CN112316726A - Graphene ultrafiltration membrane and preparation method thereof - Google Patents
Graphene ultrafiltration membrane and preparation method thereof Download PDFInfo
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- CN112316726A CN112316726A CN202011139563.0A CN202011139563A CN112316726A CN 112316726 A CN112316726 A CN 112316726A CN 202011139563 A CN202011139563 A CN 202011139563A CN 112316726 A CN112316726 A CN 112316726A
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- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/14—Ultrafiltration; Microfiltration
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Abstract
The invention discloses a graphene ultrafiltration membrane and a preparation method thereof, relates to the field of waste liquid recovery, and comprises the following steps: pouring concentrated sulfuric acid and sodium nitrate into a beaker for mixing; step two: placing the beaker in a constant-temperature water bath and uniformly stirring; step three: adding deionized water and hydrogen peroxide into the mixed solution, carrying out centrifugal washing, and drying to obtain graphite oxide powder; step four: pouring graphite powder into an ethanol solution, adding cobalt nitrate hexahydrate, uniformly stirring, and drying to obtain graphene oxide; step five: and diluting the graphene oxide with water, and performing ultrasonic treatment to obtain a graphene oxide aqueous solution. According to the invention, polyethylene glycol is added into the graphene aqueous solution and uniformly mixed, so that pores in the prepared graphene ultrafiltration membrane are increased, and the nano high-tension particles are ground and added with water to prepare a nano solution which is added into the membrane casting solution, so that the tension and strength of the prepared graphene ultrafiltration membrane are increased.
Description
Technical Field
The invention relates to the technical field of graphene ultrafiltration membranes, in particular to a graphene ultrafiltration membrane and a preparation method thereof.
Background
The graphene is sp2The hybridized and connected carbon atoms are tightly stacked to form a new material with a single-layer two-dimensional honeycomb lattice structure, and the graphene has excellent optical, electrical and mechanical properties and can be used in materials science, micro-nano processing, energy, biomedicine and the likeThe graphene oxide has an important application prospect in the aspects of drug delivery and the like, is considered as a future revolutionary material, has a layered structure which is extremely similar to that of graphene, meanwhile, the surface of the graphene oxide is rich in a large number of active groups such as hydroxyl, epoxy, carboxyl and the like, the large ion exchange capacity of the graphene oxide is determined by the ultra-large specific surface area and the layered structure of the graphene oxide, the uniform dispersion of the graphene oxide in water is determined by the oxygen-containing groups rich on the surface of the layered structure, hydrophilic molecules, polymers and the like can be inserted between graphene oxide layers through the actions of interlayer hydrogen bonds, ionic bonds, covalent bonds and the like to form interlayer compounds, so that the interlayer compounds have great potential and application prospect in the field of separation materials, and the ultrafiltration membrane is widely applied to the water treatment industry as a common method in the deep treatment of water, however, the membrane technology has been restricted by membrane contamination caused by the decrease in pore size or clogging due to adsorption and deposition on the membrane surface.
However, the graphene ultrafiltration membrane prepared from the existing graphene has low porosity, so that the water permeability is low, the filtering effect of the graphene ultrafiltration membrane is poor, the filtering time is long, and the graphene ultrafiltration membrane has low strength, so that the graphene ultrafiltration membrane has small pulling force and is easy to break, and certain specific requirements cannot be met.
Disclosure of Invention
The invention aims to: in order to solve the problems that the graphene ultrafiltration membrane is low in porosity and small in tensile force and easy to break, the graphene ultrafiltration membrane and the preparation method thereof are provided.
In order to achieve the purpose, the invention provides the following technical scheme: a graphene ultrafiltration membrane and a preparation method thereof comprise the following steps:
the method comprises the following steps: pouring concentrated sulfuric acid and sodium nitrate into a beaker for mixing;
step two: placing the beaker in a constant-temperature water bath and uniformly stirring;
step three: adding deionized water and hydrogen peroxide into the mixed solution, carrying out centrifugal washing, and drying to obtain graphite oxide powder;
step four: pouring graphite powder into an ethanol solution, adding cobalt nitrate hexahydrate, uniformly stirring, and drying to obtain graphene oxide;
step five: diluting graphene oxide with water, and performing ultrasonic treatment to obtain a graphene oxide aqueous solution;
step six: adding polyethylene glycol into the graphene oxide aqueous solution, and uniformly mixing;
step seven: adding sodium hydroxide and chloroacetic acid into the mixed solution, carrying out ultrasonic treatment, washing, and drying to obtain carboxylated graphene oxide;
step eight: dispersing the carboxylated graphene oxide in a double solvent consisting of dimethylacetamide and triethyl phosphate, then adding polyvinylidene fluoride, and mechanically stirring and dissolving to obtain a casting solution;
step nine: and (3) crushing the nano high-tension master batch, adding water to prepare a nano solution, pouring the nano solution into the graphene oxide aqueous solution, and uniformly mixing.
