase inversion precipitation method is used to prepare a blended hybrid deboronation affinity membrane; the A substance is polysulfone, Bisphenol A polysulfone, polyethersulfone or polyvinylidene fluoride.
  • the blended hybrid deboronation affinity membrane has high deboronation capacity, and the deboronation rate increases with the increase of the content of the special resin powder ZXC700 used for deboronation.
  • the deboronation affinity membrane belongs to the category of ultrafiltration membranes, only It has a high removal rate of boron, but has no removal effect on inorganic salts such as sodium chloride, and has a single effect.
  • Citation 2 discloses a fast and efficient deboronation hollow fiber composite membrane and its preparation method.
  • the hollow fiber composite membrane includes a polymer porous membrane, and the surface of the polymer porous membrane is a hyperbranched polyhydroxy structure polymer molecular brush; calculated in parts by mass, the polyhydroxy structure polymer molecular brush is composed of 1-4 parts of dopamine hydrochloride, 1-4 parts of polyethyleneimine, 2-8 parts of glycidol and 100 parts of Tris buffer solution with a concentration of 10 mM are used as preparation raw materials.
  • the hollow fiber composite membrane prepared by this method has a high deboronation rate, but the regularity of the hollow fiber membrane cannot be ensured during the membrane production process, which easily leads to the entanglement of the hollow fiber membranes and the broken wires, and it is difficult to prepare the membrane module. Industrial production cannot be achieved.
  • the present disclosure first provides a deboronation reverse osmosis membrane.
  • the deboronation reverse osmosis membrane of the present disclosure has high flux and high salt rejection while having higher boron removal.
  • the present disclosure also provides a method for preparing a deboronized reverse osmosis membrane, which is simple and easy to prepare, easy to obtain raw materials, and capable of mass production.
  • the present disclosure first provides a deboronation reverse osmosis membrane, which includes:
  • the support layer is formed on one surface of the substrate, the support layer contains a polymer and a pore-forming agent, and the support layer has a porous structure;
  • a desalination layer comprising polyamide
  • a nano-transition layer is located between the support layer and the desalination layer, and is in contact with the support layer and the desalination layer; wherein, the nano-transition layer contains cellulose nanocrystals.
  • the deboronated reverse osmosis membrane according to the present disclosure wherein the nano transition layer is formed on the surface of the support layer through covalent bonds;
  • the desalination layer is superimposed on the side of the nano transition layer opposite to the support layer through a covalent bond.
  • the deboronation reverse osmosis membrane according to the present disclosure wherein the polymer comprises polyacrylonitrile, or polyacrylonitrile and one or two selected from polysulfone, polyethersulfone, polyvinyl chloride, and polyetheretherketone a combination of the above; and/or
  • the pore-forming agent includes a macromolecule pore-forming agent or a small-molecule pore-forming agent; preferably, the macromolecular pore-forming agent includes one or more of polyethylene glycol, polyvinylpyrrolidone or polyvinyl alcohol. Combination; the small molecule pore-forming agent includes one or a combination of two or more of lithium chloride, calcium chloride or water.
  • the deboronation reverse osmosis membrane according to the present disclosure wherein the support layer is a support layer obtained by hydrolyzing the surface of the support layer by using a modifier;
  • the nano-transition layer is a nano-transition layer obtained by functionalizing its surface.
  • the diameter of the cellulose nanocrystals is 5-15 nm, preferably 5-10 nm; the length of the cellulose nanocrystals is 50-300 nm, preferably 50-100 nm.
  • the present disclosure also provides a method for preparing a deboronated reverse osmosis membrane according to the present disclosure, which includes the steps of composite molding the support layer, the nano-transition layer and the demineralization layer.
  • a desalination layer is formed on the surface of the nano transition layer opposite to the support layer to obtain a deboronated reverse osmosis membrane.
  • the preparation method further comprises the step of hydrolyzing the surface of the support layer with a modifier, preferably, the modifier includes an alkali agent.
  • the functionalization solution includes a first functionalization solution and the second functionalization solution;
  • the first functionalization solution includes a crosslinking agent; the second functionalization solution includes an amine monomer.
  • the preparation method according to the present disclosure wherein the desalination layer is formed using an oil phase monomer solution and the amine monomer.
  • the deboronation reverse osmosis membrane of the present disclosure has high flux and high salt rejection while having higher boron removal.
  • the cellulose nanocrystal transition layer of the present disclosure improves the stability and mechanical properties of the reverse osmosis membrane desalination layer.
  • the preparation method of the deboronizing reverse osmosis membrane of the present disclosure is simple and feasible, the raw materials are easy to obtain, and mass production can be realized.
  • numerical range represented by "numerical value A to numerical value B" means a range including the numerical values A and B at the endpoints.
  • substantially means that the error is less than 5%, or less than 3% or less than 1% compared with the relevant perfect standard or theoretical standard.
  • references to “some specific/preferred embodiments”, “other specific/preferred embodiments”, “embodiments”, etc. refer to the specific elements described in relation to the embodiment (eg, features, structures, properties, and/or characteristics) are included in at least one embodiment described herein, and may or may not be present in other embodiments. Additionally, it should be understood that the described elements may be combined in any suitable manner in the various embodiments.
  • a first aspect of the present disclosure provides a deboronated reverse osmosis membrane comprising:
  • the support layer is formed on one surface of the substrate, the support layer contains a polymer and a pore-forming agent, and the support layer has a porous structure;
  • the desalting layer being a polyamide desalting layer
  • a nano-transition layer is located between the support layer and the desalination layer, and is in contact with the support layer and the desalination layer; wherein, the nano-transition layer contains cellulose nanocrystals.
  • the nano-transition layer is formed on the surface of the support layer through covalent bonds; the desalination layer is superimposed on the nano-transition layer and the support layer through covalent bonds. the opposite side.
  • the deboronizing reverse osmosis membranes of the present disclosure include:
  • the support layer is formed on one surface of the substrate, the support layer contains a polymer and a pore-forming agent, and the support layer has a porous structure;
  • the nano-transition layer is formed on the surface of the support layer through covalent bonds, and the nano-transition layer contains cellulose nanocrystals;
  • a desalting layer is superimposed on the side of the nano transition layer opposite to the supporting layer through a covalent bond, and the desalting layer is a polyamide desalting layer.
  • the present disclosure introduces a nano-transition layer between the support layer and the desalination layer through covalent bonds, thereby improving the stability and mechanical properties of the existing reverse osmosis membrane.
  • the highly functionalized cellulose nanocrystals and their derivatives have strong boron trapping ability, which further improves the deboronation performance of the stacked loaded interfacial polymerized reverse osmosis membrane.
  • the supporting layer of the present disclosure is formed on one surface of the substrate, the supporting layer contains a polymer and a pore-forming agent, and the supporting layer has a porous structure.
  • the present disclosure can further form a nano-transition layer and a desalination layer by using a polymer to make the support layer have active groups.
  • the polymer includes polyacrylonitrile, or a combination of polyacrylonitrile and one or more selected from polysulfone, polyethersulfone, polyvinyl chloride, and polyetheretherketone.
  • the pore-forming agent includes a macromolecule pore-forming agent or a small-molecule pore-forming agent.
  • the support layer of the present disclosure can have a suitable pore structure, thereby improving the flux of the deboronized reverse osmosis membrane.
  • the present disclosure does not specifically limit the macromolecule pore-forming agent or the small-molecule pore-forming agent, and may be some macromolecular pore-forming agent or small-molecule pore-forming agent commonly used in the art. Including one or a combination of two or more of polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA) and the like.
  • the small molecule pore-forming agent includes one or a combination of two or more of lithium chloride, calcium chloride or water.
  • a polymeric pore former such as polyvinylpyrrolidone (PVP).
  • the support layer in order to make the surface of the support layer have a large number of active groups, is obtained by hydrolyzing the surface of the support layer by using a modifier. That is, the support layer is a support layer obtained by hydrolyzing the surface of the support layer using a modifier.
  • the modifier is not particularly limited in the present disclosure, and may be some modifiers commonly used in the art, preferably an alkaline agent is used as the modifier.
  • the alkali agent can be one or both of sodium hydroxide, potassium hydroxide, etc., preferably sodium hydroxide.
  • the nano transition layer of the present disclosure is located between the support layer and the desalination layer, and is in contact with the support layer and the desalination layer; wherein, the nano transition layer contains cellulose nanocrystals.
  • the cellulose nanocrystals are connected with the support layer and the desalination layer through covalent bonds, and the stability and mechanical properties of the deboronized reverse osmosis membrane are improved .
  • the nano transition layer of the present disclosure is formed on the surface of the support layer through covalent bonds; for example, it can be formed on the surface of the support layer by dipping or coating or spraying the support layer. the nano transition layer.
  • the nano transition layer is a nano transition layer obtained by functionalizing its surface.
  • the surface of the nano-transition layer obtained by surface functionalization treatment has multiple functional groups, such as amino groups, etc., which can provide a high density of reaction sites for interfacial polymerization, and eliminate the defects of the base film and the influence of the hydrolysis of oil-phase acid chlorides , promotes the formation of a highly cross-linked, ultra-thin polyamide desalination layer without aggregation pores, so that the deboronation reverse osmosis membrane of the present disclosure has high flux and high desalination rate and also has a higher boron removal rate.
  • the cellulose nanocrystals of the present disclosure are rod-shaped.
  • the diameter of the cellulose nanocrystals is 5nm-15nm, preferably 5nm-10nm; the length of the cellulose nanocrystals is 50nm-300nm, preferably It is 50nm ⁇ 100nm.
  • the desalination layer of the present disclosure is a polyamide desalination layer.
  • the polyamide desalination layer of the present disclosure is a highly cross-linked, ultra-thin polyamide desalination layer without aggregation pores, so that the deboronation reverse osmosis membrane has the characteristics of high flux and high desalination rate.
  • the desalted layer is derived from oil phase monomers and amine monomers.
  • the oil phase monomer includes one or a combination of two or more of terephthaloyl chloride, isophthaloyl chloride, phthaloyl chloride, cyclohexanetricarbonyl chloride, trimesoyl chloride, and glutaryl chloride .
