Degradation of nitrobenzene by high-gravity intensified heterogeneous catalytic ozonation with Mn-Fe/ZSM-5 catalysts

Abstract

In this study, high-gravity intensified heterogeneous catalytic ozonation is proposed for degradation of nitrobenzene (NB) in wastewater using Mn-Fe/ZSM-5 as the packing of the high-gravity rotating packed bed (RPB). The effects of inlet O3 concentration, liquid flow rate, initial pH, and high-gravity factor on the removal rate of total organic carbon (TOC) at room temperature are investigated and compared with that in a bubbling reactor (BR), and the degradation mechanism is also discussed. The results show that under the optimal conditions of the high-gravity factor β = 20, initial O3 concentration CO3 = 25 mg/L, liquid flow rate QL = 60 L/h, and initial pH = 6, the removal rate of TOC reaches 72% after 40 min. The removal rate of TOC in RPB is 33.5% higher than that in BR. The radical quenching experiment shows that •OH plays a dominant role in high-gravity intensified heterogeneous catalytic ozonation with Mn-Fe/ZSM-5. It is concluded that high-gravity intensified heterogeneous catalytic ozonation with Mn-Fe/ZSM-5 can effectively improve the degradation efficiency of organic wastewater.