CN115253685A - Janus film and preparation method thereof - Google Patents

Janus film and preparation method thereof Download PDF

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CN115253685A
CN115253685A CN202210808935.7A CN202210808935A CN115253685A CN 115253685 A CN115253685 A CN 115253685A CN 202210808935 A CN202210808935 A CN 202210808935A CN 115253685 A CN115253685 A CN 115253685A
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hydrophobic
layer
electrostatic spraying
janus
organic
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CN115253685B (en
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彭靖俊
贾伟
罗仲元
王佳冕
张红斌
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Shenzhen National Research Institute of High Performance Medical Devices Co Ltd
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Shenzhen National Research Institute of High Performance Medical Devices Co Ltd
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    • 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
    • B01D61/36—Pervaporation; Membrane distillation; Liquid permeation
    • B01D61/364—Membrane distillation
    • 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
    • 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
    • B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
    • 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
    • B01D71/08—Polysaccharides
    • B01D71/12—Cellulose derivatives
    • B01D71/14—Esters of organic acids
    • B01D71/16—Cellulose acetate
    • 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
    • B01D71/26—Polyalkenes
    • 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
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    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
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    • B01D71/06—Organic material
    • B01D71/30—Polyalkenyl halides
    • B01D71/32—Polyalkenyl halides containing fluorine atoms
    • B01D71/36—Polytetrafluoroethene
    • 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
    • B01D71/40—Polymers of unsaturated acids or derivatives thereof, e.g. salts, amides, imides, nitriles, anhydrides, esters
    • B01D71/42—Polymers of nitriles, e.g. polyacrylonitrile
    • 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
    • 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
    • B01D71/58—Other polymers having nitrogen in the main chain, with or without oxygen or carbon only
    • B01D71/60—Polyamines
    • 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
    • B01D71/76—Macromolecular material not specifically provided for in a single one of groups B01D71/08 - B01D71/74
    • 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
    • B01D2325/00—Details relating to properties of membranes
    • B01D2325/38—Hydrophobic membranes

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Abstract

The invention discloses a Janus film and a preparation method thereof, wherein the Janus film comprises a hydrophobic base layer, a hydrophobic doping layer and a hydrophilic layer which are sequentially laminated; the hydrophobic substrate layer is made of hydrophobic organic polymer, and the hydrophobic doping layer is made of materials with the mass ratio of 1.5-6: 10 and the hydrophobic organic matter, wherein the material of the hydrophilic layer is hydrophilic organic polymer. In the Janus membrane, the hydrophilic layer is made of hydrophilic organic polymers, the hydrophobic doping layer improves the interface compatibility of the hydrophobic substrate layer and the hydrophilic layer, so that the Janus membrane shows good integrity, the Janus membrane is high in use stability in the MD process, long in service life and capable of being improved in large-scale applicability.

Description

Janus film and preparation method thereof
Technical Field
The invention relates to the field of oil-water separation, in particular to a Janus film and a preparation method thereof.
Background
In recent years, membrane Distillation (MD) has received much attention in the direction of wastewater reclamation to solve the problem of water resource shortage because of its potential for treating high-salt and complex high-salt oily wastewater. Compared with the currently widely used membrane separation technology based on pressurization (such as Reverse Osmosis (RO)), the MD technology for driving the separation process by the steam pressure difference between two sides of the membrane not only breaks the limitation of salt concentration in the treatment process of water with high salt content, but also can reduce the energy consumption of the separation process by using cheap energy sources such as waste heat, solar energy, geothermal energy and the like as heat sources [1]. To date, MD technology still faces two key challenges in large-scale application, namely membrane wetting and fouling phenomena, and especially the wet and anti-fouling capacity of MD separation membranes is greatly challenged when treating complex high-salt oily wastewater generated by the oil, gas or textile industries.
The surface of the MD separation membrane is wetted and the separation performance is compromised when the feed liquid "drag" across the barrier and reaches the permeate side, overcoming the membrane pores [2]. In general, in the presence of a surfactant, an oil pollutant, humic acid, and the like, the surface tension of feed wastewater is relatively low, and the wetting process of the film in the MD process is accelerated. In order to overcome the problem of membrane wetting failure, researchers have improved the hydrophobic properties of general membrane surfaces to superhydrophobic levels (water contact angles > 150 °) by using low surface energy materials and methods for manipulating the microstructure of the material surface. Although the moisture resistance of the resulting superhydrophobic films is significantly improved, the oleophilic nature of the films reduces their resistance to scaling due to "hydrophobic-hydrophobic" intermolecular interactions between the films and organic contaminants (e.g., oils). In these cases, the oil stain will destroy the original superhydrophobicity of the membrane and cause severe fouling problems, affecting membrane failure during MD.