  • the amine monomer may be one or a combination of two or more of m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, and the like.
  • a second aspect of the present disclosure provides a method for preparing a deboronated reverse osmosis membrane according to the present disclosure, which includes the steps of compositely molding a support layer, a nano-transition layer and a demineralization layer.
  • the preparation method of the deboronation reverse osmosis membrane disclosed in the present disclosure is simple and feasible, the raw materials are easy to obtain, and is suitable for mass production.
  • the preparation method of the present disclosure comprises the following steps:
  • a desalination layer is formed on the surface of the nano transition layer opposite to the support layer to obtain a deboronated reverse osmosis membrane.
  • the support layer is obtained by dissolving a polymer and a pore-forming agent in a first solvent to obtain a support layer solution, and then allowing the support layer solution to form a film on one surface of a substrate.
  • the polymer and pore former may be the polymer and pore former described in the first aspect; for the first solvent of the present disclosure, it may include N,N-dimethylformamide (DMF) , N,N-dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), one or a combination of two or more.
  • DMF N,N-dimethylformamide
  • DMAC N,N-dimethylacetamide
  • NMP N-methylpyrrolidone
  • DMSO dimethyl sulfoxide
  • the content of the polymer is 15wt%-20wt%, It is preferably 16wt% to 19wt%; the content of the pore former is 0.1wt% to 5wt%, preferably 0.4wt% to 4wt%; the content of the first solvent is 75wt% to 84.9wt%, preferably 77wt% % ⁇ 83.6wt%.
  • the content of the polymer is 15.5wt%, 16.5wt%, 17wt%, 17.5wt%, 18wt%, 18.5wt%, etc.; the content of the pore former is 0.5wt%, 1wt%, 1.5wt% %, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, etc.; the content of the first solvent is 74wt%, 76wt%, 78wt%, 80wt%, 82wt%, 83wt%, 84% etc.
  • the temperature may be appropriately increased for treatment.
  • the temperature may be 40°C to 100°C, preferably 50°C to 90°C, for example: 45°C, 55°C, 65°C, 75°C, 85°C, 95°C, and the like.
  • the support layer solution can be prepared by the following method: adding the pore-forming agent in proportion to the first solvent in a stirring state for mixing and dispersing, maintaining the stirring state and raising the temperature to 40-100° C., adding a polymer to it, and supplementing the remaining part
  • the first solvent is adjusted to 100 wt % to obtain a support layer solution.
  • the present disclosure obtains a polymer primary film by forming the support layer solution into a film.
  • the film formation can be formed by subjecting the prepared support layer solution to a solid-liquid phase conversion method. Specifically, the pre-prepared support layer solution is uniformly coated (such as blade coating) on the substrate, the substrate covered with the support layer solution is slowly immersed in the coagulation bath, and the polymer is obtained by scraping through the gel curing process.
  • the base material can be a non-woven fabric. Considering the alkali resistance of the non-woven fabric, polypropylene non-woven fabric is preferably used.
  • the main component of the coagulation bath of the present disclosure is water.
  • the temperature of the coagulation bath needs to be controlled at 10°C to 25°C, for example: 12°C, 15°C, 18°C, 20°C, 22°C etc.; the treatment time in the solidification solution is 200s to 400s, for example: 220s, 250s, 280s, 300s, 320s, 350s, 380s, etc.
  • the step of defoaming treatment is also included, in order to make the surface structure and internal structure of the polymer primary film more suitable for the preparation of the nano-transition layer and the desalination layer, before forming the support layer solution into a film, the step of defoaming treatment is also included, in the present disclosure, all defoaming processes are carried out in a vacuum defoaming box, and the vacuum pump pressure is -100kPa ⁇ -60MPa, for example: -90kPa, -80kPa, -70kPa, etc.
  • the preparation method further includes the step of hydrolyzing the surface of the support layer with a modifier, preferably, the modifier includes an alkaline agent.
  • the alkali agent can be one or a combination of two of sodium hydroxide, potassium hydroxide and the like.
  • the modifier is an alkaline aqueous solution, and in the alkaline aqueous solution, the concentration of the alkaline agent is 3wt%-8wt%, for example: 4wt%, 5wt%, 6wt%, 7wt%, etc.
  • the modification treatment is preferably carried out at a certain temperature, and the temperature of the modification treatment is 40°C to 80°C, for example: 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, 75°C, etc.;
  • the modification time is 5min-30min, for example: 10min, 15min, 20min, 25min, etc.
  • the modifying step comprises subjecting the nascent polymer membrane to an aqueous alkaline solution for surface hydrolysis modification.
  • the present disclosure can also perform post-treatment on the obtained modified polymer nascent film, the post-treatment includes washing it to neutrality with deionized water, thereby obtaining a support layer.
  • the nanotransition layer solution is obtained by dissolving the cellulose nanocrystals in the first solvent.
  • the first solvent which is not particularly limited in the present disclosure, may be the first solvent used in the support layer. Specifically, it may include N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAC), N-methylpyrrolidone (NMP), dimethylsulfoxide (DMSO) among one or a combination of both.
  • the mass ratio of cellulose nanocrystals to the first solvent can be 1:80-120, for example: 1:85, 1:90, 1:95, 1:100, 1:105, 1:110, 1:115, etc.
  • a catalyst can be added to make the cellulose nanocrystals in the nano-transition layer and the active groups on the surface of the support layer better. A chemical reaction occurs to create a covalent bond.
  • the catalyst is N,N-dicyclohexylcarbodiimide (DCC), N,N-diisopropylcarbodiimide, 1-cyclohexyl-2-morpholinohexylcarbodiimide One or a combination of two or more of tosylate, 4-dimethylaminopyridine (DMAP), 2-aminopyridine, 2-hydroxyethylpyridine, and 3,4-and aminopyridine.
  • the catalysts used are N,N-dicyclohexylcarbodiimide (DCC) and 4-dimethylaminopyridine (DMAP).
  • the addition amount of the catalyst is not particularly limited in the present disclosure, and may be the addition amount commonly used in the art.
  • the cellulose nanocrystals and the catalyst can be added to the first solvent for ultrasonic dispersion, and the ultrasonic dispersion time can be 5 min to 20 min, so as to obtain a uniformly mixed CNC-DMF solution.
  • the temperature can be 25°C to 80°C, for example: 30°C, 35°C, 40°C, 45°C, 50°C, 55°C °C, 60 °C, 65 °C, 70 °C, etc.
  • nano transition layer solution is formed on the surface of the support layer to form a nano transition layer film to obtain an intermediate product.
  • the support layer can be immersed in the nano-transition layer solution, so that the nano-transition layer film is formed on the surface of the support layer.
  • the residual solution on its surface can be removed, for example, by drying or wiping to remove the residual solution on the surface.
  • it is immersed in the transition layer solution for 10 to 30 minutes, such as 15 minutes, 20 minutes, 25 minutes, etc.; and then the residual solution is removed to obtain an intermediate product.
  • the position of the intermediate product with the nano-transition layer film is functionalized to obtain a nano-transition layer.
  • the functionalization treatment is performed using a functionalization solution, the functionalization solution includes a first functionalization solution and a second functionalization solution; wherein the first functionalization solution contains a cross-linking agent; the second functionalization solution
  • the functionalization solution contains amine monomers.
  • the intermediate product can be immersed in the first functionalization solution for 10min-60min, for example: 20min, 30min, 40min, 50min, etc., then taken out to remove the residual solution on the surface, and then immersed in the second functionalization solution for 10min-60min, for example: 20min, 30min, 40min, 50min, etc., then take out and rinse with deionized water to obtain a nano transition layer.
  • the first functionalization solution for 10min-60min for example: 20min, 30min, 40min, 50min, etc.
  • the second functionalization solution for 10min-60min for example: 20min, 30min, 40min, 50min, etc.
  • the functionalized nano-transition layer provides a high density of reaction sites for interfacial polymerization, eliminates the influence of base film defects and oil-phase acid chloride hydrolysis, and promotes the formation of a highly cross-linked, ultra-thin polyamide desalination layer without aggregation pores.
  • the prepared reverse osmosis membrane has high flux, high salt rejection and higher boron rejection.
  • the high functionalization endows the cellulose nanocrystals and their derivatives with strong boron capture ability, which hinders the permeation of boron and further improves the deboronation performance of the laminated loaded interface polymer composite reverse osmosis membrane. It has the characteristics of solving the low deboronation performance of the reverse osmosis membrane in the prior art.
  • the crosslinking agent can be dissolved in the second solvent to obtain the first functionalized solution.
  • the crosslinking agent may be one or a combination of two or more of methyl acrylate (MA), methacrylate, methyl methacrylate, butyl acrylate, ethyl methacrylate, and the like.
  • the second solvent may be one or a combination of two or more of tetrahydrofuran (THF), acetone, toluene, anisole, dichloromethane, and the like.
  • the mass ratio of the crosslinking agent to the second solvent may be 1:1-10, preferably 1:2-8, for example: 1:3, 1:4, 1:5, 1:6, 1:7, 1:9, etc.
  • a catalyst can be added when preparing the first functionalized solution, so that the cellulose nanocrystals and the amine monomer in the nano-transition layer can be better formed. chemical reaction to create a covalent bond.
  • the catalyst may be ⁇ -bromoisobutyryl bromide (BIB), 2,2-dibromomethyl-1,3-dibromopropane, dibromomethylbenzene, ⁇ , ⁇ -dibromide benzyl , ⁇ , ⁇ -dibromoacetate, ⁇ , ⁇ -dibromo-p-xylene, etc., one or more combinations.
  • the addition amount of the catalyst is not specifically limited in the present disclosure, and may be the addition amount commonly used in the art.
  • the method for preparing the first functionalized solution may be to sequentially add the crosslinking agent and the catalyst to the second solvent and mix uniformly to obtain the first functionalized solution for later use.
  • the temperature can be 50-80°C, for example: 55°C, 60°C, 65°C, 70°C, 75°C, etc.
  • the amine monomer can be dissolved in the second solvent to obtain the second functionalization solution.
  • the amine monomer can be one or a combination of two or more of m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, etc.
