A graphene water purification filter element material and its preparation method and application

Abstract

The present invention belongs to the field of water treatment technology, and specifically relates to a graphene water purification filter material, a preparation method thereof, and an application thereof. The preparation method of the graphene water purification filter material comprises: loading graphene oxide on a substrate material, and obtaining a graphene water purification filter material after drying, wherein the graphene oxide is used in the form of a graphene oxide dispersion; the graphene oxide is selected from at least one of chemically modified graphene oxide and / or reduced graphene oxide. The key to the present invention is to use graphene oxide and / or reduced graphene oxide chemically modified by β-cyclodextrin and / or polyethyleneimine, and the graphene water purification filter material thus prepared has high selectivity (salt ion retention rate) and deodorizing and antibacterial properties while also having high water flux, thereby achieving a good water purification effect.

Description

Technical Field

[0001] The present invention belongs to the technical field of water treatment, and in particular relates to a graphene water purification filter element material, a preparation method and an application thereof. Background Art

[0002] Water is the source of life, and obtaining safe drinking water is a basic need for human survival. According to the Drinking Water Hygiene Standard (GB5749-2006), strict hygiene requirements are stipulated for the quality of drinking water: drinking water has good sensory properties, is transparent, colorless, odorless and free of visible substances, does not contain pathogenic microorganisms and parasitic eggs, has chemical components that are harmless to the human body, and the chemicals contained in the water will not cause acute poisoning, chronic poisoning, or long-term damage to the human body. With the rapid advancement of industrialization and urbanization, the safety of drinking water in my country remains very serious. Most families drink purified water the most, but during the treatment and storage of purified water, bacteria in the air may also be introduced, causing water pollution and affecting the hygienic safety of direct drinking water.

[0003] As we all know, the most important component of a water purifier is the filter element. Household water purifiers on the market are primarily categorized into two types, ultrafiltration and reverse osmosis, based on their filter element structure. Currently, existing water purifier filters rely on filter materials ranked in ascending order of purification capacity to filter impurities from the water. PP cotton intercepts large particles, pre-activated carbon absorbs residual chlorine and other color and odor issues, high-precision PP cotton further removes impurities such as bloodworms and carbon dust, RO reverse osmosis membranes remove bacteria, heavy metals, and other harmful substances, and post-activated carbon improves taste. However, as a water purifier ages, trapped impurities accumulate in the filter element, making it prone to bacterial growth and odor.

[0004] Graphene, a new single-layer material composed of carbon atoms, possesses excellent electrical, thermal, and mechanical properties. Graphene-based nanomaterials exhibit excellent properties, including a large specific surface area, nanopore size, surface electrical properties, and functional modification. Graphene oxide (GO), one of the most important derivatives of graphene, possesses excellent film-forming properties. Graphene oxide membranes can be used as independent carbon-based membrane materials, formed by the directional assembly of individual graphene oxide sheets. Their combination of macroscopic flexibility and rigidity is the result of the unique interlocking arrangement of nanoscale graphene oxide sheets, making them possible for water purification applications and increasingly demonstrating their progress and potential. Because graphene oxide contains a variety of oxygen-containing functional groups on its surface, its application in water purification filter materials is expected to help intercept pollutants such as organic molecules and inorganic salt ions, as well as to deodorize and inhibit bacteria. However, the current graphene oxide membrane has problems of low water flux and poor stability due to the high content of hydrophilic groups on the surface. The existing technology mostly uses cross-linking method, interlayer support method, etc. to improve the water flux of graphene oxide membrane, but these methods will lead to a decrease in the selectivity of graphene oxide membrane and poor water purification effect. Summary of the Invention

[0005] One of the purposes of the present invention is to address the problem that the graphene-modified water purification filter element materials in the prior art have difficulty in achieving high water flux, good stability and selectivity at the same time, and to provide a method for preparing a graphene water purification filter element material. The graphene water purification filter element material prepared in this way has high selectivity (salt ion retention rate) and deodorizing and antibacterial properties while also having high water flux, thereby achieving good water purification effect.