Membrane Distillation (MD) has received increasing attention in the treatment of high salt oily wastewater. The MD process not only has a significant advantage in saving energy, but also can be driven without the limitation of brine concentration compared with the conventional membrane technology based on pressure difference as separation driving force [3]. In order to overcome the problems of membrane wetting, scaling and the like in the wastewater purification process, cheng et al [4] propose a Janus membrane with asymmetric wettability, and have great potential in solving the problems of membrane wetting and membrane pollution. The Janus membrane is formed by coupling the hydrophilic layer and the hydrophobic layer, and the good anti-wet and anti-fouling effects are achieved through the synergistic effect of the two layers.
The micro/nano structure, roughness and material intrinsic surface energy of the Janus film surface are the key factors for determining the moisture resistance of the surface. Based on this principle, methods for preparing Janus films by electrostatic spray deposition, vacuum filtration, co-casting phase transition coating, layer-by-layer assembly, plasma treatment, etc. have been widely developed. Electrostatic spraying/painting has been given extremely high expectations in terms of controllability of the microstructure and properties (e.g., thickness, porosity and hydrophobicity) of Janus films and industrial producibility. However, the current Janus membranes constructed based on any method have the problems of different degrees of material interface compatibility, so that the stability of the Janus membranes in the MD separation process is poor, the service life is short, and the scale applicability is low.
Reference documents:
[1]M.Elimelech,W.A.Phillip,The future of seawater desalination:energy,technology,and the environment,Science 333,(2011)712-717,https://doi.org/10.1126/science.1200488.
[2]T.Horseman,Y.Yin,K.S.Christie,Z.Wang,T.Tong,S.Lin,Wetting,scaling,and fouling in membrane distillation:state-of-the-art insights on fundamental mechanisms and mitigation strategies,ACS ES&T Eng.1(2021),117-140,https://doi.org/10.1021/acsestengg.0c00025.
[3]S.Lin,Energy efficiency of desalination:fundamental insights from intuitive interpretation,Environ.Sci.Technol.54,(2020),76-84,https://doi.org/10.1021/acs.est.9b04788.
[4]D.Y.Cheng,S.J.Wiersma,Composite Membrane for a Membrane Distillation System Google Patents,1982.
disclosure of Invention
Based on this, there is a need for a Janus film and a method for preparing the same that can solve the above problems.
A Janus film comprises a hydrophobic substrate layer, a hydrophobic doping layer and a hydrophilic layer which are sequentially stacked;
the hydrophobic substrate layer is made of hydrophobic organic polymer, and the hydrophobic doping layer is made of materials with the mass ratio of (1.5-6): 10 and the hydrophobic organic matter, wherein the material of the hydrophilic layer is hydrophilic organic polymer.
In one embodiment, the particle size of the polyhedral silsesquioxane nanoparticles is 1nm to 3nm.
In one embodiment, the surface of the hydrophobic doped layer far away from the hydrophobic substrate layer is a bead-shaped multi-dimensional rough surface, and the surface of the hydrophilic layer far away from the hydrophobic doped layer is provided with a bead-shaped nano-filament structure.
In one embodiment, the thickness of the hydrophobic substrate layer is 50 μm to 150 μm, the thickness of the hydrophobic doped layer is 3 μm to 9 μm, and the thickness of the hydrophilic layer is 10 μm to 20 μm.
In one embodiment, the hydrophobic organic polymer is selected from at least one of PVDF, PP and PTFE, and the hydrophilic organic polymer is selected from at least one of PDA, m-PES, CA, PAN and PA.
The preparation method of the Janus film comprises the following steps:
providing organic dispersion liquid of polyhedral oligomeric silsesquioxane nanoparticles and hydrophobic organic matter, wherein the mass concentration of the polyhedral oligomeric silsesquioxane nanoparticles is 0.5-3%, the mass concentration of the hydrophobic organic matter is 1-5%, and the mass ratio of the polyhedral oligomeric silsesquioxane nanoparticles to the hydrophobic organic matter is 1.5-6: 10;
preparing a hydrophobic doping layer on a hydrophobic substrate layer by using the organic dispersion liquid through first electrostatic spraying, wherein the hydrophobic substrate layer is made of hydrophobic organic polymers, drying is carried out to obtain a semi-finished product, the voltage of the first electrostatic spraying is 15 kV-30 kV, the feeding speed of the first electrostatic spraying is 0.5 mL/h-2 mL/h, and the distance between a spinning tower and a collector of the first electrostatic spraying is 6 cm-12 cm;
and (2) carrying out secondary electrostatic spraying on the hydrophobic doping layer by using an organic solution of a hydrophilic organic polymer to prepare a hydrophilic layer, and drying again to obtain the needed Janus film, wherein the mass concentration of the organic solution of the hydrophilic organic polymer is 1.5-5%, the voltage of the secondary electrostatic spraying is 12 kV-24 kV, the feeding speed of the secondary electrostatic spraying is 0.25 mL/h-1 mL/h, and the distance between a spinning tower and a collector of the secondary electrostatic spraying is 8 cm-15 cm.
In one embodiment, the solvent of the organic dispersion is DMF, DMAc, or DMSO, and the solvent of the organic solution of the hydrophilic organic polymer is DMF, DMAc, or DMSO.
