The Ultra-filtration Membrane Separation Of HT And Other Three Extracts And The Research On Effects Of Pretreatment Through Simulated Solutions

Beginning with the application of organic ultra-filtration membrane ,this project focus on how pretreatments affect Chinese herbal decoction before and after ultra-filtration and search for proper pretreatments before ultra-filtration membrane separation,so as to reduce the fouling degree of membrane and increase the preserving degree of efficiency components and enhance the comprehensive benefits of membrane separation.The project also lays a foundation for the researching of the separation mechanism of membrane while treating Chinese herbal decoction ,and for the the application of organic ultra-filtration membrane in the production of Chinese drugs preparation.At the beginning of the research ,we study on the pretreatments before ultra-filtration membrane separation of HT, RD and TA extracts respectively. we review the effects of different pretreatmental methods on getting rid of inefficacy components and on membrane separation and evaculated these pretreatments of different prescription extracts guiding with the line of the preserving degree of efficiency components the fouling degree of membrane during membrane separation.The research compared the effects of centrifugation, initial filtration, the absorbtion of active carbon and Flocculation on HT,RD and TA extracts respectively.The results show that centrifugation and initial filtration cannot reduce the fouling degree of membrane and increase the preserving degree of efficiency components very well. The absorbtion of active carbon reduces the preserving degree of efficiency components seriously, so it is not a good pretreatment for these three prescription extracts. Chitosan flocculating and micro-filtration are relatively proper pretreatmental methods, because after the treatment of chitosan flocculating and micro-filtration ,the extracts have larger membrane flux and smaller fouling degree of membrane and larger preserving degree of efficiency components in the following membrane separation process. The study does further experiments to find out the best chitosan flocculating technics for the three Chinese herbal decoctions by orthogonal test.Then we researched the problem of the reduce of membrane flux and membrane fouling.Taking the aftertreatmental decoction of Huoxuetongluo,Reduning and Tong'an as the experimental system, we studied on the reduce of membrane flux and the fouling degree of membrane and the preserving degree of efficiency components under different operational pressures,temperatures and drug thickness.Through the experiment,the proper ultra-filtration operation condition for these three herbal decoction is as follows:import pressure is 0.03 MPa～0.05Mpa, temperature is 30℃, drug thickness is approximately 0.05g/mL. Through the experiment, we also find out some proper cleaning and reusing methods about fouled membrane. After the cleaning of water 15 minites, 0.2%NaOH plus 0.1%NaClO 40minites,and then 0.3%HNO₃ 40 minites in file,the recoverry rates of membrane flux are all over 90 percent.The cleaning process is easy and it isn't time-consuming,so the cleaning method can be used to wash membrane when the membrane being seriously fouled and the membrane flux dropping sharply.Part three: Taking various macromolecule materials commonly existed in Chinese herbal decoctions as the study subject and the membrane flux change and the fouling degree of membrane and the preserving degree of efficiency components as guide line,wetry to find out the substance foudation of membrane fouling of the Chinese herbal decoction during the ultra-filtration process through the study of the quality and quatity of the simulated macromolecule solutions. Particularly we studied on the behavements of the simulated macromolecule solutions and search for the relativities between membrane flux and physical and chemical parameters and components.The experiment shows that the simulated tannin solutions cause the membrane flux to drop mostly and the fouling degree of membrane is the deepest, membrane made of PS of molecular weight of 6 thousand and thirty to fifty thousand in particular. From the aspects of tannin's molecular weight and particle size ,we may come to the conclusion that tannin is easy in entering the molecular aperture and then be absorbed in it ,causing the molecular aperture to get smaller and the membrane flux to drop quickly,so it must be removed in the pretreatment.Along with the increase of molecular aperture, the fouling degree of membrane fouled by simulated starch solution is increasing and the preserving degree of starch is decreasing.The evidence that the dropping degree of membrane flux is very low and the fouling degree of membrane is the lowest and the preserving degree of starch is very high when using PS membrane of molecular weight of 6 thousand to do ultra-filtration predicts that PS membrane of molecular weight of 6 thousand is proper to be used in treating Chinese herbal decoctions which are fat in starch. Pectin and protein can be easy removed in the ultra-filtration process, the removed degree is high and the the fouling degree of membrane is low and the dropping degree of the membrane flux is also very low. The experiment shows that the technology of membrane seperation can be used in the area of purification and enrichment of Chinese herbal decoctions which are rich in pectin and protein.Part four: the experiment is aimed to simulate the fouling situation of the membrane fouled by different macromolecule solutions, and we try to find out the effects of different pretreatments on getting rid of various pollutional materials and on the following membrane separation process. We also try to explore into and test the mechanism of how various pretreatments reduce the fouling degree of memTakingbrane.The results showed by the experiment predict that the best pretreatmental method for starch solutions is micro-filtration, while the best pretreatmental method for tannin solutions is absorbtion of active carbon and chitosan flocculating subordinately,and the proper pretreatmental methods for pectin are chitosan flocculating and micro-filtration, and the best pretreatmental method for protein is absorbtion of active carbon and chitosan flocculating and micro-filtration also have some effects on it.The innovations of this article lie in the following two ways:Firstly,it advocates the idea of cleanness of membrane from the aspects of pretreatmentTaking the effects of various pretreatments on the Chinese herbal decoction itself and after ultra-filtration as the study subject ,we research systematically from physical and chemical view and do an initial discussion about the pertinency between the physical and chemical parameters and the process of ultra-filtration. Secondly, beginning with the researchment of simulated macromolecule solutions and focusing on the physical and chemical parameters before and after membrane seperation ,we discuss the effects of different pretreatments on different solutions and the validity of different pretreatments mechanically.