[0006] Specifically, the preparation method of the graphene water purification filter element material includes loading graphene oxide on a base material and obtaining the graphene water purification filter element material after drying, wherein the graphene oxide is used in the form of a graphene oxide dispersion; the graphene oxide is selected from chemically modified graphene oxide and / or reduced graphene oxide; the chemically modified graphene oxide is obtained by chemically modifying graphene oxide using β-cyclodextrin and / or polyethyleneimine; the reduced graphene oxide is obtained by partially reducing and modifying graphene oxide by at least one of adding a reducing agent, heating reduction, and ultraviolet reduction.

[0007] In a preferred embodiment, the content of graphene oxide in the graphene water purification filter element material is 0.5-15wt%.

[0008] In a preferred embodiment, the average sheet diameter of the graphene oxide is 0.02-100 μm.

[0009] In a preferred embodiment, the concentration of graphene oxide in the dispersion is 0.01-2 wt %.

[0010] In a preferred embodiment, the preparation method of the chemically modified graphene oxide comprises: (1) reacting β-cyclodextrin with graphene oxide under alkaline conditions at 50-100° C. for 4-8 hours; or, (2) mixing polyethyleneimine with graphene oxide and reacting them under ultrasonic conditions for 4-8 hours.

[0011] In a preferred embodiment, the mass ratio of the β-cyclodextrin and / or polyethyleneimine to graphene oxide is (0.05-15):1.

[0012] In a preferred embodiment, the preparation method of reduced graphene oxide comprises: (I) reacting graphene oxide with a reducing agent at 80-100°C for 6-24 hours; or, (II) heating graphene oxide at 140-180°C for a reduction reaction for 4-8 hours; or, (III) reducing graphene oxide under ultraviolet light for 1-3 hours, wherein the ultraviolet reduction method is carried out before or after the graphene oxide is loaded on the substrate material.

[0013] In a preferred embodiment, the reduced graphene oxide is obtained by reducing and modifying graphene oxide by at least one of adding a reducing agent, heating reduction, and ultraviolet reduction.

[0014] In a preferred embodiment, the reducing agent is selected from at least one of ascorbic acid, glucose, tannic acid, and chitosan.

[0015] In a preferred embodiment, the mass ratio of the reducing agent to graphene oxide is (1-10):1.

[0016] In a preferred embodiment, the base material is selected from at least one of activated carbon, carbon fiber, PP cotton and PO film.

[0017] In a preferred embodiment, when the base material is activated carbon and / or carbon fiber, the preparation method of the graphene water purification filter element material includes: mixing the activated carbon and / or carbon fiber with the graphene oxide dispersion, performing vacuum filtration, and obtaining the graphene water purification filter element material after drying.

[0018] In a preferred embodiment, when the base material is PP cotton and / or PO membrane, the preparation method of the graphene water purification filter element material includes: loading the graphene oxide dispersion on the PP cotton and / or PO membrane by at least one of immersion, spin coating, spraying and roller coating, and then vacuum filtering and drying to obtain the graphene water purification filter element material.

[0019] A second object of the present invention is to provide a graphene water purification filter element material prepared by the above method.

[0020] The third object of the present invention is to provide the application of the above-mentioned graphene water purification filter material in water purification treatment.

[0021] The key to the present invention is to use graphene oxide and / or reduced graphene oxide chemically modified by β-cyclodextrin and / or polyethyleneimine. On this basis, the graphene oxide is loaded on a substrate material to obtain a graphene water purification filter element material. Compared with the existing technology, the graphene water purification filter element material has the following beneficial effects:

[0022] (1) Since the surface of graphene oxide has epoxy, hydroxyl, carboxyl, carbonyl and other oxygen-containing groups, these groups make the surface of the graphene water purification filter material electronegative, which can play a role in deodorization and antibacterial, and can also intercept salt ions in water;