In one embodiment, the voltage of the first electrostatic spraying is 25kV, the feeding speed of the first electrostatic spraying is 1mL/h, and the distance between the spinning tower and the collector of the first electrostatic spraying is 8cm.
In one embodiment, the voltage of the second electrostatic spraying is 18kV, the feeding speed of the second electrostatic spraying is 0.5mL/h, and the distance between the spinning tower and the collector of the second electrostatic spraying is 10cm.
In one embodiment, the organic dispersion is prepared by:
and ultrasonically dispersing the polyhedral silsesquioxane nanoparticles into an organic solvent, then adding the granular hydrophobic organic matter again, and stirring at 50-70 ℃ for 16-36 h to obtain the organic dispersion liquid.
In the Janus film, the hydrophobic substrate layer is made of hydrophobic organic polymer, and the hydrophobic doped layer is made of materials with the mass ratio of 1.5-6: 10, the hydrophilic layer is made of a hydrophilic organic polymer, and the hydrophobic doping layer improves the interface compatibility of the hydrophobic substrate layer and the hydrophilic layer, so that the Janus membrane shows good integrity, has high use stability in the MD process, long service life and improved large-scale applicability.
The polyhedral oligomeric silsesquioxane is combined with the properties of inorganic and organic materials and used as a filler of the hydrophobic doped layer, can be effectively dispersed in a spraying solution, can effectively adjust the surface micro-morphology of the hydrophobic doped layer, and is the key for realizing the super-hydrophobicity of the Janus film.
In combination with specific examples, when the soybean oil emulsion in brine is used as a feeding liquid in an MD process, the Janus membrane provided by the invention shows stable and excellent desalting performance and has high water flux, and the Janus membrane with the same performance is prepared by a repeated test mode, and has the potential of industrial production.
Preferably, one surface of the hydrophobic doping layer, which is far away from the hydrophobic substrate layer, is a beaded multidimensional rough surface, and one surface of the hydrophilic layer, which is far away from the hydrophobic doping layer, is provided with a bead-shaped nano-filament structure, so that the prepared Janus membrane is high in water flux, and has stable surface hydrophilicity and underwater super lipophobicity.
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 some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
Wherein:
fig. 1 is a schematic structural diagram of a Janus membrane according to an embodiment.
Fig. 2 is a flow chart of a method of making a Janus membrane as shown in fig. 1.
Fig. 3 is SEM images of the semi-finished product obtained in example 1 and the Janus membrane obtained in example 1, wherein a and b are the surface topography and cross-sectional topography of the semi-finished product obtained in example 1, respectively, and d and e are the surface topography and cross-sectional topography of the Janus membrane obtained in example 1, respectively.
FIG. 4 is a graph of normalized water flux and rejection results for the commercial PVDF membrane of example 1.
FIG. 5 is a graph of normalized water flux and salt rejection results for the intermediate product of example 1.
Fig. 6 is a graph of normalized water flux and salt rejection results for the Janus membrane of example 1.
Fig. 7 is a graph of the results of testing the commercial PVDF membrane of example 1, the semi-finished product of example 1, and the Janus membrane of example 1 for treatment of complex oily high brine.
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.
The Janus membrane of one embodiment shown in fig. 1 includes a hydrophobic base layer 10, a hydrophobic doped layer 20, and a hydrophilic layer 30, which are sequentially stacked.
The hydrophobic substrate layer 10 is made of hydrophobic organic polymer, and the hydrophobic doping layer 20 is made of materials with the mass ratio of (1.5-6): 10 and the hydrophilic layer 30 is made of hydrophilic organic polymer.
In the Janus film, the hydrophobic base layer 10 is made of hydrophobic organic polymer, and the hydrophobic doping layer 20 is made of materials with the mass ratio of (1.5-6): 10, the hydrophilic layer 30 is made of hydrophilic organic polymer, and the hydrophobic doping layer 20 improves the interface compatibility of the hydrophobic substrate layer 10 and the hydrophilic layer 30, so that the Janus membrane shows good integrity, has high use stability in the MD process, has long service life and can be applied in a large scale.
The polyhedral oligomeric silsesquioxane is used as a filler of the hydrophobic doping layer 20 by combining the properties of inorganic and organic materials, can be effectively dispersed in a spraying solution, can effectively adjust the surface micro-morphology of the hydrophobic doping layer 20, and is the key for realizing the superhydrophobicity of the Janus film.
In combination with specific examples, when the method is applied to an MD process, the Janus film provided by the invention is stable and excellent in desalting performance and has high water flux, and the Janus film with the same performance is prepared by a repeated test mode, and has the potential of industrial production.
In the present embodiment, the particle diameter of the polyhedral silsesquioxane nanoparticles is preferably 1nm to 3nm.
The polyhedral oligomeric silsesquioxane nano-particle can be prepared by self or directly purchased.
In this embodiment, one surface of the hydrophobic doped layer 20 away from the hydrophobic substrate layer 10 is a beaded multidimensional rough surface, and one surface of the hydrophilic layer 30 away from the hydrophobic doped layer 20 has a bead-like nanowire structure.
