CN115445453B - Method for preparing superhigh flux superhydrophobic PVDF membrane by solute solvent co-crystallization - Google Patents
Method for preparing superhigh flux superhydrophobic PVDF membrane by solute solvent co-crystallization Download PDFInfo
- Publication number
- CN115445453B CN115445453B CN202211081016.0A CN202211081016A CN115445453B CN 115445453 B CN115445453 B CN 115445453B CN 202211081016 A CN202211081016 A CN 202211081016A CN 115445453 B CN115445453 B CN 115445453B
- Authority
- CN
- China
- Prior art keywords
- pvdf
- solution
- membrane
- low crystallinity
- super
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- 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
- B01D71/30—Polyalkenyl halides
- B01D71/32—Polyalkenyl halides containing fluorine atoms
- B01D71/34—Polyvinylidene fluoride
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2325/00—Details relating to properties of membranes
- B01D2325/38—Hydrophobic membranes
Abstract
The invention discloses a method for preparing an ultra-high flux super-hydrophobic PVDF membrane by utilizing solute solvent co-crystallization, which comprises the following steps: (1) preparation of PVDF with low crystallinity: PVDF is soaked in alkaline methanol solution for reaction, and the reacted mixed solution is added into NaHSO 3 Standing in an aqueous solution, filtering, washing, and freeze-drying to obtain PVDF with low crystallinity; (2) PVDF super-hydrophobic membrane preparation: and (3) blending PVDF and PVDF with low crystallinity, dissolving in dimethyl sulfoxide to form PVDF solution, standing, spreading on a flat plate to form a coating, immersing in liquid nitrogen, immersing in ice water bath, taking out the PVDF film, and naturally airing. The super-hydrophobic PVDF membrane prepared by the invention has stable performance and high permeation flux, and can be manufactured and applied in large scale.
Description
Technical Field
The invention relates to the technical field of membranes, in particular to a method for preparing an ultra-high flux super-hydrophobic PVDF membrane by utilizing solute solvent co-crystallization.
Background
Oil-water separation is always a great challenge in water treatment, and the appearance of the super-hydrophobic membrane provides a brand-new path for oil-water separation. The water contact angle of the superhydrophobic film is required to be greater than 150 ° and the sliding angle is less than 10 °. The effective separation of oil and water is realized by size screening, and more importantly, the selective permeation of oil and water by the surface of the membrane is realized, namely, the water is flicked off the surface of the membrane, and oil substances can permeate the surface of the membrane. The superhydrophobic film exhibits high separation efficiency even when treating emulsifier-stabilized oily wastewater. Therefore, the efficient preparation of the superhydrophobic film is particularly important, and mainly surrounds two technical points: firstly, using a substance with low surface energy as a raw material; and secondly, constructing a high roughness structure. Based on the two points, many scholars succeeded in preparing the superhydrophobic films. However, the current preparation of the super-hydrophobic membrane is faced with the problems of complex preparation process, higher production cost, poor stability and the like, and in addition, the preparation mode of using the polyfluoro group as the low surface energy coating modification even generates environmental risks. Thus, there is still a need for a method of preparing highly efficient superhydrophobic films.
PVDF membranes are widely used in filtration units for wastewater treatment because of their excellent chemical and thermodynamic stability. PVDF also has a relatively low surface free energy and is therefore often used to prepare superhydrophobic films, but is currently limited by the preparation process and permeation flux is relatively low. The current superhydrophobic modification for PVDF membranes is mainly blended with inorganic particulates or with polyfluoro polymers. The disadvantage is that the stability of the material is relatively poor, the blended substance is easy to fall off, and environmental risks are easily caused. Other methods, such as an electrostatic spinning method, a template method and the like, are relatively complex to operate, and experimental variables are relatively difficult to control. In view of this, it is necessary to provide a simple and efficient preparation method of the superhydrophobic PVDF membrane to solve the above problems, so that the superhydrophobic PVDF membrane has stable superhydrophobic performance and relatively high permeation flux.
