Polyester-based reverse osmosis membrane as well as preparation method and application thereof

Abstract

The invention provides a polyester-based reverse osmosis membrane as well as a preparation method and application thereof, the polyester-based reverse osmosis membrane comprises a polyester non-woven fabric, a polyester supporting layer and a polyamide functional layer which are arranged in sequence, and catalysts in preparation raw materials of the polyester non-woven fabric and the polyester supporting layer are non-antimony catalysts; the polyester non-woven fabric and the polyester supporting layer are matched, and catalysts in the preparation raw materials of the polyester non-woven fabric and the polyester supporting layer are limited to be non-antimony catalysts, so that the obtained polyester-based reverse osmosis membrane can be ensured to have relatively high desalination rate and very excellent separation performance; and the problem that bisphenol A and metal antimony are easy to separate out in the use process of a conventional reverse osmosis membrane can be effectively avoided, so that the obtained polyester-based reverse osmosis membrane completely eradicates dissolution of antimony and bisphenol A from the source, and the polyester-based reverse osmosis membrane is very safe and environment-friendly in use.

Description

Technical Field

[0001] The invention belongs to the technical field of reverse osmosis membranes, and in particular relates to a polyester-based reverse osmosis membrane and a preparation method and application thereof. Background Art

[0002] Reverse osmosis membrane (RO membrane) is an artificial semipermeable membrane with certain characteristics made by simulating biological semipermeable membrane. Its principle is to separate these substances and water under the action of osmotic pressure higher than that of the solution, based on the fact that other substances cannot pass through the semipermeable membrane; the pore size of the reverse osmosis membrane is very small, so it can effectively remove dissolved salts, colloids, microorganisms, organic matter, etc. in the water. It has the advantages of good water quality, low energy consumption, no pollution, simple process, easy operation, etc., and is often used to prepare water treatment components.

[0003] At present, conventional RO membranes are composed of non-woven fabrics, polysulfone support layers and ultra-thin separation layers. For example, CN113634141A discloses a method for preparing a polyamide composite reverse osmosis membrane, a reverse osmosis membrane and its application, wherein the method for preparing the reverse osmosis membrane comprises the following steps: a. dissolving polysulfone in N,N-dimethylformamide to obtain a casting solution, uniformly scraping the casting solution on a polyester non-woven fabric, and curing and forming the polysulfone support layer in water; b. dissolving m-phenylenediamine and chlorophyllin in deionized water to prepare an aqueous phase solution; dissolving trimesoyl chloride in an alkane solvent to prepare an organic phase solution; c. contacting the polysulfone support layer with the aqueous phase solution, removing the excess aqueous phase, and then contacting the polysulfone support layer with the organic phase solution to form a polyamide composite reverse osmosis membrane through interfacial polymerization; the reverse osmosis membrane prepared by the inventive method has a high permeation flux and anti-microbial contamination performance.

[0004] However, the non-woven fabrics used in conventional RO membranes, including the above-mentioned invention, are mostly made of PET. Antimony is often used as a catalyst in the synthesis process of PET, resulting in residual antimony in the PET non-woven fabric, which in turn causes antimony to dissolve out of the RO membrane during use. Antimony is toxic, and when a certain amount of antimony enters the human body, it can cause problems such as fatigue, headache, and sleep disorders. In severe cases, it can damage the nervous system, leading to blood diseases, developmental delay, and mental retardation. In addition, the polysulfone support layer used in conventional RO membranes is synthesized from bisphenol A and 4,4-dichlorodiphenyl sulfone through salt formation and condensation. The bisphenol A used can cause endocrine disorders, interfere with the reproductive system, and induce precocious puberty in children.

[0005] Therefore, in view of the fact that the existing conventional RO membrane cannot eliminate the problem of antimony and bisphenol A dissolution from the root, the present invention urgently needs to develop a polyester-based reverse osmosis membrane that does not contain antimony and bisphenol A and has excellent separation performance. Summary of the invention

[0006] In view of the deficiencies in the prior art, the object of the present invention is to provide a polyester-based reverse osmosis membrane and a preparation method and application thereof. The polyester-based reverse osmosis membrane is composed of a polyester non-woven fabric and a polyester support layer, and the catalysts in the preparation raw materials of the two are limited to non-antimony catalysts, thereby eliminating the problem of antimony and bisphenol A dissolution from the root. It is very safe and environmentally friendly, and also has a high desalination rate and excellent separation performance.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a polyester-based reverse osmosis membrane, wherein the polyester-based reverse osmosis membrane comprises a polyester non-woven fabric, a polyester support layer and a polyamide functional layer arranged in sequence;

[0009] Furthermore, the catalysts in the raw materials for preparing the polyester non-woven fabric and the polyester support layer are all non-antimony catalysts.

