Photocatalysis of naphthalene by Fe3O4/Oxone/UV: Simultaneous radical and non-radical pathways

Naphthalene (Nap) degradation by photocatalysis of Fe3O4/Oxone/UV was studied. The system eliminated Nap in 30 min and the kinetics is described by a novel mixed order model with adsorption and decay dominant rate constants, representing non-radical and radical pathways respectively. The reaction is dominated by catalysis in acidic pHs as Oxone anions are adsorbed onto the protonated Fe3O4 surface for activation; In alkaline solution, the adsorption of Nap to the deprotonated Fe3O4 surface is the main removal pathway. The catalyst was reused for 5 cycles and the performance was enhanced after reuse. XPS study confirmed that the surface Fe content of Fe3O4 remained stable after reusing due to the effective UV-assisted equivalent to Fe-II-equivalent to Fe-III catalytic cycle. An additional C-O bond on Fe3O4 surface was detected after reuse, which is proposed to be an OH bond on catalyst as an extra adsorption site and for radical generation.

Automated summary

Naphthalene degradation was successfully achieved using graphene/oxidized graphene/UV photocatalysis. The reaction is influenced by catalysis and adsorption mechanisms under acidic and alkaline conditions, with improved performance observed after reuse.