Method for preparing polyvinylidene-fluoride bilayer hollow fiber membrane

A polyvinylidene fluoride, double-layer hollow technology, applied in the field of membrane separation, can solve the problems of low flux of polyvinylidene fluoride separation membranes, achieve the effect of simple membrane production equipment and methods, increase flux, and increase porosity

Inactive Publication Date: 2013-12-11
长沙奕景环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a preparation method of polyvinylidene fluoride double-layer hollow fiber membrane, which effectively solves the problem of low flux of existing commercial polyvinylidene fluoride separation membranes

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] ① Preparation of casting solution, core solution and outer gel bath

[0018] The outer layer casting solution is made of polyvinylidene fluoride polymer, the solvent N-methylpyrrolidone and the additive polyethylene glycol according to the weight percentage of 10%, 78% and 12% and mixed uniformly at 70°C; the inner layer casting solution Polyvinylidene fluoride polymer, solvent N-methylpyrrolidone and additive polyvinyl alcohol are mixed uniformly at 70°C by weight percentage of 14.25%, 85% and 0.75%; the composition of the core liquid is water; the composition of the gel bath composed of water.

[0019] ②Spinning of hollow fiber membrane

[0020] The casting liquid flows out from the outer hole of the spinneret, and the core liquid flows out from the inner hole of the spinneret at the same time, and the flow rate of the inner and outer casting liquid is 6ml / min and 2ml / min respectively, and the flow rate of the core liquid is 2.5ml / min; After passing through the air ...

Embodiment 2

[0025] Preparation of casting solution, core solution and outer gel bath

[0026] The outer film casting solution is made of polyvinylidene fluoride polymer, the solvent N-methylpyrrolidone and the additive polyvinyl pyrrolidone according to the weight percentage of 10%, 78% and 12%, and mixed uniformly at 70°C; the inner film casting solution is made of The polyvinylidene fluoride polymer, the solvent N-methylpyrrolidone and the additive polyvinyl alcohol are mixed uniformly at 70°C at 14.25%, 85%, and 0.75% by weight; the composition of the core liquid is water; the composition of the gel bath for water.

[0027] ②Spinning of hollow fiber membrane

[0028] The casting liquid flows out from the outer hole of the spinneret, and the core liquid flows out from the inner hole of the spinneret at the same time, and the flow rate of the inner and outer casting liquid is 6ml / min and 2ml / min respectively, and the flow rate of the core liquid is 2.5ml / min; After passing through th...

Embodiment 3

[0033] Preparation of casting solution, core solution and outer gel bath

[0034] The outer film casting solution is made of polyvinylidene fluoride polymer, the solvent N-methylpyrrolidone and the additive polyvinyl pyrrolidone according to the weight percentage of 10%, 78% and 12%, and mixed uniformly at 70°C; the inner film casting solution is made of The polyvinylidene fluoride polymer, the solvent N-methylpyrrolidone and the additive polyvinyl alcohol are mixed uniformly at 70 ° C by weight percentage of 13.5%, 85% and 1.5%; the composition of the core liquid is water; the composition of the gel bath for water.

[0035] ②Spinning of hollow fiber membrane

[0036] The casting liquid flows out from the outer hole of the spinneret, and the core liquid flows out from the inner hole of the spinneret at the same time, and the flow rate of the inner and outer casting liquid is 6ml / min and 2ml / min respectively, and the flow rate of the core liquid is 2.5ml / min; After passing ...

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Abstract

The invention relates to the technical field of membrane separation and particularly relates to a method for preparing a polyvinylidene-fluoride bilayer hollow fiber membrane. According to the method, aiming at the problem that the flux of the general commercial polyvinylidene fluoride separation membranes is relatively low, a scheme of spinning a bilayer polyvinylidene fluoride membrane, adding additives into an outer layer membrane and adding hydrophilic polymers of different concentrations into an inner layer so as to improve the hydrophilicity of the bilayer polyvinylidene fluoride membrane is designed, and membrane distillation membranes with higher flux are prepared.

Description

[0001] technical field [0002] The invention relates to the technical field of membrane separation, in particular to a preparation method of a polyvinylidene fluoride double-layer hollow fiber membrane. Background technique [0003] Polyvinylidene fluoride is a semi-crystalline polymer. Because of its short C-F bond length and strong bond energy, it has excellent physical and chemical properties such as high temperature resistance, corrosion resistance, high strength and good toughness. Due to its good hydrophobic properties, it has become one of the most popular hydrophobic membrane materials. The main problem with PVDF materials is that the mechanical strength of the membrane filaments is not high enough after film formation, but we can improve the strength by crosslinking. However, in the process of film production using co-extrusion technology, defects such as eccentricity of the film filaments and a small amount of deviation in the wall thickness of the film filaments...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/34B01D67/00B01D69/08
Inventor 蒋兰英宋正伟
Owner 长沙奕景环保科技有限公司
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