  • the second solvent can be tetrahydrofuran (THF), acetone, One or a combination of two or more of toluene, anisole, and dichloromethane.
  • the mass ratio of the amine monomer to the second solvent may be 1:5-20, preferably 1:7-15, for example: 1:6, 1:8, 1:9, 1:10, 1:11, 1:12, 1:14, 1:16, 1:18, 1:19, etc.
  • a catalyst can be added to make the cellulose nanocrystals in the transition layer and the amine monomer chemically react better. , to create a covalent bond.
  • the catalyst can be tetra-n-butylammonium bromide (TBAB), triethylbenzylamine chloride, dodecyltrimethylammonium bromide, hexadecyltrimethylammonium bromide, One or a combination of two or more of dodecyl trimethyl ammonium chloride, etc.
  • TBAB tetra-n-butylammonium bromide
  • the addition amount of the catalyst is not specifically limited in the present disclosure, and may be the addition amount commonly used in the art.
  • the preparation method of the second functionalized solution may be to sequentially add the amine monomer and the catalyst into the second solvent and mix evenly to obtain the second functionalized solution for later use.
  • the temperature can be 50-80°C, for example: 55°C, 60°C, 65°C, 70°C, 75°C, etc.
  • the desalination layer of the present disclosure may be formed directly on the surface of the nano transition layer.
  • the desalting layer can be formed using the oil phase monomer solution and the amine monomer in the second functionalization solution.
  • the obtained support layer formed with the nano transition layer can be immersed in the oil phase monomer solution and the humectant solution to obtain a deboronated reverse osmosis membrane.
  • the order of immersion in the oil phase monomer solution and the humectant solution is not particularly limited in the present disclosure, and the immersion in the humectant solution or the oil phase monomer solution may be immersed first. Preferably, it can be immersed in the oil phase monomer solution first, and then immersed in the humectant solution.
  • the membrane sheet may be immersed in the oil phase monomer solution first, and the immersion time should not be too long.
  • the time of immersion in the oil phase monomer solution can be 30s to 60s, for example: 35s, 40s, 45s, 50s, 55s, etc.; then use the acid solution to clean the oil phase immersion product and the residual solution, and the cleaning time is 3 min to 6 min; and finally immersed in the humectant solution, and the time of immersion in the humectant solution may be 3 min to 6 min, for example, 4 min, 5 min, and the like.
  • a deboronized reverse osmosis membrane After being taken out and dried, a deboronized reverse osmosis membrane can be obtained, and the drying temperature can be 50°C to 90°C, preferably 70°C to 80°C, for example: 55°C, 60°C, 65°C, 70°C, 75°C, 85°C Wait.
  • the oil phase active monomer can be dissolved in the third solvent to obtain the oil phase monomer solution.
  • the oil-phase active monomer is one or more of terephthaloyl chloride, isophthaloyl chloride, phthaloyl chloride, cyclohexanetriformyl chloride, trimesoyl chloride, and glutaryl chloride. combination.
  • the third solvent can be a common organic solvent, for example: one or a combination of two or more of n-hexane, cyclohexane, n-heptane, toluene, chloroform, isopar G, etc.
  • the concentration of the oil phase active monomer is 0.05wt% to 3.0wt%
  • the third The added amount of the solvent is 97wt%-99.95wt%.
  • the oil phase monomer can be added in an amount of 0.5wt%, 1wt%, 1.5wt%, 2wt%, 2.5wt%, 2.8wt%, etc.; the third solvent can be added in an amount of 97.2wt% , 97.5wt%, 98wt%, 98.5wt%, 99wt%, 99.5wt%, etc.
  • the acid solution used in the cleaning process may be hydrochloric acid dissolved in water, wherein, based on the total mass of the acid solution, the concentration of the acid may be 0.5wt% to 3.0wt%.
  • the acidic substance is hydrogen chloride.
  • the humectant solution may be obtained by dissolving the humectant in the fourth solvent.
  • the moisturizing agent is one or a combination of two or more selected from glycerol, phenethyl alcohol, glycerol monoacetate, isopropanol, and mannitol.
  • the fourth solvent can be a common aqueous solvent, such as deionized water and the like.
  • the concentration of the humectant is 5wt%-15.0wt%, for example: 7wt%, 9wt%, 11wt%, 13wt% %, 14wt%, etc.; the addition amount of the fourth solvent is 85wt%-95wt%; for example: 86wt%, 87wt%, 89wt%, 91wt%, 93wt%, etc.
  • cellulose nanocrystal solution Mix cellulose nanocrystals (CNC) and N,N-dimethylformamide (DMF) in a mass ratio of 1:100, add catalyst N,N-dicyclohexylcarbon Diimine (DCC) and 4-dimethylaminopyridine (DMAP) were ultrasonically dispersed for 10 minutes to obtain a well-mixed CNC-DMF solution, which was heated to 70°C for later use;
  • CNC-DMF N,N-dimethylformamide
  • DCC catalyst N,N-dicyclohexylcarbon Diimine
  • DMAP 4-dimethylaminopyridine
  • support layer 0.1wt% polyvinylpyrrolidone was added to N,N-dimethylformamide (DMF) in a stirring state for mixing and dispersion, maintaining the stirring state and raising the temperature to 70°C, adding 15.0wt% to it. % polyacrylonitrile, and the remainder was supplemented by N,N-dimethylformamide (DMF) to 100 wt% to obtain a polymer homogeneous solution.
  • DMF N,N-dimethylformamide
  • Example 1 the diameter of the cellulose nanocrystals is 5 nm and the length is 50 nm; the material of the non-woven substrate is polypropylene (PP).
  • PP polypropylene
  • cellulose nanocrystal solution Mix cellulose nanocrystals (CNC) and N,N-dimethylformamide (DMF) in a mass ratio of 1:100, add catalyst N,N-dicyclohexylcarbon Diimine (DCC) and 4-dimethylaminopyridine (DMAP) were ultrasonically dispersed for 10 minutes to obtain a well-mixed CNC-DMF solution, which was heated to 70°C for later use;
  • CNC-DMF N,N-dimethylformamide
  • DCC catalyst N,N-dicyclohexylcarbon Diimine
  • DMAP 4-dimethylaminopyridine
  • Example 2 the diameter of the cellulose nanocrystals is 10 nm and the length is 50 nm; the material of the non-woven fabric substrate is polypropylene (PP).
  • PP polypropylene
  • cellulose nanocrystal solution Mix cellulose nanocrystals (CNC) and N,N-dimethylformamide (DMF) in a mass ratio of 1:100, add catalyst N,N-dicyclohexylcarbon Diimine (DCC) and 4-dimethylaminopyridine (DMAP) were ultrasonically dispersed for 10 minutes to obtain a well-mixed CNC-DMF solution, which was heated to 70°C for later use;
  • CNC-DMF N,N-dimethylformamide
  • DCC catalyst N,N-dicyclohexylcarbon Diimine
  • DMAP 4-dimethylaminopyridine
  • Example 3 the diameter of the cellulose nanocrystals is 10 nm and the length is 100 nm; the material of the non-woven substrate is polypropylene (PP).
  • PP polypropylene
  • cellulose nanocrystal solution Mix cellulose nanocrystals (CNC) and N,N-dimethylformamide (DMF) in a mass ratio of 1:100, add catalyst N,N-dicyclohexylcarbon Diimine (DCC) and 4-dimethylaminopyridine (DMAP) were ultrasonically dispersed for 10 minutes to obtain a well-mixed CNC-DMF solution, which was heated to 70°C for later use;
  • CNC-DMF N,N-dimethylformamide
  • DCC catalyst N,N-dicyclohexylcarbon Diimine
  • DMAP 4-dimethylaminopyridine
  • Example 4 the diameter of the cellulose nanocrystals is 10 nm and the length is 200 nm; the material of the non-woven substrate is polypropylene (PP).
  • PP polypropylene
  • cellulose nanocrystal solution Mix cellulose nanocrystals (CNC) and N,N-dimethylformamide (DMF) in a mass ratio of 1:100, add catalyst N,N-dicyclohexylcarbon Diimine (DCC) and 4-dimethylaminopyridine (DMAP) were ultrasonically dispersed for 10 minutes to obtain a well-mixed CNC-DMF solution, which was heated to 70°C for later use;
  • CNC-DMF N,N-dimethylformamide
  • DCC catalyst N,N-dicyclohexylcarbon Diimine
  • DMAP 4-dimethylaminopyridine
  • Example 5 the diameter of the cellulose nanocrystals was 15 nm and the length was 300 nm; the material of the non-woven substrate was polypropylene (PP).
  • PP polypropylene
  • Preparation of support layer 5.0wt% polyvinylpyrrolidone was added to N,N-dimethylformamide (DMF) in a stirring state for mixing and dispersion, maintaining the stirring state and raising the temperature to 70°C, adding 18.0wt% to it. % polyacrylonitrile, and the remainder was supplemented by N,N-dimethylformamide (DMF) to 100 wt% to obtain a polymer homogeneous solution. After vacuum defoaming treatment at -80kPa, filtered, cooled to room temperature, uniformly coated on the non-woven substrate by a scraper system, and then immersed in a deionized water coagulation bath at 15°C for 300s to obtain porous support layer.
  • DMF N,N-dimethylformamide
  • the material of the non-woven substrate is polypropylene (PP).
  • the deboronation reverse osmosis membranes of Examples 1 to 5 were very excellent in all of the water flux, the salt rejection rate, and the boron removal rate. Therefore, compared with the reverse osmosis membrane of Comparative Example 1, the deboronation reverse osmosis membranes of Examples 1 to 5 of the present application have comparable flux and high salt rejection. At the same time, it has a higher deboronation rate.