[0010] The polyester-based reverse osmosis membrane provided by the present invention comprises a polyester non-woven fabric, a polyester support layer and a polyamide functional layer which are arranged in sequence, and the catalysts in the raw materials for preparing the polyester non-woven fabric and the polyester support layer are all non-antimony catalysts; firstly, by selecting the polyester non-woven fabric and the polyester support layer for matching, not only can the obtained reverse osmosis membrane be guaranteed to have a high desalination rate and excellent separation performance, but also the problem of bisphenol A precipitation when the conventional reverse osmosis membrane uses a polysulfone support layer can be effectively avoided; secondly, by further limiting that the raw materials for preparing the polyester non-woven fabric and the polyester support layer do not include antimony catalysts, the problem of antimony dissolution is further eliminated from the root, so that the obtained polyester-based reverse osmosis membrane is very safe and environmentally friendly when used.

[0011] Preferably, the polyester nonwoven fabric has a thickness of 60 to 120 μm, for example, 60 μm, 70 μm, 80 μm, 90 μm, 100 μm, 110 μm or 120 μm.

[0012] Preferably, the thickness of the polyester support layer is 25-60 μm, for example, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, 50 μm, 55 μm or 60 μm.

[0013] Preferably, the thickness of the polyamide functional layer is 50 to 200 nm, for example, 50 nm, 70 nm, 90 nm, 110 nm, 130 nm, 150 nm, 170 nm, 190 nm or 200 nm.

[0014] Preferably, the polyester nonwoven fabric is obtained by heating the polyester resin A to be melted, and then mixing, extruding, casting, stretching and heat-setting.

[0015] Preferably, the number average molecular weight of the polyester resin A is 20,000 to 25,000, for example, 20,500, 21,000, 21,500, 22,000, 22,500, 23,000, 23,500, 24,000, 24,500 or 25,000.

[0016] Preferably, the polyester resin A is obtained by catalysis using a titanium catalyst A. By using the titanium catalyst A as a catalyst, the prepared polyester resin A does not contain antimony.

[0017] In the present invention, there is no special restriction on the source of the polyester resin A, as long as it is obtained by catalysis using a titanium catalyst A. It can be directly purchased from the market or made at home. If homemade is chosen, the subsequent preparation method of polyester resin B can be referred to.

[0018] Preferably, the melting temperature is 260-270°C, for example, 260°C, 262°C, 264°C, 266°C, 268°C or 270°C.

[0019] Preferably, the temperature of the casting sheet is 10-35°C, for example, any one of 10°C, 12°C, 14°C, 16°C, 18°C, 20°C, 22°C, 24°C or 25°C, or a combination of at least two thereof.

[0020] Preferably, the stretching includes transverse stretching and longitudinal stretching.

[0021] Preferably, the heat setting temperature is 230-250°C, for example, 230°C, 232°C, 234°C, 236°C, 238°C, 240°C, 242°C, 244°C, 246°C, 248°C or 250°C.

[0022] Preferably, the heat setting further comprises the steps of cleaning and drying.

[0023] Preferably, the polyester non-woven fabric is prepared by the following method, which includes: heating the polyester resin A to 260-270°C for melting, mixing and extruding it into an extruder, casting it on a cold drum at 10-35°C, stretching it in a longitudinal stretching machine and a transverse stretching machine respectively, then heat-setting it at 230-250°C, then soaking and washing it in hot water at 45-80°C, and finally drying it in an oven at 25-35°C to obtain the polyester non-woven fabric.

[0024] Preferably, the raw material for preparing the polyester support layer includes polyester resin B.

[0025] Preferably, the number average molecular weight of the polyester resin B is 15000-25000, for example, 15000, 17000, 19000, 21000, 23000 or 25000.

[0026] Preferably, the raw materials for preparing the polyester resin B include the following components in parts by weight:

[0027]

[0028] Wherein, the amount of ethylene glycol used can be 320 parts by weight, 325 parts by weight, 330 parts by weight, 335 parts by weight or 340 parts by weight, etc.

[0029] The amount of the titanium catalyst B can be 0.2 parts by weight, 0.25 parts by weight, 0.3 parts by weight, 0.35 parts by weight, 0.4 parts by weight, 0.45 parts by weight or 0.5 parts by weight.

[0030] The amount of the stabilizer can be 0.5 parts by weight, 0.6 parts by weight, 0.7 parts by weight, 0.8 parts by weight, 0.9 parts by weight or 1 part by weight, etc.

