CN115007219A - TiO 2 2 Forward-osmosis photocatalytic membrane modified by PTFE (polytetrafluoroethylene) supporting layer and preparation method thereof - Google Patents
TiO 2 2 Forward-osmosis photocatalytic membrane modified by PTFE (polytetrafluoroethylene) supporting layer and preparation method thereof Download PDFInfo
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- 229910010413 TiO 2 Inorganic materials 0.000 title claims abstract description 41
- 238000009292 forward osmosis Methods 0.000 title claims abstract description 35
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- QJZYHAIUNVAGQP-UHFFFAOYSA-N 3-nitrobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic acid Chemical compound C1C2C=CC1C(C(=O)O)C2(C(O)=O)[N+]([O-])=O QJZYHAIUNVAGQP-UHFFFAOYSA-N 0.000 description 2
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Images
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
- B01J31/26—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24
- B01J31/38—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24 of titanium, zirconium or hafnium
-
- B01J35/23—
-
- B01J35/39—
-
- B01J35/59—
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/30—Treatment of water, waste water, or sewage by irradiation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/72—Treatment of water, waste water, or sewage by oxidation
- C02F1/725—Treatment of water, waste water, or sewage by oxidation by catalytic oxidation
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/34—Organic compounds containing oxygen
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/38—Organic compounds containing nitrogen
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/40—Organic compounds containing sulfur
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2305/00—Use of specific compounds during water treatment
- C02F2305/10—Photocatalysts
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A20/00—Water conservation; Efficient water supply; Efficient water use
- Y02A20/124—Water desalination
- Y02A20/131—Reverse-osmosis
Abstract
The invention discloses a TiO 2 2 A PTFE supporting layer modified forward osmosis photocatalytic membrane and a preparation method thereof, belonging to the technical field of water treatment. The invention combines membrane filtration and photocatalytic degradation, and utilizes the membrane filtration process to enrich pollutants, thereby increasing the catalytic efficiency of the catalyst; meanwhile, the membrane surface pollutants are degraded by photocatalysis, so that the effect of relieving membrane pollution is achieved; the method comprises the following specific steps: using polymer film as carrier, TiO 2 PTFE isSurface modified material, drying TiO by oven 2 The PTFE dispersion is deposited on the surface of a support layer and is polymerized on the TiO by interfacial polymerization 2 Preparation of the back side of the PTFE modified layer to obtain TiO 2 -PTFE surface modified TFC-FO membranes. TiO prepared by the invention 2 The PTFE surface modified TFC-FO photocatalytic membrane shows high water flux and excellent anti-pollution performance under the membrane placement orientation of AL-DS; in the sewage treatment process, the modified membrane can efficiently relieve the deposition of pollutants on the surface of the membrane while keeping high water flux, and greatly improves the operation potential of the TFC-FO membrane in sewage treatment.
Description
Technical Field
The invention relates to a TiO compound 2 A PTFE supporting layer modified forward osmosis photocatalytic membrane and a preparation method thereof, belonging to the technical field of water treatment.
Background
The polyamide composite membrane (TFC membrane) mainly comprises a nonporous and highly crosslinked polyamide active layer (PA layer) and a porous supporting layer, and has the advantages of stable performance, low preparation cost, large-scale production and the like, so that the TFC membrane occupies a leading position in the production and application fields of Nanofiltration (NF), Reverse Osmosis (RO) and Forward Osmosis (FO) membranes. However, the development of TFC membranes is severely restricted by the problem of membrane fouling during long-term operation of FO.
Organic pollution is one of the important types of TFC membrane pollution, and after organic substances commonly existing in a water body, represented by Sodium Alginate (SA), Bovine Serum Albumin (BSA) and Humic Acid (HA), pollute the TFC membrane, the organic substances are deposited, adsorbed or accumulated on the surface or the internal structure of the membrane, so that a filter cake/gel layer is formed. Membrane fouling inevitably leads to unfavorable changes in membrane structure and significant deterioration of separation performance. In order to maintain a stable treatment effect, more frequent chemical cleaning must be performed. However, this not only increases the operating costs, but also greatly shortens the useful life of the membrane. Therefore, the key to ensuring the long-term stable operation of the TFC membrane is to improve the anti-pollution performance of the TFC membrane.
