Preparation method of PTFE composite nanofiltration membrane for water filtration purification

A composite nanofiltration membrane, filtration and purification technology, applied in the field of water treatment, can solve the problems of reduced membrane surface area, reduced rejection rate of nanofiltration membrane, and shedding of the intercepted layer

Inactive Publication Date: 2019-11-15
陈圆圆
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The problem of using polytetrafluoroethylene as the base membrane of the nanofiltration membrane is that polytetrafluoroethylene shrinks violently under heating conditions, resulting in a decrease in the surface area of ​​the membrane, and the interception formed by interfacial polymerization on the surface of the polytetrafluoroethylene base membrane. Due to the contraction force of the polytetrafluoroethylene-based membrane, the binding force between the intercepting layer and the base membrane is weakened, and the intercepting layer is easy to fall off from the surface of the polytetrafluoroethylene-based membrane during hydraulic operation; The effect of internal mutual extrusion is likely to cause the reduction of the strength of the interception layer, and the reduction of the rejection rate of the nanofiltration membrane after long-term operation

Method used

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  • Preparation method of PTFE composite nanofiltration membrane for water filtration purification
  • Preparation method of PTFE composite nanofiltration membrane for water filtration purification

Examples

Experimental program
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Effect test

Embodiment 1

[0027] The preparation method of the PTFE composite nanofiltration membrane that is used for water filtration and purification comprises the following steps:

[0028]1) Get carboxymethyl chitosan and add it into deionized water and stir and dissolve, and be mixed with a carboxymethyl chitosan aqueous solution with a mass concentration of 5%; The ratio of mass ratio is 1:0.2, the hydrophobic polytetrafluoroethylene ultrafiltration base membrane is immersed in the carboxymethyl chitosan aqueous solution, soaked for 3h, after taking out, it is naturally dried to obtain the hydrophilic modified polytetrafluoroethylene ultrafiltration base membrane ;

[0029] 2) Take sodium alginate and add it into deionized water, stir and dissolve, and prepare a sodium alginate aqueous solution with a concentration of 3%;

[0030] According to the ratio of the mass ratio of the hydrophilic modified polytetrafluoroethylene ultrafiltration base membrane to sodium alginate of 1:0.25, the hydrophili...

Embodiment 2

[0037] The preparation method of the PTFE composite nanofiltration membrane that is used for water filtration and purification comprises the following steps:

[0038] 1) Get carboxymethyl chitosan and add in deionized water and stir and dissolve, and be mixed with a carboxymethyl chitosan aqueous solution with a mass concentration of 2%; The ratio of mass ratio is 1:0.4, the hydrophobic polytetrafluoroethylene ultrafiltration base membrane is immersed in the carboxymethyl chitosan aqueous solution, soaked for 2h, after taking it out, it is naturally dried to obtain the hydrophilic modified polytetrafluoroethylene ultrafiltration base membrane ;

[0039] 2) Take sodium alginate and add it into deionized water, stir and dissolve, and prepare a sodium alginate aqueous solution with a concentration of 6%;

[0040] According to the ratio of the mass ratio of the hydrophilic modified polytetrafluoroethylene ultrafiltration base membrane to sodium alginate of 1:0.3, the hydrophilic ...

Embodiment 3

[0047] The preparation method of the PTFE composite nanofiltration membrane that is used for water filtration and purification comprises the following steps:

[0048] 1) Get carboxymethyl chitosan and add in deionized water and stir and dissolve, and be mixed with a carboxymethyl chitosan aqueous solution with a mass concentration of 1%; The ratio of mass ratio is 1:0.1, the hydrophobic polytetrafluoroethylene ultrafiltration base membrane is immersed in the carboxymethyl chitosan aqueous solution, soaked for 5h, after taking it out, it is naturally dried to obtain the hydrophilic modified polytetrafluoroethylene ultrafiltration base membrane ;

[0049] 2) Take sodium alginate and add it into deionized water, stir and dissolve, and prepare a sodium alginate aqueous solution with a concentration of 5%;

[0050] According to the ratio of the mass ratio of the hydrophilic modified polytetrafluoroethylene ultrafiltration base membrane to sodium alginate of 1:0.2, the hydrophilic ...

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Abstract

The invention relates to the technical field of water treatment, and discloses a preparation method of a PTFE composite nanofiltration membrane for water filtration purification. The preparation method comprises the following steps of 1) immersing a hydrophobic polytetrafluoroethylene ultrafiltration base membrane in a carboxymethyl chitosan solution to obtain a hydrophilic modified polytetrafluoroethylene ultrafiltration base membrane; 2) immersing the hydrophilic modified polytetrafluoroethylene ultrafiltration base membrane into a sodium alginate solution, adding rod-shaped nano zinc oxide,and dropwise adding a calcium chloride solution for a reaction to obtain an intermediate polytetrafluoroethylene ultrafiltration base membrane; 3) immersing the intermediate polytetrafluoroethylene ultrafiltration base membrane into a polyethyleneimine solution, taking out the base membrane, and immersing the base membrane in a trimesoyl chloride solution for an interfacial polymerization reaction to obtain a nascent-state composite nanofiltration membrane; 4) placing the nascent-state composite nanofiltration membrane in an oven for heating, curing and cross-linking to obtain the PTFE composite nanofiltration membrane. According to the preparation method, the polytetrafluoroethylene base membrane is not severely shrunk under heating conditions, and the reduction of the binding force of acomposite nanofiltration membrane retaining layer and the base membrane is avoided.

Description

technical field [0001] The invention relates to the technical field of water treatment, in particular to a preparation method of a PTFE composite nanofiltration membrane used for water body filtration and purification. Background technique [0002] Nanofiltration membrane is a new type of membrane separation material developed in the 1980s. The cut-off relative separation mass limit of the membrane is 200-1000 Daltons, and the membrane pore diameter corresponding to the cut-off relative molecular mass is 1-3nm. This type of membrane is called a nanofiltration membrane, which is between the ultrafiltration membrane and the reverse osmosis membrane. Compared with the reverse osmosis membrane, the operating pressure is about 0.7MPa, which is lower than the reverse osmosis membrane, so it is also called loose reverse osmosis or low pressure. Reverse osmosis nanofiltration, a new membrane separation technology based on reverse osmosis developed in the 1980s, has gained more and m...

Claims

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Application Information

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IPC IPC(8): B01D69/12B01D71/36B01D67/00C02F1/44
CPCB01D61/027B01D67/0079B01D69/125B01D71/36C02F1/442
Inventor 陈圆圆
Owner 陈圆圆
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