Electrospun Co-MOF/polyacrylonitrile-derived cobalt nanoparticles supported carbon nanorods for peroxymonosulfate activated diclofenac degradation: Kinetics and mechanistic study

The creation of efficient and resilient catalysts for advanced oxidation processes (AOPs) is crucial for the effective elimination of persistent pharmaceutical contaminants from wastewater. Cobalt metal–organic framework ( Co -MOF) was effectively incorporated into polyacrylonitrile (PAN) nanofibers using electrospinning and subsequently carbonized to produce cobalt nanoparticles supported on carbon nanorods (Co/CNRs). The customized catalyst, Co/CNR-2, demonstrated evenly dispersed cobalt nanoparticles, an increased surface area, and improved electrical conductivity, which collectively enabled rapid activation of peroxymonosulfate (PMS). The catalyst Co/CNR-2 exhibited remarkable catalytic effectiveness in the degradation of diclofenac (DCF), achieving almost 99% removal after 20 min using 0.5 g/L dose of catalyst, 1.0 mM PMS, and at pH 6.0, adhering to pseudo-first-order kinetics with a rate constant of 0.194 min −1 . Radical quenching and electron paramagnetic resonance (EPR) studies confirmed that sulfate radicals (SO 4 •- ), hydroxyl radicals (OH • ), and singlet oxygen ( 1 O₂) were the primary reactive species engaged in DCF breakdown. The catalyst demonstrated exceptional structural stability and reusability over five consecutive cycles, with negligible cobalt leaching. Furthermore, Co/CNR-2 has demonstrated considerable degradation efficiency for several drugs, highlighting its broad applicability. This study presents innovative insights into the rational design of MOF-derived carbon-based catalysts and recognizes Co/CNRs as a feasible and sustainable platform for the PMS-mediated degradation of emerging organic contaminants.