| 摘要 |
A nitric oxide filtration material or filter, particularly for tobacco smoke, comprises activated carbon, preferably in particulate form, upon which has been absorbed a C-nitroso compound, any substituent group of said compound, other than a nitroso group, being such as to have no critical adverse effect on the integrity of the nitroso group. The compound is preferably an aromatic compound such as nitrosobenzene, 2-nitrosotoluene or 2,4, 6-trimethylnitrosobenzene. Suitably the carbon is coal-based. Advantageously the carbon has been loaded with a metal, such as copper or iron at a loading level in the range of 0.1% to 5% by weight on an untreated carbon basis. The loading level of the C-nitroso compound may be in the range of 2% to 15%, preferably 2% to 7% by weight. Such a filter comprising the C-nitroso compound may advantageously also comprise ventilation means. The invention also comprises a method for the filtration of nitric oxide from a gaseous medium which comprises passing the medium in contact with a filtration material as hereinbefore defined. |