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Abstract

一种脱硼反渗透膜及其制备方法。脱硼反渗透膜包括：支撑层，支撑层形成于基材的一个表面，支撑层包含有聚合物和成孔剂，且支撑层具有多孔结构；脱盐层，脱盐层包含有聚酰胺；以及纳米过渡层，纳米过渡层位于支撑层和脱盐层之间，且与支撑层和脱盐层相接触；其中，纳米过渡层包含有纤维素纳米晶体。

Description

脱硼反渗透膜及其制备方法 技术领域
本公开涉及一种脱硼反渗透膜及其制备方法，具体涉及一种层叠装载界面聚合高脱硼海水淡化膜及其制备方法，属于水处理领域。
背景技术
随着世界人口的增长与工业的迅速发展，水资源短缺已经成为制约社会经济发展的瓶颈。海水淡化是当前解决淡水资源危机的有效途径之一，而反渗透膜法用于海水淡化已成为主要技术之一，估计占世界海水淡化总量的44％，并逐年持续增长。芳香族聚酰胺复合膜是当前应用最普遍的反渗透膜，具有良好的水通量和脱盐率，以及更宽的操作温度和pH范围。然而限制芳香族聚酰胺反渗透膜应用的一个主要因素是其对不带电小分子相对低的脱除率，如硼酸。
硼是海水中的一种微量元素，在海水中主要以不带电硼酸分子的形式存在，平均浓度为4～7mg/L，最高也可达9.6mg/L。硼的含量超过一定限度是有毒有害的，根据世界卫生组织(WHO)的报告，水中的硼含量超过2.4mg/L时会使植物中毒，过量的硼也会使人出现头晕、恶心及肾衰竭等症状。WHO建议饮用水中的硼含量应低于0.5mg/L。因此，硼的去除是海水淡化过程中的重要指标。
海水中的硼酸大部分(约95％)以分子的形式存在，因此反渗透膜去除盐离子的静电排斥机制变得无效，不能像脱盐一样有效去除不带电的硼酸，而主要以孔径筛分和空间位阻机制除硼。不带电硼酸分子的尺寸为0.275nm，斯托克斯半径为0.155nm，反渗透膜的聚酰胺脱盐层主要存在孔径为0.1～0.3nm的网络孔和孔径为0.4～0.6nm的聚集孔两种孔型结构。
硼酸分子的尺寸接近网络孔孔径而小于聚集孔孔径，因此在反渗透海水淡化过程中，硼酸会透过聚酰胺脱盐层中的聚集孔，甚至进入部分网络孔内， 导致反渗透膜对硼的脱除率低于90％(约为60％～80％)，从而使单一的反渗透工艺无法将硼去除至世界卫生组织(WHO)对饮用水含硼量的建议值(＜0.5mg/L)水平，只能通过添加各种前处理和后处理工艺或多级反渗透工艺来实现进一步降低硼的浓度，大大增加了能耗和成本。因此，需对反渗透膜的材料及制备工艺进行改进，进而通过对功能层结构的调控来实现性能的优化，开发具有高脱硼率的海水淡化反渗透膜产品，使得反渗透膜维持通量和高脱盐率的同时大大提高脱硼率。
引用文献1公开了一种共混杂化脱硼亲和膜及其制备方法，包括如下步骤：(1)将ZXC700除硼专用树脂研磨成粉，过筛；(2)将A物质、ZXC700除硼专用树脂粉、聚乙烯吡咯烷酮和有机溶剂混匀，搅拌，室温下静置真空脱泡至无泡为止，用相转化沉淀法制成共混杂化脱硼亲和膜；所述A物质为聚砜、双酚A聚砜、聚醚砜或聚偏氟乙烯。该共混杂化脱硼亲和膜具有很高的脱硼能力，脱硼率随所用脱硼专用树脂粉ZXC700含量的增加而升高，但所述脱硼亲和膜属于超滤膜范畴，仅对硼有较高的脱除率，对氯化钠等无机盐无脱除功效，效果单一，无法达到海水淡化反渗透膜对海水的脱盐功效，不能直接用于海水淡化。
引用文献2公开了一种快速、高效脱硼中空纤维复合膜及其制备方法。所述中空纤维复合膜包括聚合物多孔膜，聚合物多孔膜的表面为超支化多羟基结构聚合物分子刷；按质量份数计算，多羟基结构聚合物分子刷以1-4份盐酸多巴胺、1-4份聚乙烯亚胺、2-8份环氧丙醇及100份浓度为10mM的Tris缓冲溶液为制备原料。该方法所制备的一种中空纤维复合膜具有较高的脱硼率，但制膜过程中无法确保中空纤维膜的规整性，易导致中空纤维膜相互缠绕而断丝，且难以制备膜组件，无法实现工业化生产。
引用文献
引用文献1：CN103752188A
引用文献2：CN106422809A
发明内容
发明要解决的问题
鉴于现有技术中存在的技术问题，例如：海水淡化反渗透膜脱硼性能低的问题等，本公开首先提供一种脱硼反渗透膜。本公开的脱硼反渗透膜具有高通量和高脱盐率的同时具有更高的脱硼率。
进一步地，本公开还提供了一种脱硼反渗透膜的制备方法，其制备方法简单易行，原料易于获取，能够实现大批量生产。
用于解决问题的方案
本公开首先提供了一种脱硼反渗透膜，其包括：
支撑层，所述支撑层形成于基材的一个表面，所述支撑层包含有聚合物和成孔剂，且所述支撑层具有多孔结构；
脱盐层，所述脱盐层包含有聚酰胺；以及
纳米过渡层，所述纳米过渡层位于支撑层和脱盐层之间，且与所述支撑层和脱盐层相接触；其中，所述纳米过渡层包含有纤维素纳米晶体。
根据本公开的脱硼反渗透膜，其中，所述纳米过渡层通过共价键形成于所述支撑层的表面；
所述脱盐层通过共价键叠加在所述纳米过渡层的与所述支撑层相对的一面。
根据本公开的脱硼反渗透膜，其中，所述聚合物包括聚丙烯腈，或聚丙烯腈与选自聚砜、聚醚砜、聚氯乙烯、聚醚醚酮中的一种或两种以上的组合；和/或
所述成孔剂包括高分子成孔剂或小分子成孔剂；优选地，所述高分子成孔剂包括聚乙二醇、聚乙烯吡咯烷酮或聚乙烯醇中的一种或两种以上的组合；所述小分子成孔剂包括氯化锂、氯化钙或水的一种或两种以上的组合。
根据本公开的脱硼反渗透膜，其中，所述支撑层为通过使用改性剂对其表面进行水解改性得到的支撑层；
所述纳米过渡层为对其表面进行功能化处理得到的纳米过渡层。
根据本公开的脱硼反渗透膜，其中，所述纤维素纳米晶体的直径为5～15nm，优选5～10nm；所述纤维素纳米晶体的长度为50～300nm，优选为50～100nm。
本公开还提供了一种根据本公开所述的脱硼反渗透膜的制备方法，其包括将支撑层、纳米过渡层以及脱盐层复合成型的步骤。
根据本公开的制备方法，其中，包括以下步骤：
将聚合物和成孔剂溶于第一溶剂中，得到支撑层溶液，然后使所述支撑层溶液在基材的一个表面成膜，得到支撑层；
将纤维素纳米晶体溶于第一溶剂中，得到纳米过渡层溶液，使所述纳米过渡层溶液在所述支撑层的表面形成纳米过渡层膜，得到中间产物；
对所述中间产物的具有所述纳米过渡层膜的位置进行功能化处理，得到纳米过渡层；
在所述纳米过渡层的与所述支撑层相对的表面形成脱盐层，得到脱硼反渗透膜。
根据本公开的制备方法，其中，所述制备方法还包括利用改性剂对所述支撑层的表面进行水解改性处理的步骤，优选地，所述改性剂包括碱剂。
根据本公开的制备方法，其中，使用功能化溶液进行所述功能化处理，所述功能化溶液包括第一功能化溶液和所述第二功能化溶液；其中，
所述第一功能化溶液包含交联剂；所述第二功能化溶液包含胺单体。
根据本公开的制备方法，其中，利用油相单体溶液和所述胺单体形成所述脱盐层。
发明的效果
本公开的脱硼反渗透膜具有高通量和高脱盐率的同时具有更高的脱硼率。
进一步地，本公开的纤维素纳米晶体过渡层提高了反渗透膜脱盐层的稳定性和机械性。
进一步地，本公开的脱硼反渗透膜的制备方法简单易行，原料易于获取， 能够实现大批量生产。
具体实施方式
以下，针对本公开的内容进行详细说明。以下所记载的技术特征的说明基于本公开的代表性的实施方案、具体例子而进行，但本公开不限定于这些实施方案、具体例子。需要说明的是：
本说明书中，使用“数值A～数值B”表示的数值范围是指包含端点数值A、B的范围。
本说明书中，如没有特殊声明，则“多”、“多种”、“多个”等中的“多”表示2或以上的数值。
本说明书中，所述“基本上”、“大体上”或“实质上”表示于相关的完美标准或理论标准相比，误差在5％以下，或3％以下或1％以下。
本说明书中，如没有特别说明，则“％”均表示质量百分含量。
本说明书中，使用“可以”表示的含义包括了进行某种处理以及不进行某种处理两方面的含义。
本说明书中，“任选的”或“任选地”是指接下来描述的事件或情况可发生或可不发生，并且该描述包括该事件发生的情况和该事件不发生的情况。
本说明书中，所提及的“一些具体/优选的实施方案”、“另一些具体/优选的实施方案”、“实施方案”等是指所描述的与该实施方案有关的特定要素(例如，特征、结构、性质和/或特性)包括在此处所述的至少一种实施方案中，并且可存在于其它实施方案中或者可不存在于其它实施方案中。另外，应理解，所述要素可以任何合适的方式组合在各种实施方案中。
<第一方面>
本公开的第一方面提供了一种脱硼反渗透膜，其包括：
支撑层，所述支撑层形成于基材的一个表面，所述支撑层包含有聚合物和成孔剂，且所述支撑层具有多孔结构；
脱盐层，所述脱盐层为聚酰胺脱盐层；以及
纳米过渡层，所述纳米过渡层位于支撑层和脱盐层之间，且与所述支撑层和脱盐层相接触；其中，所述纳米过渡层包含有纤维素纳米晶体。
