本文選題：滲透蒸發(fā)膜　切入點：丙酮脫水　出處：《天津大學(xué)》2015年博士論文　論文類型：學(xué)位論文

【摘要】：滲透蒸發(fā)因其具有低能耗、投資小、不受氣液平衡限制等優(yōu)點,在有機物脫水分離領(lǐng)域具有廣闊的應(yīng)用前景。本文以丙酮和水的滲透蒸發(fā)分離為研究對象,針對高分子膜的“trade-off”效應(yīng),通過增加水在膜中的溶解性和擴散性來解決“trade-off”效應(yīng)。為了提高水在膜內(nèi)的溶解性,本文通過摻雜親水性無機顆�；蛟诟叻肿由辖又τH水性基團(tuán)來提高膜的親水性。同時為了提高水在膜中的擴散性,本文通過在膜中構(gòu)建無機通道,為水的擴散提供高選擇性的連續(xù)通道,強化水傳遞過程;或?qū)⑺肿印盎罨?即將大水分子簇變成小水分子簇,增加水分子的滲透性和擴散性,提高水通量。主要研究結(jié)果如下:首先,將親水性鉀型蒙脫土(K+MMT)摻雜到殼聚糖(CS)膜中,在膜中構(gòu)建離子化水通道。利用K+MMT層間K+的水溶劑化效應(yīng),來提高膜對水的選擇性,同時層狀的K+MMT為水分子提供連續(xù)的傳遞通道并增大了聚合物鏈間距,強化水的傳遞。CS-K+MMT-10雜化膜在50oC、水含量為5wt.%時,滲透通量為1.56kg/m2h,分離因子為2200,比純殼聚糖膜分離因子(249),提高了約8倍。其次,將疏水性多孔碳分子篩經(jīng)過磺化接枝高親水性磺酸根,然后將磺化碳分子篩(SCMS)摻入CS膜中,在膜中構(gòu)建具有親水位點的疏水通道。利用SCMS上磺酸根的親水性提高水選擇性,利用通道的疏水性降低水分子傳遞的能量壁壘,提高水通量。CS-SCMS-2雜化膜在50oC水含量為5wt.%時滲透通量為1.81kg/m2h,分離因子為832,與純殼聚糖膜相比,通量和分離因子分別提高1.67倍和2倍。再次,利用強電解質(zhì)在水中可完全電離,與弱電解質(zhì)相比能和更多的水分子形成水合離子的性質(zhì),將CS中弱堿性的氨基改性成強堿性的胍基,合成殼聚糖胍(CG)。胍基通過誘導(dǎo)極化與更多的水分子形成水化層,提高水選擇性;同時,利用胍基的“結(jié)構(gòu)碎化”效應(yīng)(“Structure breaking”effect),使大水分子簇變成小水分子簇,增強水分子的滲透性,強化水的傳遞。結(jié)果表明CG-50-pH2.5-1:2膜內(nèi)胍基取代度為8.69%,在50oC、水含量為5wt.%時,其滲透通量可以達(dá)到1.9kg/m2h,分離因子為3300,比純殼聚糖膜分別提高1.26倍和13倍。最后,選用氨基含量更高的聚乙烯胺(PVAm)為膜材料,采用類似的方法,將PVAm中的氨基改性成胍基,合成了聚乙烯胍(PVG)。隨著胍基取代度的增加,膜的水接觸角減小,親水性增強。PVG-50-pH2-1:2膜內(nèi)胍基取代度為18.41%,在50oC、水含量為5wt.%時,通量為2.32kg/m2h,分離因子為3781,性能高于殼聚糖胍膜。
[Abstract]:Because of its advantages of low energy consumption, low investment and no restriction of gas-liquid equilibrium, osmotic evaporation has a broad application prospect in the field of dehydration of organic compounds. In this paper, the separation of acetone and water by pervaporation is studied. In view of the "trade-off" effect of polymer membrane, the "trade-off" effect is solved by increasing the solubility and diffusibility of water in the membrane. In this paper, the hydrophilicity of the membrane was improved by doping hydrophilic inorganic particles or grafting hydrophilic groups on the polymer, and in order to improve the diffusion of water in the membrane, inorganic channels were constructed in this paper. Providing highly selective continuous channels for water diffusion to enhance the water transfer process, or "activating" water molecules, that is, changing large water molecules into small water molecules, thus increasing the permeability and diffusion of water molecules. The main results are as follows: firstly, the hydrophilic potassium montmorillonite (K MMT) was doped into the chitosan (CS) membrane, and an ionization water channel was constructed in the membrane. The water selectivity of the membrane was improved by using the water solvation effect of K between K MMT layers. At the same time, the layered K MMT provides a continuous transfer channel for water molecules and increases the polymer chain spacing. When the water transfer. CS-K MMT-10 hybrid film is 50oC, the water content is 5wt.%. The permeation flux was 1.56 kg 路m ~ (-2) h and the separation factor was 2200, which was about 8 times higher than that of pure chitosan membrane separation factor (249N). Secondly, the hydrophobic porous carbon molecular sieve was sulfonated onto high hydrophilic sulfonic acid radical, and then the sulfonated carbon molecular sieve (SCMS) was doped into CS membrane. Hydrophobic channels with hydrophilic sites were constructed in the membranes. The hydrophilicity of sulfonic acid on SCMS was used to improve the hydrophobicity, and the hydrophobicity of channels was used to reduce the energy barrier of water transfer. When the water flux. CS-SCMS-2 hybrid membrane was 50 鈩，

本文編號：1617342