CN114797472A - Forward osmosis composite membrane prepared by magnetic field assisted thermally induced phase separation method and preparation method thereof - Google Patents
Forward osmosis composite membrane prepared by magnetic field assisted thermally induced phase separation method and preparation method thereof Download PDFInfo
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Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D61/00—Processes of separation using semi-permeable membranes, e.g. dialysis, osmosis or ultrafiltration; Apparatus, accessories or auxiliary operations specially adapted therefor
- B01D61/002—Forward osmosis or direct osmosis
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0009—Organic membrane manufacture by phase separation, sol-gel transition, evaporation or solvent quenching
- B01D67/0018—Thermally induced processes [TIPS]
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/12—Composite membranes; Ultra-thin membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/24—Mechanical properties, e.g. strength
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/36—Hydrophilic membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/06—Organic material
- B01D71/56—Polyamides, e.g. polyester-amides
Abstract
The invention belongs to the technical field of membrane separation, and discloses a forward osmosis composite membrane prepared by a magnetic field assisted thermally induced phase separation method and a preparation method thereof. The invention adopts a magnetic field assisted thermally induced phase separation method to prepare a nano particle/polymer hybrid base film, and then adopts an interface polymerization method to form a polyamide ultrathin separation layer on the surface of the base film, thereby forming the forward osmosis composite film. Compared with the forward osmosis membrane prepared by the existing method, the contact angle of the polymer-based membrane prepared by the method is reduced to 63.5 degrees from the original 81.9 degrees, the permeation flux of the composite forward osmosis membrane is increased by 1 time, and the reverse salt flux is also increased. The method lays a foundation for developing the forward osmosis composite membrane with high hydrophilicity, high porosity, small permeation resistance and high strength.
Description
Technical Field
The invention relates to the technical field of membrane separation, in particular to a forward osmosis composite membrane prepared by a magnetic field assisted thermally induced phase separation method and a preparation method thereof.
Background
The Forward Osmosis (FO) membrane separation technique is a separation technique that mimics the phenomenon of osmosis in nature. In the process, osmotic pressure on two sides of the membrane is used as a driving force, and water molecules can automatically penetrate through the membrane from a raw material liquid to reach a liquid drawing side. However, the forward osmosis membrane has a large development space for its preparation due to its short development time. According to the separation characteristics of forward osmosis, the development of a membrane with high hydrophilicity, high porosity and small permeation resistance is a technical difficulty to be overcome urgently.
The forward osmosis membrane is generally composed of a porous polymer-based membrane and an ultrathin polyamide separation layer, and mainly plays a role in retaining salt due to the thin thickness of the polyamide separation layer; while the hydrophilicity, porosity and permeation resistance of a forward osmosis membrane are largely dependent on the properties of the porous polymeric support layer. In addition, concentration polarization phenomena in forward osmosis, especially internal concentration polarization, can cause significant reductions in forward osmosis membrane water flux, resulting in actual flux well below theoretically expected values. Research shows that the concentration polarization effect can be obviously reduced by improving the hydrophilicity of the forward osmosis base membrane, so that the osmosis flux of the composite membrane is improved. Therefore, it is a technical problem to be solved to develop a high-performance forward osmosis membrane by using any membrane forming method to increase the hydrophilicity and porosity of the forward osmosis membrane and to reduce the permeation resistance.
To date, the most common method for preparing a forward osmosis support layer (base film) is non-solvent induced phase separation (NIPS). The method is that polymer and solvent are dissolved at a certain temperature to prepare homogeneous solution, then membrane casting solution is immersed in non-solvent, and the exchange of polymer in solvent-non-solvent initiates phase separation to form asymmetric separation membrane with compact skin layer. However, polymer films produced by the NIPS method generally have the disadvantages of low film-forming strength, poor hydrophilicity, and the like.
