(727e) Metal Organic Framework Adsorbents for Control of Toxic Industrial Chemicals

There is an increasing concern about the potential threat of chemical attacks in buildings. To protect occupants from the effect of hazardous contaminants, it is necessary to implement an efficient continuous filtering system for the air brought into the building and recirculated inside the building.  Since most buildings are equipped with mechanical heating, ventilating, and air conditioning (HVAC) systems, the filters used in these systems can be replaced or supplemented by filters containing chemical adsorbents that can remove the targeted hazardous contaminants from the air, in particular Toxic Industrial Chemicals (TICs). 

Treated and non-treated activated carbons are traditionally used to remove hazardous compounds from the air. ASZM-TEDA carbon, an impregnated activated carbon, has been used for over 15 years to remove TICs.  ASZM-TEDA is a coal-based activated carbon, impregnated with copper, zinc, silver, and molybdenum compounds, as well as triethylenediamine. One drawback is that this type of carbon does not perform efficiently for low-molecular-weight compounds and is significantly affected by humidity. Therefore, many industrial chemicals and toxic gases are not well adsorbed by currently available filters.

The presentation will summarize the testing and development of novel adsorbents for TICs control. The selected materials are known as metal organic frameworks (MOFs) and consist of metal centers coordinated with organic ligands to form highly porous materials with well-defined nanometer pore sizes. Six MOF materials and three activated carbon materials were compared to ASZM-TEDA (baseline material) for the adsorption of eight TICs including ammonia, sulfur dioxide and chlorine. It was shown that using a metal organic framework could greatly improve the building protection against ammonia and methylamine. The effect of temperature and humidity on the adsorption performance was also investigated for promising adsorbent/adsorbate pairs.

The project is funded by the Technical Working Support Group (TSWG), which operates as a program element under the Combating Terrorism Technical Support Office (CTTSO).