Enhanced Ozone Oxidation by a Novel Fe/Mn@γ−Al2O3 Nanocatalyst: The Role of Hydroxyl Radical and Singlet Oxygen

Catalytic ozonation is a potential alternative to address the dye wastewater effluent, and developing an effective catalyst for catalyzing ozone is desired. In this study, a novel Fe/Mn@γ−Al2O3 nanomaterial was prepared and successfully utilized for catalytic ozonation toward dye wastewater effluent components (dimethyl phthalate and 1−naphthol). The synthesized Fe/Mn@γ−Al2O3 exhibited superior activity in catalytic ozonation of dimethyl phthalate and 1−naphthol in contrast to Fe@γ−Al2O3 and Mn@γ−Al2O3. Quench and probe tests indicated that HO° contributed to almost all removal of dimethyl phthalate, whereas O3, HO°, and singlet oxygen participated in the degradation of 1−naphthol in the Fe/Mn@γ−Al2O3/O3 system. The results of XPS, FT−IR, and EPR suggested that HO° and singlet oxygen were generated from the valence variations of Fe(II/III)and Mn(III/IV). Moreover, the Fe/Mn@γ−Al2O3/O3 system could also have excellent efficacy in actual water samples, including dye wastewater effluent. This study presents an efficient ozone catalyst to purify dye wastewater effluent and deepens the comprehension of the role and formation of reactive species involved in the catalytic ozonation system.