Thermal Induced Phase Separation (TIPS) is a membrane formation method invented by castro in 1980, a.j. of usa and applied for patent USP 4247498. The film forming mechanism is that the polymer and the diluent are dissolved at high temperature to form homogeneous solution, then the temperature is rapidly reduced in the film forming process, so that the casting solution is subjected to phase separation and solidification, and finally the diluent is extracted by using the extracting agent, thereby obtaining the porous film. The film prepared by the TIPS method has the advantages of easy regulation and control of the film forming process, high porosity, high film forming strength and the like. However, such polymeric films also generally suffer from poor hydrophilicity.
The blending modification method is adopted, namely hydrophilic inorganic nano particles are added into a membrane casting solution system, so that the hydrophilicity of the membrane can be effectively improved, but the inorganic nano particles are easy to agglomerate or aggregate in the membrane forming process, so that the separation performance of the membrane is reduced. For example, patent publication No. CN109888347A discloses the use of inorganic nanoparticles and phosphotungstic acid to modify sulfonated polyetheretherketone to improve the proton conductivity and alcohol barrier properties of the membrane.
Therefore, the development of a highly hydrophilic, highly porous, low permeation resistance, and high strength forward osmosis membrane has become a great need in the art.
Disclosure of Invention
In view of the above, the invention provides a forward osmosis composite membrane prepared by a magnetic field assisted thermally induced phase separation method and a preparation method thereof, and solves the problems of low membrane forming strength, poor hydrophilicity and poor separation performance of the existing forward osmosis composite membrane.
In order to achieve the purpose, the invention adopts the following technical scheme:
the invention provides a method for preparing a forward osmosis composite membrane by a magnetic field assisted thermally induced phase separation method, which comprises the following steps:
(1) mixing the nanoparticle dispersion liquid, the polymer and the diluent, and defoaming to obtain a membrane casting solution;
(2) and coating the casting solution on a substrate, curing to obtain a polymer-based membrane, and then preparing the membrane to obtain the forward osmosis composite membrane.
Preferably, the nanoparticle dispersion liquid is a mixed liquid of magnetic nanoparticles and a diluent; the mass-volume ratio of the magnetic nanoparticles to the diluent is 1-5 g: 10-50 mL; the magnetic nano particles are Fe 3 O 4 、Fe 2 O 3 、Fe 3 O 4 -TiO 2 And Fe 3 O 4 -one or more of GO.
Preferably, in the step (1), the mass ratio of the magnetic nanoparticles to the polymer to the diluent is 0.5-5: 10-50: 50-89.
Preferably, in the step (1), the polymer is one or more of polyvinylidene fluoride, polyacrylonitrile, cellulose acetate, polyether sulfone, polysulfone, polyvinyl chloride, polyethylene and polypropylene, and the molecular weight of the polymer is 50-600 kDa; the diluent is independently one or more of dimethylformamide, dimethylacetamide, N-methylpyrrolidone, triethyl phosphate, dioctyl sebacate, dodecanol, glycerol, gamma-butyrolactone, and dibutyl phthalate.
Preferably, in the step (1), the mixing temperature is 80-150 ℃, and the mixing time is 4-12 h; the defoaming temperature is 80-150 ℃, and the time is 4-24 h.
Preferably, in the step (2), the coating temperature is 10-50 ℃; the curing is carried out in a magnetic field, the magnetic field intensity of the curing is 0.05-0.5T, and the time is 30-180 s.
Preferably, in the step (2), the film formation includes the steps of: and sequentially soaking the polymer base membrane in an aqueous solution of m-phenylenediamine and a normal hexane solution of trimesoyl chloride to obtain the forward osmosis composite membrane.
Preferably, the mass concentration of the m-phenylenediamine aqueous solution is 1-4 wt%, and the mass concentration of the trimesoyl chloride n-hexane solution is 0.05-0.2 wt%; the soaking time in the aqueous solution of m-phenylenediamine is 30-120 s, and the soaking time in the n-hexane solution of trimesoyl chloride is 10-60 s.
