Coupling iron-based zeolitic imidazolate Framework-8 and cellulose nanofiber for efficient peroxymonosulfate oxidation

The development of biocompatible Fenton-like catalysts with outstanding activities and stabilities, using low-cost sustainable bio-sourced materials, has garnered significant attention, yet remains a substantial challenge. In this study, we successfully constructed monodispersed iron anchored on a 3D porous N-doped carbon substrate (CNF@Fe-NC) via one-step annealing of Fe-based zeolitic imidazolate frameworks (ZIFs) and bacterial cellulose nanofibers (CNFs) as highly efficient peroxide-activation catalysts. Due to abundant micropores and mesopores in the interconnected CNF support and ZIFs, even after annealing, the obtained catalysts have a specific surface area of up to 739.4 m2/g. Owing to monodispersed Fe-Nx species and abundant nanofibrous structure, CNF@FeNC exhibited outstanding catalytic stability and superior activity for peroxymonosulfate (PMS) activation toward organic contaminant oxidation, outperforming the benchmark Fenton system. Surface Fe-Nx sites and CNF defects could adsorb negatively charged PMS to produce nonradical CNF@Fe-NC-PMS* complexes and high -valent iron oxo species (FeV = O), rather than radicals and 1O2, for eliminating pollutants. The strong iron - support electronic interaction and abundant pi-conjugation in the CNF support facilitated the efficient adsorption and activation of PMS and the uniformly dispersed Fe species in CNF@Fe-NC improved atom-utilization efficiency. This study provides a clue to design biocompatible cellulosic-based Fenton-like catalysts for the removal of organic contaminants.