进一步地，考虑到制备时的操作难易程度，所述纳米过渡层通过共价键形成于所述支撑层的表面；所述脱盐层通过共价键叠加在纳米过渡层的与所述支撑层相对的一面。
在一些具体的实施方案中，本公开的脱硼反渗透膜包括：
支撑层，所述支撑层形成于基材的一个表面，所述支撑层包含有聚合物和成孔剂，且所述支撑层具有多孔结构；
纳米过渡层，所述纳米过渡层通过共价键形成于所述支撑层的表面，且所述纳米过渡层包含有纤维素纳米晶体；
脱盐层，所述脱盐层通过共价键叠加在所述纳米过渡层的与所述支撑层相对的一面，且所述脱盐层为聚酰胺脱盐层。
本公开通过共价键在支撑层和脱盐层之间引入一层纳米过渡层，提高了现有的反渗透膜的稳定性和机械性。同时，高度功能化后纤维素纳米晶体及其衍生物具有很强的硼捕获能力，进一步提升了层叠装载界面聚合反渗透膜的脱硼性能。
支撑层
本公开的所述支撑层形成于基材的一个表面，所述支撑层包含有聚合物和成孔剂，且所述支撑层具有多孔结构。本公开通过使用聚合物使支撑层具有活性基团，从而可以进一步形成纳米过渡层和脱盐层。
在一些具体的实施方案中，所述聚合物包括聚丙烯腈，或聚丙烯腈与选自聚砜、聚醚砜、聚氯乙烯、聚醚醚酮中的一种或两种以上的组合。所述成孔剂包括高分子成孔剂或小分子成孔剂。本公开通过使用成孔剂，可以使本公开的支撑层具有合适的孔结构，从而提高脱硼反渗透膜的通量。
具体地，本公开对高分子成孔剂或小分子成孔剂不作特别限定，可以是本领域常用的一些高分子成孔剂或小分子成孔剂，具体地，所述高分子成孔剂包括聚乙二醇(PEG)、聚乙烯吡咯烷酮(PVP)、聚乙烯醇(PVA)等中 的一种或两种以上的组合。所述小分子成孔剂包括氯化锂、氯化钙或水等中的一种或两种以上的组合。但是考虑到本公开对孔结构的要求，优选使用高分子成孔剂，例如聚乙烯吡咯烷酮(PVP)。
在一些具体的实施方案中，为了使支撑层表面具有大量的活性基团，所述支撑层通过使用改性剂对其表面进行水解改性得到。即所述支撑层为通过使用改性剂对其表面进行水解改性得到的支撑层。
对于改性剂，本公开不作特别限定，可以是本领域常用的一些改性剂，优选使用碱剂作为改性剂。具体地，所述碱剂可以是氢氧化钠、氢氧化钾等中的一种或两种，优选为氢氧化钠。
纳米过渡层
本公开的纳米过渡层位于支撑层和脱盐层之间，且与所述支撑层和脱盐层相接触；其中，所述纳米过渡层包含有纤维素纳米晶体。
在本公开中，通过在支撑层和脱盐层之间引入纳米过渡层，使纤维素纳米晶体通过共价键与支撑层和脱盐层相连接，提高了脱硼反渗透膜的稳定性和机械性。
在一些具体的实施方案中，本公开的纳米过渡层通过共价键形成于所述支撑层的表面；例如可以通过对支撑层浸渍或涂敷或喷涂等方式，在所述支撑层的表面形成所述纳米过渡层。
在一些具体的实施方案中，所述纳米过渡层为对其表面进行功能化处理得到的纳米过渡层。经表面功能化处理得到的纳米过渡层的表面具有多个功能性基团，例如氨基等，从而使得能够为界面聚合提供高密度的反应位点，消除了基膜缺陷和油相酰氯水解的影响，促进形成无聚集孔的高交联度、超薄聚酰胺脱盐层，使得本公开的脱硼反渗透膜具有高通量和高脱盐率的同时具有更高的脱硼率。
作为优选，本公开的所述纤维素纳米晶体呈棒状，具体地，所述纤维素纳米晶体的直径为5nm～15nm，优选5nm～10nm；所述纤维素纳米晶体的长度为50nm～300nm，优选为50nm～100nm。
脱盐层
本公开的脱盐层为聚酰胺脱盐层。本公开的聚酰胺脱盐层是无聚集孔的高交联度、超薄的聚酰胺脱盐层，使脱硼反渗透膜具有高通量和高脱盐率的特点。
在一些具体的实施方案中，所述脱盐层源自于油相单体和胺单体。具体地，所述油相单体包括对苯二甲酰氯、间苯二甲酰氯、邻苯二甲酰氯、环己三甲酰氯、均苯三甲酰氯、戊二酰氯的一种或两种以上的组合。所述胺单体可以是间苯二胺、邻苯二胺、对苯二胺等中的一种或两种以上的组合。
<第二方面>
本公开的第二方面提供了一种根据本公开所述的脱硼反渗透膜的制备方法，其包括将支撑层、纳米过渡层以及脱盐层复合成型的步骤。本公开的脱硼反渗透膜的制备方法简单易行，原料易于获取，适合大批量生产。
在一些具体的实施方案中，本公开的制备方法包括以下步骤：
将聚合物和成孔剂溶于第一溶剂中，得到支撑层溶液，然后使所述支撑层溶液在基材的一个表面成膜，得到支撑层；
将纤维素纳米晶体溶于第一溶剂中，得到纳米过渡层溶液，使所述纳米过渡层溶液在所述支撑层的表面形成纳米过渡层膜，得到中间产物；
对所述中间产物的具有所述纳米过渡层膜的位置进行功能化处理，得到纳米过渡层；
在所述纳米过渡层的与所述支撑层相对的表面形成脱盐层，得到脱硼反渗透膜。
支撑层的制备
在本公开中，通过将聚合物和成孔剂溶于第一溶剂中，得到支撑层溶液，然后使所述支撑层溶液在基材的一个表面成膜，从而得到支撑层。
具体地，对于聚合物和成孔剂，其可以是第一方面所述的聚合物和成孔剂；对于本公开的第一溶剂，其可以包括N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAC)、N-甲基吡咯烷酮(NMP)、二甲基亚砜(DMSO) 中的一种或两种以上的组合。
在一些具体的实施方案中，为了更好的使支撑层溶液通过固-液相转化法成膜，以所述支撑层溶液的总质量计，所述聚合物的含量为15wt％～20wt％，优选为16wt％～19wt％；所述成孔剂的含量为0.1wt％～5wt％，优选为0.4wt％～4wt％；所述第一溶剂的含量为75wt％～84.9wt％，优选为77wt％～83.6wt％。具体地，所述聚合物的含量为15.5wt％、16.5wt％、17wt％、17.5wt％、18wt％、18.5wt％等；所述成孔剂的含量为0.5wt％、1wt％、1.5wt％、2wt％、2.5wt％、3wt％、3.5wt％、4wt％、4.5wt％等；所述第一溶剂的含量为74wt％、76wt％、78wt％、80wt％、82wt％、83wt％、84％等。优选地，在配制支撑层溶液时，为了加速溶质的溶解，可以适当提高温度进行处理。具体地，所述温度可以是40℃～100℃，优选为50℃～90℃，例如：45℃、55℃、65℃、75℃、85℃、95℃等。
具体地，可以通过以下方法制备得到支撑层溶液：将成孔剂按比例加入处于搅拌状态的第一溶剂中进行混合分散，维持搅拌状态升温至40～100℃，向其中加入聚合物，剩余部分补充第一溶剂至100wt％，得到支撑层溶液。
进一步地，本公开通过使所述支撑层溶液成膜，得到聚合物初生膜。为了得到性能优异的聚合物初生膜，所述成膜可以是将所制得的支撑层溶液经过固-液相转化法成膜。具体地，即将事先配制好的支撑层溶液均匀涂覆(如刮涂)在基材上，使覆有支撑层溶液的基材缓慢浸入凝固浴中，经过凝胶固化过程，刮制得到聚合物初生膜，作为优选，所述基材可以是无纺布，考虑到无纺布的耐碱性，优选使用聚丙烯无纺布。
作为优选，本公开的凝固浴主要成分为水，为保证两相间溶剂的扩散速率，凝固浴温度需控制为10℃～25℃，例如：12℃、15℃、18℃、20℃、22℃等；在凝固溶中的处理时间为200s～400s，例如：220s、250s、280s、300s、320s、350s、380s等。
在一些具体的实施方案中，为了使聚合物初生膜的表面结构及内部结构更加适合制备纳米过渡层及脱盐层，在使所述支撑层溶液成膜之前，还包括 脱泡处理的步骤，在本公开中，所有脱泡过程均在真空脱泡箱中进行，真空泵压力为-100kPa～-60MPa，例如：-90kPa、-80kPa、-70kPa等。
在一些具体的实施方案中，所述制备方法还包括利用改性剂对所述支撑层的表面进行水解改性处理的步骤，优选地，所述改性剂包括碱剂。具体地，所述碱剂可以是氢氧化钠、氢氧化钾等中的一种或两种的组合。
作为优选，所述改性剂为碱性水溶液，所述碱性水溶液中，碱剂的浓度为3wt％～8wt％，例如：4wt％、5wt％、6wt％、7wt％等。进行改性处理优选在一定的温度下进行，所述改性处理的温度为40℃～80℃，例如：45℃、50℃、55℃、60℃、65℃、70℃、75℃等；改性的时间为5min～30min，例如：10min、15min、20min、25min等。
在一些优选的实施方案中，所述改性步骤包括将聚合物初生膜置于碱性水溶液进行表面水解改性。
另外，本公开还可以对所得到的改性后的聚合物初生膜进行后处理，所述后处理包括使用去离子水将其洗涤至中性，从而得到支撑层。
纳米过渡层的制备
在本公开中，通过将纤维素纳米晶体溶于第一溶剂中，得到纳米过渡层溶液。具体地，对于第一溶剂，本公开不作特别限定，可以为支撑层中使用的第一溶剂。具体地，其可以包括N,N-二甲基甲酰胺(DMF)、N,N-二甲基乙酰胺(DMAC)、N-甲基吡咯烷酮(NMP)、二甲基亚砜(DMSO)中的一种或两种组合。