Preferably, in the step (2), before film formation, the film obtained by standing in a magnetic field is sequentially extracted and washed to obtain a polymer-based film; the extractant used for extraction is absolute ethyl alcohol, and the extraction time is 4-10 h.
The invention also provides a forward osmosis composite membrane prepared by the method for preparing the forward osmosis composite membrane by the magnetic field assisted thermally induced phase separation method.
According to the technical scheme, compared with the prior art, the invention has the following beneficial effects:
the invention adopts the magnetic field assisted thermally induced phase separation method to prepare the forward osmosis composite membrane, and the method can effectively improve the hydrophilicity of the polymer-based membrane, thereby effectively reducing the concentration polarization phenomenon in the forward osmosis process and improving the osmosis flux of the forward osmosis composite membrane. Compared with the forward osmosis membrane prepared by the existing method, the contact angle of the polymer-based membrane prepared by the method is reduced to 63.5 degrees from the original 81.9 degrees, the permeation flux of the composite forward osmosis membrane is increased by 1 time, and the reverse salt flux is also increased. The forward osmosis composite membrane obtained by the invention has the characteristics of high hydrophilicity, high porosity, small permeation resistance and high strength.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic diagram of a magnetic field assisted thermally induced phase separation process for preparing a forward osmosis composite membrane according to the present invention;
FIG. 2 is a contact angle of a forward osmosis composite membrane obtained in example 1 of the present invention;
FIG. 3 is a contact angle of a forward osmosis composite membrane obtained in example 2 of the present invention;
FIG. 4 is a contact angle of a forward osmosis composite membrane obtained in example 3 of the present invention;
FIG. 5 is a contact angle of the forward osmosis composite membrane obtained in comparative example 1 of the present invention.
Detailed Description
The invention provides a method for preparing a forward osmosis composite membrane by a magnetic field assisted thermally induced phase separation method, which comprises the following steps:
(1) mixing the nanoparticle dispersion liquid, the polymer and the diluent, and defoaming to obtain a membrane casting solution;
(2) and coating the casting solution on a substrate, curing to obtain a polymer-based membrane, and then preparing the membrane to obtain the forward osmosis composite membrane.
In the invention, the nanoparticle dispersion liquid is a mixed liquid of magnetic nanoparticles and a diluent; the mass-volume ratio of the magnetic nanoparticles to the diluent is preferably 1-5 g: 10 to 50mL, more preferably 2 to 4 g: 15-35 mL; the magnetic nanoparticles are preferably Fe 3 O 4 、Fe 2 O 3 、Fe 3 O 4 -TiO 2 And Fe 3 O 4 -one or more of GO, further preferably Fe 2 O 3 And/or Fe 3 O 4 -GO。
In the present invention, the preparation of the nanoparticle dispersion liquid includes the steps of: ultrasonically mixing the magnetic nanoparticles with a diluent to uniformly disperse the magnetic nanoparticles in the diluent; the frequency of the ultrasonic mixing is preferably 19.5-30 kHz, and is further preferably 20-20.5 kHz; the time is preferably 30 to 120min, and more preferably 40 to 100 min.
In the invention, in the step (1), the mass ratio of the magnetic nanoparticles to the polymer to the diluent is preferably 0.5-5: 10-50: 50-89, and more preferably 2.5-4: 30-45: 70-79.
In the present invention, in the step (1), the polymer is preferably one or more of polyvinylidene fluoride, polyacrylonitrile, cellulose acetate, polyethersulfone, polysulfone, polyvinyl chloride, polyethylene and polypropylene, and is further preferably one or more of polyacrylonitrile, cellulose acetate, polyethersulfone and polysulfone; the molecular weight of the polymer is preferably 50-600 kDa, and more preferably 100-250 kDa; the diluent is independently preferably one or more of dimethylformamide, dimethylacetamide, N-methylpyrrolidone, triethyl phosphate, dioctyl sebacate, dodecanol, glycerol, γ -butyrolactone, and dibutyl phthalate, and is further preferably one or more of N-methylpyrrolidone, dioctyl sebacate, dodecanol, and glycerol.