Disclosure of Invention
In order to solve the technical problems of complex preparation process and poor stability of the existing superhydrophobic membrane, the invention provides a method for preparing the superhigh flux superhydrophobic polyvinylidene fluoride (PVDF) membrane by using solute solvent co-crystallization, which is very simple and convenient, does not need additional modification, and the prepared membrane has stable superhydrophobic property and superhigh permeation flux. The low crystallinity PVDF particles are used to assist in structuring the graded two-dimensional roughness structure to form a rough surface. And simultaneously, the solvent (dimethyl sulfoxide) is quickly crystallized by utilizing liquid nitrogen freezing to form an open membrane pore canal for increasing the flux of the super-hydrophobic PVDF membrane. The preparation method of the superhydrophobic film is relatively simple, the variables to be controlled are relatively few, the repeatability is high, and the performance of the film is more stable.
The method for preparing the superhigh flux superhydrophobic PVDF membrane specifically comprises the following steps of
(1) Low crystallinity PVDF preparation: the initial PVDF powder is soaked in alkaline methanol solution, and stirred at 50-70 ℃ for reaction for 1-5h (e.g. 1h,2h,3h,4h,5 h), and the color of the mixed solution changes from white to red to dark brown. Transferring the reacted mixtureTo NaHSO 3 And (3) standing for 1-3h in an aqueous solution (acidic). And filtering the modified PVDF in the mixed solution by using a vacuum pump, washing the PVDF to be neutral by using deionized water, and freeze-drying to obtain PVDF powder with low crystallinity.
(2) Preparing a PVDF super-hydrophobic membrane: blending the initial PVDF powder and the PVDF powder with low crystallinity in a mass ratio of 4-1:1 (for example, 4:1,3:1,2:1 and 1:1), dissolving in dimethyl sulfoxide (DMSO), heating and stirring at 60-80 ℃ until the PVDF powder and the PVDF powder are completely mixed to form a PVDF solution, and standing to remove bubbles. The solution is coated on a flat plate in a scraping way to form a coating, then the flat plate is immersed in liquid nitrogen rapidly for 1-5s until complete crystallization, then the flat plate is transferred into an ice water bath (0 ℃) to remove a DMSO template, the PVDF membrane is taken out, and the PVDF super-hydrophobic membrane can be obtained after natural airing.
Based on the above technical scheme, preferably, in the step (1), the concentration of the alkaline methanol solution is 4-6%, preferably 5% by weight, and the alkali in the alkaline methanol solution is potassium hydroxide, and the preparation method of the alkaline methanol solution is as follows: the potassium hydroxide is dissolved in methanol to prepare the aqueous emulsion.
Based on the above technical solution, preferably, in the step (1), the ratio of the PVDF powder to the alkaline methanol solution is 5-15g:200mL, preferably 10g:200mL.
Based on the above technical solution, preferably, in step (1), the NaHSO 3 The concentration of the aqueous solution is 1 to 2wt%, preferably 1.2wt%.
Based on the above technical scheme, preferably, in the step (1), the alkaline methanol solution is mixed with NaHSO 3 The volume ratio of the aqueous solution is 1:1.
Based on the above technical scheme, preferably, in the step (2), the total concentration of the PVDF powder of the PVDF solution and the PVDF powder with low crystallinity is 5-7wt%, preferably 6wt%.
Based on the technical scheme, in the step (2), preferably, the standing time is 12-24h.
Based on the above technical solution, preferably, in step (2), the plate is made of glass, aluminum or copper.
Based on the above technical solution, it is preferable that in the step (2), the thickness of the coating layer is 100 to 250 μm, preferably 200 μm.
Based on the above technical scheme, preferably, in the step (2), the time of immersing in the ice water bath is more than 12 hours until the crystal template is completely removed. Based on the above technical solution, it is preferable that in the step (2), the mass ratio of the initial PVDF powder to the low crystallinity PVDF powder is 3:1.
