Abstract:To investigate the promoting catalysis of metal ions (Cu2+,Ni2+,Mn2+,Co2+,Cr3+,Fe3+) on the NaNO2-catalyzed wet oxidation of the anthraquinone dye, the Acid Blue 129 (AB129) was taken as the research substrate, and the initial AB129 concentration of 100 mg/L coupled with the molar ratio of NaNO2 to AB129 at 0.6:1 in acid aqueous media (pH 2.5) under moderate conditions (T=150℃;oxygen pressure=0.5 MPa) was used. The promoting catalysis of the different metal ions was sort by the order of Fe3+>Cu2+>Cr3+>Co2+>Mn2+≈Ni2+ based on the catalytic activity detection when the molar ratio of cocatalysts, NaNO2 and AB129 was 0.2:0.6:1. In addition, the decoloration rate reached 100% after 2 h of catalytic wet oxidation in the NaNO2/FeCl3 system. The variation of COD of the solution showed that the NaNO2/FeCl3 coupling system was better than the Fe3+ or NaNO2 catalysis alone. After 4 h of catalytic wet oxidation, the COD removal rate reached 68% in the presence of NaNO2/FeCl3, and the increment of COD removal rates compared with the Fe3+ and NaNO2 alone were 21% and 45%, respectively. The UV-visible spectrum analysis as well as the COD determination indicated that the final products of the AB129 degradation were CO2 and small molecule organic compounds. As a result, a probable mechanism of the stimulative catalytic oxidation was proposed by the cycle and transformation of M(n+1)+/Mn+、NO、NO2 and ONOOH, while ONOOH and cocatalysts were considered as the most important active oxidants.