[0031] The matting agent may be used in an amount of 5 parts by weight, 5.5 parts by weight, 6 parts by weight, 6.5 parts by weight, 7 parts by weight, 7.5 parts by weight or 8 parts by weight.

[0032] The amount of the inorganic nanomaterial can be 15 parts by weight, 20 parts by weight, 25 parts by weight, 30 parts by weight, 35 parts by weight or 40 parts by weight.

[0033] Preferably, the stabilizer includes any one of trimethyl phosphate, triethyl phosphate, triphenyl phosphate or tributyl phosphate, or a combination of at least two thereof.

[0034] Preferably, the matting agent comprises titanium dioxide.

[0035] Preferably, the inorganic nanomaterial includes any one or a combination of at least two of zinc oxide, hydrophobic silica, hydrophilic silica, calcium carbonate, talc, silver oxide, zirconium oxide or titanium oxide.

[0036] Preferably, the polyester resin B is prepared by the following method, which comprises: subjecting terephthalic acid, ethylene glycol, a titanium catalyst, a matting agent and a stabilizer to esterification and polycondensation, adding inorganic nanomaterials for mixing, cooling and granulating to obtain the polyester resin B.

[0037] Preferably, the temperature of the esterification reaction is 200-230°C, for example, 200°C, 205°C, 210°C, 215°C, 220°C, 225°C or 230°C.

[0038] Preferably, the esterification reaction time is 2 to 3 h, for example, 2 h, 2.2 h, 2.4 h, 2.6 h, 2.8 h or 3 h.

[0039] Preferably, the temperature of the polycondensation reaction is 275-285°C, for example, 275°C, 277°C, 279°C, 281°C, 283°C or 285°C.

[0040] Preferably, the polycondensation reaction time is 0.5 to 1.5 h, for example, 0.5 h, 0.7 h, 0.9 h, 1.1 h, 1.3 h or 1.5 h.

[0041] Preferably, the mixing time is 20 to 40 min, for example, 20 min, 22 min, 24 min, 26 min, 28 min, 30 min, 32 min, 34 min, 36 min, 38 min or 40 min.

[0042] Preferably, the titanium catalyst A and the titanium catalyst B each independently include C-94 catalyst-titanium / silicon oxide copolymer, tetramethylphenol titanium (IV), tri(dioctyl phosphate-O") isopropanol titanium, dihydroxybis(hydrogen lactic acid) titanium (IV), bis[2-[(2-aminoethyl)amino-κN]ethanol radical-κO][2-[(2-aminoethyl)amino]ethanol radical-κO](2-propanol radical) titanium, oxo[5,10,15,20-tetra(4-pyridyl)porphine] titanium Any one or a combination of at least two of titanium dioxide, titanium bis(2,4-pentanedione)trioxide, titanium tetra(2,4-pentanedione)trioxide, titanium bis(2-hydroxypropionic acid)diammonium dihydroxide, titanium tetra(2-ethyl-1,3-hexanediol), titanium tetrachlorobis(tetrahydrofuran), (OC-6-11)hexafluorotitanate(2-)potassium, dihydroxybis(hydrogen lactate)trioxide, phthalate compounds or phthalate chelates.

[0043] Preferably, the raw materials for preparing the polyamide functional layer include oil phase monomers and water phase monomers.

[0044] Preferably, the oil phase monomers include isophthaloyl chloride and / or trimesoyl chloride.

[0045] Preferably, the aqueous phase monomer comprises meta-phenylenediamine and / or iso-phenylenediamine.

[0046] In a second aspect, the present invention provides a method for preparing the polyester-based reverse osmosis membrane as described in the first aspect, the preparation method comprising: sequentially forming a polyester support layer and a polyamide functional layer on one side surface of a polyester non-woven fabric to obtain the polyester-based reverse osmosis membrane.

[0047] Preferably, the preparation method specifically comprises the following steps:

[0048] (1) forming a polyester support layer on one surface of the polyester nonwoven fabric by a solvent phase conversion method;

[0049] (2) forming a polyamide functional layer on the other side surface of the polyester support layer by interfacial polymerization to obtain the polyester-based reverse osmosis membrane.

[0050] Preferably, the method for forming the polyester support layer in step (1) specifically comprises the following steps:

[0051] (1A) providing a casting solution for forming the polyester support layer;

[0052] (1B) The casting solution is coated on one surface of the polyester non-woven fabric and solidified to form the polyester support layer.

[0053] Preferably, the casting solution in step (1A) is obtained by mixing the polyester resin B and a solvent.

