Effective degradation of Orange G and Rhodamine B by alkali-activated hydrogen peroxide: roles of HO2− and O2·−

Advanced oxidation processes offer effective solutions in treating wastewater from various industries. The process of alkali-activated hydrogen peroxide (H 2 O 2 ) was superior for the treatment of alkaline dye wastewater because no additional reagents were required except H 2 O 2 . However, an important and interesting phenomenon had been observed that the primary reactive species were found different for degrading organic pollutants with the process of alkali-activated H 2 O 2 . Azo dye of Orange G (OG) and triphenylmethane dye of Rhodamine B (RhB) were chosen as the target organic pollutants. The influences of various parameters on OG and RhB degradation by alkali-activated H 2 O 2 were evaluated. Furthermore, different scavengers, including ascorbic acid, methanol, t -butanol, isopropyl alcohol, furfuryl alcohol, and nitro blue tetrazolium, have been tested to identify the active species involved in dye degradation, and it was found that O 2 ·− was mainly responsible for degrading OG, while HO 2 − anion was the primary oxidant for degrading RhB.