In the invention, in the step (1), the mixing temperature is preferably 80-150 ℃, and more preferably 90-120 ℃; the time is preferably 4-12 h, and more preferably 6-10 h; the defoaming temperature is preferably 80-150 ℃, and more preferably 90-120 ℃; the time is preferably 4 to 24 hours, and more preferably 10 to 20 hours.
In the invention, in the step (2), the coating temperature is preferably 10-50 ℃, and more preferably 15-35 ℃; curing is carried out in a magnetic field, and the magnetic field intensity of curing is preferably 0.05-0.5T, and more preferably 0.15-0.45T; the time is preferably 30 to 180 seconds, and more preferably 50 to 100 seconds.
In the present invention, the direction of the magnetic field is parallel to the substrate, and the substrate may be a common substrate such as a glass plate.
In the present invention, in the step (2), the film formation includes the steps of: and sequentially soaking the polymer base membrane in an aqueous solution of m-phenylenediamine and a normal hexane solution of trimesoyl chloride to obtain the forward osmosis composite membrane.
In the invention, the mass concentration of the m-phenylenediamine aqueous solution is preferably 1 to 4 wt%, and more preferably 2 to 3.5 wt%; the mass concentration of the n-hexane solution of trimesoyl chloride is preferably 0.05 to 0.2 wt%, and more preferably 0.1 to 0.15 wt%; the soaking time in the m-phenylenediamine aqueous solution is preferably 30 to 120s, and more preferably 50 to 110 s; the soaking time in the n-hexane solution of trimesoyl chloride is preferably 10 to 60s, and more preferably 20 to 50 s.
In the invention, in the step (2), before film making, the film obtained by standing and curing in a magnetic field is sequentially extracted and washed to obtain a polymer base film; the extractant used for extraction is absolute ethyl alcohol, and the extraction time is preferably 4-10 h, and further preferably 5-8 h.
In the present invention, the film formation is performed in a film formation frame; drying the membrane layer obtained by membrane preparation after the membrane preparation is finished to obtain a forward osmosis composite membrane; the drying temperature is preferably 50-80 ℃, and further preferably 55-75 ℃; the time is preferably 3 to 10min, and more preferably 4 to 8 min.
The invention also provides a forward osmosis composite membrane prepared by the method for preparing the forward osmosis composite membrane by the magnetic field assisted thermally induced phase separation method.
The invention provides a method for preparing a forward osmosis membrane by a magnetic field assisted thermal phase separation method. In the film making process, the external magnetic field can enable the magnetic nanoparticles to be uniformly dispersed on the surface of the polymer base film, so that the hydrophilicity of the base film is effectively improved, meanwhile, the film is formed by a thermally induced phase separation method, the problem that the large cavity structure of the film section is caused by the excessively high solvent-non-solvent exchange rate in the traditional non-solvent induced phase separation method is ingeniously avoided, the pore diameter and the porosity of the formed film can be more effectively regulated and controlled, and the strength and the separation performance of the base film are further improved. Thereby improving the strength, service life and separation performance of the forward osmosis membrane.
The technical solutions provided by the present invention are described in detail below with reference to examples, but they should not be construed as limiting the scope of the present invention.
The hydrophilicity of the forward osmosis composite membranes obtained in the following examples and comparative examples was characterized by contact angle, and the separation performance of the composite membranes was characterized by permeation flux and reverse salt flux;
contact angle: the contact angle (contact angle) is the tangent of the gas-liquid interface at the intersection of the gas, liquid and solid phases, and the angle θ between the liquid side and the solid-liquid boundary line of the tangent is an important parameter for characterizing the hydrophilicity of the membrane surface. The measuring method comprises drying the prepared membrane, cutting into rectangular sample strips, fixing the membrane on a glass slide with the right side facing upwards by using a double-sided adhesive tape, dripping 1.5 mu L of deionized water on the surface of the membrane, and measuring the contact angle of the membrane. And measuring 5-8 different positions of each sample, and taking the arithmetic average value to obtain the average contact angle of the film.