One surface of the hydrophobic doping layer 20, which is far away from the hydrophobic substrate layer 10, is a beaded multidimensional rough surface, and one surface of the hydrophilic layer 30, which is far away from the hydrophobic doping layer 20, is provided with a beaded nano-wire structure, so that the prepared Janus membrane has high water flux, and has stable surface hydrophilicity and underwater super-lipophobicity.
Generally, the hydrophobic doped layer 20 can be formed into a bead-shaped multi-dimensional rough surface on the side away from the hydrophobic substrate layer 10 by an electrostatic spraying method, and the hydrophilic layer 30 has a bead-shaped nanowire structure on the side away from the hydrophobic doped layer 20.
Preferably, in the present embodiment, the thickness of the hydrophobic base layer 10 is 50 μm to 150 μm, the thickness of the hydrophobic doping layer 20 is 3 μm to 9 μm, and the thickness of the hydrophilic layer 30 is 10 μm to 20 μm.
Preferably, in the present embodiment, the hydrophobic organic polymer is selected from at least one of PVDF (polyvinylidene fluoride), PP (polypropylene), and PTFE (polytetrafluoroethylene), and the hydrophilic organic polymer is selected from at least one of Polydopamine (PDA), modified polyethersulfone (m-PES), cellulose Acetate (CA), polyacrylonitrile (PAN), and Polyamide (PA).
The invention also discloses a preparation method of the Janus membrane, which comprises the following steps:
s10, providing an organic dispersion liquid of polyhedral oligomeric silsesquioxane nanoparticles and hydrophobic organic matter.
In general, in the organic dispersion, the mass concentration of the polyhedral silsesquioxane nanoparticles is 0.5 to 3%, the mass concentration of the hydrophobic organic substance is 1 to 5%, and the mass ratio of the polyhedral silsesquioxane nanoparticles to the hydrophobic organic substance is 1.5 to 6:10.
preferably, the organic dispersion is prepared by: ultrasonically dispersing polyhedral silsesquioxane nanoparticles into an organic solvent, then adding granular hydrophobic organic matters again, and stirring at 50-70 ℃ for 16-36 h to obtain an organic dispersion liquid.
Preferably, the solvent of the organic dispersion is DMF, DMAc or DMSO.
And S20, performing first electrostatic spraying on the hydrophobic base layer 10 by using the organic dispersion liquid obtained in the S10 to prepare a hydrophobic doping layer 20, wherein the hydrophobic base layer 10 is made of a hydrophobic organic polymer, and drying to obtain a semi-finished product.
Generally, the voltage of the first electrostatic spraying is 15kV to 30kV, the feeding speed of the first electrostatic spraying is 0.5mL/h to 2mL/h, and the distance between the spinning tower and the collector of the first electrostatic spraying is 6cm to 12cm.
Preferably, the voltage of the first electrostatic spraying is 25kV, the feeding speed of the first electrostatic spraying is 1mL/h, and the distance between a spinning tower and a collector of the first electrostatic spraying is 8cm.
In this embodiment, the operation of drying to obtain the semi-finished product may be: drying in an oven at 80 ℃.
In this embodiment, the first electrostatic spraying can be carried out using an ET-2535 device of Yongkangle, beijing.
And S30, carrying out secondary electrostatic spraying on the hydrophobic doping layer 20 obtained in the S20 by using an organic solution of a hydrophilic organic polymer to prepare a hydrophilic layer 30, and drying again to obtain the needed Janus film.
In the organic solution of the hydrophilic organic polymer, the mass concentration of the organic solution of the hydrophilic organic polymer is 1.5-5%.
Generally, the voltage of the second electrostatic spraying is 12kV to 24kV, the feeding speed of the second electrostatic spraying is 0.25mL/h to 1mL/h, and the distance between the spinning tower and the collector of the second electrostatic spraying is 8cm to 15cm.
Preferably, the voltage of the second electrostatic spraying is 18kV, the feeding speed of the second electrostatic spraying is 0.5mL/h, and the distance between the spinning tower and the collector of the second electrostatic spraying is 10cm.
Preferably, the solvent of the organic solution of the hydrophilic organic polymer is DMF, DMSO or DMAc.
In this embodiment, the second electrostatic spraying can be performed using an ET-2535 device of Yongkangle, beijing.
The following are specific examples.
In specific examples, the polyhedral silsesquioxane nanoparticles have a particle size of 1nm to 3nm and are available from Zhengzhou alpha corporation (A256791 CAS: 5256-79-1); commercial PVDF membrane is a Commercial PVDF membrane (HVHP 14250) having a thickness of 125 μm; electrostatic spraying was accomplished by means of an ET-2535 device in the peking yongkle industry.