Preferably, in the step one, the beaker filled with the mixed solution of concentrated sulfuric acid and sodium nitrate is placed in an ice bath box for cooling treatment, and after cooling, the crystalline flake graphite is added and uniformly stirred.
Preferably, deionized water is added in the third step to terminate the reaction, meanwhile, hydrogen peroxide is added, the product is centrifugally washed by dilute salt, and then dried in a vacuum oven to obtain graphite oxide powder.
Preferably, the mixed solution obtained in the fourth step is added with cobalt nitrate hexahydrate, stirred until the mixture is uniformly mixed, refluxed and heated, washed with ethanol, and finally dried in a vacuum oven to obtain the graphene oxide.
Preferably, the polyethylene glycol in the sixth step can increase the pore-forming rate of the membrane and the water permeability of the ultrafiltration membrane.
Preferably, in the seventh step, sodium hydroxide and chloroacetic acid are added into the aqueous solution of graphene oxide, the ultrasonic treatment is continued for three hours, the obtained mixed solution is repeatedly washed by deionized water until the ph of the effluent is 7.0, the obtained mixed solution is filtered, the obtained filter cake is dried at 50 ℃, and the carboxylated graphene oxide is obtained after drying.
Preferably, in the ninth step, the nano high-tension master batch is firstly made into nano high-tension powder by a pulverizer, and then the nano high-tension powder is added with water to prepare a nano high-tension solution.
Preferably, the casting solution obtained in the step ten is naturally cooled to room temperature, and a film is scraped on a glass plate; and then immersing the glass plate with the scraping film into a gel water bath at 20-30 ℃ for phase separation to form a film, soaking the film for 3-5 days by using deionized water, taking out the film, and naturally airing the film in the air to obtain the graphene ultrafiltration film.
Compared with the prior art, the invention has the beneficial effects that: according to the invention, the polyethylene glycol solution is added into the graphene aqueous solution and is fully and uniformly mixed, so that pores in the prepared graphene ultrafiltration membrane can be increased by the polyethylene glycol, and the nano high-tension particles are ground and added with water to prepare the nano solution which is added into the membrane casting solution, so that the tension and strength of the prepared graphene ultrafiltration membrane are increased.
Drawings
FIG. 1 is a schematic flow chart of the method of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Referring to fig. 1, a graphene ultrafiltration membrane and a method for preparing the same includes the following steps:
the method comprises the following steps: pouring concentrated sulfuric acid and sodium nitrate into a beaker for mixing;
step two: placing the beaker in a constant-temperature water bath and uniformly stirring;
step three: adding deionized water and hydrogen peroxide into the mixed solution, carrying out centrifugal washing, and drying to obtain graphite oxide powder;
step four: pouring graphite powder into an ethanol solution, adding cobalt nitrate hexahydrate, uniformly stirring, and drying to obtain graphene oxide;
step five: diluting graphene oxide with water, and performing ultrasonic treatment to obtain a graphene oxide aqueous solution;
step six: adding polyethylene glycol into the graphene oxide aqueous solution, and uniformly mixing;
step seven: adding sodium hydroxide and chloroacetic acid into the mixed solution, carrying out ultrasonic treatment, washing, and drying to obtain carboxylated graphene oxide;
step eight: dispersing the carboxylated graphene oxide in a double solvent consisting of dimethylacetamide and triethyl phosphate, then adding polyvinylidene fluoride, and mechanically stirring and dissolving to obtain a casting solution;
step nine: and (3) crushing the nano high-tension master batch, adding water to prepare a nano solution, pouring the nano solution into the graphene oxide aqueous solution, and uniformly mixing.
Example 1
As a preferred embodiment of the present invention: putting a beaker filled with mixed solution of concentrated sulfuric acid and sodium nitrate into an ice bath box for cooling treatment, adding crystalline flake graphite after cooling, and uniformly stirring;
concentrated sulfuric acid is a sulfuric acid aqueous solution with the mass fraction of more than or equal to 70 percent, commonly known as bad water, has strong corrosivity, dehydration property, difficult volatility, acidity, water absorbability and the like, sodium nitrate, also known as chilisant, is an inorganic substance, has a chemical formula of NaNO3, has a molecular weight of 84.99, is a hygroscopic colorless transparent trigonal crystal, is very easy to dissolve in water, is crystalline flake graphite which is natural aphanitic graphite and is shaped like fish phosphorus, belongs to a hexagonal system, has a layered structure, has good performances of high temperature resistance, electric conduction, heat conduction, lubrication, plasticity, acid and alkali resistance and the like, is uniformly stirred with a mixed solution of the concentrated sulfuric acid and the sodium nitrate for one to two hours after being ground, and can increase the electric conductivity of liquid.