Advantageous effects
The super-hydrophobic PVDF membrane is formed by co-crystallizing a solute (the blend of initial PVDF powder and low-crystallinity PVDF powder modified by hot alkali) and a solvent (DMSO) under the freezing of liquid nitrogen. Crystallization of the solute yields a graded two-dimensional coarse structure and solvent crystallization yields an ultra-high permeate flux to the membrane. Compared with the method of adding inorganic particles, the method utilizes the blending of the homologous organic substances, so that the mixing is more uniform, and the surface property is more stable. Compared with the method for adding the polyfluoro polymer, the method is relatively more environment-friendly by using PVDF (with lower fluorine content) modified by hot alkali. Generally, the preparation method is easier than most of the current researches, the variables required to be controlled are relatively less, the repeatability is strong, and the prepared super-hydrophobic PVDF membrane has stable performance and high permeation flux and can be manufactured and applied in large scale.
Drawings
FIG. 1 is an illustration of a preparation process in which the present invention is concerned; wherein a is the preparation process of the PVDF powder with low crystallinity; b description of the process for preparing membranes by solute-solvent co-crystallization.
Fig. 2 is a surface contact angle plot of the low crystallinity PVDF powder prepared in example 1.
FIG. 3 is an electron micrograph of the surface of the low crystallinity PVDF powder prepared in example 1, wherein PVDF-0 was prepared by heating and stirring at 60℃for 0h, PVDF-1 was prepared by heating and stirring at 60℃for 1h, PVDF-2 was prepared by heating and stirring at 60℃for 2h, PVDF-3 was prepared by heating and stirring at 60℃for 3h, PVDF-4 was prepared by heating and stirring at 60℃for 4h, and PVDF-5 was prepared by heating and stirring at 60℃for 5 h.
FIG. 4 is a graph of contact angles of PVDF film prepared in different proportions in example 1, wherein PVDF@PVDF-4 is a blend of PVDF with PVDF powder modified for 4 hours (PVDF of low crystallinity obtained by heating and stirring at 60 ℃ C. For 4 hours).
FIG. 5 is an electron microscopic view of PVDF film prepared in different proportions of example 1, wherein the PVDF with low crystallinity is PVDF with low crystallinity obtained by heating and stirring at 60℃for 4 hours.
FIG. 6 is a graph of the sliding angle test dynamic process for the PVDF membrane side prepared in example 1, wherein a is a pure PVDF membrane, no rolling occurs; b is the surface of the superhydrophobic film obtained by blending PVDF and PVDF powder modified for 4 hours (PVDF with low crystallinity obtained by heating and stirring for 4 hours at 60 ℃) in a mass ratio of 3:1, and rolling occurs.
FIG. 7 is a graph depicting the acid-base resistance and thermodynamic stability of PVDF film prepared in example 1 (PVDF to modified 4h PVDF powder mass ratio of 3:1).
Fig. 8 is a cylinder filter diagram.
Fig. 9 shows the permeation flux of PVDF membranes by self gravity as driving force.
Detailed Description
The following non-limiting examples will enable those of ordinary skill in the art to more fully understand the invention and are not intended to limit the invention in any way.
The test methods described in the following examples, unless otherwise specified, are all conventional; the reagents and materials, unless otherwise specified, are commercially available.
Example 1
The preparation method of the solute solvent co-crystallization super-hydrophobic PVDF membrane comprises the following steps:
the first step: 10g PVDF was placed in 200mL alkaline methanol solution (5 wt% KOH in methanol), heated to 60℃and stirred (0, 1,2,3,4,5h respectively), and the mixture was placed in 200mL of LNaHSO 3 Soaking in aqueous solution (1.2 wt%) for 2 hr, filtering the modified PVDF in the mixed solution by using vacuum pump, cleaning the modified PVDF powder by using deionized water, and freeze-drying so as to obtain the invented PVDF powder with low crystallinity.
And a second step of: PVDF was blended with low crystallinity PVDF (4:1, 3:1,2:1,1:1 respectively) in DMSO (6 wt%), heated and stirred at 80℃for 12h until homogeneous, and then allowed to stand for 12h to remove air bubbles. The solution was knife-coated on a glass sheet (length. Times.width: 10 cm. Times.10 cm, thickness: 1 mm) to form a coating layer having a thickness of 200 μm, then the glass sheet was rapidly immersed in liquid nitrogen for about 3s, immersed in an ice-water bath for standing for 12 hours until the crystal template was completely removed, and then the PVDF film was taken out and naturally dried.