Example 1
And dispersing the mixed POSS NPs into a DMF solvent, and carrying out ultrasonic treatment for 10 minutes to prepare POSS dispersion liquid. Then, an appropriate amount of PVDF particles are added into the solution, and then the solution is stirred at 60 ℃ for 24 hours to form a uniformly mixed POSS @ PVDF electrospray solution, wherein the mass concentration of POSS is 0.9wt%, and the mass concentration of PVDF is 3wt%.
And (3) depositing the POSS @ PVDF electric spraying solution prepared by the method on a commercial PVDF membrane by using an ET-2535 device to prepare the POSS @ PVDF membrane with super hydrophobicity, so as to obtain a semi-finished product. The electrospray condition was 25kV voltage, 1.0 mL. H-1The feed rate of (2) and the distance between the spinning tower and the collector were 8cm. Subsequently, the semi-finished product obtained by the preparation was completely dried in an oven at 80 ℃.
PAN polymer was dissolved in DMF solvent to obtain a PAN electrospray solution with a mass concentration of 3wt%. Then prepared using the same electrospray equipment and procedure, with specific parameters of 18kV voltage, 10cm tip-to-collector distance and 0.5 mL-h1PAN spray solution feed rate of (d). Finally, the resulting membrane was dried in an oven at 60 ℃ overnight, and residual DMF was removed to produce PAN/poss @ pvdf Janus membrane.
Example 2
And dispersing the mixed POSS NPs into a DMF solvent, and carrying out ultrasonic treatment for 10 minutes to prepare POSS dispersion liquid. Then, an appropriate amount of PVDF particles are added into the solution, and then the mixture is stirred at 60 ℃ for 24 hours to form a uniformly mixed POSS @ PVDF electronic spraying solution, wherein the mass concentration of POSS is 0.5wt%, and the mass concentration of PVDF is 1.5wt%.
And (3) depositing the POSS @ PVDF electric spraying solution prepared by the method on a commercial PVDF membrane by using an ET-2535 device to prepare the POSS @ PVDF membrane with super hydrophobicity, so as to obtain a semi-finished product. The electrospray condition is 15kV voltage, 2 mL.h-1The feed rate of (2) and the distance between the spinning tower and the collector were 6cm. Subsequently, the semi-finished product obtained by the preparation is completely dried in an oven at 80 ℃.
PAN polymer was dissolved in DMF solvent to obtain PAN electrode with a mass concentration of 1.5wt%And spraying the solution. Then prepared using the same electrospray equipment and procedure, with specific parameters of 24kV voltage, 8cm tip-to-collector distance, and 0.25 mL-h1PAN spray solution feed rate of (d). Finally, the membrane obtained was dried overnight in an oven at 60 ℃ and the residual DMF was removed to prepare a PAN/POSS @ PVDF Janus membrane.
Example 3
And dispersing the mixed POSS NPs into a DMF solvent, and carrying out ultrasonic treatment for 10 minutes to prepare POSS dispersion liquid. Then, an appropriate amount of PVDF particles are added into the solution, and then the solution is stirred at 60 ℃ for 24 hours to form a uniformly mixed POSS @ PVDF electrospray solution, wherein the mass concentration of POSS is 3wt%, and the mass concentration of PVDF is 5wt%.
And (3) depositing the POSS @ PVDF prepared by the method on a commercial PVDF film by using an ET-2535 device to prepare the POSS @ PVDF film with super hydrophobicity, so as to obtain a semi-finished product. The electrospray condition was 30kV voltage, 0.5 mL. H-1The feed rate of (2) and the distance between the spinning tower and the collector were 12cm. Subsequently, the semi-finished product obtained by the preparation is completely dried in an oven at 80 ℃.
PAN polymer was dissolved in DMF solvent to obtain PAN electrospray solution with mass concentration of 5wt%. Then prepared using the same electrospray equipment and procedure, with specific parameters of 12kV voltage, 15cm tip-to-collector distance and 1 mL-h1PAN spray solution feed rate of (d). Finally, the resulting membrane was dried in an oven at 60 ℃ overnight, and residual DMF was removed to produce PAN/poss @ pvdf Janus membrane.
Test example
1. Micro-topography characterization of films
Surface morphology and cross-sectional morphology observations were made of the semi-finished product obtained in example 1 and the PAN/POSS @ PVDF Janus film obtained in example 1, yielding FIG. 3.
Compared with a porous commercial PVDF membrane, the surface of the POSS @ PVDF membrane modified by electrospray coating has a multi-scale rough surface, and as shown in FIG. 3a, the rough structure of the surface is mainly formed by winding POSS @ PVDF bead-like micro units.
According to the Cassie Baxter model, multi-scale surface roughness can greatly increase the Water Contact Angle (WCA) of the membrane, thereby possibly imparting superhydrophobicity to the membrane. The thickness of the prepared POSS @ PVDF layer is about 5 μm, and in a cross-sectional view, some active layers can clearly penetrate through a substrate, which means that the coating film has good integral performance and plays a key role in improving the use stability of the film (figure 3 b).
