Study On The Preparation Of Micro-nanocrystalline Cellulose/Polysulfone Composite Ultra-filtration Membrane And Its Performance

The micro-nanocrystalline cellulose was prepared with cellulose pulp in the way of acid hydrolyzation reaction, and then the micro-nanocrystalline cellulose was added into the casting solution to prepare the micro-nanocrystalline cellulose/polysulfone (PSF) composite ultra-filtration membrane in the immersion phase inversion process, based on reviewing the present researches of the functional utilization of cellulose and modification and preparation of ultrafiltration membrane materials. The influence factors of the preparation process were studied and the feasible preparation conditions were obtained. The feasible preparation conditions of the composite ultra-filtration membrane are as follows: the PSF mass ratio is 18%, the micro-nanocrystalline cellulose is 20% mass of the PSF, the additive is PVP K30 and its mass ratio is 0.3%, the evaporation time is 10 seconds, and the coagulation bath is water.The FIR,X-ray diffraction and thermogravimetric analysis methods were used to analyzed the composition of the composite membrane, the scanning electron microscope (SEM),atomic force microscope (AFM) methods were used to observed the surface and section of the composite membrane. The outcomes showed that the composite membrane has a typical asymmetry structure of skin layer and supporting layer. The addition of micro-nanocrystalline cellulose changed the structure of the membrane pores. Also we tested the contact angle of the material and found that the micro-nanocrystalline cellulose can improve the hydrophile ability of the membrane and raise its'performance.We tested the membrane performance in different working pressure with protein solutions in different concentrations and got the math model of the ultra-filtration which is suitable for the low concentration solutions after data processing. The anti-fouling experiment showed that the composite membrane has a better anti-fouling performance compared with the pure PSF membrane. At last, we got the ternary phase diagram of the casting solution with different micro-nanocrystalline cellulose content and the results showed the micro-nanocrystalline cellulose changed the phase inversion route and the composing of cloud point, so the structure of the membrane and its'performance were changed.