Example 2
As a preferred embodiment of the present invention: adding deionized water to terminate the reaction, simultaneously adding hydrogen peroxide, centrifugally washing the product by using dilute salt, and drying in a vacuum oven to obtain graphite oxide powder;
deionized water refers to a prepared stock solution of pure water from which impurities in the form of ions are removed, the solution is reacted with hydrogen peroxide to terminate, then the solution is put into a centrifuge, diluted saline water is poured into the centrifuge, the product is centrifugally washed by the diluted saline water, and after washing, the product is put into a vacuum drying oven to be dried, so that graphite oxide powder is obtained.
Example 3
As a preferred embodiment of the present invention: adding cobalt nitrate hexahydrate into the mixed solution in the fourth step, stirring until the cobalt nitrate hexahydrate is uniformly mixed, refluxing and heating the mixture, washing the mixture by using ethanol, and finally drying the mixture in a vacuum oven to prepare graphene oxide;
adding graphite oxide powder into an ethanol solution, uniformly mixing, adding cobalt nitrate hexahydrate into the mixed solution, stirring until uniform mixing, refluxing and heating the mixture, washing with ethanol, and finally drying in a vacuum oven to obtain the graphene oxide.
Example 4
As a preferred embodiment of the present invention: in the sixth step, the polyethylene glycol can increase the pore-forming rate of the membrane and the water permeability of the ultrafiltration membrane;
polyethylene glycol is a compound of the formula HO (CH)2 CH2O) nH, its series products have no irritation, slightly bitter taste, good water solubility, and good compatibility with many organic components, they have excellent lubricity, moisture retention, dispersibility, adhesive, antistatic agent and softening agent, etc., polyethylene glycol is a better pore-forming agent.
Example 5
As a preferred embodiment of the present invention: adding sodium hydroxide and chloroacetic acid into the aqueous solution of the graphene oxide, continuing to perform ultrasonic treatment for three hours, repeatedly washing the obtained mixed solution with deionized water until the pH of the effluent is 7.0, filtering, drying the obtained filter cake at 50 ℃, and drying to obtain the carboxylated graphene oxide;
sodium hydroxide, an inorganic compound, a chemical formula of NaOH, also called caustic soda, solid caustic soda, caustic soda and caustic soda, wherein the sodium hydroxide has strong basicity and strong corrosivity and can be used as an acid neutralizer, the sodium hydroxide has strong basicity and strong hygroscopicity, is easy to dissolve in water, releases heat when dissolved, the aqueous solution is alkaline and has a greasy feeling, 1.2 g of sodium hydroxide and 1.0 g of chloroacetic acid are added, ultrasonic treatment is carried out for three hours, the obtained mixed solution is repeatedly washed by deionized water until the pH of the effluent liquid is 7.0, filtering is carried out, the obtained filter cake is dried at 50 ℃, and the carboxylated graphene oxide is obtained after drying.
Example 6
As a preferred embodiment of the present invention: in the ninth step, the nano high-tension master batch is firstly prepared into nano high-tension powder through a pulverizer, and then the nano high-tension powder is added with water to prepare nano high-tension solution;
the nano high-tension solution can enhance the strength and tension of the graphene ultrafiltration membrane, the pulverizer is a machine for pulverizing large-size solid raw materials to required sizes, the pulverizer consists of coarse crushing devices, fine crushing devices, wind power conveying devices and the like, the purpose of the pulverizer is achieved in a high-speed impact mode, and wind energy is utilized for pulverizing the materials at one time.
Example 7
As a preferred embodiment of the present invention: naturally cooling the obtained casting film liquid to room temperature, and scraping the film on a glass plate; then immersing the glass plate with the scraping film into a gel water bath at 20-30 ℃ for phase separation to form a film, then soaking the film for 3-5 days by using deionized water, taking out the film, and naturally airing the film in the air to obtain the graphene ultrafiltration film;
and (3) placing the membrane casting solution in a vessel, cooling to room temperature, pouring the liquid onto a flat glass plate after cooling, scraping redundant liquid, standing for forming a membrane, then placing the glass plate with the membrane into a water bath of a condensate gel, soaking for demoulding, soaking with deionized water, taking out, and air-drying to obtain the graphene ultrafiltration membrane.
It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.