Forward osmosis membrane performance evaluation: taking 1mol/L NaCl as a drawing liquid and deionized water as a raw material liquid. The forward osmosis membrane permeation flux is the increase in volume of draw solution per unit membrane area per unit time, as shown in equation (1). The reverse salt flux is the mass of salt flowing from the concentrate side to the dilute side per unit time and per membrane area, as shown in equation (2).
In the formula J W Permeation flux (L.m) -2 ·h -1 )；
ΔV draw -the volume increase (L) of the draw solution;
A m effective filtration area of the membrane (m) 2 )；
Δ t-filtration time (h).
In the formula J S Reverse salt flux (g.m) -2 ·h -1 )；
Δ(C t ×V t ) -mass increase of salt on the fresh water side (g);
A m effective filtration area of the membrane (m) 2 )；
Δ t-filtration time (h).
Example 1
In a first step, 2g of Fe 3 O 4 Dissolving in 20g of dimethylacetamide, and ultrasonically dispersing for 60min under the condition that the frequency is 25kHz to uniformly disperse the nanoparticles in the diluent to obtain a nanoparticle dispersion liquid;
secondly, adding the nanoparticle dispersion liquid obtained in the first step, 25 wt% of polyvinylidene fluoride, 39 wt% of dimethylacetamide and 25 wt% of dodecanol into a reaction kettle, heating to 100 ℃, and uniformly stirring for 6 hours to form a homogeneous casting solution;
thirdly, standing the homogeneous phase membrane casting solution obtained in the second step in a reaction kettle at a constant temperature of 85 ℃ for 8 hours, and removing bubbles in the membrane casting solution to obtain the membrane casting solution;
fourthly, pouring the casting solution obtained in the third step on one side of a glass plate at 25 ℃, coating the film by using a scraper, and then standing the film in a magnetic field of 0.1T for 30 seconds (the direction of the magnetic field is parallel to the glass plate);
step five, immersing the membrane obtained in the step four in absolute ethyl alcohol for 4 hours to extract the diluent in the membrane to obtain a polymer-based membrane;
sixthly, immersing the polymer base film obtained in the fifth step into deionized water for repeated washing for later use;
seventhly, placing the polymer base film obtained in the sixth step in a film making frame, pouring 2.0 wt% of m-phenylenediamine aqueous solution on the surface of the base film, soaking for 60s, and pouring out the aqueous phase solution; then 0.1 wt% of trimesoyl chloride n-hexane solution is poured on the surface of the basement membrane and soaked for 30 s. And finally, taking the membrane out of the frame, and treating in a 60 ℃ oven for 5min to obtain the forward osmosis composite membrane.
In the forward osmosis composite membrane prepared in example 1, the contact angle of the base membrane was 68.3 °, and when 1mol/L NaCl was used as the draw solution and deionized water was used as the raw material solution, the permeation flux was 25.8L · m -2 ·h -1 Reverse direction salt solutionThe amount was 6.3 g.m -2 ·h -1 。
Example 2
The differences from example 1 are: in the first step Fe 3 O 4 The amount of the additive was 4g, and the same procedure as in example 1 was repeated.
