Preparation method of hydrophilic ultra-filtration membrane

A hydrophilic and ultrafiltration membrane technology, applied in the field of membrane separation, can solve problems such as cumbersome operation, membrane performance degradation, and membrane loss, and achieve the effects of inhibiting the hydrolysis of metal ions, improving the mechanical strength of the membrane, and ensuring stability

Active Publication Date: 2012-11-07
西安金藏膜环保科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] At present, the hydrophilization modification method of ultrafiltration membrane is mainly through surface modification and blending modification. As reported in CN101439265A, high-temperature plasma is used to trigger the membrane surface to carry out hydrophilization graft modification. Although this method is firm, it is strongly The chemical conditions of the membrane are easy to cause the deterioration of the membrane performance, and the operation is cumbersome, the surface modification layer is easy to fall off, and the internal performance of the membrane has not been effectively improved, and the modification effect is not ideal.
[0005] CN101164679A has reported the blending modification of PVDF ultrafiltration membrane and hydrophilic inorganic matter, but because the compatibility between inorganic material and macromolecular polymer is poor, thus hydrophilic modification effect can't reach actual demand
Dissolving hydrophilic polymers such as PVP, PVA, PEG, etc. in a solvent with the main material of the membrane to form a homogeneous casting solution, and forming a membrane through the phase inversion method can significantly improve the hydrophilicity of the ultrafiltration membrane surface, but PVP, PEG, etc. are soluble in water, and PVP, PEG, PVA, etc. can be used as effective porogens for ultrafiltration membranes. At the same time, such blended membranes are not fixed with hydrophilic additives, and the membranes may be damaged during long-term operation. Gradual loss with filtration operation, eventually leading to hydrophilic instability and deterioration of membrane performance

Method used

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  • Preparation method of hydrophilic ultra-filtration membrane
  • Preparation method of hydrophilic ultra-filtration membrane
  • Preparation method of hydrophilic ultra-filtration membrane

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Step 1, preparation of casting solution: by mass percentage, 18%PVDF, 3%PVA, 0.01%FeCl 3 , 3% LiCl and 76% solvent DMAc were stirred and dissolved at 90°C for 20 hours, and the casting solution was obtained after standing at 80°C for defoaming;

[0039] Step 2, preparation of nascent base film: Pour the casting solution prepared in step 1 onto a clean and flat glass plate at room temperature, and then scrape it with a stainless steel rod with 0.3mm copper wires tied at both ends to obtain the thickness 0.3mm nascent basement film;

[0040] Step 3, phase separation and curing treatment:

[0041] Pre-evaporate the nascent basement film for 5 seconds;

[0042] Then, under the condition of 30°C, put the nascent basement membrane into a hydrochloric acid aqueous solution with a pH of 2 and treat it in a gel bath for 0.5h to obtain a pre-cured nascent basement membrane;

[0043] Then, the pre-cured nascent base film is rinsed with water at room temperature to remove residu...

Embodiment 2

[0049] Different from Example 1, the mass proportion is 13%PVDF, 1%PVA, 3%TiCl 4 , 3% LiCl and 80% DMAc were mixed, the above mixture was placed at 90°C, stirred for 20h, and left to defoam at 80°C to obtain a uniform casting solution; at room temperature and relative humidity of 36%, the casting solution was placed in A nascent basement film with a thickness of 0.3mm is scraped on a flat glass plate, and the pre-evaporation time is 5 seconds. The gel phase is separated in a hydrochloric acid aqueous solution at 30°C and PH=2 and kept in a coagulation bath for 60 minutes, and then moved to clean water. Rinse repeatedly until the solvent is completely removed, soak in 30% glycerol aqueous solution for 12 hours, take it out and dry it naturally in the air to obtain a hydrophilic PVDF ultrafiltration membrane.

[0050] Under the conditions of 25°C and 0.1MPa, it is measured that the mechanical strength of the hydrophilic ultrafiltration membrane prepared in this example is 2.35-2...

Embodiment 3

[0053] Different from Example 1, the mass ratio is 14%PVDF, 15%PVP, 0.9%FeCl 3 , 3% LiCl was mixed with 67% solvent DMAc, the above mixture was placed at 60°C, stirred for 16 hours, and left to defoam at 80°C to obtain a homogeneous casting solution; at room temperature and relative humidity of 40%, the casting solution was Scrape a nascent base film with a thickness of 0.3mm on a flat glass plate, pre-evaporate for 10 seconds, immerse in 60°C, PH=2 hydrochloric acid aqueous solution for phase separation treatment for 120 minutes, move to clean water and rinse repeatedly until the solvent is completely removed , soaked in a 30% glycerol aqueous solution for 24 hours, took it out and dried it naturally in the air to obtain a hydrophilic PVDF ultrafiltration membrane.

[0054] At 25°C and 0.1 MPa, the water flux of the hydrophilic ultrafiltration membrane prepared in this example was measured to be 1035 L / m 2 h, the mechanical strength is 2.45MPa, the hydrophilic contact angle ...

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Abstract

The invention provides a preparation method of a hydrophilic ultra-filtration membrane, wherein the method comprises the following steps: introducing high-valence metal salt containing Fe3+, Al3+ and the like into film casting solution to perform cross-linking reaction with hydrophilic additives in the film casting solution so as to limit dissolution and loss behaviors of the water-soluble hydrophilic additives in film forming and running processes. The method is convenient to operate and easy to control, applicable to preparing the hydrophilic macromolecular ultra-filtration membrane by a dry or wet process, fixing the hydrophilic additives containing oxygen and nitrogen functional groups, such as polyvinyl alcohol (PVA), polyethylene glycol (PEG), polyethylene oxide (PEO) and polyvinyl pyrrolidone (PVP). The method is capable of effectively improving and stabilizing the hydrophilic property of the ultra-filtration membrane and resolving easy loss and uneven distribution problems of the hydrophilic additives in the prior art.

Description

technical field [0001] The invention belongs to the technical field of membrane separation, and mainly relates to a preparation method of a hydrophilic ultrafiltration membrane. Background technique [0002] Ultrafiltration technology is widely used in the separation, concentration and purification of biological products, pharmaceutical products and food industry. It is one of the new chemical unit operations in the fields of drinking water preparation, industrial wastewater treatment, metal processing coatings, biological product processing, petroleum processing, etc. . However, due to membrane fouling in the industrial application of ultrafiltration membranes, the permeation flux of the membrane decreases, the membrane performance deteriorates, and the service life is shortened. [0003] As we all know, because the surface of the hydrophilic membrane can form an ordered hydrogen bond structure with water molecules, thereby reducing the adsorption behavior and adsorption a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01D71/34B01D71/68B01D71/42B01D69/02B01D67/00
Inventor 孟晓荣张海珍赵亮王磊王旭东
Owner 西安金藏膜环保科技有限公司
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