The FO technique is driven by the osmotic pressure difference between the Draw Solution (DS) and the Feed Solution (FS) on both sides of the membrane. As no external pressure is applied, FO has the advantages of low energy consumption and small membrane pollution tendency, and has remarkable advantages in the treatment of high-salt and high-pollution complex water bodies. Because of the asymmetric structure of the TFC membrane, FO has two membrane placement orientations during operation, namely an AL-FS mode with the PA layer facing the solution being treated and an AL-DS mode with the PA layer facing the draw solution. The initial water flux of the AL-FS mode is low, but the pollution resistance is strong; whereas the AL-DS mode has a high initial water flux but is heavily contaminated. In the face of complex water bodies, FO usually runs in an AL-FS mode, but the low efficiency of system operation and the easy pollution characteristic of a membrane seriously restrict the wide application of FO. The existing modification method generally utilizes a surface modification or functional substance doping method to regulate the property of the PA layer, so that pollutants in water are less adhered to the surface of the PA layer. However, as the contaminants are continually concentrated, high concentrations of contaminants also exacerbate the membrane fouling tendency.
Disclosure of Invention
[ problem ] to
The existing modification method cannot well solve the problems of low efficiency and high cost caused by the easy pollution characteristic of the TFC-FO membrane.
[ solution ]
In order to solve the problems, the invention combines membrane filtration and photocatalytic degradation, and utilizes the membrane filtration process to enrich pollutants, thereby increasing the catalytic efficiency of the catalyst; meanwhile, the membrane surface pollutants are degraded by photocatalysis, and the effect of relieving membrane pollution is achieved. The method comprises the following specific steps: using polymer film as carrier, TiO 2 PTFE is used as a modified material, and TiO is dried by adopting an oven 2 The PTFE dispersion is deposited on a support layer and is polymerized at the interface on the TiO 2 Preparation of the back side of the PTFE modified layer to obtain TiO 2 -a PTFE support layer modified TFC-FO membrane. The TFC-FO membrane prepared by the method has excellent anti-pollution performance and high water flux, and can effectively relieve the deposition of pollutants on the surface of the membrane in a sewage treatment process, so that the stable operation of the high water flux is kept, and the operation potential of the TFC-FO membrane in sewage treatment is greatly improved.
The first purpose of the invention is to provide a method for preparing TiO 2 -a method for forward osmosis photocatalytic membranes modified with a PTFE support layer, comprising the steps of:
(1)TiO 2 preparation of PTFE dispersion:
adding TiO into the diluted PTFE emulsion 2 Mixing the nano particles evenly by ultrasonic to obtain TiO 2 -a PTFE dispersion;
(2)TiO 2 preparation of the PTFE modified layer:
will go to stepTiO of step (1) 2 Depositing the PTFE dispersion on a polyether sulfone support layer by heating in an oven to obtain TiO 2 -a PTFE modified layer;
(3) preparation of TiO 2 -PTFE support layer modified forward osmosis photocatalytic membrane:
mixing the TiO obtained in the step (2) 2 Fixing the PTFE surface modification layer downwards, pouring a m-phenylenediamine solution on the surface of the membrane, and removing redundant m-phenylenediamine after infiltration; then pouring the trimesoyl chloride solution on the surface of the membrane for reaction, draining the membrane, then carrying out thermal crosslinking reaction in a hot water bath, and obtaining the TiO after the reaction is finished 2 -a PTFE support layer modified forward osmosis photocatalytic membrane.
In one embodiment of the present invention, the PTFE emulsion of step (1) has a weight percent of PTFE of 60%; the weight percentage of PTFE in the diluent is 0.23 percent; the solvent adopted by the diluent is water, and the proportion of the PTFE emulsion to the water is 0.38 g: 99.62 mL.
In one embodiment of the present invention, the PTFE emulsion of step (1) and TiO 2 The mass ratio of the nano particles is 0.38: 5.45.
in one embodiment of the present invention, the TiO described in step (1) 2 The particle size of the nano-particles is 3 nm-5 nm.
In one embodiment of the invention, the ultrasound in step (1) is performed for 10min at a power of 50-150W.
In one embodiment of the present invention, the deposition in step (2) is heated in an oven at 60 ℃ for 25 min.
In one embodiment of the present invention, the TiO described in the step (2) 2 The amount of the PTFE dispersion is 0.1 to 0.2mL/cm 2 。
In one embodiment of the present invention, the fixing in step (3) is to use a polytetrafluoroethylene plate frame, a rubber ring, a glass plate and a metal clip to fix the TiO of step (2) 2 The PTFE modified layer is fixed downwards.