[0054] Preferably, the solid content of the casting solution in step (1A) is 12-20%, for example, 12%, 14%, 16%, 18% or 20%.

[0055] Preferably, the solvent includes any one of dimethylformamide, dimethylacetamide, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone or tetrahydrofuran, or a combination of at least two thereof.

[0056] Preferably, the curing in step (1B) is performed by immersing in a poor solvent to perform phase separation curing.

[0057] Preferably, the poor solvent includes any one of water, ethanol or isopropanol, or a combination of at least two of them.

[0058] Preferably, the method for forming the polyamide functional layer in step (2) specifically comprises the following steps:

[0059] (2A) mixing an aqueous phase monomer and water to obtain an aqueous phase solution; mixing an oil phase monomer and an organic solvent to obtain an oil phase solution;

[0060] (2B) contacting one side surface of the polyester support layer in the polyester non-woven fabric with an aqueous solution and then with an oil solution, and obtaining the polyester-based reverse osmosis membrane through interfacial polymerization.

[0061] Preferably, the mass percentage of the aqueous phase monomer in the aqueous phase solution of step (2A) is 0.8-3%, for example, 0.8%, 1%, 1.5%, 2%, 2.5% or 3%.

[0062] Preferably, the organic solvent in step (2A) comprises any one of n-hexane, n-decane, ethylcyclohexane or an isomeric alkane solvent, or a combination of at least two thereof.

[0063] Preferably, the mass percentage of the oil phase monomer in the oil phase solution in step (2A) is 0.06-0.3%, for example, 0.06%, 0.08%, 0.1%, 0.15%, 0.2%, 0.25% or 0.3%.

[0064] Preferably, the temperature of the interfacial polymerization in step (2B) is 25-45°C, for example, 25°C, 30°C, 35°C, 40°C or 45°C.

[0065] Preferably, the time of the interfacial polymerization in step (2B) is 10 to 60 s, for example, 10 s, 20 s, 30 s, 40 s, 50 s or 60 s.

[0066] In a third aspect, the present invention provides a use of the polyester-based reverse osmosis membrane as described in the first aspect in water treatment.

[0067] Compared with the prior art, the present invention has the following beneficial effects:

[0068] The polyester-based reverse osmosis membrane provided by the present invention comprises a polyester non-woven fabric, a polyester support layer and a polyamide functional layer which are arranged in sequence, and the catalysts in the raw materials for preparing the polyester non-woven fabric and the polyester support layer are all non-antimony catalysts; by selecting the polyester non-woven fabric and the polyester support layer for matching, and limiting the catalysts in the raw materials for preparing the two to be non-antimony catalysts, not only can the obtained polyester-based reverse osmosis membrane be ensured to have a high desalination rate and excellent separation performance, but also the problem of bisphenol A and metallic antimony being easily precipitated from conventional reverse osmosis membranes during use can be effectively avoided, so that the obtained polyester-based reverse osmosis membrane eliminates the dissolution of antimony and bisphenol A from the root, and is very safe and environmentally friendly when used. BRIEF DESCRIPTION OF THE DRAWINGS

[0069] Figure 1 A schematic diagram of the cross-sectional structure of a polyester reverse osmosis membrane provided in Example 1 of the present invention;

[0070] Among them, 1-polyester non-woven fabric, 2-polyester support layer, 3-polyamide functional layer. DETAILED DESCRIPTION

[0071] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0072] Unless otherwise specified, the raw materials involved in the following examples and comparative examples are conventional materials in the art and can be purchased from commercial products.

[0073] Preparation Example 1

[0074] A polyester resin B-1, whose number average molecular weight is 20000, is prepared by raw materials comprising the following components in parts by weight:

[0075]

[0076]

[0077] Among them, the titanium catalyst is specifically C-94 catalyst-titanium / silicon oxide copolymer (Acordis, Germany), the stabilizer is specifically trimethyl phosphate (Aladdin reagent), and the matting agent is specifically titanium dioxide (Aladdin reagent);

[0078] The preparation method of the polyester resin A-1 provided in this preparation example comprises: subjecting terephthalic acid, ethylene glycol, a titanium catalyst, a matting agent and a stabilizer to an esterification reaction at 220° C. for 2.5 hours, heating to 280° C. for a condensation reaction for 1 hour, adding zinc oxide and mixing for 30 minutes, terminating, cooling and granulating to obtain the polyester resin A-1.