As shown in FIG. 3d, the surface of the hydrophilic PAN layer of the prepared PAN/POSS @ PVDF Janus membrane is composed of the nano-fibers wound with bead-shaped structures, and shows rough micro/nano surface structures. In addition, the PAN modifying layer had good adhesion to the poss @ pvdf hydrophobic layer, as shown in the cross-sectional image (fig. 3 e), with a thickness of about 15 μm. The excellent interface compatibility is the basis that the PAN/POSS @ PVDF Janus film prepared by the invention can be stably used in the MD process.
2. Complex DCMD Performance
Membrane wettability is a key requirement for maintaining stable and sustainable desalination performance.
The commercial PVDF membrane of example 1 (saline feed monitoring with SDS), the semi-finished product of example 1 (superhydrophobic POSS @ PVDF coated membrane) and the Janus membrane of example 1 (PAN/POSS @ PVDF) were tested for their anti-wetting properties, respectively, and the normalized water flux and salt rejection results are shown in FIGS. 4-6.
Therein, a simulated wastewater test solution (3.5% NaCl solution) was prepared by adding SDS surfactant. The initial flux of the commercial PVDF membrane of example 1 (SDS-containing brine feed monitoring), the semi-finished product of example 1 (superhydrophobic poss @ PVDF coated membrane) and the Janus membrane of example 1 (PAN/poss @ PVDF) were 27.3LMH, 23.6LMH and 22.8LMH, respectively.
Comparing fig. 4, fig. 5 and fig. 6, the superhydrophobic membrane and the Janus membrane maintained stable water flux and high salt rejection throughout the run at SDS concentrations as high as 0.3 mM. Both the semi-finished product of example 1 (superhydrophobic poss @ PVDF coated film) and the Janus film of example 1 (PAN/poss @ PVDF) had the same excellent moisture resistance compared to commercial PVDF films.
In addition, the semi-finished product of example 1 (superhydrophobic poss @ pvdf coated membrane) and Janus membrane of example 1 (PAN/poss @ pvdf) have near moisture resistance, indicating that PAN hydrophilic layers modified by appropriate formulations and processes do not sacrifice the superhydrophobicity of the underlying poss @ pvdf membrane.
3. DCMD performance of complex oil-water mixed system
To further evaluate the availability of Janus membranes in processing complex oily high-salt water, the separation performance of Janus membranes was tested using 0.5g/L soybean oil, 0.3mM SDS, and 3.5wt% nacl composition of stable oil-in-water emulsions as DCMD feed solutions to obtain figure 7.
As in the previous section, the same concentration of SDS (0.3 mM) was maintained to avoid confounding the different failure mechanisms so that their anti-wetting and anti-fouling properties could be better analyzed. At the same time, the performance of the commercial PVDF film and the poss @ PVDF coating super hydrophobic film were also compared.
As shown in fig. 7, commercial PVDF membranes showed the most severe flux and salt rejection, the fastest rate, and a performance decay after 20 minutes of operation, indicating fouling and wetting problems with the membrane. For superhydrophobic membranes, the water flux drops relatively slowly throughout the 90 minute MD test, but eventually drops to around 30% of the initial water flux. At the same time, the salt rejection remained constant, with high values >99.99%, indicating that the layered poss @ pvdf coating can improve the resistance of the membrane to wetting, but still be poor in fouling resistance. Compared with the original PVDF film, the POSS @ PVDF super-hydrophobic film still shows better antifouling performance due to the fact that the contact area between oil and the film and the layered surface structure is smaller.
As shown in FIG. 7, the PAN/POSS @ PVDF Janus membrane prepared in example 1 has excellent and stable desalination rate (> 99.99%), and the water flux fluctuates only in a small range in the whole DCMD operation process, so that the PAN/POSS @ PVDF Janus membrane prepared in example 1 can be stably used in the MD process and has the capability of stably separating complex oil-containing high-salt wastewater.
The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is specific and detailed, but not to be construed as limiting the scope of the claims. It should be noted that various changes and modifications can be made by those skilled in the art without departing from the spirit of the invention, and these changes and modifications are all within the scope of the invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (10)

1. A Janus film is characterized by comprising a hydrophobic substrate layer, a hydrophobic doping layer and a hydrophilic layer which are sequentially stacked;
the hydrophobic substrate layer is made of hydrophobic organic polymer, and the hydrophobic doping layer is made of materials with the mass ratio of (1.5-6): 10, the material of the hydrophilic layer is hydrophilic organic polymer.
2. The Janus film as claimed in claim 1, wherein the polyhedral silsesquioxane nanoparticles have a particle size of 1nm to 3nm.
3. The Janus membrane of claim 1, wherein one side of the hydrophobic doped layer away from the hydrophobic substrate layer is a beaded multi-dimensional rough surface, and one side of the hydrophilic layer away from the hydrophobic doped layer has a bead-like nanowire structure.
4. The Janus membrane of claim 1, wherein the hydrophobic base layer has a thickness of 50 to 150 μ ι η, the hydrophobic doped layer has a thickness of 3 to 9 μ ι η, and the hydrophilic layer has a thickness of 10 to 20 μ ι η.