在一些具体的实施方案中，在本公开中，在制备纳米过渡层溶液时，纤维素纳米晶体与第一溶剂的质量比可以为1:80～120，例如：1:85、1:90、1:95、1:100、1:105、1:110、1:115等。进一步地，为了使纳米过渡层与支撑层能够更好的结合，在制备纳米过渡层溶液时，可以加入催化剂，以使纳米过渡层中的纤维素纳米晶体与支撑层表面的活性基团更好的发生化学反应，以产生共价键。
具体地，所述催化剂为N,N-二环己基碳二亚胺(DCC)、N,N-二异丙基 碳二亚胺、1-环己基-2-吗啉己基碳二亚胺对甲苯磺酸盐、4-二甲氨基吡啶(DMAP)、2-氨基吡啶、2-羟乙基吡啶，3,4-而氨基吡啶中的一种或两种以上的组合。优选地，在制备纳米过渡层溶液中，所使用的催化剂为N,N-二环己基碳二亚胺(DCC)和4-二甲氨基吡啶(DMAP)。对于催化剂的加入量，本公开不作特别限定，可以是本领域常用的加入量。
进一步，可以将纤维素纳米晶体与催化剂加入第一溶剂中进行超声分散，超声分散的时间可以是5min～20min，从而得到混合均匀的CNC-DMF溶液。另外，在制备纳米过渡层溶液时，可以是在一定温度下进行的，作为优选，该温度可以是25℃～80℃，例如：30℃、35℃、40℃、45℃、50℃、55℃、60℃、65℃、70℃等。
进一步，使所述纳米过渡层溶液在所述支撑层的表面形成纳米过渡层膜，得到中间产物。
在一些具体的实施方案中，可以将支撑层浸入纳米过渡层溶液中，从而使得所述纳米过渡层膜形成于所述支撑层的表面。作为优选，在将支撑层浸入过渡层之前，可以除去其表面的残留溶液，例如，采用干燥或擦拭的方式除去表面的残留溶液。具体地，除去支撑层的表面残留溶液后浸入过渡层溶液中10min～30min，例如：15min、20min、25min等；然后再取出除去残留溶液，得到中间产物。
在一些具体的实施方案中，对所述中间产物的具有所述纳米过渡层膜的位置进行功能化处理，得到纳米过渡层。具体地，使用功能化溶液进行所述功能化处理，所述功能化溶液包括第一功能化溶液和第二功能化溶液；其中，所述第一功能化溶液包含交联剂；所述第二功能化溶液包含胺单体。
具体可以将中间产物浸入第一功能化溶液中10min～60min，例如：20min、30min、40min、50min等，然后取出除去表面残留溶液，接着浸入第二功能化溶液中10min～60min，例如：20min、30min、40min、50min等，然后取出用去离子水冲洗得到纳米过渡层。
纳米过渡层经功能化处理后为界面聚合提供了高密度的反应位点，消除 了基膜缺陷和油相酰氯水解的影响，促进生成无聚集孔的高交联度、超薄聚酰胺脱盐层，所制备得到的反渗透膜具有高通量和高脱盐率的同时具有更高的脱硼率。另一方面，高度功能化赋予了纤维素纳米晶体及其衍生物很强的硼捕获能力，阻碍了硼的渗透而进一步提升了层叠装载界面聚合复合反渗透膜的脱硼性能。其具有解决现有技术上的反渗透膜脱硼性能低的特征。
对于第一功能化溶液，具体可以将交联剂溶于第二溶剂中，以获取第一功能化溶液。具体地，所述交联剂可以是丙烯酸甲酯(MA)、甲基丙烯酸酯、甲基丙烯酸甲酯、丙烯酸丁酯、甲基丙烯酸乙酯等中一种或两种以上的组合。所述第二溶剂可以是四氢呋喃(THF)、丙酮、甲苯、苯甲醚、二氯甲烷等中的一种或两种以上的组合。
在一些具体的实施方案中，在本公开中，在制备第一功能化溶液时，交联剂与第二溶剂的质量比可以为1:1～10，优选为1:2～8，例如：1:3、1:4、1:5、1:6、1:7、1:9等。
进一步地，为了使纳米过渡层与胺单体能够更好的结合，在制备第一功能化溶液时，可以加入催化剂，以使纳米过渡层中的纤维素纳米晶体与胺单体更好的发生化学反应，以产生共价键。具体地，所述催化剂可以是α-溴异丁酰溴(BIB)、2,2-二溴甲基-1,3-二溴丙烷、二溴甲基苯、α,α-二溴化苄、α,α-二溴乙酸乙酯、α,α-二溴对二甲苯等中一种或两种以上组合。对于催化剂的加入量，本公开不作特定限定，可以是本领域常用加入量。
具体地，第一功能化溶液的制备方法可以是将交联剂和催化剂依次加入第二溶剂中混合均匀，得到第一功能化溶液备用。另外，在制备第一功能化溶液时，可以是在一定温度下进行的，作为优选，该温度可以是50～80℃，例如：55℃、60℃、65℃、70℃、75℃等。
对于第二功能化溶液，具体可以将胺单体溶于第二溶剂中，以获取第二功能化溶液。具体地，所述胺单体可以是间苯二胺、邻苯二胺、对苯二胺等中的一种或两种以上的组合，所述第二溶剂可以是四氢呋喃(THF)、丙酮、甲苯、苯甲醚、二氯甲烷等中的一种或两种以上的组合。
在一些具体的实施方案中，在本公开中，在制备第二功能化溶液时，胺单体与第二溶剂的质量比可以为1:5～20，优选为1:7～15，例如：1:6、1:8、1:9、1:10、1:11、1:12、1:14、、1:16、1:18、1:19等。
进一步地，为了使过渡层与胺单体能够更好的结合，在制备第二功能化溶液时，可以加入催化剂，以使过渡层中的纤维素纳米晶体与胺单体更好的发生化学反应，以产生共价键。具体地，所述催化剂可以是四正丁基溴化铵(TBAB)、三乙基苄基氯化胺、十二烷基三甲基溴化铵、十六烷基三甲基溴化铵、十二烷基三甲基氯化铵等中的一种或两种以上的组合。对于催化剂的加入量，本公开不作特具体限定，可以是本领域常用的加入量。
具体地，第二功能化溶液的制备方法可以是将胺单体和催化剂依次加入第二溶剂中混合均匀，得到第二功能化溶液备用。另外，在制备第二功能化溶液时，可以是在一定温度下进行的，作为优选，该温度可以是50-80℃，例如：55℃、60℃、65℃、70℃、75℃等。
脱盐层的制备
本公开的脱盐层可以是直接在所述纳米过渡层的表面形成。
在一些具体的实施方案中，可以利用油相单体溶液和第二功能化溶液中的所述胺单体形成所述脱盐层。具体地，可以将得到的上述形成有纳米过渡层的支撑层浸渍于油相单体溶液和保湿剂溶液中，得到脱硼反渗透膜。其中，对于在油相单体溶液和保湿剂溶液中浸渍的先后顺序，本公开不作特别限定，可以先浸渍于保湿剂溶液中，也可先浸渍于油相单体溶液中。优选地，可以先浸渍于油相单体溶液中，再浸渍于保湿剂溶液中。
具体地，可以先将膜片浸渍于所述油相单体溶液中，浸渍时间不宜过长。一般而言，浸渍于油相单体溶液中的时间可以为30s～60s，例如：35s、40s、45s、50s、55s等；然后利用酸性溶液清洗油相浸渍产物及残留溶液，清洗的时间为3min～6min；最后再浸渍于所述保湿剂溶液中，浸渍于保湿剂溶液中的时间可以为3min～6min，例如4min、5min等。取出后干燥，可以得到脱硼反渗透膜，干燥的温度可以为50℃～90℃，优选为70℃～80℃，例如：55℃、 60℃、65℃、70℃、75℃、85℃等。
进一步，对于油相单体溶液，可以是将油相活性单体溶于第三溶剂中，从而获得油相单体溶液。具体地，所述油相活性单体为对苯二甲酰氯、间苯二甲酰氯、邻苯二甲酰氯、环己三甲酰氯、均苯三甲酰氯、戊二酰氯的一种或两种以上的组合。所述第三溶剂可以是常用的有机溶剂，例如：正己烷、环己烷、正庚烷、甲苯、三氯甲烷、isopar G等中的一种或两种以上的组合。
在一些具体的实施方案中，所述油相单体溶液中，以所述油相单体溶液的总质量计，油相活性单体的浓度为0.05wt％～3.0wt％，所述第三溶剂的加入量为97wt％～99.95wt％。具体地，所述油相单体的加入量可以为0.5wt％、1wt％、1.5wt％、2wt％、2.5wt％、2.8wt％等；所述第三溶剂的加入量可以为97.2wt％、97.5wt％、98wt％、98.5wt％、99wt％、99.5wt％等。
另外，对于清洗过程中使用的酸性溶液，其可以是盐酸物质溶于水中，其中，以所述酸性溶液的总质量计，酸性物质的浓度可以是0.5wt～3.0wt％。作为优选，所述酸性物质为氯化氢。
进一步，对于保湿剂溶液，可以是将保湿剂溶于第四溶剂中，从而获得保湿剂溶液。具体地，所述保湿剂为甘油、苯乙醇、甘油单乙酸酯、异丙醇、甘露醇中的一种或两种以上的组合。所述第四溶剂可以是常用的水相溶剂，例如：去离子水等。
在一些具体的实施方案中，所述保湿剂溶液中，以所述保湿剂溶液的总质量计，保湿剂的浓度为5wt％～15.0wt％，例如：7wt％、9wt％、11wt％、13wt％、14wt％等；所述第四溶剂的加入量为85wt％～95wt％；例如：86wt％、87wt％、89wt％、91wt％、93wt％等。
实施例
下面将结合实施例对本公开的实施方案进行详细描述，但是本领域技术人员将会理解，下列实施例仅用于说明本公开，而不应视为限定本公开的范围。实施例中未注明具体条件者，按照常规条件或制造商建议的条件进行。所用试剂或仪器未注明生产厂商者，均为可以通过市售获得的常规产品。
