Abstract:

A Fe3O4-PSF magnetic composite ultrafiltration membrane with a molecular weight cutoff (MWCO) of 33000 D was obtained by in-situ generation method. The effects of magnetic intensity and ultrafiltration pressure on retention rate were dealt with under MWCOs of 30000 and 10000 D, and it was found that the optimal magnetic intensity and ultrafiltration pressure were 0.1 T and 0.4 MPa for 30000 D MWCO ultrafiltration and 0.8 T and 0.5 MPa for 10000 D MWCO ultrafiltration, respectively. The polysaccharide-rich extract from Ophiopogon japonicus prepared in this study was continuously separated using the two MWCOs, and the fractions (A, C and D) obtained were subjected to the determination of molecular weight based on the use of the GPC software. Fraction A exhibited a molecular weight of 32610 D, and contained 85.6% polysaccharides having a molecular weight exceeding 30000 D. The molecular weight of fraction C was 24069 D, and it contained as high as 87.6% polysaccharides having a molecular weight varying from 10000 to 30000 D. Fraction D had a molecular weight of 8664 D, and the content of polysaccharides having a molecular weight varying from 1000 to 10000 D in it was as high as 88.7%.

Key words: Fe3O4-PSF magnetic composite ultrafiltration membrane, Ophiopogon japonicus polysaccharide, continuous separation, utrafiltration, HPGPC