Degradation of nitrobenzene in wastewater by O3/FeOOH in a rotating packed bed

In this study, O-3/FeOOH was used for degradation of nitrobenzene (NB) wastewater in a rotating packed bed (RPB) in order to improve the efficiency of heterogeneous catalytic ozonation, and the effects of high gravity factor beta, FeOOH concentration, inlet O-3 concentration, liquid flow rate, initial pH and initial NB concentration on the degradation rate of NB and the removal rate of COD were also investigated. The results show that under the optimal conditions (high gravity factor beta = 40, FeOOH concentration = 0.5 mg L-1, inlet O-3 concentration = 40 mg L-1, liquid flow rate = 60 L h(-1), initial pH = 7, initial NB concentration = 100 mg L-1), the degradation rate of NB reaches 100 % after 20 min and the removal rate of COD reaches 94 % after 40 min. Tertiary butyl alcohol (TBA)is added to trap hydroxyl radicals, and the results show that the oxidation by hydroxyl radicals plays a dominant role in the degradation of NB. Gas chromatography-mass spectrometry was performed to investigate the degradation intermediates and the possible degradation pathways of NB by O-3/FeOOH in the RPB were also proposed.