Ozone Catalytic Oxidation of HCHO in Air over MnOx at Room Temperature

The complete oxidation of HCHO in air with O-3 over MnOx catalysts at room temperature was studied. The MnOx catalysts were prepared by a redox method. The catalysts showed amorphous patterns in X-ray diffraction characterization. Formaldehyde in simulated air containing 137 mg/m(3) HCHO with 56% relative humidity (RH, 25 degrees C) was totally oxidized to CO2 by 642 mg/m(3) O-3 over the MnOx catalysts at GHSV (gas hourly space velocity) = 2 x 10(5) h(-1). The formaldehyde conversion and CO2 selectivity were maintained at similar to 100% during 150 min time-on-stream. The effect of the molar ratio of O-3 to HCHO was also investigated. At a O-3 to HCHO molar ratio of 2:3, which was significantly lower than the stoichiometric ratio, a CO2 selectivity of 100% was still achieved. No byproduct was detected during HCHO oxidation with O-3 over the MnOx catalysts using an online Fourier transform infrared spectrometer.