ABSTRACT
Objective To discuss the fouling mechanism of ceramic membrane in the microfiltation of extract of Qijudihuang Wan and obtain the effective cleaning method. Method The extract of Qijudihuang Wan was microfilted in this experiment, and the distributions of filtration resistance were studied according to the Darcy-Poiseuille principle. The characteristic of the surface and section of the polluted membrane was analysed by SEM also. Result ①For the main body, the filtration resistance is mainly decided by the deposit resistance, the membrane itself and the concentration polarization resistance are less important, and the pore blocking resistance is least important. Moreover, this result is proved by the analysis of SEM. ②The effective four-step cleaning procotrol, which can almost recover original membrane flux, is achieved by three cleaner, including ultrasound, NaOH solution and HCl solution. Conclusion Based on the different fouling mechanism, the appropriate cleaning method can be obtained. This provides great significance for the application of the industrialized manufacture.
ABSTRACT
Objective To discusse the fouling mechanism of 0.2 ?m Al_2O_3 ceramic membrane in the microfiltration of Qiju Dihuang Pill aqueous extract. Methods Qiju Dihuang Pill aqueous extract was microfiltered in this experiment. The distributions of filtration resistance were studied according to the Darcy-Poiseuille principle. The substance of deposit on the membrane surface was analysed by Fourior transform infra-red spectrum and particle diameter analysis. The characteristic of the surface and cross section of the polluted membrane was observed by SEM. Results The filtration resistance was mainly concentrated on the surface of deposit resistance, the membrane itself and the concentration polarization resistance were less important, and the pore blocking resistance was the least important. Moreover, this result was proved by SEM analysis. The molecule of the fouling substance mainly contained peptid, carbonyl, and hydroxy bonds by IR. The particle size distribution of the deposit substance on the polluted membrane surface: The particle radius taking a larger percentage in volume concentrated in 18.267 ?m around, while the particle radius taking a larger percentage in quantity concentrated in 0.424 ?m around. Conclusion Study on the fouling mechanism of the membrane in the microfiltration provides a great significant guidance for exploring the effective measure of relieving the reduced membrane flux and the appropriate cleaning procotrol.
ABSTRACT
AIM: To discuss the fouling mechanism of 0.2 ?m Al_2O_3 ceramic membrane in the microfiltation of extraction of Qijudihuang Pills, and obtain the effective cleaning procotrol. METHODS: The extract of Qijudihuang Pills microfiltered and the distributions of filtration resistance were studied according to the Darcy-Poiseuille principle. The characteristic of the surface and section of the polluted membrane were analysed by SEM also. RESULTS: ① For the main body, the filtration resistance was mainly decided by the deposit resistance, the membrane itself and the concentration polarization resistance were less important, and the pore blocking resistance was minimum. Moreover, this result was proved by the analysis of SEM. ② The effective four-step cleaning procotrol, which could almost recover original membrane flux, was achieved by three cleaner, including ultrasound, NaOH solution and HCl solution. CONCLUSION: Based on the different fouling mechanism,the appropriate cleaning procotrol can be obtained. This provides great significance for the application of the industrialized manufacture.