[0079] Preparation Example 2

[0080] A polyester resin B-2, whose number average molecular weight is 15000, is prepared by raw materials comprising the following components in parts by weight:

[0081]

[0082] Among them, the titanium catalyst is specifically C-94 catalyst-titanium / silicon oxide copolymer (Acordis Company, Germany), the stabilizer is specifically triethyl phosphate (Aladdin reagent), and the matting agent is specifically titanium dioxide (Aladdin reagent);

[0083] The preparation method of the polyester resin A-2 provided in this preparation example comprises: subjecting terephthalic acid, ethylene glycol, a titanium catalyst, a matting agent and a stabilizer to an esterification reaction at 230° C. for 2 hours, heating to 285° C. for a condensation reaction for 0.5 hours, adding hydrophilic silica and mixing for 20 minutes, terminating, cooling and granulating to obtain the polyester resin.

[0084] Preparation Example 3

[0085] A polyester resin B-3, whose number average molecular weight is 24000, is prepared from the following raw materials in parts by weight:

[0086]

[0087] Among them, the titanium catalyst is specifically C-94 catalyst-titanium / silicon oxide copolymer (Acordis, Germany), the stabilizer is specifically triphenyl phosphate (Aladdin reagent), and the matting agent is specifically titanium dioxide (Aladdin reagent);

[0088] The preparation method of the polyester resin A-3 provided in this preparation example comprises: subjecting terephthalic acid, ethylene glycol, a titanium catalyst, a matting agent and a stabilizer to an esterification reaction at 205° C. for 2.8 hours, heating to 275° C. for a condensation reaction for 1.5 hours, adding calcium carbonate and mixing for 40 minutes, terminating, cooling and granulating to obtain the polyester resin.

[0089] Preparation Example 4

[0090] A polyester resin B-4, which differs from Preparation Example 1 in that zinc oxide is not added, and other substances, amounts and preparation methods are the same as those in Example 1.

[0091] Comparative Preparation Example 1

[0092] A polyester resin D-1, which differs from Preparation Example 1 in that antimony acetate is used to replace C-94 catalyst-titanium / silicon oxide copolymer as a catalyst, and other substances, amounts and preparation methods are the same as those in Example 1.

[0093] Example 1

[0094] A polyester-based reverse osmosis membrane, the cross-sectional structure diagram of which is shown in FIG. Figure 1 As shown, it includes a polyester non-woven fabric 1, a polyester support layer 2 and a polyamide functional layer 3 arranged in sequence;

[0095] The thickness of the polyester nonwoven fabric 1 is 100 μm, and the material includes polyester resin A (number average molecular weight is 25,000, purchased from DuPont, USA, brand FR530, and the catalyst used in its preparation is C-94 catalyst-titanium / silicon oxide copolymer);

[0096] The thickness of the polyester support layer 2 is 50 μm, and the material includes polyester resin B-1 (from Preparation Example 1);

[0097] The thickness of the polyamide functional layer 3 is 80 nm, and the material includes polyamide;

[0098] The method for preparing a polyester-based reverse osmosis membrane provided in this embodiment comprises the following steps:

[0099] (1) heating the polyester resin A to 265° C. to melt, mixing and extruding the polyester resin A into an extruder, casting the polyester resin into a sheet on a cold drum at 20° C., longitudinally stretching the polyester resin A and transversely stretching the polyester resin A, and then heat-setting the polyester resin at 245° C. After the heat setting, the polyester resin A is soaked and washed in hot water at 50° C., and finally dried in an oven at 30° C. to obtain a polyester nonwoven fabric.

[0100] (2) mixing the polyester material B-1 and dimethylformamide to obtain a casting solution with a mass percentage of 15%, coating the casting solution on one side of the polyester non-woven fabric, immersing the casting solution in water for phase separation and solidification, and taking the casting solution out to form the polyester support layer on the surface of the polyester non-woven fabric;

[0101] (3) mixing m-phenylenediamine and water to obtain a m-xylene solution with a mass percentage of 1%; mixing isophthaloyl chloride and isoparaffin Isopar L to obtain an isophthaloyl chloride solution with a mass percentage of 0.2%;

[0102] (4) contacting one side of the polyester support layer in the polyester non-woven fabric with an aqueous solution, draining excess water, and then contacting with an oil solution to perform interfacial polymerization at 30° C. for 30 seconds to obtain the polyester-based reverse osmosis membrane.

