Thin Film Composite Membrane with Nano-sized Bubbles Having Enhanced Membrane Permeability, Preparation Methods and Uses Thereof

• US 20200129931A1
• Filed: 04/19/2018
• Published: 04/30/2020
• Est. Priority Date: 04/19/2017
• Status: Active Grant

• Current Assignee: University of Hong Kong (Government of Hong Kong Special Administrative Region)
• Original Assignee: University of Hong Kong (Government of Hong Kong Special Administrative Region)
• Inventors: MA, Xiaohua, TANG, Chuyang
• Granted Patent: US 11,148,102 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 2323/21817 Salts
• CPC Class Codes: B01D 2323/40 in-situ membrane formation
• CPC Class Codes: B01D 2323/48 Influencing the pH
• CPC Class Codes: B01D 2325/0283 Pore size
• CPC Class Codes: B01D 67/0006 by chemical reactions in-situ polymerisation, polycondensation, cross-linking or reaction for manufacturing composite membranes B01D69/125
• CPC Class Codes: B01D 67/0013 Casting processes
• CPC Class Codes: B01D 67/003 by selective elimination of components, e.g. by leaching
• CPC Class Codes: B01D 69/02 characterised by their properties
• CPC Class Codes: B01D 69/107 Organic support material
• CPC Class Codes: B01D 69/1251 by interfacial polymerisation
• CPC Class Codes: B01D 71/56 Polyamides, e.g. polyester-amides
• CPC Class Codes: B01D 71/68 Polysulfones; Polyethersulfones

Abstract

Thin film composite membrane with nano-sized bubbles having enhanced membrane permeability, preparation methods and uses thereof are provided. The method of preparation of a thin film composite membrane, comprising: a) an aqueous solution containing at least an amine, and b) an organic solution containing at least a polyfunctional acyl halide, an additive or soluble gas being present in a) and/or b), or a nano-bubble generator or ultrasound are used to generate nano-bubbles in a) and/or b). Interfacial polymerization of a) and b) occurs at or near the surface of a porous support membrane. The advantage of creating nano-sized bubbles in the separating layer of membrane is that it can reduce membrane resistance without sacrificing the mechanical strength and stability of the membrane so as to improve its water permeability, salt rejection and antifouling. In addition, the process is simple to adopt while performance improvement of the membrane is remarkable.

Claims

1. A method of fabricating a thin film composite membrane, comprising the steps of:

adding a certain amount of NaHCO₃ in a 1,3-phenylendiamine (MPD) aqueous solution, wherein the concentration of NaHCO₃ in the MPD aqueous solution is in the range from 0 to the saturated concentration;

preferably, the concentration of MPD in the MPD aqueous solution is in the range of 0.01˜

10.0 wt. %;

pouring the MPD aqueous solution on the top surface of a polysulfone substrate and allowing it to soak for 10 seconds-5 hours;

carefully removing the excess MPD aqueous solution from the membrane surface by rolling it with a rubber roller;

pouring a 1,3,5-benzenetricarbonyl trichloride (TMC) hexane solution with a concentration of 0.0005-2.0 wt. % onto the MPD-soaked membrane substrate to get a reaction in 5 seconds-30 min, so that a thin film is formed via interfacial polymerization;

draining the hexane solution from the thin film membrane;

placing the membrane in warm water at 25-80 degrees centigrade for 0-30 min; and

treating the membrane with HCl for 0-48 hours.

2. The method of fabricating a thin film composite membrane according to claim 1 further including the step of storing the membrane in deionized water.

3. The method of fabricating a thin film composite membrane according to claim 1 further including the step of adding NaHCO₃ during interfacial polymerization.

4. The method of fabricating a thin film composite membrane according to claim 1 wherein the HCl has a pH of about 3.5.

5. The method of fabricating a thin film composite membrane according to claim 1 wherein the polysulfone substrate is fabricated by the steps of:

dissolving polysulfone (PSf) beads in N,N-Dimethylformamide (DMF) at 50°

C. until homogeneous and transparent in order to form a polymer solution with a concentration of 15.0 wt. %;

using the polymer solution as a casting solution to prepare a porous substrate;

cooling the casting solution down to room temperature;

degassing the casting solution statically in the same container;

spreading the casting solution directly onto a smooth and clean glass plate with a certain thickness determined by a casting knife; and

immersing immediately the glass plate with the whole composite in deionized water as a coagulant bath at room temperature for at least 5 min to finish the phase inversion to form the polysulfone substrate.

6. The method of fabricating a thin film composite membrane according to claim 5 wherein the polysulfone substrate is stored in deionized water prior to having the MPD aqueous solution poured on its top surface.

7. A thin film composite membrane made according to a method of claim 1 comprising a top layer of cross-linked polyamide.

8. A thin film composite membrane made according to the method of claim 3 comprising a top layer of cross-linked polyamide with nano-sized pores created by CO₂.

9. The thin film composite membrane of claim 8 wherein the pores are nano-sized bubbles, nano-bubbles, nano-sized pores, nano-pores, nano-sized voids or nano-voids.

22. Use of a thin film composite membrane fabricated according to a method of claim 1, or a thin film composite membrane according to claim 21 in reverse osmosis (RO), nano-filtration (NF), forward osmosis (FO), pressure retarded osmosis (PRO), or chemical applications (e.g., batteries, fuel cells).

