In order to develop a diffusion denuder for the removal of NO2from ambient atmospheric samples, a number of materials were screened for their ability to adsorb NO2: 1. (1) MgO; 2. (2) MnO2on alpha-Al2O3; 3. (3) water-treated MnO2on alpha-Al2O3; and 4. (4) MnO2(activated). A simple cylindrical denuder coated with MnO2(activated) was very effective in the removal of NO2from a feedgas of NO2in air at ambient temperature and pressure. The other materials were unsatisfactory. The strong oxidizing properties, along with the hydrated surface of the MnO2(activated), appear to be important for the sorption of NO2, as suggested in applications elsewhere. Quantification of denuder sorption efficiencies indicates that MnO2 (activated) is nearly a perfect sorbent for NO2. The diffusion coefficient of NO2in air was found to be 10.8 ± 0.3 cm2min-1at 22-23°C, which compares favourably with a theoretical estimate. Although MnO2(activated)-coated denuders were also found to adsorb SO2, interference with NO2sorption was not sufficient to impair ambient applications. © 1986.
Adams, K. M., Japar, S. M., & Pierson, W. R. (1986). Development of a MnO2-coated, cylindrical denuder for removing NO2from atmospheric samples. Atmospheric Environment (1967), 20(6), 1211–1215. https://doi.org/10.1016/0004-6981(86)90155-1