ABSTRACT
The molecular weight of the effective components of traditional Chinese medicine( TCM) is usually less than 1 000.However, " noneffective common macromolecules"( starch,pectin and other macromolecules commonly present in the water extract of TCM) generally have no physiological activity,which restricts the overall advantages of membrane technology to obtain small molecular pharmacodynamic substances,and such macromolecules are the main influence factor of membrane fouling. Therefore,in order to obtain the total pharmacological efficacy of TCM,based on the molecular structure analysis of noneffective common macromolecules,aimed at the key scientific problems in correlation between the molecular structure of noneffective common macromolecules and the pore structure of membrane material,and by referring to the material science theory and molecular simulation method,the correlations between noneffective common macromolecules' molecular structure-solution environment-membrane antagonism were investigated. Multidisciplinary approaches could be integrated to: ① optimize the spatial form of membrane surface and improve the membrane's antifouling ability; ② accurately control the pore structure and the size distribution of membranes,aimed at the innovative preparation technology of special membrane used for TCM; ③ adjust solution environment based on the analysis of molecular structure,and establish the pretreatment method based on the optimization of solution environment. Furthermore,the technical bottleneck on how to obtain the pharmacodynamic micromolecules effectively might be solved,and the theory and technology about TCM pharmaceutical engineering could be developed based on the concept of multivariate and integration.
Subject(s)
Chemistry, Pharmaceutical/methods , Medicine, Chinese Traditional , Membranes, Artificial , Molecular Structure , Research DesignABSTRACT
Objective To prevent and treat of ceramic membrane purification of membrane fouling process of TCM extracts; To explore new methods of forecasting membrane fouling degree.Methods BP neural network model was improved. Methods to fast determine the optimal number of neurons in the hidden layer and fast algorithm for optimizing the weight and threshold of BP neural network were studied. Data of 207 groups of TCM extracts were under network training and prediction.ResultsCompared with the models of multiple regression analysis, basic BP neural network and RBF neural network, the error of the improved BP neural network model was less than that of the BP neural network model, and the mean square error was only 0.0057. In addition, the improved BP neural network model performance was more stable. In the 20 random running experiments, the goal of the success rate achieved up to 95%.Conclusion The improved model has a good network performance, the fitting effect and prediction ability, and can forecast the fouling degree of membrane stably and accurately.
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Objective: To study the influencing factors of membrane flux (J) and membrane fouling resistance (Rf) in the mincrofiltration of the water extract of Cassia Semen with ceramic membrane. Methods: Based on single-factor experiment, the process parameters in the mincrofiltration of the water extract of Cassia Semen were optimized by orthogonal design method using weighted composite score of Rf and J as evaluation. The correlation between Rf and J with main four process parameters was analyzed. Results: The best microfiltration process condition was as follow: Membrane aperture size was 0.2 μm, concentration of the water extract of Cassia Semen was 50.0 g/L, transmembrane differential pressure was 0.1 MPa, and crossflow velocity was 3.32 m/s. Membrane aperture size had a significant correlation with Rf and J. Conclusion: The process parameters have an important effect on Rf and J. The primary and secondary order of the effect of four process parameters on Rf and J is as follow: Membrane aperture size > transmembrane pressure > feed concentration > crossflow velocity.
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Objective To study the distribution of filtration resistance in AL2O3(0.2 ?m) ceramic membrane microfiltration of Tangkeqing water extract,obtain the effective membrane cleaning methods,and enrich the theory of ceramic membrane cleaning technology.Methods The filtration resistance and its distribution were got with the filtration model of the Darcy-Poiseuille principle which was modified by M.MDa-Cin,etc.Meanwhile,The microstructure of fouled membrane surface and cross-section was analyzed by SEM.Results The main parts of filtration resistance lay in deposit layer and concentration polarization layer with the ratio of 52.5% and 34.4%,respectively.However,the membrane itself and the pore blocking were in the fewer ratios of 8.8% and 4.3%,respectively.The result was in accordance with that of SEM.The fouled AL2O3 membrane was cleaned with low-pressure tap water and ultrasonic wave successirely.Conclusion The appropriate cleaning means are chosen based on the filtration resistance,which can provide good instructions for the industrialized production.
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Objective To study the fouling mechanism during the filtration of traditional Chinese medicine decoction by inorganic ceramic membrane so as to make a valuable exploration both on membrane fouling prevention and the industrialization of membrane separation technology in the field of Chinese materia medica. Methods Micro-filtrating Qingluo Tongbi Decoction using alumina ceramic membrane, researching the applicability of the membrane with different pore sizes, observing the fouling on membrane surface by scanning electron microscopy, studying the resistance distribution of membrane in filtration process, analyzing the fouling existence shape, position, and forming rule. Results In this system, alumina membrane with the pore size of 0.2 ?m was most suitable, which had the biggest permeating flux and reservation rate of effective component with less fouling. Among the alumina membranes with three different pore sizes, auto resistance and pore block resistance made up inferior percentage in total resistance, fouling resistance distribution mainly consisted of the reversible resistance, such as concentration polarization and gel layer resistance. Conclusion Optimizing parameters of the techniques in membrane process, using suitable pretreatment method and cleaning method can reduce membrance fouling and make the memberane property recover.
ABSTRACT
AIM: To discuss the fouling mechanism in 0.2 ?m Al_2O_3 commie membrane microfiltation of Tangkeqmg Compound water extract. METHODS: The total filtration resistance and its distribution were used as indexes to study the effect of pore size and materials of ceramic membrane on membrane fouling in clarification. SEM (scanning electronic microgragh) technology was used to study the microstructure of surface and section of new membrane and contammted membrane and physica and chemical examination were done on the fouling substances on the membrane surface. RESULTS: The pore size and materials of membrane affected the total filtration resistance and its distribution in clarification. The results of filtration resistance dislribution and SEM suggested that the fouling of 0.2 ?m Al_2O_3 membrane mainly lied on the surface. The contaminations on membrane surface were mostly the substances holding function groups, such as C=O, CO-NH and C-O-C. According to volume percentage, the semidiameter of contaminations on the membrane was mostly around 23.738 ?m. However, according to quantity percentage, the semidiameter of contaminations on the membrane was mostly around 0.521 ?m. CONCLUSION: Study on the fouling mechanism of the membrane is of great significance for looking for the effective measures for relieving the downward trend of the membrane flux and for the appropriate membrane cleaning in the clarification of Tangkeqing Compound extract using 0.2 ?m Al_2O_3 ceramic membrane.