Example 2
The modified PVDF powder was knife-coated on a glass plate according to the preparation method of PVDF film in example 1, and after liquid nitrogen freezing crystallization, the glass plate was placed in an ice water bath to remove the template, and the surface of the low-crystallinity PVDF was obtained, so as to examine the possibility of preparing the low-crystallinity PVDF. The contact angle of the material surface is shown in fig. 2, the water contact angle of unmodified initial PVDF is about 130 degrees, the surface contact angles of the 1h and 2h modified materials are reduced along with the increase of the modification time, but when the modification time reaches 3h, the contact angle is obviously increased, the crystallinity of the PVDF is greatly reduced, the roughness of the material surface is increased by small spherical crystals, when the modification time reaches 4h and 5h, the material surface reaches the super-hydrophobic level, and the scanning electron microscope image of the material surface is shown in fig. 3. In summary, it is illustrated that PVDF particles of low crystallinity can be obtained by hot alkali modification to form a coarse superhydrophobic structure.
Example 3
In order to construct a stable super-hydrophobic PVDF membrane, we consider blending PVDF with modified PVDF for 4 hours (PVDF with low crystallinity obtained by heating and stirring at 60 ℃ for 4 hours), and constructing a super-hydrophobic PVDF membrane with a micro-nano layered structure, wherein the blending is carried out according to the proportion of (4:1, 3:1,2:1 and 1:1 respectively). The contact angle of the film surface was used to measure the superhydrophobic performance, and a superhydrophobic surface was obtained at a ratio of 3:1, as shown in fig. 4. The electron microscope image is shown as 5, the large spherical crystal is formed by initial PVDF, the small spherical crystal around the large spherical crystal is formed by PVDF modified for 4 hours, and the electron microscope image clearly reflects the surface morphology of the film. In order to ensure higher mechanical performance, 3:1 is selected as the optimal film making proportion, the sliding angle is measured by a self-made simple inclined plate, a high-speed camera is utilized to capture the dynamic process, the film starts to slide at an inclined plane of about 4 degrees, and the film has good super-hydrophobic performance, as shown in fig. 6.
Example 4
The stability of superhydrophobic was examined using the optimal ratio (3:1) of superhydrophobic film prepared in example 3. The contact angle was measured by soaking in an ethanol solution at pH (2, 4,6,8,10,12, respectively) for 24 hours, and as shown in FIG. 7, it was found that there was only a slight drop in pH at 10 and 12 (due to dehydrofluorination), but still above 140 ℃. The film exhibits extremely high tolerance and stability in an acidic environment. Then, the film is subjected to thermodynamic tests, and is placed for 2 hours in an environment (respectively at-196, -80, -25,25,50,75,100,125,150,175 ℃), and the contact angle of the film is found to be almost unchanged, so that the superhydrophobic film can still keep good superhydrophobic performance in a fluctuating temperature environment. In conclusion, the super-hydrophobic membrane has good acid environment resistance and thermodynamic stability.
Example 5
The gravity separation process is carried out by using the measuring cylinder type filter shown in fig. 8, wherein a membrane is clamped at the middle part, the upper part is used for containing the organic reagent, the lower part is used for containing the percolate, and the driving force is the gravity of the liquid. Membrane permeation performance was examined and several common organic reagents (dichloromethane (CH 2 Cl 2 ) Toluene (tolene), petroleum Ether (PE) and Isooctane (isoctane)) to examine the filtration performance of the membrane. The membrane (3:1) was found to be capable of performing permeation by gravity of only 6.5cm of liquid, with a permeation flux of up to 88000L/m for methylene chloride 2 H (effective filtration area of membrane: 0.64 cm) 2 ). The flux of toluene, petroleum ether and isooctane is higher than 45000L/m 2 H, see fig. 9. This shows that the PVDF membrane prepared by the invention has extremely high permeation flux.