[0103] Example 2

[0104] A polyester-based reverse osmosis membrane, whose cross-sectional structure is the same as that of Example 1, and also comprises a polyester non-woven fabric, a polyester support layer and a polyamide functional layer arranged in sequence;

[0105] The thickness of the polyester nonwoven fabric is 80 μm, and the material includes polyester resin A (number average molecular weight is 25,000, purchased from DuPont, USA, brand FR530, and the catalyst used in its preparation is C-94 catalyst-titanium / silicon oxide copolymer;

[0106] The thickness of the polyester support layer is 30 μm, and the material includes polyester resin B-2 (from Preparation Example 2);

[0107] The thickness of the polyamide functional layer is 80 nm, and the material includes polyamide;

[0108] The method for preparing a polyester-based reverse osmosis membrane provided in this embodiment comprises the following steps:

[0109] (1) heating the polyester resin A to 260° C. to melt, mixing and extruding the polyester resin A into an extruder, casting the polyester resin into a sheet on a cold drum at 15° C., longitudinally stretching the polyester resin A and transversely stretching the polyester resin A, and then heat-setting the polyester resin at 245° C. After the heat setting, the polyester resin A is soaked and washed in hot water at 45° C., and finally dried in an oven at 28° C. to obtain a polyester nonwoven fabric.

[0110] (2) mixing the polyester material B-2 and dimethylacetamide to obtain a casting solution with a mass percentage of 13%, coating the casting solution on one surface of the polyester non-woven fabric, immersing the casting solution in water for phase separation and solidification, and taking the casting solution out to form the polyester support layer on the surface of the polyester non-woven fabric;

[0111] (3) mixing phenyltriamine and water to obtain a phenyltriamine solution with a mass percentage of 0.9%; mixing phthaloyl chloride and isoparaffin Isopar L to obtain a phthaloyl chloride solution with a mass percentage of 0.1%;

[0112] (4) contacting one side of the polyester support layer in the polyester non-woven fabric with an aqueous solution, draining excess water, and then contacting with an oil solution to perform interfacial polymerization at 28° C. for 50 seconds to obtain the polyester-based reverse osmosis membrane.

[0113] Example 3

[0114] A polyester-based reverse osmosis membrane, whose cross-sectional structure is the same as that of Example 1, and also comprises a polyester non-woven fabric, a polyester support layer and a polyamide functional layer arranged in sequence;

[0115] The thickness of the polyester nonwoven fabric is 110 μm, and the material includes polyester resin A (number average molecular weight is 25,000, purchased from DuPont, USA, brand FR530, and the catalyst used in its preparation is C-94 catalyst-titanium / silicon oxide copolymer;

[0116] The thickness of the polyester support layer is 50 μm, and the material includes polyester resin B-3 (from Preparation Example 3);

[0117] The thickness of the polyamide functional layer is 100 nm, and the material includes polyamide;

[0118] The method for preparing a polyester-based reverse osmosis membrane provided in this embodiment comprises the following steps:

[0119] (1) heating the polyester resin A to 270° C. to melt, mixing and extruding the polyester resin A into an extruder, casting the polyester resin into a sheet on a cold drum at 35° C., stretching the polyester resin longitudinally and transversely, and heat-setting the sheet at 245° C. After the sheet is formed, the sheet is soaked and washed in hot water at 75° C., and finally dried in an oven at 35° C. to obtain a polyester nonwoven fabric;

[0120] (2) the polyester material B-3 and dimethyl sulfoxide are mixed to obtain a casting solution with a mass percentage of 18%, and the casting solution is then coated on one surface of the polyester non-woven fabric, immersed in water for phase separation and solidification, and taken out to form the polyester support layer on the surface of the polyester non-woven fabric;

[0121] (3) mixing 2-phenyltriamine and water to obtain a 2.8% by weight 2-phenyltriamine solution; mixing 2-phenylphthaloyl chloride and isoparaffin Isopar L to obtain a 0.25% by weight 2-phenylphthaloyl chloride solution;

[0122] (4) contacting one side of the polyester support layer in the polyester non-woven fabric with an aqueous solution, draining excess water, and then contacting with an oil solution, and performing interfacial polymerization at 45° C. for 10 seconds to obtain the polyester-based reverse osmosis membrane.

[0123] Example 4

[0124] A polyester-based reverse osmosis membrane, which differs from Example 1 only in that the polyester resin B-1 provided in Preparation Example 1 is used to replace the polyester resin A with the brand FR530 purchased from the manufacturer DuPont of the United States as the material of the polyester non-woven fabric, and other substances, structures and preparation methods are the same as those in Example 1.

[0125] Example 5

[0126] A polyester-based reverse osmosis membrane, which differs from Example 1 only in that the polyester resin B-4 provided in Preparation Example 4 is used to replace the polyester resin B-1 provided in Preparation Example 1 as the material of the polyester support layer, and other substances, structures and preparation methods are the same as those in Example 1.

