Temperature swing adsorption of NOx over ZrO2-based oxides

Sorption/desorption properties of NOx over ZrO2-based oxides are studied to use them as solid sorbents for NOx removal at low temperatures (<150<degre es>C). The impregnation of 1 mol% PdO onto ZrO2, increased the NO uptake in the presence of O-2 by promoting the oxidation of NO to NO2 and the subseq uent formation of nitrate adsorbates. The NOx adsorbability increased with decreasing reaction temperature, giving rise to the maximum, 0.83 mmol/g, a t 30 degreesC. The reversible sorption/desorption cycles could be repeated even in the presence of CO2 by applying temperature swing operation between 30 and 500 degreesC. (C) 2000 Elsevier Science Ltd. All rights reserved.