反渗透集成真空膜蒸馏浓缩中药水提液的膜传质过程研究

发布时间：2018-01-08 18:29

本文关键词：反渗透集成真空膜蒸馏浓缩中药水提液的膜传质过程研究　出处：《南京中医药大学》2017年硕士论文　论文类型：学位论文

【摘要】：反渗透(RO)技术近年来已逐渐用于中药领域,其操作温度较低,能充分保护热敏性有效成分不受破坏,但浓缩倍数较小。真空膜蒸馏(VMD)技术具有操作简便、有效成分损失小、高浓缩比等优点,可有效弥补传统浓缩方法的不足,但与工业应用要求距离尚远。除了膜污染这一共性问题外,各种膜浓缩过程因其技术原理而造成的缺陷,也影响到它们优势的发挥。因此本论文将RO-VMD集成技术用于中药水提液的浓缩,研究其过程中流变学参数与膜动力参数的相关性,并且针对VMD过程的阂值通量、RO过程的临界渗透压来优化膜工艺,以不同药用部位的中药水提液主要实验体系,进行了 RO-VMD集成切换"临界点"研究,并对RO-VMD集成过程进行评价;优化RO与VMD的耦合过程,对中药提取液的有效浓缩实现过程控制具有现实意义。本论文主要研究内容与结果如下:1以蒲公英、槐米等4种中药水提液为研究体系,进行RO-VMD集成初步研究,药液在进入反渗透系统(0.45 MPa,30℃)200 min后,大多数药液渗透压都已超过外加压力,即反渗透过程驱动压力已降为0MPa,膜过程应当难以继续,否则会对膜组件有较大伤害。当药液渗透压出现平衡值时,膜过程驱动压力也刚好为0MPa,是所要寻找的最佳平衡点,因此对膜蒸馏、反渗透过程需要进一步的探讨适宜的浓缩工艺参数。2以莱菔子水提液为研究对象,以压力递增实验确定了VMD过程中的阈值通量以及极限通量,分析了不同条件下的通量衰减、阻力、TPC值以及膜表面的SEM图,当在极限通量下时,运行180min后膜通量降低了 15.4%,而在阈值通量下,膜通量只降低了 1.63%,且10min内通量几乎稳定,表明可逆污染层形成非常迅速,且极限通量下的膜阻力是阈值通量的2.5倍,增加能耗。因此,在阈值通量下运行可避免严重的通量衰减,也比较节能,且更适合于长时间运行,实现在某操作条件下,可逆污染可能无法避免的情况下达到不可逆污染的最小化,证明了阈值通量对更好地设计膜过程,延长膜寿命有重要的作用。3选择不同药用部位的其他6种中药水提液,研究真空膜蒸馏过程中的阈值通量,分析药液的物理化学性质与阈值线(K值)以及阈值点(真空度、阈值通量)之间的相关性。随着浓度增大,阈值点会前移,由于不可逆污染的提前发生。通过Pearson相关系数和聚类分析结果可知,药液的密度、黏度和粒径分布对阂值线以及阈值点的影响较大,其中,密度正相关,黏度和粒径负相关。4综合分析RO-VMD集成过程对于中药水提液浓缩的适应性,以及不同中药水提液过膜前后理化性质的变化。由测定结果可知,浓缩前后理化参数均发生变化,pH值变化幅度较小,而电导率、浊度、粘度、固含物含量均大幅度增加,与浓缩过程中药液的浓度增大存在密切关系。膜集成过程对各药液指标性成分的截留率均在93%以上,且通过中药水提液浓缩前后的液相特征图谱分析,各中药的浓缩液与原液的相似度均大于0.93,说明RO-VMD集成浓缩过程对药液总体性质影响不大,可以很好地维持药液体系可能的药效成分组的完整性。综上,本论文从实际应用问题出发,在研究VMD过程中引入阈值通量的概念,为探索合适的膜工艺过程设计提供基础研究数据,以减少膜污染并提高膜分离浓缩效率。将反渗透以及膜蒸馏技术进行集成以探索其对于中药水提液浓缩的适应性,具有原创性。
[Abstract]:Reverse osmosis (RO) technology in recent years has been gradually used in the field of traditional Chinese medicine, its operating temperature is low, can fully protect the labile compounds from destruction, but the concentration is small. The vacuum membrane distillation (VMD) technology has the advantages of simple operation, small loss of effective components, high concentration ratio and other advantages, can effectively make up for the shortcomings of traditional concentration method but, with the requirements of industrial application range is still far away. In addition to the common problem of membrane fouling, membrane defect concentration process because of its technical principle and cause, also affect their advantages. So this paper will integrate RO-VMD technology for water extract concentration, correlation between the parameters and dynamic rheological parameters of membrane the learning process, and the value for the VMD flux process threshold, to optimize the membrane process pressure critical infiltration RO process, the water extracts of different parts of the main experimental system, the RO-VMD integrated switch" The critical point of research, and to evaluate the RO-VMD integration process; coupling process optimization of RO and VMD, the effective concentration extraction process has practical significance. The main contents and results are as follows: 1 to 4 kinds of dandelion, Flos Sophorae herb extracts as the research system, RO-VMD preliminary study integrated liquid in the reverse osmosis system (0.45 MPa, 30 C) after 200 min, most liquid osmotic pressure applied pressure has exceeded, namely reverse osmosis process driven pressure has been reduced to 0MPa, membrane processes should be difficult to continue, otherwise there will be greater damage to the membrane. When the liquid osmotic pressure balance value. Just as the pressure driven membrane process 0MPa, is to find