[0127] Comparative Example 1

[0128] A polyester-based reverse osmosis membrane, which differs from Example 1 only in that the polyester resin D-1 provided in Comparative Preparation Example 1 is used to replace the polyester resin A with the brand FR530 purchased from the manufacturer DuPont of the United States as the material of the polyester non-woven fabric, and other substances, structures and preparation methods are the same as those in Example 1.

[0129] Comparative Example 2

[0130] A polyester-based reverse osmosis membrane, which differs from Example 1 only in that the polyester resin D-1 provided in Comparative Preparation Example 1 is used to replace the polyester resin B-1 provided in Preparation Example 1 as the material of the polyester support layer, and other substances, structures and preparation methods are the same as those in Example 1.

[0131] Comparative Example 3

[0132] A reverse osmosis membrane, refer to Example 1 in CN113634141A.

[0133] Performance Test:

[0134] (1) Desalination rate: 500 mg / L NaCl solution, pressure of 100 psi, temperature of 25°C, pH of 6.5-7.0, run for 30 min, and calculate the conductivity removal rate based on an influent flow rate of 3 L / min; the desalination rate is calculated as follows:

[0135]

[0136] Where: R represents the desalination rate, kp represents the conductivity of the pure water outlet (μS / cm), and kf represents the conductivity of the test solution (μS / cm).

[0137] (2) Antimony dissolution rate: The sample was rinsed with pure water for 30 min and then calculated based on the specific surface area per 1000 cm 2 Add 1L of pure water (including the front and back sides), immerse the sample in dark places for 24±1h, with the ambient temperature at 25±5℃, and test the antimony dissolution amount in accordance with the "Safety Evaluation Standard for Drinking Water Distribution Equipment and Protective Materials".

[0138] (3) Dissolution rate of bisphenol A: The sample was rinsed with pure water for 30 min and then calculated based on the specific surface area per 1000 cm 2 Add 1L of pure water (including the front and back sides), immerse the sample in dark places for 24±1h at an ambient temperature of 25±5℃, and test the dissolution rate of bisphenol A in accordance with the Safety Evaluation Standard for Drinking Water Distribution Equipment and Protective Materials.

[0139] The reverse osmosis membranes provided in Examples 1 to 5 and Comparative Examples 1 to 3 were tested according to the above test method. The test results are shown in Table 1:

[0140] Table 1

[0141] Desalination rate / % Antimony dissolution / mg / L Bisphenol A dissolution / mg / L Example 1 98.5 Not detected Not detected Example 2 98 Not detected Not detected Example 3 99 Not detected Not detected Example 4 98.7 Not detected Not detected Example 5 98.8 Not detected Not detected Comparative Example 1 98.1 0.000276 Not detected Comparative Example 2 98.2 0.000326 Not detected Comparative Example 3 98.4 0.000426 0.005

[0142] From the data in Table 1, we can see that:

[0143] The polyester-based reverse osmosis membranes provided in Examples 1 to 5 have a desalination rate of up to 98.5 to 99%, and no antimony dissolution or bisphenol A dissolution is detected, and have excellent separation performance and safety in use;

[0144] Antimony was eluted in the reverse osmosis membranes provided in Comparative Examples 1 and 2, while bisphenol A and antimony were eluted in the reverse osmosis membrane provided in Comparative Example 3. Both of them cannot eliminate the problem of bisphenol A and metallic antimony being easily precipitated during use, and the safety of use is poor.

[0145] The applicant declares that the present invention illustrates a polyester-based reverse osmosis membrane and its preparation method and application through the above-mentioned embodiments, but the present invention is not limited to the above-mentioned process steps, that is, it does not mean that the present invention must rely on the above-mentioned process steps to be implemented. Those skilled in the art should understand that any improvement of the present invention, equivalent replacement of the raw materials selected by the present invention, addition of auxiliary components, selection of specific methods, etc., all fall within the protection scope and disclosure scope of the present invention.

Claims

1. A polyester-based reverse osmosis membrane, characterized in that: The polyester-based reverse osmosis membrane comprises a polyester non-woven fabric, a polyester support layer and a polyamide functional layer arranged in sequence; Furthermore, the catalysts in the raw materials for preparing the polyester non-woven fabric and the polyester support layer are all non-antimony catalysts.

2. The polyester-based reverse osmosis membrane according to claim 1, characterized in that The thickness of the polyester nonwoven fabric is 60 to 120 μm; Preferably, the thickness of the polyester support layer is 25 to 60 μm; Preferably, the thickness of the polyamide functional layer is 50-200 nm.

