Cellulose hollow fibers for organic resistant nanofiltration
G. Falca, V.-E. Musteata, Al R. Behzad, S. Chisca, S. P. Nunes
J. Membr. Sci. 586, 151-161 (2019)
Cellulose is the most abundant biopolymer, but it is difficult to process due to its low solubility in most of the
solvents. In this work, we demonstrate the preparation, of self-standing and defect-free cellulose hollow fiber
membranes made by a sustainable process for filtration in organic solvent medium. The hollow fibers were made
by the simple spinning technique using ionic liquids as a solvent. The spun solutions were prepared with three
different ionic liquids, having imidazolium-based cations and acetate or phosphates as anions. We used X-ray
diffraction to evaluate the influence of the different ionic liquids on the crystallinity of the cellulose and the
membrane solvent stability. We used cryo-scanning electron microscopy to investigate the porous structure of
the hydrated membranes, distinguishing it from that of the dry membranes. The hollow fiber membrane performance
was studied using dyes in water and ethanol solutions. The rejection of Congo Red (696 g mol−1) was
higher than 90% in ethanol and even closer to 100% in water. The best results were obtained by using 1-ethyl-3-
methyimidazolium diethyl phosphate and 1,3-dimethylimidazolium dimethyl phosphate. Our results indicate
that by using greener process is possible to obtain solvent resistant cellulose hollow fibers.