The influence of impurities contained in quartz sand on the catalytic reduction of nitric oxide by carbon monoxide

The catalytic activity of a natural sand, pure quartz and different quartz sand samples were tested on the reduction of nitric oxide by carbon monoxide in a fixed bed flow reactor. The natural sand shows a very high conversion of nitric oxide to nitrogen whereas pure quartz has no catalytic activity. The activity of the quartz sand samples depends on the amount of impurities present. The pollutants are not only responsible for the catalytic reaction but also for a deactivation of the catalyst at temperatures higher than 800°C. The reason for it was investigated by inverse gas chromatography, IR spectroscopy, temperature programmed desorption and differential thermal analysis, indicating a surface transformation.