the best balance point, so the membrane distillation, reverse osmosis process need to concentrate process parameters of.2 suitable to Raphani extract as the research object in order to further increase the pressure. In the process of the experiment to determine the VMD threshold limit flux and flux analysis under different conditions of flux decay resistance, TPC value and SEM diagram of the membrane surface, when the flux in the limit when running the 180min membrane flux decreased by 15.4%, while in the threshold flux, the flux only decreased by 1.63%, and 10min flux is almost stable, show that the reversible fouling layer formed very rapidly, and the limit flux of membrane resistance is 2.5 times the threshold flux increases energy consumption. Therefore, to avoid severe flux decline runs in the threshold flux, but also more energy, and more suitable for long time operation, to achieve in a certain operating conditions reversible pollution may not be able to avoid the case to minimize irreversible pollution, proved that the threshold flux on the better design of membrane process, prolong the service life of the membrane has an important role for.3 in different medicinal parts of other 6 kinds of Chinese medicinal herbs extract, research The threshold flux of vacuum membrane distillation process, analysis of physical and chemical properties of the liquid and the threshold line (K) and threshold (vacuum, threshold flux) correlation. With the increase of the concentration, the threshold point will move forward because of the irreversible pollution occur in advance. Through the Pearson correlation coefficient and cluster analysis results, liquid the density, viscosity and particle size distribution of threshold value and threshold point line effect is large, the density of positive correlation, negative correlation between.4 viscosity and particle size analysis of RO-VMD integrated process for water extract concentrated adaptability to changes before and after the water extract of Chinese herbs and different membrane physicochemical properties by the determination. Results showed that the concentration before and after the physicochemical parameters are changed, the pH value changed little, while the electrical conductivity, turbidity, viscosity, solid content were greatly increased, high concentration has a close relationship with the Chinese medicine liquid concentration process of membrane set increased. A rate of more than 93% of the retention index of component liquid, and the water extract concentrated liquid phase fingerprint analysis and similarity, concentrated liquid and liquid the medicine was greater than 0.93, indicating that RO-VMD integrated concentration process has little effect on the overall properties of the liquid, can well maintain the integrity of the liquid the system may pharmaceutical components group. In conclusion, this thesis is from the practical problems, introduce the concept of threshold flux in VMD process, provide basic data for the exploration of film process design appropriate, to reduce membrane fouling and improve membrane separation efficiency. The concentration of reverse osmosis and membrane distillation technology integrated with to explore the originality for water extract concentrated adaptability.

【学位授予单位】：南京中医药大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TQ461;TQ028.8

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