【摘要】：納濾是介于超濾與反滲透之間的一種膜分離技術(shù),在水處理、食品、制藥、化學(xué)等行業(yè)中已經(jīng)有了廣泛的應(yīng)用。耐溶劑納濾是把納濾過程引入到了有機(jī)相當(dāng)中。隨著高穩(wěn)定性、性能突出的耐溶劑納濾膜的制備開發(fā),對(duì)耐溶劑納濾膜傳質(zhì)過程的研究得到了越來越多的關(guān)注。與傳統(tǒng)的納濾過程相比,由于膜、溶劑、溶質(zhì)三元體系間復(fù)雜的相互作用,耐溶劑納濾傳質(zhì)過程比較復(fù)雜。而且對(duì)耐溶劑膜的傳質(zhì)過程研究尚不透徹,比如溶劑/溶質(zhì)透過膜的過程是靠粘性流還是擴(kuò)散,至今沒有一個(gè)定論。目前的傳遞模型有不同的缺陷,且沒有普適性比較好的模型,這無疑阻礙了耐溶劑納濾的實(shí)際應(yīng)用。因此對(duì)耐溶劑納濾傳質(zhì)機(jī)理的應(yīng)用是目前一個(gè)比較熱門的研究領(lǐng)域。本文首先研究了甲醇、乙醇、甲苯、丙酮等一系列純?nèi)軇┩ㄟ^耐溶劑納濾膜的過程,考慮到溶劑的通量與溶劑的性質(zhì)、膜的性質(zhì)關(guān)系比較大,采用相關(guān)性分析的方法對(duì)它們之間的關(guān)系進(jìn)行了分析。發(fā)現(xiàn)溶劑通量與溶劑的黏度、介電常數(shù)關(guān)系比較大,同時(shí)與溶劑/膜之間的溶解度參數(shù)差和表面張力差關(guān)系也比較大�；谶@些研究結(jié)論,建立了一個(gè)基于不完全溶解擴(kuò)散模型的半經(jīng)驗(yàn)?zāi)Ｐ?該模型的適用性在一系列溶劑中都都得到了驗(yàn)證。本文系統(tǒng)地研究了耐溶劑納濾膜用于分離二元溶劑混合物地可行性。選取了在介電常數(shù)、表面張力、Hansen溶解度參數(shù)、黏度不同的二元溶劑體系,并用單因素分析的方法來考察不同的商用耐溶劑納濾膜(MPFTM系歹、StarMemTM系列、DuraMemTM系列)對(duì)于這一系列溶劑的分離效果。發(fā)現(xiàn)DuraMemTM 150對(duì)于乙醇／正己烷體系的分離因子高達(dá)6左右,這是目前耐溶劑納濾領(lǐng)域?qū)τ谌莘e分離發(fā)現(xiàn)的最好地結(jié)果。對(duì)有分離效果的體系進(jìn)行了深入的考察,發(fā)現(xiàn)溶劑優(yōu)先通過地現(xiàn)象主要取決于膜的類型、以及膜一溶劑之間的Hans en溶解度參數(shù)差和極性差。并第一次提出了耐溶劑納濾膜用于溶劑分離的一些基本假設(shè)。本文基于傳統(tǒng)的溶解一擴(kuò)散模型,提出了一個(gè)專門用于描述耐溶劑納濾溶劑分離過程的經(jīng)驗(yàn)?zāi)Ｐ�。本模型主要包含兩個(gè)參數(shù)：Hans en溶解度參數(shù)和介電常數(shù)�？梢暂^好的用來描述一些致密性膜如DuraMemTM 150,200,300和MPF-44對(duì)二元溶劑的分離現(xiàn)象。而對(duì)于疏松膜如DuraMemTM 500 和 DuraMemTM 900的描述效果則比較差,這和該模型的假設(shè)是一致的。該模型提供了一種理解耐溶劑納濾膜用于二元溶劑分離的新思路,為該領(lǐng)域進(jìn)一步的研究工作打開了一個(gè)良好的突破口。
[Abstract]:Nanofiltration is a membrane separation technology between ultrafiltration and reverse osmosis, which has been widely used in water treatment, food, pharmaceutical, chemistry and other industries. Solvent-resistant nanofiltration is the introduction of nanofiltration processes into organic equivalents. With the preparation and development of solvent-resistant nanofiltration membranes with high stability and outstanding properties, more and more attention has been paid to the mass transfer process of solvent-resistant nanofiltration membranes. Compared with the traditional nanofiltration process, the solvent-resistant nanofiltration mass transfer process is more complex due to the complex interaction among membrane, solvent and solute ternary system. The mass transfer process of solvent-resistant membranes has not been thoroughly studied, such as whether the solvent / solute permeation process depends on viscous flow or diffusion, so far there is no final conclusion. The present transfer model has different defects, and there is no universal model, which undoubtedly hinders the practical application of solvent resistance nanofiltration. Therefore, the application of solvent resistance nanofiltration mechanism is a hot research field. In this paper, a series of pure solvents, such as methanol, ethanol, toluene, acetone and so on, have been studied. Considering the flux of solvent and the properties of solvent, the relationship between the properties of membrane and the flux of solvent is relatively large. The relationship between them was analyzed by the method of correlation analysis. It is found that the solvent flux has a great relationship with the viscosity and dielectric constant of the solvent, and also with the solubility parameter difference and the surface tension difference between the solvent and the membrane. Based on these conclusions, a semi-empirical model based on incomplete solution diffusion model is established, and its applicability is verified in a series of solvents. The feasibility of solvent-resistant nanofiltration membrane for separation of binary solvent mixtures has been systematically studied in this paper. Binary solvent systems with different dielectric constants, surface tension, Hansen solubility parameters and viscosity were selected, and different commercial solvent-resistant nanofiltration membranes (MPFTM series, StarMemTM series) were investigated by single factor analysis. DuraMemTM series) for the separation of this series of solvents. It is found that the separation factor of DuraMemTM 150 for ethanol / n-hexane system is as high as 6, which is the best result of volume separation in the field of solvent resistance nanofiltration. It is found that the preferential passage of solvent depends mainly on the type of membrane and the difference of Hans en solubility parameter and polarity between membrane and solvent. Some basic assumptions of solvent-resistant nanofiltration membrane for solvent separation were proposed for the first time. Based on the traditional solution-diffusion model, an empirical model is proposed to describe the solvent resistant nanofiltration separation process. The model consists of two parameters,: Hans en solubility parameter and dielectric constant. It can be used to describe the separation of binary solvents by some dense membranes such as DuraMemTM 150200300 and MPF-44. However, the description of loose films such as DuraMemTM 500 and DuraMemTM 900 is poor, which is consistent with the assumption of the model. The model provides a new way to understand the application of solvent-resistant nanofiltration membrane in binary solvent separation and opens a good breakthrough for further research in this field.
【學(xué)位授予單位】：北京化工大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2014
【分類號(hào)】：TQ028.8
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本文編號(hào)：2425302