MnO_x/Al₂O₃ catalyzed ozonation for low-concentration BTX removal at room temperature

Catalytic oxidation of low-concentration benzene, toluene and p-xylene (BTX mixture) with ozone over MnO_x/Al₂O₃ catalyst was investigated in a fixed-bed flow reactor at room temperature. MnO_x/Al₂O₃ catalyst significantly promoted decomposition of O₃ and ozonation of low-concentration BTX. The optimal Mn loading amount was 5%. With inlet O₃ and BTX concentration maintained at 70 and 15 mg/m³, the conversions of benzene, toluene, p-xylene and O₃ reached 75%, 84%, 88% and 90%, respectively. The BTX conversion firstly increased and then leveled off with the increase of inlet O₃ concentration, while the O₃ conversion slightly decreased. The conversions of both BTX and O₃ decreased with the increase of inlet BTX concentration. Catalyst deactivation occurred as the reaction proceeded, which can be attributed to the buildup of organic intermediates such as aromatic aldehyde, aromatic acid and formic acid over catalyst surface during the catalytic oxidation process.