Adsorption performance of activated carbon towards toxic industrial chemicals

One of the main goals in the project “1238: CBRN-vern” was to extend the present-day knowledge on the current CBRN filter and respirator systems and their possible improvement, in order to give the Norwegian Armed Forces a necessary expertise on their operative performance. This report summarizes the literature survey carried out in connection with the project, focusing on the filter canisters based on activated carbon used in the gas masks. Together with a gas mask the filters give the necessary respiratory protection against CBRN agents and a variety of toxic gases, including Toxic Industrial Chemicals (TICs). Knowledge on the adsorption mechanisms and the materials used in the filters is a key to understand and predict their operative performance against TICs. Activated carbon is of particular interest, since its unique properties make it the most commonly used adsorbent in the filters for civilian and military applications. Here, the preparation techniques, structure, different types of adsorption, effect of humidity and possible impregnation methods of activated carbon are reviewed, and the emphasis is put on the aspects of filter performance most relevant for the military applications. Adsorption mechanisms of selected TICs on activated carbon are presented, and a brief introduction to mathematical models useful for prediction of the filters lifetime is given. Finally, the report presents the conclusions from the literature findings, as well as recommendations for the future research activities at FFI and the possible evaluation of filter performance.