Composite thin membrane with multilayer composite structure and preparation method thereof

A transition layer and membrane surface technology, applied in the field of semi-permeable membrane separation technology, can solve the problems of low porosity, difficult operation, high energy consumption, etc., and achieve the effect of reducing membrane energy consumption, expanding application fields, and simple equipment requirements

Inactive Publication Date: 2017-05-31
林小锋
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the biggest disadvantage of the traditional thin film composite membrane structure is that the porous support layer is relatively dense and has low porosity, which hinders the passage of water and limits its maximum water flux.
However, electrospinning requires thousands or even tens of thousands of volts of high voltage. Not only is it difficult to operate, high energy consumption, and low output, but also the types of membranes that can be applied are very limited. In addition, the diameter of ultrafine fibers produced by electrospinning exceeds 300nm, which greatly limits the specific surface area and membrane performance of the fiber

Method used

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  • Composite thin membrane with multilayer composite structure and preparation method thereof
  • Composite thin membrane with multilayer composite structure and preparation method thereof
  • Composite thin membrane with multilayer composite structure and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] A 200 µm thick porous polysulfone support layer substrate including a backing non-woven fabric was coated with a nanocellulose transition layer according to the following steps:

[0040] (1) Preparation of nanocellulose acetate sodium by TEMPO method: 20g of never-dried softwood chemical pulp fiber was placed in a trough beater and 1500g of water was added. After thawing for 40min, 0.25g of TEMPO, 2.5g of NaBr and 5mL of 12% NaClO solution by mass percentage, stirring for full reaction, adding 0.5 molar concentration of sodium hydroxide solution and 0.5 molar concentration of hydrochloric acid solution from time to time to maintain the pH of the slurry at 10.5 After reacting for 24 hours, the oxidized fiber and waste water were separated to obtain oxidized fiber with a carboxyl content of 0.30 mmol / g; the obtained oxidized fiber was nano-treated using a high-pressure homogenizer to obtain a uniform and transparent sodium acetate nanocellulose solution;

[0041] (2) The ...

Embodiment 2

[0055] The process described in Example 1 is basically the same, but the number of repetitions of steps (4) to (7) in step (8) is 5 times to obtain the nanocellulose transition layer of 6 double-layer nanostructures, and other parameters are different. Change. After testing, the salt rejection rate of the obtained composite membrane was 98.8%, and the flux was 3.1 L / m 2 h.

Embodiment 3

[0057] The process described in Example 1 is basically the same, but the number of repetitions of steps (4) to (7) in step (8) is 20 times to obtain 21 nanocellulose transition layers of double-layer nanostructure, and other parameters are different. Change. After testing, the salt rejection rate of the obtained composite membrane was 99.2%, and the flux was 3.0 L / m 2 h.

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Abstract

The invention belongs to the technical field of semi-permeable membrane separation processes, and relates to a composite thin membrane with a multilayer composite structure and a preparation method thereof. The composite thin membrane is formed by coating nano-cellulose and a transition layer which is formed from a polyelectrolyte by a layer-by-layer assembling method on a porous supporting layer substrate in sequence, and then coating a polyamide selective membrane layer which is formed through a common interface polymerization reaction method. A composite thin membrane structure can be applied to preparation of a nano-filtration membrane, a reverse osmosis membrane and a forward osmosis membrane. The application of the composite thin membrane with the multilayer composite structure comprises tap water purification, municipal water supply, sewage purification, brackish water desalination, seawater desalination, drink juice concentration process, dairy industry, blood dialysis medicine industry and semiconductor industry.

Description

technical field [0001] The invention belongs to the technical field of semipermeable membrane separation technology, relates to a thin film composite membrane with a multilayer composite structure and a preparation method thereof, in particular to a porous support layer substrate which is sequentially coated with nanocellulose and polyelectrolyte formed by a layer-by-layer assembly method The transition layer is then coated with a polyamide selective thin film layer formed by a common interfacial polymerization method. The thin film composite membrane structure can be applied to the preparation of nanofiltration membranes, reverse osmosis membranes and forward osmosis membranes. Background technique [0002] Semi-permeable membrane separation technology refers to the technology that achieves selective separation of mixtures of molecules with different particle sizes at the molecular level when passing through a semi-permeable membrane. Semi-permeable membranes can be divided...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B32B27/34B32B27/06B32B33/00B32B37/02B32B38/08B32B38/16B01D71/10B01D69/12B01D67/00
CPCB32B27/34B01D67/0002B01D69/12B01D71/10B32B27/06B32B33/00B32B37/02B32B38/08B32B38/164
Inventor 林小锋
Owner 林小锋
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