In one embodiment of the invention, the m-phenylenediamine solution in the step (3) has a mass fraction of 2-4%, a soaking time of 1-10 min, and a soaking temperature of 15-25 ℃.
In one embodiment of the invention, the mass fraction of the trimesoyl chloride solution in the step (3) is 0.1-0.2%, the reaction is carried out for 1-10 min, and the reaction temperature is 15-25 ℃.
In one embodiment of the present invention, the amount of the m-phenylenediamine solution used in the step (3) is 0.6 to 0.7mL/cm 2 (ii) a The dosage of the trimesoyl chloride solution is 0.7-0.8 mL/cm 2 。
In one embodiment of the present invention, the thermal crosslinking reaction in step (3) is a thermal crosslinking reaction in a hot water bath at 80-100 ℃ for 2-5 min.
The second object of the present invention is TiO prepared by the method of the present invention 2 -a PTFE support layer modified forward osmosis photocatalytic membrane.
A third object of the present invention is a water treatment apparatus or plant containing the TiO of the present invention 2 -a PTFE support layer modified forward osmosis photocatalytic membrane.
The fourth object of the present invention is the TiO according to the invention 2 Use of a PTFE support layer modified forward osmosis photocatalytic membrane for water treatment.
[ advantageous effects ]
(1) The invention prepares TiO 2 When the-PTFE supporting layer is modified to be a forward osmosis photocatalytic film, TiO is dried by a simple oven drying method 2 PTFE is rapidly loaded onto the porous support layer of the TFC-FO membrane, resulting in a stable membrane structure. And the Al-DS is placed in the direction, the excellent permeability and anti-pollution performance are shown.
(2) TiO prepared by the invention 2 The forward osmosis photocatalytic membrane modified by the PTFE support layer reveals a mechanism for inhibiting the formation of membrane pollution by photocatalytic degradation of organic matters, namely, a photocatalytic material loaded on the surface of the forward osmosis membrane can generate strong oxidation species under illumination so as to oxidize pollutants on the surface of the membrane into small molecular organic matters, carbon dioxide and water.
(3) In the invention, TiO is mixed with 2 The forward osmosis photocatalytic membrane modified by the PTFE support layer is applied to the field of sewage treatment, and the influence of photocatalytic degradation of organic matters on membrane pollution is provedOn the basis, the influence mechanism of the TFC-FO membrane on the performance of the TFC-FO membrane is disclosed, the method is a new subject in the fields of environmental engineering and material chemistry, and simultaneously achieves the aims of improving the high water flux and the anti-pollution performance of the TFC-FO membrane under the conditions of sewage treatment and pollution, thereby having great theoretical significance and application value.
Drawings
FIG. 1 is TiO 2 Schematic diagram of the preparation of a PTFE support layer modified forward osmosis photocatalytic membrane.
Detailed Description
The following description of the preferred embodiments of the present invention is provided for the purpose of better illustrating the invention and is not intended to limit the invention thereto.
The test method comprises the following steps:
1. method for testing water flux:
the mass of one side of the drawing liquid is recorded continuously through an automatic counting balance, and the water flux can be obtained according to the formula (1) through the change of the mass of the drawing liquid before and after operation:
in the formula, J W Denotes the water flux of the membrane, L.m -2 ·h -1 (ii) a Δ V represents the volume of the raw material solution that permeates the membrane, L; Δ t represents the time of the test experiment, h; a. the m Represents the effective area of the film, m 2 。
2. Method for testing salt flux:
the ion concentration can be calculated by testing the conductivity of the raw material solution before and after operation, and the reverse salinity flux can be obtained by using a formula (2) according to the volume change of the raw material solution before and after operation:
in the formula, J s Is the reverse salt flux of the membrane, g.m -2 ·h -1 ；C 0 And C t Salt concentrations of the starting and end feed solutions, respectivelyDegree, mg. L -1 ；V 0 And V t The volume of the starting and ending feed solution, L, respectively; Δ t represents the experimental time, h; a. the m Represents the effective area of the film, m 2 。
The raw materials and methods used in the examples:
the polyether sulfone support layer is PES basement membrane with the aperture of 0.22 mu m and the diameter of 47mm, and is purchased from GVS of Germany;
the reagents or instruments used are not indicated by manufacturers, and are all conventional products which can be obtained by market;
the procedures or conditions not specifically mentioned are those described in the literature of the art or in the product description.