Claims (10)
1. The method for preparing the superhigh flux superhydrophobic PVDF membrane is characterized by comprising the following steps:
(1) Low crystallinity PVDF preparation: soaking PVDF in alkaline methanol solution, stirring at 50-70deg.C for 1-5 hr, and adding the reacted mixture into NaHSO 3 Standing in water solution for 1-3 hr, filtering, washing, and freeze drying to obtain low crystalPVDF in degrees;
(2) Preparing a PVDF super-hydrophobic membrane: blending PVDF and PVDF with low crystallinity, dissolving in dimethyl sulfoxide, heating and stirring at 60-80deg.C to uniformity to form PVDF solution, and standing to remove bubbles; then scraping the PVDF solution on a flat plate to form a coating, immersing the flat plate in liquid nitrogen for 1-5s, immersing the flat plate in ice water bath to remove dimethyl sulfoxide, taking out the PVDF film, and naturally airing to obtain the PVDF super-hydrophobic film; wherein the mass ratio of PVDF to PVDF with low crystallinity is 4-1:1.
2. The method according to claim 1, wherein in the step (1), the concentration of the basic methanol solution is 4 to 6%, and the alkali in the basic methanol solution is potassium hydroxide.
3. The method of claim 1, wherein in step (1), the ratio of PVDF powder to alkaline methanol solution is 5-15g:200mL.
4. The method of claim 1, wherein in step (1), the NaHSO 3 The concentration of the aqueous solution is 1-2wt%.
5. The method according to claim 1, wherein in step (1), the basic methanol solution is mixed with NaHSO 3 The volume ratio of the aqueous solution is 1:1.
6. The method of claim 1, wherein in step (2), the PVDF solution is at a concentration of 5-7wt%.
7. The method of claim 1, wherein in step (2), the time of resting is 12-24 hours.
8. The method of claim 1, wherein in step (2), the plate is made of glass, aluminum or copper.
9. The method according to claim 1, wherein in step (2), the thickness of the coating is 100-250 μm.
10. The method according to claim 1, wherein in the step (2), the time for immersing in the ice water bath is 12 hours or longer.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211081016.0A CN115445453B (en) | 2022-09-05 | 2022-09-05 | Method for preparing superhigh flux superhydrophobic PVDF membrane by solute solvent co-crystallization |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211081016.0A CN115445453B (en) | 2022-09-05 | 2022-09-05 | Method for preparing superhigh flux superhydrophobic PVDF membrane by solute solvent co-crystallization |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN115445453A CN115445453A (en) | 2022-12-09 |
| CN115445453B true CN115445453B (en) | 2023-07-25 |
Family
ID=84302284
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202211081016.0A Active CN115445453B (en) | 2022-09-05 | 2022-09-05 | Method for preparing superhigh flux superhydrophobic PVDF membrane by solute solvent co-crystallization |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115445453B (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20070031330A (en) * | 2004-06-15 | 2007-03-19 | 가부시끼가이샤 구레하 | Hollow-fiber porous water filtration membrane of vinylidene fluoride resin and process for producing the same |
| WO2007119850A1 (en) * | 2006-04-19 | 2007-10-25 | Asahi Kasei Chemicals Corporation | Highly durable porous pvdf film, method of producing the same and washing method and filtration method using the same |
| EP1849516A1 (en) * | 2004-12-22 | 2007-10-31 | Dressel Pte. Ltd. Company | Membrane card and method for the production and use thereof |
| CN105126647A (en) * | 2015-09-10 | 2015-12-09 | 南京大学 | Preparation method for efficient oil-water separation composite ultrafiltration membrane |
| CN105289329A (en) * | 2015-11-14 | 2016-02-03 | 常州大学 | Preparation method of PVDF/nanometer TiO2 blending modified flat sheet membrane module |
| CN112973478A (en) * | 2020-02-25 | 2021-06-18 | 四川大学 | Temperature-sensitive super-hydrophilic membrane and preparation method thereof |
-
2022
- 2022-09-05 CN CN202211081016.0A patent/CN115445453B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR20070031330A (en) * | 2004-06-15 | 2007-03-19 | 가부시끼가이샤 구레하 | Hollow-fiber porous water filtration membrane of vinylidene fluoride resin and process for producing the same |
