【摘要】：本文用聚丙烯中空纖維膜為基材,在其表面涂覆一層多孔的超疏水涂層,將聚丙烯中空纖維膜改性為超疏水中空纖維膜。本文旨在尋找一種成本低廉,操作簡(jiǎn)單可行的方法來(lái)制備超疏水聚丙烯中空纖維膜。利用APS/TEOS的不同比例,制備出不同尺寸的二氧化硅顆粒。并通過(guò)透射電子顯微鏡(TEM)觀察其粒徑大小。然后將聚丙烯顆粒加入到二甲苯溶液中溶解后,加入二氧化硅顆粒用溶膠-凝膠法制得溶膠,加入非溶劑2-丁酮,在相分離的作用下,將溶膠涂覆與聚丙烯中空纖維膜的表面。利用聚丙烯溶液在表面形成的網(wǎng)狀結(jié)構(gòu),將二氧化硅顆粒附著于膜的表面,以此來(lái)增加膜的表面粗糙度。最后用1H,1H,2H,2H-全氟辛基三乙氧基硅烷(POTS)修飾涂覆后的聚丙烯中空纖維膜,進(jìn)過(guò)修飾后的聚丙烯中空纖維膜的表面自由能降低,然后得到接觸角為158°的超疏水聚丙烯中空纖維膜。對(duì)改性后的聚丙烯中空纖維膜進(jìn)行掃描電鏡(SEM)和原子力顯微鏡的(AFM)測(cè)試觀察,發(fā)現(xiàn)膜表面的涂層為多孔連續(xù)的涂層,并且相比較原膜,改性后的膜表面的粗糙度有了很大的提高。通過(guò)XPS和傅里葉紅外光譜(FT-IR)的測(cè)試,發(fā)現(xiàn)POTS和二氧化硅成功的接枝在膜表面,有效的增加了粗糙度和降低了表面能。同時(shí),討論了二氧化硅顆粒的用量、聚丙烯顆粒用量、涂覆次數(shù)、MEK用量等方面對(duì)聚丙烯中空纖維膜的超疏水性能影響,從而確定在聚丙烯中空纖維膜超疏水改性的最佳條件。對(duì)改性后的超疏水聚丙烯中空纖維膜進(jìn)行膜蒸餾的實(shí)驗(yàn)。利用壓汞法測(cè)定改性后超疏水聚丙烯中空纖維膜的平均孔徑和孔隙率。改性后膜的平均孔徑有所下降,孔隙率較原膜相比,有所提高,說(shuō)明超疏水涂層是多孔的。測(cè)定不同改性膜在3.5wt%NaCl溶液中的通量和截留率,得出改性后膜通量較原膜有所上升,同時(shí)截留率提高到99.9%。并且研究討論了 NaCl溶液溫度、NaCl溶液濃度、真空度等條件變化對(duì)改性超疏水聚丙烯中空纖維膜在膜蒸餾中的通量和截留率的變化。
[Abstract]:In this paper, polypropylene hollow fiber membrane was modified into super hydrophobic hollow fiber membrane by coating a porous superhydrophobic coating on its surface. The purpose of this paper is to find a cheap, simple and feasible method to prepare superhydrophobic polypropylene hollow fiber membrane. Silica particles of different sizes were prepared by using different proportion of APS/TEOS. The particle size was observed by transmission electron microscope (TEM). Then the polypropylene particles were dissolved in xylene solution and silica particles were prepared by sol-gel method. The sols were coated on the surface of polypropylene hollow fiber membrane under the action of phase separation by adding non-solvent 2-butanone. In order to increase the surface roughness of the film, silica particles are attached to the surface of the film by using the network structure formed on the surface of the polypropylene solution. Finally, the polypropylene hollow fiber membrane coated with 1H ~ 1H ~ (-1) H _ (2) H _ (2) H _ (2) H _ (2) H _ (2) H _ (2) fluorooctyl triethoxysilane (POTS) was modified. The surface free energy of the modified polypropylene hollow fiber membrane was decreased, and then the super hydrophobic polypropylene hollow fiber membrane with a contact angle of 158 擄was obtained. Scanning electron microscope (SEM) and atomic force microscopy (AFM) were used to test the modified polypropylene hollow fiber membrane. It was found that the coating on the membrane surface was porous and continuous, and compared with the original membrane. The surface roughness of the modified film has been greatly improved. The results of XPS and Fourier transform infrared spectroscopy (FT-IR) show that POTS and silica are grafted on the surface of the film effectively increasing the roughness and reducing the surface energy. At the same time, the effects of the amount of silica particles, the amount of polypropylene particles and the amount of MEK coating on the superhydrophobicity of polypropylene hollow fiber membrane were discussed, and the optimum conditions for superhydrophobic modification of polypropylene hollow fiber membrane were determined. The membrane distillation of modified superhydrophobic polypropylene hollow fiber membrane was carried out. The average pore size and porosity of modified superhydrophobic polypropylene hollow fiber membrane were measured by mercury injection method. The average pore size of the modified membrane was decreased, and the porosity was increased compared with that of the original membrane, indicating that the superhydrophobic coating is porous. The flux and retention rate of different modified membranes in 3.5wt%NaCl solution were measured. The results showed that the flux of the modified membrane was higher than that of the original membrane, and the retention rate was increased to 99.9%. The flux and retention of modified superhydrophobic polypropylene hollow fiber membrane in membrane distillation were studied.
【學(xué)位授予單位】：天津工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2017
【分類號(hào)】：TQ051.893

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本文編號(hào)：2180621