[0023] (2) Using chemically modified and / or partially reduced graphene oxide, on the one hand, chemical modification can expand the interlayer spacing of graphene oxide and improve water flux, and the organic combination of chemical modification additives and graphene oxide can also produce a synergistic adsorption effect, thereby improving the salt ion retention rate; on the other hand, the graphene oxide is partially reduced and modified by at least one method of adding a reducing agent, heating reduction, and ultraviolet reduction, so that the reduced-modified graphene oxide increases the number of water transmission channels while maintaining sufficient hydrophilic properties and interlayer spacing, and at the same time improves the selective separation and retention rate of the graphene water purification filter material for salt ions and the water molecule transmission rate (water flux);

[0024] (3) Graphene oxide is loaded on the substrate material by vacuum filtration. Compared with other processes, the preparation process is simple, the energy consumption is low at room temperature, and the raw materials are cheap and safe.

[0025] In a preferred embodiment, by regulating the sheet diameter of graphene oxide and the concentration of graphene oxide dispersion, on the one hand, the graphene water purification filter material has better film-forming performance, can form a complete membrane structure, reduce structural defects, and improve the salt ion retention rate; on the other hand, it helps to construct a shorter water molecule transmission path and improve water flux. DETAILED DESCRIPTION

[0026] The preparation method of the graphene water purification filter element material provided by the present invention comprises: loading graphene oxide on a substrate material, and obtaining the graphene water purification filter element material after drying, wherein the graphene oxide is used in the form of a graphene oxide dispersion. The graphene oxide is selected from at least one of unmodified graphene oxide, chemically modified graphene oxide, and reduced graphene oxide. In the present invention, the graphene oxide is loaded onto the substrate material in the form of a dispersion. This method can better uniformly load the graphene oxide on the substrate material, which is conducive to the interlocking of the graphene oxides to form a good membrane structure.

[0027] In the present invention, the graphene oxide content in the graphene water purification filter element material is preferably 0.5-15wt%, such as 0.5wt%, 0.8wt%, 1wt%, 2wt%, 5wt%, 8wt%, 10wt%, 12wt%, 15wt%, or any value therebetween. When the graphene oxide content is controlled within this preferred range, the resulting graphene water purification filter element material has better film-forming properties, fewer defective structures, and is more conducive to improving salt ion retention.

[0028] In the present invention, the average sheet diameter of the graphene oxide is preferably 0.02-100 μm, such as 0.02 μm, 0.05 μm, 0.08 μm, 0.1 μm, 0.2 μm, 0.5 μm, 0.8 μm, 1 μm, 2 μm, 5 μm, 8 μm, 10 μm, 50 μm, 100 μm or any value therebetween. The concentration of the graphene oxide in the dispersion is preferably 0.01-2 wt%, such as 0.01 wt%, 0.02 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.5 wt%, 2 wt% or any value therebetween. Controlling the concentration of graphene oxide in the dispersion within the above-mentioned preferred range is more conducive to improving the dispersion performance of graphene oxide. At the same time, controlling the average flake diameter of graphene oxide within the above-mentioned preferred range is more conducive to improving the film forming property and the integrity of the membrane structure during vacuum filtration, and is more conducive to constructing a water transport channel with a shorter path, thereby improving water flux.

[0029] In the present invention, the chemically modified graphene oxide is obtained by chemically modifying graphene oxide using β-cyclodextrin and / or polyethyleneimine. The mass ratio of the β-cyclodextrin and / or polyethyleneimine to graphene oxide is preferably (0.05-15):1, such as 0.05:1, 0.1:1, 0.3:1, 0.6:1, 1:1, 2:1, 5:1, 10:1, 15:1, or any value therebetween. Within this preferred range, the structure-activity relationship of regulating the interaction between the graphene oxide nanolayers and controlling the transport channel is facilitated, and the organic combination of β-cyclodextrin, polyethyleneimine, and graphene oxide also exhibits a synergistic adsorption effect.