In the forward osmosis composite membrane prepared in example 2, the contact angle of the base membrane was 63.5 °, and when 1mol/L NaCl was used as the draw solution and deionized water was used as the raw material solution, the permeation flux was 33.9L · m -2 ·h -1 Reverse salt flux of 7.5 g.m -2 ·h -1 。
Example 3
In a first step, 2g of Fe 3 O 4 Adding 20g of dibutyl phthalate, and performing ultrasonic dispersion for 60min under the condition that the frequency is 23kHz to uniformly disperse the nanoparticles in the solvent to obtain a nanoparticle dispersion liquid;
secondly, adding the nanoparticle dispersion liquid obtained in the first step, 25 wt% of polyvinylidene fluoride, 49 wt% of dibutyl phthalate and 15 wt% of dodecanol into a reaction kettle, and uniformly stirring for 6 hours at 100 ℃ to form a homogeneous casting solution;
thirdly, standing the homogeneous phase membrane casting solution obtained in the second step in a reaction kettle at a constant temperature of 110 ℃ for 10 hours, and removing bubbles in the membrane casting solution to obtain the membrane casting solution;
fourthly, pouring the casting solution obtained in the third step on one side of a glass plate at 25 ℃ and coating the film by using a scraper, and then placing the glass plate in a 0.2T magnetic field for standing for 30s (the direction of the magnetic field is parallel to the glass plate);
fifthly, immersing the membrane obtained in the fourth step in absolute ethyl alcohol for 4 hours to extract the diluent in the membrane to obtain a polymer-based membrane;
sixthly, immersing the polymer base film obtained in the fifth step into deionized water for repeated washing for later use;
seventhly, placing the polymer base film obtained in the sixth step into a film-making frame, pouring 2 wt% of m-phenylenediamine aqueous solution on the surface of the base film, soaking for 60s, and pouring out the aqueous phase solution; then 0.1 wt% of trimesoyl chloride n-hexane solution is poured on the surface of the basement membrane and soaked for 30 s. And finally, taking the membrane out of the frame, and treating in a 60 ℃ oven for 5min to obtain the forward osmosis composite membrane.
In the forward osmosis membrane prepared in example 3, the contact angle of the base membrane was 69.6 °, and when 1mol/L NaCl was used as the draw solution and deionized water was used as the raw material solution, the permeation flux was 24.9L · m -2 ·h -1 Reverse salt flux of 6.9 g.m -2 ·h -1 。
Comparative example 1
Firstly, adding 25 wt% of polyvinylidene fluoride, 60 wt% of dibutyl phthalate and 15 wt% of dodecanol into a reaction kettle, and uniformly stirring for 6 hours at 100 ℃ to form a homogeneous membrane casting solution;
step two, standing the homogeneous phase membrane casting solution obtained in the step one in a reaction kettle at a constant temperature of 90 ℃ for 8 hours, and removing bubbles in the membrane casting solution to obtain the membrane casting solution;
thirdly, pouring the casting solution obtained in the second step on one side of a glass plate with the temperature of 25 ℃, coating the glass plate with a scraper, and standing the glass plate at room temperature for 30 s:
fourthly, immersing the membrane obtained in the third step into absolute ethyl alcohol for 4 hours to extract the diluent in the membrane to obtain a polymer-based membrane;
step five, immersing the polymer base film obtained in the step four into deionized water for repeated washing for later use;
sixthly, placing the polymer base film obtained in the fifth step into a film-making frame, pouring 2 wt% of m-phenylenediamine aqueous solution on the surface of the base film, soaking for 60s, and pouring out the aqueous phase solution; then 0.1 wt% of trimesoyl chloride n-hexane solution is poured on the surface of the basement membrane and soaked for 30 s. And finally, taking the membrane out of the frame, and treating in a 60 ℃ oven for 5min to obtain the forward osmosis composite membrane.
The contact angle of the base membrane of the forward osmosis membrane prepared by the comparative example is 82.2 degrees, and when 1mol/L NaCl is used as an extraction liquid and deionized water is used as a raw material liquid, the permeation flux is 15.3 L.m -2 ·h -1 Reverse salt flux of 5.5 g.m -2 ·h -1 。
As can be seen from comparison between examples 1-3 and comparative example 1, compared with the forward osmosis membrane prepared by the existing method, the contact angle of the polymer-based membrane prepared by the method disclosed by the invention is reduced to 63.5-69.6 degrees from the original 81.9 degrees, the permeation flux of the composite forward osmosis membrane is increased by 1 time, and the reverse salt flux is also increased.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (10)
1. A method for preparing a forward osmosis composite membrane by a magnetic field assisted thermally induced phase separation method is characterized by comprising the following steps:
(1) mixing the nanoparticle dispersion liquid, the polymer and the diluent, and defoaming to obtain a membrane casting solution;
(2) and coating the casting solution on a substrate, curing to obtain a polymer-based membrane, and then preparing the membrane to obtain the forward osmosis composite membrane.
