Abstract: The composite ultra-filtration membrane with polysulfone(PSF) as main body and micro/nano-crystal cellulose as filling was prepared in phase-inversion process by adding micro/nano-crystal cellulose into the PSF casting solution. Through the orthogonal experiment we get the optimal process conditions: the PSF content(wt) is 18%, the additive content of PVP K30 is 0.3%, the micro/nano-crystal cellulose added is 15% of the PSF mass, the solvent evaporation time in the air is 10 seconds, the coagulation bath medium is water. The properties such as pure water flux, rejection ratio, mean pore size, porosity and tensile strength of the composite membrane were tested. In this condition, the composite membrane's pure water flux can reach 152.72L/(m²·h), the rejection ratio of the bovine serum albumin (BSA) solution (1g/L) is 93.98%, the porosity is 63.22% and the mean pore size is about 46.03nm. The composite membrane has a good filtration performance.

Key words: composite ultra-filtration membrane, polysulfone, micro/nano-crystal cellulose, pure water flux