Research On The Restraining Separation Method Of The Composite Magnetic Membrane

Polysulfone(Psf)-Fe₃O₄ composite ultrafiltration membranes with different Fe₃O₄ particle size and content were made by phase-inversion process.The preferable particle size and loading of Fe₃O₄ were fixed when researching their influence on the membrane.The characterization of the membrane was examined.The mechanism was analyzed from two aspects.One is the influence of the magnetic field and the other is geometrical deformation.Then the application of separation was researched with puerarin, Quercetin,roxerutin and Ginkgo Flavone.The results are as follows:1.The preferable particle size of Fe₃O₄ is 10nm according to AFM and pure water flux.The optimal loading of Fe₃O₄ is 20%according to the porosity and SEM.SEM,AFM showed most particles are distributed uniformly in the membrane and the mean surface roughness(RMS)was only 39.106nm in the range of the scan areas 10μm×10μm.From XPS it can be deduced that the chemical bond of Fe-O-S was builded between nano-sized Fe₃O₄ particles and polysulfone.As a result,the particles are distributed steadily in the membrane.Hysteresis curve of the nano-sized Fe₃O₄ particle and the composite membrane shows that they are super-paramagnetic.2.The Organic ultrafiltration membrane filled with nano-magnetic media will produce electromagnetic induction and geometry deformation effect of the membrane pore.●The rejection of the Psf-Fe₃O₄ composite membrane to electriferous material such as lysozyme solution andα-amylase reduced and as with the increase of electricity,the range of change increase,resulted as the interaction between the charged material and the magnetic field.●The rejection of the Psf-Fe₃O₄ composite membrane to magnetic material such as TEMPO and Gadopentetate Dimeglumine reduced,which is due to the traction it got in the magnetic field.●The rejection of the Psf-Fe₃O₄ composite membrane to diamagnetic material such as glucan and polyethylene glycol changed too.It can be considered as the geometrical deformation caused by the Fe₃O₄.3.The composite membrane has the function of selective separation under the magnetic field.The puerarin,Quercetin and troxerutin ultrafiltration with the Psf-Fe₃O₄ composite membrane in different magnetic intensities were performed respectively.The results revealed that in magnetic field,the concentration of them through membrane increased,but the trend is different from each other.Then we can achieve the continuous effective separation with the magnetic composite ultrafiltration membrane,by adjusting the applied magnetic field.4.The separation of ginkgo flavonoids from GBE with the composite membrane showed that:The content of flavonoids in the products was 30.16 wt.%from 15.60 wt.%without magnetic field,35.24 wt.%in the magnetic field of about 0.2 T.The content of ginkgo flavonoids increase acutely with the increase of the magnetic intensity initially and then to stable at 1.0 T to 52.87 wt.%.