3. The polyester-based reverse osmosis membrane according to claim 1 or 2, characterized in that: The polyester nonwoven fabric is obtained by heating the polyester resin A to melt, and then mixing, extruding, casting, stretching and heat setting; Preferably, the number average molecular weight of the polyester resin A is 20,000 to 25,000; Preferably, the polyester resin A is obtained by catalysis using a titanium catalyst A.

4. The polyester-based reverse osmosis membrane according to any one of claims 1 to 3, characterized in that: The material of the polyester support layer includes polyester resin B; Preferably, the number average molecular weight of the polyester resin B is 15000 to 25000; Preferably, the raw materials for preparing the polyester resin B include the following components in parts by weight: Preferably, the titanium catalyst A and the titanium catalyst B each independently include C-94 catalyst-titanium / silicon oxide copolymer, tetramethylphenol titanium (IV), tri(dioctyl phosphate-O") isopropanol titanium, dihydroxybis(hydrogen lactic acid) titanium (IV), bis[2-[(2-aminoethyl)amino-κN]ethanol radical-κO][2-[(2-aminoethyl)amino]ethanol radical-κO](2-propanol radical) titanium, oxo[5,10,15,20-tetra(4-pyridyl)porphine] titanium Any one or a combination of at least two of titanium dioxide, titanium bis(2,4-pentanedione)trioxide, titanium tetra(2,4-pentanedione)trioxide, titanium bis(2-hydroxypropionic acid)diammonium dihydroxide, titanium tetra(2-ethyl-1,3-hexanediol), titanium tetrachlorobis(tetrahydrofuran), (OC-6-11)hexafluorotitanate(2-)potassium, dihydroxybis(hydrogen lactate)trioxide, phthalate compounds or phthalate chelates.

5. The polyester-based reverse osmosis membrane according to any one of claims 1 to 4, characterized in that: The raw materials for preparing the polyamide functional layer include oil phase monomers and water phase monomers; Preferably, the oil phase monomers include isophthaloyl chloride and / or trimesoyl chloride; Preferably, the aqueous phase monomer comprises meta-phenylenediamine and / or iso-phenylenediamine.

6. A method for preparing a polyester-based reverse osmosis membrane as claimed in any one of claims 1 to 5, characterized in that: The preparation method comprises: sequentially forming a polyester support layer and a polyamide functional layer on one side surface of a polyester non-woven fabric to obtain the polyester-based reverse osmosis membrane.

7. The preparation method according to claim 6, characterized in that: The preparation method specifically comprises the following steps: (1) forming a polyester support layer on one surface of the polyester nonwoven fabric by a solvent phase conversion method; (2) forming a polyamide functional layer on the other side surface of the polyester support layer by interfacial polymerization to obtain the polyester-based reverse osmosis membrane.

8. The preparation method according to claim 7, characterized in that: The method for forming the polyester support layer in step (1) specifically comprises the following steps: (1A) providing a casting solution for forming the polyester support layer; (1B) coating the casting solution on one side of the polyester non-woven fabric and curing the casting solution to form the polyester support layer; Preferably, the casting solution in step (1A) is obtained by mixing polyester resin B and a solvent; Preferably, the solid content of the casting solution in step (1A) is 12-20%; Preferably, the solvent comprises any one of dimethylformamide, dimethylacetamide, dimethyl sulfoxide, sulfolane, N-methylpyrrolidone or tetrahydrofuran, or a combination of at least two thereof; Preferably, the curing in step (1B) is performed by immersing in a poor solvent to perform phase separation curing; Preferably, the poor solvent includes any one of water, ethanol or isopropanol, or a combination of at least two of them.

9. The preparation method according to claim 7 or 8, characterized in that: The method for forming the polyamide functional layer in step (2) specifically comprises the following steps: (2A) mixing an aqueous phase monomer and water to obtain an aqueous phase solution; mixing an oil phase monomer and an organic solvent to obtain an oil phase solution; (2B) contacting one side of the polyester support layer in the polyester non-woven fabric with an aqueous solution, and then contacting with an oil solution, to perform interfacial polymerization, thereby obtaining the polyester-based reverse osmosis membrane; Preferably, the mass percentage of the aqueous phase monomer in the aqueous phase solution of step (2A) is 0.8-3%; Preferably, the organic solvent in step (2A) comprises any one of n-hexane, n-decane, ethylcyclohexane or an isomeric alkane solvent, or a combination of at least two thereof; Preferably, the mass percentage of the oil phase monomer in the oil phase solution in step (2A) is 0.06-0.3%; Preferably, the temperature of the interfacial polymerization in step (2B) is 25 to 45° C. and the time is 10 to 60 seconds.

10. Use of the polyester-based reverse osmosis membrane according to any one of claims 1 to 5 in water treatment.

Images