Chitosan/polyacrylonitrile composite nanofiltration membranes: towards separation of salts, riboflavin and antibacterial study

Chitosan is in prominence as membrane materials. The present study based on chitosan–tannic acid crosslinked moiety on polyacrylonitrile support membranes. FTIR-ATR, zeta potential, XRD, SEM, AFM, TGA, DSC and contact angle are used to understand the characters of the membranes. The separation performances of salts (NaCl, Na2SO4) proved that membranes are associated with charged nanofiltration separation behaviour. Memb-III has reached a maximum difference in salt separation performance (Na2SO4 90.88% and NaCl 35.76%) at ~ 134.4 Lm−2 h−1 compared to Memb-I and II. The membrane performances are marked with organic molecule markers (e.g. glucose and sucrose). The separation of molecular markers shows its direct relationship with its molecular size. The pH-dependent studies show that separation of riboflavin increases at pH 9 compared to separation at pH 7, whereas the reverse happens for flux. Memb-III shows a maximum 84.1% riboflavin separation having flux 55.82 Lm−2 h−1 at pH 9. The study with bacteria (viz. E. coli, Bacillus subtilis) also proves that the surface is antibacterial.