Structural control of cellulose nanofibrous composite membrane with metal organic framework (ZIF-8) for highly selective removal of cationic dye.

Highly durable cellulose nanofibrous composite membranes were prepared by in-situ growing of zeolitic imidazolate frameworks (ZIF-8) as spacers in the presence of TEMPO oxidized cellulose nanofibers (TOCN) as their anchoring points. The obtained composite membranes showed three-dimensionally networked nanofibers with ZIF-8 to generate porous structures, which gave high durability without critical compaction of the membrane under pressure (1∼3 bar). The 20 μm thick ZIF-8/TOCN membrane showed most superior water flux (84 Lm h bar) without critical flux drop for 24 h operation. Interestingly, the composite membrane exhibited highly selective removal of cationic dyes in the presence of anionic dyes due to strong interaction through negatively charged TOCN networks. The experimental results in the study reveal a novel strategy for durable cellulose nanofibrous membrane via introduction of metal organic frameworks for highly selective filtration.