5. The Janus membrane of claim 4 wherein the hydrophobic organic polymer is selected from at least one of PVDF, PP and PTFE, and the hydrophilic organic polymer is selected from at least one of PDA, m-PES, CA, PAN and PA.
6. A method of making a Janus film as defined in any one of claims 1-5, comprising the steps of:
providing organic dispersion liquid of polyhedral oligomeric silsesquioxane nanoparticles and hydrophobic organic matter, wherein the mass concentration of the polyhedral oligomeric silsesquioxane nanoparticles is 0.5-3%, the mass concentration of the hydrophobic organic matter is 1-5%, and the mass ratio of the polyhedral oligomeric silsesquioxane nanoparticles to the hydrophobic organic matter is 1.5-6: 10;
preparing a hydrophobic doping layer on a hydrophobic substrate layer by using the organic dispersion liquid through first electrostatic spraying, wherein the hydrophobic substrate layer is made of hydrophobic organic polymers, drying is carried out to obtain a semi-finished product, the voltage of the first electrostatic spraying is 15 kV-30 kV, the feeding speed of the first electrostatic spraying is 0.5 mL/h-2 mL/h, and the distance between a spinning tower and a collector of the first electrostatic spraying is 6 cm-12 cm;
and (2) carrying out secondary electrostatic spraying on the hydrophobic doping layer by using an organic solution of a hydrophilic organic polymer to prepare a hydrophilic layer, and drying again to obtain the needed Janus film, wherein the mass concentration of the organic solution of the hydrophilic organic polymer is 1.5-5%, the voltage of the secondary electrostatic spraying is 12 kV-24 kV, the feeding speed of the secondary electrostatic spraying is 0.25 mL/h-1 mL/h, and the distance between a spinning tower and a collector of the secondary electrostatic spraying is 8 cm-15 cm.
7. The method of claim 6, wherein the solvent of the organic dispersion is DMF, DMAc, or DMSO, and the solvent of the organic solution of the hydrophilic organic polymer is DMF, DMAc, or DMSO.
8. The method of claim 6, wherein the voltage of the first electrostatic spraying is 25kV, the feed rate of the first electrostatic spraying is 1mL/h, and the distance between the spinning tower and the collector of the first electrostatic spraying is 8cm.
9. The method of making a Janus membrane as in claim 6, wherein the voltage of the second electrostatic spraying is 18kV, the feed rate of the second electrostatic spraying is 0.5mL/h, and the distance between the spinning tower and the collector of the second electrostatic spraying is 10cm.
10. The method of making a Janus membrane according to claim 6, wherein the organic dispersion is prepared by:
ultrasonically dispersing the polyhedral silsesquioxane nanoparticles into an organic solvent, then adding the granular hydrophobic organic matter again, and stirring at 50-70 ℃ for 16-36 h to obtain the organic dispersion liquid.
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Citations (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103087088A (en) * 2011-10-28 2013-05-08 江南大学 Preparation and applications of novel alkyl cage silsesquioxane nanometer hybrid
US20140326657A1 (en) * 2013-05-06 2014-11-06 Samsung Electronics Co., Ltd. Semi-permeable film, membrane including the semi-permeable film, and method of manufacturing the semi-permeable film
US20140326658A1 (en) * 2011-11-17 2014-11-06 Ngee Ann Polytechnic Triple Layer Hydrophobic-Hydrophilic Membrane for Membrane Distillation Applications
CN104606924A (en) * 2015-01-27 2015-05-13 厦门出入境检验检疫局检验检疫技术中心 Chitosan bonded organic-silica gel hybridization monolithic column and preparation method thereof
CN106215462A (en) * 2016-08-29 2016-12-14 华南理工大学 Super-hydrophobic/super-oleophilic stainless (steel) wire based on POSS base hydridization acrylate coatings and preparation method and application
CN106669430A (en) * 2016-11-21 2017-05-17 重庆云天化瀚恩新材料开发有限公司 Nano-structured organic-inorganic hybrid molecule modified reverse osmosis membrane and preparation method thereof
CN107855007A (en) * 2017-07-13 2018-03-30 枫科(北京)膜技术有限公司 A kind of asymmetric forward osmosis membrane and preparation method thereof
CN108404685A (en) * 2018-04-14 2018-08-17 哈尔滨工业大学 A kind of high penetration, resistance to wetting, pollution-resistant membrane distillation distillation film preparation method
CN108654411A (en) * 2018-05-15 2018-10-16 苏州苏瑞膜纳米科技有限公司 The reverse osmosis composite membrane and preparation method thereof that polyhydroxy cage-type silsesquioxane is modified
US20180345227A1 (en) * 2017-06-01 2018-12-06 Vanderbilt University Composite membranes and methods of making and use thereof