Example 1
Preparation of TiO 2 -a method for forward osmosis photocatalytic membranes modified with a PTFE support layer, comprising the steps of:
(1)TiO 2 preparation of PTFE dispersion:
fully mixing 0.38g of 60 wt% PTFE emulsion with 99.62mL of deionized water to obtain a diluted solution of the PTFE emulsion;
5.45g of TiO was added to a dilution of PTFE emulsion 2 Carrying out 100W ultrasonic treatment on nano particles (the particle size is 3-5 nm) for 10min, and uniformly mixing to obtain TiO 2 -a PTFE dispersion;
(2)TiO 2 preparation of the PTFE modified layer:
1.2mL of TiO from step (1) 2 The PTFE dispersion was poured at 7.065cm 2 On the supporting layer of polyethersulfone, putting the supporting layer into a drying oven at 60 ℃ for heating for 25min to obtain TiO 2 -a PTFE modified layer;
(3) preparation of TiO 2 PTFE support layer modified forward osmosis photocatalytic membrane:
generating a PA layer through interfacial polymerization to obtain the TiO 2 -a PTFE support layer modified forward osmosis photocatalytic membrane, in particular as follows: using a polytetrafluoroethylene plate frame, a rubber ring, a glass plate and a metal clamp to clamp the TiO of the step (2) 2 The PTFE modified layer was fixed downward, 6.70mL of a 2% by mass solution of m-phenylenediamine was poured onto the membrane surface at 20 deg.CSoaking for 1min, and removing redundant m-phenylenediamine; then pouring 7.33mL of trimesoyl chloride solution with the mass fraction of 0.1% on the surface of the membrane, reacting for 2min at the temperature of 20 ℃, draining, then placing in a hot water bath at the temperature of 100 ℃ for thermal crosslinking reaction for 5min, and obtaining the TiO after the reaction is finished 2 -a PTFE support layer modified forward osmosis photocatalytic membrane.
Comparative example 1
A method of making a conventional TFC-FO membrane comprising the steps of:
fixing the fully soaked polyether sulfone support layer by using a plate frame, pouring 6.70mL of m-phenylenediamine solution with the mass fraction of 2% onto the surface of the membrane, soaking at 20 ℃ for 1min, and removing the m-phenylenediamine solution remained on the membrane surface by using a rubber roller after soaking; and then 7.33mL of trimesoyl chloride solution with the mass fraction of 0.1% is poured onto the membrane surface, the reaction is carried out for 2min at the temperature of 20 ℃, the membrane is placed in a hot water bath at the temperature of 100 ℃ after draining, the thermal cross-linking reaction is carried out for 5min, and the conventional TFC-FO membrane is obtained after the reaction is finished.
Comparative example 2
Omitting TiO from example 1 2 The nanoparticles, otherwise in accordance with example 1, resulted in a PTFE support layer modified TFC-FO membrane.
Comparative example 3
Adjusting TiO in example 1 2 The nano-particles (with the particle diameter of 3-5 nm) are TiO 2 P25 particles (the particle size is 100-200 nm), and the rest is consistent with the embodiment 1, so as to obtain the PTFE-P25 support layer modified TFC-FO membrane.
TiO with particle size less than 10nm under the condition of the same loading amount 2 The performance of the modified TFC-FO membrane is obviously better than that of the TFC-FO membrane modified by the P25 supporting layer with larger particle size.
Comparative example 4
The diluted solution of PTFE emulsion in example 1 was an aqueous dispersion of dopamine (PDA), the concentration of the dispersion was 2mg/mL, the deposition time was 30 hours, and the rest was the same as that in example 1, to obtain TiO 2 -a PDA support layer modified forward osmosis photocatalytic membrane.
Compared with PDA, the PTFE emulsion has the advantages that: the modification time is greatly shortened from 30h is shortened to 25min, and meanwhile, the water flux, the reverse salt flux and the specific salt flux of the obtained modified membrane have no obvious difference. Moreover, PTFE can act to increase the mechanical strength of the membrane material, making TiO available 2 The service life of the PTFE modified membrane is far higher than that of TiO 2 -PDA modified membranes. TiO 2 2 The PTFE modified membrane keeps better permeability in long-term operation, while TiO 2 The PDA modified membrane broke after 72h of continuous operation, with a significant drop in rejection.
Comparative example 5
Example 1 step (3) was adjusted to TiO 2 After deposition of PTFE on a support layer of polyethersulfone, on TiO 2 The PTFE side is subjected to interfacial polymerization to form a PA layer, giving TiO 2 -PTFE intermediate layer modified TFC-FO membrane.