[0030] In the present invention, the preparation method of the chemically modified graphene oxide preferably comprises: (1) reacting β-cyclodextrin with graphene oxide under alkaline conditions at 50-100°C for 4-8 hours; or, (2) mixing polyethyleneimine with graphene oxide and reacting them under ultrasonic conditions for 4-8 hours. In the preparation method (1), the alkaline conditions can be obtained by adding at least one of sodium hydroxide, potassium hydroxide, and ammonia water; the reaction temperature is preferably 50-100°C, such as 50°C, 60°C, 70°C, 80°C, 90°C, 100°C or any value therebetween; the reaction time is preferably 4-8 hours, such as 4h, 5h, 6h, 7h, 8h or any value therebetween. In the preparation method (2), the reaction can be carried out at room temperature; the reaction time is preferably 4-8 hours, such as 4h, 5h, 6h, 7h, 8h or any value therebetween.

[0031] In a specific embodiment, the preparation method of β-cyclodextrin-modified graphene oxide may include the following steps: preparing an alkaline solution, adding β-cyclodextrin, first reacting at 50-100°C for 0.5-1h, then adding a graphene oxide dispersion, reacting at 50-100°C for 4-8h, and separating the product, which is β-cyclodextrin-modified graphene oxide.

[0032] In the present invention, the reduced graphene oxide is obtained by partially reducing and modifying the graphene oxide by at least one of adding a reducing agent, heating reduction, and ultraviolet reduction.

[0033] In the present invention, the method for preparing reduced graphene oxide preferably comprises: (I) reacting graphene oxide with a reducing agent at 80-100°C for 6-24 hours; or, (II) heating the graphene oxide at 140-180°C for a reduction reaction for 4-8 hours; or, (III) reducing the graphene oxide under ultraviolet light for 1-3 hours, wherein the ultraviolet reduction method can be performed before or after the graphene oxide is loaded on the substrate material. In preparation method (I), the reaction temperature is preferably 80-100°C, such as 80°C, 85°C, 90°C, 95°C, 100°C, or any value therebetween; and the reaction time is preferably 6-24 hours, such as 6 hours, 8 hours, 10 hours, 12 hours, 15 hours, 20 hours, 24 hours, or any value therebetween. In preparation method (II), the reaction temperature is preferably 140-180°C, such as 140°C, 150°C, 160°C, 170°C, 180°C, or any value therebetween; the reaction time is preferably 4-8 hours, such as 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, or any value therebetween. In preparation method (III), the reduction time is preferably 1-3 hours, such as 1 hour, 1.5 hours, 2 hours, 2.5 hours, 3 hours, or any value therebetween.

[0034] In the present invention, the reducing agent is preferably at least one selected from ascorbic acid, glucose, tannic acid, and chitosan, more preferably ascorbic acid and / or glucose.

[0035] In the present invention, the mass ratio of the reducing agent to the graphene oxide is preferably (1-10):1, such as 1:1, 2:1, 4:1, 5:1, 6:1, 8:1, 10:1 or any value therebetween. Within this preferred range, it is more advantageous to perform weak reduction modification on the graphene oxide, so that the graphene oxide can maintain sufficient hydrophilic properties and interlayer spacing, while increasing the number of water transmission channels, and being more advantageous in improving the selective separation and retention rate of the graphene water purification filter material for salt ions and the water molecule transmission rate (water flux).

[0036] In the present invention, the specific type of the base material is not limited, as long as it is a filter element material commonly used in the prior art. Preferably, the base material can be at least one of activated carbon, carbon fiber, PP cotton and PO membrane.

[0037] In the present invention, when the base material is activated carbon and / or carbon fiber, the preparation method of the graphene water purification filter element material preferably includes: mixing the activated carbon and / or carbon fiber with a graphene oxide dispersion, vacuum filtration, and drying to obtain the graphene water purification filter element material. Specifically, the preparation method can be: after the activated carbon and / or carbon fiber and the graphene oxide dispersion are uniformly mixed by ultrasound, stirring or any other known mixing method, the graphene oxide is deposited on the activated carbon and / or carbon fiber base material by vacuum filtration, and the graphene water purification filter element material is obtained after drying. The drying method can be natural air drying or drying in an oven.

