Removal of NOx by photocatalytic processes

The photocatalytic methods for nitrogen oxides removal were recently very intense areas of scientific research. Photo-deNOx processes offer interesting ways for abatement of these harmful gases. This review describes several methods for removing NO by photocatalytic reactions. These methods can be classified into three major groups: photo selective catalytic reduction (photo-SCR), photo-oxidation and photo-decomposition. The application of photocatalysts and photo-processes for NOx abatement in real-scale cases are presented. The fast-growing development of these methods is revealed by the large number of issued patents in photo-deNOx applications. The mechanism of NO creation and the traditional methods (primary and secondary) of NOx removal are summarized and discussed. A cooperative system that combines the traditional (thermal) process and a photo-process is then proposed for improving NOx removal efficiency.

▶ The NOx removal can be divided into two groups, primary and secondary methods. The photo de-NOx processes are classified as the secondary method. Three ways of de-NOx by photocatalytic reactions are photo selective catalytic reduction, photo-oxidation and photodecomposition.Figure optionsDownload as PowerPoint slideHighlights
► Three ways of removing NOx by photocatalytic reactions, photo-SCR, photo-oxidation and photo-decomposition are summarized.
► The mechanism of NO formation and the traditional methods of NOx removal are summarized and discussed.
► The real-scale applications of NOx removal by photo processes are presented.
► A photo-deNOx process with other primary or secondary methods is proposed in the end of the review.