阅读说明：本技术 改性超滤膜及其改性方法 (Modified ultrafiltration membrane and modification method thereof ) 是由 陈泉学 于 2019-08-28 设计创作，主要内容包括：本发明提出了一种改性超滤膜及其改性方法,改性超滤膜主要包括聚砜、磺化聚砜、表面活性剂和溶剂,改性方法通过制备铸膜液,将铸膜液进行刮膜和湿法凝固得到平板超滤膜,再利用反应型表面活性剂和紫外光照射活化以及改性溶液的接枝改性达到对超滤膜进行表面改性的目的,本发明的改性超滤膜具有良好的机械强度,同时其亲水能力强,能够有效防止有机物污染,在长期使用过程中仍然能够保持较高的水通量,具有良好的应用前景。(The invention provides a modified ultrafiltration membrane and a modification method thereof, wherein the modified ultrafiltration membrane mainly comprises polysulfone, sulfonated polysulfone, a surfactant and a solvent, the modification method is characterized in that a membrane casting solution is prepared, the membrane casting solution is subjected to membrane scraping and wet solidification to obtain a flat ultrafiltration membrane, and the purpose of surface modification of the ultrafiltration membrane is achieved by utilizing reactive surfactant and ultraviolet irradiation activation and graft modification of a modification solution.)

1. A modification method of a modified ultrafiltration membrane is characterized by comprising the following steps:

Step one, mixing raw materials of the membrane casting solution, stirring for dissolving, performing microporous filtration after dissolving, and standing for defoaming under the condition of vacuum constant temperature to obtain the membrane casting solution;

Step two, uniformly coating the membrane casting solution obtained in the step one on non-woven fabrics, carrying out membrane scraping forming through a flat membrane scraping machine, evaporating for 1-2min at normal temperature and normal pressure after membrane scraping, and then solidifying and forming a membrane through a dry-wet phase transition method to obtain a flat ultrafiltration membrane;

Step three, soaking the flat ultrafiltration membrane prepared in the step two in a surfactant solution, and performing activation treatment on the flat ultrafiltration membrane under the ultraviolet irradiation condition for 5-10 min;

Step four, putting the activated flat ultrafiltration membrane into the modified solution, stirring and adsorbing for 0.5-1h to obtain a graft modified flat ultrafiltration membrane;

And step five, soaking the grafting modified flat ultrafiltration membrane in pure water, and removing the residual surfactant and the modification solution.

2. The method for modifying the modified ultrafiltration membrane according to claim 1, wherein in the first step, raw materials of the mixed membrane casting solution comprise the following raw materials in parts by weight:

3. The method for modifying a modified ultrafiltration membrane of claim 2, wherein the weight average molecular weight of the polysulfone is 5-8 kilodaltons, the weight average molecular weight of the sulfonated polysulfone is 2-3 kilodaltons, and the sulfonation degree of the sulfonated polysulfone is 20-40%.

4. The method of claim 2, wherein the surfactant is one of tween 20, tween 80, polyoxyethylene octylphenol ether, octylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether and sodium dodecylsulfate.

5. The method of claim 2, wherein the solvent is one of N, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.

6. the method for modifying a modified ultrafiltration membrane of claim 1, wherein said surfactant solution in step three is a reactive surfactant solution.

7. the method for modifying a modified ultrafiltration membrane of claim 6, wherein the surfactant solution is an aqueous solution of methacryloyloxyethyl alkyl dimethyl ammonium bromide, and the mass concentration of the solution is 15-30%.

8. the method for modifying a modified ultrafiltration membrane of claim 1, wherein in step four, the modifying solution is an aqueous solution of carboxymethyl chitosan.

9. The method for modifying a modified ultrafiltration membrane according to claim 8, wherein the mass concentration of the aqueous solution of carboxymethyl chitosan is 15 to 20%.

10. A modified ultrafiltration membrane, which is modified by the method for modifying a modified ultrafiltration membrane according to any one of claims 1 to 9.

Technical Field

The invention relates to the technical field of sewage treatment equipment, in particular to a modified ultrafiltration membrane and a modification method thereof.

Background

ultrafiltration is an efficient separation technology, has good effect on removing colloids, bacteria, viruses and various organic matters in water, and has the advantages of simple operation steps, easy process implementation and the like compared with the traditional separation technology, so the ultrafiltration technology is widely applied to the life of people, especially the field of sewage treatment.

however, the ultrafiltration membrane is mostly made of high molecular organic materials, and the ultrafiltration membrane shows strong hydrophobicity under the condition of high mechanical strength, so that a specific adsorption effect is very easy to occur in the sewage treatment process, especially a high adsorption effect on organic matters in sewage is achieved, in the long-time treatment process, organic pollution can cause the separation performance of the ultrafiltration membrane to be greatly reduced, the sewage treatment capacity is reduced along with the separation performance, and finally the service life of the ultrafiltration membrane is greatly shortened.