[0038] In the present invention, when the base material is PP cotton and / or PO membrane, the preparation method of the graphene water purification filter element material preferably includes: loading the graphene oxide dispersion on the PP cotton and / or PO membrane by at least one of immersion, spin coating, spraying and roller coating, and then vacuum filtering and drying to obtain the graphene water purification filter element material.

[0039] The present invention will be described in detail below through specific examples.

[0040] Example 1

[0041] 1) 250 mL of a graphene oxide dispersion (concentration of 0.1 wt %, average flake diameter of 100 nm) was added with 1.5 g of ascorbic acid, and the mixture was stirred at 90° C. for 6 h. After multiple washing and drying, a reduced graphene oxide dispersion (concentration of 0.1 wt %, average flake diameter of 100 nm) was obtained.

[0042] 2) uniformly mixing 3 g of carbon fiber, 0.25 g of activated carbon, and 250 mL of the reduced graphene oxide dispersion prepared in step 1);

[0043] 3) The reduced graphene oxide was deposited on the carbon fiber and activated carbon substrate materials by vacuum filtration, and the materials were placed in an oven and dried at 60° C. for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 7.14 wt%).

[0044] Example 2

[0045] 1) 3 g of carbon fiber, 0.25 g of activated carbon, and 250 mL of graphene oxide dispersion (concentration of 0.1 wt %, average flake diameter of 2 μm) were uniformly mixed;

[0046] 2) Graphene oxide sheets were deposited on carbon fiber and activated carbon substrates by vacuum filtration, dried in an oven at 60°C for 2 h, and then irradiated with ultraviolet light (λ = 254 nm) for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 7.14 wt%).

[0047] Example 3

[0048] 1) 250 mL of a graphene oxide dispersion (concentration of 0.1 wt %, average flake diameter of 2 μm) was added with 1.5 g of ascorbic acid, and the mixture was stirred at 90° C. for 6 h. After multiple washing and drying, a reduced graphene oxide dispersion (concentration of 0.1 wt %, average flake diameter of 2 μm) was obtained.

[0049] 2) uniformly mixing 3 g of carbon fiber, 0.25 g of activated carbon, and 250 mL of the reduced graphene oxide dispersion prepared in step 1);

[0050] 3) The reduced graphene oxide was deposited on the carbon fiber and activated carbon substrate materials by vacuum filtration, and the materials were placed in an oven and dried at 60° C. for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 7.14 wt%).

[0051] Example 4

[0052] 1) Weigh 1.5 g of sodium hydroxide and dissolve it in water. Add 0.15 g of β-cyclodextrin (β-CD) to the solution. After it is fully dissolved, gelate at 80° C. for 0.5 h. Then, add 250 mL of graphene oxide dispersion (concentration of 0.1 wt %, flake size of 50 μm) to the β-CD solution. Continue stirring and react at 80° C. for 3 h. Then, reduce the temperature to 50° C. and react for 1.5 h. The product is centrifuged and washed multiple times at 3500 rpm to obtain β-cyclodextrin-modified graphene oxide (β-CD / GO). β-CD / GO dispersion (concentration of 0.1 wt %, average flake size of 50 μm) is prepared.

[0053] 2) 3 g of carbon fiber, 0.25 g of activated carbon, and 250 mL of the β-CD / GO dispersion prepared in step 1) were uniformly mixed;

[0054] 3) β-CD / GO was deposited on the carbon fiber and activated carbon substrate materials by vacuum filtration, and then placed in an oven at 60° C. for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 7.14 wt%).