Claims (8)
1. A graphene ultrafiltration membrane and a preparation method thereof are characterized in that: comprises the following steps:
the method comprises the following steps: pouring concentrated sulfuric acid and sodium nitrate into a beaker for mixing;
step two: placing the beaker in a constant-temperature water bath and uniformly stirring;
step three: adding deionized water and hydrogen peroxide into the mixed solution, carrying out centrifugal washing, and drying to obtain graphite oxide powder;
step four: pouring graphite powder into an ethanol solution, adding cobalt nitrate hexahydrate, uniformly stirring, and drying to obtain graphene oxide;
step five: diluting graphene oxide with water, and performing ultrasonic treatment to obtain a graphene oxide aqueous solution;
step six: adding polyethylene glycol into the graphene oxide aqueous solution, and uniformly mixing;
step seven: adding sodium hydroxide and chloroacetic acid into the mixed solution, carrying out ultrasonic treatment, washing, and drying to obtain carboxylated graphene oxide;
step eight: dispersing the carboxylated graphene oxide in a double solvent consisting of dimethylacetamide and triethyl phosphate, then adding polyvinylidene fluoride, and mechanically stirring and dissolving to obtain a casting solution;
step nine: and (3) crushing the nano high-tension master batch, adding water to prepare a nano solution, pouring the nano solution into the graphene oxide aqueous solution, and uniformly mixing.
2. The graphene ultrafiltration membrane and the preparation method thereof according to claim 1 are characterized in that: and in the first step, putting the beaker filled with the mixed solution of concentrated sulfuric acid and sodium nitrate into an ice bath box, cooling, adding crystalline flake graphite, and uniformly stirring.
3. The graphene ultrafiltration membrane and the preparation method thereof according to claim 1 are characterized in that: and step three, adding deionized water to terminate the reaction, simultaneously adding hydrogen peroxide, centrifugally washing the product by using dilute salt, and drying in a vacuum oven to obtain the graphite oxide powder.
4. The graphene ultrafiltration membrane and the preparation method thereof according to claim 1 are characterized in that: and adding cobalt nitrate hexahydrate into the mixed solution in the fourth step, stirring until the cobalt nitrate hexahydrate is uniformly mixed, refluxing and heating the mixture, washing the mixture with ethanol, and finally drying the mixture in a vacuum oven to obtain the graphene oxide.
5. The graphene ultrafiltration membrane and the preparation method thereof according to claim 1 are characterized in that: in the sixth step, the polyethylene glycol can increase the pore-forming rate of the membrane and the water permeability of the ultrafiltration membrane.
6. The graphene ultrafiltration membrane and the preparation method thereof according to claim 1 are characterized in that: and seventhly, adding sodium hydroxide and chloroacetic acid into the aqueous solution of the graphene oxide, continuing to perform ultrasonic treatment for three hours, repeatedly washing the obtained mixed solution with deionized water until the pH of the effluent is 7.0, filtering, drying the obtained filter cake at 50 ℃, and drying to obtain the carboxylated graphene oxide.
7. The graphene ultrafiltration membrane and the preparation method thereof according to claim 1 are characterized in that: in the ninth step, the nano high-tension master batch is firstly prepared into nano high-tension powder through a pulverizer, and then the nano high-tension powder is added with water to prepare a nano high-tension solution.
8. The graphene ultrafiltration membrane and the preparation method thereof according to claim 1 are characterized in that: naturally cooling the obtained casting solution to room temperature, and scraping the film on a glass plate; and then immersing the glass plate with the scraping film into a gel water bath at 20-30 ℃ for phase separation to form a film, soaking the film for 3-5 days by using deionized water, taking out the film, and naturally airing the film in the air to obtain the graphene ultrafiltration film.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104028115A (en) * | 2014-06-03 | 2014-09-10 | 上海应用技术学院 | Carboxylation graphene oxide/polyvinylidene fluoride compiste ultrafiltration membrane and preparation method thereof |
| CN105214511A (en) * | 2015-09-18 | 2016-01-06 | 浙江工商大学 | A kind of Nano Silver/Graphene/Kynoar hybrid membranes and preparation method thereof |
| CN110917893A (en) * | 2019-11-25 | 2020-03-27 | 西安戴森电子技术有限公司 | Preparation method of graphene ultrafiltration membrane |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104028115A (en) * | 2014-06-03 | 2014-09-10 | 上海应用技术学院 | Carboxylation graphene oxide/polyvinylidene fluoride compiste ultrafiltration membrane and preparation method thereof |
| CN105214511A (en) * | 2015-09-18 | 2016-01-06 | 浙江工商大学 | A kind of Nano Silver/Graphene/Kynoar hybrid membranes and preparation method thereof |
| CN110917893A (en) * | 2019-11-25 | 2020-03-27 | 西安戴森电子技术有限公司 | Preparation method of graphene ultrafiltration membrane |
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