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Polyvinylidene fluoride hollow fiber membrane and preparation method thereof

The technology of polyvinylidene fluoride and polyvinylidene fluoride resin is applied in the field of polyvinylidene fluoride hollow fiber membrane and its preparation, which can solve the problem that the hydrophilicity cannot be maintained for a long time, and the separation index of separation membrane strength, permeation amount and retention rate is affected. drop and other problems, to achieve good mechanical and chemical stability, reduce irreversible deposition, and improve the effect of anti-pollution performance

Inactive Publication Date: 2011-01-26
QINGDAO SEACON WATER SERVICE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, polyvinylidene fluoride resin has the characteristics of low surface energy and strong hydrophobicity. It has the following disadvantages when used as a water treatment membrane: first, it is easy to produce adsorption pollution (especially when it contains protein solutions), and the penetration of the membrane The main separation indicators such as the amount and rejection rate will be significantly reduced, which will shorten the actual service life of the membrane; the second is that the separation process requires a large driving force
However, the surface modification of the membrane often changes the pore size and pore size distribution of the membrane surface to a certain extent. The physical adsorption method only makes the hydrophilic polymer adsorb on the surface or inside of the membrane through physical adsorption. The water agent is very easy to lose, causing the hydrophilicity to not be maintained for a long time
Chemical modification often affects the strength of the separation membrane to a certain extent, and the treatment conditions are relatively harsh, and if the hydrophilic modification is too large, the membrane is easy to dissolve

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Nano-silica 0.5wt%, Tween-800.5wt%, N, N-dimethylacetamide 20wt%, after high-speed mechanical stirring dispersion and ultrasonic dispersion alternately, and polyvinylidene fluoride resin 20wt%, all Add 2wt% of fluorosulfonic acid resin, 5wt% of polyvinylpyrrolidone (K-30), 3wt% of ethanol, and 49wt% of N,N-dimethylacetamide into a sealed stirring tank, stir and dissolve at 85°C to form a homogeneous solution. After heat preservation at 70°C and vacuum defoaming, it is extruded through a tubular hollow fiber spinneret at the same time as the 5% dimethylacetamide aqueous solution as the internal coagulation liquid, and passes through a distance of 15 cm in the air, and enters the In the coagulation bath of the coagulation solution, the winding becomes a polyvinylidene fluoride-based film after being treated with alcohol. Then immerse the polyvinylidene fluoride-based film in 50°C, 5wt% sodium hydroxide aqueous solution for 4 hours, take it out and wash it, and immerse it ...

Embodiment 2

[0041] Nano silicon dioxide 0.5wt%, Tween-800.5wt%, N, N-dimethylacetamide 20wt%, through high-speed mechanical stirring dispersion and ultrasonic dispersion alternately, and polyvinylidene fluoride resin 18wt%, polyvinylidene fluoride resin Add vinylpyrrolidone (K-30) 6wt%, polyethylene glycol-4005wt%, N, N-dimethylformamide 20%, N, N-dimethylacetamide 30wt% into a sealed stirring tank, at 85°C Stir under low temperature to dissolve into a uniform solution. After heat preservation at 70°C and vacuum defoaming, pass through a tubular hollow fiber spinneret and extrude simultaneously with a 5% dimethylacetamide aqueous solution as an internal coagulation liquid. centimeter distance, enter the coagulation bath with water as the external coagulation liquid, and become polyvinylidene fluoride-based film after being wound up and treated with alcohol. Then immerse the polyvinylidene fluoride-based film in 50°C, 5wt% sodium hydroxide aqueous solution for 4 hours, take it out and wash...

Embodiment 3

[0043] Polyvinylidene fluoride resin 15wt%, polymethyl methacrylate-vinyl alcohol 10wt%, polyethylene glycol-400 10wt%, Tween-800.5wt%, N,N-dimethylformamide 30%, N, Add 31wt% of N-dimethylacetamide and 0.5wt% of coupling agent KH56 into a sealed stirring tank, stir and dissolve at 85°C to form a homogeneous solution A; mix 1wt% ethyl orthosilicate and 2wt% ethanol to prepare Solution B: add solution B to solution A under stirring, adjust the pH value to about 3 with acid, and react for 2 hours. After heat preservation at 70°C and vacuum defoaming, it is extruded simultaneously with 5% dimethylacetamide aqueous solution as the internal coagulation liquid through a tubular hollow fiber spinneret, passes through a distance of 20 cm in the air, and enters the In the coagulation bath of the external coagulation solution, the winding becomes a polyvinylidene fluoride base film after being treated with alcohol. Then immerse the polyvinylidene fluoride-based film in 50°C, 5wt% sodiu...

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PUM

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Abstract

The invention relates to a polyvinylidene fluoride hollow fiber membrane and a preparation method thereof, belonging to the field of chemical industry. The pore size of the membrane is 0.02-0.5 micrometers, the thickness is 0.2-0.5 millimeters, and the external diameter of membrane wires is 1-2 millimeters. A membrane making liquid comprises the following components in percentage by weight: 15-30% of polyvinylidene fluoride resin, 1-10% of hydrophilic polymer, 0.5-5% of functional polymer or polymer monomer, 0.1-5% of surfactant, 0.1-15% of inorganic or organic polymer pore-forming agent, 0.1-5% of nano additive and 40-71% of solvent. The preparation method of the polyvinylidene fluoride hollow fiber membrane comprises the following step of: effectively controlling the interfacial tension between the membrane making liquid and a solidifying liquid and the double diffusion permeation speed of the solidifying agent and the solution on the interface by properly adjusting the ratio of all components and using the surface moistening and dispersing actions of the surfactant, the dispersing and thickening actions of the pore-forming agent and the hydrophilic action of the hydrophilic substance. Thus, the hydrophilic polyvinylidene fluoride hollow fiber membrane with high permeability is prepared.

Description

technical field [0001] The invention relates to a polyvinylidene fluoride hollow fiber membrane and a preparation method thereof, belonging to the technical field of chemical product processing methods. Background technique [0002] Polyvinylidene fluoride hollow fiber membrane is a new generation of porous membrane that has appeared in recent years. Compared with other porous membranes, it has many unique and excellent properties: good heat resistance, long-term use temperature can reach 150 ° C; UV, γ-ray radiation resistance ; Strong acid and alkali resistance, long-term use range PH1-12 at room temperature; resistance to organic solvents, such as strong oxidants, aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, alcohols, aldehydes, etc. It is suitable for film production by dry-wet method or wet spinning method, and is easy to manufacture and low in cost. Therefore, it has great application value and wide application fields. However, polyvinylid...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/34B01D67/00B01D69/08D01F8/10D01F1/10D06M14/10
Inventor 赵岳轩
Owner QINGDAO SEACON WATER SERVICE TECH
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