10. A method of fabricating a thin film composite membrane, comprising the steps of:

adding an certain amount of CuO nano-particles in a 1,3-phenylendiamine (MPD) aqueous solution with a concentration of 0.01˜

10.0 wt. %;

pouring the MPD aqueous solution on the top surface of a polysulfone substrate and allowing it to soak for 10 seconds-5 hours;

carefully removing the excess MPD aqueous solution from the membrane surface by rolling it with a rubber roller;

pouring a 1,3,5-benzenetricarbonyl trichloride (TMC) hexane solution with a concentration of 0.0005-2.0 wt. % onto the MPD-soaked membrane substrate to get a reaction in 5 seconds-30 min, so that a thin film is formed via interfacial polymerization;

draining the hexane solution from the thin film membrane;

placing the membrane in warm water at 25-80 degrees centigrade for 0-30 min; and

treating the membrane with HCl for 0-48 hours.

21. A thin film composite membrane fabricated according to a method of claim 10.

11. A method of fabricating a thin film composite membrane, comprising the steps of:

pressing a certain amount of a soluble gas into a 1,3-phenylendiamine (MPD) aqueous solution at 0-10 bar for 0-2 hours, preferably, the concentration of MPD in the MPD aqueous solution is in the range of 0.01˜

10.0 wt. %;

pouring the MPD aqueous solution on the top surface of a polysulfone substrate and allowing it to soak for 10 seconds-5 hours;

carefully removing the excess MPD aqueous solution from the membrane surface by rolling it with a rubber roller;

pouring a 1,3,5-benzenetricarbonyl trichloride (TMC) hexane solution with a concentration of 0.0005-2.0 wt. % onto the MPD-soaked membrane substrate to get a reaction in 5 seconds-30 min, so that a thin film is formed via interfacial polymerization;

draining the hexane solution from the thin film membrane; and

placing the membrane in warm water at 25-80 degrees centigrade for 0-30 min.

12. The method of claim 11 wherein the soluble gas is N₂, CO₂, O₂, SO₂, H₂, CH₄, H₂S, chlorine, ammonia, or vapor of volatile organic solvents.

13. A method of fabricating a thin film composite membrane, comprising the steps of:

subjecting a certain amount of a 1,3-phenylendiamine (MPD) aqueous solution to ultrasonic vibration of 0 to 2 hours, preferably, the concentration of MPD in the MPD aqueous solution is in the range of 0.01˜

10.0 wt. %, and more preferably, ultrasonic intensity of the ultrasonic vibration is more than 0 and less than 1 W/cm²;

pouring the MPD aqueous solution on the top surface of a polysulfone substrate and allowing it to soak for 10 seconds-5 hours;

carefully removing the excess MPD aqueous solution from the membrane surface by rolling it with a rubber roller;

pouring a 1,3,5-benzenetricarbonyl trichloride (TMC) hexane solution with a concentration of 0.0005-2.0 wt. % onto the MPD-soaked membrane substrate to get a reaction in 5 seconds-30 min, so that a thin film is formed via interfacial polymerization;

draining the hexane solution from the thin film membrane;

placing the membrane in warm water at 25-80 degrees centigrade for 0-30 min.

14. A method of fabricating a thin film composite membrane, comprising the steps of adding additives in a reaction system, introducing reactions to release gases in a reaction system, using solutions with supersaturated gases in a reaction system, pressuring soluble gases in a reaction system, altering temperature or pH of a reaction system, ultrasound of a reaction system, and/or using nano-bubble generator in a reaction system;

wherein the reaction system is a 1,3-phenylendiamine (MPD) aqueous solution with a concentration of 0.01˜

10.0 wt. %;

pouring the MPD aqueous solution on the top surface of a polysulfone substrate and allowing it to soak for 10 seconds-5 hours;

carefully removing the excess MPD aqueous solution from the membrane surface by rolling it with a rubber roller;

pouring a 1,3,5-benzenetricarbonyl trichloride (TMC) hexane solution with a concentration of 0.0005-2.0 wt. % onto the MPD-soaked membrane substrate to get a reaction in 5 seconds-30 min, so that a thin film is formed via interfacial polymerization;

draining the hexane solution from the thin film membrane;

placing the membrane in warm water at 25-80 degrees centigrade for 0-30 min; and

treating the membrane with HCl for 0-48 hours.

15. The method of claim 14 wherein the additives are salts of bicarbonate, carbonate, CuO nano-powder/nanoparticles, or pure metals (e.g., zero valent iron).

16. The method of claim 14 wherein the additives will 1) decompose or react with at least one reactant or at least one product during reaction, or 2) be dislodged by post-treatment, or 3) release volatile vapor(s) to generate nano-sized bubbles.

17. A separating layer of membrane made according to a method of claim 14, wherein the separating layer is thin film, active layer or separating skin layer.

18. The method of claim 14, wherein the interfacial polymerization process is for preparing thin film composite membrane, comprises:

a) an aqueous solution containing at least an amine,

b) an organic solution containing at least a polyfunctional acyl halide, and

wherein interfacial polymerization of a) and b) occurs at or near the surface of a porous support membrane (porous substrate).

19. The method of claim 18 wherein the porous support membrane is polysulfone (PSf), polyethersulfone (PES), polyvinyl chloride (PVC), polyacrylonitrile (PAN), polycarbonate, polyphenylene oxides, poly(styrene-co-acrylonitrile), poly(phthalazinone ether sulfone ketone) (PPESK), polyetherimide, polypropylene or others by conventional phase inversion techniques.

20. The method of claim 14 wherein the thin film composite membrane is for use in reverse osmosis (RO), nano-filtration (NF), forward osmosis (FO), pressure retarded osmosis (PRO), or chemical applications (e.g., batteries, fuel cells).