| EP1849516A1 (en) * | 2004-12-22 | 2007-10-31 | Dressel Pte. Ltd. Company | Membrane card and method for the production and use thereof |
| WO2007119850A1 (en) * | 2006-04-19 | 2007-10-25 | Asahi Kasei Chemicals Corporation | Highly durable porous pvdf film, method of producing the same and washing method and filtration method using the same |
| CN105126647A (en) * | 2015-09-10 | 2015-12-09 | 南京大学 | Preparation method for efficient oil-water separation composite ultrafiltration membrane |
| CN105289329A (en) * | 2015-11-14 | 2016-02-03 | 常州大学 | Preparation method of PVDF/nanometer TiO2 blending modified flat sheet membrane module |
| CN112973478A (en) * | 2020-02-25 | 2021-06-18 | 四川大学 | Temperature-sensitive super-hydrophilic membrane and preparation method thereof |
Non-Patent Citations (2)
| Title |
|---|
| Inhomogeneous Thermal Degradation of Poly(viny1idene fluoride) Crystallized from the Melt;Andrew J. Lovinger等;Macromolecules;第13卷(第4期);989-994 * |
| Study on vacuum membrane distillation (VMD) using FEP hollow fiber membrane;Kaikai Chen等;Desalination;第375卷;24–32 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN115445453A (en) | 2022-12-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Song et al. | A superhydrophilic cement-coated mesh: an acid, alkali, and organic reagent-free material for oil/water separation | |
| Liu et al. | One-step constructed ultrathin Janus polyamide nanofilms with opposite charges for highly efficient nanofiltration | |
| Rajasekhar et al. | Oil–water emulsion separation using ultrafiltration membranes based on novel blends of poly (vinylidene fluoride) and amphiphilic tri-block copolymer containing carboxylic acid functional group | |
| Wang et al. | Fabrication of highly ordered microporous thin films by PS-b-PAA self-assembly and investigation of their tunable surface properties | |
| Li et al. | Fabrication of PVDF hollow fiber membranes via integrated phase separation for membrane distillation | |
| CN103464006B (en) | Preparation of PDMS/PVDF (polydimethylsiloxane/polyvinylidene fluoride) blended microporous film | |
| Mu et al. | Fabrication of microporous membranes by a feasible freeze method | |
| CN103501883A (en) | Composite mixed matrix membranes for membrane distillation and related methods of manufacture | |
| Chang et al. | Preparation of bi-continuous Nylon-66 porous membranes by coagulation of incipient dopes in soft non-solvent baths | |
| CN102430343B (en) | Preparation method of flat polyvinylidene fluoride micro-filtration membrane | |
| Chang et al. | Effect of polar rotation on the formation of porous poly (vinylidene fluoride) membranes by immersion precipitation in an alcohol bath | |
| CN100490955C (en) | Method for producing composite type semi-permeable hydrophilic filter membrane | |
| CN107970789B (en) | Hydrophobic membrane with micro-nano structure surface functional layer and preparation method thereof | |
| CN1704152A (en) | Preparation of hydrophilic polyvinylidene fluoride microporous membrane | |
| CN105032211A (en) | Novel hydrophobic membrane and preparation method thereof | |
| CN114904404A (en) | Mixed matrix forward osmosis membrane based on MOF-808(Zr) and preparation method thereof | |
| CN106139937B (en) | High molecular weight hydrophilic Modified Membrane, preparation method and application | |
| CN115445453B (en) | Method for preparing superhigh flux superhydrophobic PVDF membrane by solute solvent co-crystallization | |
| Du et al. | Polymerizable ionic liquid copolymer P (MMA-co-BVIm-Br) and its effect on the surface wettability of PVDF blend membranes | |
| Lin et al. | Preparation of PVDF/PMMA composite membrane with green solvent for seawater desalination by gap membrane distillation | |
| CN106823857B (en) | Preparation method of PVDF-HFP hydrophobic membrane for membrane distillation | |
| CN101850217B (en) | Method for preparing skin-free homogeneous structural polyvinylidene fluoride transfer film | |
| Zhou et al. | Polyurethane membrane with temperature-and pH-Controllable permeability for amino-acids | |
| CN114957686B (en) | ZIF-8 structure, preparation method of dispersion liquid and application of dispersion liquid | |
| Ainscough et al. | Parametric optimisation for the fabrication of polyetherimide-sPEEK asymmetric membranes on a non-woven support layer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |