Pickering emulsions stabilized by salicylic acid and arginine modified titanium dioxide (TiO

2

-SA-Arg) nanoparticles were prepared in this study for photocatalytic degradation of nitrobenzene in a rotating annular reactor

and the effects of various design parameters of the rotating annular reactor

initial nitrobenzene concentration

catalyst amount

and solution pH on the degradation rate of nitrobenzene were investigated. Meanwhile

the degradation mechanism of nitrobenzene was proposed. The results show that increasing the aeration rate

the rotational speed

and light intensity results in a higher photocatalytic degradation rate of nitrobenzene owing to the effective clearance of electrons and a high quantity of oxidative free radicals. The degradation of nitrobenzene in the rotating annular reactor follows the pseudo first-order kinetics

but it is not well described by the Langmuir-Hinshelwood equation. Aeration has a significant effect on the photocatalytic degradation pathway of nitrobenzene. Because nitrobenzene can undergo reduction reaction as electron acceptors and oxidative degradation initiated by

hydroxyl free radicals

the photocatalytic degradation of nitrobenzene follows the reduction mechanism under no aeration

but the oxidation mechanism under aeration.