[0055] Example 5

[0056] 1) Weigh 1.5 g of sodium hydroxide and dissolve it in water. Add 0.15 g of β-cyclodextrin (β-CD) to the solution. After it is fully dissolved, gelate at 80° C. for 0.5 h. Then, add 250 mL of graphene oxide dispersion (concentration: 1 wt %, flake size: 2 μm) to the β-CD solution. Continue stirring and react at 80° C. for 3 h. Then, reduce the temperature to 50° C. and react for 1.5 h. The product is centrifuged and washed multiple times at 3500 rpm to obtain β-cyclodextrin-modified graphene oxide (β-CD / GO). β-CD / GO dispersion (concentration: 1 wt %, average flake size: 2 μm) is prepared.

[0057] 2) 22 g of carbon fiber, 0.5 g of activated carbon, and 250 mL of the β-CD / GO dispersion prepared in step 1) were uniformly mixed;

[0058] 3) β-CD / GO was deposited on the carbon fiber and activated carbon substrate materials by vacuum filtration, and then placed in an oven and dried at 60° C. for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 10.00 wt%).

[0059] Example 6

[0060] 1) Add 1.25 g of polyethyleneimide (PEI) to 250 mL of graphene oxide dispersion (concentration of 0.5 wt %, average flake diameter of 50 μm) and sonicate for 1 h to obtain a uniform PEI / GO mixed dispersion solution;

[0061] 2) 14 g of carbon fiber, 0.25 g of activated carbon, and 250 mL of the PEI / GO dispersion prepared in step 1) were uniformly mixed, and the PEI / GO was deposited on the carbon fiber and activated carbon substrates by vacuum filtration. The mixture was then dried in an oven at 60° C. for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 8.06 wt%).

[0062] Example 7

[0063] 1) placing 250 mL of a graphene oxide dispersion (0.1 wt % concentration, 20 nm average flake diameter) into an autoclave for thermal reduction treatment at 160° C. for 6 h, followed by preparation of a reduced graphene oxide dispersion;

[0064] 2) 250 mL of the reduced graphene oxide dispersion prepared in step 1) was evenly sprayed onto 5 g of a PP cotton substrate using a sprayer. The mixture was then vacuum filtered to accelerate water removal and reduced graphene oxide loading. The mixture was then dried in an oven at 60° C. for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 4.76 wt%).

[0065] Example 8

[0066] 1) 250 mL of a graphene oxide dispersion (0.1 wt % and an average flake diameter of 50 μm) was added with 1.5 g of ascorbic acid, and the mixture was stirred at 90° C. for 6 h. After multiple washing and drying, a reduced graphene oxide dispersion (0.1 wt % and an average flake diameter of 50 μm) was obtained.

[0067] 2) 250 mL of the reduced graphene oxide dispersion prepared in step 1) was evenly sprayed onto 5 g of a PP cotton substrate using a sprayer. The mixture was then vacuum filtered to accelerate water removal and reduced graphene oxide loading. The mixture was then dried in an oven at 60° C. for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 4.76 wt%).

[0068] Example 9

[0069] 1) Add 1.25 g of polyethyleneimide (PEI) to 250 mL of graphene oxide dispersion (concentration: 2 wt %, average flake diameter: 50 μm) and sonicate for 1 h to obtain a uniform PEI / GO mixed dispersion solution;

[0070] 2) 250 mL of the PEI / GO dispersion prepared in step 1) was evenly sprayed onto 30 g of a PP cotton substrate using a sprayer. Vacuum filtration was then performed to accelerate water removal and PEI / GO loading. The dispersion was then dried in an oven at 60° C. for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 14.30 wt %).

[0071] Example 10

[0072] 1) 250 mL of a graphene oxide dispersion (concentration of 0.1 wt %, average flake diameter of 100 μm) was added with 1.5 g of ascorbic acid, and the mixture was stirred at 90° C. for 24 h. After multiple washing and drying, a reduced graphene oxide dispersion (concentration of 0.1 wt %, average flake diameter of 100 μm) was obtained.

