Study On Optimization Of Membrane Process Of Traditional Chinese Medicine Volatile Oil-bearing Water Bodies By Demulsification Of Inorganic Salt

By investigating physical and chemical parameters, medicament portions and plant resources of Traditional Chinese Medicine volatile oil (TCM volatile oil), selecting a representative sample of 12 herbs essential oil, with referencing to the simulation systems, according to content of TCM volatile oil in their oil-bearing water bodies to build simulation systems, which would be used as experimental subjects, to study on optimization of membrane process of TCM volatile oil-bearing water bodies by demulsification of inorganic salt, and determining the best condition of salt before membrane separation, to provide new ideas for increasing membrane flux and oil retention rate, and reducing membrane fouling, and the basis for establishment of efficient collection technology of TCM volatile oil.First, demulsificating oil-bearing water simulation systems of TCM volatile oil before membrane separation, with different types and addition of salts, comparing membrane flux and oil retention rate, then determining the best condition of salt. The results show that adding salt can increase membrane flux of TCM volatile oil-bearing water bodies, and most sample's oil retention rate; the best salt for oil-bearing water bodies of Cortex Cinnamomi Cassiae, Herba Moslae Chinensis, Fructus Anisi Stellati, Flos Magnoliae Biondii Immaturus, Rhizoma et Radix Notopterygii, Fructus Cnidii, Rhizoma Cyperi and Semen Myristicae are sodium chloride, and that of Platycladus orientalis is potassium chloride, that of Fructus Citri Reticulatae Immaturus is magnesium chloride, and that of Rhizoma Acori Tatarinowii is sodium sulfate, their optimum dosage is 5 grams, which is equivalent to the amount of oil-bearing water body's 2%, the best salt for oil-bearing water body of Radix Angelicae Sinensis is magnesium chloride, its optimum dosage is 1 gram, which is equivalent to the amount of oil-bearing water body's 0.4%.Second, by observing changes of appearances, microscopic characteristics, physical and chemical parameters and particle sizes distribution of TCM volatile oil-bearing water bodies before and after adding salt, exploring their changes in physical and chemical properties. The results are that:(1) From the macro perspective, the oil-bearing water bodies are uniformly, cloudy, milky and white before adding salt, then change to clarify after adding salt, and oil is floating on the surface, slightly demixing from water layer; (2) From the micro perspective, the number of oil drops in oil-bearing water bodies are decreasing after adding salt; (3)From the analysis of physical and chemical parameters, adding salt can significantly increase electrical conductivity, reduce turbidity, and slightly affect pH and viscosity; (4) From the particle sizes distribution, adding salt into the oil-bearing water body can promote the aggregation of oil droplets, resulting in increased diameter of oil droplets and concentrated distribution. These indicate that inorganic salt has demulsification effect on the oil-bearing water bodies, and can significantly reduced the number of oil droplets in the water and promote oil-water demixing.Third, using gas chromatography (GC) collects fingerprints of crude oil and retention oil, and evaluating their similarity by the similarity computer software. The results are that GC fingerprints' similarity of 12 kinds of TCM volatile oil before and after membrane process is greater than 0.9, indicating that membrane does not affect the active ingredients of volatile oil; and GC fingerprints' similarity of crude oil and retention oil adding salt or not is also greater than 0.9, indicating that adding salt also does not change the active ingredients of volatile oil.Finally, using SPSS statistical software to analysis the correlation of three parts datas:salt conditions-solution environment-membrane flux/oil retention rate, to reveal the mechanism of salt demulsification elementarily before membrane separation. The results are that:the Pearson correlation coefficients between salt content and electrical conductivity, electrical conductivity and pH value, pH value and turbidity respective are 0.563**,-0.476* and 0.460*(* indicates correlation significant,** indicates correlation very significant). While the Pearson correlation coefficient between salt content and membrane average flux is 0.712**. Thus, salt conditions affect membrane flux/oil retention rate by changing physical and chemical parameters of oil-bearing water bodies. Therefore, adding salt before membrane separation can effectively promote oil-water demixing, oil droplets gather larger, are more easily retained by membrane pore, leading to oil retention rate increased; water become clear for less oil droplets and easily gets through the hydrophilic membrane, resulting in membrane flux increases, so optimizing the membrane process.The innovations of this project are that:(i) Based on "environmental solution"effect, using of demulsification of inorganic salt as a pretreatment method before membrane separation, to improve membrane flux and oil-water separation efficiency, thereby optimizing membrane process, which is a major feature; (2) Introducing demulsification of inorganic salt into membrane separation of TCM volatile oil-bearing water bodies, the salts only change the shape and size of oil droplets in water, but have no more significant impact on the structure and properties of the active ingredient, therefore this is a feasible and effective idea, which is worthy of further research and extension.