实施例1
(1)纤维素纳米晶体溶液的制备：将纤维素纳米晶体(CNC)和N,N-二甲基甲酰胺(DMF)按质量比1:100混合，加入催化剂N,N-二环己基碳二亚胺(DCC)和4-二甲氨基吡啶(DMAP)进行超声分散10min得到混合均匀的CNC-DMF溶液，并加热至70℃备用；
(2)纳米过渡层功能化溶液的制备：将交联剂丙烯酸甲酯(MA)和四氢呋喃(THF)按质量比4:1混合，并加入催化剂α-溴异丁酰溴(BIB)搅拌混合均匀，得到功能化溶液①，加热至70℃备用。将间苯二胺和四氢呋喃(THF)按质量比1:10混合，并加入催化剂四正丁基溴化铵(TBAB)搅拌混合均匀，得到功能化溶液②，加热至70℃备用；
(3)支撑层的制备：将0.1wt％聚乙烯吡咯烷酮加入处于搅拌状态的N,N-二甲基甲酰胺(DMF)中进行混合分散，维持搅拌状态升温至70℃，向其中加入15.0wt％的聚丙烯腈，剩余部分由N,N-二甲基甲酰胺(DMF)补充至100wt％，得到聚合物均相溶液。再在-80kPa下进行真空脱泡处理后过滤，冷却至室温，采用刮刀系统均匀涂布在无纺布基材上，再将其浸入15℃的去离子水凝固浴中处理300s后，获得聚丙烯腈(PAN)初生膜。将聚丙烯腈(PAN)初生膜浸入40℃的5.0wt％氢氧化钠溶液中进行表面水解改性，30min后取出用去离子清洗至中性，得到HPAN支撑层；
(4)支撑层装载纤维素纳米晶体过渡层：除去步骤(3)所得HPAN支撑层的表面残留溶液后浸入步骤(1)所制70℃溶液中20min后，取出除去残留溶液，得到HAPN-CNC膜；
(5)纤维素纳米晶体过渡层的功能化：将步骤(4)所得的HPAN-CNC膜浸入步骤(2)所制70℃的溶液①中30min后，取出除去表面残留溶液，接着浸入步骤(2)所制70℃的溶液②中30min后，取出用去离子水冲洗得到胺单体装载的HPAN-CNC-a膜；
(6)脱盐层的制备：将步骤(5)所制HPAN-CNC-a膜浸入以正己烷为溶剂，并含有0.05wt％对苯二甲酰氯的油相溶液中30s后，取出去除表面残留的正己烷溶液，并用2.0wt％稀盐酸清洗5min，再浸入8.0wt％甘油水溶液中浸润5min，取出放入50℃烘箱中烘干，即制得层叠装载界面聚合脱硼反渗透膜LIP-SWRO-1。
实施例1中，所述纤维素纳米晶体的直径为5nm，长度为50nm；所述无纺布基材的材质为聚丙烯(PP)。
实施例2
(1)纤维素纳米晶体溶液的制备：将纤维素纳米晶体(CNC)和N,N-二甲基甲酰胺(DMF)按质量比1:100混合，加入催化剂N,N-二环己基碳二亚胺(DCC)和4-二甲氨基吡啶(DMAP)进行超声分散10min得到混合均匀的CNC-DMF溶液，并加热至70℃备用；
(2)纳米过渡层功能化溶液的制备：将交联剂丙烯酸甲酯(MA)和四氢呋喃(THF)按质量比4:1混合，并加入催化剂α-溴异丁酰溴(BIB)搅拌混合均匀，得到功能化溶液①，加热至70℃备用。将间苯二胺和四氢呋喃(THF)按质量比1:10混合，并加入催化剂四正丁基溴化铵(TBAB)搅拌混合均匀，得到功能化溶液②，加热至70℃备用；
(3)支撑层的制备：将1.0wt％聚乙烯吡咯烷酮加入处于搅拌状态的N,N-二甲基甲酰胺(DMF)中进行混合分散，维持搅拌状态升温至70℃，向其中加入16.0wt％的聚丙烯腈，剩余部分由N,N-二甲基甲酰胺(DMF)补充至100wt％，得到聚合物均相溶液。再在-80kPa下进行真空脱泡处理后过滤，冷却至室温，采用刮刀系统均匀涂布在无纺布基材上，再将其浸入18℃的去离子水凝固浴中处理300s后，获得聚丙烯腈(PAN)初生膜。将聚丙烯腈(PAN)初生膜浸入50℃的5.0wt％氢氧化钠溶液中进行表面水解改性，30min后取出用去离子清洗至中性，得到HPAN支撑层；
(4)支撑层装载纤维素纳米晶体过渡层：除去步骤(3)所得HPAN支撑层的表面残留溶液后浸入步骤(1)所制70℃溶液中15min后，取出除去残留溶液，得到HAPN-CNC膜；
(5)纤维素纳米晶体过渡层的功能化：将步骤(4)所得的HPAN-CNC膜浸入步骤(2)所制70℃溶液①中40min后，取出除去表面残留溶液，接着浸入步骤(2)所制70℃溶液②中30min后，取出用去离子水冲洗得到胺单体装载HPAN-CNC-a膜；
(6)脱盐层的制备：将步骤(5)所制HPAN-CNC-a膜浸入以环己烷为溶剂，并含有0.5wt％间苯二甲酰氯的油相溶液中40s后，取出除去表面残留的环己烷溶液，并用2.0wt％稀盐酸清洗5min，再浸入8.0wt％甘油水溶液中浸润5min，取出放入60℃烘箱中烘干，即可制得层叠装载界面聚合高脱硼海水淡化反渗透膜LIP-SWRO-2。
实施例2中，所述纤维素纳米晶体的直径为10nm，长度为50nm；所述无纺布基材的材质为聚丙烯(PP)。
实施例3
(1)纤维素纳米晶体溶液的制备：将纤维素纳米晶体(CNC)和N,N-二甲基甲酰胺(DMF)按质量比1:100混合，加入催化剂N,N-二环己基碳二亚胺(DCC)和4-二甲氨基吡啶(DMAP)进行超声分散10min得到混合均匀的CNC-DMF溶液，并加热至70℃备用；
(2)纳米过渡层功能化溶液的制备：将交联剂丙烯酸甲酯(MA)和四氢呋喃(THF)按质量比4:1混合，并加入催化剂α-溴异丁酰溴(BIB)搅拌混合均匀，得到功能化溶液①，加热至70℃备用。将间苯二胺和四氢呋喃(THF)按质量比1:10混合，并加入催化剂四正丁基溴化铵(TBAB)搅拌混合均匀，得到功能化溶液②，加热至70℃备用；
(3)支撑层的制备：将1.5wt％聚乙烯吡咯烷酮加入处于搅拌状态的N,N- 二甲基甲酰胺(DMF)中进行混合分散，维持搅拌状态升温至70℃，向其中加入18.0wt％的聚丙烯腈，剩余部分由N,N-二甲基甲酰胺(DMF)补充至100wt％，得到聚合物均相溶液。再在-80kPa下进行真空脱泡处理后过滤，冷却至室温，采用刮刀系统均匀涂布在无纺布基材上，再将其浸入20℃的去离子水凝固浴中处理300s后，获得聚丙烯腈(PAN)初生膜。将聚丙烯腈(PAN)初生膜浸入60℃的5.0wt％氢氧化钠溶液中进行表面水解改性，30min后取出用去离子清洗至中性，得到HPAN支撑层；
(4)支撑层装载纤维素纳米晶体过渡层：除去步骤(3)所得HPAN支撑层的表面残留溶液后浸入步骤(1)所制70℃溶液中25min后，取出除去残留溶液，得到HAPN-CNC膜；
(5)纤维素纳米晶体过渡层的功能化：将步骤(4)所得的HPAN-CNC膜浸入步骤(2)所制70℃溶液①中35min后，取出除去表面残留溶液，接着浸入步骤(2)所制70℃溶液②中20min后，取出用去离子水冲洗得到胺单体装载HPAN-CNC-a膜；
(6)脱盐层的制备：将步骤(5)所制HPAN-CNC-a膜浸入以正庚烷为溶剂，并含有1.0wt％邻苯二甲酰氯的油相溶液中45s后，取出除去表面残留的正庚烷溶液，并用2.0wt％稀盐酸清洗5min，再浸入8.0wt％甘油水溶液中浸润5min，取出放入70℃烘箱中烘干，即可制得层叠装载界面聚合高脱硼海水淡化反渗透膜LIP-SWRO-3。
实施例3中，所述纤维素纳米晶体的直径为10nm，长度为100nm；所述无纺布基材的材质为聚丙烯(PP)。
实施例4
(1)纤维素纳米晶体溶液的制备：将纤维素纳米晶体(CNC)和N,N-二甲基甲酰胺(DMF)按质量比1:100混合，加入催化剂N,N-二环己基碳二亚胺(DCC)和4-二甲氨基吡啶(DMAP)进行超声分散10min得到混合均 匀的CNC-DMF溶液，并加热至70℃备用；
(2)纳米过渡层功能化溶液的制备：将交联剂MA和四氢呋喃(THF)按质量比4:1混合，并加入催化剂α-溴异丁酰溴(BIB)搅拌混合均匀，得到功能化溶液①，加热至70℃备用。将间苯二胺和THF按质量比1:10混合，并加入催化剂四正丁基溴化铵(TBAB)搅拌混合均匀，得到功能化溶液②，加热至70℃备用；
(3)支撑层的制备：将3.0wt％聚乙烯吡咯烷酮加入处于搅拌状态的N,N-二甲基甲酰胺(DMF)中进行混合分散，维持搅拌状态升温至70℃，向其中加入19.0wt％的聚丙烯腈，剩余部分由N,N-二甲基甲酰胺(DMF)补充至100wt％，得到聚合物均相溶液。再在-80kPa下进行真空脱泡处理后过滤，冷却至室温，采用刮刀系统均匀涂布在无纺布基材上，再将其浸入20℃的去离子水凝固浴中处理300s后，获得聚丙烯腈(PAN)初生膜。将聚丙烯腈(PAN)初生膜浸入70℃的5.0wt％氢氧化钠溶液中进行表面水解改性，30min后取出用去离子清洗至中性，得到HPAN支撑层；