[0073] 2) adjusting the temperature of the PP cotton substrate to 70° C. and the rotation speed to 800 rpm, and then dropping 250 mL of the reduced graphene oxide aqueous dispersion prepared in step 1) onto 5 g of the PP cotton material, so that the dispersion is evenly spread on the surface of the substrate to form a uniform, flat and dense structure;

[0074] 3) accelerating water removal and graphene oxide loading by vacuum filtration, and baking in an oven at 60° C. for 2 h to obtain a graphene water purification filter element material (graphene oxide content is approximately 4.76 wt %).

[0075] Example 11

[0076] 1) Add 0.25 g of polyethyleneimide (PEI) to 250 mL of graphene oxide dispersion (concentration of 0.01 wt%, average flake diameter of 50 μm) and sonicate for 1 h to obtain a uniform PEI / GO mixed dispersion solution;

[0077] 2) adjusting the temperature of the PP cotton substrate to 70° C. and the rotation speed to 800 rpm, and then dropping 250 mL of the reduced graphene oxide aqueous dispersion prepared in step 1) onto 5 g of the PP cotton material, so that the dispersion is evenly spread on the surface of the substrate to form a uniform, flat and dense structure;

[0078] 3) accelerating water removal and graphene oxide loading by vacuum filtration, and baking in an oven at 60° C. for 2 h to obtain a graphene water purification filter element material (graphene oxide content is about 0.50 wt %).

[0079] Example 12

[0080] 1) Add 1.25 g of polyethyleneimide (PEI) to 250 mL of graphene oxide dispersion (concentration of 0.5 wt %, average flake diameter of 50 μm) and sonicate for 1 h to obtain a uniform PEI / GO mixed dispersion solution;

[0081] 2) 14 g of carbon fiber, 0.25 g of activated carbon, and 250 mL of the PEI / GO dispersion prepared in step 1) were uniformly mixed, and PEI / GO was deposited on the carbon fiber and activated carbon substrates by vacuum filtration. The mixture was then dried in an oven at 60° C. for 2 h, and then irradiated with ultraviolet light (λ=254 nm) for reduction for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 8.06 wt%).

[0082] Example 13

[0083] 1) taking 250 mL of graphene oxide dispersion (concentration of 0.2 wt %, average flake diameter of 2 μm), adding 0.5 g of glucose, stirring and reacting at 90° C. for 6 h, washing and drying multiple times to obtain a reduced graphene oxide dispersion (concentration of 0.2 wt %, average flake diameter of 2 μm);

[0084] 2) uniformly mixing 5 g of carbon fiber, 0.25 g of activated carbon, and 250 mL of the reduced graphene oxide dispersion prepared in step 1);

[0085] 3) The reduced graphene oxide was deposited on the carbon fiber and activated carbon substrate materials by vacuum filtration, and the materials were placed in an oven and dried at 60° C. for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 8.70 wt%).

[0086] Example 14

[0087] 1) Add 1.25 g of polyethyleneimide (PEI) to 250 mL of graphene oxide dispersion (5 wt % and 250 μm average flake diameter) and sonicate for 1 h to obtain a uniform PEI / GO mixed dispersion.

[0088] 2) 32 g of carbon fiber, 0.5 g of activated carbon, and 250 mL of the PEI / GO dispersion prepared in step 1) were uniformly mixed, and PEI / GO was deposited on the carbon fiber and activated carbon substrates by vacuum filtration. The mixture was then dried in an oven at 60° C. for 2 h, and then irradiated with ultraviolet light (λ=254 nm) for reduction for 2 h to obtain a graphene water purification filter element material (with a graphene oxide content of approximately 27.80 wt%).

[0089] Comparative Example 1

[0090] 1) 3 g of carbon fiber, 0.25 g of activated carbon, and 250 mL of graphene oxide dispersion (concentration of 0.1 wt %, average flake diameter of 50 μm) were uniformly mixed;

[0091] 2) Graphene oxide was deposited on the carbon fiber and activated carbon substrate materials by vacuum filtration, and the materials were placed in an oven and dried at 60° C. for 2 h to obtain a reference graphene water purification filter element material.