At present, the approach for improving the anti-pollution capability of the ultrafiltration membrane is mainly to improve the hydrophilicity of the ultrafiltration membrane through hydrophilic modification so as to reduce the adsorption of organic pollution, the common hydrophilic modification method mainly comprises blending modification and grafting modification, neither modification method can fundamentally solve the problem of poor hydrophilicity, and other properties of the membrane can be reduced while the hydrophilicity is improved through modification.

Disclosure of Invention

In view of the above, the present invention provides a modified ultrafiltration membrane and a modification method thereof, which can stably improve hydrophilicity and ensure good mechanical properties and impact resistance.

The technical scheme of the invention is realized as follows: the invention provides a modification method of a modified ultrafiltration membrane, which comprises the following steps:

step one, mixing raw materials of the membrane casting solution, stirring for dissolving, performing microporous filtration after dissolving, and standing for defoaming under the condition of vacuum constant temperature to obtain the membrane casting solution;

step two, uniformly coating the membrane casting solution obtained in the step one on non-woven fabrics, carrying out membrane scraping forming through a flat membrane scraping machine, evaporating for 1-2min at normal temperature and normal pressure after membrane scraping, and then solidifying and forming a membrane through a dry-wet phase transition method to obtain a flat ultrafiltration membrane;

Step three, soaking the flat ultrafiltration membrane prepared in the step two in a surfactant solution, and performing activation treatment on the flat ultrafiltration membrane under the ultraviolet irradiation condition for 5-10 min;

step four, putting the activated flat ultrafiltration membrane into the modified solution, stirring and adsorbing for 0.5-1h to obtain a graft modified flat ultrafiltration membrane;

and step five, soaking the grafting modified flat ultrafiltration membrane in pure water, and removing the residual surfactant and the modification solution.

On the basis of the above technical solution, preferably, in the step one, the raw materials of the mixed casting solution include the following raw materials in parts by weight:

on the basis of the technical scheme, preferably, the weight average molecular weight of the polysulfone is 5-8 ten thousand daltons, the weight average molecular weight of the sulfonated polysulfone is 2-3 ten thousand daltons, and the sulfonation degree of the sulfonated polysulfone is 20-40%.

On the basis of the technical scheme, preferably, the surfactant is one of tween 20, tween 80, polyoxyethylene octylphenol ether, octylphenol polyoxyethylene ether, fatty alcohol polyoxyethylene ether and sodium dodecyl sulfate.

still more preferably, the solvent is one of N, N-dimethylformamide, N-dimethylacetamide and N-methylpyrrolidone.

on the basis of the above technical solution, preferably, the surfactant solution in step three is a reactive surfactant solution.

On the basis of the technical scheme, preferably, the surfactant solution is an aqueous solution of methacryloyloxyethyl alkyl dimethyl ammonium bromide, and the mass concentration of the solution is 15-30%.

On the basis of the above technical scheme, preferably, in the fourth step, the modification solution is an aqueous solution of carboxymethyl chitosan.

On the basis of the technical scheme, the preferable mass concentration of the carboxymethyl chitosan aqueous solution is 15-20%.

The invention also provides a modified ultrafiltration membrane prepared by the modification method.

compared with the prior art, the modified ultrafiltration membrane and the modification method thereof have the following beneficial effects:

(1) the modified ultrafiltration membrane of the invention adopts polysulfone and sulfonated polysulfone as main membrane materials, wherein polysulfone is hydrophobic material, sulfonated polysulfone has certain hydrophilicity, the hydrophilicity problem is improved on the raw materials, and the sulfonated polysulfone and polysulfone have similar structures, the mechanical strength of the polysulfone membrane materials is kept, secondly, the invention adopts reactive surfactant to carry out activation reaction with the ultrafiltration membrane in the preparation process, the surface of the ultrafiltration membrane of the invention carries out grafting reaction to a certain degree by ultraviolet irradiation, the hydrophilicity of the surfactant is utilized to further enhance the hydrophilicity of the surface of the ultrafiltration membrane, simultaneously, the grafting stability is high, the ultrafiltration membrane has longer service life and better use effect, the ultrafiltration membrane after ultraviolet irradiation has higher reaction activity, and is reacted with carboxymethyl chitosan solution again after ultraviolet irradiation, the surfactant grafted in the previous step is utilized to carry out grafting reaction with the ultrafiltration membrane again, and the discovery shows that the ultrafiltration membrane grafted with the carboxymethyl chitosan not only has good hydrophilicity, but also has certain antibacterial property, and provides larger steric hindrance, so that organic pollutants can be effectively prevented from penetrating through the ultrafiltration membrane, and meanwhile, the aggregation of the organic pollutants can be prevented, and a certain self-cleaning effect is achieved;

(2) the modification method of the ultrafiltration membrane is simple and effective, the modified ultrafiltration membrane obtained by modification has good hydrophilicity, and organic pollutants can be effectively prevented from being gathered on the surface of the ultrafiltration membrane in the long-term working process, so that the ultrafiltration membrane has good pollution resistance;

(3) The ultrafiltration membrane modification method is different from conventional grafting modification and blending modification, can improve the hydrophilic performance of the membrane surface while maintaining good mechanical strength, reduces organic pollution, and has good application prospect.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention.