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  本文關鍵詞： 超支化聚硅氧烷 滲透汽化 多層復合膜 2 3-丁二醇 正丁醇　出處：《江南大學》2015年碩士論文　論文類型：學位論文

【摘要】：低分子醇如正丁醇,2,3-丁二醇作為可再生生物燃料及重要化學前軀體,皆可由發(fā)酵法制備,如何經濟有效地分離低分子醇具有重要的意義。滲透汽化分離液體混合物具有能耗低,對環(huán)境污染小,操作簡單等特點,廣泛應用于有機物脫水,水中有機物分離及有機混合物分離。在研究新型的滲透汽化膜的過程中,超支化聚合物相比于傳統(tǒng)線性聚合物,其分子含有大量末端官能團,具有分子纏繞少,反應活性高,流變性能優(yōu)異,自由體積大等優(yōu)點,受到了廣泛關注。超支化聚合物應用于滲透汽化膜一般具有較高的通量,但是主要應用于滲透汽化有機物脫水和有機混合物分離,而將超支化聚合物應用于滲透汽化分離水中有機物的研究較少。本文在超支化聚硅氧烷的基礎上,深入研究制備新型超支化聚合物膜用于滲透汽化分離水中低分子醇。本文基于超支化聚硅氧烷高度支化的分子結構,分別制備了以超支化聚硅氧烷膜為支撐層和分離層的滲透汽化復合膜用于分離水中正丁醇,同時研究了滲透汽化與萃取耦合分離提純水中2,3-丁二醇,其主要實驗內容為:(一)通過AB2型單體一步法合成了超支化聚硅氧烷(HPSi O),并以HPSi O-c-PDMS-1為中間層,VTES-c-PDMS為表層分離層制備了具有多層結構的復合膜;(二)制備了不同HPSi O含量的HPSi O-c-PDMS-3復合膜;對上述復合膜膜形態(tài)及性能進行分析,并對其用于滲透汽化分離水中正丁醇進行研究。(三)通過萃取法繪制2,3-丁二醇/水/正丁醇的三元相圖,將所選萃取相先后通過PVA膜及HPSi O-c-PDMS-2膜長時間滲透汽化分離,測定滲余液中2,3-丁二醇濃度判斷是否達到分離提純2,3-丁二醇的目的。其實驗結果表明:(1)合成了較高支化度的超支化聚硅氧烷,復合膜為具有明顯多層結構的超支化滲透汽化膜。隨著選擇層VTES-c-PDMS層中PDMS分子量的增加,膜的滲透通量降低,對丁醇和水的滲透性降低,而分離因子和選擇性增加。其中,FHPV-3多層復合膜的通量為450g/(m2h),分離因子為28。隨著料液溫度的增加,多層復合膜的通量及分離因子均呈上升趨勢;隨著料液濃度的增加,多層復合膜的通量上升而分離因子變化較小,通過滲透液濃度可知,當原料液濃度為2.5wt%時,透過液濃度為42wt%,滲透效果提升明顯。(2)HPSi O-c-PDMS-3復合膜中,當HPSi O含量低于50wt%時,HPSi O以球狀形式分布于有機膜基質中,當HPSi O含量高于50wt%時,HPSi O以鏈狀形式分布于有機膜基質中。HPSi O含量的增加,膜的疏水性下降,其滲透汽化對丁醇滲透性降低,膜選擇性下降,而滲透通量上升。當HPSi O含量為37.5wt%時,膜的通量為229.85g/(m2h),分離因子為39.5,其滲透通量達到最大。HPSi O在膜基質中的分布形式不影響滲透汽化膜隨料液溫度,料液濃度變化的趨勢。(3)通過溶液萃取法,繪制了24oC下2,3-丁二醇/正丁醇/水的三元相圖。通過PVA膜及HPSi O-c-PDMS-2膜滲透汽化性能隨溫度的變化確定PVA膜的連續(xù)化操作溫度為40oC,HPSi O-c-PDMS-2膜連續(xù)化操作溫度為50oC~60oC。PVA膜滲透汽化時間達10h時,滲余液中水的質量濃度從31.27wt%下降到10.85wt%,2,3-丁二醇的質量濃度從10.56wt%上升到14.09wt%;隨著HPSi O-c-PDMS-2膜滲透汽化時間達48h時,滲余液中2,3-丁二醇的質量濃度達到69.41wt%。
[Abstract]:Low molecular weight alcohols such as butanol, 2,3- butanediol as renewable biofuels and chemical precursors can be prepared by fermentation, how to effectively separate low molecular weight alcohols has important significance. The pervaporation separation of liquid mixtures with low energy consumption, little environmental pollution, simple operation and other characteristics, widely used in organic matter dehydration, separation of Organics in water and organic mixture separation. In the process of pervaporation membrane model in hyperbranched polymers compared with traditional linear polymers, the molecules of which contain a large number of terminal groups, with molecular winding less, high reaction activity, excellent rheological properties, the advantages of the free volume is large, hyperbranched has attracted widespread attention. The polymer used in pervaporation membrane with high flux, but mainly used in pervaporation dehydration of organic and organic mixture separation, the hyperbranched polymer should be For the study of pervaporation separation of organics in the water less. Based on hyperbranched polysiloxane, in-depth study of preparation of novel hyperbranched polymer membrane for pervaporation separation of water ethanol. The low molecular weight hyperbranched polysiloxane highly branched molecular structure based on respectively prepared by Hyperbranched polysiloxane membrane for pervaporation composite membrane support layer and separation layer for the separation of water and n-butanol on the permeation and separation and purification of water extraction of PVMR 2,3- butanediol, its main experiments: (a) by AB2 single step synthesis of hyperbranched polysiloxane (HPSi O), and HPSi O-c-PDMS-1 as the middle layer, VTES-c-PDMS the surface separation composite film has a multilayer structure prepared by layer; (two) HPSi O-c-PDMS-3 HPSi composite films with different O content were prepared; the composite membrane morphology and properties were analyzed, And the water for the pervaporation separation of n-butanol were studied. (three) by extraction method to draw 2,3- butylene glycol / water / three phase diagram of n-butanol, the selected extraction phase has passed PVA membrane and HPSi membrane O-c-PDMS-2 long time pervaporation separation, determination of whether the infiltration of 2,3- butanediol concentration in the raffinate to judge purification of 2,3- butanediol to separation. The experimental results show that: (1) high degree of branching hyperbranched polysiloxane were synthesized. The composite film has obvious multilayer structure of hyperbranched pervaporation membrane. With the increase of PDMS selection molecular layers of VTES-c-PDMS amount, the permeate flux decreased and the permeability of butanol and water the lower, while the separation factor and selectivity increased. Among them, FHPV-3 multilayer composite membrane flux is 450g/ (m2h), the separation factor is 28. with the increase of feed temperature, the flux and separation factor of multilayer films increased with; With the increase of feed concentration, multilayer composite membrane flux increases the separation factor of small changes, the permeate concentration shows that when the feed concentration is 2.5wt%, the liquid concentration is 42wt%, significantly enhance the penetration effect. (2) HPSi O-c-PDMS-3 composite film, when the HPSi O content is lower than 50wt%, HPSi to O the globular form distributed in the organic membrane matrix, when the HPSi content of O was higher than 50wt%, increased HPSi O chain in the form of distribution in the.HPSi O content of organic membrane matrix, hydrophobic membrane decreased, the pervaporation of butanol permeability decreased, membrane selectivity decreased, while the permeation flux increased when the HPSi content is O. 37.5wt%, the membrane flux is 229.85g/ (m2h), the separation factor was 39.5, distribution of the permeation flux reaches the maximum at.HPSi O in the membrane matrix does not affect the pervaporation membrane with the feed temperature, feed concentration change trend. (3) by solvent extraction, drawing 24oC 2,3- butanediol / n-butanol / water three phase diagram by PVA. O-c-PDMS-2 membrane and HPSi membrane pervaporation performance changes with temperature to determine the continuous operating temperature of PVA film is 40oC, HPSi O-c-PDMS-2 film continuous operation temperature of 50oC~60oC.PVA membrane pervaporation time was 10h, the concentration of residual liquid water infiltration decreased from 31.27wt% to 10.85wt%, the mass concentration of 2,3- butanediol increased from 10.56wt% to 14.09wt%; HPSi with O-c-PDMS-2 membrane pervaporation time was 48h, the concentration of infiltration in the raffinate of 2,3- butanediol reached 69.41wt%.

【學位授予單位】：江南大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TQ051.893

【參考文獻】

相關期刊論文 前2條

1 白云翔;朱元華;張春芳;顧瑾;孫余憑;;高通量超支化聚硅氧烷復合膜滲透汽化分離水中正丁醇[J];膜科學與技術;2013年03期

2 劉公平;侯丹;衛(wèi)旺;相里粉娟;金萬勤;;PDMS/陶瓷復合膜用于正丁醇-水體系的滲透汽化分離(英文)[J];Chinese Journal of Chemical Engineering;2011年01期

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本文編號：1518862