[0092] Comparative Example 2

[0093] A reference water purification filter element material was prepared according to the method of Comparative Example 1, except that no graphene oxide dispersion was added, and the other conditions were the same.

[0094] Comparative Example 3

[0095] Unmodified PP cotton.

[0096] Test Case

[0097] The graphene water purification filter materials prepared in the above examples and comparative examples were assembled into membrane modules and tested for deodorization effect, water flux, and salt ion retention efficiency according to the following methods. The results are shown in Table 1.

[0098] (1) Deodorization effect: After a liquid with a distinct odor is treated with the above-mentioned graphene water purification filter material, a deodorization effect sensory test is conducted.

[0099] (2) Water flux test and salt ion retention efficiency test: a certain volume of salt ion solution (Cu 2+ , Pb 2+ Cr 2 + 、Cd 2+ ) into the filter cup, immerse the membrane assembly in the solution, turn on the vacuum pump and start collecting the filtrate after the water output stabilizes. Use a centrifuge tube to collect 2 to 5 mL of filtrate each time and record the corresponding mass change and time used.

[0100] The water flux was calculated using the following formula: J0 = V / AtP, where J0 is the pure water flux (PWF), V is the collected volume of water (due to the relatively low concentration of the solution in the experiment, the volume change is approximately equal to the weighed mass), A is the effective surface area of ​​the membrane, t is the time, and P is the operating pressure.

[0101] The retention rate of salt ions is calculated by the following formula: f -C p ) / C f ×100%, C p is the concentration of salt ions in the filtrate, C f To determine the concentration of salt ions in water before filtration (specific value 40-46 mg / L), the concentration of metal salt ions was measured using an atomic absorption spectrometer.

[0102] Table 1

[0103]

[0104]

[0105] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention.

Claims

1. A method for preparing a graphene water purification filter element material, characterized in that: The preparation method comprises: loading graphene oxide on a base material, and obtaining a graphene water purification filter element material after drying, wherein the graphene oxide is used in the form of a graphene oxide dispersion; the graphene oxide is selected from chemically modified graphene oxide; the chemically modified graphene oxide is obtained by chemically modifying graphene oxide using β-cyclodextrin; the content of graphene oxide in the graphene water purification filter element material is 0.5-15wt%; the average sheet diameter of the graphene oxide is 0.02-100μm; and the mass ratio of the β-cyclodextrin to the graphene oxide is (0.05-15):

1.

2. The method for preparing the graphene water purification filter element material according to claim 1, wherein: The concentration of graphene oxide in the dispersion is 0.01-2 wt %.

3. The method for preparing the graphene water purification filter element material according to claim 1, wherein: The preparation method of the chemically modified graphene oxide comprises: (1) reacting β-cyclodextrin and graphene oxide under alkaline conditions at 50-100° C. for 4-8 hours.

4. The method for preparing the graphene water purification filter element material according to claim 1, wherein: The base material is selected from at least one of activated carbon, carbon fiber, PP cotton and PO film.

5. The method for preparing the graphene water purification filter element material according to claim 4, wherein: When the base material is activated carbon and / or carbon fiber, the preparation method of the graphene water purification filter element material includes: mixing the activated carbon and / or carbon fiber with a graphene oxide dispersion, performing vacuum filtration, and obtaining the graphene water purification filter element material after drying.

6. The method for preparing the graphene water purification filter element material according to claim 4, characterized in that: When the base material is PP cotton and / or PO membrane, the preparation method of the graphene water purification filter element material includes: loading the graphene oxide dispersion on the PP cotton and / or PO membrane by at least one of immersion, spin coating, spraying and roller coating, and then vacuum filtering and drying to obtain the graphene water purification filter element material.

7. A graphene water purification filter element material prepared by the method for preparing a graphene water purification filter element material according to any one of claims 1 to 6.

8. Use of the graphene water purification filter element material according to claim 7 in water purification treatment.

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