Core-shell structured fiber as an iron ion self-reducible and self-anchorable Fenton catalyst for methylene blue high-efficient mineralization

Abstract

The combination of GO decoration, PAA wet-spinning, Fe3+/Al3+ co-coordination with PANI coating was adopted to fabricate mechanically applicable core-shell structured fiber. Since GO could rely on its abundant oxygen-containing functional groups to interact with the carboxylic groups of PAA through hydrogen bonding and esterification crosslinking, GO decoration was expected to enhance the mechanical properties and water resistance of PAA matrix. Thanks to PANI-adjusted Fe3+/Fe2+ cycling, mass content of Fe2+ in PANI-coated fiber reached 0.08%, increasing by 242% compared to that of fibrous core. After the third cycle, Fe2+ mass content was 0.09% and higher than original content, and after 60 cycles, Fe2+ mass content was still as high as 0.09%; thus the resulting fiber could quickly catalyze H2O2 to mineralize 90% of MB during cyclic application. Due to strong PANI-induced iron ion-anchoring ability, iron ion leaching was only 0.36 mg/L during 60 cycles and less than 7% of that of fibrous core, so that the PANI-coated fiber could use its retained iron species to repeatedly decolorize MB at least 60 times. Since PANI shell could serve as an all-in-one locality to ensure Fe3+/Fe2+ cycling, pollutant mineralization, and iron ion anchoring, the fiber prepared herein presented its own superiority in treating dye wastewater.