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Method for preparing polyvinylidene fluoride hollow fiber membrane

A technology of polyvinylidene fluoride and its manufacturing method, which is applied in chemical instruments and methods, membrane technology, semi-permeable membrane separation, etc., can solve the problems of high energy consumption, complex process, poor elasticity, etc., and achieve improved elongation and improved Effect of high density, porosity, and high tensile elongation

Active Publication Date: 2013-07-31
河北诺恩水净化设备有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This method needs to control the humidity and the contact time, temperature and steam flow between the steam and the polymer film-forming liquid, and the process is complicated.
U.S. Patent (Patent No.: 5626805) discloses a complex thermally induced phase inversion technology (TIPS), which forms uniform pores on the surface of the membrane through temperature change technology. The membrane produced by this technology has high strength but poor elasticity. high energy consumption

Method used

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  • Method for preparing polyvinylidene fluoride hollow fiber membrane
  • Method for preparing polyvinylidene fluoride hollow fiber membrane
  • Method for preparing polyvinylidene fluoride hollow fiber membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] The raw materials are weighed according to the following weight percentages: 33.5% of PVDF, 55% of dimethylacetamide, 8% of ethylene glycol, 3% of polyvinylpyrrolidone, and 0.5% of dioctyl phthalate, and the specific order is: Add PVDF to dimethylacetamide, stir and dissolve, add polyvinylpyrrolidone, ethylene glycol and dioctyl phthalate together, the temperature of the membrane liquid is 40°C, continue to stir well, then filter the membrane liquid to remove air bubbles After cleaning, such as figure 1 As shown, the 70°C membrane liquid and the inner gel medium, that is, 5% dimethylacetamide aqueous solution at 70°C, are simultaneously injected into the 1# outer gel medium, that is, 14.5% carbonic acid at 75°C, through the annular spinneret 1. In the 1# gel bath 2 of the acrylic ester aqueous solution, the sprayed silk is gradually exchanged in the 1# outer gel medium, and then introduced into the drawing box 3 through the godet wheel 7, and drawn with 7 drawing wheels...

Embodiment 2

[0043] According to the preparation process and technology described in Example 1, wherein the membrane liquid consists of: PVDF 10.8%, dimethylacetamide 83%, glycerol 5%, polyvinylpyrrolidone 1%, dioctyl phthalate 0.2 %, the stirring and mixing temperature is 85°C. The temperature of the membrane-making solution obtained was 86.5°C, and the inner gel medium was changed to 25°C desalted water, and the 1# outer gel medium was a mixture of 70% propylene carbonate and 13% butyrolactone by mass percentage, The temperature is 30°C, drawing at a speed of 8m / min, and the 2# outer gel medium is also desalted water, wound to the winding wheel at a speed of 15m / min, and other process conditions are the same as in Example 1, and the into PVDF hollow fiber membrane filaments. The obtained membrane filament has an outer diameter of 1.43 mm, an inner diameter of 0.72 mm, a porosity of 88%, a pure water flux of 950 L / m2 h (0.1 Mpa, 25 °C), a tensile burst strength of 1.13 Mpa, and a tensile...

Embodiment 3

[0045] According to the preparation process and technology described in Example 1, wherein the membrane liquid consists of: PVDF 23.7%, dimethylformamide 73%, polyvinylpyrrolidone 2%, n-butanol 1%, dioctyl phthalate 0.3 %, stirring and mixing temperature is 65°C. The temperature of the obtained film-making membrane solution is 40°C, the inner gel is changed to 60% dimethylformamide aqueous solution, and the temperature is controlled at 25°C, the 1# gel medium is 60% butyrolactone solution, and the temperature is 38°C. Drawing at a speed of 28m / min, the 2# outer gel is desalted water, the temperature is 25°C, and it is wound to the winding wheel at a speed of 40m / min. Other process conditions are the same as in Example 1, and it can be made PVDF hollow fiber membrane. The obtained membrane filament has an outer diameter of 1.15 mm, an inner diameter of 0.53 mm, a porosity of 90%, a pure water flux of 750 L / m2 h (0.1 Mpa, 25 °C), a tensile burst strength of 1.8 Mpa, and a tensi...

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Abstract

The invention relates to a method for preparing a polyvinylidene fluoride hollow fiber membrane. The method comprises the steps of the preparation of a membrane liquid and the preparation of hollow fiber membrane silks, and specifically comprises the following steps of: injecting the membrane liquid and an internal gel medium into a latent solvent, namely external gel medium No. 1 of polyvinylidene fluoride by using an annular spinneret plate, drawing by using a group of traction wheels, and then making the obtained product enter gel medium No. 2, namely desalted water which is a non-solvent of the membrane liquid to ensure that the membrane silks are subjected to phase exchange formation quickly. The elasticity and flexibility of the hollow fiber membrane obtained by the method are greatly improved on the premise of ensuring higher pure water flux and strength to ensure that the membrane is more suitable for high-turbidity water quality treatment in which frequent gas washing and brushing are required, and only the stretch deformation of local membrane silk networks is caused during the gas washing and shaking of the membrane silks and the filter capacity of structural holes of other networks of the membrane is not damaged, so that the filter capacity of a membrane module cannot be influenced.

Description

technical field [0001] The invention relates to a method for manufacturing a polyvinylidene fluoride hollow fiber membrane, in particular to a method for manufacturing a highly flexible polyvinylidene fluoride hollow fiber membrane with an asymmetric structure. Background technique [0002] At present, membrane separation technology has been developed rapidly, and membrane separation has been maturely used in many fields such as sewage treatment, petrochemical industry, food and medicine, iron and steel, and electric power. At present, almost all membrane technologies rely on synthetic polymer membranes, that is, on organic high molecular compounds. The ideal membrane material should have suitable mechanical properties, high permeation flux and selectivity to the ideal permeate components. The latter two restrict each other, because higher selectivity is usually only available in small-pore membranes. Membranes have high resistance to water and tend to have low permeate flu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B01D71/34B01D69/08
Inventor 张婷朱文兵康禄光
Owner 河北诺恩水净化设备有限公司
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