2. The method for preparing a forward osmosis composite membrane according to claim 1, wherein the nanoparticle dispersion liquid is a mixed liquid of magnetic nanoparticles and a diluent; the mass volume ratio of the magnetic nanoparticles to the diluent is 1-5 g: 10-50 mL; the magnetic nano particles are Fe 3 O 4 、Fe 2 O 3 、Fe 3 O 4 -TiO 2 And Fe 3 O 4 -one or more of GO.
3. The method for preparing the forward osmosis composite membrane by the magnetic field assisted thermally induced phase separation method according to claim 2, wherein in the step (1), the mass ratio of the magnetic nanoparticles to the polymer to the diluent is 0.5-5: 10-50: 50-89.
4. The method for preparing the forward osmosis composite membrane by the magnetic field assisted thermal phase separation method according to claim 1 or 2, wherein in the step (1), the polymer is one or more of polyvinylidene fluoride, polyacrylonitrile, cellulose acetate, polyether sulfone, polysulfone, polyvinyl chloride, polyethylene and polypropylene, and the molecular weight of the polymer is 50-600 kDa; the diluent is independently one or more of dimethylformamide, dimethylacetamide, N-methylpyrrolidone, triethyl phosphate, dioctyl sebacate, dodecanol, glycerol, gamma-butyrolactone, and dibutyl phthalate.
5. The method for preparing the forward osmosis composite membrane by the magnetic field assisted thermally induced phase separation method according to any one of claims 1 to 3, wherein in the step (1), the mixing temperature is 80-150 ℃ and the mixing time is 4-12 h; the defoaming temperature is 80-150 ℃, and the time is 4-24 h.
6. The method for preparing the forward osmosis composite membrane by the magnetic field assisted thermally induced phase separation method according to claim 5, wherein in the step (2), the coating temperature is 10-50 ℃; the curing is carried out in a magnetic field, the magnetic field intensity of the curing is 0.05-0.5T, and the time is 30-180 s.
7. The method for preparing a forward osmosis composite membrane according to claim 6, wherein in the step (2), membrane preparation comprises the following steps: and sequentially soaking the polymer base membrane in an aqueous solution of m-phenylenediamine and a normal hexane solution of trimesoyl chloride to obtain the forward osmosis composite membrane.
8. The method for preparing the forward osmosis composite membrane by the magnetic field assisted thermally induced phase separation method according to claim 7, wherein the mass concentration of the m-phenylenediamine aqueous solution is 1-4 wt%, and the mass concentration of the trimesoyl chloride n-hexane solution is 0.05-0.2 wt%; the soaking time in the aqueous solution of m-phenylenediamine is 30-120 s, and the soaking time in the n-hexane solution of trimesoyl chloride is 10-60 s.
9. The method for preparing a forward osmosis composite membrane according to the magnetic field assisted thermal phase separation method of claim 6 or 7, wherein in the step (2), before membrane preparation, the membrane obtained by standing in the magnetic field is sequentially extracted and washed to obtain a polymer-based membrane; the extractant used for extraction is absolute ethyl alcohol, and the extraction time is 4-10 h.
10. The forward osmosis composite membrane prepared by the method for preparing the forward osmosis composite membrane by the magnetic field assisted thermally induced phase separation method according to any one of claims 1 to 9.