US20200156006A1 (en) * 2018-11-16 2020-05-21 National Taiwan University Omniphobic Membranes and Application Thereof
CN112717717A (en) * 2020-12-11 2021-04-30 中化(宁波)润沃膜科技有限公司 Polysulfone-based membrane, reverse osmosis composite membrane containing same and preparation method
CN112774463A (en) * 2020-12-10 2021-05-11 南京工业大学 Graphene oxide separation membrane with stable structure and preparation method thereof
CN113122134A (en) * 2019-12-30 2021-07-16 郑州科斗科技有限公司 Nano fluorine-silicon hybrid stone cultural relic protection material and preparation method thereof
CN113304622A (en) * 2021-06-16 2021-08-27 中国科学院生态环境研究中心 POSS/PVDF composite membrane with hydrophobic surface, preparation method and application thereof
CN113564918A (en) * 2021-07-05 2021-10-29 东莞理工学院 Janus fabric with liquid drop one-way permeability and preparation method thereof
CN113750805A (en) * 2021-09-29 2021-12-07 南京理工大学 Preparation method of fiber distillation membrane for anti-scaling wrinkled membrane distillation
CN114011248A (en) * 2021-09-29 2022-02-08 广州先进技术研究所 Core liquid replaceable type thermally induced phase separation membrane preparation method
CN114085409A (en) * 2021-11-30 2022-02-25 中国科学院生态环境研究中心 Super-hydrophobic and super-oleophobic membrane and preparation method thereof
CN114618329A (en) * 2022-04-02 2022-06-14 天津工业大学 Membrane for three-dimensional super-hydrophobic membrane distillation and preparation method thereof

Patent Citations (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103087088A (en) * 2011-10-28 2013-05-08 江南大学 Preparation and applications of novel alkyl cage silsesquioxane nanometer hybrid
US20140326658A1 (en) * 2011-11-17 2014-11-06 Ngee Ann Polytechnic Triple Layer Hydrophobic-Hydrophilic Membrane for Membrane Distillation Applications
US20140326657A1 (en) * 2013-05-06 2014-11-06 Samsung Electronics Co., Ltd. Semi-permeable film, membrane including the semi-permeable film, and method of manufacturing the semi-permeable film
CN104606924A (en) * 2015-01-27 2015-05-13 厦门出入境检验检疫局检验检疫技术中心 Chitosan bonded organic-silica gel hybridization monolithic column and preparation method thereof
CN106215462A (en) * 2016-08-29 2016-12-14 华南理工大学 Super-hydrophobic/super-oleophilic stainless (steel) wire based on POSS base hydridization acrylate coatings and preparation method and application
CN106669430A (en) * 2016-11-21 2017-05-17 重庆云天化瀚恩新材料开发有限公司 Nano-structured organic-inorganic hybrid molecule modified reverse osmosis membrane and preparation method thereof
US20180345227A1 (en) * 2017-06-01 2018-12-06 Vanderbilt University Composite membranes and methods of making and use thereof
CN107855007A (en) * 2017-07-13 2018-03-30 枫科(北京)膜技术有限公司 A kind of asymmetric forward osmosis membrane and preparation method thereof
CN108404685A (en) * 2018-04-14 2018-08-17 哈尔滨工业大学 A kind of high penetration, resistance to wetting, pollution-resistant membrane distillation distillation film preparation method
CN108654411A (en) * 2018-05-15 2018-10-16 苏州苏瑞膜纳米科技有限公司 The reverse osmosis composite membrane and preparation method thereof that polyhydroxy cage-type silsesquioxane is modified
US20200156006A1 (en) * 2018-11-16 2020-05-21 National Taiwan University Omniphobic Membranes and Application Thereof
CN113122134A (en) * 2019-12-30 2021-07-16 郑州科斗科技有限公司 Nano fluorine-silicon hybrid stone cultural relic protection material and preparation method thereof
CN112774463A (en) * 2020-12-10 2021-05-11 南京工业大学 Graphene oxide separation membrane with stable structure and preparation method thereof
CN112717717A (en) * 2020-12-11 2021-04-30 中化(宁波)润沃膜科技有限公司 Polysulfone-based membrane, reverse osmosis composite membrane containing same and preparation method
CN113304622A (en) * 2021-06-16 2021-08-27 中国科学院生态环境研究中心 POSS/PVDF composite membrane with hydrophobic surface, preparation method and application thereof
CN113564918A (en) * 2021-07-05 2021-10-29 东莞理工学院 Janus fabric with liquid drop one-way permeability and preparation method thereof
CN113750805A (en) * 2021-09-29 2021-12-07 南京理工大学 Preparation method of fiber distillation membrane for anti-scaling wrinkled membrane distillation
CN114011248A (en) * 2021-09-29 2022-02-08 广州先进技术研究所 Core liquid replaceable type thermally induced phase separation membrane preparation method
CN114085409A (en) * 2021-11-30 2022-02-25 中国科学院生态环境研究中心 Super-hydrophobic and super-oleophobic membrane and preparation method thereof
CN114618329A (en) * 2022-04-02 2022-06-14 天津工业大学 Membrane for three-dimensional super-hydrophobic membrane distillation and preparation method thereof

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