Functionalized polyacrylonitrile fibers with durable antibacterial activity and superior Cu(II)-removal performance

To develop functionalized polyacrylonitrile (PAN) fibers with superior adsorption performance and durable antibacterial activity, adhesive polydopamine (PDA) layers were introduced for effective immobilization of silver nanoparticles (AgNPs). The results showed that the pre-treatment (acidization and oxidation) may lead to the slight degradation of PAN and the formation of unsaturated CC double bonds, which can significantly promote the loading of PDA and AgNPs. Further scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analyses indicated that the average sizes of the AgNPs on sulfonated PAN fibers and p-toluenesulfonated PAN fibers were 166.7 nm and 158.6 nm respectively, and their corresponding atomic percentages were 0.65% and 0.31% respectively. As expected, two functionalized PAN fibers showed excellent antibacterial activities against both gram-negative and gram-positive bacteria. Particularly, the antimicrobial ratio of the two functionalized PAN fibers could retain more than 90% after 5 laundering cycles. On the other hand, the spontaneous Cu(II) ion adsorption process followed the pseudo-second order kinetics, Langmuir and Freundlich models, and the adsorption mechanism of the two functionalized PAN fibers is the combination of surface adsorption and intraparticle diffusion. Last but not least, the two functionalized PAN fibers can be used for multiple metal ions removal simultaneously.