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Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090272692A1 (en) * | 2008-05-05 | 2009-11-05 | Nanoh20 Inc. | Thin film membranes with additives for forward and pressure retarded osmosis |
| CN105771703A (en) * | 2016-03-15 | 2016-07-20 | 北京工业大学 | Preparation method of polyethersulfone-based composite positive permeable membrane |
| CN106861467A (en) * | 2015-12-13 | 2017-06-20 | 中国科学院大连化学物理研究所 | A kind of titanium doped forward osmosis membrane of modified hydrophilic nanometer titanium dioxide and its preparation |
| CN107746527A (en) * | 2017-11-03 | 2018-03-02 | 桂林电子科技大学 | A kind of multiphase high molecular functional laminated film based on Thermal inactive technology and preparation method thereof |
| CN108543426A (en) * | 2018-04-19 | 2018-09-18 | 郑州轻工业学院 | The preparation method and application of pervaporation hybrid membrane under a kind of induced by magnetic field |
| CN109289548A (en) * | 2017-07-24 | 2019-02-01 | 天津工业大学 | A kind of preparation method of forward osmosis membrane |
| CN109758907A (en) * | 2019-02-25 | 2019-05-17 | 陕西省石油化工研究设计院 | A kind of method that LBL self-assembly interfacial polymerization prepares compound forward osmosis membrane |
| CN110052169A (en) * | 2019-04-25 | 2019-07-26 | 武汉大学 | A kind of method that magnetic carbon nano-tube is modified to complex reverse osmosis membrane |
| CN111589310A (en) * | 2020-04-22 | 2020-08-28 | 浙江大学宁波理工学院 | Strong anti-pollution composite gradient ultrafiltration membrane and preparation method thereof |
| US20220008867A1 (en) * | 2018-09-18 | 2022-01-13 | Valorbec, S.E.C. | Membranes for forward osmosis and membrane distillation and process of treating fracking wastewater |
-
2022
- 2022-05-20 CN CN202210548545.0A patent/CN114797472A/en active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090272692A1 (en) * | 2008-05-05 | 2009-11-05 | Nanoh20 Inc. | Thin film membranes with additives for forward and pressure retarded osmosis |
| CN106861467A (en) * | 2015-12-13 | 2017-06-20 | 中国科学院大连化学物理研究所 | A kind of titanium doped forward osmosis membrane of modified hydrophilic nanometer titanium dioxide and its preparation |
| CN105771703A (en) * | 2016-03-15 | 2016-07-20 | 北京工业大学 | Preparation method of polyethersulfone-based composite positive permeable membrane |
| CN109289548A (en) * | 2017-07-24 | 2019-02-01 | 天津工业大学 | A kind of preparation method of forward osmosis membrane |
| CN107746527A (en) * | 2017-11-03 | 2018-03-02 | 桂林电子科技大学 | A kind of multiphase high molecular functional laminated film based on Thermal inactive technology and preparation method thereof |
| CN108543426A (en) * | 2018-04-19 | 2018-09-18 | 郑州轻工业学院 | The preparation method and application of pervaporation hybrid membrane under a kind of induced by magnetic field |
| US20220008867A1 (en) * | 2018-09-18 | 2022-01-13 | Valorbec, S.E.C. | Membranes for forward osmosis and membrane distillation and process of treating fracking wastewater |
| CN109758907A (en) * | 2019-02-25 | 2019-05-17 | 陕西省石油化工研究设计院 | A kind of method that LBL self-assembly interfacial polymerization prepares compound forward osmosis membrane |
| CN110052169A (en) * | 2019-04-25 | 2019-07-26 | 武汉大学 | A kind of method that magnetic carbon nano-tube is modified to complex reverse osmosis membrane |
| CN111589310A (en) * | 2020-04-22 | 2020-08-28 | 浙江大学宁波理工学院 | Strong anti-pollution composite gradient ultrafiltration membrane and preparation method thereof |
Non-Patent Citations (1)
| Title |
|---|
| 刘文娟: "热致相分离法制备聚偏氟乙烯微孔膜的研究进展", 《中国环境科学学会学术年会论文集》 * |
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