Because PTFE is a super-hydrophobic material, the membrane material obtained by the method is not firm, and the polyamide layer is easy to fall off.
Comparative example 6
Adjusting the embodiment 1, firstly carrying out interfacial polymerization reaction on a polyether sulfone support layer to generate a PA layer to obtain a conventional TFC-FO membrane, and then carrying out TiO precipitation 2 PTFE on the PA layer side to give TiO 2 PTFE surface modified TFC-FO membranes.
As a result, it was found that: due to TiO 2 The PTFE loading process breaks the PA layer, resulting in a large drop in membrane rejection.
The permeability of the membranes obtained in example 1 and comparative examples 1 to 6 are shown in table 1:
TABLE 1 permeation Properties of the membranes
Note: "/" no test can be performed.
Example 2
The anti-pollution performance test method of the forward osmosis photocatalytic membrane comprises the following steps:
the specific experimental conditions were as follows: placing the forward osmosis photocatalytic membrane in a membrane assembly and carrying out a pollution experiment for 16h, wherein the feed solution is 500mL of 200ppm BSA solution, the draw solution is 1L of 1M NaCl solution, and one side of the modified layer faces to the feed solution; the pump speeds of the feed and draw side peristaltic pumps were both 17.4 rpm. And a 300W xenon lamp is used for irradiation in the pollution process, and the distance between a xenon lamp light source and the surface of the film is 10 cm.
The membranes synthesized in example 1 and comparative examples 1 to 6 were subjected to an anti-contamination test, and the test results are shown in the following table 2:
TABLE 2 anti-fouling behaviour of the membranes
Note: "/" no test can be performed.
Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (10)
1. Preparation of TiO 2 -a method for forward osmosis photocatalytic membranes modified by a PTFE support layer, characterized in that it comprises the following steps:
(1)TiO 2 preparation of PTFE dispersion:
adding TiO into the diluted PTFE emulsion 2 Mixing the nano particles evenly by ultrasonic to obtain TiO 2 -a PTFE dispersion;
(2)TiO 2 preparation of the PTFE modified layer:
mixing the TiO obtained in the step (1) 2 Depositing the PTFE dispersion on a polyether sulfone support layer by heating in an oven to obtain TiO 2 -a PTFE modified layer;
(3) preparation of TiO 2 -PTFE support layer modified forward osmosis photocatalytic membrane:
mixing the TiO obtained in the step (2) 2 The PTFE surface modification layer was fixed downward and m-benzene was addedPouring a diamine solution on the surface of the membrane, and removing redundant m-phenylenediamine after soaking; then pouring the trimesoyl chloride solution on the surface of the membrane for reaction, draining the membrane, then carrying out thermal crosslinking reaction in a hot water bath, and obtaining the TiO after the reaction is finished 2 -a PTFE support layer modified forward osmosis photocatalytic membrane.
2. The method according to claim 1, wherein the TiO in step (1) 2 The particle size of the nano-particles is 3 nm-5 nm.
3. The method of claim 1, wherein the PTFE emulsion of step (1) and TiO 2 The mass ratio of the nano particles is 0.38: 5.45.
4. the method according to claim 1, wherein the TiO in the step (2) 2 The amount of the PTFE dispersion is 0.1 to 0.2mL/cm 2 。
5. The method according to claim 1, wherein the m-phenylenediamine solution in the step (3) is used in an amount of 2-4% by mass, the soaking time is 1-10 min, and the soaking temperature is 15-25 ℃.
6. The method according to claim 1, wherein the mass fraction of the trimesoyl chloride solution in the step (3) is 0.1-0.2%, the reaction is carried out for 1-10 min, and the reaction temperature is 15-25 ℃.
7. The method according to claim 1, wherein the thermal crosslinking reaction in step (3) is a thermal crosslinking reaction in a hot water bath at 80-100 ℃ for 2-5 min.
8. TiO produced by the method according to any one of claims 1 to 7 2 -a PTFE support layer modified forward osmosis photocatalytic membrane.
9. A water treatment apparatus or plant, characterized in thatCharacterized by comprising the TiO of claim 8 2 -a PTFE support layer modified forward osmosis photocatalytic membrane.
10. The TiO of claim 8 2 -use of a PTFE support layer modified forward osmosis photocatalytic membrane for water treatment.
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