A recently-developed technique for removing nitrogen oxides from waste gases makes use of a common, nontoxic organic compound known as cyanuric acid, C₃H₃N₃O₃. When heated to temperatures of about 660°F (345°C), cyanuric acid decomposes to form isocyanic acid. The acid, in turn, reacts with oxides of nitrogen to form carbon dioxide, carbon monoxide, nitrogen, and water. The process has been given the name of raprenox, which comes from the expression rapid removal of nitrogen oxides. In tests so far, the method has worked very well with internal combustion engines, removing up to 99% of all nitrogen oxides from exhaust gases. Its efficiency with gases released from smokestacks has not yet been determined.

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Scrubbers