Microwave-induced persulfate-hydrogen peroxide binary oxidant process for the treatment of dinitrodiazophenol industrial wastewater.

• MW-PS-H 2 O 2 binary-oxidant process was firstly used to treat DDNP wastewater. • The oxidant utilization rate considerably increased with the binary oxidant process. • Both S O 4 · - and · O H were major contributions to organics degradation. Microwave (MW) irradiation is a superior approach to a warm-up system than conventional heating, and persulfate (PS) and hydrogen peroxide (H 2 O 2) can be efficiently activated to produce a reactive oxygen species for organic degradation. However, shortcomings remain regarding whether to use a low oxidant or the low treatment efficiency of a single oxidant process. In this study, a PS-H 2 O 2 binary oxidant process induced by MW was developed to treat dinitrodiazophenol industrial wastewater. The best chemical oxygen demand (COD) (73.5%) and color number (CN) (98.1%) removal efficiencies were obtained for the MW-PS-H 2 O 2 process under conditions of a total oxidant dose = 7.4 mM and n(PS)/n(H 2 O 2) = 3.7/3.7. In the MW-PS-H 2 O 2 process, the combination of ·OH and SO 4 − better degrades organics in DDNP industrial wastewater with the advantages of lower residual salinity (sulfate ions) and less invalid decomposition of excessive H 2 O 2. In addition, benzene ring substances and functional group substances were greatly degraded, and the molecular weight of the organics considerably decreased as a result of the MW-PS-H 2 O 2 process. Overall, the results demonstrate that the MW-PS-H 2 O 2 process is a promising treatment method for dinitrodiazophenol industrial wastewater with high treatment efficacy and high oxidant utilization. [ABSTRACT FROM AUTHOR]