(4)支撑层装载纤维素纳米晶体过渡层：除去步骤(3)所得HPAN支撑层的表面残留溶液后浸入步骤(1)所制70℃溶液中15min后，取出除去残留溶液，得到HAPN-CNC膜；
(5)纤维素纳米晶体过渡层的功能化：将步骤(4)所得的HPAN-CNC膜浸入步骤(2)所制70℃溶液①中45min后，取出除去表面残留溶液，接着浸入步骤(2)所制70℃溶液②中25min后，取出用去离子水冲洗得到胺单体装载HPAN-CNC-a膜；
(6)脱盐层的制备：将步骤(5)所制HPAN-CNC-a膜浸入以甲苯为溶剂，并含有2.0wt％环己三甲酰氯的油相溶液中50s后，取出除去表面残留的甲苯溶液，并用2.0wt％稀盐酸清洗5min，再浸入8.0wt％甘油水溶液中浸润5min，取出放入80℃烘箱中烘干，即可制得层叠装载界面聚合高脱硼海水淡 化反渗透膜LIP-SWRO-4。
实施例4中，所述纤维素纳米晶体的直径为10nm，长度为200nm；所述无纺布基材的材质为聚丙烯(PP)。
实施例5
(1)纤维素纳米晶体溶液的制备：将纤维素纳米晶体(CNC)和N,N-二甲基甲酰胺(DMF)按质量比1:100混合，加入催化剂N,N-二环己基碳二亚胺(DCC)和4-二甲氨基吡啶(DMAP)进行超声分散10min得到混合均匀的CNC-DMF溶液，并加热至70℃备用；
(2)纳米过渡层功能化溶液的制备：将交联剂MA和四氢呋喃(THF)按质量比4:1混合，并加入催化剂α-溴异丁酰溴(BIB)搅拌混合均匀，得到功能化溶液①，加热至70℃备用。将间苯二胺和四氢呋喃(THF)按质量比1:10混合，并加入催化剂四正丁基溴化铵(TBAB)搅拌混合均匀，得到功能化溶液②，加热至70℃备用；
(3)支撑层的制备：将5.0wt％聚乙烯吡咯烷酮加入处于搅拌状态的N,N-二甲基甲酰胺(DMF)中进行混合分散，维持搅拌状态升温至70℃，向其中加入20.0wt％的聚丙烯腈，剩余部分由N,N-二甲基甲酰胺(DMF)补充至100wt％，得到聚合物均相溶液。再在-80kPa下进行真空脱泡处理后过滤，冷却至室温，采用刮刀系统均匀涂布在无纺布基材上，再将其浸入18℃的去离子水凝固浴中处理300s后，获得聚丙烯腈(PAN)初生膜。将聚丙烯腈(PAN)初生膜浸入80℃的5.0wt％氢氧化钠溶液中进行表面水解改性，30min后取出用去离子清洗至中性，得到HPAN支撑层；
(4)支撑层装载纤维素纳米晶体过渡层：除去步骤(3)所得HPAN支撑层的表面残留溶液后浸入步骤(1)所制70℃溶液中20min后，取出除去残留溶液，得到HAPN-CNC膜；
(5)纤维素纳米晶体过渡层的功能化：将步骤(4)所得的HPAN-CNC膜浸入步骤(2)所制70℃溶液①中25min后，取出除去表面残留溶液，接着 浸入步骤(2)所制70℃溶液②中40min后，取出用去离子水冲洗得到胺单体装载HPAN-CNC-a膜；
(6)脱盐层的制备：将步骤(5)所制HPAN-CNC-a膜浸入以isopar G为溶剂，并含有3.0wt％均苯三甲酰氯的油相溶液中60s后，取出除去表面残留的isopar G溶液，并用2.0wt％稀盐酸清洗5min，再浸入8.0wt％甘油水溶液中浸润5min，取出放入90℃烘箱中烘干，即可制得层叠装载界面聚合高脱硼海水淡化反渗透膜LIP-SWRO-5。
实施例5中，所述纤维素纳米晶体的直径为15nm，长度为300nm；所述无纺布基材的材质为聚丙烯(PP)。
对比例1
(1)支撑层的制备：将5.0wt％聚乙烯吡咯烷酮加入处于搅拌状态的N,N-二甲基甲酰胺(DMF)中进行混合分散，维持搅拌状态升温至70℃，向其中加入18.0wt％的聚丙烯腈，剩余部分由N,N-二甲基甲酰胺(DMF)补充至100wt％，得到聚合物均相溶液。再在-80kPa下进行真空脱泡处理后过滤，冷却至室温，采用刮刀系统均匀涂布在无纺布基材上，再将其浸入15℃的去离子水凝固浴中处理300s后，获得多孔支撑层。
(2)脱盐层的制备：将步骤(1)所制多孔支撑层浸入3.0wt％间苯二胺水溶液中60s后，取出除去表面残留的水溶液；然后再浸入以正己烷为溶剂，并含有3.0wt％均苯三甲酰氯的油相溶液中40s后，取出除去表面残留的正己烷溶液，并用2.0wt％稀盐酸清洗5min，再浸入8.0wt％甘油水溶液中浸润5min，取出放入90℃烘箱中烘干，即可制得SWRO反渗透膜。
对比例1中，所述无纺布基材的材质为聚丙烯(PP)。
性能测试
取实施例1～5中制备的脱硼反渗透膜LIP-SWRO-1、LIP-SWRO-2、LIP-SWRO-3、LIP-SWRO-4和LIP-SWRO-5，以及对比例1中的SWRO反渗透膜，放在高压膜片检测台测试。在操作压力为800psi、原水为32000±1000ppm氯化钠和5±0.5ppm硼酸水溶液、溶液温度为25℃、pH值为6.5～7.5的测试条 件下，运行30min后测试反渗透膜片的水通量、脱盐率和脱硼率，结果如表1所示。
表1
Figure PCTCN2021135768-appb-000001
由表1可以看出，实施例1～5的脱硼反渗透膜的水通量、脱盐率均以及脱硼率均非常优异。因此，本申请的实施例1～5的脱硼反渗透膜与对比例1的反渗透膜相比，本申请的实施例1～5的脱硼反渗透膜在具有相当通量和高脱盐率的同时具有更高的脱硼率。
需要说明的是，尽管以具体实施例介绍了本公开的技术方案，但本领域技术人员能够理解，本公开应不限于此。
以上已经描述了本公开的各实施例，上述说明是示例性的，并非穷尽性的，并且也不限于所披露的各实施例。在不偏离所说明的各实施例的范围和精神的情况下，对于本技术领域的普通技术人员来说许多修改和变更都是显而易见的。本文中所用术语的选择，旨在最好地解释各实施例的原理、实际应用或对市场中的技术改进，或者使本技术领域的其它普通技术人员能理解本文披露的各实施例。

Claims (10)

  1. 一种脱硼反渗透膜，其特征在于，包括：
    支撑层，所述支撑层形成于基材的一个表面，所述支撑层包含有聚合物和成孔剂，且所述支撑层具有多孔结构；
    脱盐层，所述脱盐层包含有聚酰胺；以及
    纳米过渡层，所述纳米过渡层位于支撑层和脱盐层之间，且与所述支撑层和脱盐层相接触；其中，所述纳米过渡层包含有纤维素纳米晶体。
  2. 根据权利要求1所述的脱硼反渗透膜，其特征在于，所述纳米过渡层通过共价键形成于所述支撑层的表面；
    所述脱盐层通过共价键叠加在所述纳米过渡层的与所述支撑层相对的一面。
  3. 根据权利要求1或2所述的脱硼反渗透膜，其特征在于，所述聚合物包括聚丙烯腈，或聚丙烯腈与选自聚砜、聚醚砜、聚氯乙烯、聚醚醚酮中的一种或两种以上的组合；和/或
    所述成孔剂包括高分子成孔剂或小分子成孔剂；优选地，所述高分子成孔剂包括聚乙二醇、聚乙烯吡咯烷酮或聚乙烯醇中的一种或两种以上的组合；所述小分子成孔剂包括氯化锂、氯化钙或水的一种或两种以上的组合。
  4. 根据权利要求1-3任一项所述的脱硼反渗透膜，其特征在于，所述支撑层为通过使用改性剂对其表面进行水解改性得到的支撑层；
    所述纳米过渡层为对其表面进行功能化处理得到的纳米过渡层。
  5. 根据权利要求1-4任一项所述的脱硼反渗透膜，其特征在于，所述纤维素纳米晶体的直径为5～15nm，优选5～10nm；所述纤维素纳米晶体的长度为50～300nm，优选为50～100nm。
  6. 一种根据权利要求1-5任一项所述的脱硼反渗透膜的制备方法，其特征在于，包括将支撑层、纳米过渡层以及脱盐层复合成型的步骤。
  7. 根据权利要求6所述的制备方法，其特征在于，包括以下步骤：
    将聚合物和成孔剂溶于第一溶剂中，得到支撑层溶液，然后使所述支撑层溶液在基材的一个表面成膜，得到支撑层；
    将纤维素纳米晶体溶于第一溶剂中，得到纳米过渡层溶液，使所述纳米过渡层溶液在所述支撑层的表面形成纳米过渡层膜，得到中间产物；
    对所述中间产物的具有所述纳米过渡层膜的位置进行功能化处理，得到纳米过渡层；
    在所述纳米过渡层的与所述支撑层相对的表面形成脱盐层，得到脱硼反渗透膜。
  8. 根据权利要求7所述的制备方法，其特征在于，所述制备方法还包括利用改性剂对所述支撑层的表面进行水解改性处理的步骤，优选地，所述改性剂包括碱剂。
  9. 根据权利要求7或8所述的制备方法，其特征在于，使用功能化溶液进行所述功能化处理，所述功能化溶液包括第一功能化溶液和所述第二功能化溶液；其中，
    所述第一功能化溶液包含交联剂；所述第二功能化溶液包含胺单体。
  10. 根据权利要求9所述的制备方法，其特征在于，利用油相单体溶液和所述胺单体形成所述脱盐层。
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